Challenges in updating habitat suitability models: An example with the lesser prairie-chicken

Habitat loss from land-use change is one of the top causes of declines in wildlife species of concern. As such, it is critical to assess and reassess habitat suitability as land cover and anthropogenic features change for both monitoring and developing current information to inform management decisions. However, there are obstacles that must be overcome to develop consistent assessments through time. A range-wide lek habitat suitability model for the lesser prairie-chicken (Tympanuchus pallidicinctus), currently under review by the U. S. Fish and Wildlife Service for potential listing under the Endangered Species Act, was published in 2016. This model was based on lek data from 2002 to 2012, land cover data ranging from 2001 to 2013, and anthropogenic features from circa 2011, and has been used to help guide lesser prairie-chicken management and anthropogenic development actions. We created a second iteration model based on new lek surveys (2015 to 2019) and updated predictors (2016 land cover and cleaned/updated anthropogenic data) to evaluate changes in lek suitability and to quantify current range-wide habitat suitability. Only three of 11 predictor variables were directly comparable between the iterations, making it difficult to directly assess what predicted changes resulted from changes in model inputs versus actual landscape change. The second iteration model showed a similar positive relationship with land cover and negative relationship with anthropogenic features to the first iteration, but exhibited more variation among candidate models. Range-wide, more suitable habitat was predicted in the second iteration. The Shinnery Oak Ecoregion, however, exhibited a loss in predicted suitable habitat that could be due to predictor source changes. Iterated models such as this are important to ensure current information is being used in conservation and development decisions.

Conservation of threatened San Joaquin antelope squirrels: distribution surveys, habitat suitability, and conservation recommendations

The San Joaquin antelope squirrel (Ammospermophilus nelsoni: SJAS) is listed as Threatened pursuant to the California Endangered Species Act due to profound habitat loss throughout its range in the San Joaquin Desert in California. Habitat loss is still occurring and critical needs for SJAS include identifying occupied sites, quantifying optimal habitat conditions, and conserving habitat. Our objectives were to (1) conduct surveys to identify sites where SJAS were present, (2) assess habitat attributes on all survey sites, (3) generate a GIS-based model of SJAS habitat suitability, (4) use the model to determine the quantity and quality of remaining habitat, and (5) use these results to develop conservation recommendations. SJAS were detected on 160 of the 326 sites we surveyed using automated camera stations. Sites with SJAS typically were in arid upland shrub scrub communities where desert saltbush (Atriplex polycarpa) or jointfir (Ephedra californica) were the dominant shrubs, although shrubs need not be present for SJAS to be present. Sites with SJAS usually had relatively sparse ground cover with >10% bare ground and Arabian grass (Schismus arabicus) was the dominant grass. SJAS were more likely to occur on sites where kangaroo rats (Dipodomys spp.) were present and burrow abundance was greater, but SJAS were less likely to be present on sites with California ground squirrels (Otospermophilus beecheyi). Based on our habitat suitability model, an estimated 5,931 km2 of high or moderately high quality habitat and 4,753 km2 of lower quality habitat remain. To conserve SJAS, we recommend (1) conducting additional SJAS surveys on sites not surveyed but with suitable habitat, (2) conserving unprotected lands with suitable habitat, (3) managing vegetation on occupied sites if necessary, (4) restoring disturbed lands to increase suitability for SJAS, and (5) conducting translocations of SJAS to unoccupied sites with suitable habitat.

Potential habitat connectivity for Malayan gaur (Bos gaurus) in a fragmented forest area in Peninsular Malaysia

Aim: To predict the distribution of suitable habitats for Malayan gaur (Bos gaurus) at a highly fragmented forest area in Peninsular Malaysia and to identify the potential connectivity between suitable habitat patches. Methodology: Maximum entropy (MaxEnt) approach was used to predict the distribution of suitable habitats of the Malayan gaur. Gaur presence-only data and six environmental variables were collated for the habitat suitability modeling, and area under curve (AUC) value was used to estimate the performance of the model. The resulting model was then used to derive a potential connectivity map through least-cost analysis using Corridor Designer toolbox in ArcGIS 10.4. Results: The AUC value of the habitat suitability model was 0.84. Distance from urban areas indicated the highest relative contribution to the model (26.9%), followed by distance from water body (24.2%) land use (18.0%) elevation (14.3%), slope (14.0%) and lithology (2.6%). Predicted suitable habitats for gaur were found mostly in lowland forest areas, especially in the vicinity of rivers within forest reserves. A total of five wildland blocks were derived from the habitat suitability model, and several potential corridor swaths were identified connecting the wildland blocks. Interpretation: The absence of gaur occurrence in suitable habitats suggest that fragmented habitats greatly affected gaur distribution and population. Road network and agricultural lands are the major barriers of gaur movement as they are very sensitive towards disturbances and conflict. Thus, this research proposes potential connectivity at a regional scale for Malayan gaur for use in future planning in conservation, management and development.

Pemodelan Spasial Kesesuaian Habitat Elang Jawa (Nisaetus bartelsi) di Taman Nasional Bromo Tengger Semeru (Spatial Modeling of Javan Hawk-Eagle (Nisaetus bartelsi) Habitat Suitability in Bromo Tengger Semeru National Park)

Bromo Tengger Semeru National Park (TNBTS) is a conservation area as the habitat of endemic species in Java Island, such as the Javan hawk-eagle (Nisaetus bartelsi). One of the spatial models of habitat is the Ecological Niche Modeling (ENM) approach. This study aimed to determine habitat suitability for the Javan hawk-eagle in TNBTS. The research was conducted from September 2019 to January 2020. The habitat suitability model used the present coordinate point data and the Javan hawk-eagle habitat environment variables. The data were then analyzed to build a Javan hawk-eagle habitat suitability model using the Maximum Entropy (MaxEnt) algorithm. The results showed three models of habitat suitability categories, i.e.: high of 15,131.18 ha (30%), medium 11,216.61 ha (22%), and low 23,298.41 ha (48%). The evaluation of the Javan hawk-eagle habitat suitability model in TNBTS has an excellent model accuracy with an AUC value of 0.97 and a standard deviation of 0.93.Keywords: endemic, habitat, Javan hawk-eagle, maximum entropy, spatial modeling