Population and geographic range dynamics: implications for conservation planning

Continuing downward trends in the population sizes of many species, in the conservation status of threatened species, and in the quality, extent and connectedness of habitats are of increasing concern. Identifying the attributes of declining populations will help predict how biodiversity will be impacted and guide conservation actions. However, the drivers of biodiversity declines have changed over time and average trends in abundance or distributional change hide significant variation among species. While some populations are declining rapidly, the majority remain relatively stable and others are increasing. Here we dissect out some of the changing drivers of population and geographic range change, and identify biological and geographical correlates of winners and losers in two large datasets covering local population sizes of vertebrates since 1970 and the distributions of Galliform birds over the last two centuries. We find weak evidence for ecological and biological traits being predictors of local decline in range or abundance, but stronger evidence for the role of local anthropogenic threats and environmental change. An improved understanding of the dynamics of threat processes and how they may affect different species will help to guide better conservation planning in a continuously changing world.     

Quantifying the spatial ecology of wide-ranging marine species in the Gulf of California: implications for marine conservation planning

There is growing interest in systematic establishment of marine protected area (MPA) networks and representative conservation sites. This movement toward networks of no-take zones requires that reserves are deliberately and adequately spaced for connectivity. Here, we test the network functionality of an ecoregional assessment configuration of marine conservation areas by evaluating the habitat protection and connectivity offered to wide-ranging fauna in the Gulf of California (GOC, Mexico). We first use expert opinion to identify representative species of wide-ranging fauna of the GOC. These include leopard grouper, hammerhead sharks, California brown pelicans and green sea turtles. Analyzing habitat models with both structural and functional connectivity indexes, our results indicate that the configuration includes large proportions of biologically important habitat for the four species considered (25-40%), particularly, the best quality habitats (46-57%). Our results also show that connectivity levels offered by the conservation area design for these four species may be similar to connectivity levels offered by the entire Gulf of California, thus indicating that connectivity offered by the areas may resemble natural connectivity. The selected focal species comprise different life histories among marine or marine-related vertebrates and are associated with those habitats holding the most biodiversity values (i.e. coastal habitats); our results thus suggest that the proposed configuration may function as a network for connectivity and may adequately represent the marine megafauna in the GOC, including the potential connectivity among habitat patches. This work highlights the range of approaches that can be used to quantify habitat protection and connectivity for wide-ranging marine species in marine reserve networks.     

Downscaling patterns of complementarity to a finer resolution and its implications for conservation prioritization

Given species inventories of all sites in a planning area, integer programming or heuristic algorithms can prioritize sites in terms of the site's complementary value, that is, the ability of the site to complement (add unrepresented species to) other sites prioritized for conservation. The utility of these procedures is limited because distributions of species are typically available only as coarse atlases or range maps, whereas conservation planners need to prioritize relatively small sites. If such coarse‐resolution information can be used to identify small sites that efficiently represent species (i.e., downscaled), then such data can be useful for conservation planning. We develop and test a new type of surrogate for biodiversity, which we call downscaled complementarity. In this approach, complementarity values from large cells are downscaled to small cells, using statistical methods or simple map overlays. We illustrate our approach for birds in Spain by building models at coarse scale (50 × 50 km atlas of European birds, and global range maps of birds interpreted at the same 50 × 50 km grid size), using this model to predict complementary value for 10 × 10 km cells in Spain, and testing how well‐prioritized cells represented bird distributions in an independent bird atlas of those 10 × 10 km cells. Downscaled complementarity was about 63–77% as effective as having full knowledge of the 10‐km atlas data in its ability to improve on random selection of sites. Downscaled complementarity has relatively low data acquisition cost and meets representation goals well compared with other surrogates currently in use. Our study justifies additional tests to determine whether downscaled complementarity is an effective surrogate for other regions and taxa, and at spatial resolution finer than 10 × 10 km cells. Until such tests have been completed, we caution against assuming that any surrogate can reliably prioritize sites for species representation.     

