Novel genes continue to enhance population growth in adders (Vipera berus)

In 1999, we published a report on how an introduction of 20 males into a severely inbred and isolated population of adders (Vipera berus) halted its decline towards extinction, induced a profound change in population genetic variability, resulted in a dramatic increase in offspring viability and thus in a rapid increase in numbers. Since the publication of our paper we have received numerous inquiries as to whether we have continued to monitor this population, as this is the case we herein present population demographic data gathered between 1981 and 2003. The population has continued to increase in numbers and in 2003, we collected 39 adult male adders, more than at any time over the 23-year study. Our continued work, hence, lends strong support to the importance of novel genes in enhancing the viability of inbred populations and supports the importance of preserving genetic variability in order to maintain viable wild populations.     

ITS1-rDNA-based methodology to identify world-wide hake species of the Genus Merluccius

Species-specific DNA-based tags are valuable tools for the management of both fisheries and commercial fish products. In this study, we have developed a two-step molecular tool to detect the presence of hake DNA (Merluccius spp.) and to identify the exact hake species present in an blind sample. The first test involves PCR amplification of an ITS1-rDNA fragment of 193 bp using nested primers that are interspecifically conserved in Merluccius spp. and Atlantic cod, Gadus morhua. The second test consists of the PCR amplification of a 602-659 bp DNA fragment spanning part of the ribosomal cluster 18S-ITS1-5.8S and digesting it with four restriction enzymes whose targets map at interspecifically nonconserved sites of the ITS1. Alternatively, the identification of hake species can be achieved by FINS or BLAST, using the nucleotide sequence of either the whole ITS1 sequence or its nested fragment of 193 bp. Because of their high reproducibility and ease of execution, these procedures allow for routine analysis and constitute high reliable tools for the rapid identification of 12 species of hake.     

Long-term conservation efforts contribute to positive green turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica

Worldwide, green turtle Chelonia mydas populations have declined and the species is classified as globally endangered. Tortuguero, Costa Rica, hosts the largest remaining green turtle rookery in the Atlantic basin. Tortuguero green turtles have been hunted since pre-Columbian times. Monitoring and conservation of the green turtle population began in 1955. The long-term efforts provide an excellent opportunity to evaluate the success of sea turtle conservation action and policies. Nest counts conducted 1971-2003 were analyzed to: (1) determine the nesting trend, (2) estimate rookery size and (3) identify events and policy decisions influencing the trend. A nonparametric regression model indicates a 417% increase in nesting over the study period. Rookery size was defined as the mean number of nests 1999-2003 and estimated at 104,411 nests year⁻¹, corresponding to 17,402-37,290 nesting females year⁻¹. A comparison with 34 index populations verifies Tortuguero as one of the two largest green turtle rookeries worldwide. Events and policy decisions in Costa Rica, Nicaragua, and Panama that comprise the main nesting, feeding and mating grounds for the Tortuguero population are likely to have had the greatest influence on green turtle survivorship. Conservation efforts and policies catalyzing increased hatchling production and decreased adult and juvenile mortality since 1963 have contributed to the positive nesting trend. The trend demonstrates that long-term conservation efforts can reverse nesting declines and offers hope that adequate management can result in recuperation of endangered sea turtle species.     

Effects of oxidized dietary oil and vitamin E supplementation on lipid profile and oxidation of muscle and liver of juvenile atlantic cod (Gadus morhua)

