Habitat restoration improves Western Snowy Plover nest survival

Productivity measures, such as nest survival rates, are often used to indirectly assess habitat quality and guide management practices for conservation of threatened and endangered species. The Western Snowy Plover Charadrius nivosus nivosus is listed as threatened due to three limiting factors: human disturbance, increasing native and introduced predator populations, and the loss and degradation of habitat. We examined the relative influence of these three limiting factors on nest survival, using 14 years of data (n = 610 nests) at eight sites in Humboldt County, California, USA. Survival varied by year and site, and increased with nest age and as the breeding season progressed. Habitat restoration had the greatest influence on nest survival. Both natural (tidal overwash) and human-implemented restoration had a positive effect on nest survival, whereas unrestored areas had a negative effect. Naturally restored areas had a stronger effect (higher and less variable survival estimates) on nest survival than human-restored areas. Human and predator activity were not strong predictors of nest survival. Consequently, we recommend that managers focus on conserving, maintaining, and creating restoration areas to enhance Snowy Plover nest survival.