Maximizing species conservation in continental Ecuador: a case of systematic conservation planning for biodiverse regions

Ecuador has the largest number of species by area worldwide, but also a low representation of species within its protected areas. Here, we applied systematic conservation planning to identify potential areas for conservation in continental Ecuador, with the aim of increasing the representation of terrestrial species diversity in the protected area network. We selected 809 terrestrial species (amphibians, birds, mammals, and plants), for which distributions were estimated via species distribution models (SDMs), using Maxent. For each species we established conservation goals based on conservation priorities, and estimated new potential protected areas using Marxan conservation planning software. For each selected area, we determined their conservation priority and feasibility of establishment, two important aspects in the decision-making processes. We found that according to our conservation goals, the current protected area network contains large conservation gaps. Potential areas for conservation almost double the surface area of currently protected areas. Most of the newly proposed areas are located in the Coast, a region with large conservation gaps and irreversible changes in land use. The most feasible areas for conservation were found in the Amazon and Andes regions, which encompass more undisturbed habitats, and already harbor most of the current reserves. Our study allows defining a viable strategy for preserving Ecuador''s biodiversity, by combining SDMs, GIS-based decision-support software, and priority and feasibility assessments of the selected areas. This approach is useful for complementing protected area networks in countries with great biodiversity, insufficient biological information, and limited resources for conservation.     

Parasite phylogeographical congruence with salmon host evolutionarily significant units: implications for salmon conservation

Comparative phylogeographical studies between parasites and their hosts or with biogeographical regions are useful to predict parasite dispersal potential over a broad geographical range. We used both microsatellite markers and mtDNA sequence data from a trematode parasite, Plagioporus shawi, to test for congruence across two evolutionarily significant unit (ESU) boundaries of its salmonid hosts (Oncorhynchus spp.). We find congruent patterns with the nuclear loci of P. shawi and the ESU boundaries of its salmonid hosts. This pattern indicates that broad-scale phylogeographical patterns of a parasite can be predicted by the biogeographical history of their hosts. Furthermore, this pattern provides independent support for these ESU boundaries as biologically relevant barriers. The mtDNA shows some discordance with nuclear loci and a level of genetic differentiation greater than can be explained by genetic drift. Thus, the mtDNA cannot be used in isolation to infer the population history of P. shawi. The genetic differentiation at both the nuclear and mtDNA markers will be useful for salmon fisheries management by providing a tool to assign ocean-migrating salmonids back to their freshwater population of origin.     

Birdsong and anthropogenic noise: implications and applications for conservation

The dramatic increase in human activities all over the world has caused, on an evolutionary time scale, a sudden rise in especially low-pitched noise levels. Ambient noise may be detrimental to birds through direct stress, masking of predator arrival or associated alarm calls, and by interference of acoustic signals in general. Two of the most important functions of avian acoustic signals are territory defence and mate attraction. Both of these functions are hampered when signal efficiency is reduced through rising noise levels, resulting in direct negative fitness consequences. Many bird species are less abundant near highways and studies are becoming available on reduced reproductive success in noisy territories. Urbanization typically leads to homogenization of bird communities over large geographical ranges. We review current evidence for whether and how anthropogenic noise plays a role in these patterns of decline in diversity and density. We also provide details of a case study on great tits (Parus major), a successful urban species. Great tits show features that other species may lack and make them unsuitable for city life. We hypothesize that behavioural plasticity in singing behaviour may allow species more time to adapt to human-altered environments and we address the potential for microevolutionary changes and urban speciation in European blackbirds (Turdus merula). We conclude by providing an overview of mitigating measures available to abate noise levels that are degrading bird breeding areas. Bird conservationists probably gain most by realizing that birds and humans often benefit from the same or only slightly modified measures.     

乡土植物生活型构成对川渝地区边坡植被水土保持效益的影响

乡土植物灌木化建植是高速公路边坡防护的重要生态模式。为了探讨生态恢复过程中乡土植物的生活型构成对边坡植被水土保持效益的影响,揭示乡土植物生活型-物种多样性-生态系统功能间的偶合关系,借助3个物种配置试验,于2009年4月构建了以草本、灌木或乔木为主体的草本型、灌木型、乔木型绿化配置及草-灌-乔混合型试验区。自建植次年(2010年)起,对试验区进行持续5a生态监测。结果表明:1)边坡植被的物种丰富度与乡土植物的生活型有关,呈现乔木型灌木型草-灌-乔混合型草本型趋势;2)植被的物种多样性(Shannon-Wiener指数、Pielou指数)与乡土植物生活型构成及建植年限有关:建植后第1、第2年,多样性水平呈草本型草-灌-乔混合型灌木型乔木型变化趋势;自建植后第三起(2012—2014年),呈草-灌-乔混合型草本型灌木型乔木型波动;3)植被的水土保持性能(径流系数、侵蚀模数)与群落的物种多样性密切相关:多样性水平越高,水土保持性能越强。可见,乡土植物的生活型构成对提高边坡植被的物种多样性、改善生态性能至关重要。     

