Impacts of the Northwest Forest Plan on forest composition and bird populations
| Autor: | Benjamin Timothy Phalan, Thomas A. Spies, Matthew G. Betts, Josée S. Rousseau, Joseph M. Northrup, Robert L. Deal, Zhiqiang Yang |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Clearcutting Conservation of Natural Resources 010504 meteorology & atmospheric sciences avian conservation public policy Forest management Population Biodiversity Forests Sustainability Science 010603 evolutionary biology 01 natural sciences Birds Animals early-successional ecosystems Ecosystem education 0105 earth and related environmental sciences education.field_of_study Multidisciplinary geography.geographical_feature_category Agroforestry Bayes Theorem Forestry Biological Sciences 15. Life on land Old-growth forest Adaptive management Genetics Population Geography Disturbance (ecology) bird population trends old-growth forests |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Significance The Northwest Forest Plan (NWFP) ended clearcutting of old-growth forest on federal land across western Washington, Oregon, and California in the early 1990s. We provide a test of how this dramatic change affected bird populations—a commonly used biodiversity indicator. Although the NWFP greatly reduced losses of older forests to logging, losses to wildfire have increased, and declines in birds associated with older forests have amplified. The area of early-seral ecosystems with broadleaf trees stabilized on federal land, but declines continue for some associated species. Creation of early-seral vegetation may be justified in some landscapes where wildfires are mostly suppressed, but should not impede development of older forests, the gradual recovery of which remains critical for the long-term success of the NWFP. The Northwest Forest Plan (NWFP) initiated one of the most sweeping changes to forest management in the world, affecting 10 million hectares of federal land. The NWFP is a science-based plan incorporating monitoring and adaptive management and provides a unique opportunity to evaluate the influence of policy. We used >25 years of region-wide bird surveys, forest data, and land-ownership maps to test this policy’s effect on biodiversity. Clearcutting decreased rapidly, and we expected populations of older-forest–associated birds to stabilize on federal land, but to continue declining on private industrial lands where clearcutting continued. In contrast, we expected declines in early-seral–associated species on federal land because of reduced anthropogenic disturbance since the NWFP. Bayesian hierarchical models revealed that bird species’ population trends tracked changes in forest composition. However, against our expectations, declines of birds associated with older forests accelerated. These declines are partly explained by losses of older forests due to fire on federal land and continued clearcutting elsewhere. Indeed, the NWFP anticipated that reversing declines of older forests would take time. Overall, the early-seral ecosystem area was stable, but declined in two ecoregions—the Coast Range and Cascades—along with early-seral bird populations. Although the NWFP halted clearcutting on federal land, this has so far been insufficient to reverse declines in older-forest–associated bird populations. These findings underscore the importance of continuing to prioritize older forests under the NWFP and ensuring that the recently proposed creation of early-seral ecosystems does not impede the conservation and development of older-forest structure. |
| Databáze: | OpenAIRE |
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