Providing insights on habitat connectivity for male brown bears: A combination of habitat suitability and landscape graph-based models

Abstract Background Understanding the impacts of past and contemporary climate change on biodiversity is critical for effective conservation. Amphibians have weak dispersal abilities, putting them at risk of habitat fragmentation and loss. Both climate change and anthropogenic disturbances exacerbate these risks, increasing the likelihood of additional amphibian extinctions in the near future. The giant spiny frog (Quasipaa spinosa), an endemic species to East Asia, has faced a dramatic population decline over the last few decades. Using the giant spiny frog as an indicator to explore how past and future climate changes affect landscape connectivity, we characterized the shifts in the suitable habitat and habitat connectivity of the frog. Results We found a clear northward shift and a reduction in the extent of suitable habitat during the Last Glacial Maximum for giant spiny frogs; since that time, there has been an expansion of the available habitat. Our modelling showed that “overwarm” climatic conditions would most likely cause a decrease in the available habitat and an increase in the magnitude of population fragmentation in the future. We found that the habitat connectivity of the studied frogs will decrease by 50–75% under future climate change. Our results strengthen the notion that the mountains in southern China and the Sino-Vietnamese transboundary regions can act as critical refugia and priority areas of conservation planning going forward. Conclusions Given that amphibians are highly sensitive to environmental changes, our findings highlight that the responses of habitat suitability and connectivity to climate change can be critical considerations in future conservation measures for species with weak dispersal abilities and should not be neglected, as they all too often are.

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Ants: A food source sought by Slovenian brown bears (Ursus arctos)?

Canadian Journal of Zoology ◽

10.1139/z03-151 ◽

2003 ◽

Vol 81 (12) ◽

pp. 1996-2005 ◽

Cited By ~ 23

Author(s):

C Große ◽

P Kaczensky ◽

F Knauer

Keyword(s):

Habitat Suitability ◽

Food Source ◽

Ursus Arctos ◽

Brown Bear ◽

Dry Mass ◽

Artificial Feeding ◽

Frequency Of Occurrence ◽

Brown Bears ◽

Ant Colonies ◽

Feeding Sites

In the heavily managed boreal forest of Scandinavia, ants, especially large colonies of red forest ants (Formica spp.), are abundant and brown bears (Ursus arctos) intensively feed on them. In contrast, the beech (Fagus sylvatica) forests of Slovenia provide only suboptimal habitat for ants and large ant colonies are virtually absent. To quantify how much ant use by brown bears is a matter of availability or preference, we quantified ant availability, species composition, and ant use. The estimated biomass of ants available to brown bears was very low in Slovenia compared with those in Sweden, averaging 135 vs. 9600 g/ha, respectively. Nevertheless, the frequency of occurrence of ants in Slovenian brown bear scats was high, averaging 85% and accounting for 25% of the ingested dry mass during the summer, which was nearly as much as their frequency of occurrence in Swedish brown bear scats during the summer. Although brown bears in Slovenia had year-round access to artificial feeding sites and the availability of ants is only about 1% of the biomass found in Sweden, they consumed about 50% of the quantity of ants compared with the brown bears in Sweden. Our results show that ants are an important and sought-after food source for brown bears in Slovenia, and the occurrence of ants should be considered in habitat-suitability models.

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Habitat connectivity and resource selection in an expanding bobcat (Lynx rufus) population

PeerJ ◽

10.7717/peerj.12460 ◽

2021 ◽

Vol 9 ◽

pp. e12460

Author(s):

Viorel D. Popescu ◽

Madeline Kenyon ◽

Ryan K. Brown ◽

Marissa A. Dyck ◽

Suzanne Prange ◽

...

Keyword(s):

Habitat Selection ◽

Home Range ◽

Habitat Suitability ◽

Resource Selection ◽

Population Level ◽

Habitat Connectivity ◽

Lynx Rufus ◽

Home Ranges ◽

Core Areas ◽

Selection For

Terrestrial carnivores are among the most imperiled species worldwide, yet some species are resilient and are recovering in human-dominated landscapes after decades or centuries of absence. Bobcat (Lynx rufus) populations were extirpated from much of Midwestern US in the mid-1800’s, and are currently expanding and recolonizing their former range. In this study, we investigated multi-scale habitat selection for Ohio’s expanding bobcat population, and examined habitat connectivity in order to evaluate the conduits for dispersal statewide. We used citizen observations collected between 1978 and 2019 and logistic regression to evaluate population-level habitat selection, and GPS telemetry data for 20 individuals collected between 2012 and 2014 and a distribution-weighted exponential Resource Selection Function to evaluate individual-level habitat selection within home ranges. At the population level, bobcats selected for higher amounts of forest and pasture (at a 50 km2 scale) and herbaceous vegetation (at 15–50 50 km2 scales), thus overall heterogeneous forested habitat. At individual (home range) level, bobcats selected for forested habitats with low road density and farther away from high traffic roads; they also showed weak selection for open habitat at the home range level. Male home ranges were significantly greater than female home ranges. Lastly, we used the population-level spatial outputs (i.e. habitat suitability map) to parameterize habitat connectivity models using circuit theory in the program Circuitscape. We tested three relationships between habitat suitability and resistance to movement and used a subset of data on potential dispersing individuals to evaluate which relationship performed best. All three relationships performed almost equally well, and we calculated a weighted averaged connectivity map as our final map. Habitat was highly permeable to movements between core areas of two genetically distinct subpopulations located in southeastern Ohio. We also identified potential dispersal corridors from the core areas to other regions of Ohio dominated by agriculture and suburban development via forested riparian corridors. Overall, our analysis offers new information on habitat selection and connectivity in a rebounding felid population and offers important ecological information for wildlife management strategies. We recommend that the suitability and connectivity models should be periodically updated until the population reaches an equilibrium, and be integrated with data from neighboring states for a comprehensive assessment of a conservation success story.

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Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

Marine Ecology Progress Series ◽

10.3354/meps13302 ◽

2020 ◽

Vol 641 ◽

pp. 159-175

Author(s):

J Runnebaum ◽

KR Tanaka ◽

L Guan ◽

J Cao ◽

L O’Brien ◽

...

Keyword(s):

Habitat Suitability ◽

Mixed Model ◽

Linear Mixed Model ◽

Gulf Of Maine ◽

Homarus Americanus ◽

Management Tool ◽

American Lobster ◽

Suitable Habitat ◽

Climate Conditions ◽

Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

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