The effects of oxidized dietary lipid and the role of vitamin E on lipid profile, retained tocopherol levels, and lipid oxidation of juvenile Atlantic cod (Gadus morhua) were evaluated following a 9-week feeding trial. Four isonitrogenous experimental diets containing fresh or oxidized (peroxide value of 94 mequiv/kg) fish oil with or without added vitamin E (alpha-tocopherol or mixed tocopherols) were fed to juvenile cod in duplicate tanks. There was no significant (P > 0.05) influence on major lipid classes of cod liver and muscle by diet with the exception of sterols. Sterols content was increased in liver but decreased in muscle by oxidized dietary oil in the absence of vitamin E. Dietary vitamin E supplementation decreased the sterols level in cod liver but with no significant (P > 0.05) effect on their level in the muscle. Fatty acid composition varied between lipid fractions in muscle tissue and was affected by the diet. Oxidized oil significantly (P < 0.05) decreased the deposition of alpha-tocopherol in liver but not in muscle. gamma- and delta-Tocopherols from dietary tocopherol mixtures were retained at very low levels in liver, but higher retention was observed in muscle tissue. The oxidative state of both liver and muscle, as measured by the 2-thiobarbituric acid reactive substances (TBARS) and headspace propanal, negatively correlated with tissue vitamin E levels. It is suggested that oxidized oil affected juvenile Atlantic cod by causing vitamin E deficiency in certain tissues and that these effects could be alleviated by supplementation of a sufficient amount of dietary vitamin E. The results also indicate that mixed tocopherols were good antioxidants for Atlantic cod, although less effective than alpha-tocopherol alone in many tissues with the exception of muscle, where gamma- and delta-tocopherols were deposited at relatively high levels.     

Bycatches of common guillemot (Uria aalge) in the Baltic Sea gillnet fishery

Bycatch of common guillemots (Uria aalge) appears to be the single most serious threat to the population, and the proportion of recoveries of ringed birds in fishing gear, compared with other finding circumstances, has significantly increased during a 28 year period (P<0.01). Out of 1952 ringed common guillemots reported found between 1972 and 1999 in the Baltic Sea, 980 (50.2%) were caught in fishing gear. The bycatch in set gillnets for cod (Gadus morhua) constituted 22.3%, drift gillnets for salmon (Salmo salar) 65.5%, and other fishing gear 12.2%. The proportion of recoveries in cod gillnets has significantly increased during the study period (P<0.05), while no clear trend was observed in the recoveries in salmon gillnets. The Swedish fishing effort follows a similar pattern for cod but has decreased for salmon. The observed increased use of cod gillnets in the Baltic Sea may have contributed to the observed decrease in adult survival rate, and we provide two different estimates suggesting that significant proportions of the guillemot population are caught annually in the Baltic Sea gillnet fishery. We suggest several available techniques to reduce bycatch in the Baltic Sea fishery.     

Removing erosion control projects increases bank swallow (Riparia riparia) population viability modeled along the Sacramento River, California, USA

Spatially-explicit population viability analysis (PVA) is a powerful method for modeling the extinction risk of populations that show variation over space and time. It is especially effective for comparing relative effect of different management scenarios on population dynamics. Here, I present a habitat patch-based PVA for a population of the California state-listed threatened bank swallow (Riparia riparia) nesting along the Sacramento River. This model incorporates the effects of habitat availability and location, density dependence, site fidelity, and stochasticity in survival and fecundity. River bank habitat patches suitable for this species were delineated using a geographic information systems (GIS) model of river bank height and were used in a PVA scenario analysis to assess the effects of habitat restoration—that could occur by removing bank erosion control projects (bank revetment)—on population viability. Sensitivity analysis showed that the model estimated probability of quasi-extinction (dropping below 2000 breeding pairs) ranged from 0 to 0.8 depending on the input parameters, with juvenile survival causing the greatest variability. However, comparing changes to the probability of quasi-extinction between the restored habitat scenario and current conditions showed a consistent 40-60% decrease in probability of quasi-extinction across all parameter combinations. The results of this research reaffirm the need for continued protection of the bank swallow as a listed species indicate that the removal of bank erosion control projects would increase viability of this population.     

Relative effects of management and environmental conditions on performance and survival of populations of a terrestrial orchid, Dactylorhiza majalis

For population viability analysis of endangered orchid populations, it is crucial to disentangle the effects of weather and management from intrinsic orchid dynamics. When doing this, typically several months’ average temperatures and/or sums of precipitations are compared with some characteristics of plant performance. Here we tested, whether short averaging intervals (1-2 weeks) are more closely correlated with orchid performance. We used 5 years of data from five Dactylorhiza majalis populations, and have shown that the improvement of prediction by shortening the interval over which the temperatures are averaged or precipitation summed, even if detectable, is only weak and not significant. This, however, may be due to low weather variability during the study. Regarding the second aspect, the effect of management (presence or absence of mowing), we have found that leaf area of D. majalis at the regularly mown site was larger than that at the sites which were mown only once in 2 years, but we did not detect a significant effect of the absence of mowing on the incidence of flowering. Mowing can affect orchid performance in two ways: by reduced shading of orchids and by reducing competition with other species. Therefore, we have determined the co-occurring species associated with presence or absence of mowing and found that shading significantly affected the length of the flower stalk, the ratio of leaf width to leaf length at the end of the season, but did not affect seed weight and probability of flowering the next year. We conclude that the most appropriate management for D. majalis is mowing at least once a year, ideally at the end of June/beginning of July, after its fruiting.     

