bluuebunny/crossref_metadata_2025 huggingface dataset:
Lemurs and the Regeneration of Dry Deciduous Forest in Madagascar
Authors: Ganzhorn Jörg U. , Fietz Joanna , Rakotovao Edmond , Schwab Dorothea , Zinner Dietmar
Published: March 2003

Abstract: We sought to assess the role of lemurs for seed dispersal in the dry deciduous forest of western Madagascar and the possible consequences of the demise of lemurs for forest regeneration. Forest regeneration was studied in eight plots in two large blocks of primary forest and in seven fragments of primary forest (1 plot per fragment). In 4 of the 15 study plots, the abundance of saplings was negatively and significantly correlated (p < 0.05) with the abundance of mature individuals of the same tree species. In another 10 study plots there were negative correlations, although these were not significant on the community level. Second‐order statistics were significant with p < 0.001 and indicated that seed dispersal away from the parent trees was important for successful establishment of saplings. Apart from possibly the bush pig (Potamochoerus larvatus), only one vertebrate species of the dry forest, the brown lemur (Eulemur fulvus), ingested seeds> 11 mm long and passed them through its digestive tract unharmed. These results for lemurs were based on direct observations and fecal analyses. To evaluate the role of E. fulvus, we compared regeneration in forest plots with and without E. fulvus. In forest fragments without E. fulvus, fewer lemur‐dispersed tree species regenerated than would be expected based on the presence of mature tree species that are lemur‐dispersed (p < 0.05). No such effect was seen in primary forests with E. fulvus or for trees whose seeds can also be dispersed by other vertebrates. Thus, regeneration of the dry deciduous forest of western Madagascar with the complete set of primary forest tree species seems to depend upon the presence of E. fulvus.
Why Economics Matters for Endangered Species Protection
Authors: Shogren Jason F. , Tschirhart John , Anderson Terry , Ando Amy Whritenour , Beissinger Steven R. , Brookshire David , Brown Gardner M. , Coursey Don , Innes Robert , Meyer Stephen M. , Polasky Stephan
Published: March 2003

Abstract: We offer three reasons why economics matters more to species protection than many people think and what this implies for the ongoing debate over the reauthorization of the Endangered Species Act of 1973. Economics matters because (1) human behavior generally, and economic parameters in particular, help determine the degree of risk to a species; (2) in a world of scarce resources, the opportunity cost of species protection—the costs of reduced resources for other worthwhile causes—must be taken into account in decision making; and (3) economic incentives are critical in shaping human behavior, and consequently the recovery of species. Endangered species protection that explicitly addresses these basic principles can avoid wasting valuable resources that yield no gain in species protection.
Novel Tools to Reduce Seabird Bycatch in Coastal Gillnet Fisheries
Authors: Melvin Edward F. , Parrish Julia K. , Conquest Loveday L.
Published: March 2003

Abstract: We examined several strategies to reduce seabird bycatch, primarily of Common Murres (Uria aalge) and Rhinoceros Auklets (Cerorhinca monocerata), in a coastal salmon drift gillnet fishery in Puget Sound, Washington, U.S.A. Our goal was to significantly reduce seabird bycatch without a concomitant reduction in target catch or an increase in the bycatch of any other species. We compared fish catch and seabird bycatch in nets modified to include visual alerts (highly visible netting in the upper net) or acoustic alerts (pingers) to traditional monofilament nets set throughout the normal fishing hours over a 5‐week fishing season. Catch and bycatch varied significantly as a function of gear. Relative to monofilament controls, murres responded to both visual and acoustic alerts; auklets and sockeye salmon responded to deeper visual alerts only. Seabird abundance varied across multiple temporal scales: interannually, within fishing season, and over the day. At the interannual level, seabird entanglement was linked to regional abundance on the fishing grounds, a pattern that broke down at the local level. Within season, sockeye and murre abundance were negatively correlated, suggesting that if fishery openings were scheduled on peak abundance of the target species, seabird bycatch would be significantly reduced as a function of increased target fishing efficiency. Finally, both sockeye catch and auklet entanglement were highest at dawn, whereas murre entanglement was high at both dawn and dusk. Our results identify three complementary tools to reduce seabird bycatch in the Puget Sound drift gillnet fishery—gear modifications, abundance‐based fishery openings, and time‐of‐day restrictions—for a possible reduction in seabird bycatch of up to 70–75% without a significant reduction in target fishing efficiency. Although these tools are based on local conditions and will thus vary among years and locations, all might be exportable to other coastal gillnet fisheries worldwide.
Effective Population Size and Maintenance of Genetic Diversity in Captive‐Bred Populations of a Lake Victoria Cichlid
Authors: Fiumera A. C. , Parker P. G. , Fuerst P. A.
Published: March 2003

