bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Melbourne Edge Test contrast sensitivity measures in the visually impaired
Authors: Wolffsohn James S. , Eperjesi Frank , Napper Genevieve
Published: June 2005

Aim:  Contrast sensitivity (CS) provides important information on visual function. This study aimed to assess differences in clinical expediency of the CS increment‐matched new back‐lit and original paper versions of the Melbourne Edge Test (MET) to determine the CS of the visually impaired.

Methods:  The back‐lit and paper MET were administered to 75 visually impaired subjects (28–97 years). Two versions of the back‐lit MET acetates were used to match the CS increments with the paper‐based MET. Measures of CS were repeated after 30 min and again in the presence of a focal light source directed onto the MET. Visual acuity was measured with a Bailey–Lovie chart and subjects rated how much difficulty they had with face and vehicle recognition.

Results:  The back‐lit MET gave a significantly higher CS than the paper‐based version (14.2 ± 4.1 dB vs 11.3 ± 4.3 dB, p < 0.001). A significantly higher reading resulted with repetition of the paper‐based MET (by 1.0 ± 1.7 dB, p < 0.001), but this was not evident with the back‐lit MET (by 0.1 ± 1.4 dB, p = 0.53). The MET readings were increased by a focal light source, in both the back‐lit (by 0.3 ± 0.81, p < 0.01) and paper‐based (1.2 ± 1.7, p < 0.001) versions. CS as measured by the back‐lit and paper‐based versions of the MET was significantly correlated to patients’ perceived ability to recognise faces (r = 0.71, r = 0.85 respectively; p < 0.001) and vehicles (r = 0.67, r = 0.82 respectively; p < 0.001), and with distance visual acuity (both r = −0.64; p < 0.001).

Conclusions:  The CS increment‐matched back‐lit MET gives higher CS values than the old paper‐based test by approximately 3 dB and is more repeatable and less affected by external light sources. Clinically, the MET score provides information on patient difficulties with visual tasks, such as recognising faces.
The morphometric analysis of the central retinal artery
Authors: Kocabiyik Necdet , Yalcin Bulent , Ozan Hasan
Published: June 2005

In this study, we aimed to investigate some features of the central retinal artery (CRA), which supplies the internal aspect of the retina. The CRA is the main vessel supplying blood to the retina. The origin, course and penetration point of the optic nerve by the CRA were studied in 30 human orbits. We compared the right sides to the left sides on the basis of gender in order to statistically analyse the relation between them. The CRA arose directly from the ophthalmic artery in 28 specimens. In two specimens, however, it arose in common with the medial posterior ciliary artery. When we observed the penetration point (site) of the CRA into the optic nerve, in 28 of 30 (93.3%) cases, the artery entered the nerve from the lower medial aspect and in two (6.7%) cases from the upper lateral aspect. The CRA penetrated the optic nerve between 6.4 and 15.2 mm behind the eyeball and reached the eyeball through the centre of the optic nerve. Because of the small diameter of the artery, it has a high risk of getting damaged during a surgical approach to the orbit. Therefore the anatomical relationships of this artery must be well known.
The need for optometric investigation in suspected Meares–Irlen syndrome or visual stress
Authors: Evans Bruce J. W.
Published: June 2005

Meares–Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual distortions when viewing text. The symptoms are alleviated with individually prescribed coloured filters, such as precision tinted lenses. Meares–Irlen syndrome, and the related condition of visual stress, are likely to result from hyperexcitability of the visual cortex, which can also occur in migraine. The symptoms of Meares–Irlen syndrome and visual stress are non‐specific and the condition needs to be differentially diagnosed from other optometric conditions, such as refractive error, binocular vision anomalies, and accommodative anomalies. Three case reports are described of patients who consulted the author with suspected Meares–Irlen syndrome but were found to have other causes for their symptoms: posterior sub‐capsular cataract, high uncorrected astigmatism, and decompensated convergence weakness exophoria. These cases highlight the need for professional eye care for people with suspected Meares–Irlen syndrome. Although this advice is stressed in literature on the well‐established MRC/Wilkins Intuitive Colorimeter system, it is not always stressed in literature about other systems. This may be a cause for concern.
Eye fixation scanpaths of younger and older drivers in a hazard perception task
Authors: Underwood Geoffrey , Phelps Nicola , Wright Chloe , Van Loon Editha , Galpin Adam
Published: June 2005