Phenotypic differentiation in fitness related traits between populations of an extremely rare sunflower: Conservation management of isolated populations

Knowledge of the genetic and demographic consequences of rarity is crucial when evaluating the effects of habitat loss and fragmentation on population viability, and for creating management plans in rare plant species. Reduction in population size and in the number of populations can lead to decreased genetic diversity and increased inbreeding. Genetic diversity is often correlated with fitness and is frequently used to identify populations of greatest conservation concern, or those that may be good candidates for ex situ conservation programs. However, an association between these factors is not always clear, and crossing studies evaluating whether there is phenotypic differentiation among populations in fitness related traits can inform managers of suffering populations or good sources for ex situ materials. Crossing studies can also evaluate the potential for genetic rescue to boost fitness in suffering populations. To address these questions, we conducted two generations of controlled crosses between populations of the extremely rare and fragmented sunflower, Helianthus verticillatus. We measured achene viability, germination, survival, and pollen viability (F₁ only) in 176 F₁ and 159 F₂ families. The populations were differentiated with respect to phenotypic fitness measures with one population having significantly lower achene viability and germination. Also, the potential for genetic rescue was observed as gene flow into the less fit population resulted in higher fitness measures in both the F₁ and F₂. Results are discussed with respect to the importance of combining genetic marker data with crosses and the implications for conservation in disjunct populations of rare species.     

Metapopulation dynamics and conservation of the marsh fritillary butterfly: Population viability analysis and management options for a critically endangered species in Western Europe

This study investigates the dynamics and viability of a marsh fritillary butterfly Euphydryas aurinia metapopulation in a Belgian successional landscape. Based on capture-mark-recapture and winter nest census data, we first estimated demography (survival and recruitment rates, population size, density dependence) and dispersal parameters (emigration rate, effect of patch connectivity on dispersal, mortality during dispersal). Then using RAMAS/GIS platform, we parameterised a population viability analysis (PVA) model with these parameters to simulate the future of this metapopulation under different scenarios.The metapopulation does not seem viable even if natural reforestation is controlled by adequate management. In its present state, the patch system is not able to sustain enough individuals: due to the large temporal fluctuations in demographic parameters, a carrying capacity far higher than currently would be necessary to limit extinction risk to 1%, suggesting the existence of an extinction debt for the species in Belgium. The situation of E. aurinia appears much worse compared to two other fritillary species threatened in Belgium, for which similar PVA are available. It is therefore urgent to increase the carrying capacity of the patch system. How and where it is achieved are of secondary importance for the gain in viability: improvement of habitat quality through restoration, or increase of habitat quantity via enlargement of existing patches and/or creation of new habitat in the matrix. A regime of management based on regular re-opening and maintenance of habitat patches may be the only guarantee of long-term persistence for this critically endangered species in Belgium.     

Distribution and status of manatees Trichechus spp. Near the mouth of the amazon river,Brazil

Interviews with hunters and collection of skulls indicate that Trichechus inunguis occurs throughout the region of the Amazon River estuaries from Amapá to the mainland of Pará, including Ilha de Marajó and islands on its Atlantic coast. T. manatus has a disjunct distribution in Brazil, apparently occurring both on the coast of Amapá north of Cabo Norte and in the Rio Mearim (Maranhão) as well as further to the southwest; it seems to have been exterminated from the Atlantic coast of Pará and is absent from the Marajó region. Continued subsistence hunting can best be controlled by destruction of illegal camboas (fence-like traps) which catch manatees at high tide. Areas deserving study are the coast and inland lakes of eastern Amapá, the only place in the world where two sirenian species might still be found in sympatry or immediate proximity, and the lower Rio Mearim in Maranhão, which may still contain a sizable population of T. manatus. Ecological studies in these areas should have particular relevance to hypotheses of sirenian evolutionary interactions, and manatee reserves should be established in both areas.     