Abstract:We used microsatellite DNA markers to investigate the maintenance of genetic diversity within and between samples of subpopulations (spanning five captive‐bred generations) of the haplochromine cichlidPrognathochromis perrieri. The subpopulations are maintained as part of the Lake Victoria Cichlid species survival plan. Changes in the frequencies of 24 alleles, over four polymorphic loci, were used to estimate effective population size (  Ne   ). Point estimates ofNeranged from 2.5 to 7.7 individuals and were significantly smaller than the actual census size (  Nobs  ) for all subpopulations (32–243 individuals per generation), with the corresponding conservativeNe  /  Nobsratios ranging from 0.01 to 0.12. Approximately 19% of the initial alleles were lost within the first four generations of captive breeding. Between‐generation comparisons of expected heterozygosity showed significant losses ranging from 6% to 12% per generation. Seven private alleles were observed in the last sampled generation of four subpopulations, and analysis of population structure byFSTindicated that approximately 33% of the total genetic diversity is maintained between the subpopulations from different institutions. To reduce the loss of genetic variation, we recommend that offspring production be equalized by periodically removing dominant males, which will encourage reproduction by additional males. Consideration should also be given to encouraging more institutions to maintain populations, because a significant fraction of the genetic variation exists as among‐population differences resulting from random differentiation among subpopulations.
Bird Communities of Prairie Uplands and Wetlands in Relation to Farming Practices in Saskatchewan
Authors: Shutler Dave , Mullie Adele , Clark Robert G.
Published: March 2003

Abstract:Modern farm practices can vary in their emphasis on tillage versus chemicals to control weeds, and researchers know little about which emphasis has greater ecological benefits. We compared avifaunas of uplands and wetlands in four treatments: conventional farms, conservation farms (contrasting those that minimized frequency of tillage [minimum tillage] with those that eliminated chemical inputs [organic]), and restored or natural (wild) sites in Saskatchewan, Canada. Of 37 different upland bird species encountered during surveys, one made greater use of farms, four made greater use of wild sites, and the remaining species showed no preference. When all upland species were combined, higher relative abundance occurred on wild than on farm sites, and on minimum tillage than on conventional farms. Wild upland sites also had more species than did conventional farms. Of 79 different species encountered during surveys of wetlands and their margins, most had similar encounter probabilities among treatments, although seven were more common on either organic farms or wild sites. Higher relative abundances were documented in wetland habitat of wild sites and organic farms than of minimum tillage or conventional farms. Wetlands of wild sites had more species than did minimum tillage or conventional farms. Overall, in terms of both avifaunal density and diversity, small treatment effects could be ascribed to differences between conventional and conservation farms, whereas larger effects were due to differences between farms and wild sites. Wetlands were heavily used by birds in all treatments, suggesting high conservation priority regardless of context.
Population Persistence in Florida Torreya: Comparing Modeled Projections of a Declining Coniferous Tree
Authors: Schwartz Mark W. , Hermann Sharon M. , Van Mantgem Phillip J.
Published: March 2003

Abstract: The Florida torreya (  Torreya taxifolia) is a coniferous tree endemic to a 35‐km stretch of bluffs and ravines along the east side of the Apalachicola River in northern Florida and southern Georgia. This formerly locally abundant tree has declined as a result of disease during the 1950s and is on the U.S. endangered species list. With no seed production in the wild, this species is headed toward extinction. We conducted a survey on roughly 200 trees from 1988 to 1996 and used these data to estimate the likelihood of population persistence during the next several decades. We compared a stage‐class transition matrix model ( RAMAS) and an individual‐based stochastic model ( TORSIM) of growth and mortality to project future populations. Given the current lack of seed production in the wild, all models predict extinction. The question of concern is the imminence of this predicted extinction. Differing predicted times to extinction would suggest different immediate management recommendations. Both models predicted an over 90% likelihood of persistence during the next 50 years. Predictions differed in that the transition matrix model was less optimistic than the individual‐based model regarding persistence. Model sensitivity analysis showed that the results were robust to significant decreases in growth and sprouting probabilities. Submodels identified different persistence likelihoods in different populations. Nonetheless, unless management of the population can facilitate maturation and seed production, extinction of this species in the wild is inevitable.
Inherent Rarity in Community Restoration
Authors: Maina Godfrey G. , Howe Henry F.
Published: March 2003

