Reintroduction Sites Research Articles

A recovery network leads to the natural recolonization of an archipelago and a potential trailing edge refuge.

Rapid environmental change is reshaping ecosystems and driving species loss globally. Carnivore populations have declined and retracted rapidly and have been the target of numerous translocation projects. Success, however, is complicated when these efforts occur in novel ecosystems. Identifying refuges, locations that are resistant to environmental change, within a translocation framework should improve population recovery and persistence. American martens (Martes americana) are the most frequently translocated carnivore in North America. As elsewhere, martens were extirpated across much of the Great Lakes region by the 1930s and, despite multiple translocations beginning in the 1950s, martens remain of regional conservation concern. Surprisingly, martens were rediscovered in 2014 on the Apostle Islands of Lake Superior after a putative absence of >40yr. To identify the source of martens to the islands and understand connectivity of the reintroduction network, we collected genetic data on martens from the archipelago and from all regional reintroduction sites. In total, we genotyped 483 individual martens, 43 of which inhabited the Apostle Islands (densities 0.42-1.46km-2 ). Coalescent analyses supported the contemporary recolonization of the Apostle Islands with progenitors likely originating from Michigan, which were sourced from Ontario. We also identified movements by a first-order relative between the Apostle Islands and the recovery network. We detected some regional gene flow, but in an unexpected direction: individuals moving from the islands to the mainland. Our findings suggest that the Apostle Islands were naturally recolonized by progeny of translocated individuals and now act as a source back to the reintroduction sites on the mainland. We suggest that the Apostle Islands, given its protection from disturbance, complex forest structure, and reduced carnivore competition, will act as a potential refuge for marten along their trailing range boundary and a central node for regional recovery. Our work reveals that translocations, even those occurring along southern range boundaries, can create recovery networks that function like natural metapopulations. Identifying refuges, locations that are resistant to environmental change, within these recovery networks can further improve species recovery, even within novel environments. Future translocation planning should a priori identify potential refuges and sources to improve short-term recovery and long-term persistence.

Comparative studies on the stress responses of two Bupleurum (Apiaceae) species in support of conservation programmes

Bupleurum tenuissimum is a rare species in Spain, which became extinct in recent decades in many localities, including protected areas. In the study area, the 'Albufera' Natural Park (SE Spain), the species was present in Limonietalia grasslands, a priority and endangered habitat, but has not been observed in the last 40 years. At present, it is included in conservation programmes aimed at its reintroduction in this territory. This study's primary objective was to establish the limits of tolerance of this species to salt and water stress under controlled greenhouse conditions. A congeneric species, B. fruticousm, was included as comparative material to get insights into its stress response mechanisms. Analysis of changes in growth parameters (stem length, number of leaves, root length, fresh weight and water content of roots and leaves) in response to the applied stress treatments confirmed that B. tenuissimum behaves as a facultative (moderate) halophyte susceptible to drought stress, whereas B. fruticosum is not severely affected by water stress but is sensitive to salinity, even at low NaCl concentrations. The stress-induced changes in several biochemical parameters (contents of photosynthetic pigments, ions, osmolytes, oxidative stress markers, and non-enzymatic antioxidant compounds, and specific activities of relevant antioxidant enzymes) explained the differential behaviour of the investigated Bupleurum species. In addition to the novelty of these findings in a genus that has rarely been studied from this perspective, these results will be relevant for implementing and managing B. tenuissimum conservation programmes, guiding the selection of reintroduction sites. The study also provides valuable information on the stress tolerance of B. fruticosum, with great potential for the ecological restoration of Mediterranean dry forest vegetation and riparian thickets.