Our previous research has shown that observing patterns of eye fixations is a successful method of establishing differences in underlying cognitive processes between groups of drivers. Eye movements recorded from drivers in a laboratory while they watch film clips recorded from a driver's perspective can be used to identify scanpaths and search patterns that reveal ability differences. In the present study 12 older subjects (60–75 years) and 12 younger subjects (30–45 years) watched clips for potential hazards such as other road users appearing on an intersecting trajectory. Acuity and visual field differences between the two groups were eliminated through screening, so that only age‐related differences would emerge. Eye fixations were analysed on a frame‐by‐frame basis to generate sequences of codes representing the location and object of the viewer's interest, before and during the appearance of a hazard. These codes were analysed for the existence of two fixation scanpaths using Markov Matrices. Unique scanpaths were identified for each group of drivers before and during the hazard. Evidence from the inspection of different objects and from the spread of the search indicated that both groups of driver were sensitive to attentional capture by the appearance of the hazard. Detection of the hazards – both speed and accuracy – was similar for older and younger drivers, although the older drivers perceived the films as being more hazardous in general. There is little evidence in this study of an age‐related decline in the search of the scene when detecting hazards.
Characteristics of pupil responses during far‐to‐near and near‐to‐far accommodation
Authors: Kasthurirangan Sanjeev , Glasser Adrian
Published: June 2005

The static and dynamic aspects of the pupil response associated with various amplitudes of far‐to‐near (accommodation) and near‐to‐far (disaccommodation) focusing responses were evaluated in this study. Dynamic refractive and pupillary changes were measured simultaneously during focusing responses to targets at real distances in 12 young (23–26 years) emmetropic subjects. The targets were presented alternately at far (6 m) and at one of six near positions from 1 D (1 m) to 6 D (16.7 cm) in 1 D steps. The latency, magnitude and peak velocity of pupil changes associated with accommodation and disaccommodation responses were calculated. The latency of refractive changes was shorter than that of pupillary changes. In general, the pupil constricted with accommodation and started dilating while accommodation was still maintained, resulting in reduced pupil dilation with disaccommodation. The magnitude of the pupil response increased linearly with that of accommodation and disaccommodation. The amount of pupil change per dioptre of refractive change was invariant with various amplitudes of refractive change. The peak velocity of pupil constriction was greater than that of pupil dilation for corresponding amplitudes. The pupil response is more closely associated with accommodation than with disaccommodation.
Aberrations and myopia
Authors: Charman W. N.
Published: June 2005

It has been suggested that high levels of axial aberration or specific patterns of peripheral refraction could play a role in myopia development. Possible mechanisms involving high levels of retinal image blur caused by axial aberrations include form deprivation through poor retinal image quality in distance vision, enhanced accommodative lags favouring compensatory eye growth, and an absence of adequate directional cues to guide emmetropization. In addition, in initially emmetropic eyes, hyperopia in the retinal periphery may result in local compensatory eye growth, which induces axial myopia. Evidence in support of these ideas is reviewed and it is concluded that, for any fixed pupil diameter, evidence for higher levels of axial aberration in myopes in comparison with other refractive groups is weak, making involvement of axial aberrations in myopization through image degradation at the fovea unlikely. If, however, some potential myopes had unusually large pupil diameters, their effective aberration levels and associated retinal blur would be larger than those of the rest of the population. There is stronger evidence in favour of differences in patterns of peripheral refraction in both potential and existing myopes, with myopes tending to show relative hyperopia in the periphery. These differences appear to be related to a more prolate eyeball shape. Longitudinal studies are required to confirm whether the retinal defocus associated with the peripheral hyperopia can cause patterns of eyeball growth which lead to axial myopia.
Downward deviation of progressive addition lenses in a myopia control trial
Authors: Hasebe Satoshi , Nakatsuka Chiaki , Hamasaki Ichiro , Ohtsuki Hiroshi
Published: June 2005

Purpose:  To clarify how the downward deviation of progressive addition lenses (PALs) reduces their near‐addition effect in schoolchildren participating in a myopia control trial.

Methods:  Among 95 schoolchildren wearing PALs for 6 months (age range: 6–12 years; refractive error range: −6.00 to −1.25 D), facial images were captured with a digital still camera placed 60 cm in front of the eyes while he or she was looking ahead with natural head posture. The vertical deviations of PALs from their ideal position (mm) were evaluated by analysing these images.

Results:  The mean (±SD) downward deviations of PALs for the right and left eyes were 3.7 ± 2.3 and 3.7 ± 2.0 mm, respectively, and the largest downward deviation was 10.2 mm. For simulations using the average downward deviation, the near‐addition effect of PALs was reduced to 30 and 63% of the expected value at the 10° and 20° downward eye positions, respectively.

Conclusions:  The downward deviation of PALs is a significant factor in reducing their therapeutic effect for near‐addition. To ensure the proper alignment of PALs in children, the conventional spectacle‐frame‐fitting procedure is not sufficient, and repeated confirmation using a testing method similar to that used in this study is required.
Refractive error and ocular biometry in Jordanian adults
Authors: Mallen Edward A. H. , Gammoh Yazan , Al‐Bdour Muawyah , Sayegh Fouad N.
Published: June 2005

The aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17–40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand‐Seiko GR‐3100K closed‐view infrared autorefractor. Ocular component measurements were made using A‐scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than −0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and −0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age.
Optometric and ophthalmic contact in elderly hip fracture patients with visual impairment*
Authors: Cox A. , Blaikie A. , MacEwen C. J. , Jones D. , Thompson K. , Holding D. , Sharma T. , Miller S. , Dobson S. , Sanders R.
Published: June 2005

Aim:  To describe previous contact with optometry and ophthalmic services in a group of elderly patients with and without visual impairment (VI) who had fallen and sustained a fractured neck of femur.