Abstract: We explore the implications of an often overlooked fact in community restoration: most species, in real or synthetic communities, are infrequent or rare, a phenomenon we call “inherent rarity.” Whether from long‐term interactions of many factors affecting birth, death, and establishment within natural communities, or from short‐term interactions of recently created communities, species abundance distributions are roughly lognormal or even more attenuated. The greater the predisturbance species diversity of remnants or the planting diversity of restorations, and the smaller the area of a habitat patch, the more likely a large proportion of species will exist in populations so small that they are acutely or chronically vulnerable to local extinction. We suggest that habitat fragmentation will inevitably favor plants and animals that are highly mobile, early successional species, including many exotic weeds among plants, or species that are historically organized as metapopulations that happen to be common enough to function as such. We further explore rationales for countering the effects of inherent rarity, including connectivity from buffers, corridors, and stepping stones, and dominance suppression from seasonally appropriate mowing, grazing, or fire.
Conservation of the Toromiro Tree: Case Study in the Management of a Plant Extinct in the Wild
Authors: Maunder Mike , Culham Alastair , Alden Bjorn , Zizka Georg , Orliac Cathérine , Lobin Wolfram , Bordeu Alberto , Ramirez Jose M. , Glissmann‐Gough Sabine
Published: March 2003

Abstract: We reviewed the history and conservation of Sophora toromiro, a species that has been extinct in the wild since 1960 but has survived as scattered individuals in botanic gardens and private collections. The short‐term conservation of S. toromiro is dependent on the management of surviving ex situ stocks. This is being achieved through international collaboration by a working group established to coordinate the conservation management of the species. Molecular evidence indicates that the species retains greater genetic variability than expected. The greatest amount of genetic variability was located in specimens outside botanic garden collections. No unmodified natural habitat survives on Rapa Nui ( Easter Island); so opportunities to establish a viable wild population are limited. Evidence from past reintroductions indicates that the best short‐term opportunity for the species is through conventional horticultural management in botanic gardens and traditional farm plots on Rapa Nui. Some extinct‐in‐the‐wild taxa (sensu World Conservation Union 1994), such as the Toromiro, retain genetic variability, and appropriate reintroduction sites exist. These taxa represent valid priorities for conservation management.
Long‐Term Effects of Logging on African Primate Communities: a 28‐Year Comparison From Kibale National Park, Uganda
Authors: Chapman Colin A. , Balcomb Sophia R. , Gillespie Thomas R. , Skorupa Joseph P. , Struhsaker Thomas T.
Published: March 2003

Abstract: If logging is to be compatible with primate conservation, primate populations must be expected to recover from the disturbance and eventually return to their former densities. Surveys conducted over 28 years were used to quantify the long‐term effects of both low‐ and high‐intensity selective logging on the density of the five common primates in Kibale National Park, Uganda. The most dramatic exception to the expectation that primate populations will recover following logging was that group densities of Cercopithecus mitis and C. ascanius in the heavily logged area continued to decline decades after logging. Procolobus tephrosceles populations were recovering in the heavily logged areas, but the rate of increase appeared to be slow (0.005 groups/km2 per year). Colobus guereza appeared to do well in some disturbed habitats and were found at higher group densities in the logged areas than in the unlogged area. There was no evidence of an increase in Lophocebus albigena group density in the heavily logged area since the time of logging, and there was a tendency for its population to be lower in heavily logged areas than in lightly logged areas. In contrast to the findings from the heavily logged area, none of the species were found at a lower group density in the lightly logged area than in the unlogged area, and group densities in this area were not changing at a statistically significant rate. The results of our study suggest that, in this region, low‐intensity selective logging could be one component of conservation plans for primates; high‐intensity logging, however, which is typical of most logging operations throughout Africa, is incompatible with primate conservation.
Evaluating Great Smoky Mountains National Park as a Population Source for the Wood Thrush
Authors: Simons Theodore R. , Farnsworth George L. , Shriner Susan A.
Published: March 2003

Abstract:The prevailing fragmentation paradigm predicts that large, intact forests are acting as population sources for Neotropical migrant landbirds. We used the Wood Thrush (  Hylocichla mustelina) as a model for evaluating the role Great Smoky Mountains National Park (the largest national park in the eastern United States) may play in maintaining regional songbird populations. We estimated the annual productivity of Wood Thrushes in the park by combining observations on the birds' distribution, abundance, and productivity with estimates of habitat availability. We estimated a breeding population of approximately 10,000 nesting pairs using habitat models developed from over 2500 point‐count censuses conducted across the park. Data from 426 nests monitored from 1992 to 1997 produced a daily nest survival rate of 0.96. We estimated an annual fecundity of 2.76 fledglings per breeding pair, based on a model that incorporated the re‐nesting behavior of Wood Thrushes. Results indicate that the park is producing approximately 3000 surplus female young each year. Daily nest survival rates were below those reported in other studies of Wood Thrushes in large forest tracts. The relatively high productivity of 3.31 nestlings per successful nest suggests that, in the absence of predation, the park provides high‐quality nesting habitat for Wood Thrushes, but that it may also support a more diverse and abundant predator community than more disturbed or less contiguous sites. The difficulties of estimating the size of continental breeding bird populations make assessing the significance of the park within a regional landscape context problematic, but our estimates suggest that, although the park is functioning as a substantial population source on a local scale, its potential to sustain regional or continental Wood Thrush populations is limited. Our findings suggest that species such as the Wood Thrush are capable of moderate levels of surplus productivity in high‐quality habitat, but that extensive areas of suitable habitat outside protected areas and other public lands will be required to sustain continental breeding populations.
Wetland Loss and Biodiversity Conservation
Authors: Gibbs James P.
Published: March 2003