Relative need for conservation assessments of vascular plant species among ecoregions

Aim (1) To determine the relative need for conservation assessments of vascular plant species among the world’s ecoregions given under‐assessed species distributions; (2) to evaluate the challenge posed by the lack of financial resources on species assessment efforts; and (3) to demonstrate the utility of nonlinear mixed‐effects models with both homoscedastic and heteroscedastic error structures in the identification of species‐rich ecoregions. Location Global. Methods We identified the world’s ecoregions that contain the highest vascular plant species richness after controlling for area using species–area relationship (SAR) models built within a mixed‐effects multi‐model framework. Using quantitative thresholds, ecoregions with the highest plant species richness, historical habitat loss and projected increase in human population density were deemed to be most in need of conservation assessments of plant species. We used generalized linear models to test if countries that overlap with highly important ecoregions are poorer compared with others. Results We classed ecoregions into nine categories based on the relative need for conservation assessments of vascular plant species. Ecoregions of highest relative need are found mostly in the tropics, particularly Southeast Asia, Central America, Tropical Andes and the Cerrado of South America, and the East African montane region and its surrounding areas. Countries overlapping with ecoregions deemed important for conservation assessments are poorer as measured by their capita gross national income than the other countries. The nonlinear mixed modelling framework was effective in reducing residual spatial autocorrelation compared with nonlinear models comprised of only fixed effects. In contrasting multiple SAR models to identify species‐rich ecoregions, there was not one SAR model that fitted best across all biomes. Not all SAR models displayed homoscedastic errors; therefore it is important to consider models with both homoscedastic and heteroscedastic error structures. Main conclusions We propose that conservation assessments should be conducted first in ecoregions with the greatest predicted species richness, historical habitat loss and future human population increase. As ecoregions deemed to be important for conservation assessments are located in the poorest countries, we urge international aid agencies and botanic gardens to cooperate with both local and international scientists to fund and implement conservation assessment programmes there.     

A new method for conservation planning for the persistence of multiple species

Although the aim of conservation planning is the persistence of biodiversity, current methods trade-off ecological realism at a species level in favour of including multiple species and landscape features. For conservation planning to be relevant, the impact of landscape configuration on population processes and the viability of species needs to be considered. We present a novel method for selecting reserve systems that maximize persistence across multiple species, subject to a conservation budget. We use a spatially explicit metapopulation model to estimate extinction risk, a function of the ecology of the species and the amount, quality and configuration of habitat. We compare our new method with more traditional, area-based reserve selection methods, using a ten-species case study, and find that the expected loss of species is reduced 20-fold. Unlike previous methods, we avoid designating arbitrary weightings between reserve size and configuration; rather, our method is based on population processes and is grounded in ecological theory.     

Downscaling European species atlas distributions to a finer resolution: implications for conservation planning