Distribution patterns of the native Eurasian and the non-native North American beaver in Finland\u2014possible factors affecting the slow range expansion of the native species

Distribution patterns of species are affected by resource availability, dispersal, disturbance and population dynamics. The smaller population size and range of the native Eurasian beaver (Castor fiber) compared to the non-native North American beaver (Castor canadensis) in Finland raise questions on reasons for the slower range expansion of the native species. We compared the population growth rates and the spread of both species from their release sites. We also studied the factors possibly affecting the spread of the Eurasian beaver in South western Finland in more detail. We found that the North American beaver has spread longer distances than the Eurasian beaver, but we did not find evidence for movement barriers constraining the expansion rate of the native species. Lack of high-quality habitats does not seem to constrain the expansion to nearby areas either. Despite this, the Eurasian beaver population has grown to a high density close to its reintroduction site, and it has started to spread to novel areas only recently. We conclude that the expansion of the native beaver in Finland seems to be controlled by factors other than those related to barriers for movement: movement behavior and population dynamics, which require further investigation.

Evaluation of threats faced by the Amur leopards in their native habitat and identification of suitable sites for re-introduction into the wild using GIS

Evaluation of threats faced by the Amur leopards in their native habitat and identification of suitable sites for re-introduction into the wild using GIS

Individual-based seasonal habitat selection in a forest-dwelling population of reintroduced bison Bison bison

Mapping habitat selection by threatened species provides critical information for conservation planning. For reintroduced populations, understanding habitat selection is also necessary to predict dispersal and inform selection of new reintroduction sites. Efforts to restore bison Bison bison to the boreal forest hinge on the persistence of geographically isolated populations that occupy diverse landscapes, and for many populations selected habitats are unknown. We used location data from GPS-collared bison to develop seasonal resource selection function (RSF) models and predictive maps for the reintroduced ‘Nahanni’ population. We accounted for variation in individual behaviour by calculating averaged population-level selection coefficients from individual RSFs, and we compared these results to a pooled RSF from all bison. Individual RSFs revealed variation in habitat selection that was not always captured by the pooled RSF, although there were some consistencies. Bison strongly selected forage-rich graminoid-dominated wetlands (fens) during winter, but less so in summer when there were potential tradeoffs with poor footing and biting flies. In summer, bison selected alternative sources of forage such as herbaceous, shrubby and fluvial habitats (i.e. riverine islands and gravel bars). The observed association with fluvial habitat may be an adaptation to low forage availability on this landscape. Bison also selected roads and anthropogenic clearings associated with resource development, demonstrating potential for human–wildlife conflict. Our predictive maps highlight areas of conservation interest, and should be considered in land use planning and environmental assessments. We demonstrate the value of foraging habitat for forest-dwelling bison, particularly in winter. Identifying forage-rich habitat patches, and connectivity between them, is important when considering sites for new reintroductions or expansion of existing populations. More broadly, our approach may be used to identify areas of high conservation interest, where resources do not allow extensive sample sizes of GPS-collared animals.

Preventing Extinction of a Critically Endangered Dactylorhiza incarnata subsp. ochroleuca in Britain Using Symbiotic Seedlings for Reintroduction.

The yellow early marsh-orchid (Dactylorhiza incarnata subsp. ochroleuca) is critically endangered in the UK. Reintroduction of this threatened orchid to former haunts that have been restored is a long-term objective of this study. Identifying germination-specific mycorrhizal fungus lineages from closely related species is used as a method due to the extremely small number of plants left in the wild. A putative orchid mycorrhizal fungus of the family Tulasnellaceae, isolated from Dactylorhiza praetermissa, supported in vitro seed germination to produce reintroduction-ready seedlings. Reintroduced symbiotic seedlings survived over the winter months in the flooded reintroduction site (RS). The comparative soil analysis for key nutrients before reintroduction showed that phosphorus content in the RS is very low compared to the soil collected from the wild site (WS) where the last viable population exists. On the other hand, C:N ratio in the soil at the WS and RS were not significantly different. To our knowledge, this is the first-ever report on the reintroduction of symbiotic seedlings of a threatened orchid back to the wild in the UK.

Assessing species reintroduction sites based on future climate suitability for food resources.