Abstract:Most species of wetland‐dependent organisms live in multiple local populations sustained through occasional migration. Retention of minimum wetland densities in human‐dominated landscapes is fundamental to conserving these organisms. An analysis of wetland mosaics was performed for two regions of the northeastern United States to assess the degree to which historical wetland loss alters the metrics of wetland mosaics and to assess potential future effects mediated by differently structured wetland regulations. These analyses indicated that profound reductions in wetland density and proximity are associated with increased human populations and that protections for all wetlands>1 acre (0.4 ha) are likely required to retain wetland densities minimally sufficient to sustain the wetland biota.
Why Poor Logging Practices Persist in the Tropics
Authors: Putz Francis E. , Dykstra Dennis P. , Heinrich Rudolf
Published: March 2003

Abstract:Despite abundant evidence that both the environmental damage and the financial costs of logging can be reduced substantially by training workers, pre‐planning skid trails, practicing directional felling, and carrying out a variety of other well‐known forestry practices, destructive logging is still common in the tropics. Based on our collective experience with loggers in tropical forests, we discuss seven possible reasons for this seemingly irrational behavior. The principal reason poor logging practices persist is apparently that the widely heralded cost savings associated with reduced‐impact logging relative to unplanned logging by untrained crews may not be realized under some conditions. In particular, where compliance with logging guidelines restricts access to steep slopes or prohibits ground‐based timber yarding on wet ground, reduced‐impact logging may be synonymous with reduced‐income logging. Given that under such conditions loggers may not adopt reduced‐impact logging methods out of self‐interest, fiscal mechanisms for promoting sustainable forest management may be needed.
Transplantation of the SubshrubLotus scoparius: Testing the Home‐Site Advantage Hypothesis
Authors: Montalvo Arlee M. , Ellstrand Norman C.
Published: March 2003

Abstract:The long‐term success of restored populations may be jeopardized by the collection locality of transplants if they are ill matched to their new environment. The home‐site advantage hypothesis predicts that the relative success of introduced populations will decrease as their genetic and environmental distance to the local native population increases. We evaluated this hypothesis for a geographically variable shrub,Lotus scoparius, in southern Californian coastal sage scrub by planting two common‐garden experiments with seedlings from 12 source populations. The common‐garden sites differed in environment and were each home to different source populations of the two taxonomic varieties,L. s.var.scopariusorL. s. var.brevialatus. We used allozyme data from each source population to calculate genetic distances between populations, and a combination of climatic data and soil traits to calculate environmental distances. At the more mesic, coastal common garden, cumulative fitness of transplants (survival × flower production) was inversely related to genetic distance between source and resident populations. At the more xeric, inland common garden, cumulative fitness (survival × size) decreased significantly with both genetic and environmental distance after one taxonomic variety was excluded from analyses. Geographic distance was only weakly correlated with genetic distance and had little value in predicting cumulative fitness of transplants. Our data support the home‐site advantage hypothesis and the idea that mis‐matching source populations of these genetically differentiated seed sources may result in lowered success of restored or constructed populations. The genetic and environmental similarities of source populations should be considered when source materials are chosen for transplantation.
Estimate of the Area Affected Ecologically by the Road System in the United States
Authors: Forman Richard T. T.
Published: March 2003

Abstract: In view of an extensive road system, abundant and rapidly growing vehicular traffic, and a scattered literature indicating that some ecological effects of roads extend outward for >100 m, it seems likely that the cumulative ecological effect of the road system in the United States is considerable. Two recent studies in The Netherlands and Massachusetts ( U.S.A.) evaluated several ecological effects of roads, including traffic noise effects, and provide quantitative evidence for a definable “road‐effect zone.” Based on the approximate width of this asymmetric convoluted zone, I estimate that about one‐fifth of the U.S. land area is directly affected ecologically by the system of public roads. I identify a series of assumptions and variables suggesting that over time this preliminary estimate is more likely to rise than drop. Several transportation planning and policy recommendations, ranging from perforating the road barrier for wildlife crossings to closing certain roads, offer promise for reducing this enormous ecological effect.
Historic Fire Regime in Southern California Shrublands
Authors: Keeley Jon E. , Fotheringham C. J.
Published: March 2003

