Cover photo: Kauai Cave wolf Spider used with permission of Bill Mull.
DRAFT RECOVERY PLAN FOR THE 

KAUAI CAVE ARTHROPODS: 

The Kauai Cave Wolf Spider (Adelocosa anops) 

and the Kauai Cave Amphipod (Spelaeorchestia koloana)

(November 2004)

Region 1

U.S. Fish and Wildlife Service

Portland, Oregon

Approved:XXXXXXXXXXXXXXXXXXXXXXXX

Regional Director, Region 1

U.S. Fish and Wildlife Service

Date: ___________________
i

DISCLAIMER

Recovery plans delineate reasonable actions that are believed to be

required to recover and/or protect federally listed species. We, the U.S. Fish and

Wildlife Service, publish recovery plans, sometimes preparing them with the

assistance of recovery teams, contractors, State agencies, and other affected and

interested parties. Recovery teams serve as independent advisors to us. Plans are

reviewed by the public and submitted to additional peer review before they are

adopted by us. Objectives of the plan will be attained and necessary funds made

available subject to budgetary and other constraints affecting the parties involved,

as well as the need to address other priorities. Costs provided for action

implementation and/or time for achievement of the outlined tasks and/or recovery

objectives are only estimates and subject to change. Recovery plans do not

obligate cooperating or other parties to undertake specific tasks and may not

necessarily represent the view nor the official positions or approval of any

individuals or agencies involved in the plan formulation other than our own. 

They represent our official position only after they have been signed by the

Regional Director or Director as approved. Approved recovery plans are subject

to modifications as dictated by new findings, changes in species status, and the

completion of recovery actions.

Literature Citation should read as follows:

U.S. Fish and Wildlife Service. 2004. Draft Recovery Plan for the Kauai Cave

Arthropods: the Kauai Cave Wolf Spider (Adelocosa anops) and the Kauai

Cave Amphipod (Spelaeorchestia koloana). U.S. Fish and Wildlife

Service. Portland, Oregon. 55 pp.

This draft plan is also available at:

<http://pacific.fws.gov/ecoservices/endangered/recovery/default.htm>
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ACKNOWLEDGMENTS

This plan was prepared by staff in the Pacific Islands Fish and Wildlife

Office, Honolulu, Hawaii. 
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EXECUTIVE SUMMARY

CURRENT STATUS: The Kauai cave wolf spider (Adelocosa anops) and the

Kauai cave amphipod (Spelaeorchestia koloana) are obligate cave-dwelling

arthropods restricted to the Hawaiian island of Kauai. Although it is possible

these arthropods occur in other regions, they have only been found in the Koloa

Basin of the island of Kauai where lava tubes and other cave bearing rock are

present. Currently, the Kauai cave wolf spider, a predator, is only regularly

encountered in a single cave where 16 to 28 individuals (U.S. Fish and Wildlife

Service, unpublished data 1998 and 2003) have been found during regular

monitoring visits. During recent visits, the Kauai cave amphipod has been

regularly observed in 2 caves, their numbers typically ranging from 8 to 40, but

greater than 300 individuals have been encountered in 1 of these caves, likely in

response to periodic food enhancement conducted by research biologists (U.S.

Fish and Wildlife Service, unpublished data 1998 and 2003). No population

estimates currently exist for these arthropods. Given the limited range of the

spider, it is likely its population is extremely small and especially vulnerable. 

Since the Kauai cave amphipods have been found in caves scattered through the

Koloa District, they likely have a considerably larger population and/or

populations. The existence of amphipods in geographically separate areas, may

make them less vulnerable than the Kauai cave wolf spider to catastrophic events

that might impact a single cave. Urban and agricultural development as well as

quarrying operations within the area threaten the habitat of these cave arthropods,

and non-native species likely prey upon or compete with them for limited food

resources. Human visitation and uses of caves are potentially serious threats as is

urban and commercial pesticide use and the use of biocontrol agents. Extended

drought may also threaten these species by altering the high-humidity

environment to which these arthropods are adapted and facilitating invasion by

nonnative species.

LIMITING FACTORS AND HABITAT REQUIREMENTS: Both the Kauai

cave wolf spider and the Kauai cave amphipod have, or are believed to have, low

reproductive rates compared to their non-cave dwelling counterparts. Food is

believed to be limiting in most cave systems and this appears to be true in the

Koloa caves as well. These species are believed to live in inaccessible

mesocaverns as well as large cave passages which means their populations are
iv

almost certainly greater than the numbers observed. However, few of the known

caves in the Koloa District provide appropriate habitat for these arthropods which

are typically only found in the Dark and Stagnant Air Zones (two of five cave

zones typified by low air movement, elevated relative humidity, and reduced

temperature fluctuations) of caves and require high humidity conditions. The

limited number of occupied caves greatly limits our knowledge of the life history

requirements of these arthropods. 

Given the cryptic nature of caves and the uncertain distribution of

inaccessible mesocaverns, our knowledge of the distribution and population status

of these two species is greatly limited. 

RECOVERY OBJECTIVE: The objective of this recovery plan is to provide

guidance that will protect an adequate number of occupied caves (see Recovery

Criteria section below) spread across the known range containing self-sustaining,

stable (those in which observed population declines are followed by population

increase to pre-decline levels) or increasing populations of both the Kauai cave

wolf spider and amphipod, leading to the downlisting or recovery and ultimately

delisting of one or both of these species. The number of caves needed to downlist and de-list both species is based on the best available information, including:

the nine caves that have been located to date that are known to presently or

historically support Kauai cave arthropods; and the presence of land formations,

such as lava rock out-croppings, that indicate the potential presence of additional

caves that may be suitable. These areas were identified in the critical habitat rule

for these species (U.S. Fish and Wildlife Service 2003), and will be investigated

for the presence of suitable habitat and cave arthropods, as funds become

available. The need to identify additional occupied habitat for both species, but

especially for the Kauai cave wolf spider, is strongly encouraged. Habitat

enhancement will be a vital component of recovery for both species in most cases.

RECOVERY CRITERIA: Downlisting to threatened may be considered for

both species when nine viable populations, spread across the known range, are

shown to be: (1) self-sustaining; (2) stable or increasing; (3) protected from nonnative/predatory species, human visitation to caves, bio-control agents, pesticides,

development or other damaging land uses; and (4) with the habitat being utilized

in a fashion consistent with conservation, as evidenced by monitoring over a 10-

year period. 
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Delisting of both species may be considered when 12 viable populations,

spread across the known range, are shown to be: (1) self-sustaining; (2) stable or

increasing; (3) protected from non-native/predatory species, human visitation to

caves, bio-control agents, pesticides, development or other damaging land uses;

and (4) with the habitat being utilized in a fashion consistent with conservation,

as evidenced by monitoring over a 20-year period. The 20-year monitoring

period was determined to be necessary because land development is slated to

occur, during the first 10 years of monitoring, on lands over areas that are known

or suspected to contain caves that may support the Kauai cave arthropods. These

activities may cause significant changes in cave environments and cause

fluctuations in these species’ populations. An additional period of at least 10

years following development will be needed to ensure that the cave arthropods,

which have probable low fecundity, are stable, and that these species are

responding appropriately to natural events that may be affecting their population

levels. Also, a post-delisting monitoring plan and agreement to continue postdelisting monitoring must be in place and ready for implementation at the time of

delisting. Monitoring populations following delisting will verify the ongoing

recovery and conservation of the species and provide a means of assessing the

continuing effectiveness of management actions.

ACTIONS NEEDED:

1) Protect known populations of the Kauai cave wolf spider and Kauai cave

amphipod and their subterranean systems from human-caused destruction

or degradation.

2) Improve or enhance the habitat of occupied caves or caves previously

occupied through protection of above-cave habitats and implementation of

landscaping actions that are likely to increase subterranean food resources.

3) Conduct research to address essential conservation needs for the species.

4) Conduct public outreach to facilitate better public understanding of and

support for conservation of these cave arthropods.

5) Validate recovery objectives.

6) Develop a post-delisting monitoring plan.
vi

 Total Estimated Cost of Recovery ($1,000):

YEAR NEED 1 NEED 2 NEED 3 NEED 4 NEED 5 NEED 6 TOTAL

 01 238 15 372 10 10 1 646

 02 288 15 372 10 10 1 696

 03 248 10 370 10 10 1 649

 04 238 10 340 10 10 1 609

 05 218 10 340 10 10 1 589

 06-20 2,010 75 1,130 60 150 16 3,441

Total 3,240 135 2,924 110 200 21 6,630

Recovery plans delineate reasonable actions presumed essential to recover

and/or protect listed species. The costs and dates of recovery presented in this

plan are preliminary estimates only. Additional information and project

implementation are needed to provide a better estimate of down- and/or delisting

costs. All estimates are provided with the assumption that additional occupied or

restorable cave systems will be located.

Date of Recovery: Downlisting to threatened status may be reached by 2014,

and delisting may occur by 2024 if recovery criteria are met.
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TABLE OF CONTENTS

I. INTRODUCTION

A. Brief Overview ..................................................................................... 1

B. Description and Taxonomy .................................................................. 4

C. Life History .......................................................................................... 6

D. Habitat Description .............................................................................. 9

E. Current and Historic Range and Population Status ............................ 13

F. Reasons for Decline and Current Threats ........................................... 16

1. Habitat Destruction by Agriculture .................................. 16

2. Habitat Destruction by Urbanization ............................... 18

3. Human Visitation to Caves .............................................. 19

4. Non-native, Invasive Organisms ...................................... 20

5. Pesticides and Bio-Control Agents .................................. 21

6. Random Events and Small Numbers ............................... 21

G. Site-specific Threats ........................................................................... 22

1. Koloa Caves ..................................................................... 22

2. Cave 1927C ...................................................................... 23

3. Cave 3179 ........................................................................ 23

4. Kiahuna Caves ................................................................. 23

5. Quarry Cave ..................................................................... 25

6. By-Pass Cave ................................................................... 25

7. Saint Rafael Church Cave ................................................ 26

H. Conservation Efforts .......................................................................... 26

I. Recovery Strategy ............................................................................... 29

II. RECOVERY

A. Objectives and Criteria ...................................................................... 33

1. Downlisting Criteria ............................................................... 33

2. Delisting Criteria ..................................................................... 33

B. Narrative Outline of Recovery Actions .............................................. 35

III. IMPLEMENTATION SCHEDULE ......................................................... 45

IV. REFERENCES ........................................................................................... 50

A. Literature Cited ................................................................................. 50

B. In Litt. References .............................................................................. 54

C. Personal Communication ................................................................... 55
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LIST OF TABLES

Table 1: Distribution, current status, threats, and management activities for

the Kauai cave wolf spider ........................................................... 30

Table 2: Distribution, current status, threats, and management activities for

the Kauai cave amphipod ............................................................. 31

Table 3: Cross-reference of recovery actions and listing factors for the

Kauai cave wolf spider and the Kauai cave amphipod ................ 44

LIST OF FIGURES

Figure 1: Presumed and known distribution of the Kauai cave wolf spider

and amphipod ................................................................................. 2

Figure 2: Photograph of the Kauai cave wolf spider ..................................... 5

Figure 3: Photograph of the Kauai cave amphipod ....................................... 5
1

I. INTRODUCTION

A. Brief Overview

The Kauai cave wolf spider (Adelocosa anops Gertsch) and the Kauai

cave amphipod (Spelaeorchestia koloana Bousfield and Howarth) (collectively

the Kauai cave arthropods) represent monotypic species, both of which are only

known from caves, subterranean cracks, and mesocaverns (voids and inaccessible

passages) of the Koloa Volcanic Series on the island of Kauai, Hawaii (Bousfield

and Howarth 1976). The cave amphipod is a detritivore, feeding on plant

material, especially roots that penetrate into the caves, while the cave wolf spider

is a predator which feeds opportunistically on other cave inhabitants, including

the cave amphipod. As with other obligate cave-inhabiting species, the Kauai

cave arthropods are restricted to specific habitats or zones within subterranean

habitats. 

We, the U.S. Fish and Wildlife Service, listed both the Kauai cave

arthropods as endangered species on January 14, 2000 (U.S. Fish and Wildlife

Service 2000) and designated critical habitat for both arthropods on April 9, 2003

(U.S. Fish and Wildlife Service 2003). Both species’ recovery priority number is

1, indicating a high degree of threat and high recovery potential (U.S. Fish and

Wildlife Service 1983).

The Koloa Series Lava Flows (Lagenheim and Clague 1987) represent the

most recent volcanic activity on the island of Kauai, with the youngest rocks

dating to about 600,000 years before present (Macdonald et al. 1960). Lava tube

systems throughout most of the island are far older than those of the Koloa Series,

most caves having long since collapsed or filled with sediments (Howarth 1981). 

Therefore, these unique species are restricted to a relatively small area of Kauai

Island within the Koloa District (Figure 1) (Howarth 1981). 