Method:  A cross sectional study of 537 patients aged 65 and over who had undergone hip fracture surgery in four Scottish centres (Glasgow, Ayr, Dundee and Fife). All patients had an in‐depth optometric history, ophthalmic history and examination.

Results:  Three hundred and ninety‐three (79%) patients reported optometric contact in the 3 years preceding surgery and 107 (21%) patients had not seen an optometrist for more than 3 years. In the latter group, 64 had VI, which was due to uncorrected refractive error in 17 (27%) and untreated cataract in 20 (31%). VI (best binocular visual acuity of 6/18 or less) was found in 239 (46%) patients. A past ophthalmic history was present in 257 (50%) patients. Only 39 (16%) patients with VI were under ophthalmic care at the time of the study.

Conclusions:  There was significantly poor optometric and ophthalmic contact in patients who had VI and had fallen and sustained hip fracture. A proportion of the VI (66%) was due to uncorrected refractive error and untreated cataract. Public health providers should be made aware of the fact that current optometric and ophthalmic care pathways are not accessed by this group of elderly patients with VI and at risk of falling.
Edge Influence on Forest Structure and Composition in Fragmented Landscapes
Authors: HARPER KAREN A. , MACDONALD S. ELLEN , BURTON PHILIP J. , CHEN JIQUAN , BROSOFSKE KIMBERLEY D. , SAUNDERS SARI C. , EUSKIRCHEN EUGÉNIE S. , ROBERTS DAR , JAITEH MALANDING S. , ESSEEN PER‐ANDERS
Published: June 2005

Abstract:  Although forest edges have been studied extensively as an important consequence of fragmentation, a unifying theory of edge influence has yet to be developed. Our objective was to take steps toward the development of such a theory by (1) synthesizing the current knowledge of patterns of forest structure and composition at anthropogenically created forest edges, (2) developing hypotheses about the magnitude and distance of edge influence that consider the ecological processes influencing these patterns, and (3) identifying needs for future research. We compiled data from 44 published studies on edge influence on forest structure and composition in boreal, temperate, and tropical forests. Abiotic and biotic gradients near created forest edges generate a set of primary responses to edge creation. Indirect effects from these primary responses and the original edge gradient perpetuate edge influence, leading to secondary responses. Further changes in vegetation affect the edge environment, resulting in ongoing edge dynamics. We suggest that the magnitude and distance of edge influence are a direct function of the contrast in structure and composition between adjacent communities on either side of the edge. Local factors such as climate, edge characteristics, stand attributes, and biotic factors affect patch contrast. Regional factors define the context within which to assess the ecological significance of edge influence (the degree to which the edge habitat differs from interior forest habitat). Our hypotheses will help predict edge influence on structure and composition in forested ecosystems, an important consideration for conservation. For future research on forest edges in fragmented landscapes, we encourage the testing of our hypotheses, the use of standardized methodology, complete descriptions of study sites, studies on other types of edges, synthesis of edge influence on different components of the ecosystem, and investigations of edges in a landscape context.
Reduced Diversity and Complexity in the Leaf‐Litter Ant Assemblage of Colombian Coffee Plantations
Authors: ARMBRECHT INGE , RIVERA LEONARDO , PERFECTO IVETTE
Published: June 2005

Abstract:  Coffee agroecosystems have recently undergone a dramatic intensification in Colombia, a megadiverse country, especially in terms of the nature of shade cover. We tested for changes in the composition, ecological associations, and diversity of ants (Hymenoptera: Formicidae) along a gradient of intensification of coffee production in the Colombian Andes. We surveyed 16 farms in two regions, classified into four management types: (1) forest (no agriculture), (2) organic polygeneric shaded coffee, (3) monogeneric shaded coffee, and (4) sun coffee (unshaded). Forty sampling units (20 1‐m2 plots on the ground and 20 coffee bushes) were established at each farm between 2001 and 2002. We sampled with a mini‐winkler litter extraction technique and through visual searching. Organic polygeneric shaded‐coffee plantations contained significantly higher ant species richness, and their ant assemblages resembled the forest patches more than any other management type. The number of statistically significant associations among ant species dropped with production intensification, as did the number of ant species involved in such associations. The network of ant associations in shaded systems transformed into an extremely simplified network in sun coffee, with a few dominant ants extending almost entirely throughout the crop. Intensification of coffee agriculture not only caused loss of litter ant species (especially forest species) but also a reduction in the complexity of the ant assemblage in the leaf litter of this agroecosystem.
Effects of Life‐History Traits on Responses of Plant Species to Forest Fragmentation
Authors: KOLB ANNETTE , DIEKMANN MARTIN
Published: June 2005