The reintroduction of a species that is extinct in the wild demands caution because reintroduction locations may be associated with threats, such as hunting, poor-quality habitat, and climate change. This is the case for Cyanopsitta spixii (Spix's Macaw), which has been extinct in the wild since 2000. The few living individuals were created in captivity and will be used in a reintroduction project within the species' original distribution area, the Caatinga domain (Brazil). Because the occurrence records for this bird are old and inaccurate, we investigated the current and future environmental suitability of the 14 plant species used by C. spixii as resource. These plants are key elements for the long-term reestablishment of the species in the wild, so the use of models helps in the assessment of the effects of climate change on the availability of these resources for the species and informs selection of the best places for reintroduction. We based our models of environmental suitability on 19 bioclimatic variables and nine physical soil and topography variables. Climate projections were created for the present and for the year 2070 with an optimistic (SSP2-4.5) and a pessimistic (SSP5-8.5) climate scenario. Both future climate scenarios lead to a reduction in area of environmental suitability that overlapped for all the plant species: 33% reduction for SSP2-4.5 and 63% reduction for SSP5-8.5. If our projections materialize, climate change could thus affect the distribution of key resources, and the maintenance of C. spixii would depend on restoration of degraded areas, especially riparian forests, and the preservation of already existing natural areas. The Caatinga domain is very threatened by habitat loss and, for the success of this reintroduction project, the parties involved must act to protect the species and the resources it uses.

Estimating the Suitability for the Reintroduced Arabian Oryx (Oryx leucoryx, Pallas 1777) of Two Desert Environments by NIRS-Aided Fecal Chemistry

The re-introduction paradigm is that Arabian Oryx (Oryx leucoryx) herds adjust the size of their home ranges depending on the availability of vegetation, which is directly related to rainfall. In Israel, Arabian oryx were released in two hyper-arid sites: the Arava Valley and in the Paran wilderness, belonging to the Sudanese and the Saharo–Arabian biogeographic zones, respectively. While post-release survival was similar in both, reproductive success in the Paran wilderness reintroduction site was extremely low, resulting in an acute decline of the reintroduced population over time. The hypothesis that impaired nutrition might be associated with this finding was assessed with near-infrared spectroscopy (NIRS)-aided chemistry of monthly sampled fecal pellets, used as remote sensing evidence of ingested diets, throughout a year. Fecal nitrogen (FN), used as an estimate of nutritional status, was consistently higher in the Arava. Grass was never the sole or even a major dietary component. The dietary contribution of tannin-rich browse was high and steady all year-round in the Arava and increased steadily in Paran from winter to summer, corresponding to the period of availability of Acacia raddiana pods in both regions. The oryx in Paran had a home-range that was ten-fold, compared to the Arava, suggesting less feed availability. Acacia browsing may mitigate the effects of temporal variance in primary production. Under such conditions, oryx should be preferably released in areas that support significant acacia stands.

Use of a spatially explicit individual-based model to predict population trajectories and habitat connectivity for a reintroduced ursid

AbstractReintroductions of large carnivore species present unique opportunities to model population dynamics as populations can be monitored from the beginning of a reintroduction. However, analysis of the population dynamics of such reintroduced populations is rare and may be limited in incorporating the complex movements and environmental interactions of large carnivores. Starting in 2004, Asiatic black bears Ursus thibetanus were reintroduced and tracked in the Republic of Korea, along with their descendants, using radio telemetry, yielding 33,924 tracking points over 12 years. Along with information about habitat use, landscape, and resource availability, we estimated the population equilibrium and dispersal capability of the reintroduced population. We used a mixed modelling approach to determine suitable habitat areas, population equilibria for three different resources-based scenarios, and least-cost pathways (i.e. corridors) for dispersal. Our population simulations provided a mean population equilibrium of 64 individuals at the original reintroduction site and a potential maximum of 1,438 individuals in the country. The simulation showed that the bear population will disperse to nearby mountainous areas, but a second reintroduction will be required to fully restore U. thibetanus. Northern suitable habitats are currently disconnected and natural re-population is unlikely to happen unless supported. Our methodologies and findings are also relevant for determining the outcome and trajectories of reintroduced populations of other large carnivores.