Although many caves in the Koloa District have been surveyed, most do

not contain the optimal climatological conditions required by cave-dwelling

organisms, including the Kauai cave arthropods. Of the caves surveyed to date,

the cave wolf spider has only been documented to occur in five caves, and

currently is only observed regularly in one of these caves. The cave amphipod

has been documented to occur in nine caves, and is currently observed regularly 
2
3

in two of these caves. Due in part to sampling regimes, only two of these caves

contain Asizable@ or regularly observed populations of amphipods. Other

organisms frequently co-inhabit these caves. The endemic Hawaii cave isopod

(Hawaiioscia parvituberculata) is occasionally observed, as are a number of nonnative (alien) arthropods that are facultative cave-dwellers (Atroglophiles@; e.g.,

American cockroach (Periplaneta americana), brown violin spider (Loxosceles

rufescens), and the spitting spider (Scytodes longipes)).

Since Polynesian and European arrival, the Koloa District has undergone

drastic and rapid change (Cuddihy and Stone 1990). Palaeontological finds

indicate, prior to Polynesian colonization, the area supported vegetation indicative

of a wide range of habitats (xeric to mesic) (Burney et al. 2001), but human

alteration of the landscape, typically with the use of fire for agricultural purposes,

led to the removal of native vegetation (Cuddihy and Stone 1990). With

European colonization, the rate of habitat destruction increased as new

agricultural crops and practices were established (e.g., sugar cane cultivation,

ranching). In addition, numerous non-native, invasive plants readily colonized

these areas, contributing to alteration of the above-ground habitats (Howarth

1981). European agricultural practices, including burning of cane and overgrazing by goats and cattle, greatly accelerated the rates of erosion and soil loss

(Cuddihy and Stone 1990; Burney et al. 2001). Sedimentation as well as

intentional filling of caves has likely contributed to habitat loss for these and

other cave-dwelling organisms (Bousfield and Howarth 1976; Berger et al. 1981;

Howarth and Stone 1993). Modern development of the Koloa District is not

restricted to areas suitable for agriculture (i.e., well developed soils). Continued

development for housing and tourism also occurs in rocky areas originally spared

by earlier agricultural development, leading to the potential destruction of the

remaining cave habitats in the area. While development is currently one of the

most serious threats to the habitats of these arthropods, cave habitats are also

vulnerable to alteration from increased human entry and vandalism (Howarth

1982; Culver 1992; D. Hopper, in litt.1999; Culver et al. 2000), pesticides, and

non-native, invasive wildlife species, most of which either compete with the

endangered cave species for food resources or directly prey on them (Howarth

1973; A. Asquith, in litt. 1994a; D. Hopper, in litt. 1999).
4

B. Description and Taxonomy

Kauai cave wolf spider

The Kauai cave wolf spider (Adelocosa anops) is a member of the wolf

spider family, Lycosidae. Spiders in this family have a world-wide distribution

and are characterized by a distinctive eye pattern, including two particularly large

eyes located within the middle row of eyes (Foelix 1982). While wolf spiders are

typically visual predators, the most conspicuous physical character of the Kauai

cave spider is its complete lack of eyes (Figure 2). This character is unique

among wolf spiders and, in part, provides justification for the recognition of a

separate genus for this taxon (Gertsch 1973). Other species of wolf spider have

reduced eyes, including another cave-adapted species on the island of Hawaii, but

the Kauai cave wolf spider is the only lycosid in which the eyes are entirely

absent. Adults of the Kauai cave wolf spider are about 12.7 to 19.0 millimeters

(0.5 to 0.75 inches) in total body length with a reddish-brown carapace, pale to

silvery abdomen, and beige to pale orange legs. 

The hind margin of each chelicera (biting jaw) bears three large teeth, two

situated basally, and the third at the distal end of the chelicera. The tibiae of the

two anterior pairs of legs have four pairs of ventral spines, and the tarsi (ultimate

segments) and metatarsi (mid-leg segment) of all legs bear unusually long, silky,

and shiny trichobothria (sensory hairs). Doctor Frank Howarth of the Bishop

Museum first discovered the Kauai cave wolf spider in Koloa in 1971, and it was

formally described by Willis Gertsch of the Bishop Museum (Gertsch 1973). 

Kauai cave amphipod

The Kauai cave amphipod (Spelaeorchestia koloana) (Figure 3) was

discovered in some of the same caves as the Kauai cave wolf spider in 1971

(Bousfield and Howarth 1976). Because of the unusual attributes of a highly

reduced pincher-like condition of the first gnathopod (thoracic appendage) and

the second gnathopod being mitten-like in both sexes, this taxon is placed in its

own unique genus (Spelaeorchestia) within the family Talitridae (Bousfield and

Howarth 1976). This species is also distinctive in its lack of eye facets, lack of

pigmentation, and extremely elongate, spiny, post-cephalic appendages. Adult

cave amphipods are 7 to 10 millimeters (0.25 to 0.4 inches) in length with a 
5

Figure 2. Photograph of a Kauai cave wolf spider with egg case; used

with permission of Gordon Smith.

Figure 3. Photograph of a Kauai cave amphipod; used with permission of

Bill Mull.
6

slender, laterally compressed body and a hyaline cuticle, giving it a shiny,

translucent appearance. The second pair of antenna are slender and elongate, with

the flagellum (terminal antennal segments) only slightly longer than the peduncle

(proximal antennal segments). Peraeopods (abdominal walking legs) are very

elongate, with slender, tapering claws. All pleopods (swimming legs) are

reduced, with branches vestigial or lacking. Uropods (tail plates or appendages) 1

and 2 have well-developed stocks, and brood plates in the mature female are

vestigial or entirely absent (Bousfield and Howarth 1976). The Kauai cave

amphipod is a detritivore and has been observed feeding on the roots of

Pithecellobium dulce (Manila tamarind) and Ficus sp. (fig), rotting roots, sticks,

branches, and other plant material washed into, or otherwise carried into caves, as

well as the fecal material of other arthropods. In large cave passages, most

individuals are found in association with roots or rotting plant debris. When

disturbed, this cave amphipod typically moves slowly away rather than jumping

like other amphipods. Nothing is known of the reproductive biology of this

amphipod, but the vestigial brood plates of the female suggest they give birth to a

small number of large offspring (Poulson and White 1969; Bousfield and

Howarth 1976).

The great majority of amphipods (order Amphipoda) are marine

organisms. However, a large number have invaded both terrestrial and freshwater

habitats, mostly in the tropics. Hawaii now has at least two species of

widespread, introduced, terrestrial amphipods, but it also has no less than seven

species of indigenous or endemic amphipods (including Spelaeorchestia; Nishida

1992). Amphipods have invaded cave environments throughout the world, and

other cave-dwelling species are recognized as endangered or vulnerable to

extinction (U.S. Fish and Wildlife Service 1997; International Union for

Conservation of Nature (IUCN) 1994).

C. Life History

Kauai Cave Wolf Spider

Unlike most spiders, wolf spiders do not hunt with the use of a web,

relying on their sensory structures, camouflage, stealth, and swiftness to capture

prey. The Kauai cave wolf spider may either stalk its prey or utilize sit-and-wait
7

ambush tactics (Howarth 1981). Lacking eyes, it is believed vibration as well as

tactile and chemosensory cues are of primary importance in prey detection and

capture. While the cave wolf spider will likely consume the endemic cave

amphipod, as with most species of spider it will prey on virtually any other cave

inhabitant it can capture and kill, including alien spiders.

The cave wolf spider has a very low rate of reproduction when compared

to terrestrial wolf spiders of similar size (Howarth 1981; Foelix 1982). Howarth

(in Gertsch 1973) reported a female with an egg sac containing 14 spiderlings and

it is believed that 30 offspring or fewer are produced per brood (Howarth 1981;

Wells et al. 1983); this is far less than the clutch size exhibited by most terrestrial

wolf spiders which may have 100 to 300 spiderlings per brood. Based on

captured individuals, it is estimated this species takes up to a year to reach sexual

maturity (Howarth 1981). Similar K-reproductive strategies (low reproductive

rate; high investment in off-spring; long period to maturity for off-spring) are

observed in other cave-dwelling species (Howarth 1981).

Kauai cave amphipod

The Kauai cave amphipod is a detritivore, feeding on dead organic matter,

typically plant material, found on the cave floor. Within the known caves, food

for the amphipod is derived from either perennial plant roots or from plant

material that has been washed, fallen, or otherwise transported into caves. 

Amphipods and other cave detritivores (e.g., isopods, millipedes) are often

numerous around decomposing woody material on the cave floor. While some of

this woody material is derived from root masses of plants, some has been

intentionally provided by researchers as a food source for the amphipods and

other cave arthropods, since root systems are now greatly reduced or absent from

some caves. In one of the known occupied caves, woody material is periodically

washed in via a perennial stream.

It is also thought that the cave amphipod has a low reproductive rate. 

Although it is not known how many offspring are produced per brood, the

presence of a vestigial brood plate or the complete lack of a brood plate suggest

that a small number of large offspring are produced (Poulson and White 1969,

Bousfield and Howarth 1976).
8

Kauai Cave Arthropods

As with other obligate cave-dwelling arthropods, the Kauai cave

arthropods are largely restricted to the ADark Zone@ (see section D below for a

description) of caves with limited air flow, only occasionally being found in areas

where there is no surface light penetration, but where external climatic changes

(daily) still influence the cave microhabitat (i.e., ATransition Zone@). The

occupied microclimates within caves of the Koloa District are relatively constant,

with temperatures ranging from 23 to 26 degrees Celsius (73 to 78 degrees

Fahrenheit) and high relative humidity (typically at or near 100 percent)

(Bousfield and Howarth 1976; U.S. Fish and Wildlife Service, unpublished data

1998). Such micro-climatic conditions appear to be necessary for survival, or are

preferred by these arthropods and other Hawaiian cave-dwelling species (Hadley

et al. 1981; Ahearn and Howarth 1982). Howarth has shown that these

arthropods occupy the mesocaverns in the surrounding rocky substrate and will

readily enter larger passages, where they may be observed, when microclimate

conditions become favorable (Howarth 1983).

Like other cave-dwelling organisms, the Kauai cave arthropods exhibit

behaviors that suggest reduced metabolism relative to related above-ground taxa. 

This is apparent both in the spider=s outward behavior as well as their rate of

oxygen consumption (Hadley et al. 1981). As observed within its cave

environment, the Kauai cave wolf spider does not expend large amounts of effort

moving quickly through the cave environment as does its close epigean (surfacedwelling) relatives. While epigean wolf spiders are extremely active and swiftmoving, the Kauai cave wolf spider spends long periods waiting motionless or

moving slowly and deliberately over the cave floor. If disturbed, the spider may

run for a short distance, but quickly stops and returns to its normal slow pace or

again becomes motionless. Similarly, the Kauai cave amphipod is slow moving

relative to other marine or terrestrial amphipods.

Both Howarth (1983) and Huppop (1985) have postulated that cavedwelling species may be adapted to cope with low levels of oxygen and/or

elevated concentrations of carbon dioxide, similar to conditions encountered in

other caves (see section D). The ability to survive and thrive under these
9

conditions has been substantiated from field observations in known Stagnant Air

Zones (see section D below) (Howarth and Stone 1990) as well as under

controlled laboratory experiments. Hadley et al. (1981) conducted experiments

with Hawaiian wolf spiders, both cave-dwelling species (Lycosa howarthi) and a

related surface-dwelling species (Lycosa sp.). These researchers found the

surface-inhabiting spider had a higher metabolic rate, requiring 2.5 times more

oxygen as did its cave-dwelling relative. The reduced need for oxygen would

better allow these spiders to survive in Stagnant Air Zones. Given the ability of at

least some cave-dwelling species to cope with reduced oxygen and elevated

carbon dioxide, as well as their ability to inhabit mesocaverns, it seems likely

many cave-dwelling species will be able to reside in areas not readily surveyed by

biologists. Hence, cave animal habitats will typically extend well beyond

surveyable passages and connect other large caverns and passages either

accessible or inaccessible to researchers (Howarth 1983). 

Both the Kauai cave wolf spider and amphipod are sensitive to habitat

climatic conditions. They, as well as other cave-dwelling species, require a

habitat with high ambient humidity or they quickly die of dessication (Barr 1968;

Ahearn and Howarth 1982; Howarth and Stone 1990). Caves lacking high

humidity conditions do not typically contain cave-dwelling species in Hawaii or

elsewhere (Howarth 1983). For this reason, Hawaiian caves with even small

amounts of air-flow typically lack cave-dwelling animals since air circulation

usually reduces ambient humidity levels. In addition, caves with reduced

humidity appear to be far more prone to invasion by alien cave-dwelling species. 

On Kauai, the alien cave-dwelling brown violin spider has been observed to

become a dominant member in caves where conditions appear to be sub-optimal

(i.e., reduced relative humidity) for native cave-dwelling animals (see sections D

and F) (U.S. Fish and Wildlife Service, unpublished data 1998).

D. Habitat Description

The Koloa Basin of Kauai

Caves currently known to be occupied by the Kauai cave wolf spider and

amphipod include both lava tubes and subterranean passages in upraised,

calcareous marine deposits (limestone and beachstone). The lava tubes and
10

mesocaverns within the local basalt flows were formed by the Koloa Series

Volcanic eruptions that occurred from between 600,000 years before present to

1.5 million years before present (Macdonald et al. 1960; Langenheim and Clague

1987). In addition to these lava tubes, there are a number of calcareous geologic

features (i.e., up-raised marine deposits, limestone) present along portions of the

southeastern coast which lie adjacent to the Koloa Volcanic flows. Like the

volcanic cave-bearing rock in the area, the calcareous cave bearing rock also

contain inaccessible mesocaverns and passages that provide appropriate habitat

for cave-dwelling animals (Howarth 1991). It is likely the Kauai cave wolf spider

and cave amphipod invaded younger limestone formations from adjacent, older

lava tubes (Bousfield and Howarth 1976). 