Abstract:  Knowing the general principles of plant‐environment relationships is required to be able to predict changes in species occurrence and abundance in changing landscapes. Because habitat fragmentation may affect the dispersal, establishment, and persistence of species in various ways, we expected associations between species life‐history traits related to these processes and their responses to fragmentation. We tested (1) whether groups of plant species with specific biological attributes are especially affected by forest fragmentation and (2) whether regionally rare species are more negatively affected than more common species. We surveyed 145 deciduous forest patches in northwestern Germany for the presence of a large set of forest plant species. For each of 82 species, we collected data on eight life‐history traits and estimated species' responses to decreased patch size and increased distance to other occupied forest patches. We classified species into two emergent groups that differed strongly with respect to most considered life‐history traits. The group of species that was more negatively affected by isolation mostly consisted of clonal forest specialist species characterized by few and heavy diaspores, lack of dispersal structures, small size, short‐lived seeds, and insect pollination. There was no effect of patch area. Univariate analyses revealed (marginally) significant relationships between species' responses to isolation and diaspore number and mass, plant height, and habitat preference and between responses to patch area and seed‐bank longevity, plant height, and habitat preference. Regional frequency of occurrence was not correlated to species' responses to fragmentation and did not differ between the two emergent groups. Rare species, however, were smaller and produced fewer and shorter‐lived diaspores than common species. Forest fragmentation may thus threaten species differently, depending on their specific biological characteristics. Approaches based on life‐history traits potentially allow prediction of species' responses to habitat fragmentation and may therefore aid in the assessment of the endangerment of plant species and ultimately in the conservation of biological diversity.
Wildlife Loss through Domestication: the Case of Endangered Key Deer
Authors: PETERSON M. NILS , LOPEZ ROEL R. , LAURENT EDWARD J. , FRANK PHILIP A. , SILVY NOVA J. , LIU JIANGUO
Published: June 2005

Abstract:  Wildlife extinction represents the ultimate failure of wildlife conservation. It has many causes, some of them natural, but is increasingly tied to anthropogenic factors. Wildlife loss via domestication, however, is rarely considered. We evaluated the potential for inadvertent domestication of wildlife by determining the effect of feeding and watering on Key deer (Odocoileus virginianus clavium) density, group size, and distribution. Key deer sightings were significantly higher in areas (42 ha) surrounding the households that provided food and water (0.18 deer/m;n =8) than in randomly selected areas (0.03 deer/m;t =3.82, 14  df, p =0.002). Average distance to a household providing food and water decreased logistically as group size increased, and large groups (>2 individuals each) were observed more frequently in areas where food and water were provided (27.5%) than in the randomly selected areas (7.5%). The incidence of large groups outside feeding areas (7.5%), however, was similar to the incidence of large groups during early urbanization (5.1%; 1968–1973). Our results suggest illegal feeding caused changes in density, group size, and distribution indicative of domestication. Because fresh water and food were primary selective pressures for Key deer before illegal feeding and watering, genetic changes may occur in the future. For those who value “wildness” in wildlife, domestication of wildlife species is a serious problem that must be addressed.
Historical Evidence of Widespread Chytrid Infection in North American Amphibian Populations
Authors: OUELLET MARTIN , MIKAELIAN IGOR , PAULI BRUCE D. , RODRIGUE JEAN , GREEN DAVID M.
Published: June 2005

Abstract:  Emerging infectious diseases may be contributing to the global decline of amphibian populations. In particular, chytridiomycosis, a cutaneous fungal infection of amphibians caused by the chytrid Batrachochytrium dendrobatidis, gained attention in the 1990s as an apparently new pathogen. This fungus has been implicated as the causative agent of widespread mortalities among wild amphibians in geographically disparate parts of the world. To investigate the global distribution, historical occurrence, and infectiousness of this pathogen, we examined 3371 postmetamorphic and adult amphibians collected between 1895 and 2001 from 25 countries for the presence of chytrid fungi in the epidermis. Cutaneous chytrid infection was diagnosed in 383 of 2931 (13.1%) specimens of 12 common amphibian species from five Canadian provinces and seven American states, including 30 of 69 locations examined in the St. Lawrence River Valley of Québec. Chytrids were observed in 7.0% (46/655) of the adults collected in the 1960s, the earliest cases being two green frogs ( Rana clamitans) collected in 1961 from Saint‐Pierre‐de‐Wakefield, Québec. In recent studies, morbidity and mortality attributable to chytridiomycosis were not observed in infected amphibians from Québec despite a 17.8% (302/1698) prevalence of chytrid infection during the period 1990–2001. The prevalence of infection during this latter period was not statistically different when compared with the period 1960–1969. Epidermal chytrid infections were not observed in 440 amphibians examined from 23 other countries. In light of the fact that infection by B. dendrobatidis is widely distributed and apparently enzootic in seemingly healthy amphibians from eastern North America, lethal outbreaks of chytridiomycosis among amphibian populations appear to have complex causes and may be the result of underlying predisposing factors.
Accounting for Uncertainty in Making Species Protection Decisions
Authors: PRATO TONY
Published: June 2005

