Direct and indirect effects of pine silviculture on the larval occupancy and breeding of declining amphibian species

1. Plantation silviculture is increasing globally and is particularly intensive in temperate coniferous forests, where densely planting trees requires practices common to non-conifer systems that can alter forest floor microhabitat, and potentially threaten amphibian persistence. Most declining amphibian species depend on specific forest microhabitats as terrestrial refugia, but amphibian extirpation associated with tree harvest alone appears unlikely, suggesting that impacts of planting forests on groundcover might better predict recent declines in amphibian occupancy. 2. We repeatedly sampled larval presence or absence of 10 amphibian species native to temperate coniferous forest in the Southeastern United States for one year at 62 isolated wetlands located in either naturally regenerating or planted forest (plantation) to assess three direct ways that planted forests might reduce amphibian breeding site occupancy by: 1) increasing conifer densities, 2) decreasing groundcover, and 3...1. 全球人工林营林（Plantation silviculture）规模持续扩张，在温带针叶林（temperate coniferous forests）中尤为集约。该生境下的高密度植树作业需采用非针叶林经营体系的通用措施，而此类措施可能改变林地表微生境（forest floor microhabitat），并潜在威胁两栖动物存续（amphibian persistence）。多数种群衰退的两栖动物物种依赖特定森林微生境作为陆地避难所（terrestrial refugia）；但仅由林木采伐引发的两栖动物局部灭绝（amphibian extirpation）似乎并不常见，这提示人工林经营对地表覆盖物（groundcover）的影响，或能更好地解释近期两栖动物占用率（amphibian occupancy）的下降趋势。 2. 本研究针对美国东南部温带针叶林原生的10种两栖动物，于为期1年的监测周期内，在62处分别坐落于自然更新林与人工林（plantation）的隔离湿地（isolated wetlands）中开展重复采样，记录其幼体的存在与否情况，以此评估人工林可能通过以下3种直接途径降低两栖动物繁殖位点占用率：1）提升针叶树种群密度；2）降低地表覆盖度；3...