Although the Koloa Volcanics cover large portions of western Kauai, the

flows of the Koloa Basin represent the youngest of those flows. Lava tubes are

not common in the north and east-central portion of Kauai. This is attributable to

the greater age of the flows (i.e., more developed soils) and weather patterns that

keep these portions of the island wetter. These factors have resulted in the

sedimentation and filling of older lava tubes. In contrast, the Koloa Basin lies in

the rain shadow of Haupu Ridge and is much drier. Compared to the older flows

of the Koloa Series to the north, soil development in the Koloa Basin has been

poor. The Waikomo-Kalihi-Koloa soil association, which covers most of the

Koloa Basin, is shallow, rarely exceeding 1 meter (3 feet 3 inches) (Foote et al.

1972). These factors have contributed to a relatively high density of lava tubes

persisting in the area.

Cave Zonation

Howarth (1991) divided cave habitats into five distinct zones. These are:

(1) the Entrance Zone, where light penetration is high and surface vegetation is

typically present; (2) Twilight Zone, which extends from the point where

vegetation ends to where light no longer penetrates; (3) Transition Zone, where

there is no light penetrance, but where external climatic changes (daily) still

influence the cave microhabitat; (4) Dark Zone, which maintains its own

microhabitat with little influence by surface air temperatures; and (5) Stagnant

Air Zone, an area similar to the Dark Zone, but where air circulation is extremely

low and the ambient gas composition is primarily controlled by in situ
11

decomposition of organic material and oxygen influx from the surface being

limited (Howarth and Stone 1990; Howarth 1991). Cave-dwelling animals are

typically found within and are most strongly associated with the Dark Cave and

Stagnant Air Zones. 

Both the Dark Cave and Stagnant Air Zones are characterized by low air

movement which results in reduced temperature fluctuations and elevated relative

humidity. Typically, this is the result of a particular cave section being a Adead

end@ passage and/or having internal geologic features, shapes, or orientation that

greatly reduce air flow, such as a low ceiling(s), collapsed ceiling, or small

squeeze passage(s). Under such conditions, water vapor may be trapped, creating

conditions of high relative humidity. In some cases, the Dark Zone may have

elevated carbon dioxide concentrations. The Stagnant Air Zone, or Abad-air@

zone, is found either deep in a dead end passage or is otherwise largely isolated

from passages that readily connect with the other cave zones. In the Stagnant Air

Zone, high carbon dioxide and reduced oxygen concentrations prevent most

facultative cave-inhabiting species (troglophiles) from colonizing these areas, but

these conditions are apparently preferred by most cave-dwelling species (Howarth

and Stone 1990). Both the Transition Zone and even the Twilight Zone may

occasionally contain cave-dwelling species, but this observation is rare. Some

cave-inhabiting species may share portions of the Dark and Stagnant Air Zones

with cave-dwelling forms, but are typically far less abundant in these two zones

(Howarth and Stone 1990). The reduced abundance or absence of noted nonnative (alien) predators (see section F on Threats), suggests the alien predators

may be poorly adapted to the Dark Zone (U.S. Fish and Wildlife Service,

unpublished data 2000). This observation deserves further research and, if

substantiated, could contribute to conservation efforts for the endangered fauna

(see sections G and H).

The trophic organization of caves is much different than surface

communities (caves typically regarded as food-limited). Terrestrial ecosystems

rely on photosynthesizing plants to provide a foundation for the upper trophic

levels of the food web. Deep caves lack plants and typically rely on nutrient input

from surface environments. Nutrient import in many mainland cave systems

comes from the use of cavern spaces by trogloxenic species (temporary cave

visitors), such as roosting bats. These trogloxenes provide a food base which is
12

derived from surface foraging areas and deposited in roosting caves in the form of

guano (Culver 1986). These nutrient sources serve as growing media for

nonphotosynthetic chemotrophs (an organism that oxidises such compounds as

hydrogen sulfide to obtain energy; the organism does not use light to produce

food) such as fungi and bacteria which, in turn, serve as a food source for other

obligate cave animals, fulfilling a similar role as do plants in surface ecosystems. 

Other cave systems rely almost entirely upon plant and detrital debris being

washed into the cave by surface water, which then provides a food base for

animals living within the cave (Barr 1968; Howarth 1983; Culver et al. 2000).

Hawaiian caves lack trogloxenic organisms in numbers sufficient to

provide an adequate food base, relying instead on the penetrating roots of surface

plants which are then grazed upon by cave-inhabiting species. For this reason,

Hawaiian cave habitats must be close enough to terrestrial plant communities to

provide sufficient quantities of root biomass in order to support healthy caveinhabiting communities. This requirement means that woody, long-lived plants

need to be present over the cave to ensure a dependable food supply is available. 

While some food import can occur from organic and detrital material being

washed into caves, this is a relatively uncommon scenario in Hawaiian cave

ecosystems.

The majority of caves in the Koloa District known to regularly contain one

or both of the Kauai cave arthropods, are shallow (i.e., near surface) lava tubes

that contain Dark Zone habitats with relatively warm, constant temperatures and

high relative humidity. The Koloa District is unique in that it is one of the few

places in Hawaii where limestone or karst geologic features occur as deep

deposits, capable of forming extensive subterranean habitats. 

Due to a number of factors, both anthropogenic and natural (e.g.,

degradation of caves due to geologic processes; see section E), only three caves

(which currently regularly support cave arthropods [U.S. Fish and Wildlife

Service, unpublished data 1998 through 2003]) with Dark Zone attributes are

known to exist, on the island of Kauai. Anthropogenic factors have greatly

accelerated the rate of natural habitat degradation, range constriction, and

fragmentation (see section F). 
13

E. Current and Historic Range and Population Status

The Kauai cave wolf spider and Kauai cave amphipod represent

monotypic species, both of which are only known from caves, subterranean

cracks, and mesocaverns and historically were likely found throughout the Koloa

Volcanic Series on the island of Kauai, Hawaii. Since its discovery in 1971, the

Kauai cave wolf spider has been reported from five caves distributed across the

Koloa Volcanic Series. These caves have been named: Koloa Cave 1, Koloa

Cave 2, Kiahuna Mauka Cave, Kiahuna Makai Cave, and the Quarry Cave. Since

its discovery in 1971, the Kauai cave amphipod has been reported from nine

caves. These caves consist of: Cave 1927C, Cave 3179, Koloa Cave 1, Koloa

Cave 2, Kiahuna Mauka Cave, Kiahuna Makai Cave, Saint Rafael Church Cave,

By-Pass Cave, and the Quarry Cave.

The Kauai Cave Wolf Spider

Currently, the Kauai cave wolf spider is only known to regularly occupy a

single cave system, referred to here as Koloa Cave 2 located in the southwest

corner of the range of the cave arthropods. Since annual to biannual monitoring

first began in 1996, this cave has routinely contained 16 to 28 spiders per

monitoring visit (U.S. Fish and Wildlife Service, unpublished data 1996, 1998

through 2003). Although new-born spiders have not been observed, both

subadult and adult spiders are regularly observed and females with egg sacs are

occasionally seen. These observations suggest this cave and the surrounding

cave-bearing rock contains a healthy breeding population of cave wolf spiders. In

an adjacent cave (Koloa Cave 1), some 200 to 300 meters (260 to 390 feet)

distant, there is only a single record from 1998 of an adult cave wolf spider being

present (U.S. Fish and Wildlife Service, unpublished data 1998 through 2003). 

This is likely due to the drier conditions of the latter cave. Koloa Caves 1 and 2

are lava tubes that parallel one another and which are likely connected by small

mesocaverns inaccessible to humans. 

Prior to an April 2000 visit, a small, but persistent population of cave wolf

spiders was known to be present in a third cave, Kiahuna Makai (Makai: coastal,

in reference to down-slope of the mountainous interior) Cave, located in the

middle portion of the range of the cave arthropods. Annual to biannual
14

monitoring visits have been conducted from 1996 to the present. One to four

individuals have been observed per visit through October of 1999, after which no

wolf spiders have been observed in this cave (U.S. Fish and Wildlife Service,

unpublished data 1996, 1998 through 2003). Providing a reason for the decline or

disappearance of the wolf spider can only be speculative, but the regular presence

of brown violin spiders in this cave, as well as a lengthy drought in the Hawaiian

Islands, may have had a serious combined impact on the wolf spiders through

competition, predation, and dessication of the cave environment. 

The cave wolf spider has been recorded in Kiahuna Mauka (Mauka:

mountain, in reference to up-slope of the coast) Cave, located approximately 883

meters (2,896 feet) from Kiahuna Makai Cave. This cave contains the largest

known population of the Kauai cave amphipod, but the wolf spider has only been

observed on one occasion (1998), in which two adult spiders were found during a

single monitoring visit (U.S. Fish and Wildlife Service, unpublished data 1996

through 2004). The lack of regular observations of wolf spiders in this cave

suggests those previously observed spiders may have been dispersing individuals

that failed to become established in this cave. The presence of wolf spiders in

this cave suggests the ability of these spiders to re-colonize this cave should

conditions become optimal. 

The Quarry Cave, a coastal cave derived from calcareous marine deposits,

is located in the southeast corner of the range of the cave arthropods. This cave is

located within a large limestone bench that follows the coastline. There have

been sporadic visits to the Dark Zone of this cave where the wolf spider has

recently been observed (Howarth, pers. comm., 2003).

The Kauai Cave Amphipod

The Kauai cave amphipod is currently known to regularly occupy two

caves in the Koloa District. It commonly occurs with the wolf spider in Koloa

Cave 2, but in relatively low numbers (8 to 32 individuals per monitoring visit)

(U.S. Fish and Wildlife Service, unpublished data 1996 through 2004). During

wetter years, the amphipod has been recorded from the adjacent Koloa Cave 1,

but in even lower numbers, and it has not been recorded from that cave since

1996 (when two individuals were observed) (U.S. Fish andWildlife Service,

unpublished data 2003).
15

Cave 1927C is a newly found cave and associated mesocaverns with the

verified occurrence of the Kauai cave amphipod. A single amphipod was

observed in the cave after humidity experiments were conducted by Bishop

Museum staff in 2002, corroborating the prediction that these arthropods live

within the intermediate-sized voids in lava and colonize caves where their

preferred environment is approximated (Howarth 2003).

The Kauai cave amphipod was observed in Cave 3179 in June 1972 when

part of the cave was moist. This cave has not been revisited until recently (2002). 

Currently, the cave is too short and dry to support the obligate cave species

(Howarth 2003).

The cave amphipod has been most abundant in Kiahuna Mauka Cave

where numbers have ranged from 11 to 306 individuals (U.S. Fish and Wildlife

Service, unpublished data 2003). Prior to 1998, amphipod numbers ranged from

11 to 40 individuals, but after quantities (1 to 2 pounds) of supplemental food

(dry wood) was deposited in this cave (spring of 1998), amphipod numbers

climbed dramatically. It is possible that the observed increases were due to

amphipods being drawn into the area from the surrounding mesocaverns by the

increased food supply (Howarth 1983). However, at their peak (after food

supplementation), juvenile and subadult numbers were nearly twice that of the

adults, whereas prior to food supplementation, the adult to juvenile ratio was less

pronounced. The high juvenile to adult ratio suggests the supplemental food may

have led to a population increase of the resident amphipods. The surface area of

this cave is currently managed as a golf course fairway. As a result, the abovesurface area receives regular watering, resulting in a consistently saturated (i.e.,

high relative humidity) Dark Zone, which is beneficial to the resident amphipods.

Seventy-one cave amphipods were recorded in the Kiahuna Makai Cave

during a visit in January 1999 (U.S. Fish and Wildlife Service 1999). Annual to

biannual monitoring visits have been conducted from 1996 to present. No

amphipods were observed prior to 1999 and after this visit (U.S. Fish and

Wildlife Service, unpublished data 1996-2004). Providing a reason for the

decline or disappearance of the amphipod can only be speculative, but the regular

presence of brown violin spiders in this cave, as well as a lengthy drought in the
16

Hawaiian Islands, may have had a serious combined impact on the amphipods

through predation and dessication of the cave environment. 

Two caves containing amphipods were observed only during a short

window of time. The By-Pass Cave, located adjacent to Waikomo Road in the

upper northwestern corner of the range of the cave arthropods, was discovered in

the fall of 1999 when heavy equipment punctured the cave roof while grading the

new Koloa By-Pass Road. This cave had previously been open to the surface and

there were signs of human use of the cave from Polynesian to the modern era

(post World War II), but the cave had been partially filled and sealed with topsoil

as recently as 20 years ago. During surveys of the By-Pass Cave, conducted in

November 1999, 40 cave amphipods were detected as well as some cave isopods

(Dave Hopper, in litt. 1999). After these surveys were completed and the cave

mapped, the cave was resealed and the road diverted to avoid impacts to the cave. 

