From area constraints to functional connectivity: A new framework for ecological regulation in agricultural landscapes

Author of the article:DONG Zhao-Ke1, 2** Lü Zhao-Zhi1, 2

Author's Workplace：1. College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China; 2. Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying 257091, China

Key Words：landscape functional redesign; dynamic functional threshold; non-crop habitats; semi-natural habitat; landscape connectivity; natural pest control; natural enemy conservation

Abstract：Agricultural intensification has resulted in the loss of non-crop habitats and increasing landscape homogenization, thereby undermining natural pest control services in agroecosystems. Conventional landscape-based ecological regulation often relies on habitat area, or proportional thresholds, as planning criteria. Although habitat area remains a fundamental constraint on biodiversity conservation and land allocation, an area-centered paradigm based on isolated patches and static space cannot adequately explain variation in pest-control outcomes across landscape contexts, natural-enemy taxa and farming disturbances. Here, we argue that the key task of farmland landscape design is not only to determine how much habitat is required, but also to organize limited habitats through functional connectivity so that they can continuously support the movement of the natural enemies of pests, resource use, population replenishment, and post-disturbance recovery. We develop a framework centered on functional connectivity and implemented through functional networks to address two linked challenges under area constraints: Spatial compensation and the dynamic maintenance of natural-enemy populations. Habitat amount, functional connectivity, resource continuity, temporal complementarity, and disturbance exposure, jointly determine the level of landscape functional support. We define the dynamic functional threshold as the minimum level of integrated landscape functional support required to achieve a predefined ecological-regulation goal under a given ecological and management context, rather than as a fixed habitat-area proportion. We further emphasize that connectivity is not inherently beneficial at all levels; landscape design should seek selective and context-dependent connectivity that promotes natural enemy dispersal while limiting pest spread and pest-reservoir risks. This framework provides a conceptual and quantifiable basis for ecological regulation, natural pest control, and natural enemy conservation in farmland landscapes with limited land resources.