Extinction risk from habitat fragmentation using metapopulation-based metrics

The world is becoming more developed as the human population steadily grows. With the increase in human influence, anthropomorphic habitat loss will only increase over time. Habitat fragmentation is the leading threat to species globally. Assessing fragmentation and determining sites of the most critical regions is vitally important for conservation efforts. One way of assessing fragmentation is by relating the spatial aspect to the biological aspect, via metapopulation dynamics. Specifically, metapopulation capacity allows for relative valuation of fragmented landscapes. However, a modification is required for it to operate at large-scale landscapes. The modified metric enables relative quantification value of fragmented habitat, with biological relevance for long-term extinction risk. Using the same spatially explicit components of metapopulation theory, we can also create a short-term measure of extinction risk, based on the instantaneous rate of expected decline post-fragmentation. This metric, extrapolated persistence time, along with the modified metapopulation capacity metric, can then be used in a variety of ways to determine high risk species and regions. Given that bird species are capable of an assortment of dispersal abilities, focusing within phylogenetic groups allows for more relevant comparisons between species. With the use of slopegraphs, we can instantly determine those species, within their families, with remaining ranges that have extremely low relative values for long or short term extinction risk. Of particular concern are those species considered to be at low risk of threat by the IUCN Red List, yet possess habitats that are critically fragmented. The metrics can be utilized in estimating overall landscape value, and estimating the contribution of specific patches to the overall landscape value; this would be useful in preservation and management decisions. Finally, by focusing on those cells that connect large patches, we can determine where restoration of habitat should be prioritized, for anything from the greatest increase in metapopulation capacity to the most number of species with ranges that could be reconnected.Ph. D.Includes bibliographical referencesIncludes vitaby Jessica K. Schnel