Abstract:Historical variability in fire regime is a conservative indicator of ecosystem sustainability, and thus understanding the natural role of fire in chaparral ecosystems is necessary for proper fire management. It has been suggested that the “natural” fire regime was one of frequent small fires that fragmented the landscape into a fine‐grained mixture of age classes that precluded large, catastrophic fires. Some researchers claim that this regime was lost because of highly effective fire suppression and conclude that if fire managers could “restore” a regime of frequent fires with widespread prescription burning, they could eliminate the hazard of catastrophic fires. The primary evidence in support of this model is a study that compared contemporary burning patterns in southern California, U.S.A., a region subject to fire suppression, with patterns in northern Baja California, Mexico, where there is less effective fire suppression. We found that differences in fire regime between these two regions are inconclusive and could not be ascribed conclusively to differences in fire suppression. Historical records suggest that the natural fire regime in southern California shrublands was rather coarse‐grained and not substantively different from the contemporary regime. There is no evidence that fire‐management policies have created the contemporary fire regime dominated by massive Santa Ana wind‐driven fires. Increased expenditures on fire suppression and increased loss of property and lives are the result of human demographic patterns that place increasing demand on fire‐suppression forces.
Positive Feedbacks among Forest Fragmentation, Drought, and Climate Change in the Amazon
Authors: Laurance William F. , Williamson G. Bruce
Published: March 2003

Abstract: The Amazon basin is experiencing rapid forest loss and fragmentation. Fragmented forests are more prone than intact forests to periodic damage from El Niño–Southern Oscillation ( ENSO) droughts, which cause elevated tree mortality, increased litterfall, shifts in plant phenology, and other ecological changes, especially near forest edges. Moreover, positive feedbacks among forest loss, fragmentation, fire, and regional climate change appear increasingly likely. Deforestation reduces plant evapotranspiration, which in turn constrains regional rainfall, increasing the vulnerability of forests to fire. Forest fragments are especially vulnerable because they have dry, fire‐prone edges, are logged frequently, and often are adjoined by cattle pastures, which are burned regularly. The net result is that there may be a critical “deforestation threshold” above which Amazonian rainforests can no longer be sustained, particularly in relatively seasonal areas of the basin. Global warming could exacerbate this problem if it promotes drier climates or stronger ENSO droughts. Synergisms among many simultaneous environmental changes are posing unprecedented threats to Amazonian forests.
Reduced Feather Growth Rates of Two Common Birds Inhabiting Central Amazonian Forest Fragments
Authors: Stratford Jeffrey A. , Stouffer Philip C.
Published: March 2003

Abstract:Forest fragmentation may negatively affect populations typically found within continuous forest tracts. Some effects, such as absence from small fragments, are obvious, but other effects may be subtle and easily overlooked. We evaluated the hypothesis that forest birds dwelling in fragments, where microclimatic conditions have been shown to be hotter and drier than in continuous forest, may be in poorer physiological condition than those in the forest interior. We studied two bird species, the Wedge‐billed Woodcreeper ( Glyphorynchus spirurus) and the White‐crowned Manakin (   Pipra pipra), common to the fragmented landscape north of Manaus, Brazil. We analyzed feather growth rates in Pipra and Glyphorynchus captured in 1‐, 10‐, and 100‐ha forest fragments and continuous forest. Mean daily feather growth rates of the outer right rectrix of birds captured in fragments were significantly slower than feather growth rates of birds captured in continuous forest. Based on recapture data, Wedge‐billed Woodcreepers probably grew their feathers in sites where they were first captured. White‐crowned Manakins, however, were highly mobile and were recaptured rarely. Although we cannot conclusively show that fragmentation caused birds to be in poorer physiological condition, the data indicate that birds in poorer physiological condition were more likely to be captured in fragments than in continuous forest. Thus, our data suggest that forest fragmentation may have subtle but important effects on species that are relatively common after landscape alteration.
Effect of Road Traffic on Two Amphibian Species of Differing Vagility
Authors: Carr Laurie W. , Fahrig Lenore
Published: March 2003

Abstract:Vehicular traffic can be a major source of mortality for some species. Highly vagile organisms may be at a disadvantage in landscapes with roads because they are more likely to encounter roads and incur traffic mortality. To test this prediction, we assessed the population abundance of two anuran species of differing vagility, the leopard frog (   Rana pipiens, more vagile) and the green frog (   Rana clamitans, less vagile), at 30 breeding ponds. Traffic density, an index of the amount of potential traffic mortality, was measured in concentric circles radiating from the ponds out to 5 km. We conducted multiple linear regressions relating population abundance to traffic density, pond variables, and landscape habitat variables and found that leopard frog population density was negatively affected by traffic density within a radius of 1.5 km. There was no evidence that the presence of vehicular traffic affected green frog populations. These results suggest that traffic mortality can cause population declines and that more vagile species may be more vulnerable to road mortality than less vagile species.
Noninvasive Stress and Reproductive Measures of Social and Ecological Pressures in Free‐Ranging African Elephants
Authors: Foley C. A. H. , Papageorge S. , Wasser S. K.
Published: March 2003

