Vermont Project: Predicting Impacts of Future Human Population Growth and Development on Forest-dependent Wildlife Species

Vermont Project

Predicting Impacts of Future Human Population Growth and Development on Forest-dependent Wildlife Species

January 2009 - June 2012

Personnel

Participating Agencies

USFS McIntire-Stennis

Forest loss is perhaps the most important contemporary issue in the Northeast for wildlife species. Given increasing forest loss and fragmentation, the “problem” of how native fauna will respond to eminent land-use change is widespread, and requires tools and methods for understanding population responses as well as management recommendations for conservation. This study will integrate wildlife habitat modeling with GIS models of human population growth to quantify how various forest-dependent wildlife species will respond to projected increases in human population growth (year 2020) for the state of Vermont. The Vermont Cooperative Fish and Wildlife Researcher is collaborating with Dr. David Theobald (Colorado State University) on this work. The study will advance conservation planning by: 1) providing GIS layers on the contemporary distribution (probability of occurrence) for selected forest-dependent species; and 2) providing GIS layers that quantify risk for these same species given future human population growth and development.

Research Publications

Research Publications	Publication Date
Brown, M. L., T. M. Donovan, W. S. Schwenk, and D. M. Theobald. 2013. Predicting impacts of future human population growth and development on occupancy rates of forest-dependent birds . Biological Conservation. Available online 31 October 2013, ISSN 0006-3207, http://dx.doi.org/10.1016/j.biocon.2013.07.039 \| Abstract \| Download \| Publisher Website	October 2013	Forest loss and fragmentation are among the largest threats to forest-dwelling wildlife species today, and projected increases in human population growth are expected to increase these threats in the next century. We combined spatially-explicit growth models with wildlife distribution models to predict the effects of human development on 5 forest-dependent bird species in Vermont, New Hampshire, and Massachusetts, USA. We used single-species occupancy models to derive the probability of occupancy for each species across the study area in the years 2000 and 2050. Over half a million new housing units were predicted to be added to the landscape. The maximum change in housing density was nearly 30 houses per hectare; however, 30% of the towns in the study area were projected to add less than 1 housing unit per hectare. In the face of predicted human growth, the overall occupancy of each species decreased by as much as 38% (ranging from 19% to 38% declines in the worst-case scenario) in the year 2050. These declines were greater outside of protected areas than within protected lands. Ninety-seven percent of towns experienced some decline in species occupancy within their borders, highlighting the value of spatially-explicit models. The mean decrease in occupancy probability within towns ranged from 3% for hairy woodpecker to 8% for ovenbird and hermit thrush. Reductions in occupancy probability occurred on the perimeters of cities and towns where exurban development is predicted to increase in the study area. This spatial approach to wildlife planning provides data to evaluate trade-offs between development scenarios and forest-dependent wildlife species.
Brown, M. L., T. M. Donovan, R. M. Mickey, G. S. Warrington, W. S. Schwenk, and D. S. Theobald. 2017. Predicting effects of future development on a territorial forest songbird: methodology matters. Landscape Ecology 33:93-108. DOI 10.1007/s10980-017-0586-8 \| Abstract \| Download \| Publisher Website	October 2017	Context Projected increases in human population size are expected to increase forest loss and fragmentation in the next century at the expense of forest-dwelling species. Objectives We estimated landscape carrying capacity (Nk) for Ovenbirds in urban, suburban, exurban, and rural areas for the years 2000 and 2050, and compared changes in Nk with changes in occupancy probability. Methods Maximum clique analysis, a branch of mathematical graph theory, was used to estimate landscape carrying capacity, the maximum potential number of territories a given landscape is capable of supporting (Nk). We used occupancy probability maps as inputs for calculating Ovenbird Nk in the northeastern USA and a spatially explicit growth model to forecast future development patterns in 2050. We compared occupancy probability with estimates of Nk for urban, suburban, exurban, and rural areas for the years 2000 and 2050. Results In response to human population growth and development, Ovenbird Nk was predicted to decrease23% in urban landscapes, 28% in suburban landscapes, 43% in exurban landscapes, and 20% in rural landscapes. These decreases far exceeded decreases in mean occupancy probabilities that ranged between 2 and 5% across the same development categories. Thus, small decreases in occupancy probability between 2000 and 2050 translated to much larger decreases in Nk. Conclusions For the first time, our study compares occupancy probability with a species population metric, Nk, to assess the impact of future development. Maximum clique analysis is a tool that can be used to estimate Nk and inform landscape management and communication with stakeholders.

Cooperative Fish and Wildlife Research Units Program: Vermont Education, Research and Technical Assistance for Managing Our Natural Resources

Vermont Project

Predicting Impacts of Future Human Population Growth and Development on Forest-dependent Wildlife Species

January 2009 - June 2012

Personnel

Participating Agencies

Cooperative Fish and Wildlife Research Units Program: Vermont
Education, Research and Technical Assistance for Managing Our Natural Resources