Breeding system and inbreeding depression in the clonal plant species Knautia arvensis (Dipsacaceae): implications for survival in abandoned grassland

Larger clonal sizes observed in abandoned than in managed grassland could result in increased geitonogamy in Knautia arvensis. The species was investigated for self-compatibility, seed set without pollinators, and inbreeding depression in a greenhouse experiment. Seed set was equivalent in hand-selfed and hand-outcrossed plants (c. 53%), indicating full self-compatibility. Seed set was low (2.8%) in caged, unmanipulated flower heads. There was no significant difference in seed weight, germination, and survival between selfed and outcrossed progeny. Juvenile biomass was significantly lower in selfed than in outcrossed progeny (on average 45% lower). Cumulative fitness calculations for germination, survival, and juvenile biomass showed that the mean inbreeding depression was 58% in offspring produced by selfing. The results suggest that in K. arvensis, which is protected against self-pollination within flower heads through protandry, the likely mechanism for selfing is via geitonogamy among flower heads. Geitonogamy among ramets within the larger clones observed in abandoned grassland could reduce offspring viability in K. arvensis since the fitness of selfed offspring was low. Inbreeding depression could therefore add to the recruitment problems experienced by plants in abandoned grassland, both in K. arvensis and probably in other clonal grassland species, depending on their growth structure and breeding system.     

Population viability of Cape mountain zebra in Gamka Mountain Nature Reserve, South Africa: the influence of habitat and fire

The small Cape mountain zebra population in Gamka Mountain Nature Reserve represents a third of the entire gene pool of this endangered species and is thus vital for it’s conservation. Presently, management of this population is largely hands off, with the belief that it will grow to levels which will allow it to form a source for the mixing of mountain zebra stocks in the future. The growth of this population however, has been slow and we investigated the influence of habitat and fire on this growth. Firstly, we used a diffusion model to perform a population viability analysis. This analysis indicated that the population had a low probability of attaining quasi-extinction in the next 50 years (G = 0.0032). However, our findings indicated that less than 30% of the reserve was suitable for mountain zebra and that the preferred habitat would have to be burnt at unnaturally short intervals to sustain the present growth. We therefore argue that the risk of quasi-extinction to this population is greater than predicted and suggest that management options need to be implemented to reduce this risk. These options include; translocation to another protected area; acquisition of adjacent land; burning preferred habitat at unnaturally short intervals; forming a conservancy with adjacent landowners; leasing cultivated land for pasture. We suggest that only the latter two options are likely to stimulate mountain zebra population growth in the short term and that these should receive immediate attention.     

Wild-captive metapopulation viability analysis

We developed an interactive management model for wild and captive populations of the ploughshare tortoise or angonoka, Geochelone yniphora. Interactive management is based on the translocation of individuals between wild and captive populations to simulate a metapopulation. Demographic parameters of one captive and two wild populations of this rare tortoise were used to conduct a metapopulation viability analysis (MVA). The effectiveness of the conservation strategy proposed for this species was then evaluated by modifying the probability of extinction and growth of the metapopulation over a fixed period of time. Several alternative scenarios of interactive management were then tested and ranked in terms of their effect on the viability of the metapopulation. The model predicted that catastrophic events such as bush fires would likely have a negative effect on the future of remaining wild populations. However, the model also predicted that the use of captive-born offspring to establish additional wild populations would decrease the risk of extinction of the metapopulation as a whole. We believe that, when supported by sound knowledge of the demographic parameters of a species, the use of MVA as part of an interactive management program can be an effective conservation tool that allows assessment of the probable response of both captive and wild populations to different management alternatives. One of the most interesting aspects of this interactive management approach is the link between in situ and ex situ conservation.     

