McCauley Shannon J, Davis Christopher J, Werner Earl E, Robeson Michael S
Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON L5L 1C6, Canada.
Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada.
J Anim Ecol. 2014 Jul;83(4):858-65. doi: 10.1111/1365-2656.12181. Epub 2013 Dec 10.
Species' range sizes are shaped by fundamental differences in species' ecological and evolutionary characteristics, and understanding the mechanisms determining range size can shed light on the factors responsible for generating and structuring biological diversity. Moreover, because geographic range size is associated with a species' risk of extinction and their ability to respond to global changes in climate and land use, understanding these mechanisms has important conservation implications. Despite the hypotheses that dispersal behaviour is a strong determinant of species range areas, few data are available to directly compare the relationship between dispersal behaviour and range size. Here, we overcome this limitation by combining data from a multispecies dispersal experiment with additional species-level trait data that are commonly hypothesized to affect range size (e.g. niche breadth, local abundance and body size.). This enables us to examine the relationship between these species-level traits and range size across North America for fifteen dragonfly species. Ten models based on a priori predictions about the relationship between species traits and range size were evaluated and two models were identified as good predictors of species range size. These models indicated that only two species' level traits, dispersal behaviour and niche breadth were strongly related to range size. The evidence from these two models indicated that dragonfly species that disperse more often and further had larger North American ranges. Extinction and colonization dynamics are expected to be a key linkage between dispersal behaviour and range size in dragonflies. To evaluate how extinction and colonization dynamics among dragonflies were related to range size we used an independent data set of extinction and colonization rates for eleven dragonfly species and assessed the relationship between these populations rates and North American range areas for these species. We found a negative relationship between North American range size and species' extinction-to-colonization ratios. Our results indicate that metapopulation dynamics act to shape the extent of species' continental distributions. These population dynamics are likely to interact with dispersal behaviour, particularly at species range margins, to determine range limits and ultimately species range sizes.
物种的分布范围大小是由物种生态和进化特征的根本差异所塑造的，理解决定分布范围大小的机制能够揭示造成生物多样性产生和结构形成的因素。此外，由于地理分布范围大小与物种的灭绝风险及其应对气候和土地利用全球变化的能力相关，理解这些机制具有重要的保护意义。尽管有假说认为扩散行为是物种分布范围大小的一个重要决定因素，但很少有数据可用于直接比较扩散行为与分布范围大小之间的关系。在此，我们通过将多物种扩散实验的数据与通常被认为会影响分布范围大小的其他物种水平特征数据（如生态位宽度、局域丰度和体型）相结合，克服了这一限制。这使我们能够研究北美15种蜻蜓物种的这些物种水平特征与分布范围大小之间的关系。我们评估了基于物种特征与分布范围大小之间关系的先验预测的10个模型，并确定了两个模型可作为物种分布范围大小的良好预测指标。这些模型表明，只有两个物种水平特征，即扩散行为和生态位宽度与分布范围大小密切相关。这两个模型的证据表明，扩散更频繁、更远的蜻蜓物种在北美有更大的分布范围。灭绝和定殖动态预计是蜻蜓扩散行为与分布范围大小之间的关键联系。为了评估蜻蜓的灭绝和定殖动态与分布范围大小之间的关系，我们使用了11种蜻蜓物种的灭绝和定殖率独立数据集，并评估了这些种群动态率与这些物种在北美的分布范围之间的关系。我们发现北美分布范围大小与物种的灭绝与定殖比率之间存在负相关关系。我们的结果表明，集合种群动态作用于塑造物种大陆分布的范围。这些种群动态可能与扩散行为相互作用，特别是在物种分布范围边缘，以确定分布范围界限并最终确定物种分布范围大小。