Abstract:The African elephant (  Loxodonta africana) experienced a poaching‐related 60% population decline between 1979 and 1988 that was inordinately concentrated on adults. This, coupled with political pressures to delist the elephant, has created a need for noninvasive physiological measures that can quantify the long‐term effects of past mortality patterns of this long‐lived species. We collected fresh fecal samples from 16 female elephants in three different groups over 23 months at Tarangire National Park, Tanzania, and analyzed them for fecal progesterone and cortisol metabolites. Social and ecological measures were collected concurrently. Fecal progesterone metabolite measures corresponded significantly with stage of gestation, and appear to be able to confirm pregnancy in female elephants from as early as 3 months of gestation. We found that progesterone metabolite concentrations were significantly lower during the dry season than during the wet season after controlling for stage of gestation. Fecal cortisol metabolite concentrations showed the opposite seasonal pattern, being significantly higher in the dry season and inversely correlated with rainfall across seasons. Fecal cortisol metabolite concentrations also increased with group size and were correlated positively with dominance rank in the largest group. Our results suggest that measures of progesterone and cortisol metabolites in feces provide indices of reproductive function and physiological stress that can quantify both natural and human disturbances in African elephants. These measures are ideally suited for monitoring the long‐term effects of social disruption from poaching and a variety of other management concerns.
Beyond Biology: toward a More Public Ecology for Conservation
Authors: Robertson David P. , Hull R. Bruce
Published: March 2003

Abstract:The ultimate purpose of conservation science is to inform and affect conservation policy. Therefore, conservation biologists and all the people who produce, review, and apply conservation research should evaluate the success of their knowledge according to its ability to influence conservation decisions. In addition to possessing conventional “scientific” attributes such as validity, generalizability, and precision, conservation knowledge must also possess qualities that make it effective in the political arena of decision making. “Public ecology” is a philosophy and practice of conservation science that goes beyond biology and beyond the norms of modern science to construct knowledge that is useful for environmental decision making. As post‐normal conservation science, public ecology is defined by the following six attributes: evaluative, contextual, multiscalar, integrative, adaptive, and accessible. We discuss the need for a more public ecology and describe the qualites that make it a more powerful ecology.
Effects of Population Size and Food Stress on Fitness‐Related Characters in the Scarce Heath, a Rare Butterfly in Western Europe
Authors: Cassel Anna , Windig Jack , Nylin Sören , Wiklund Christer
Published: March 2003

Abstract: Knowledge about the effects of inbreeding in natural populations is scarce, especially in invertebrates. We analyzed to what extent fitness‐related traits in the scarce heath ( Coenonympha hero), a butterfly, are affected by population size and isolation and whether differences in food quality influence these effects. We categorized nine populations as either large or small and isolated. Full‐sib groups of offspring from 27 females were followed under seminatural conditions. Because of increased zygote mortality, egg hatchability was significantly lower in the small and isolated populations than in the large ones. Population category had no effect on larval weight under optimal conditions, but weight was significantly lower in the small‐isolated category with low food quality. The effects of inbreeding can thus be hidden when conditions are benign but can appear under stress. Survival also differed significantly between population categories, and larval developmental time tended to be longer in the small‐isolated category, irrespective of food conditions. We suggest that the differences in fitness between offspring from large and small isolated populations are at least partly due to inbreeding. This adds a further threat to a species that is already suffering from decreasing population sizes and increasing isolation among populations.
Buffer‐Zone Distances to Protect Foraging and Loafing Waterbirds from Disturbance by Personal Watercraft and Outboard‐Powered Boats
Authors: Rodgers James A. , Schwikert Stephen T.
Published: March 2003

Abstract: Outdoor recreation and ecotourism can have negative effects on wildlife species, so it is important to determine buffer zones within which activities near critical wildlife areas are limited. We exposed 23 species of waterbirds ( Pelecaniformes, Ciconiiformes, Falconiformes, Charadriiformes) to the direct approach of a personal watercraft ( PWC) and an outboard‐powered boat to determine their flush distances. We used 11 sites with a mixture of low, moderate, and high amounts of human activity along the east and west coasts of Florida during September–November 1998 and April–June 1999. We detected considerable variation in flush distances among individuals within the same species and among species in response to both types of vessels. Average flush distances for the PWC ranged from 19.5 m (  Least Tern [ Sterna antillarum]) to 49.5 m (Osprey [  Pandion haliaetus]), whereas average flush distances for the outboard‐powered boat ranged from 23.4 m ( Forster's Tern [ S. forsteri]) to 57.9 m (Osprey). Larger species generally exhibited greater average flush distances for both types of watercraft. A comparison of the flush distances elicited by each watercraft indicated that only the Great Blue Heron (Ardea herodias) exhibited significantly larger flush distances ( t test, p < 0.01) in response to the approach of the PWC than in response to the outboard, whereas four species (Anhinga [Anhinga anhinga], Little Blue Heron [Egretta caerulea], Willet [Catoptrophorus semipalmatus], and Osprey) exhibited significantly larger flush distances ( t test, p < 0.05) in response to the approach of the outboard‐powered boat than in response to the PWC. Eleven species (68.8%) showed no significant difference ( t test, p> 0.05) in their flush distances in response to the fast‐moving PWC and the outboard‐powered boat. Our data suggest that a single buffer‐zone distance can be developed for both PWC and outboard‐powered vessels. Buffer zones of 180 m for wading birds, 140 m for terns and gulls, 100 m for plovers and sandpipers, and 150 m for ospreys would minimize their disturbance at foraging and loafing sites in Florida.
Arthropod Morphospecies versus Taxonomic Species: a Case Study with Araneae, Coleoptera, and Lepidoptera
Authors: Derraik José G. B. , Closs Gerard P. , Dickinson Katharine J. M. , Sirvid Philip , Barratt Barbara I. P. , Patrick Brian H.
Published: March 2003

