Prioritizing Species by Conservation Value and Vulnerability: A New Index Applied to Species Threatened by Sea-Level Rise and Other Risks in Florida

Land-use change, climate change, and sea-level rise (SLR) pose substantial threats to biodiversity. Conservation resources are limited and must be directed toward the species and ecosystems that are most vulnerable, biologically distinct, likely to respond favorably to conservation interventions, and valuable ecologically, socially, or economically. Many prioritization and vulnerability assessment schemes exist, each emphasizing different types of vulnerabilities and values and often yielding disparate evaluations of the same species. We developed an integrative and flexible framework that incorporates existing assessments and is useful for illuminating the differences between systems such as the IUCN Red List, the US Endangered Species Act, and NatureServe\u27s Conservation Status Assessment and Climate Change Vulnerability Index. The Standardized Index of Vulnerability and Value Assessment (SIVVA) includes five advancements over existing tools: (1) the ability to import criteria and data from previous assessments, (2) explicit attention to SLR, (3) a flexible system of scoring, (4) metrics for both vulnerability and conservation value, and (5) quantitative and transparent accounting of multiple sources of uncertainty. We apply this system to 40 species in Florida previously identified as being vulnerable to SLR by the year 2100, describe the influence of different types of uncertainty on the resulting prioritizations, and explore the power of SIVVA to evaluate alternative prioritization schemes. This type of assessment is particularly relevant in low-lying coastal regions where vulnerability to SLR is predictable, severe, and likely to interact synergistically with other threats such as coastal development

The consequences of disrupted dispersal in fragmented red-cockaded woodpecker Picoides borealis populations.

1. Habitat fragmentation may adversely affect animal populations through several mechanisms. However, little is known about how the impacts of some of these mechanisms are manifested in altered dynamics of wild populations. 2. We used a spatially explicit individual-based simulation model to examine the potential effects of disrupted dispersal due to fragmentation on the population dynamics of the endangered, co-operatively breeding, red-cockaded woodpecker Picoides borealis. 3. We simulated population dynamics as a function of population size and spatial aggregation of territories. Dispersal success (but not mortality or fecundity) was an emergent property of model runs. In the model all female and some male fledglings dispersed in straight lines in random directions, and the remaining males stayed on their natal territories as helpers and competed for breeding vacancies in their immediate neighbourhood. 4. Population trend was tied to the higher dispersal success of both males and females in larger and less fragmented populations. Helpers were more successful than dispersing males. Male breeder recruitment depended entirely on helpers when populations were small (25 or 100 territories). 5. Declining populations were characterized by high emigration rates and both failure and delay in female recruitment. The large numbers of unpaired males resulted in lowered reproductive output at the population level and in the loss of territories. Populations of 25 territories were stable when territories were highly aggregated, despite high emigration rates. These results closely match empirical observations. 6. A number of co-operatively breeding species are endangered. The unusual dispersal behaviour of helpers may make such species sensitive to habitat fragmentation but also resilient to reductions in population size when territories are aggregated. Small populations of co-operative breeders may have considerable conservation value as a source of genetic diversity