A park was designed over the cave and native plants were used in landscaping

which are likely to provide the necessary roots for food for the amphipods.

The second cave, Saint Rafael Church Cave, is located in the upper middle

portion of the range of the cave arthropods and was only known to be surveyed on

one occasion in which amphipods were found (A. Asquith, in litt. 1994a). Since

then, the entrance to the cave has not been relocated and its current condition is

unknown.

The last cave known to be occupied by the amphipod is the Quarry Cave. 

Sporadic visits to the Dark Zone of the Quarry Cave have found the amphipod to

be present in numbers to suggest a population, but they are not always present at

every visit. During a visit to the cave in 2003, this cave contained 20 amphipods

(U.S. Fish and Wildlife Service, unpublished data 2003). 

F. Reasons for Decline and Current Threats

1. Habitat Destruction by Agriculture

With the establishment of Polynesian populations in the Hawaiian Islands

1800 years ago, endemic plant communities throughout the lowlands began to be

exposed to anthropogenic modifications (Kirch 1982; Cuddihy and Stone 1990;

Allen 1997; Athens 1997). Wet lowlands were especially prized for taro
17

cultivation, but some Polynesian settlements also diverted water to create more

arable lands in drier habitats. Much of the land preparation resulted in the

clearing of native perennial vegetation. 

With European contact and colonization (starting in 1778), land

modifications accelerated over large areas with a wider diversity of habitats being

affected. While Polynesians utilized fire to clear land (Kirch 1982), the practice

was also frequently employed by European settlers to clear land for cattle

ranching and other agricultural crops. Clearing land with fire destroyed perennial

plants growing above caves. The establishment of introduced ungulates such as

cattle (Bos taurus), goats (Capra hircus), and sheep (Ovis aries), both managed

and feral populations, have greatly altered the vegetative communities of the

islands, resulting in the denuding of vast areas and soil disturbance, preventing

plant regrowth and greatly accelerating erosion (Cuddihy and Stone 1990; Hobdy

1993). Along with the above modifications, Europeans also introduced alien

plants and converted vast areas into grasslands to support ranching operations,

resulting in the destruction of cave food chains since grasses and many of the

dominant, non-native perennials do not provide adequate root systems for

herbivorous cave-dwelling species such as the amphipod.

Beginning in 1835, the cultivation of sugar cane became an important

economic venture in Hawaii, with pineapple cultivation becoming important some

time around 1900 (Cuddihy and Stone 1990). Not only did this land use clear

large surface areas of native, perennial vegetation, resulting in the destruction of

root systems necessary for cave ecosystems, but the frequent crop rotation and

heavy rain in many of these areas significantly increased erosion and soil loss. 

Increased erosion has resulted in increased soil deposition within many low

elevation caves (Howarth 1981). It is known that soil deposition rates have

increased dramatically over the past 200 years, with greater than 2 meters (6.5

feet) of soil being deposited at one site in the Poipu area during that period. This

recent 2 meter (6.5 feet) deposition accounts for approximately 50 percent of the

sediment deposited over a period of 6,700 years at this coastal site (Burney et al.

2001). Much of the Koloa/Poipu area was cleared and many caves with openings

or mesocaverns located in areas of arable soil were filled with erosional deposits,

intentionally filled for public safety concerns, or were used as garbage pits

(Howarth 1973; A. Asquith, in litt. 1994b). All of the caves where the Kauai cave
18

arthropods are currently known to exist show signs of filling with sediments

(Howarth 1981).

2. Habitat Destruction by Urbanization

While former land use spared many rocky cave-containing areas located in

substandard agriculture land, more recent land uses are not bound by the same

constraints and pose a renewed threat. Many of the newer land uses do not rely

on the presence of deep, well-developed soils. Current development includes the

construction of roads, housing, golf courses, and a quarrying operation. In other

areas, modern technologies have allowed for the importation of soils into

otherwise unsuitable sites. As a result, the most recent development plans have

the potential to include areas with rocky substrates that had not been modified

previously for agricultural purposes.

Previous land modifications have certainly resulted in the destruction of

cave and mesocavern habitats as well as the isolation of some of the cavedwelling arthropod populations. Even with the protection of known, occupied

habitat, habitat destruction most likely continues to be a threat to these species

since unknown mesocaverns are certainly present and may provide important

habitat, corridors, and refugia for these cave-dwelling species. Ongoing or

anticipated development in the Koloa District projected over the next 10 years,

will likely result in destruction and fragmentation of cave habitats. Destruction

and filling of intervening caves and mesocaverns may confine populations of

cave-dwelling species to caves without climatic refugia (e.g., cracks and

mesocaverns with high relative humidity), increasing chances of local extinction

during periods of prolonged drought. Smaller, isolated populations of cave

arthropods will have a greater likelihood of extinction due to chance events, and

their isolation means these areas will not be able to receive recruits from or

provide colonists to adjacent cave systems. 

Caves are periodically exposed during construction activities and this can

result in the dessication of cave habitats and provide access to alien species (see

below). When caves are exposed during construction activities, most are

backfilled with the intent to fill the subterranean mesocaverns that might weaken
19

or compromise the overlying structure(s). Hence, construction frequently results

in outright destruction of cave habitats.

Lastly, urbanization typically results in large areas being covered by

asphalt or other artificial surfaces which lack or have only limited permeability. 

Rain water is diverted into storm drains and lined gutter or drainage systems,

resulting in reduced local ground water recharge. This may greatly reduce

humidity levels within caves, resulting in the dessication and loss of suitable

habitat. 

3. Human Visitation to Caves

Human visitation to and uses of caves are recognized as being a

potentially serious threat (Culver 1986). Cave ecosystems may be affected by the

following activities: used as sites for dumping and filling, contaminated by

surface sources which enter caves via streams and/or ground-water seepage, and

mining and quarrying. In addition, Polynesians utilized caves as burial sites and

many of the caves in the Koloa District show signs of this use (Hammett and

Tomonari 1978; Hammett et al. 1988). It is not known if Polynesian use of such

cave systems impacted the Hawaiian cave arthropods. Caves often attract

curiosity seekers who, in most cases, have no intent to damage the geologic or

cultural features within caves, or harm the indigenous wildlife (Howarth 1982,

1983; Culver 1986). However, cave ecosystems are sensitive to even minor

human intrusion and disturbance, and it is often necessary to limit human entry

into caves to protect the resident organisms and their habitat. 

The narrow passages in many caves will increase the chances that human

visitors may inadvertently and unknowingly crush or injure ground-dwelling

cave-inhabiting species. Human use of caves can result in the destruction of food

resources such as root systems, which are critical to most Hawaiian cave systems. 

Cave visitors may leave trash or toxic materials in caves, both of which can have

devastating effects. In Hawaiian caves, discarded food and trash can attract

arthropods (e.g., cockroaches) that can compete with the resident cave-dwelling

animals, and elevated numbers of such scavengers may attract non-native

predators (e.g., centipedes, spiders) that may prey on the natural cave inhabitants

(see Non-native, Invasive Organisms section below). Discarded trash can also
20

attract social insects such as ants which have had a devastating impact in cave

systems in Texas (U. S. Fish and Wildlife Service 1994) and have likely had

similar impacts in Hawaii (Howarth 1985; Cole et al. 1992). 

Nicotine, contained in cigarette smoke, is a powerful insecticide that can

have devastating effects in the cave environment (Howarth 1982). Due to the

confined and still air typically encountered in the Dark Zones of caves, cigarette

smoke is not readily carried out of the cave and it may disperse into cavedwelling animal-occupied mesocaverns, or upward onto the walls and ceiling of

the cave, areas that would otherwise not be affected by human activities in the

larger passages. In a similar fashion, use of open fires in caves and cave openings

may have massive, unseen impacts on cave-dwelling species both from the

release of toxic fumes as well as from drying the cave interior, reducing relative

humidity (Howarth 1982).

4. Non-native, Invasive Organisms

Non-native predators are known to feed on mainland cave-dwelling

species (U.S. Fish and Wildlife Service 1994) and certainly can be assumed to

compete with resident cave-dwelling animals for common food resources which

are already in low supply. In the Hawaiian Islands, Howarth (1981) has

documented the potential replacement of an endemic cave-dwelling spider,

Erigone stygius, by a non-native web-building cave-dwelling spider, Nesticus

mogera. While the Kauai cave wolf spider will feed on introduced cockroaches,

small alien spiders, and other introduced cave-dwelling species, there is good

evidence to suggest that it is preyed upon by the non-native brown violin spider

(Loxosceles rufescens; A. Asquith, in litt. 1994a, b; D. Hopper, in litt. 1999),

which would also feed indiscriminately on resident arthropods that would

otherwise serve as prey for the cave wolf spider. Web-building spiders, such as

the brown violin, may pose a particularly serious threat since webs present a

method of predation to which the Kauai cave wolf spider and cave amphipod are

likely not adapted (Howarth 1981). Lastly, the introduced lesser brown scorpion

(Isometrus maculatus) and centipedes (Scolopendra spp.) have both been

observed in some of the caves inhabited by the endemic cave-dwelling species

and the generalized diet of these predators would certainly include both the Kauai

cave wolf spider and amphipod. 
21

5. Pesticides and Bio-control Agents

Of great importance is household pesticide use and its potential impacts to

cave ecosystems. Urban and household use of pesticides is often higher and less

target-specific than pesticide use for agricultural crops (Hawaii Office of State

Planning (HOSP) 1992). For example, numerous household and resort pesticide

applications are for subterranean pests such as the Formosan ground termite

(Coptotermes formosanus) as well as a variety of turf pests such as ants and

cutworms, which feed on root systems. Hence, moisture runoff and recharge that

originates in urban areas may inadvertently deliver high concentrations of

insecticides or other pesticides (e.g., herbicides, fungicides) into cave and

mesocavern habitats, with potentially devastating effects on the Kauai (and other)

cave animals.

The presence of septic tanks and leaching fields associated with urban

development in cave-bearing rock is likely of mixed benefit to the Kauai cave

animals. Leaching fields would increase soil moisture levels and elevate the

relative humidity within local caves, and could result in increased food import

(i.e., detritus). However, they are equally likely to be a source of toxic and

caustic wastes in the form of household cleaners such as drain-cleaners, bleach,

and discarded chemicals.

Bio-control agents (living organisms used to control pests) are usually

perceived as preferable to the use of chemicals because they represent less of a

threat to human health and generally do no stimulate resistance in pests. Some of

these organism, however attack species other than their intended targets and have

caused or contributed to the decline and extinction of several Hawaiian insects

(Howarth 1983; Howarth 1991). For example, bio-control agents such as Bacillus

bacteria, which have been used for mosquito control, have caused serious damage

to non-target species of insects (Howarth 1991). Unlike most pesticides, biocontrol agents will not break down or decay. Should they become established,

they will likely remain resident in the area, spread to new areas with suitable host

arthropods and become impossible to eliminate.

6. Random Events and Small Numbers

All of the caves may be threatened by prolonged drought, either brought

about by global climatic changes or by local alteration of the vegetation that may
22

reduce rainfall or otherwise result in reduced soil moisture content. Prolonged

drought may desicate the cave interior, making it less accommodating to cavedwelling animals (Howarth 1983). As a result of reduced humidity, Dark Cave

and Stagnant Air Zones may become more prone to invasion by damaging, nonnative species such as the brown violin spider mentioned above and in the Section

G. on Site-specific Threats (below).

Small populations are demographically vulnerable to extinction caused by

random fluctuations in population size and sex ratio and to catastrophes such as

hurricanes (Soulè 1983; Gilpin and Soulè 1986). In addition, the low

reproductive potential of both cave species (less than 10 percent of their surface

relatives) means that they require more time and space to recover from a

disturbance than would similar animals living on the surface (F. Howarth, in litt.

2001).

G. Site-specific Threats

1. Koloa Caves

Koloa Caves 1 and 2 are currently protected by the landowner in a

cooperative agreement with the U.S. Fish and Wildlife Service. Both caves are

gated. Despite this protective action, both of these caves are still vulnerable to

other threats. The overlying area is dominated by alien grasses and non-native

perennial vegetation which may lack roots that penetrate into the cave (grasses) or

be toxic or not the preferred food (non-native perennials). Hence, the roots of

native plants with which these arthropods evolved are no longer present and much

of the non-native vegetation overlying these caves may not provide a ready source

of such root material. Many of the non-native plants are highly vulnerable to fire,

which is far more likely to occur with the current level of human activity in the

area. Fire above the cave would likely kill any perennial plants that currently do

provide roots into the caves and mesocaverns thereby jeopardizing the food base

of the resident cave-dwelling arthropods. 

Although not abundant, the brown violin spider has been found regularly

in Koloa Cave 2. This spider is implicated in the predation of the cave wolf

spider in Kiahuna Cave Makai (see below). All observations of this spider have
23

been in the lower section, where the cave becomes drier and where the native

cave-dwelling animals are less frequently encountered. While speculative, it is

plausible the limited distribution of the violin spider is due to its poorer

performance in cave areas which exhibit the characteristics of the true Dark Zone

(i.e., high humidity, reduced air movement).