Consequences of the reintroduction of regionally extinct mammals for vegetation composition and structure at two established reintroduction sites in semi‐arid Australia

AbstractAustralia has lost a substantial proportion of its small to medium‐sized mammals since European colonisation. Given the passage of time since local extinctions – decades to more than a century for much of the continent – the consequences of these changes for vegetation are poorly known. In this study, we take advantage of two well‐established mammal reintroduction projects in southern inland Australia to examine the ecological consequences for vegetation of re‐established mammal populations. The study is based on replicated surveys inside and outside fenced reintroduction sites, with treatments characterised by varying presence, absence and composition of reintroduced mammals, feral predators and feral herbivores. We found a suite of differences in vegetation between reintroduction sites and matched controls, with generally lower richness inside reintroduction sites (with one exception). Other compositional differences varied by location, with some functional groups – herbaceous chenopods, shrubby chenopods, introduced geophytes and low shrubs – and a few individual chenopod species – being less frequent inside the reintroduction site at one location. At the same site, mistletoes and orchids were less abundant inside than outside the reintroduction site. Structural differences included a higher percentage of bare ground inside, and a higher ground layer for one inside treatment versus outside. Although the absence of baseline data and replicated temporal data limits inference as to causal factors, many of the results are consistent with data from other reintroduction sites. Some results, especially those for geophytes, mistletoes and some chenopods, may indicate long‐term consequences for those taxa. Whilst predator‐fencing substantially contributes to prevention of extinction of highly threatened mammals, some environmental trade‐offs are inevitable. Nonetheless, given the aims of reintroductions include re‐constructing natural ecosystem processes, the resulting changes to vegetation require ongoing investigation and further monitoring.

Species distribution models for conservation planning in fire‐prone landscapes

Species distribution models are an essential tool for biodiversity conservation, with important applications such as spatial prioritisation of conservation actions and elucidating relationships between environmental predictors and species responses. These models are most useful to conservation managers when they include factors that can be readily manipulated, such as fire. In this study, we collated a comprehensive dataset of mammal records from a fire-prone region in south-east Australia where mammals have suffered declines in recent decades. We used species distribution modelling to (1) determine the relative influence of climate, fire, vegetation and topography on ground-dwelling mammal distributions; (2) determine species responses to time since fire, and; (3) provide spatial predictions of habitat suitability for conservation planning. Climate was the predominant driver of habitat suitability for most species, although other factors were influential in some cases. Time since fire was an important factor driving the distribution of only two of 16 modelled species which were more likely to be recorded in recently burnt vegetation. Habitat suitability varied spatially among species however multi-species habitat suitability was highest in the drier and hotter eastern section of the landscape, highlighting a key area for conservation efforts. The outputs from our models can be used for practical conservation actions such as finding new populations or identifying sites for reintroductions. We conclude that presence-only species distribution models are useful for determining species fire responses, complementing more systematic methods, and that including dynamic variables, such as time since fire, can increase their conservation relevance.

An attempt to estimate the habitat capacity of reintroduction sites for the forest reindeer in the Nizhny Novgorod region

