Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

First author: Daniel S. Karp; Affiliations: University of California (加利福尼亚大学): Davis, USA

Corresponding author: Daniel S. Karp

The idea that noncrop habitat (非作物生境) enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster (支持) yields has emerged as an agroecological paradigm (农业生态模范). However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators (害虫捕食者), natural enemy (天敌) responses remain heterogeneous (异质性) across studies and effects on pests are inconclusive (不确定的). The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates (捕食率), and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress (压低) yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

非作物生境增强病虫害防治，是一种即能保存生物多样性，又能够保证作物产量的双赢策略，这已经形成了一个农业生态模范。然而，农田周边的非作物生境有时有利于害虫捕食者，而自然天敌响应在不同研究下存在差别，并且对于害虫的影响也是不确定的。不同物种对于非作物生境响应的异质性可能是源于起源上的生物学差异，或者是不同试验下生境和生物控制测量方法的差异所导致的。本文通过全球共6759个地点、132个研究试验的害虫防治数据库将自然天敌和害虫丰度、捕食率及作物损害作为环境组成变量进行研究。作者的研究显示尽管环境组成解释了研究中主要的变异来源，但是害虫和天敌丰度、捕食率、作物损害及产量每一个在不同试验研究中都存在不同的响应模式，有时在几个非作物生境中增强、有时减弱，但在所有的非作物生境中的总体趋势并不一致。因此，利用环境组成变量来预测害虫的防治动态很难解释不同研究下的变异，虽然将类似的作物及环境条件下的研究进行比较时，预测确实提升了准确度。总的来说，本文的工作显示了农田周边的非作物生境并不能总是提升病虫害管理，这意味着生境保护可能在某些系统中能够保证产量，而在另一些系统中却会降低产量。将来对于环境效应是如何受到区域性农田管理的影响以及害虫和天敌的生物学特性的进一步理解将有助于开发出一款提醒农民何时生境保护确实能够代表双赢的工具。

通讯：Daniel S. Karp (http://wfcb.ucdavis.edu/people/faculty/karp-daniel/)

个人简介：2009年，斯坦福大学，生物学和地球系统学士；2013年，斯坦福大学，生态学和演化生物学博士。

研究方向：开发即能保护生物多样性又能维持作物产量的解决方案。

doi: https://doi.org/10.1104/pp.17.01492

Journal: PNAS

Approved: 01 June, 2018

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