Koloa Cave 1 is far drier than Cave 2 and the two endangered cavedwelling arthropods have only been encountered rarely, when conditions were

more optimal (e.g., heavy rains contributing to elevated relative humidity). The

threats discussed for Koloa Cave 2 are the same for Koloa Cave 1.

2. Cave 1927C

Cave 1927C is not gated and is vulnerable to unauthorized entry by

humans. This cave is threatened by insufficient food sources. The overlying area

is dominated by alien grasses and non-native perennial vegetation which may lack

roots that penetrate into the cave (grasses) or be toxic or not the preferred food

(non-native perennials). Many of the non-native plants are highly vulnerable to

fire, which is far more likely to occur with the current level of human activity in

the area. Fire above the cave would likely kill any of the non-native perennial

plants that currently provide roots into the caves and mesocaverns thereby

jeopardizing the food base of the resident cave-dwelling animals.

3. Cave 3179

Cave 3179 is also not protected by a gate and is vulnerable to

unauthorized entry by humans. This cave is subjected to similar threats mentioned

in Cave 1927C. These include insufficient food sources, and threats of fire.

4. Kiahuna Caves

Kiahuna Makai Cave is not gated, making the threats of human visitation,

overuse, and vandalism more acute. The Makai Cave has recently shown signs of

elevated human use which could impact the Kauai cave-dwelling arthropods if

either of these species still utilize this cave. The more biologically significant
24

Kiahuna Mauka Cave is gated and a native plant restoration program has begun

above the cave system. 

The Kiahuna Makai Cave occurs below undeveloped, unprotected lands. 

The current drought conditions may be affecting the use of this cave by cavedwelling species due to the reduced relative humidity of the Dark Zone. The nonnative dry shrubland that overlies this cave is vulnerable to fire and its destruction

could lead to accelerated degradation of the below-surface habitat by destroying

the limited root-derived food base. 

The Kiahuna Makai Cave contains a large number of the non-native,

brown violin spiders, with as many as 26 of these spiders being counted during a

single monitoring visit. Violin spiders make a strong, disorganized ground web,

in which the remains and living specimens of the cave wolf spider have been

found entangled (D. Hopper, in litt., 1999). While no direct observations of

predation by the violin spider on the endangered wolf spider have been observed,

these observations and the steady decline of wolf spiders in the presence of violin

spiders, suggests these non-native spiders may be a significant threat to the Kauai

cave wolf spider and may play an equally damaging role to other native cavedwelling species. The absence of the violin spider from the extremely humid dark

zones of other caves, where both the Kauai cave wolf spider and amphipod are

most frequent, suggests the Dark Zone conditions are less suitable for the violin

spider. 

The Kiahuna Mauka Cave is currently threatened by decreased food

import due to the overlying golf course. The majority of this cave lies under a

maintained lawn that lies adjacent to a golf course fairway. Prior to construction

of the current golf course, this area was under cultivation for sugar cane. Hence,

appropriate perennial vegetation, capable of providing root systems to

herbivorous cavernicoles (plant-eating cave dwellers), have been absent from this

site for many years. This population unit of amphipods has likely subsisted on

old decaying roots and supplemental food provided by biologists. It is possible

that this population unit would eventually decline or disappear if food was not

periodically provided by biologists. A native plant restoration program has been

implemented above the cave by the previous landowner to enhance the habitat of

the species. To date, this enhancement activity has been subject to an infestation
25

of the rose beetle (Adoretus sinicus [Burmeister]), a non-native insect which eats

the native vegetation that has been planted. This infestation has substantially

hindered the success of this project. 

Factors that pose threats to other caves in the Koloa area are less of a

concern in the Kiahuna Mauka Cave. Threat of unauthorized entry is of reduced

concern in this cave since its opening lies in an area of monitored private land. 

Current management of this area has included regular watering (golf course

maintenance) which has contributed to the maintenance of saturated soils and a

high humidity cave interior which favors cave-dwelling species and increases

rates of cellulose decomposition (a source of food to native detritivores such as

the amphipod). Lastly, although employed by the golf course, herbicides are

sparingly used and no traces of common pesticide components were detected in

soil or tissue samples (from nonnative cockroaches) that were collected and

analyzed from either of the Kiahuna caves (U.S. Fish and Wildlife Service 2000). 

5. Quarry Cave

The habitat conditions within the Quarry Cave are not optimal for cavedwelling arthropods throughout the entire cave, being drafty and of low relative

humidity throughout most of the accessible passages. Food importation into this

cave occurs primarily as a result of stream-born detrital material rather than from

the root systems of perennial plants. Although the bedrock in which this cave is

located is being quarried, the quarrying activities are minor and do not, at this

time, appear to be near the known population unit of the amphipod. However, it

is likely other mesocaverns within calacareous deposits were previously

destroyed by the quarrying operation. Future increases in quarrying activity could

negatively impact the underground spring that flows into this cave and/or cause

the collapse of known or unknown caverns or mesocaverns. This cave is

currently gated. 

6. By-Pass Cave

This cave currently lacks an opening to the surface which protects it from

direct human entry and/or vandalism. The primary known threat for this cave is

low food abundance. Prior to re-closure of this cave, approximately 20 pounds of

native wood were treated for non-native invertebrates (i.e., frozen) and placed in
26

the cave as a food source for the resident cave-dwelling species. The Koloa ByPass Route was slightly rerouted and the land overlying the cave opening was

annexed into an adjacent county park. Most of this cave lies beneath the county

park and preservation of the cave should be compatible with use and management

of the park.

7. Saint Rafael Church Cave

The current condition of the Saint Rafael Church Cave is unknown at this

time. We have been unable to relocate the cave entrance which is believed to be

near a cemetery. However, it is likely the cave is subject to common threats such

as inadequate food source, lack of proper humidity, and if there is an accessible

entrance to the cave, threats from human visitation and alien species.

H. Conservation Efforts

The Kauai cave wolf spider and cave amphipod were listed as endangered

species on January 14, 2000 (U.S. Fish and Wildlife Service 2000). An

endangered species is defined in section 3 of the Endangered Species Act as any

species that is in danger of extinction throughout all or a significant portion of its

range. A threatened species is defined as any species that is likely to become an

endangered species within the foreseeable future throughout all or a significant

portion of its range.

The Endangered Species Act provides several opportunities for the

conservation of listed endangered and threatened animals and plants. Listed

animal species receive protection against take. The term Atake@ is defined as to

harass, harm, shoot, wound, kill, trap, capture, or attempt to engage in any such

conduct. AHarm@ is further defined to include significant habitat modifications or

degradation where it actually kills or injures listed species by significantly

impairing essential patterns that may affect breeding, feeding, or sheltering (50

Code of Federal Regulations (CFR) 17.3). Federal agencies must ensure that their

actions do not jeopardize the continued existence of a listed species or adversely

modify its designated critical habitat. The Endangered Species Act also prohibits

possessing, selling, delivering, carrying, transporting, or shipping in interstate or
27

foreign commerce any listed fish or wildlife species except as permitted under

provisions of section 10 of the Endangered Species Act.

When a species is listed as endangered or threatened under the

Endangered Species Act, it is automatically added to the State of Hawaii=s list of

protected species (Hawaii State Division of Forestry and Wildlife, Hawaii

Revised Statues 195D4). Hawaii State Law prohibits taking of endangered

wildlife and encourages conservation by State government agencies. 

Critical habitat for the Kauai cave arthropods was designated on April 9,

2003 (U.S. Fish and Wildlife Service 2003). 50 CFR '424.02 defines critical

habitat to be the specific areas currently occupied by a species on which are found

those physical or biological features that are necessary for the recovery of the

species and that may require special management considerations or protection,

and those areas unoccupied by a species that the Secretary of Interior has

determined to also be essential for the recovery of the species. AConservation@ is

further defined as the use of all methods and procedures that are necessary to

bring any endangered or threatened species to the point at which the measures

provided by the Endangered Species Act are no longer necessary. The critical

habitat designation consists of 14 units whose boundaries encompass an area of

approximately 110 hectares (272 acres) on the island of Kauai, Hawaii. This

critical habitat designation requires us to consult under section 7 of the

Endangered Species Act with regard to actions carried out, funded, or authorized

by a Federal agency. 

A number of programs within the U.S. Fish and Wildlife Service provide

funds and incentives for the protection of federally listed species. In 1995 a

cooperative agreement with one private landowner was initiated and conservation

measures agreed to by the landowner and the U.S. Fish and Wildlife Service are

being implemented (U.S. Fish and Wildlife Service, in litt. 1995) . This

conservation agreement and a subsequent agreement, focus on habitat protection

and enhancement as recovery strategies for these two species. 

A cave preserve management plan (the plan) was developed for three

units, incorporating Koloa Caves 1 and 2 (considered together as a single unit),

Cave 1927C, and Cave 3179 on property owned by Alexander and Baldwin. The
28

goals of the plan are to reduce threats that affect the endangered cave arthropods,

stabilize their populations, and maintain their ecosystem into the future. The

long-range goal is recovery of the two species and eventual removal from the List

of Threatened and Endangered Species. The plan relies on experimentally

modifying the surface and interior environments in caves that do not currently

support the two species. The proposed plan is adaptive, changing as the results of

monitoring and research become available since recommendations for the

conservation of these species is hampered by the lack of good ecological data

concerning their requirements.

In 1997, the Federal Highways Administration informally consulted with

the us to avoid or minimize their impacts to a cave uncovered during a road

construction project (Koloa By-Pass Road; see ABy-Pass Cave@ section above). 

Working in cooperation with the county and a private landowner, this cave was

protected from potential damage due to road construction when the road was

slightly diverted to avoid the cave and minimize impacts to the area above the

cave. Supplemental food was placed in the cave prior to re-sealing the entrance

and the cave opening was annexed into an adjacent county park. Improvements

to the area above the cave by the Kauai Department of Parks (the installation of a

watering system and the planting of two genus of trees, Senna sp. and Erythrina

sp.) are likely to enhance the amphipods habitat. These improvements will likely

enhance the habitat for the resident amphipods because they will provide plant

roots into the cave and help maintain a high humidity environment. 

Unfortunately, monitoring the biotic responses to these conservation and recovery

efforts is not possible at this time because the cave was sealed.

A summary of the known distribution, status, threats, and current

management actions for the Kauai cave wolf spider is presented in Table 1.

A summary of the known distribution, status, threats, and management

actions for the cave amphipod is presented in Table 2. Based on the known

distribution of the Kauai cave amphipod, it is plausible they exist in more

population units and larger numbers, throughout a larger area than the cave wolf

spider with occupied caves occurring as far distant as 5 kilometers (3.1 miles)

from one another. 
29

I. Recovery Strategy

This recovery plan outlines steps for the immediate and long-term

protection and enhancement of cave habitats for the Kauai cave wolf spider and

cave amphipod. Downlisting and delisting of the cave arthropods may be

achieved through the protection and appropriate habitat enhancement of the

known, occupied caves, as well as discovery of additional occupied caves, and

reestablishment of stable or increasing population units into formerly occupied

caves (e.g., Kiahuna Makai Cave). Given the restricted distribution of these

arthropods, the limited number of occupied sites, and the potential threat to their

habitat from human activities, preservation of known occupied habitats is a

priority for the recovery of these species.

Kauai Cave Wolf Spider

Given that the cave wolf spider is only regularly found in a single cave, it

is extremely vulnerable to extinction, both from catastrophic events as well as

from fluctuations in the resident population. It also means the wolf spider=s

recovery is contingent on the discovery of additional occupied caves, and/or the

enhancement of known but unoccupied caves, to the point where they can support

the wolf spider, and the implementation of appropriate protection and habitat

enhancement. In order to preserve this species, the protection and enhancement

of the single occupied cave is of fundamental importance and must be a priority

focus of any recovery strategy.

Kauai Cave Amphipod

For the Kauai cave amphipod, protection and habitat enhancement of the

known, occupied caves is a priority which will contribute to the downlisting of 

this species. Locating and protecting additional occupied caves will be necessary

for the downlisting and delisting of the cave amphipod. In addition, the apparent 

population rebound observed in the Kiahuna Mauka Cave after food

supplementation suggests this arthropod will respond favorably and quickly if

conservation activities succeed in protecting and enhancing occupied habitat. 
30

Table 1. Distribution, current status, threats, and management activities for the

Kauai cave wolf spider (Adelocosa anops). Terms are defined as: Common:

always observed during monitoring visits and in numbers suggesting a

resident population; Rare: only observed periodically and not present in

numbers that indicate a reproducing population; Historic: previously observed

and believed to have been Acommon,@ but recently absent.

CAVE SPECIES 

STATUS

KNOWN

THREATS

CURRENT 

MANAGEMENT ACTIONS

Koloa

Cave 1

Rare

Dry cave interior, non-native

predators, low food abundance,

drought, vulnerable surface habitats

(fire), pesticides.

Access controlled by locking

gate; surface area over cave

protected by agreement with

landowner.

Koloa

Cave 2 Common

Dry cave interior, non-native

predators, low food abundance,

drought, vulnerable surface habitats

(fire), pesticides.

Access controlled by locking

gate; periodic food

supplementation; surface area

over cave protected by

agreement with landowner.

