Agricultural margins could enhance landscape connectivity for pollinating insects across the Central Valley of California, U.S.A.

One of the defining features of the Anthropocene is eroding ecosystem services as a function of decreases in biodiversity and overall reductions in the abundance of once-common organisms, including many insects that play innumerable roles in natural communities and agricultural systems that support human society. It is now clear that the preservation of insects cannot rely solely on the legal protection of natural areas far removed from the densest areas of human habitation. Instead, a critical challenge moving forward is to intelligently manage areas that include intensively farmed landscapes, such as the Central Valley of California. Here we attempt to meet this challenge with a tool for modeling landscape connectivity for insects (with pollinators in particular in mind) that builds on available information including lethality of pesticides and expert opinion on insect movement. Despite the massive fragmentation of the Central Valley, we find that connectivity is possible, especially utilizing the restoration or improvement of agricultural margins which (in their summed-area) exceed natural areas. Finally, we highlight steps moving forward and the great many knowledge gaps that could be addressed in the field to improve future iterations of our modeling approach.

人类世（Anthropocene）的标志性特征之一，便是生物多样性下降、曾经常见的生物（包括诸多在支撑人类社会的自然群落与农业系统中发挥不计其数作用的昆虫）的丰度整体降低，进而导致生态系统服务功能不断退化。如今已然明确，昆虫的保护无法仅依靠对远离人类聚居最密集区域的自然区域实施法律保护。取而代之的是，未来的一项关键挑战在于对包含集约化农田景观的区域进行智能化管理，例如美国加利福尼亚州中央谷地。本研究尝试借助一款面向昆虫（尤其聚焦传粉昆虫）的景观连通性建模工具来应对这一挑战，该工具依托现有资料构建，涵盖农药的致死效应以及昆虫移动相关的专家研判。尽管加州中央谷地已被高度碎片化，但研究发现连通性仍可实现，尤其是通过修复或优化农田边缘带——这类区域的总面积已超过自然保护区的总面积。最后，本研究梳理了后续研究方向，并指出该领域存在诸多亟待填补的认知空白，可用于优化本建模方法的后续迭代版本。