The article is the first attempt to consider the consumption of food supply by the European subspecies of the reindeer (Rangifer tarandus tarandus) during reintroduction in the central part of the Russian Plain on the territory of the Kerzhensky State Reserve in the Nizhny Novgorod Region. On the territory of the adaptation enclosure (122.44 ha), the vegetation was examined in 2015-16 (before the release of deer) and the changes that have occurred over 2 years of keeping animals (2018-20). The enclosure was used by animals for 5776 deer-days, including 3756 summer days and 2020 winter days. It was found that the area of the adaptation enclosure is fully used by the reindeer. Summer food supply have not changed, but a significant degradation of the lichen layer has been revealed. It was shown that the use of lichens by deer for food during the snowless period is minimal. Lichens of the genus Cladonia are the main food for reindeer after the formation of the snow cover. Winter food supply is the limiting factor that determines the habitat capacity. During the 2020 winter reindeer days, 60.02 tons of lichens were used. The daily consumption of lichens by one deer was 29.71 kg. It is shown that the number of deer kept in the adaptation enclosure exceeds the habitat capacity. The possibilities of keeping different numbers of animals with and without winter feeding have been estimated. The area of winter pastures necessary for a reindeer is calculated: 26.94 hectares of natural reindeer lichen communities, or 14.32 hectares in terms of 100% lichen coverage. These data can be used to calculate the potential capacity of reindeer habitats in forest-swamp complexes of the central part of the Russian Plain

Use of genetic tools to assess predation on reintroduced howler monkeys (Alouatta caraya) in Northeastern Argentina.

Despite strong support from the media, the reintroduction of animals into natural environments does not always achieve its goal. Alouatta caraya is the primate species facing the greatest hunting pressure due to the illegal pet trade in Argentina. Confiscations of this species are common, as is the voluntary surrender of animals by owners no longer able or willing to care for them. These animals ultimately arrive at rehabilitation centers and, in many cases, are released into natural environments that may differ from the original sites where they were captured. Until recently, the lack of genetic analysis of the individuals involved led to biased relocation decisions. We followed the reintroduction of 12 A. caraya individuals in a protected area (Isla Palacio, Misiones, Argentina). The presence of potential predators such as pumas (Puma concolor) and jaguars (Panthera onca) in this area was confirmed by camera traps, footprints and feces. After the disappearance of four A. caraya at the reintroduction site, we investigated the applicability of genetic assignment tests based on genotypic data to accurately identify predated individuals. Genetic analyses allowed us to determine the predator species (P. onca) and to identify the predated individuals as two of the reintroduced animals. This procedure is promising for identifying the remains of predated individuals, and can contribute to the design of reintroduction policies based on scientific evidence.

Phytosociological and niche distribution study of Paris polyphylla smith, an important medicinal herb of Indian Himalayan region

The prediction of species distribution is emerging as an important tool for conservation and rehabilitation planning of economically important plant species including medicinal and aromatic plants. Paris polyphylla, an economically and high valued medicinal plant of Indian Himalayan Region (IHR) is reported to lose its habitat area due to over-exploitation. In this study, attempts were made to understand vegetation pattern and find the potential distribution of Paris polyphylla, using MaxEnt in Pindar Valley (2000–4000 m ASL), Bageshwar district of Uttarakhand state, India. MaxEnt is a machine learning data mining technique that estimates a species distribution by finding the distribution of maximum entropy, based on existing knowledge. Phytosociological studies revealed the varying density of target species ranging from 0.50 ind/m2 (P1; 2000 m asl) to 2.00 ind/m2 (P6; 2500 m asl). Among the different geographical provinces of Uttarakhand, MaxEnt predicted wider potential distribution of P. polyphylla in temperate forest with an overall estimated area of 790.85 km2 as suitable. It was found that Precipitation, Elevation and Vegetation type were the most important variables for predicting the habitat suitability. Dwali (ca. 2500 m ASL) site was predicted as a potential distribution area of P. polyphylla with ground-based validation and further suggested this area as a potential reintroduction site. The results of this study can be used to plan protection and re-introduction of P. polyphylla in the region. MaxEnt approach is thus a very promising tool in species conservation planning and in predicting the potential distribution of other high valued medicinal plants of IHR.

Using dermal glucocorticoids to determine the effects of disease and environment on the critically endangered Wyoming toad.

