Tree crops like cocoa and oil palm have ecological and socio-economic significance in tropical landscapes. However, their expansion in tropical landscapes leaves footprints on ecosystem-based livelihoods, forests, and land for food. While policy and research have focused on productivity, markets and land-use transitions, the structural effects of expanding tree crops on landscapes have rarely been assessed. This study investigates changes in landscape structural properties associated with tree-crop expansion in a smallholder-dominated mosaic landscape. It quantifies the degree of integration/segregation in the landscape, and the direction in which the landscape evolves on an integration-segregation continuum. Landscape metrics from 1986 to 2015 land-cover maps were used to quantify landscape composition and configuration. Selected metrics were combined into a new composite landscape structural state index (LSSI), as a measure to determine the degree of integration/segregation. The study found that landscape composition was relatively stable. However, reduced patch numbers and complexity, and increased connectivity and aggregation revealed configurational dynamics: cocoa and oil palm exhibited aggregation tendencies; while food-crop areas became fragmented; and the LSSI indicated a shift towards greater segregation in the landscape between 1986 and 2015. Regarding structure, the smallholder landscape mimics an industrial agrarian landscape with large segregated homogenous cocoa and oil palm areas, and a reserved forest area. The study thus reveals changes in structural properties due to tree-crop led landscape transitions. It suggests considering these aspects when promoting tree crops in mosaic landscapes as they imply adverse effects on food availability and ecosystem services.

中文翻译：

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整合与隔离：加纳树木作物扩张下小农主导的马赛克景观的结构动态

可可和油棕等树木作物在热带景观中具有生态和社会经济意义。然而，它们在热带景观中的扩张在基于生态系统的生计、森林和食物土地上留下了足迹。虽然政策和研究侧重于生产力、市场和土地利用的转变，但很少评估扩大树木作物对景观的结构性影响。本研究调查了与小农主导的马赛克景观中树木作物扩张相关的景观结构特性的变化。它量化了景观中的整合/隔离程度，以及景观在整合-隔离连续体上演变的方向。1986 年至 2015 年的土地覆盖图的景观指标用于量化景观构成和配置。选定的指标被组合成一个新的复合景观结构状态指数 (LSSI)，作为确定整合/隔离程度的衡量标准。研究发现，景观构成相对稳定。然而，斑块数量和复杂性的减少以及连接和聚集的增加揭示了构型动态：可可和油棕表现出聚集趋势；而粮食作物区变得支离破碎；LSSI 表明 1986 年至 2015 年间，景观向更大程度的隔离转变。在结构方面，小农景观模仿工业农业景观，具有大面积隔离的同质可可和油棕区域，以及保留的森林区域。因此，该研究揭示了由于树木作物导致的景观转变导致的结构特性变化。