Aim One of the limitations to using species’ distribution atlases in conservation planning is their coarse resolution relative to the needs of local planners. In this study, a simple approach to downscale original species atlas distributions to a finer resolution is outlined. If such a procedure yielded accurate downscaled predictions, then it could be an aid to using available distribution atlases in real‐world local conservation decisions. Location Europe. Methods An iterative procedure based on generalized additive modelling is used to downscale original European 50 × 50 km distributions of 2189 plant and terrestrial vertebrate species to c. 10 × 10 km grid resolution. Models are trained on 70% of the original data and evaluated on the remaining 30%, using the receiver operating characteristic (ROC) procedure. Fitted models are then interpolated to a finer resolution. A British dataset comprising distributions of 81 passerine‐bird species in a 10 × 10 km grid is used as a test bed to assess the accuracy of the downscaled predictions. European‐wide, downscaled predictions are further evaluated in terms of their ability to reproduce: (1) spatial patterns of coincidence in species richness scores among different groups; and (2) spatial patterns of coincidence in richness, rarity and complementarity hotspots. Results There was a generally good agreement between downscaled and observed fine‐resolution distributions for passerine species in Britain (median Jaccard similarity = 70%; lower quartile = 36%; upper quartile = 88%). In contrast, the correlation between downscaled and observed passerine species richness was relatively low (rho = 0.31) indicating a pattern of error propagation through the process of overlaying downscaled distributions for many species. It was also found that measures of model accuracy in fitting original data (ROC) were a poor predictor of models’ ability to interpolate distributions at fine resolutions (rho = ?0.10). Although European hotspots were not fully coincident between observed and modelled coarse‐resolution data, or between modelled coarse resolution and modelled downscaled data, there was evidence that downscaled distributions were able to maintain original cross‐taxon coincidence of species‐richness scores, at least for terrestrial vertebrate groups. Downscaled distributions were also able to uncover important environmental gradients otherwise blurred by coarse‐resolution data. Main conclusions Despite uncertainties, downscaling procedures may prove useful to identify reserves that are more meaningfully related to local patterns of environmental variation. Potential errors arising from the presence of false positives may be reduced if downscaled‐distribution records projected to occur outside the range of original coarse‐resolution data are excluded. However, the usefulness of this procedure may be limited to data‐rich regions. If downscaling procedures are applied to data‐poor regions, then there is a need to undertake further research to understand the structure of error in models. In particular, it would be important to investigate which species are poorly modelled, where and why. Without such an assessment it is difficult to support unsupervised use of downscaled data in most real‐world situations.     

Predicting global abundance of a threatened species from its occurrence: implications for conservation planning

Aim Global abundance is an important characteristic of a species that is correlated with geographical distribution and body size. Despite its importance these estimates are not available since reliable field estimates are either expensive or difficult to obtain. Based on the relationship between a species’ local abundance and distribution, some authors propose that abundance can be obtained through spatial distribution data from maps plotted at different scales. This has never been tested over the entire geographical range of a species. Thus, the aim of this study was to estimate global abundance of the Neotropical primate Brachyteles hypoxanthus (northern muriqui) and compare the results with available field estimates. Location From southern Bahia to Minas Gerais and Espírito Santo states, in the Brazilian Atlantic rain forest. Methods We compiled 25 recent occurrence localities of B. hypoxanthus and plotted them in grid cells of five different sizes (1, 25, 50, 75 and 100 km per side) to evaluate the performance and accuracy of abundance estimates over a wide range of scales. The abundance estimates were obtained by the negative binomial distribution (NBD) method and corrected by average group size to take into account primate social habits. To assess the accuracy of the method, the predicted abundances were then compared to recent independent field estimates. Results The NBD estimates were quite accurate in predicting B. hypoxanthus global abundance, once the gregarious habits of this species are taken into account. The predicted abundance estimates were not statistically different from those obtained from field estimates. Main conclusions The NBD method seems to be a quick and reliable approach to estimate species abundance once several limiting factors are taken into account, and can greatly impact conservation planning, but further applications in macroecological and ecological theory testing needs improvement of the method.     

Insights into plant biodiversity conservation in large river valleys in China: A spatial analysis of species and phylogenetic diversity

Large river valleys (LRVs) are heterogeneous in habitat and rich in biodiversity, but they are largely overlooked in policies that prioritize conservation. Here, we aimed to identify plant diversity hotspots along LRVs based on species richness and spatial phylogenetics, evaluate current conservation effectiveness, determine gaps in the conservation networks, and offer suggestions for prioritizing conservation. We divided the study region into 50 km × 50 km grid cells and determined the distribution patterns of seed plants by studying 124,927 occurrence points belonging to 14,481 species, using different algorithms. We generated phylogenies for the plants using the “V. PhyloMaker” R package, determined spatial phylogenetics, and conducted correlation analyses between different distribution patterns and spatial phylogenetics. We evaluated the effectiveness of current conservation practices and discovered gaps of hotspots within the conservation networks. In the process, we identified 36 grid cells as hotspots (covering 10% of the total area) that contained 83.4% of the species. Fifty‐eight percent of the hotspot area falls under the protection of national nature reserves (NNRs) and 83% falls under national and provincial nature reserves (NRs), with 42% of the area identified as conservation gaps of NNRs and 17% of the area as gaps of NRs. The hotspots contained high proportions of endemic and threatened species, as did conservation gaps. Therefore, it is necessary to optimize the layout of current conservation networks, establish micro‐nature reserves, conduct targeted conservation priority planning focused on specific plant groups, and promote conservation awareness. Our results show that the conservation of three hotspots in Southwest China, in particular, is likely to positively affect the protection of biodiversity in the LRVs, especially with the participation of the neighboring countries, India, Myanmar, and Laos.     

