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Using GIS to Monitor Forest Fragmentation and Designate Wood Thrush Habitat for Conservation Along the Eastern United States

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Using GIS to Monitor Forest Fragmentation and Designate Wood Thrush Habitat for Conservation Along the Eastern United States Using GIS to Monitor Forest Fragmentation and Designate Wood Thrush Habitat for Conservation along the eastern United States By Isabel Esparza Background and Hypothesis The Wood Thrush (Hylocichla mustelina) is a neotropical migratory songbird whose renowned flute-like song can be commonly heard in eastern U.S. forests in the spring through early summer. This beautiful and reclusive bird can be observed thrashing and hopping around the leaf litter on the forest floor, probing for insects to eat. Though this native species is still abundant in the U.S., its numbers are rapidly declining. Reasons for Wood Thrush decline are currently being researched, but hypotheses include increased numbers of brown-headed cowbird (Molothrus ater) nest parasitism, which lowers Wood Thrush nestling survival. Also, the Wood Thrush relies on interior deciduous forest for nesting, and increased habitat fragmentation is diminishing suitable Wood Thrush habitat in the United States (“Wood Thrush” 2013). Habitat fragmentation is the process of breaking down continuous habitat into smaller, isolated patches, thus reducing the overall amount of habitat and producing smaller isolated patches of habitat with decreased interior and increased edge. Increase in edge habitat facilitates the proliferation of invasive species of plants and animals as well as predators. Furthermore, the creation of new edge habitat allows species such as the brown-headed cowbird to infiltrate into habitats which were once interior forest. Wood Thrush thrive in interior forest habitat, and experience decreased success in edge habitats because edge habitats make Wood Thrush nests more vulnerable to predation by raccoons, domestic or feral cats, crows, jays, and the brood parasite brown-headed cowbird. In this project I propose that GIS software could be used to monitor and measure forest fragmentation throughout the Wood Thrush’s entire migratory range along the eastern U.S. and also wintering habitat of lowland tropical forests in Central America. I hypothesize that the use of GIS software is critical for measuring forest fragmentation along the Wood Thrush’s habitat and also for identifying habitat patches which are large enough to support Wood Thrush nests and should be conserved. Literature Review Small forest fragments are usually population sinks for Wood Thrush. Results of a classic study published by Weinberg and Roth in 1998 in the University of Delaware woods proved that Wood Thrush biodiversity and productivity decreases with decreasing habitat area. Less than 51% of Wood Thrush females fledged more than 2 nestlings in a two year period in smaller habitats (<2.1 ha). In the larger habitats, a 15 ha site, Wood Thursh were more successful and fledged more young. Also in the larger habitat patches, there were lower rates of predation than in the smaller forest fragments. Also in both years of the study, the percent of nests lost and the percent of nests parasitized by cowbirds were higher in the smaller patches than in the larger patches studied (Weinberg and Roth 1998). Though the Cornell Lab of Ornithology currently states that the Wood Thrush is of Least Concern for conservation, the Cornell experts do state that Wood Thrush populations are declining significantly. Population surveys from 1966 to 2009 show that Wood Thrush numbers in the U.S. are declining at a rate of 2% per year. Thus, the overall U.S Wood Thrush population has decreased by 50% in this time period. The stark decline calls for immediate and novel conservation actions in order to protect the Wood Thrush from demise in a time when human development is seriously hurting wildlife. Data Requirements GIS software could be used to monitor Wood Thrush forest habitat. Landsat images and data layers could produce NDVI maps which depict the amount of vegetative biomass along the Wood Thrush’s migratory habitat range. I propose that GIS software should be used to assess the historical range of Wood Thrush habitat, and see how it is changing over time to the present. A map of the eastern U.S. Wood Thrush range could be produced for intervals of every five years, or a thematic map could be made which shows the forest fragmentation. Also, once these maps are produced, GIS analysts could produce maps of ideal Wood Thrush habitat based off of a patches’ size. Bigger patches have more interior habitat which the Wood Thrush needs, thus, a Raster Calculator could be used to identify patches with an area greater than 20 hectares (minimum ideal habitat size suggested here, based off of to Weinberg and Roth 1998). If the GIS maps reveal where forests are being fragmented the most in the Wood Thrush migratory habitat, then research and nest-monitoring efforts could be concentrated in bigger forest patches so as to see where to allocate conservation efforts and funding. Anticipated Results I anticipate that GIS maps will show increasing forest fragmentation all along the Wood Thrush’s migratory range. I also believe that the maps will reveal some forest fragments which may be greater than 20 ha. These large forest fragments should be surveyed by wildlife biologists and a team of volunteers to see if these fragments would make suitable Wood Thrush habitat. If so, conservation efforts and funds should be allocated to protecting patches that make suitable Wood Thrush habitat. Policy Application Policy application depends on what agency or party acts to protect Wood Thrush habitat. Protected habitat should be monitored by the local authorities or department of agriculture in the specific state. Also, outreach programs by local universities should strive to educate the public about the dangers of habitat fragmentation and how it greatly decreases biodiversity, which is the fuel that runs our planet. Budget Item Quantity Cost Arc GIS Software 1 $1500 GIS Software Analyst Work for 5 Years $50,000 * 5 = $250,000 Indirect Costs from N/A $200,000 Institutional Oversight, Cooperation, Resources Total Cost: $451,500 Timeframe Phase Begin End 5 Year Forest Fragmentation January 2014 January 2019 Monitoring Compile Data and Create GIS January 2019 April 2019 Maps Conduct Land Surveys of May 2019 August 2019 Habitat Indicated by GIS maps, search for nests Works Cited Weinberg, H.J. 1998. Forest Area and Habitat Quality for Nesting Woodthrushes. Auk 115: 879- 889. “Wood Thrush”. The Cornell Lab of Ornithology. Cornell University. 2013. 5 December 2013. Web. .
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