Community resilience through subsidies and millenial-scale human impacts in an island biogeography context

我实验室的研究考察了导致我们在自然界中看到的生物多样性模式的过程。我们越来越多地认识到，这些模式是由气候、物种之间的局部相互作用、栖息地之间个体的分散以及人类对陆地的影响共同驱动的。我们非常熟悉通过林业活动、资源开发和基础设施建设而失去的栖息地，这些快速过程可能会迅速导致景观上生物多样性的变化。气候变化等缓慢但广泛的影响增加了我们对人类对自然的长期影响的认识。较少人意识到的事实是，许多我们认为“原始”的栖息地实际上并不是没有长期受人类影响的。相反，这些景观中的一些似乎对环境的影响非常有弹性，显然已经从这些影响中受益，至少在人类重视的方面是这样。我们目前的重点是人类对不列颠哥伦比亚省中部海岸沿海温带雨林的长期影响。在这里，可以看到长达1.3万年的人类历史，形式包括以前的栖息地(由从附近海洋系统收获的大堆蛤壳组成)，经过文化改造的树木，食物植物，以及令人惊讶的是，在这片沿海温带雨林中有大量的火灾证据。我们的研究表明，这些贝类对土壤化学和随后的森林结构产生了强烈的影响。大火还改变了森林的结构，导致景观中树木的大小和类型发生了变化。我们使用多种技术来探索这些长期的人类影响是如何相互作用来影响景观的。特别是，我们会问这样的问题：废除13000年的管理制度会产生什么影响？与那些没有这些影响的地点相比，人类广泛和长期使用的地点之间的森林结构有何不同？此外，我们还进行了小规模实验，以了解这些模式背后的过程可能会如何影响一般意义上的生态系统：从一个生态系统(例如海洋)到另一个生态系统(例如陆地)的营养补贴如何影响生物多样性？补贴的影响(来自“自然”和贝壳等人类来源)是否改变了我们对岛屿生物多样性预期的经典理解？

Research in my lab examines the processes that give rise to the patterns of biodiversity we see in nature. Increasingly we understand that these patterns are driven by a combination of climate, local interactions between species, dispersal of individuals between habitats, and human impacts on the land. We are very familiar with habitat lost though forestry activities, resource development, and infrastructure creation, fast processes that can rapidly lead to changes in biodiversity on the landscape. Slower but extensive impacts like climate change increase our appreciation of the longer-term impacts of humans on nature. Less appreciated is the fact that many of the habitats that we consider "pristine" are not, in fact, free of long periods of human influence. Instead, some of these landscapes appear to be very resilient to impacts in the environment, and clearly have benefited from these impacts, at least in ways that humans value. Our current focus is on the long-term impacts of humans on coastal temperate rainforests on British Columbia's Central Coast. Here, up to 13,000 years of human history is visible on the landscape in the form of former habitation sites (composed of large heaps of clam shells harvested from the nearby marine system), culturally modified trees, food plants, and surprisingly, extensive fire evidence in this coastal temperate rainforest. Our research has shown strong impacts of these shell middens on soil chemistry and subsequently on forest structure. Fire has also changed the structure of the forest, leading to altered sizes and types of trees on the landscape. We use a combination of techniques to explore how these long-term human impacts interact to impact the landscape. In particular we ask questions like what is the effect of removing 13,000 years of a management regime? How does forest structure differ between sites with extensive and long-term human use, compared to those sites where these effects are absent? Further, we do small-scale experiments to see how the processes behind these patterns might affect ecosystems in a general sense: how do nutrient subsidies from one ecosystem (for example the sea) to another (the land) impact biodiversity? Do the effects of subsidies (from "natural" and human sources like clamshells) change our classic understanding of how much biodiversity to expect on islands ?