Amphibian populations are declining worldwide, and increased exposure to environmental stressors, including global climate change and pathogens like Batrachochytrium dendrobatidis (Bd), may be contributing to this decline. Our goal was to use a novel dermal swabbing method to measure glucocorticoid (GC) hormones and investigate the relationship among disease and environmental conditions in the critically endangered Wyoming toad (Anaxyrus baxteri). Our objectives were to (i) validate the use of dermal swabs to measure GCs using an adrenocorticotropic hormone (ACTH) challenge on eight captive toads (4 ACTH: 2 M, 2F and 4 saline as a control: 2 M, 2F), (ii) investigate stress physiology and disease status of toads across six reintroduction sites and (iii) compare dermal cortisol between reintroduced and captive toads. Dermal cortisol peaked immediately after the ACTH and saline injections. Faecal GC metabolites (FGMs) were significantly higher one week after the ACTH injection compared with the week before. Saline-injected toads had no change in FGM over time. Toads were only found in three reintroduction sites and dermal cortisol was similar across sites; however, reintroduced toads had higher dermal cortisol in August compared with June and compared with captive individuals. Bd status did not influence dermal cortisol concentrations. Dermal and faecal hormonal metabolite analyses can be used to study amphibian stress physiology and learn how environmental conditions are impacting population success.

Reintroducing species when threats still exist: assessing the suitability of contemporary landscapes for island endemics

AbstractReintroducing species into landscapes with persistent threats is a conservation challenge. Although historic threats may not be eliminated, they should be understood in the context of contemporary landscapes. Regenerating landscapes often contain newly emergent habitat, creating opportunities for reintroductions. The Endangered St Croix ground lizard Pholidoscelis polops was extirpated from the main island of St Croix, U.S. Virgin Islands, as a result of habitat conversion to agriculture and predation by the small Indian mongoose Herpestes auropunctatus. The species survived on two small cays and was later translocated to two islands. Since the 1950s, new land-cover types have emerged on St Croix, creating a matrix of suitable habitat throughout the island. Here we examined whether the new habitat is sufficient for a successful reintroduction of the St Croix ground lizard, utilizing three complementary approaches. Firstly, we compared a map from 1750 to the current landscape of St Croix and found statistical similarity of land-cover types. Secondly, we determined habitat suitability based on a binomial mixture population model developed as part of the programme monitoring the largest extant population of the St Croix ground lizard. We estimated the habitat to be sufficient for > 142,000 lizards to inhabit St Croix. Thirdly, we prioritized potential reintroduction sites and planned for reintroductions to take place during 2020–2023. Our case study demonstrates how changing landscapes alter the spatial configuration of threats to species, which can create opportunities for reintroduction. Presuming that areas of degraded habitat may never again be habitable could fail to consider how regenerating landscapes can support species recovery. When contemporary landscapes are taken into account, opportunities for reintroducing threatened species can emerge.

Reintroduction of Groenlandia densa (L.) Fourr. – experiences and suggestions

Abstract Groenlandia densa (L.) Fourr. is a native species in Poland of evergreen hydromacrophyte occurring in water-sources or groundwater-fed watercourses. It is a critically endangered taxon which requires active protection. To increase the chance of preserving G. densa population in Western Pomerania, this plant was introduced to the Grabowa and Radew river systems in the Natura 2000 areas PLH 320022 “Radew, Chociela and Chotla Valley” and PLH 320003 “Grabowa Valley”, on a total of 33 sites. In the Radew and its tributaries (Chociel, Zgniła Struga), 6 out of 20 sites were maintained, where reintroduction was successful, while in the Grabowa and its tributaries (Błotnica, Biegała), only 3 out of 13 reintroduction sites survived, and reintroduction in the remaining ones did not bring expected results. Favorable conditions for G. densa were found in initial stages of Beruletum submersae Roll 1938 plant community.

Assessing conservation attitudes and behaviors of Congolese children neighboring the world's first bonobo (Pan paniscus) release site.