Regional population viability of grassland songbirds: Effects of agricultural management

Although population declines of grassland songbirds in North America and Europe are well-documented, the effect of local processes on regional population persistence is unclear. To assess population viability of grassland songbirds at a regional scale (∼150,000 ha), we quantified Savannah Sparrow Passerculus sandwichensis and Bobolink Dolichonyx oryzivorus annual productivity, adult apparent survival, habitat selection, and density in the four most (regionally) common grassland treatments. We applied these data to a female-based, stochastic, pre-breeding population model to examine whether current grassland management practices can sustain viable populations of breeding songbirds. Additionally, we evaluated six conservation strategies to determine which would most effectively increase population trends. Given baseline conditions, over 10 years, simulations showed a slightly declining or stable Savannah Sparrow population (mean bootstrap λ = 0.99; 95% CI = 1.00-0.989) and severely declining Bobolink population (mean bootstrap λ = 0.75; 95% CI = 0.753-0.747). Savannah Sparrow populations were sensitive to increases in all demographic parameters, particularly adult survival. However for Bobolinks, increasing adult apparent survival, juvenile apparent survival, or preference by changing habitat selection cues for late-hayed fields (highest quality) only slightly decreased the rate of decline. For both species, increasing the amount of high-quality habitat (late- and middle-hayed) marginally slowed population declines; increasing the amount of low-quality habitat (early-hayed and grazed) marginally increased population declines. Both species were most sensitive to low productivity and survival on early-hayed fields, despite the fact that this habitat comprised only 18% of the landscape. Management plans for all agricultural regions should increase quality on both low- and high-quality fields by balancing habitat needs, nesting phenology, and species’ response to management.     

Cost-efficient conservation for the white-banded tanager (Neothraupis fasciata) in the Cerrado, central Brazil

Population viability analyses are widely used to support decisions for the management of single species, but there are few studies that explicitly take into account realistic economic costs. In this study we determine the most cost-efficient conservation management options for the white-banded tanager (Neothraupis fasciata) in the protected areas of the Cerrado in central Brazil. We use the PVA model VORTEX to simulate the ability of different management options to improve population persistence and then assess the effectiveness of each option given a fixed budget. We discover that the best strategy for improving the viability of white-banded tanager populations is to use fire management and nest protection to increase fecundity. In small reserves and a low budget then fire management alone is the best strategy, but if the budget is larger fire management with nest protection as a mixed strategy is better. In large reserves the best strategy is to do nest protection and with large budgets there is a negligible difference between spending all the money on nest protection versus a mixed strategy. If we had not included financial considerations in our analysis of management options then we would have discarded fire management as an option, even though it can be the best strategy.     

Population management of threatened taxa in captivity within their natural ranges: Lessons from Andean bears (Tremarctos ornatus) in Venezuela

Populations of threatened taxa in captivity within their natural ranges can make important contributions to conservation, but these may be compromised by the inappropriate application of population management goals developed in other contexts. We conducted demographic, genetic, and population viability analyses on the captive population of Andean bears (Tremarctos ornatus) in Venezuela to investigate the management of within-range captive populations in general, and to better integrate this population into the conservation of Andean bears in particular. We found that although the present population is very small and not internally self-sustaining, incorporation of confiscated wild individuals has resulted in a low average number of generations in captivity and low inbreeding, with moderate gene diversity and a high probability of future population persistence. However, past imports from extra-range populations have been from over-represented lineages of unknown origin, which have mixed with under-represented Venezuelan ones, reducing the future value of the Venezuelan population as a source for founder stock. Our analyses indicate that the rate of incorporation of wild recruits is a major factor influencing proxy measures of conservation value, and distinguishing within- from extra-range populations. This implies that, contrary to conventional wisdom, internal self-sustainability can be a misguided goal in within-range populations, which furthermore may not be suitable destinations for surplus animals from captive populations elsewhere.     

