Improving the viability of large-mammal populations by using habitat and landscape models to focus conservation planning

2010 ◽  
Vol 37 (5) ◽  
pp. 401 ◽  
Author(s):  
Yongyut Trisurat ◽  
Anak Pattanavibool ◽  
George A. Gale ◽  
David H. Reed

Context. Assessing the viability of animal populations in the wild is difficult or impossible, primarily because of limited data. However, there is an urgent need to develop methods for estimating population sizes and improving the viability of target species. Aims. To define suitable habitat for sambar (Cervus unicolor), banteng (Bos javanicus), gaur (Bos gaurus), Asian elephant (Elephas maximus) and tiger (Panthera tigris) in the Western Forest Complex, Thailand, and to assess their current status as well as estimate how the landscape needs to be managed to maintain viable populations. Methods. The present paper demonstrates a method for combining a rapid ecological assessment, landscape indices, GIS-based wildlife-habitat models, and knowledge of minimum viable population sizes to guide landscape-management decisions and improve conservation outcomes through habitat restoration. Key results. The current viabilities for gaur and elephant are fair, whereas they are poor for tiger and banteng. However, landscape quality outside the current distributions was relatively intact for all species, ranging from moderate to high levels of connectivity. In addition, the population viability for sambar is very good under the current and desired conditions. Conclusions. If managers in this complex wish to upgrade the viabilities of gaur, elephant, tiger and banteng within the next 10 years, park rangers and stakeholders should aim to increase the amount of usable habitat by ~2170 km2 or 17% of existing suitable habitats. The key strategies are to reduce human pressures, enhance ungulate habitats and increase connectivity of suitable habitats outside the current distributions. Implications. The present paper provides a particularly useful method for managers and forest-policy planners for assessing and managing habitat suitability for target wildlife and their population viability in protected-area networks where knowledge of the demographic attributes (e.g. birth and death rates) of wildlife populations are too limited to perform population viability analysis.


2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Pavan Kumar ◽  
Manmohan Dobriyal ◽  
A. K. Pandey ◽  
Meenu Rani

Wild tigers experience unparalleled coercion due to habitat destruction, prey reduction and commercial poaching. The Indian tiger (Panthera tigris tigris) one of the world's most endangered carnivore species, and is now thought to be in the verge of extinction in the wild. Sariska National Park in India is considered to be a highly suitable habitat for the tigers. Relocation and change in habitat of these living giant creatures is a thought of study for their survival and existence in the coming future considering change in climatic conditions. But the main problem for the tigers in the new habitat will be poaching and the human-wildlife conflicts. Integrated geospatial techniques provide accurate, cost-effective as well as time-effective method for habitat evaluation. The aim of the study is current status followed by opportunities and challenges. The results point out a large and comprehensive research on each of these issues, in particular on the community involvement in wildlife management and government policies.



Author(s):  
Matthew C. Fitzpatrick ◽  
Aaron M. Ellison

Climatic change likely will exacerbate current threats to carnivorous plants. However, estimating the severity of climatic change is challenged by the unique ecology of carnivorous plants, including habitat specialization, dispersal limitation, small ranges, and small population sizes. We discuss and apply methods for modeling species distributions to overcome these challenges and quantify the vulnerability of carnivorous plants to rapid climatic change. Results suggest that climatic change will reduce habitat suitability for most carnivorous plants. Models also project increases in habitat suitability for many species, but the extent to which these increases may offset habitat losses will depend on whether individuals can disperse to and establish in newly suitable habitats outside of their current distribution. Reducing existing stressors and protecting habitats where numerous carnivorous plant species occur may ameliorate impacts of climatic change on this unique group of plants.



Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 84
Author(s):  
Huanchu Liu ◽  
Hans Jacquemyn ◽  
Xingyuan He ◽  
Wei Chen ◽  
Yanqing Huang ◽  
...  

Human pressure on the environment and climate change are two important factors contributing to species decline and overall loss of biodiversity. Orchids may be particularly vulnerable to human-induced losses of habitat and the pervasive impact of global climate change. In this study, we simulated the extent of the suitable habitat of three species of the terrestrial orchid genus Cypripedium in northeast China and assessed the impact of human pressure and climate change on the future distribution of these species. Cypripedium represents a genus of long-lived terrestrial orchids that contains several species with great ornamental value. Severe habitat destruction and overcollection have led to major population declines in recent decades. Our results showed that at present the most suitable habitats of the three species can be found in Da Xing’an Ling, Xiao Xing’an Ling and in the Changbai Mountains. Human activity was predicted to have the largest impact on species distributions in the Changbai Mountains. In addition, climate change was predicted to lead to a shift in distribution towards higher elevations and to an increased fragmentation of suitable habitats of the three investigated Cypripedium species in the study area. These results will be valuable for decision makers to identify areas that are likely to maintain viable Cypripedium populations in the future and to develop conservation strategies to protect the remaining populations of these enigmatic orchid species.



Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1604
Author(s):  
Sun Hee Hong ◽  
Yong Ho Lee ◽  
Gaeun Lee ◽  
Do-Hun Lee ◽  
Pradeep Adhikari

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km2, and 990.29 km2, respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (<36° latitude), the central and northern regions are also predicted to have substantial increases in suitable habitat areas. Our study revealed that climate change would exacerbate the threat of northward weed invasions by shifting the climatic barriers of invasive weeds from the southern region. Thus, it is essential to initiate control and management strategies in the southern region to prevent further invasions into new areas.



Oryx ◽  
2021 ◽  
pp. 1-10
Author(s):  
Desiree Andersen ◽  
Yoonjung Yi ◽  
Amaël Borzée ◽  
Kyungmin Kim ◽  
Kwang-Seon Moon ◽  
...  

Abstract Reintroductions 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.



2011 ◽  
Vol 278 (1719) ◽  
pp. 2728-2736 ◽  
Author(s):  
Gwenaël Quaintenne ◽  
Jan A. van Gils ◽  
Pierrick Bocher ◽  
Anne Dekinga ◽  
Theunis Piersma

Local studies have shown that the distribution of red knots Calidris canutus across intertidal mudflats is consistent with the predictions of an ideal distribution, but not a free distribution. Here, we scale up the study of feeding distributions to their entire wintering area in western Europe. Densities of red knots were compared among seven wintering sites in The Netherlands, UK and France, where the available mollusc food stocks were also measured and from where diets were known. We tested between three different distribution models that respectively assumed (i) a uniform distribution of red knots over all areas, (ii) a uniform distribution across all suitable habitat (based on threshold densities of harvestable mollusc prey), and (iii) an ideal and free distribution (IFD) across all suitable habitats. Red knots were not homogeneously distributed across the different European wintering areas, also not when considering suitable habitats only. Their distribution was best explained by the IFD model, suggesting that the birds are exposed to interference and have good knowledge about their resource landscape at the spatial scale of NW Europe, and that the costs of movement between estuaries, at least when averaged over a whole winter, are negligible.



Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 577
Author(s):  
Héctor Zumbado-Ulate ◽  
Catherine L. Searle ◽  
Gerardo Chaves ◽  
Víctor Acosta-Chaves ◽  
Alex Shepack ◽  
...  

Treefrogs represent 22% of amphibian species in Costa Rica, but gaps in the knowledge about this group of amphibians can impede conservation efforts. In this study, we first updated the status of Costa Rican treefrogs and found that a total of 38% of treefrog species are threatened according to the most recent IUCN assessment in 2019. Additionally, 21% of Costa Rican treefrog species have a high vulnerability to extinction according to environmental vulnerability scores. Then, we predicted the historical climatic suitability of eight target species that we expected to have exhibited changes in their ranges in the last 20 years. We assessed the location of new occurrence records since 2000 to identify recovery, range expansion, or previously underestimated ranges due to methodological limitations. We also estimated the area of each species’ suitable habitat with two metrics: extent of suitable habitat (ESH) and area of minimum convex polygon (AMCP). Six declined species exhibited recovery (i.e., new occurrences across historical range after 2000), with the widest recovery found in Agalychnis annae. We also found that Isthmohyla pseudopuma appears to have spread after the decline of sympatric species and that the range of I. sukia was originally underestimated due to inadequate detection. We found that the ESH was 32–49% smaller than the AMCP for species that are slowly recovering; however, the ESH is similar or greater than the AMCP for species that are recovering in most of their ranges, as well as rare species with widespread ranges. Results of this work can be used to evaluate the risk of environmental threats and prioritize regions for conservation purposes.



PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11972
Author(s):  
Samuel Georgian ◽  
Lance Morgan ◽  
Daniel Wagner

The Salas y Gómez and Nazca ridges are two adjacent seamount chains off the west coast of South America that collectively contain more than 110 seamounts. The ridges support an exceptionally rich diversity of benthic and pelagic communities, with the highest level of endemism found in any marine environment. Despite some historical fishing in the region, the seamounts are relatively pristine and represent an excellent conservation opportunity to protect a global biodiversity hotspot before it is degraded. One obstacle to effective spatial management of the ridges is the scarcity of direct observations in deeper waters throughout the region and an accompanying understanding of the distribution of key taxa. Species distribution models are increasingly used tools to quantify the distributions of species in data-poor environments. Here, we focused on modeling the distribution of demosponges, glass sponges, and stony corals, three foundation taxa that support large assemblages of associated fauna through the creation of complex habitat structures. Models were constructed at a 1 km2 resolution using presence and pseudoabsence data, dissolved oxygen, nitrate, phosphate, silicate, aragonite saturation state, and several measures of seafloor topography. Highly suitable habitat for each taxa was predicted to occur throughout the Salas y Gómez and Nazca ridges, with the most suitable habitat occurring in small patches on large terrain features such as seamounts, guyots, ridges, and escarpments. Determining the spatial distribution of these three taxa is a critical first step towards supporting the improved spatial management of the region. While the total area of highly suitable habitat was small, our results showed that nearly all of the seamounts in this region provide suitable habitats for deep-water corals and sponges and should therefore be protected from exploitation using the best available conservation measures.



2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiming Liu ◽  
Lianchun Wang ◽  
Caowen Sun ◽  
Benye Xi ◽  
Doudou Li ◽  
...  

AbstractSapindus (Sapindus L.) is a widely distributed economically important tree genus that provides biodiesel, biomedical and biochemical products. However, with climate change, deforestation, and economic development, the diversity of Sapindus germplasms may face the risk of destruction. Therefore, utilising historical environmental data and future climate projections from the BCC-CSM2-MR global climate database, we simulated the current and future global distributions of suitable habitats for Sapindus using a Maximum Entropy (MaxEnt) model. The estimated ecological thresholds for critical environmental factors were: a minimum temperature of 0–20 °C in the coldest month, soil moisture levels of 40–140 mm, a mean temperature of 2–25 °C in the driest quarter, a mean temperature of 19–28 °C in the wettest quarter, and a soil pH of 5.6–7.6. The total suitable habitat area was 6059.97 × 104 km2, which was unevenly distributed across six continents. As greenhouse gas emissions increased over time, the area of suitable habitats contracted in lower latitudes and expanded in higher latitudes. Consequently, surveys and conservation should be prioritised in southern hemisphere areas which are in danger of becoming unsuitable. In contrast, other areas in northern and central America, China, and India can be used for conservation and large-scale cultivation in the future.



2021 ◽  
Vol 8 ◽  
Author(s):  
Mary C. Fabrizio ◽  
Troy D. Tuckey ◽  
Aaron J. Bever ◽  
Michael L. MacWilliams

The sustained production of sufficient forage is critical to advancing ecosystem-based management, yet factors that affect local abundances and habitat conditions necessary to support aggregate forage production remain largely unexplored. We quantified suitable habitat in the Chesapeake Bay and its tidal tributaries for four key forage fishes: juvenile spotted hake Urophycis regia, juvenile spot Leiostomus xanthurus, juvenile weakfish Cynoscion regalis, and bay anchovy Anchoa mitchilli. We used information from monthly fisheries surveys from 2000 to 2016 coupled with hindcasts from a spatially interpolated model of dissolved oxygen and a 3-D hydrodynamic model of the Chesapeake Bay to identify influential covariates and construct habitat suitability models for each species. Suitable habitat conditions resulted from a complex interplay between water quality and geophysical properties of the environment and varied among species. Habitat suitability indices ranging between 0 (poor) and 1 (superior) were used to estimate seasonal and annual extents of suitable habitats. Seasonal variations in suitable habitat extents in Chesapeake Bay, which were more pronounced than annual variations during 2000–2016, reflected the phenology of estuarine use by these species. Areas near shorelines served as suitable habitats in spring for juvenile spot and in summer for juvenile weakfish, indicating the importance of these shallow areas for production. Tributaries were more suitable for bay anchovy in spring than during other seasons. The relative baywide abundances of juvenile spot and bay anchovy were significantly related to the extent of suitable habitats in summer and winter, respectively, indicating that Chesapeake Bay habitats may be limiting for these species. In contrast, the relative baywide abundances of juvenile weakfish and juvenile spotted hake varied independently of the spatial extent of suitable habitats. In an ecosystem-based approach, areas that persistently provide suitable conditions for forage species such as shoreline and tributary habitats may be targeted for protection or restoration, thereby promoting sufficient production of forage for predators. Further, quantitative habitat targets or spatial thresholds may be developed for habitat-limited species using estimates of the minimum habitat area required to produce a desired abundance or biomass; such targets or thresholds may serve as spatial reference points for management.



Sign in / Sign up

Export Citation Format

Share Document