气候变化领域集成服务门户

As saltmarsh habitat continues to disappear, understanding the factors that influence the population dynamics of saltmarsh breeding birds is an important step in the conservation of these declining species. Using 5 yrs (2011-2015) of demographic data, we evaluated and compared apparent adult survival and nest survival of Seaside (Ammodramus maritimus) and Saltmarsh (A.caudacutus) sparrows at the Edwin B. Forsythe National Wildlife Refuge in New Jersey, USA. We determined the effect of site management history (unditched vs. ditched marshes) on adult and nest survival to aid in prioritizing future management or restoration actions. Apparent adult survival (61.6%, 95% CI: 52.5-70.0%) of Seaside Sparrows averaged > 1.5 times greater than that of Saltmarsh Sparrows (39.9%, 95% CI: 34.0-46.2%). Nest survival and predation and flooding rates did not differ between species, and predation was the primary cause of nest failure for both species. Apparent adult survival and nest survival did not differ between unditched and ditched marshes for either species, indicating that marsh ditching history may not affect the quality of breeding habitat for these species. Because predation was the primary cause of nest failure for both species in New Jersey, we suggest that future studies should focus on identifying predator communities in salt marshes and the potential for implementing predator-control programs to limit population declines.