Baecher J Alex, Richter Stephen C
Department of Biological Sciences and Division of Natural Areas Eastern Kentucky University Richmond Kentucky.
Ecol Evol. 2018 Dec 4;8(24):12940-12952. doi: 10.1002/ece3.4736. eCollection 2018 Dec.
Woodland salamanders are among the most abundant vertebrate animals in temperate deciduous forests of eastern North America. Because of their abundance, woodland salamanders are responsible for the transformation of nutrients and translocation of energy between highly disparate levels of trophic organization: detrital food webs and high-order predators. However, the spatial extent of woodland salamanders' role in the ecosystem is likely contingent upon the distribution of their biomass throughout the forest. We sought to determine if natural environmental gradients influence the fine-scale distribution and density of Southern Ravine Salamanders () and Cumberland Plateau Salamanders (). We addressed this objective by constructing occupancy, co-occurrence, and abundance models from temporally replicated surveys within an old-growth forest in the Cumberland Plateau region of Kentucky. We found that had a more restricted fine-scale distribution than (mean occupancy probability [ ] = 0.737) and exhibited variable density, from <250 to >1000 individuals per hectare, associated with increased soil moisture and reduced solar exposure due to slope face. While more ubiquitously distributed ( = 0.95), density varied from <400 to >1,000 individuals per hectare and was inversely related to increased solar exposure from canopy disturbance and landscape convexity. Our data suggest co-occurrence patterns of and are influenced primarily by abiotic conditions within the forest, and that populations likely occur independently and without evidence of biotic interaction. Given the critical role that woodland salamanders play in the maintenance of forest health, regions that support large populations of woodland salamanders, such as those highlighted in this study-mesic forest stands on north-to-east facing slopes with dense canopy and abundant natural cover, may provide enhanced ecosystem services and support the stability of the total forest.
林地蝾螈是北美东部温带落叶林中数量最为丰富的脊椎动物之一。由于数量众多，林地蝾螈在营养物质转化以及营养组织差异极大的不同层级之间的能量转移过程中发挥着作用，这些层级包括碎屑食物网和高级捕食者。然而，林地蝾螈在生态系统中所发挥作用的空间范围可能取决于其生物量在整个森林中的分布情况。我们试图确定自然环境梯度是否会影响南部峡谷蝾螈（ ）和坎伯兰高原蝾螈（ ）的精细尺度分布和密度。我们通过在肯塔基州坎伯兰高原地区的一片原始森林内进行的时间重复调查构建占有率、共存和丰度模型，来实现这一目标。我们发现， 的精细尺度分布比 更受限制（平均占有率概率[ ] = 0.737），并且密度变化较大，每公顷从不到250只到超过1000只不等，这与坡面土壤湿度增加和日照减少有关。虽然 的分布更为广泛（ = 0.95），但其密度每公顷从不到400只到超过1000只不等，并且与树冠干扰和景观凸度导致的日照增加呈负相关。我们的数据表明， 和 的共存模式主要受森林内非生物条件的影响，而且种群可能独立存在，没有生物相互作用的证据。鉴于林地蝾螈在维持森林健康方面发挥的关键作用，那些支持大量林地蝾螈种群的地区，比如本研究中所强调的——北至东向斜坡上的中生林分，树冠茂密且自然覆盖丰富，可能会提供增强的生态系统服务，并支持整个森林的稳定性。