Habitat selection of black-and-white snub-nosed monkeys (Rhinopithecus bieti) in Tibet: implications for species conservation

As anthropogenic habitat changes are often considered a threat to natural ecosystems and wildlife, a sound understanding of the effects of habitat alteration on endangered species is crucial when designing management strategies or performing conservation activities. Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are categorized as endangered on the IUCN Red List and are endemic to the trans-Himalayas in China. At present, there are only 15 groups and 2,500 individuals remaining in the wild, and they are facing intense habitat degradation with selective logging for house building and firewood. Habitat deterioration through wood extraction is occurring at Xiaochangdu, Tibet, where one stable group of R. bieti lives in a marginal habitat in the northernmost part of the species' distribution. To understand the species' response to selective logging in an extremely marginal habitat, data on habitat preference and diet composition of a group of R. bieti were collected at Xiaochangdu from 2003 to 2005. The monkeys used different habitats nonrandomly during the year. The selection index for secondary conifer forest (SC), where selective logging has occurred, was the highest of all habitat types (>1), suggesting that the groups strongly preferred SC. The monkeys fed more on buds/leaves, more on flowers/fruit/seeds, and less on lichen in SC than in primary conifer forest (PC). Dietary diversity was significantly higher in SC than in PC. These results indicate that over the short term, low-intensity disturbances may result in increased foliage diversity that enable groups of R. bieti to survive in this marginal habitat.     

Physiological tolerances of juvenile robust redhorse, Moxostoma robustum: conservation implications for an imperiled species

The robust redhorse, Moxostoma robustum (Teleostei: Catostomidae), is an imperiled sucker native to large rivers of the Atlantic slope of the southeastern United States. Juvenile M. robustum were tested for tolerances to temperature, salinity, pH, and hypoxia in order to evaluate basic early life-history requirements. Static (acute) tests resulted in estimates of mean lower temperature tolerances (5.3–19.4 °C) that varied with prior thermal acclimation and indicated no apparent difference in tolerance among fish 30, 60, and 90 days old. Fish acclimated to 20 °C and 30 °C had significantly different mean critical thermal maxima (34.9 °C and 37.2 °C, respectively) and exhibited pronounced increased opercular ventilation rates with elevated temperatures. Fish exposed to acute and chronic increases in salinity showed unusual patterns of mortality above the isosmotic point (9 ppt) that reflected possible differences in body mass and prior acclimation conditions (i.e., water ionic composition); small fish and those held in soft water were the least tolerant of increased salinity. Abrupt exposure to extreme pH values resulted in greater than 50% mortality at pH values below 4.3 and above 9.5 within a 96-hour period. Fish exposed to progressive hypoxia utilized aquatic surface respiration at a mean oxygen concentration of 0.72–0.80 mg O₂ l^-1 (20 °C and 30 °C acclimated fish, respectively), and lost equilibrium at 0.54–0.57 mg O₂ l^-1. Juvenile M. robustum are moderately tolerant of a wide range of ambient physicochemical parameters, but further research is needed to determine how both abiotic and biotic factors have contributed to population decline and extirpation of this species.     

Species vulnerability to climate change: impacts on spatial conservation priorities and species representation

