BioOne.org will be down briefly for maintenance on 17 December 2024 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
How to translate text using browser tools
4 August 2021 Protected areas safeguard landbird populations in central coastal California: Evidence from long-term population trends
Mark D. Dettling, Kristen E. Dybala, Diana L. Humple, Thomas Gardali
Author Affiliations +
Abstract

Many bird populations have experienced population declines across North America over the past several decades. The establishment of protected areas has been used as a conservation action to maintain or help in the recovery of these populations; however, the effectiveness of protected areas in safeguarding bird populations within their borders from negative impacts to populations in surrounding unprotected areas has rarely been evaluated. Our study aimed to evaluate the effectiveness of protected areas in the San Francisco Bay Area of California for landbirds. We conducted point count surveys along riparian corridors in coastal Marin County in protected areas, predominately national parks, and estimated the population growth rates for 14 species over 23 years. We compared these growth rates to North American Breeding Bird Survey growth rate estimates from the Coastal California and the Northern Pacific Rainforest Bird Conservation Regions, which comprise larger, regional populations. A safeguarding effect was detected for 9 of the 14 species. We expected an effect on species strongly associated with riparian vegetation, which has incurred significant loss and degradation in the region; however, we instead observed benefits to general riparian users that were at least as great as the benefits to strong riparian specialists. We also expected that populations of resident species might benefit more than migrants; however, we found strong support for a safeguarding effect for both groups. Species with increasing growth rates in coastal Marin County protected areas in comparison to regionally stable or decreasing populations demonstrate the potential for protected areas to not only maintain populations despite declines outside their boundaries but also to help them recover from current and previous losses. Continuing long-term monitoring and associated full life cycle research will help identify if and when other drivers (e.g., climate change) may weaken these safeguarding effects, or when additional conservation and management is warranted.

LAY SUMMARY

  • Designating protected areas has long been assumed to be an effective conservation tool and benefit bird populations within their borders, with very few studies evaluating this assumption.

  • We tested the assumption by determining population trends for landbird species in protected areas in central coastal California using point count surveys and comparing our results to regional trends.

  • Nine out of 14 species benefited from being inside protected areas with their population trends being more positive than the regional trends.

  • Our study provides support for the effectiveness of designating protected areas as a conservation tool.

  • We call for expanded long-term monitoring as well as exploration of reasons why the safeguarding effect was not universal and what actions are needed.

Mark D. Dettling, Kristen E. Dybala, Diana L. Humple, and Thomas Gardali "Protected areas safeguard landbird populations in central coastal California: Evidence from long-term population trends," Ornithological Applications 123(4), 1-12, (4 August 2021). https://doi.org/10.1093/ornithapp/duab035
Received: 29 September 2020; Accepted: 11 June 2021; Published: 4 August 2021
KEYWORDS
área protegida
ave terrestre
California
California
landbird
marin
marin
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top