Abstract:In times of biodiversity crisis there is an increasing need for faster and cheaper methods by which to achieve conservation goals. This situation is especially troublesome for invertebrates, and the use of morphospecies instead of taxonomic species has been proposed as a way around the taxonomic constraints in particular situations. We conducted a study in a modified native shrubland on New Zealand's South Island in which we sampled Lepidoptera, Coleoptera, and Araneae in autumn by beating and pitfall traps. All specimens were separated into morphospecies by a nonspecialist and identified by specialized taxonomists, and the results were compared. Results were analyzed with respect to correct separations (one taxonomic species to one morphospecies), lumping (more than one species classified as a single morphospecies), and splitting (one species separated into more than one morphospecies). Among the individual orders, Lepidoptera yielded the most accurate results (91% correct separation), whereas Coleoptera and Araneae yielded poor results (63% and 50%, respectively). The overall difference between the morphospecies and taxonomic species estimates for the site was only 3.3%, but this was an artifact caused by the splitting and lumping results balancing each other out. The accuracy of morphospecies separation varies greatly among different invertebrate groups, so the relationship between morphospecies and taxonomic species for a particular target group must be established beforehand. We recommend that some prior orientation should be given by expert taxonomists. When adopted with care, morphospecies present a useful tool for conservation, particularly for environmental impact assessment and when inventorying diversity does not require information on particular species.
Habitat Loss and Extinction in the Hotspots of Biodiversity
Authors: Brooks Thomas M. , Mittermeier Russell A. , Mittermeier Cristina G. , Da Fonseca Gustavo A. B. , Rylands Anthony B. , Konstant William R. , Flick Penny , Pilgrim John , Oldfield Sara , Magin Georgina , Hilton‐Taylor Craig
Published: March 2003

Abstract: Nearly half the world's vascular plant species and one‐third of terrestrial vertebrates are endemic to 25 “hotspots” of biodiversity, each of which has at least 1500 endemic plant species. None of these hotspots have more than one‐third of their pristine habitat remaining. Historically, they covered 12% of the land's surface, but today their intact habitat covers only 1.4% of the land. As a result of this habitat loss, we expect many of the hotspot endemics to have either become extinct or—because much of the habitat loss is recent—to be threatened with extinction. We used World Conservation Union [ IUCN ] Red Lists to test this expectation. Overall, between one‐half and two‐thirds of all threatened plants and 57% of all threatened terrestrial vertebrates are hotspot endemics. For birds and mammals, in general, predictions of extinction in the hotspots based on habitat loss match numbers of species independently judged extinct or threatened. In two classes of hotspots the match is not as close. On oceanic islands, habitat loss underestimates extinction because introduced species have driven extinctions beyond those caused by habitat loss on these islands. In large hotspots, conversely, habitat loss overestimates extinction, suggesting scale dependence (this effect is also apparent for plants). For reptiles, amphibians, and plants, many fewer hotspot endemics are considered threatened or extinct than we would expect based on habitat loss. This mismatch is small in temperate hotspots, however, suggesting that many threatened endemic species in the poorly known tropical hotspots have yet to be included on the IUCN Red Lists. We then asked in which hotspots the consequences of further habitat loss (either absolute or given current rates of deforestation) would be most serious. Our results suggest that the Eastern Arc and Coastal Forests of Tanzania‐Kenya, Philippines, and Polynesia‐Micronesia can least afford to lose more habitat and that, if current deforestation rates continue, the Caribbean, Tropical Andes, Philippines, Mesoamerica, Sundaland, Indo‐Burma, Madagascar, and Chocó–Darién–Western Ecuador will lose the most species in the near future. Without urgent conservation intervention, we face mass extinctions in the hotspots.
Illicit Crops and Bird Conservation Priorities in Colombia
Authors: Álvarez Maria D.
Published: March 2003