Abstract: Uncertainty gives rise to two decision errors in implementing the U.S. Endangered Species Act: listing species that are not in danger of extinction and delisting species that are in danger of extinction. I evaluated four methods (minimum standard, precautionary principle, minimax regret criterion, adaptive management) for deciding whether to list or delist a species when there is uncertainty about how those decisions are likely to influence survival of the species. A safe minimum standard criterion preserves some minimum amount or safe standard (population) of a species unless maintaining that amount generates unacceptable social cost. The precautionary principle favors not delisting a species when there is insufficient evidence on the efficacy of state management plans for protecting them. A minimax regret criterion selects the delisting decision that minimizes the maximum loss likely to occur under alternative ecosystem states. When the cost of making a correct decision is less than the cost of making an incorrect decision, the minimax regret criteria indicates that delisting is the optimal decision. Active adaptive management employs statistically valid experiments to test hypotheses about the likely impacts of delisting decisions. Safe minimum standard and minimax regret criterion are not compatible with the U.S. Endangered Species Act. The precautionary principle comes closest to describing how federal agencies make delisting decisions. Active adaptive management is scientifically superior to the other methods but is costly and time consuming and may not be compatible with the U.S. National Environmental Policy Act.
Interacting Effects of Landownership, Land Use, and Endangered Species on Conservation of Southwestern U.S. Rangelands
Authors: SAYRE NATHAN F.
Published: June 2005

Abstract:  The contemporary southwestern United States is characterized by fire‐adapted ecosystems; large numbers of federally listed threatened and endangered species; a patchwork of federal, state, and private landownership; and a long history of livestock grazing as the predominant land use. I compared eight sites in southern Arizona and New Mexico to assess the interacting effects of these characteristics on conservation practices and outcomes. There was widespread interest and private‐sector leadership in restoring fire to southwestern rangelands, and there is a shortage of predictive scientific knowledge about the effects of fire and livestock grazing on threatened and endangered species. It was easier to restore fire to lands that were either privately owned or not grazed, in part because of obstacles created by threatened and endangered species on grazed public lands. Collaborative management facilitated conservation practices and outcomes, and periodic removal of livestock may be necessary for conservation, but permanent livestock exclusion may be counterproductive because of interactions with land‐use and landownership patterns.
Effects of Karst Forest Degradation on Pulmonate and Prosobranch Land Snail Communities in Sabah, Malaysian Borneo
Authors: SCHILTHUIZEN MENNO , LIEW THOR‐SENG , ELAHAN BERJAYA BIN , LACKMAN‐ANCRENAZ ISABELLE
Published: June 2005

Abstract: Limestone (karst) outcrops in Southeast Asia are rich in land snails. Certain groups of land snails, in particular Prosobranchia species, are restricted to limestone and show a high degree of short‐range endemism. Karst habitats are, however, seriously degraded by quarrying, logging, agriculture, and burning. The effect of these disturbances on land snail fauna is unknown, so we studied paired primary and secondary forest localities on six separate limestone hills in Sabah, Malaysian Borneo. Land snails were sampled with a standard protocol and identified to species level. More than 16,000 individuals, belonging to 74 species, were recorded. In most sites, snail diversities did not differ between disturbed and undisturbed plots. However, pulmonate snails were significantly more abundant at disturbed localities than prosobranch snails, whereas abundances for both groups were similar at undisturbed sites. Because Prosobranchia contain many site‐endemic species, our findings suggest that continued exposure to these disturbances will eventually lead to extinctions in this group.
Effectiveness of Environmental Surrogates for the Selection of Conservation Area Networks
Authors: SARKAR SAHOTRA , JUSTUS JAMES , FULLER TREVON , KELLEY CHRIS , GARSON JUSTIN , MAYFIELD MICHAEL
Published: June 2005

Abstract:  Rapid biodiversity assessment and conservation planning require the use of easily quantified and estimated surrogates for biodiversity. Using data sets from Québec and Queensland, we applied four methods to assess the extent to which environmental surrogates can represent biodiversity components: (1) surrogacy graphs; (2) marginal representation plots; (3) Hamming distance function; and (4) Syrjala statistical test for spatial congruence. For Québec we used 719 faunal and floral species as biodiversity components, and for Queensland we used 2348 plant species. We used four climatic parameter types (annual mean temperature, minimum temperature during the coldest quarter, maximum temperature during the hottest quarter, and annual precipitation), along with slope, elevation, aspect, and soil types, as environmental surrogates. To study the effect of scale, we analyzed the data at seven spatial scales ranging from 0.01° to 0.10° longitude and latitude. At targeted representations of 10% for environmental surrogates and biodiversity components, all four methods indicated that using a full set of environmental surrogates systematically provided better results than selecting areas at random, usually ensuring that ≥90% of the biodiversity components achieved the 10% targets at scales coarser than 0.02°. The performance of surrogates improved with coarser spatial resolutions. Thus, environmental surrogate sets are useful tools for biodiversity conservation planning. A recommended protocol for the use of such surrogates consists of randomly selecting a set of areas for which distributional data are available, identifying an optimal surrogate set based on these areas, and subsequently prioritizing places for conservation based on the optimal surrogate set.
Rural and Suburban Sprawl in the U.S. Midwest from 1940 to 2000 and Its Relation to Forest Fragmentation
Authors: RADELOFF VOLKER C. , HAMMER ROGER B. , STEWART SUSAN I.
Published: June 2005

