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Factors that influence vital rates of Seaside and Saltmarsh sparrows in coastal New Jersey, USA
Citation:
Roberts, S., R. Longenecker, M. Etterson, K. Ruskin, C. Elphick, B. Olsen, AND G. Shriver. Factors that influence vital rates of Seaside and Saltmarsh sparrows in coastal New Jersey, USA. Journal of Field Ornithology. Wiley InterScience, Silver Spring, MD, 88(2):115-131, (2017).
Impact/Purpose:
This manuscript provides demographic and vital rate information for two species of sparrow that nest in saltmarshes of the Eastern USA. Comparative study of the two species show that saltmarsh sparrows are in demographic trouble, whereas seaside sparrows are comparatively safe. Given the many documented threats to saltmarsh habitats in the eastern USA, including sea level rise and habitat degradation and destruction, the paper and analyses described in this paper will prove useful for land managers attempting to preserve the biological attributes of saltmarsh habitats.
Description:
As salt marsh habitat continues to disappear, understanding the factors that influence salt marsh breeding bird population dynamics is an important step towards managing declining wildlife populations. Using five years (2011 2015) of demographic data, we evaluated and compared Seaside (Ammodramus maritimus) and Saltmarsh sparrow (A. caudacutus) adult survival and nest survival within the Edwin B. Forsythe National Wildlife Refuge, New Jersey, USA. We also determined the effect of site management history (unditched vs. ditched marsh) on adult and nest survival to aid in prioritizing future management or restoration actions. Seaside Sparrow adult survival (61.6%, 95% CI: 52.5 70.0%) was 21.7% greater than Saltmarsh Sparrow adult survival (39.9%, 95% CI: 34.0 46.2%). Nest survival, depredation, and flooding rates did not differ between Seaside and Saltmarsh sparrows and depredation was the greatest cause of failure for both species. Adult survival and nest survival did not differ between unditched and ditched marshes for either species, indicating that ditched marshes are not inherently worse breeding habitat for these species. With depredation as the greatest cause of nest failure for both species in New Jersey, we suggest that future research should focus on predator communities within salt marshes and the potential for implementing predator control programs within this habitat.