Climate change may shrink and/or shift plant species ranges thereby increasing their vulnerability and requiring targeted conservation to facilitate adaptation. We quantified the vulnerability to climate change of plant species based on exposure, sensitivity and adaptive capacity and assessed the effects of including these components in complementarity‐based spatial conservation prioritisation. We modelled the vulnerability of 584 native plant species under three climate change scenarios in an 11.9 million hectare fragmented agricultural region in southern Australia. We represented exposure as species' geographical range under each climate change scenario as quantified using species distribution models. We calculated sensitivity as a function of the impact of climate change on species' geographical ranges. Using a dispersal kernel, we quantified adaptive capacity as species' ability to migrate to new geographical ranges under each climate change scenario. Using Zonation, we assessed the impact of individual components of vulnerability (exposure, sensitivity and adaptive capacity) on spatial conservation priorities and levels of species representation in priority areas under each climate change scenario. The full vulnerability framework proved an effective basis for identifying spatial conservation priorities under climate change. Including different dimensions of vulnerability had significant implications for spatial conservation priorities. Incorporating adaptive capacity increased the level of representation of most species. However, prioritising sensitive species reduced the representation of other species. We conclude that whilst taking an integrated approach to mitigating species vulnerability to climate change can ensure sensitive species are well‐represented in a conservation network, this can come at the cost of reduced representation of other species. Conservation planning decisions aimed at reducing species vulnerability to climate change need to be made in full cognisance of the sensitivity of spatial conservation priorities to individual components of vulnerability, and the trade‐offs associated with focussing on sensitive species.     

Area, shape and isolation of tropical forest fragments: effects on tree species diversity and implications for conservation

Aim To quantify the influences of forest area, shape and isolation on tree species diversity in Ghana and to compare their significance with the influences of climate (average annual rainfall) and disturbance (fire burn, logging, agriculture). Location The forest zone of southern Ghana, West Africa (between 5 and 8° N). Methods For twenty‐two forest fragments (1) bivariate regression analyses of tree species diversity (number and composition) were employed with forest spatial geometry, climate and disturbance variables. (2) Multivariate regression analyses of tree species number and all seven environmental variables were used to determine the variability in tree species number that could be accounted for by these environmental variables. Results Forest area, shape and isolation accounted for sharply decreasing proportions of variability in tree species diversity. Large forest fragments contained the greatest numbers of tree species and the highest proportions of rare tree species; irregular fragments had high proportions of regenerating, light‐demanding pioneers and mature, animal‐dispersed species and isolated fragments were floristically similar to less isolated fragments. Fire burn and average annual rainfall accounted for small, but nevertheless significant, proportions of variability in tree species diversity. Logging and agriculture were non‐significant variables. Main conclusions (1) Forest area is the most important consideration when planning tropical forest reserves. (2) Management of disturbance should take priority over management of forest shape if higher levels of tree diversity and species quality are to be maintained. (3) If new reserves are to be designated, they should be located within different climatic zones in order to capture a large fraction of the regional biota. (4) Biogeographers have an important role to play in formulating and testing hypotheses at a broad spatial scale and ultimately, informing conservation management within the tropical biome.     

On the verge of extinction: genetics of the critically endangered Iberian plant species, Borderea chouardii (Dioscoreaceae) and implications for conservation management

Borderea chouardii is a relictual and dioecious, strictly sexually reproducing, long-living geophyte of the Dioscoreaceae family. Previous biological and demographic studies have indicated the existence of a uniformly distributed panmictic population of this taxon at the southernmost Spanish pre-Pyrenean mountain ranges where it occurs in rather inaccessible crevices of a single limestone cliff. However, individuals of B. chouardii are spatially subdivided into two subpopulations located, respectively, on the upper and lower parts of the cliff, and vertically separated 150 m. Because of its extreme rarity, B. chouardii was the first Iberian taxon to have a specific conservation plan and has been included in several red lists under the category of critically endangered (CR). However, no previous attempts have been conducted to analyse the fine scale evolutionary mechanisms involved in its present microspatial distribution. Genetic diversity and population structure have been investigated through the analysis of neutral hypervariable markers such as simple sequence repeats (SSRs) and randomly amplified polymorphic DNAs (RAPDs) to unravel the impact of life history traits in the differentiation of the two subpopulations. Both types of molecular markers were unequivocal in distinguishing two genetically distinct groups of individuals corresponding to their spatial separation. However, SSRs detected a higher level of subpopulation differentiation (F(ST) = 0.35, R(ST) = 0.32) than RAPDs (F(ST) = 0.21). SSR data indicated significant deviation from random dispersal of genes and genotypes between the two groups, suggesting that mating occurs mainly among individuals within subpopulations, thus, favouring the divergence between the two groups. This microevolutionary differentiation scenario might have been caused by a coupled effect of past genetic drift and reproductive isolation, as a result of strong glacial age bottlenecks and inefficient dispersal system of pollen and seeds, respectively. The identification of such genetic structure in this narrow endemic prompts a modification of the management strategies of its single extant population.