Predictors of specialist avifaunal decline in coastal marshes

• Published in: Conservation biology 2017-02, Vol.31 (1), p.172-182
• Main Authors: Correll, Maureen D., Wiest, Whitney A., Hodgman, Thomas P., Shriver, W. Gregory, Elphick, Chris S., McGill, Brian J., O'Brien, Kathleen M., Olsen, Brian J.
• Format: Article
• Language: English
• Subjects: Accretion; agentes estresantes múltiples; Ammodramus; Ammodramus caudacutus; Ammodramus maritimus; Animals; anthropogenic activities; Anthropogenic changes; Anthropogenic factors; Avifauna; Birds; Coastal marshes; coasts; Communities; conservación; conservation; Conservation of Natural Resources; Degradation; Deposition; Ditches; Ditching; Ecosystem; Ecosystems; extinction; Extreme weather; Flooding; Floods; habitat destruction; Habitat loss; Humans; Marine; marismas; Marshes; Mitigation; multiple stressors; population trends; Rallus; resilience; roads; salt marshes; Saltmarsh Sparrow; Sea level; Sea level rise; Sediment; sediments; Soil erosion; Sparrows; Species extinction; Storms; tendencias poblacionales; tidal marsh; Tidal marshes; Trenching; Trends; Tringa; Water Movements; Wetlands
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/cobi.12797

Coastal marshes are one of the world's most productive ecosystems. Consequently, they have been heavily used by humans for centuries, resulting in ecosystem loss. Direct human modifications such as road crossings and ditches and climatic Stressors such as sea-level rise and extreme storm events have the potential to further degrade the quantity and quality of marsh along coastlines. We used an 18-year marsh-bird database to generate population trends for 5 avian species (Rallus crepitans, Tringa semipalmata semipalmata, Ammodramus nelsonii subvirgatus, Ammodramus caudacutus, and Ammodramus maritimus) that breed almost exclusively in tidal marshes, and are potentially vulnerable to marsh degradation and loss as a result of anthropogenic change. We generated community and species trends across 3 spatial scales and explored possible drivers of the changes we observed, including marsh ditching, tidal restriction through road crossings, local rates of sea-level rise, and potential for extreme flooding events. The specialist community showed negative trends in tidally restricted marshes (-2.4% annually from 1998 to 2012) but was stable in unrestricted marshes across the same period. At the species level, we found negative population trends in 3 of the 5 specialist species, ranging from -4.2% to 9.0% annually. We suggest that tidal restriction may accelerate degradation of tidal marsh resilience to sea-level rise by limiting sediment supply necessary for marsh accretion, resulting in specialist habitat loss in tidally restricted marshes. Based on our findings, we predict a collapse of the global population of Saltmarsh Sparrows (A. caudacutus) within the next 50 years and suggest that immediate conservation action is needed to prevent extinction of this species. We also suggest mitigation actions to restore sediment supply to coastal marshes to help sustain this ecosystem into the future. Los humedales costeros son uno de los ecosistemas más productivos en el mundo. Consecuentemente, han sido utilizados intensivamente por los humanos durante siglos, resultando en la pérdida del ecosistema. Modificaciones humanas directas como caminos y zanjas, así como agentes climáticos estresantes como el incremento del nivel del mar y eventos de tormentas extremas tienen el potencial de degradar aun más la cantidad y calidad de humedales a lo largo de las costas. Utilizamos una base de datos de 18 años de aves de humedal para generar tendencias poblaciones de especies de aves