Kiahuna

Makai

Cave

Historic

Dry cave interior, non-native

predators, low food abundance,

drought, vulnerable surface habitats

(fire), pesticides, unauthorized

human entry.

Surface area not currently

threatened by development or

modification.

Kiahuna

Mauka

Cave

Rare Non-native predators, pesticides.

Surface area over cave managed

as golf course; watering

enhances cave habitat; access

controlled by locking gate; cave

habitat enhancement through

surface habitat management from

previous landowner. 

Quarry

Cave

Rare

Non-native predators, low food

abundance, drought, habitat

destruction (quarry), vulnerable

surface habitats (fire), pesticides.

Access controlled by locking

gate at one of three entrances;

not currently managed or

protected.
31

Table 2. Distribution, current status, threats, and management activities for the

Kauai cave amphipod (Spelaeorchestia koloana). Terms are defined as:

Abundant: always observed during monitoring visits and numbers often

exceeding 100 individuals; Common: always observed during monitoring

visits and in numbers suggesting a resident population; Present: not always

observed during monitoring visits, but present in numbers to suggest a

population; Rare: only observed periodically and not present in numbers that

indicate a reproducing population; Historic: previously observed and believed

to have been Acommon,@ but recently absent; Currently Unknown: previously

observed, no current information.

CAVE SPECIES

STATUS

KNOWN 

THREATS

CURRENT 

MANAGEMENT ACTIONS

Koloa Cave 1 Rare

Dry cave interior, non-native

predators, low food abundance,

drought, vulnerable surface

habitats (fire), pesticides.

Access controlled by locking gate;

surface area over cave protected by

agreement with landowner.

Koloa Cave 2 Present

Dry cave interior, non-native

predators, low food abundance,

drought, vulnerable surface

habitats (fire, pesticides).

Access controlled by locking gate;

periodic food supplementation; surface

area over cave protected by agreement

with landowner.

Cave 1927C Rare

Dry cave interior, unauthorized

human entry, non-native

predators, low food abundance,

drought, vulnerable surface

habitats (fire), pesticides.

Surface area over cave protected by

agreement with landowner.

Cave 3179 Historic

Dry cave interior, unauthorized

human entry, non-native

predators, low food abundance,

drought, vulnerable surface

habitats (fire, pesticides).

Surface area over cave protected by

agreement with landowner.

Kiahuna Mauka

Cave

Present to

abundant

Non-native predators. Surface area over cave managed as golf

course; watering enhances cave habitat;

access controlled by locking gate;

periodic food enhancement; cave

habitat enhancement through surface

habitat management from previous

landowner.

By-Pass Cave Currently

Unknown

Low food abundance. Cave is closed; above surface watering

and landscaping should enhance cave

habitats.

Saint Rafael Church

Cave Currently

Unknown

Dry cave interior, unauthorized

human entry, non-native

predators, low food abundance,

drought, vulnerable surface

habitats (fire), pesticides.

Not currently managed or protected.

Quarry Cave Present Non-native predator; low food

abundance, drought, habitat

destruction (quarry), vulnerable

surface habitats (fire),

pesticides. 

Access controlled by locking gate at

one of three entrances; not currently

managed or protected.
32

For the Kauai cave arthropods, habitat enhancement of unoccupied caves

may be a viable recovery tool. However, in caves not known to have been

occupied by one or both of these species, such Arestoration@ activities should not

be considered as a feasible tool until such enhancement methods are proven to be

effective. Emphasis needs to be placed on protection and enhancement of known

occupied caves and the discovery and protection of additional caves. In addition,

non-native predators will need to be eradicated in a way that will not be a

detriment to the native spider, such as targeted removal of violin spiders.
33

II. RECOVERY

A. OBJECTIVES AND CRITERIA

The objective of this recovery plan is to outline recovery actions that,

when implemented will remove threats to the existing cave arthropod populations,

and establish within their historic range, or locate, new populations, with the

primary goal of removing them from the list of threatened and endangered

species. The difference between down- and delisting is based on the number of

viable populations, number of years, and the number of caves that meet the

recovery criteria. 

Downlisting and delisting for both species of Kauai cave arthropods may

be considered when the following critiera are met:

1. Downlisting Criteria

Downlisting to threatened may be considered for both species when nine

viable populations (populations contain representatives of all generations, sexes,

and age classes over a sustained period of time) of each species, spread across the

known range, are shown to be: (a) self-sustaining; (b) stable or increasing; (c)

protected from non-native/predatory species, human visitation to caves, biocontrol agents, pesticides, development or other damaging land uses; and (d) with

the habitat being used in a fashion consistent with conservation, all as evidenced

by monitoring over a 10-year period. 

2. Delisting Criteria

Delisting of both species may be considered when 12 viable populations,

of each species, spread across the known range, are shown to be: (a) selfsustaining; (b) stable or increasing; (c) protected from non-native/predatory

species, human visitation to caves, bio-control agents, pesticides, development or

other damaging land uses; and (d) with the habitat being used in a fashion

consistent with conservation, all as evidenced by monitoring over a 20-year
34

period (which is expected to assist in determining if the number of populations

identified for down- and de-listing are adequate). 

A 20-year monitoring period was determined to be necessary because land

development is slated to occur, during the first 10 years of monitoring, on lands

over areas that are known or suspected to contain caves that may support the

Kauai cave arthropods. These activities may cause significant changes in cave

environments and cause fluctuations in these species’ populations. An additional

period of at least 10 years following development will be needed to ensure that

the cave arthropods, which have probable low fecundity, are stable, and that these

species are responding appropriately to natural events that may be affecting their

population levels. Also, a post-delisting monitoring plan and agreement to

continue post-delisting monitoring must be in place and ready for implementation

at the time of delisting. Monitoring populations following delisting will verify

the ongoing recovery and conservation of the species and provide a means of

assessing the continuing effectiveness of management actions.

The number of caves needed to down-list and de-list both species is based

on the best available information, including: the nine caves that have been located

to date that are known to presently or historically support Kauai cave arthropods;

and the presence of land formations, such as lava rock out-croppings, that indicate

the potential presence of additional caves that may be suitable. These areas were

identified in the critical habitat rule for these species (U.S. Fish and Wildlife

Service 2003), and will be investigated for the presence of suitable habitat and

cave arthropods, as funds become available. Also, the number of caves with

viable populations, spread across the known range, represents what is necessary

to protect against stochastic events such as flooding, cave-ins, release of

contaminants, hurricanes that remove above ground vegetation, and disease. The

number of caves with viable populations, spread across the known range, also

provide for opportunities of genetic exchange (possibly through translocation),

resulting in the maintenance of genetic integrity for both species. In addition,

since the wolf spider relies on the amphipod population for food, the number of

caves with viable populations of amphipods, spread across the known range,

provides for the ability of the spider to move from areas of low populations of

amphipods to ones that can support predation. 
35

It must be emphasized that the cave wolf spider is reliably known from

only a single cave and appears to have recently disappeared or greatly declined

from a previously occupied cave. Downlisting criteria may not be met unless

additional caves are discovered and found to contain significant population units

of the cave wolf spider, and the above recovery criteria achieved in those caves.

B. NARRATIVE OUTLINE OF RECOVERY ACTIONS

1. Protect known populations of the Kauai cave wolf spider and cave

amphipod and their subterranean systems from human-caused destruction

or degradation.

1.1 Protect the cave interior and cave arthropods from uncontrolled 

human entry. 

Human entry and use of caves threaten the survival of cavedwelling arthropods both by intentional impacts such as vandalism

and collecting, as well as by unintentional impacts such as

trampling of arthropods and their food resources and introduction

of toxic materials (e.g., smoke, batteries). Caves with populations

of these arthropods should be closed to prevent unauthorized

and/or uncontrolled human access. Whenever possible, a locking

gate should be installed that employs durable materials that are not

easily dismantled, while providing access to authorized persons to

allow monitoring of the status of the arthropods and their habitat. 

Cave closure and access issues need to be developed with the

support of local landowners, appropriate State agencies, and

Hawaiian groups (e.g., burial councils). 

1.2 Protect/enhance overlying plant communities. 

Overlying perennial native plant communities should be protected

from loss, and enhanced. Overlying plant communities primarily

made up of non-natives should be removed and native plant

communities restored using plants known to serve as food sources

for the cave arthropods. Partnerships should be formed with

private land owners and other State and/or Federal agencies such

as the State Department of Land and Natural Resources and the
36

Federal Natural Resources Conservation Service to provide

restoration of non-native plant communities and maintenance of

perrenial native plant communities overlying caves. 

1.2.1 Develop and implement a fire control plan for surface

habitats. 

In addition to their protection from loss, whenever

appropriate, these overlying habitats should be protected

from wildfire which kills perennial vegetation and often

results in burn areas being taken over by inappropriate

vegetation communities (e.g., grass lands). The restoration

of appropriate vegetation communities (see Action 2.1

below) as well as working with landowners to develop a

fire plan for their land should be encouraged and supported.

1.3 Prevent the introduction of non-native predators and competitors

and carry out management actions that eliminate or reduce the

presence of non-native predators and competitors. 

During monitoring and other authorized visits, potentially harmful,

non-native species should be removed. This is particularly

pertinent for species such as the invasive brown violin spider, little

brown scorpion, centipedes, or large cockroaches, all of which are

non-native, generalist predators/foragers. If further research

suggests the control of such organisms can be accomplished

through habitat management such as reducing air movement and/or

increasing humidity levels, then these manipulations should be

incorporated into the management goals (see Actions 2.2 and 3.4

below).

1.4 Prevent the introduction of inappropriate bio-control organisms or

bio-pesticides throughout the State of Hawaii. 

The intentional release of bio-control organisms or bio-pesticides

has a long history of negative effects on the endemic Hawaiian

biota. While bio-control agents may provide great hope for the

protection of the State=s economy and the integrity of its native

ecosystems, all proposed bio-control agents, both new
37

introductions as well as re-introductions, should be carefully

considered and researched under section 7 of the Endangered

Species Act with U.S. Department of Agriculture to ensure they

pose no threat to native species, including the unique Hawaiian

cave fauna.

1.5 Prevent contamination of the cave from human-associated

activities such as runoff and soil percolation of pollutants or other

harmful chemicals including harmful pesticides. 

Inappropriate and/or overuse of chemical herbicides, insecticides,

and fungicides can have devastating effects on species living in

subterranean habitats (soils, caves, and mesocaverns). Heavy use

of such chemicals should be avoided above and adjacent to known

caves or mesocavern-containing habitats unless they are shown to

be safe (e.g., rapidly breakdown to inert components or are shown

to have no effect on non-target organisms). Limited use of

chemicals known to be safe may be permitted. Use of Asafe@

pesticides should only be used sparingly above or adjacent to

known cave-bearing rock and a limited-use buffer area should be

established around such areas.

2. Improve or enhance the habitat of occupied caves or caves previously

occupied through protection of above-cave habitats and implementation of

landscaping actions that are likely to increase subterranean food resources.

2.1 Manage surface vegetation that will provide root systems for

herbivorous and detritivorous cavernicoles with an abundant and

sustainable food resource.

Caves are typically regarded as being food-limited and recent work

conducted in one of the Koloa caves supports this. Possibly the

most important management activity for the recovery of these

species is to manage the overlying habitat to encourage the growth

of appropriate plants through weed control,

outplanting/landscaping, and irrigation-the roots will penetrate into

the cave and provide a source of fresh vegetation and detritus for

the cave amphipods. Increases in the amphipod population or
38

other cave-inhabiting detritivores should result in increases in prey

for these spiders. To the extent possible, efforts should be made to

outplant native and indigenous, nontoxic plants to enhance

subterranean habitats for native cave-dwelling species. Non-native

plants are known to provide food for the Kauai cave amphipod and

can be used if the situation dictates such an action. As has

occurred in some of the regularly monitored caves, pretreated

detrital material may be placed in such caves to help supplement

food reserves and to help maintain healthy populations of cave

amphipods until appropriate overlying vegetation can be planted

and become established, providing a long-term food supply to the

cave. Establishment of healthy plant root systems is already

known to be a valid management tool, but research should be

conducted to determine the best species of plants to use (e.g., plant

preferences, plant performance) (see Action 3.2 below). 

2.2 Maintain consistent high humidity within the Dark Zone and

increasing relative humidity within Stagnant Air Zones .

Terrestrial cave-dwelling organisms are largely restricted to cave

environments with high relative humidity. Evidence to support

this habitat criteria for the Kauai cave amphipod has been provided

by Miura and Howarth (1978). Increasing the relative, ambient

humidity is largely dependent upon reducing air velocity through

the cave, but adequate soil moisture is also important. As such,

caves that lack or have low amounts of air movement and occur in

areas where rain, or other sources of moisture help maintain a high

relative humidity, provide the best habitat for cave-dwelling

species. Cave humidity can be elevated by: (a) restricting air-flow

into and within the cave or passage way, and (b) adequately

irrigating the surface habitat to ensure an appropriate level of soil

saturation. Restricting air movement in caves to elevate ambient

humidity levels has not been conducted for the purpose of habitat

management for cavernicoles (cave dwellers) and should be

attempted cautiously to determine if it has value as a management

tool (see Action 3.4 below). Irrigation of above-cave habitats has

not been conducted for the benefit of cave habitats, but it has likely
39

contributed to improved habitat quality of Kiahuna Mauka Cave

and By-Pass Cave. Not only would appropriate irrigation of

surface habitats make cave climate more accommodating for these

arthropods, but it would also ensure that the overlying vegetation

community will remain healthy and minimize fire risk to the plant

community.