Abstract: Over the last 5 years the amount of land in Colombia planted in illicit crops, such as coca and poppy, has grown an average of 21% per year and may account for half the total area deforested in 1998. I conducted a geographic analysis of the distribution of illicit crops relative to standing forests and areas of conservation priority for birds. Municipalities where illicit crops have been detected were overlaid on a forest‐cover map of Colombia and two types of conservation priorities for birds were plotted: distributions of threatened species and minimum‐area sets for conservation of all species. The sites of the highest conservation priority affected by illicit crops were in the southern Andes, the northern West Andes and adjacent Darién lowlands, the Sierra Nevada de Santa Marta, Serranía del Perijá, and the Serranía de San Lucas. The largest forested areas threatened by illicit crops were in Amazonia and the Amazonian foothills of the East Andes, sites of low conservation priority. Given current trends in the expansion of illicit crops and the narrow endemicity of some bird species, the conversion of forests for illicit‐crop cultivation may result in the extirpation of several bird species from affected regions. To impede this, those involved in illicit‐crop eradication and alternative development should give high priority to the protection of existing forest reserves and parks from the planting of illicit crops. Such efforts should also extend to areas proposed for conservation based on the diversity of threatened and endemic birds that are currently unprotected. The conservation of threatened and endemic birds in Colombian forests may hinge on successfully curbing incentives for deforestation, including the international trade in illicit drugs.
Assessing the Roles of Patch Quality, Area, and Isolation in Predicting Metapopulation Dynamics
Authors: Fleishman Erica , Ray Chris , Sjögren‐Gulve Per , Boggs Carol L. , Murphy Dennis D.
Published: March 2003

Abstract:Two aspects of patch geometry—area and isolation—currently dominate the field of metapopulation dynamics. Under this area‐and‐isolation paradigm, models commonly assume that the probability of local extinction decreases as patch area increases and that the probability of colonization increases as patch connectivity increases. Environmental variables other than patch area and isolation are assumed to have relatively little effect on metapopulation dynamics. Our work on a metapopulation of the butterflySpeyeria nokomis apacheanahighlights the need for a broader view of metapopulation dynamics. In this system, neither occupancy nor turnover patterns were best modeled as functions of patch area or isolation. Instead, other measures of habitat quality explained the most variance in occupancy and turnover. Our study also revealed temporal variation in the factors associated with occupancy and turnover. This variation can cause the results of analyses to vary with the temporal scale of analysis. For example, factors associated with turnover in this system differed among single‐year and multiple‐year analyses. We emphasize that factors other than patch geometry may drive extinction and colonization processes in metapopulations, especially in systems that experience substantial natural and anthropogenic environmental variability.
Modeled Effects of Sagebrush‐Steppe Restoration on Greater Sage‐Grouse in the Interior Columbia Basin, U.S.A.
Authors: Wisdom Michael J. , Rowland Mary M. , Wales Barbara C. , Hemstrom Miles A. , Hann Wendel J. , Raphael Martin G. , Holthausen Richard S. , Gravenmier Rebecca A. , Rich Terrell D.
Published: March 2003

Abstract: Habitats of Greater Sage‐Grouse (Centrocercus urophasianus) have declined across western North America, and most remaining habitats occur on lands administered by the U.S. Forest Service ( FS) and U.S. Bureau of Land Management ( BLM). Consequently, managers of FS–BLM lands need effective strategies to recover sagebrush (Artemisia spp.) habitats on which this species depends. In response to this need, we evaluated the potential benefits of two restoration scenarios on Greater Sage‐Grouse in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States. Scenario 1 assumed a 50% reduction in detrimental grazing effects (through changes in stocking rates and grazing systems) and a six‐fold increase in areas treated with active restoration (e.g., prescribed burning, native seedings, wildfire suppression) compared with future management proposed by the FS–BLM. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same increase in active restoration as scenario 1. To evaluate benefits, we estimated the risk of population extirpation for sage grouse 100 years in the future under the two scenarios and compared this risk with that estimated for proposed (100‐year) FS–BLM management. We used estimates of extirpation risk for historical (circa 1850–1890) and current time periods as a context for our comparison. Under historical conditions, risk of extirpation was very low on FS–BLM lands, but increased to a moderate probability under current conditions. Under proposed FS–BLM management, risk of extirpation on FS–BLM lands increased to a high probability 100 years in the future. Benefits of the two restoration scenarios, however, constrained the future risk of extirpation to a moderate probability. Our results suggest that expansive and sustained habitat restoration can maintain desired conditions and reduce future extirpation risk for sage grouse on FS–BLM lands in western North America. The continued spread of exotic plants, however, presents a formidable challenge to successful restoration and warrants substantial research and management attention.