Guidance on spatial sampling designs and data reusability in agroforestry research
Eva-Maria L. Minarsch, Vera Marlene Thoß, Lukas Beule
Abstract
Abstract Agroforestry systems are multifunctional land-use systems with a large variety of spatial configurations. The intentional combination of woody perennials (e.g. trees) and agriculture on the same land creates unique interactions between different components of agroforestry systems (e.g. tree-crop interactions), which are key to their environmental benefits and reinforce spatial heterogeneity. Capturing spatial heterogeneity within agroforestry systems is considered crucial for data collection in agronomic and ecological research but poses major challenges for the selection of appropriate spatial sampling designs. This is particularly challenging in agroforestry systems that feature a low degree of spatial organization and/or irregularly shaped agroforestry components. Likewise, identification of suitable reference land-use systems for agroforestry (e.g. agricultural land without trees or forests) and the selection of an appropriate spatial sampling design faces several hurdles but is key for the evaluation of the environmental and economic performance of agroforestry. Here, we provide recommendations to guide the selection of spatial sampling designs within temperate and tropical agroforestry systems with a focus on transect sampling to capture spatial gradients of agronomic and ecological variables within agroforestry systems. We present considerations for delineating transects (point transects and transect walks) within agroforestry systems as well as selecting sampling positions along point transects. We further discuss criteria for the selection of reference land-use systems for agroforestry to study land-use change and provide recommendations for sampling designs within them. Finally, we list recommended key information of the study site, agroforestry system, and spatial sampling design to report to ensure data reusability in agroforestry research.