3. Conduct research to address essential conservation needs for the species.

3.1 Conduct non-invasive, non-damaging mark-recapture studies to

determine local population sizes and/or movement.

Conducting mark-recapture studies is essential for the estimation

of population sizes of any species. To date, no such studies have

been undertaken with Hawaiian cave animals, and have rarely

been undertaken with other cave-dwelling animals occurring

elsewhere. Developing non-damaging methods of marking these

arthropods would allow biologists to obtain needed information

on the population size of these species. Results from such a study

could result in the reevaluation of conservation actions and might

lead to reassessing our recovery criteria. In addition, successful

mark-recapture studies could provide more information on the life

history of these arthropods, specifically, provide some idea of

home range and longevity.

3.2 Determine the most beneficial and appropriate plants to be used for

habitat enhancement.

Numerous native or ornamental plants could be utilized for habitat

enhancement over cave/mesocavern habitats. However, certain

species are known to be particularly important with regard to

providing nutrient input into Hawaiian cave systems. The native

ohia tree (Metrosideros polymorpha) has roots known to be

important food sources for a number of endemic cave-dwelling

species on the island of Hawaii (Howarth 1981). Another endemic

plant, maiapilo (Capparis sandwichiana) is suspected of being an

important food resource in caves located in drier climates

(Howarth 1981). Both of these plants have large roots that often
40

enter caves and grow for extensive distances along the cave floor

where they are fed upon by herbivorous and detritivorous

cavernicoles. These plants and others should be tested to

determine how they perform in the Koloa District in order to refine

restoration and recovery actions for caves in these areas. 

3.3 Develop and utilize non-invasive molecular techniques to

determine the status of populations (not to be conducted with the

wolf spider until additional, healthy populations are discovered). 

It is not known if the separate population units of the cave

amphipod represent isolated populations or races, or if they should

be considered a single, panmictic population (random or nonselective mating within a breeding population) which exhibits

regular gene-flow between population units. Developing

molecular techniques to address this question is an important

research need that could affect the recovery criteria for the cave

amphipod. Information obtained from such molecular studies

would be important not only for management of the cave

amphipod, including reevaluation of the recovery criteria, but

would provide information on the extent and connectivity of cave

systems in the Koloa District. This information would have

important implications for the Kauai cave wolf spider, which

appears to be far more restricted in its current distribution. Given

the limited number of cave wolf spiders and their restricted range,

it is not currently advisable to conduct such studies with this

species. Any proposal to conduct such work with the wolf spider

should be carefully evaluated by qualified biologists.

3.4 Conduct studies to determine if manipulation of cave climate can

be used to improve habitat for the endangered cave arthropods

and/or control non-native species.

High ambient humidity is known to be an important habitat

parameter for cave-dwelling animals and has been shown to play a

role in the distribution of the Kauai cave amphipod (Miura and

Howarth 1978). Taking steps to increase cavern humidity is a

recommended management activity (see Action 2.2 above) that
41

should be conducted and its effectiveness should be determined. 

Observations in the Kauai caves suggests that harmful, non-native

species (e.g., brown violin spider) are not as abundant in areas

where ambient humidity is high. Should additional observations

and/or controlled experiments confirm the suitability of Ahumidity

regulation,@ then managing caves to increase the internal ambient

humidity could be a valuable management tool for increasing

population numbers of endangered cave-dwelling species and/or

reducing threats associated with nonnative predators/competitors.

3.5 Conduct surveys for additional occupied caves or restorable cave

systems.

Given the limited number of cave systems from which the cave

wolf spider and amphipod are currently known, finding more

occupied caves will be necessary if the Kauai cave dwelling

arthropods are to be down- or delisted. If additional occupied

caves are not discovered, increased emphasis should be placed on

protecting and restoring caves that have good potential for

supporting populations of one or both of these arthropods in the

future.

3.6 Continue the current monitoring regime (biannual or more

frequent) to determine population trends in caves and assess

recovery actions.

Biological surveys that result in verified records are the only

reliable means to determine the presence of a species and to

monitor population trends over time (Bogan et al. 1988). 

Standardized surveying and monitoring techniques should be

developed to continue the monitoring of known occupied caves

and caves that were previously occupied. While the current

monitoring activities do not provide sound population estimates,

they do provide some measure of population health within these

caves. Monitoring will be necessary to determine whether the

cave arthropods populations remain stable over time. This

monitoring should occur at least biannually so any drop in

population numbers can be quickly identified and management
42

actions taken. Each cave arthropod population identified by

completed surveys should be monitored at least biannually to

establish information on population trends and possible threats. In

addition, continued monitoring will be particularly important as

recovery activities are implemented, providing some measure of

success or failure of the management activities and allowing for

the implementation of adaptive management.

3.7 Conduct feasibility studies for the translocation of Kauai cave wolf

spiders and amphipods to unoccupied caves.

Given the current, known distribution of the both Kauai cave wolf

spider and Kauai cave amphipod, it will not be possible to achieve

the outlined downlisting or delisting criteria for the wolf spider,

and the delisting criteria for the amphipod, unless additional

occupied caves are discovered or spider populations become

established in currently unoccupied caves. It is possible that wolf

spiders and amphipods will disperse into known caves once

recovery actions are implemented. However, should the wolf

spider and amphipod remain absent from caves where conditions

appear to be optimal, biologists should consider the feasibility of

establishing new populations in such cave systems via

translocation. This is not a conservation activity that has received

attention and should be pursued only after serious consideration

involving a number of qualified biologists (e.g, those with

expertise with cavernofauna and/or with carrying out

translocations). 

 

3.8 Evaluate research results and implement adaptive management as

necessary.

The results of the above research actions should be evaluated and

incorporated into the management process and used in the

development of recovery objectives.

4. Conduct public outreach to facilitate better public understanding of and

support for conservation of these cave arthropods. 

The current plight of the obscure cave wolf spider and cave amphipod,

and the ecosystem upon which they depend, is not known to the residents
43

of Koloa and Poipu. Effective outreach should contribute to public

support for their conservation and serve to further inform local residents

and businesses regarding their conservation needs, the regulatory

requirements of the Endangered Species Act, and, very importantly,

available recovery tools such as Safe Harbor Agreements, Habitat

Conservation Plans, Federal funding through the Landowner Incentive

Program and Recovery Land Acquisition grant program, and voluntary

actions that the landowners can take to conserve the species.

5. Validate recovery objectives.

The scientific validity of the recovery objectives should be reviewed and

downlisting and delisting criteria should be revised, as appropriate, as

more information becomes available.

6. Develop and implement post-delisting monitoring plan as necessary. 

Prior to delisting of the Kauai cave wolf spider or cave amphipod, postdelisting monitoring plans should be in place and ready for 

implementation. Monitoring of populations following delisting will verify

the ongoing recovery and conservation of the species and provide a means

of assessing the continuing effectiveness of management actions.

Table 3 provides a cross-reference of recovery actions and listing factors.
44

Table 3. Cross-reference of recovery actions and listing factors for the Kauai

cave wolf spider and the Kauai cave amphipod.

LISTING 

FACTOR

THREAT STILL A 

THREAT

ACTION

NUMBERS

RECOVERY

CRITERIA

A Past land

modification due

to agricultural

practices

yes 1.2, 2.1, 2.2, 3.2 See pages 33-

34 for

downlisting

and delisting

criteria

A, D Development yes 1.2, 2.1, 2.2, 3.2

A Wildfire yes 1.2.1, 2.1, 2.2,

3.2

B Collection yes 1.1, 4

B Human visitation

to caves

yes 1.1, 4

C Nonnative

predators

yes 1.3, 2.2, 3.4

E Pesticide,

herbicide, and

fungicide use

yes 1.5

E Use of biocontrol

agents

yes 1.3, 1.4,1.5

E Susceptibility to

naturally

occurring events

such as storms or

earthquakes

yes 1.2, 3.1, 3.3,

3.4, 3.5, 3.7
45

III. IMPLEMENTATION SCHEDULE

The Implementation Schedule that follows outlines actions and estimated cost to downlist and/or

recover the Kauai cave arthropods. It is a guide for meeting the objectives

discussed in Part II of this plan. This schedule indicates action priority, action

numbers, action descriptions, duration of actions, the agencies/organizations

involved and/or responsible for committing funds and/or carrying out the

described activities, and lastly, provides estimated costs. When more than one

organization is listed as the responsible party, an asterisk is used to identify the

lead entity.

The actions identified in the implementation schedule, when

accomplished, should lead to a better understanding of the current distribution

and status of the Kauai cave arthropods, protect habitat for these species, stabilize

the existing populations, and allow for an increase in population sizes and

numbers. Monetary needs for all parties involved are identified to reach this

point, whenever feasible.

Priorities in Column 1 of the following implementation schedule are assigned

as follows:

Priority 1 An action that must be taken to prevent extinction or to prevent the

species from declining irreversibly.

Priority 2 An action that must be taken to prevent a significant decline in

species' population/habitat quality, or some other significant

negative impact short of extinction.

Priority 3 All other actions necessary to provide for full recovery of the

species.
46

Key to acronyms used in implementation schedule:

C An action that will be implemented on a routine basis once begun.

O An action that is currently being implemented and will continue

until action is no longer necessary. 

DLNR Hawaii Department of Land and Natural Resources, Division of

Forestry and Wildlife

ES U.S. Fish and Wildlife Service, Ecological Services, Pacific

Islands Fish and Wildlife Office, Honolulu, Hawaii 

PL Private Landowners

HDOA Hawaii Department of Agriculture

NRCS Natural Resource Conservation Service 

RD U.S. Geological Survey, Biological Resources Division 

BM Bishop Museum

USDA Department of Agriculture

PNI Participant not currently identified (academic, contractor, or other

institution)

H Indicates that some projects may have been completed or are in the

process of being implemented.

I Total probably represents low estimates since some actions, with

their associated funding, have not been completely implemented.
47

Implementation Schedule for the Draft Recovery Plan for the Kauai Cave ArthropodsPriority 

#

Task 

#

Action Description Action

Duration(years)

ResponsibleParty

Total CostThruYear 20($1,000's)

Costs Estimates ($Year01

Year02

Y0

1 1.1 Protect the cave interior and cave animals from

uncontrolled human entry.

O ES*, PL 120† 20 20 

1 1.2 Protect/enhance overlying plant communities. O ES*, PL, NRCS 780 100 100 

 1 1.2.1 Develop and implement fire control plan for

surface habitats.

O ES*, PL 500 60 100 

1 1.3 Prevent introduction of non-native predators

and competitors and carry out managementactions that eliminate or reduce the presence ofnon-native predators and competitors.

C ES 105† 8 8 

1 1.4 Prevent intentional introduction of bio-control

organisms and bio-pesticides

C ES 500 25 25 

1 1.5 Prevent contamination of the cave from

human-associated activities such as runoff andsoil percolation of pollutants or other harmfulchemicals including harmful pesticides.

C ES, PL* 260 10 20 

1 3.6 Continue current monitoring regime (biannual

or more frequent) to determine populationtrends in caves and assess recovery actions.

O ES 775 5 5 

1 3.8 Evaluate research results and implement

adaptive management as necessary.

C ES, PL* 200 10 10 
48

Implementation Schedule for the Draft Recovery Plan for the Kauai Cave ArthropodsPriority 

#

Task 

#

Action Description Action

Duration(years)

ResponsibleParty

Total CostThruYear 20($1,000's)

Costs Estimates ($Year01

Year02

Y0

2 2.1 Manage surface vegetation that will provide

root systems for herbivorous and detritivorouscavernicoles with an abundant and sustainablefood resource.

O ES*, PL 91 10 10 

2 2.2 Maintaining consistent high humidity within

the Dark Zone and increasing relative humiditywithin stagnant air zones.

O ES*, PL 44 5 5 

3 3.1 Conduct non-invasive, non-damaging markrecapture studies to determine local population

sizes and/or movement.

C ES, BM*, BRD,

PNI

500 40 40 

3 3.2 Determine the most beneficial and appropriate

plants to be used for habitat enhancement.

O ES*, BRD, PNI 340 60 60 

3 3.3 Develop and utilize non-invasive molecular

techniques to determine the status ofpopulations (not to be conducted with the wolfspider until additional, healthy populations arediscovered.

C PNI 700 100 100 

3 3.4 Conduct studies to determine if manipulation

of cave climate can be used to improve habitatfor the endangered cave animals and/or controlnon-native species.

O ES*, PNI 480 60 60 
49

Implementation Schedule for the Draft Recovery Plan for the Kauai Cave ArthropodsPriority 

#

Task 

#

Action Description Action

Duration(years)

ResponsibleParty

Total CostThruYear 20($1,000's)

Costs Estimates ($Year01

Year02

Y0

3 3.5 Conduct surveys for additional occupied caves

or restorable cave systems.

O ES, DLNR*,

PNI

204 12 12 

3 3.7 Conduct feasibility studies for the translocation

of wolf spiders and amphipods to unoccupiedcaves.