Water distribution in brine salted cod (Gadus morhua) and salmon (Salmo salar): a low-field 1H NMR study

Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F 相似文献   

Lessons about extinction and translocation: models for eastern barred bandicoots (Perameles gunnii) at Woodlands Historic Park, Victoria, Australia

In 1998 the protected population of Perameles gunnii (eastern barred bandicoot) at Woodlands Historic Park, Victoria, Australia became functionally extinct following removals of individuals for translocation between 1994 and 1996. Population viability analysis and data collected whilst the population was in decline are used to explore the impact that these removals had on the decline of the P. gunnii population at Woodlands. Due to some ambiguities in the life history of P. gunnii at Woodlands, two structurally different population models were used. Explicitly including the removal of animals in the analysis indicates that there may be at least a three-fold increase in the risk of quasiextinction due to removals. In some scenarios, over 17% of the trajectories decrease to a level less than or equal to 10 females within the observed time period of the collapse of the population, that is by April 1998. The modelling approach identified a number of critical factors in the decline of the population, such as variation in survival rates. By representing the life history strategy using two alternate models, quantitative statements about the impact that removals had on the population decline at Woodlands are made. While removals probably contributed to the collapse of the population, removals were not the sole cause of population decline. The real reasons for decline remain unknown; however, it is likely to be closely linked to habitat decline, difficult environmental conditions and predation. If P. gunnii are reintroduced to Woodlands again, then the models presented here may help to develop management strategies to establish a self sustaining population, as well as exploring translocations options.     

Predation of red squirrels by northern goshawks in a conifer forest in northern England: can this limit squirrel numbers and create a conservation dilemma?

Red squirrels (Sciurus vulgaris) have been lost from most broadleaved habitats in England due to the range expansion of grey squirrels (S. carolinensis). Currently, the main refugia for red squirrels in England are the extensive exotic conifer forests in the north. These forests are also home to an expanding population of northern goshawks (Accipiter gentilis) that were re-established in the 1970s. During the breeding season (March - August), goshawks feed mainly on birds, with species of Columbidae, Corvidae and Phasianidae/Tetraonidae comprising 79% of 5445 prey items collected during 1973-1996. Only 97 red squirrels were recorded in this sample. We estimated that ca. 79 red squirrels were removed by goshawks each breeding season in Kielder Forest, but there was much annual variation (8-261 squirrels predated) that appeared to be related to the masting frequency of Norway spruce (Picea abies). Goshawks were likely to remove fewer squirrels outside the breeding season (September-February) because only adult males overwintered in the study area. Based on the area of conifers of a cone-bearing age and known densities of squirrels, we estimated that 1294-5556 adult squirrels produced 2135-9167 offspring annually in Kielder. For goshawks to reduce the population growth rate of squirrels to zero, predation would have to exceed 50% of the population. Clearly, this does not appear to be the case. This conclusion is in broad agreement with other studies indicating that food availability (conifer seed) is the main factor limiting numbers of tree squirrels, not predation. Thus, existing conservation management for sympatric populations of red squirrels and goshawks are compatible.     

Life history attributes of the threatened Australian snake (Stephen's banded snake Hoplocephalus stephensii, Elapidae)

Whether or not a species is threatened by habitat change is influenced by its life-history traits as well as by the nature and severity of the threatening process. Detailed studies of declining taxa can clarify reasons for their vulnerability, both in proximate terms (e.g., taxa with slow growth, delayed maturation, low fecundity and infrequent reproduction will be poorly suited to withstand increases in adult mortality rates) and in an evolutionary perspective (i.e., what attributes of the environment have favoured the evolution of certain life history traits?). We obtained data on life history traits during an intensive radio-tracking study on the threatened arboreal elapid snake Hoplocephalus stephensii from forest habitats of eastern Australia. Based on 39 field-collected specimens, these long, slender snakes (mean adult snout-vent length 73 cm, mass 114 g) feed predominantly on mammalian prey such as Bush Rats (Rattus fuscipes) and Pygmy-possums (Cercartetus nanus); but juveniles also take lizards. Foraging modes are diverse, from active searching through to ambush. Gape-limitation prevents snakes from ingesting adults of the most abundant local rodent (R. fuscipes), limiting the snakes to specialise on sub-adult rats which are only seasonally available. Rates of feeding, growth and reproduction are low; for example, none of 21 wild-caught females was reproductive. However, snakes given access to abundant prey in captivity, rapidly gained in body condition, grew significantly, and subsequently reproduced. Litters consisted of a few (1-9), relatively large (25 cm snout-vent length, 7.5 g) offspring. The “slow” life-history traits that have contributed to endangerment of this taxon may include proximate as well as evolutionary responses to the low temperatures and limited prey availability in the forest habitat of H. stephensii.