Abstract: Housing growth and its environmental effects pose major conservation challenges. We sought to (1) quantify spatial and temporal patterns of housing growth across the U.S. Midwest from 1940–2000, (2) identify ecoregions strongly affected by housing growth, (3) assess the extent to which forests occur near housing, and (4) relate housing to forest fragmentation. We used data from the 2000 U.S. Census to derive fine‐scale backcasts of decadal housing density. Housing data were integrated with a 30‐m resolution U.S. Geological Survey land cover classification. The number of housing units in the Midwest grew by 146% between 1940 and 2000. Spatially, housing growth was particularly strong at the fringe of metropolitan areas (suburban sprawl) and in nonmetropolitan areas (rural sprawl) that are rich in natural amenities such as lakes and forests. The medium‐density housing (4–32 housing units/km2) category increased most in area. Temporally, suburban housing growth was especially high in the post‐World War II decades. Rural sprawl was highest in the 1970s and 1990s. The majority of midwestern forests either contained or were near housing. Only 14.8% of the region's forests were in partial block groups with no housing. Housing density was negatively correlated with the amount of interior forest. The widespread and pervasive nature of sprawl shown by our data is cause for conservation concern. Suburban sprawl has major environmental impacts on comparatively small areas because of the high number of housing units involved. In contrast, rural sprawl affects larger areas but with less intensity because associated housing densities are lower. The environmental effects per house, however, are likely higher in the case of rural sprawl because it occurs in less‐altered areas. Conservation efforts will need to address both types of sprawl to be successful.
Patch Size and Connectivity Thresholds for Butterfly Habitat Restoration
Authors: SCHULTZ CHERYL B. , CRONE ELIZABETH E.
Published: June 2005

Abstract:  Recovery of endangered species in highly fragmented habitats often requires habitat restoration. Selection of restoration sites typically involves too many options and too much uncertainty to reach a decision based on existing reserve design methods. The Fender's blue butterfly ( Icaricia icarioides fenderi) survives in small, isolated patches of remnant prairie in Oregon's Willamette Valley—a habitat for which <0.5% of the original remains. Recovery of this species will require considerable habitat restoration. We investigated the potential of biologically based rules of thumb and more complex models to serve as tools in making land acquisitions. Based on Fender's blue dispersal behavior and demography, we have estimated that restored patches should be <1 km from existing habitat and at least 2 ha. We compared these rules to the results of two modeling approaches: an incidence function model and a spatially explicit simulation of demography and dispersal behavior. Not surprisingly, the simple rules and complex models all conclude that large (>2 ha) connected (<1 km) patches have the highest restoration value. The dispersal model, however, suggests that small, connected patches have more restoration value than large, isolated patches, whereas the incidence function model suggests that size and connectivity are equally important. These differences stem from model assumptions. We used incidence functions to predict long‐term, stochastic, steady‐state conditions and dispersal simulations to predict short‐term (25‐year) colonization dynamics. To apply our results in the context of selecting restoration sites on the ground, we recommend selecting nearby sites when short‐term colonization dynamics are expected to be an important aspect of a species' biology.
Shade‐Coffee Plantations as Refuges for Tropical Wild Orchids in Central Veracruz, Mexico
Authors: SOLIS‐MONTERO LISLIE , FLORES‐PALACIOS ALEJANDRO , CRUZ‐ANGÓN ANDREA
Published: June 2005

Abstract: In central Veracruz, Mexico, coffee plantations have replaced large areas of lower montane cloud forest. Shade‐coffee plantations with high levels of structural diversity provide refuge for forest‐dependent biota (e.g., birds and insects). Orchids typical of natural forest may also be found in the canopy of shade‐coffee agroecosystems. It is not known, however, whether these are relicts from the original forest vegetation or if the plantations themselves provide the necessary conditions to support a self‐sustained orchid population. We studied the population structure of the epiphytic orchidsJacquiniella teretifolia(Sw.) Britton & Willson, Scaphyglottis livida(Lindl.) Schltr., andMaxillaria densaLindl. in a shade‐coffee plantation (commercial polyculture) in central Veracruz. We also studied the previously undescribed reproductive biology of the latter two species. Our results show that the three orchid species had high population densities (>800 plants/ha). In our study site, 50% to 68% of the orchid plants of the target species were young individuals (less than five shoots). Reproductive structures were present in 80% of individuals larger than 30 shoots in the three species.M. densais self‐incompatible, and the fruit set obtained from cross pollination (42.7%) was higher than that obtained from natural pollination (18.2%), suggesting that this species could be pollinator limited.S. lividais autocompatible, not autogamous, and was not pollinator limited. Our results show that the coffee plantation had abundant orchid populations with log‐normal size/age structures. Two of the target species, M. densaandS. livida, depend on pollinators to reproduce. It is clear that pollinators that allow orchids to set a high proportion of fruits persist in shade‐coffee plantations. Coffee plantations may not replace the original conditions of a forest, but it is possible that these and other orchid species survive and reproduce in coffee plantations that provide appropriate microclimate conditions for the plants, including pollinators.
Experimental Analysis of the Impact of Foxes on Freshwater Turtle Populations
Authors: SPENCER RICKY‐JOHN , THOMPSON MICHAEL B.
Published: June 2005