Poaching and habitat destruction in the Congo Basin threaten African great apes including the bonobo (Pan paniscus), chimpanzees (Pan troglodytes), and gorillas (Gorilla spp.) with extinction. One way to combat extinction is to reintroduce rescued and rehabilitated apes and repopulate native habitats. Reintroduction programs are only successful if they are supported by local populations. Ekolo ya Bonobo, located in Equateur province of the Democratic Republic of Congo (DRC), is the world's only reintroduction site for rehabilitated bonobos. Here we assess whether children, of the Ilonga-Pôo, living adjacent to Ekolo ya Bonobo demonstrate more pro-ape conservation attitudes than children living in, Kinshasa, the capital city. We examined children's attitudes toward great apes because children are typically the focus of conservation education programs. We used the Great Ape Attitude Questionnaire to test the Contact Hypothesis, which posits that proximity to great ape habitat influences pro-conservation attitudes toward great apes. Ilonga-Pôo children who live in closer contact with wild bonobos felt greater responsibility to protect great apes compared to those in Kinshasa who live outside the natural habitat of great apes. These results suggest that among participants in the DRC, spatial proximity to a species fosters a greater sense of responsibility to protect and conserve. These results have implications for the successful implementation of great ape reintroduction programs in the Congo Basin. The data analyzed in this study were collected in 2010 and therefore provide a baseline for longitudinal study of this reintroduction site.

Modeling the geographic distribution of pawpaw (Asimina triloba [L.] Dunal) in a portion of its northern range limits, western New York State, USA

Pawpaw (Asimina triloba [L.] Dunal) is a small deciduous tree in eastern North America notable for its edible fruit. Its northern range extends into New York State (NYS) where it is listed as threatened, with only approximately 20 sites known to contain pawpaw. This research models the geographic distribution of pawpaw in western NYS (land area = 27,263 km2) for four reasons: to understand factors shaping its distribution, to assess the degree to which it is protected, to locate potential introduction or reintroduction sites, and to locate potential sites with undiscovered pawpaw. This study uses an ensemble of small models (ESM) approach devised for modeling the distribution of rare species, which averages predictions from simple (i.e., bivariate) models weighted by model predictive performance. The ESM in this study, constructed from boosted regression tree (BRT) models, demonstrated a high ability to discern pawpaw presences from pseudo-absences. The area under the receiver operating characteristic curve (AUC) value was 0.986 when calculated using training data, and BRT models comprising the ESM exhibited AUC values calculated using cross-validation data as high as 0.957. The ESM suggests that pawpaw is found in the warmest (mean annual temperature > 9.0 °C,) and driest (May–September precipitation 110 cm) soils. Locations predicted to be suitable for pawpaw are overwhelmingly found on unprotected lands; forested areas in PAs with “high” or “highest” suitability for pawpaw only comprise 0.1–0.2% of the study area.

Modeling Louisiana Pinesnake Habitat to Guide the Search for Population Relicts

Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Efforts to refine existing habitat models that help locate relictual populations and identify potential reintroduction sites are needed. To validate these models, more efficient methods of detection for this rare species must also be developed. Here we expand recent habitat suitability models based on edaphic factors to include mature Pinus (pine) stands that have not been cut for at least 30 years and likely have vegetation structure with the potential to support the species. Our model identified a total of 1652 patches comprising 180,050 ha of potentially suitable habitat, but only 16 (1%) of these patches were more than 1000 ha and considered worthy of conservation attention as potential reintroduction sites. We also visited potentially suitable habitat, as determined by our model, and used camera traps to survey for relictual populations at 7 areas in Texas. We observed 518 snakes of 18 species in 8,388,078 images taken from April to October 2016, but no Louisiana Pinesnakes were detected. The patchiness of the habitat model and failure to detect Louisiana Pinesnakes corroborate independent conclusions that most populations of the species are small, isolated, probably in decline, and possibly extirpated. In the context of this extreme rarity, we believe this study will help manage limited conservation resources by narrowing the search areas for relictual populations, providing a more cost-effective method of surveying those areas, and identifying the best sites for future reintroduction efforts.