20 ES, BM*, PNI 700 100 100 

3 4 Conduct public outreach to facilitate better

public understanding of and support forconservation of the cave animals.

O ES*, PNI 110 10 10 

3 5 Validate recovery objectives. C ES 200 10 10 3 6 Develop and implement a post-delisting

monitoring plan as necessary. 

C ES 21 1 1 

TOTAL COST TO RECOVERY 6,630‡ 646‡ 696‡ 6
50

IV. REFERENCES

A. Literature Cited

Allen, J. 1997. Pre-contact landscape transformation and cultural change in

windward Oahu. Pp. 230-247. In: P.V. Kirch and T.L. Hunt (eds.). 

Historical Ecology in the Pacific Islands. Yale Univ. Press, New Haven,

Connecticut.

Athens, J.S. 1997. Hawaiian native lowland vegetation in prehistory. Pp. 248-

270. In: P.V. Kirch and T.L. Hunt (eds.). Historical Ecology in the Pacific

Islands. Yale Univ. Press, New Haven, Connecticut.

Ahearn, G.A. and F.G. Howarth. 1982. Physiology of cave arthropods in Hawaii.

Journal of Experimental Zoology 222: 227-238.

Barr, T.C. 1968. Cave ecology and evolution of troglobites. Evolutionary

Biology 2: 35-102.

Berger, A.J., S. Conant, F.J. Radovsky, D. Mueller-Dombois, and F.G. Howarth.

1981. Chapter 5, Introduction. Pp. 213-230. In: D. Mueller-Dombois,

K.W. Bridges, and H.L. Carson (eds.). Island Ecosystems: Biological

Organization in Selected Hawaiian Communities. Hutchinson Ross Pub.

Co., Stroudsburg, Pennsylvania.

Bogan, M.A., R.B. Finley, Jr., and S.J. Petersburg. 1988. The importance of

biological surveys in managing public lands in the western United States.

Pp. 254-261: in Management of amphibians, reptiles, and small mammals

in North America. USDA Gen. Tech. Report RM-166.

Bousfield, E.L. and F.G. Howarth. 1976. The cavernicolous fauna of Hawaiian

lava tubes, 8. terrestrial Amphipoda (Talitridae), including a new genus

and species with notes on its biology. Pacific Insects 17: 144-154.

Burney, D.A., S.L. Olson, L.P. Burney, H.F. James, W. Kikuchi, W.L. Wagner,

M. Burney, D. McCloskey, D. Kikuchi, F.V. Grady, R. Gage, and R.

Nishek. 2001. Fossil evidence for a diverse biota from Kauai and its

transformation since human arrival. Ecological Monographs 71(4): 615-

641.

Cole, R.F., A.C. Medeiros, L.L. Loope, and W.W. Zuehlke. 1992. Effects of the

Argentine ant on the arthropod fauna of Hawaiian high-elevation

shrubland. Ecology 73 (4): 1313-1322.
51

Cuddihy, L.W. and C.P. Stone. 1990. Alteration of the native Hawaiian

vegetation; effect of humans, their activities and introductions. 

Cooperative National Park Resources Studies Unit, Hawaii, 138 pp.

Culver, D.C. 1986. Cave faunas. Pp. 427-443. In: M.E. Soulé (ed.)

Conservation Biology: The Science of Scarcity and Diversity. Sinauer

Assoc., Inc., Sunderland, Massachusetts.

Culver, D.C. 1992. Cave faunas. Pp. 427-443. In: P. L. Fiedler and S. K. Jain

(eds.) Conservation Biology: The Theory and Practice of Nature

Conservation, Preservation, and Management. Chapman and Hall, New

York and London. 

Culver, D.C., L.L. Master, M.C. Christman, and H.H. Hobbs. 2000. Obligate

cave fauna of the 48 contiguous United States. Conservation Biology

14(2): 386-401.

Foelix, R.F. 1982. Biology of Spiders. Harvard Univ. Press, Cambridge. 306 pp.

Foote, D.E., E.L. Hill, S. Nakamura, and F. Stephens. 1972. Soil Survey of

Islands of Kauai, Oahu, Maui, Molokai, and Lanai, State of Hawaii. 

United States Department of Agriculture Soil Conservation Service and

the University of Hawaii Agricultural Experiment Station. 232 pp.

Gertsch, W.J. 1973. The cavernicolous fauna of Hawaiian lava tubes, 3. Araneae

(Spiders). Pacific Insects 15: 163-180.

Gilpin, M.E. and M.E. Soule. 1986. Minimum viable populations: processes of

species extinction. Pp 19-34. In: M.E. (Ed.). Conservation Biology: The

Science of Scarcity and Diversity. Sinauer Associates Inc., Sunderland,

Massachusetts.

Hadley, N.F., G.A. Ahearn, and F.G. Howarth. 1981. Water and metabolic

relations of cave-adapted and epigean lycosid spiders in Hawaii. Journal

of Arachnology 9: 215-222.

Hammatt, H.H. and M.J.F. Tomonari. 1978. Archaeological and Biological

Survey of the Proposed Kiahuna Golf Village Area, Koloa, Kona, Kauai

Island, Hawaii.

Hammatt, H.H., D. Borthwick, D. Shideler, and M. Stride. 1988. Archaeological

Inventory Survey of the Proposed Kukuiula Bay Planned Community,

Koloa, Kona, Kauai. Report prepared for R.M. Towill Corporation by

Cultural Surveys Hawaii, June 1988.
52

Hawaii State Division of Forestry and Wildlife. Hawaii Revised Statutes. 1995.

Section 195D-4. State of Hawaii. 34 pp.

Hobdy, R. 1993. LanaiBA Case Study: The Loss of Biodiversity on a Small

Island. Pacific Science 47 (3): 201-210.

HOSP. 1992. Golf Course Development in Hawaii: Impacts and Policy

Recommendations. Hawaii Office of State Planning. 110 pp.

Howarth, F.G. 1973. The cavernicolous fauna of Hawaiian lava tubes, 1.

Introduction. Pacific Insects 15: 139-151.

Howarth F.G. 1981. Community structure and nice differentiation in Hawaiian

lava tubes. Pp. 318-336. In: D. Mueller-Dombois, K.W. Bridges, and H.L.

Carson (eds.). Island Ecosystems: Biological Organization in Selected

Hawaiian Communities. Hutchinson Ross, Stroudsburg, Pennsylvania.

Howarth F.G. 1982. The conservation of cave invertebrates. Proceedings of the 1st

International Cave Management Symposium. Murray, Kentucky, 1981.

Howarth F.G. 1983. Ecology of cave arthropods. Annual Review of Entomology

28: 365-389.

Howarth, F.G. 1985. Impacts of alien land arthropods and mollusks on native

plants and animals in Hawaii. Pp. 149-179. In: C.P. Stone and J.M. Scott

(eds.). Hawaii’s Terrestrial Ecosystems: Preservation and Management.

Cooperative National Park Resources Studies Unit, University of Hawaii,

Honolulu, Hawaii.

Howarth F.G. 1991. Hawaiian cave faunas: macroevolution on young islands. Pp.

285-295. In: E.C. Dudley (ed.). The Unity of Evolutionary Biology.

Discorides Press, Portland, Oregon.

Howarth, F.G. and F. D. Stone 1990. Elevated carbon dioxide levels in Bayliss

Cave, Australia: implications for the evolution of obligate cave species. 

Pacific Science 44: 207-218.

Howarth F.G. and F.D. Stone. 1993. Conservation of Hawaii=s speleological

resources. Pp. 124-126. In: Proceedings of the 3rd International

Symposium on Vulcanospeleology. ABC Publishing, Vancouver,

Washington.

Howarth, F.G., W. McDowell, and J. Dockall. 2003. An assessment of the

biological importance and recommendations for management of caves
53

within the Kukuiula property, Koloa, Kauai. Prepared for Kukuiula

Development Company (Hawaii), LLC. Koloa, Hawaii. 22 pp.

Huppop, K. 1985. The role of metabolism in the evolution of cave animals. The

National Speliological Society Bulletin 47(2): 136-146.

IUCN. 1994. 1994 IUCN Red List of Threatened Animals. The World

Conservation Union, International Union for the Conservation of Nature,

Gland, Switzerland. 286 pp.

Kirch, P.V. 1982. The impact of the prehistoric Polynesians on the Hawaiian

ecosystem. Pacific Science, 36: 1-14.

Langenheim, V.A.M. and D.A. Clague. 1987. The Hawaiian-Emperor Volcanic

Chain, Part II. Stratigraphic framework of volcanic rocks of the Hawaiian

Islands. Pp. 55-84. In: R.W. Decker, T.L. Wright, and P.H. Stauffer (eds.).

Volcanism in Hawaii. U.S.G.S. Professional Paper 1350.

MacDonald, G.A., D.A. Davis, and D.C. Cox. 1960. Geology and Ground-water

Resources of the Island of Kauai, Hawaii. Hawaii Division of Hydrology

and the U.S. Geological Survey. 212 pp.

Miura, M.T. and F.G. Howarth.1978. Appendix III. Cave fauna survey. In: 220-

231. 

H.H. Hammatt and M.J.F. Tomonari Tuggle (eds.). Archaeological and Biological

Survey of the Proposed Kiahuna Golf Village Area, Koloa, Kona, Kauai

Island. Archaeological Research Center, Hawaii, Inc. for Moana Corp.

Lawai, Hawaii, September 1978. 

Nishida, G.M. (ed). 1992. Hawaiian Terrestrial Arthropod Checklist. Bishop

Museum Technical Report No. 1. Honolulu, Hawaii 262 pp.

Poulson, T.L. and W.B. White. 1969. The cave environment. Science 165: 971-

981.

Soule, M. 1983. What do we really know about extinction? Pp 111-124. In: C. M.

Schonewald-Cox, S. M.Chambers, B. MacBryde, and L. Thomas (eds.). 

A reference for managing wild animal and plant populations. 

Benjamin/Cummings Publishing Co., Inc., Menlo Park, California.

U.S. Fish and Wildlife Service. 1983. Endangered and threatened species listing

and recovery priority guidelines. Federal Register 48(184): 43098-43105.

U.S. Fish and Wildlife Service. 1994. Recovery Plan for Endangered Karst

Invertebrates (Travis and Williamson Counties, Texas). U.S. Fish and

Wildlife Service, Albuquerque, New Mexico.
54

U.S. Fish and Wildlife Service. 1997. Recovery Plan for the Lee County Cave 

Isopod (Lirceus usdagalun). U.S. Fish and Wildlife Service, Hadley,

Massachusetts.

U.S. Fish and Wildlife Service. 2000a. Endangered and Threatened Wildlife and

Plants: Final Rule to List Two Cave Animals from Kauai, Hawaii as

Endangered. Federal Register 65(10): 2348-2357.

U.S. Fish and Wildlife Service. 2000b. A Study of the Effects of Golf Course

Organophosphate and Carbamate Pesticides on Endangered, CaveDwelling Arthropods, Kauai, Hawaii. U.S. Fish & Wildlife Service,

Ecological Services, Honolulu, Hawaii.

U.S. Fish and Wildlife Service. 2003. Endangered and Threatened Wildlife and

Plants; Designation of Critical Habitat for the Kauai Cave Wolf Spider

and Kauai Cave Amphipod. Final Rule. Federal Register 68(68 ): 17430-

17470.

Wells, S.M., R.M. Pyle, and N.M. Collins. 1983. The IUCN Invertebrate Red

Data Book. IUCN, Gland, Switzerland. 632 pp.

B. In Litt. References

Asquith, A. U.S. Fish and Wildlife Service. 1994a. Memorandum of Kauai trip to

view spider and amphipod habitat. 2 pp.

Asquith, A. U.S. Fish and Wildlife Service. 1994b. Memorandum regarding

potential predators of Kauai cave arthropods. TELCON with Frank

Howarth, Bishop Museum. 1 pp.

Asquith, A. U.S. Fish and Wildlife Service. 1995. Memorandum to the files.

Asquith, A. U.S. Fish and Wildlife Service. 1999. Memorandum tot he files.

Hopper, D. H. U.S. Fish and Wildlife Service. 1999. Letter to Christa Russell,

Craig Rowland, Karen Rosa, Don Palawski, Kauai Team and Stephen

Miller about Kauai trip for 19-21 August 1999. 1 pp.

Howarth, F. 2001. Letter.

U.S. Fish and Wildlife Service. in Litt. 1995. Cooperative Agreement with

Alexander & Baldwin.

U.S. Fish and Wildlife Service. Unpublished data 1996.
55

U.S. Fish and Wildlife Service. Unpublished data 1997.

U.S. Fish and Wildlife Service. Unpublished data 1998.

U.S. Fish and Wildlife Service. Unpublished data 1999.

U.S. Fish and Wildlife Service. Unpublished data 2000.

U.S. Fish and Wildlife Service. Unpublished data 2001.

U.S. Fish and Wildlife Service. Unpublished data 2002.

U.S. Fish and Wildlife Service. Unpublished data 2003.

U.S. Fish and Wildlife Service. Unpublished data 2004.

C. Personal Communication

Howarth, F.G. 2003, Bishop Museum.