Abstract:  Common demographic parameters such as survival and fecundity are regularly estimated in freshwater turtles, but large‐scale manipulative and comparative experiments are rare. The resilience of a population to stage‐specific predation is dependent on density‐dependent inversity or compensation. Some species are also more susceptible to predation because of their life‐history strategies. Nest predation by introduced red foxes ( Vulpes vulpes) on Australian freshwater turtles is a major source of mortality, but its full impact has yet to be evaluated. Freshwater turtles are long lived, and a population decline resulting from nest predation by foxes may take a long time to become evident. We evaluated the impact of foxes on the population growth and patterns of survival of two widely distributed Australian freshwater turtles in the Murray River, where nest predation rates have previously been reported at above 95%. We estimated densities and survivorship of Emydura macquarii and Chelodina expansa from the nest to adult stage. We then conducted a fox removal program (before‐after control‐impact design) to determine the impact of foxes on populations of these species. We found a contrast in life‐history strategies between the two sympatric species. C. expansa was five times less abundant than E. macquarii. A type III survivorship curve described the life history of E. macquarii because nest predation and adult survival rates were >0.9. Densities of C. expansa nests were low and situated away from shore. Consequently, nest predation rates were half those of E. macquarii. Projection matrices predicted that E. macquarii populations may be declining slowly but are likely to respond to changes in adult survival, which has the greatest elasticity value. Foxes destroyed a proportion of nesting adult females each year; however, there appears to be no density‐dependent compensation in adult survival, and foxes potentially regulate these populations. E. macquarii populations had low productivity and relied on a standing crop of turtles for population maintenance, whereas C. expansa had relatively more juveniles in the population and was less reliant on adult survival. Despite its vulnerable status, C. expansa is relatively more stable than E. macquarii, primarily because there were proportionally more juveniles in the population. Management options focusing on reducing adult mortality in both species will be most effective.
Conservation and the Myth of Consensus
Authors: PETERSON M. NILS , PETERSON MARKUS J. , PETERSON TARLA RAI
Published: June 2005

Abstract: Environmental policy makers are embracing consensus‐based approaches to environmental decision making in an attempt to enhance public participation in conservation and facilitate the potentially incompatible goals of environmental protection and economic growth. Although such approaches may produce positive results in immediate spatial and temporal contexts and under some forms of governance, their overuse has potentially dangerous implications for conservation within many democratic societies. We suggest that environmental decision making rooted in consensus theory leads to the dilution of socially powerful conservation metaphors and legitimizes current power relationships rooted in unsustainable social constructions of reality. We also suggest an argumentative model of environmental decision making rooted in ecology will facilitate progressive environmental policy by placing the environmental agenda on firmer epistemological ground and legitimizing challenges to current power hegemonies that dictate unsustainable practices.
Importance of Attitudinal Differences among Artisanal Fishers toward Co‐Management and Conservation of Marine Resources
Authors: GELCICH STEFAN , EDWARDS‐JONES GARETH , KAISER MICHEL J.
Published: June 2005

Abstract:  The Chilean government has introduced a policy that gives formal property rights over defined areas of seabed to organized groups of artisanal fishers with the goal of achieving sustainable exploitation of natural resources. We assessed differences in the attitudes of participating artisanal fishers toward this form of management to understand their importance in the design and implementation of fisheries management. We used questionnaires and participatory rural appraisal techniques to survey members of six fishing management committees. Fishers' attitudes varied significantly among syndicates in three main domains: attitudes toward the environment, unresolved aspects behind the management area policy, and perceived benefits derived from adoption of the policy. These differences indicated the existence of distinct world views that structure fishers' behavior toward the marine environment and its management. In addition, the responses made by fishers correlated best with the degree of off‐sector pluriactivity and their dependence on diving as a source of income. This suggested that a livelihood approach to the development of Chilean artisanal fisheries that considers the multiple economic niches of the fishers will be most effective in the implementation of dual conservation/management measures.
Diversity Relationships among Taxonomic Groups in Recovering and Restored Forests
Authors: ANAND MADHUR , LAURENCE SOPHIE , RAYFIELD BRONWYN
Published: June 2005

Abstract:  Our objective was to reexamine the definition and use of surrogates in biodiversity studies of disturbed ecological communities. To this end, we examined diversity and community structure in recovering (pollution damaged) and restored (via liming, fertilizing, seeding, and planting) forests in the Great Lakes‐St. Lawrence zone near Sudbury, Ontario, Canada. The relationships among taxonomic groups were determined using correlations between Shannon diversity and species richness. We used correspondence analysis to quantify the contribution of taxonomic groups to diversity and community structure. We detected useful surrogates in the naturally recovering forests but not in restored forests. In the former, vascular plant diversity was significantly correlated with nonvascular plant diversity and reflected community structure in the total plant community. Our results suggest that it may be important to restore and conserve diversity relationships rather than simply diversity levels because the relationships may be better indicators of ecosystem health or function.
Use of Simulated Annealing for Identifying Essential Fish Habitat in a Multispecies Context
Authors: COOK ROSAMONDE R. , AUSTER PETER J.
Published: June 2005

Abstract: Essential fish habitat (EFH) is defined under U.S. federal law, which mandates its protection. Current single‐species approaches to identifying EFH for suites of managed species have resulted in areas designated for protection that are so large that protecting fish habitat has been difficult in the context of fishery management. We evaluated the potential for simulated annealing, a type of mathematical optimization, as a tool for simultaneously identifying EFH for multiple species in four ecological regions of the eastern continental shelf of the United States. Data were obtained from a shelf‐wide trawl survey with site‐specific abundance information spanning 37 years. The data were averaged within units of a sampling grid with 10‐minute squares. We used computer software with an objective function that includes a term for weighting the boundary length of selected sampling units and thereby identifies solutions that meet specific targets for representation under varying degrees of spatial aggregation. We defined representation as a percentage of the cumulative sampled abundance of individual species and examined the effects of these target values and spatial constraints on total (sea‐surface) area and boundary length of solution sets. We also evaluated the algorithm for its ability to select areas where juveniles occurred at high densities as a proxy for habitat value. Annealing solutions covered less total area than would the combined habitats of individual species that capture the same proportion of population abundance. For most species in most solutions, high‐density areas were selected in higher proportions to their relative abundance in a region and solutions contained less total habitat area and smaller boundary lengths. Additionally, sampling units were distributed among two or more discrete localities versus a single location for the same target level of representation. We suggest that simulated annealing is a viable tool for EFH planning with the potential for identifying more spatially conservative habitat areas for protection than a single‐species approach.
How Many Species Are There in Brazil?
Authors: LEWINSOHN THOMAS M. , PRADO PAULO INÁCIO
Published: June 2005

Abstract:  We produced estimates of the total number of species currently known and the total numbers predicted to occur in Brazil. Lists of species recorded in Brazil were obtained from specialists and the literature. For taxa lacking information on total known species, we produced estimates based on bootstrap resampling from a set of 87 taxa with checklists for Brazil and the world. The estimated proportion of Brazilian species was 9.5% of the world total (95% CI, 8.5 to 11.5%). From this we estimated a known Brazilian biota of 170,000 to 210,000 species. We used a similar procedure to estimate Brazil's total biota—known plus undiscovered. Based on 17 relatively well‐known taxa, the average Brazilian share in the world's biota was estimated at 13.1% (CI 10.0 to 17.6%). Accordingly we estimated the country's total biota at 1.8 million species (CI 1.4 to 2.4 million). Given that the Neotropics is the least‐studied major region of the world, these figures are still likely to be underestimates and hence may be taken as a lower bound of the actual proportion of the world's species that occur in Brazil. Scientists, policy makers, and citizens will find these numbers useful in appreciating the magnitude of the tasks involved in surveying, describing, and conserving the country's biota. The numbers also bring proposals and priorities into a more realistic perspective.
Conservation of Brazilian Amphibians
Authors: SILVANO DÉBORA L. , SEGALLA MAGNO V.
Published: June 2005

Abstract:  Brazil is the world leader in amphibian diversity, with 765 species, most of which have been described in the last 40 years. The Brazilian Official List of Threatened Species and the results of a workshop for the Global Amphibian Assessment indicate that 26 species are threatened. The majority of these occur in the Atlantic Forest, one of the world's biodiversity hotspots. The main threat to amphibians is the destruction of their habitats through deforestation, conversion into agricultural land, mining, wildfires, and infrastructure development and urbanization. In Brazil little is known about other causes of amphibian decline observed worldwide, such as pesticides, infectious diseases, climate change, invasive species, or wildlife trade. Brazilian conservation policies include such important legal instruments as the Official List of Threatened Species and the selection of priority areas for conservation measures in all of Brazil's major biomes. Although there is little information on geographic distributions and the natural history and ecology of the large majority of the currently recognized species, a number of important regional studies for amphibian conservation are under way. New species are discovered each year.