Centre for Applied Ecology "Prof. Baeta Neves" (CEABN-InBIO), School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017, Lisbon, Portugal.
CE3C-Centre for Ecology, Evolution and Environmental Changes & CHANGE - Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C2 Piso 5 Campo Grande, 1749-016, Lisbon, Portugal.
J Environ Manage. 2024 Jul;364:121498. doi: 10.1016/j.jenvman.2024.121498. Epub 2024 Jun 18.
Livestock grazing occupies over a quarter of terrestrial land and is prevalent to agroforestry ecosystems, potentially affecting the survival, growth, and density of trees' early developmental stages, such as seeds, seedlings, and saplings. To address the effects of livestock on tree recruitment in the face of ongoing debates about their impacts, we conducted a 33-year meta-analysis in Quercus-dominated agroforestry systems. Our analysis revealed a consistently negative effect of livestock on oak acorns, seedlings, and saplings. Significantly, livestock body size influenced oak regeneration, with small-sized livestock, notably sheep and goats, having a more pronounced negative impact compared to mixed-size systems, mainly involving cattle and sheep. The effects of small-sized livestock were markedly detrimental on acorn survival and seedling/sapling density, although no studies eligible for meta-analysis examined large livestock impacts on acorns. Overall, mixed-size livestock systems, often involving cattle and sheep, lessen the negative effects. Our findings indicate that the body size and foraging behaviors of livestock should be considered for the ecological sustainability of the tree component in agroforestry systems. While protective measures have long been integral to well-managed agroforestry systems, our results underscore the importance of integrating diverse livestock sizes and applying specific protective strategies, particularly for acorns and saplings, to further refine these practices. Future research should expand to underrepresented regions and livestock types to refine global agroforestry management practices.
家畜放牧占据了超过四分之一的陆地，在农林复合生态系统中普遍存在，可能会影响树木早期发育阶段（如种子、幼苗和幼树）的存活、生长和密度。为了应对家畜对树木更新的影响，针对其影响的争论不断，我们在栎属主导的农林复合系统中进行了 33 年的荟萃分析。我们的分析表明，家畜对橡实、幼苗和幼树有一致的负面影响。值得注意的是，家畜体型大小影响橡树的再生，小型家畜（特别是绵羊和山羊）与主要涉及牛和羊的混合体型系统相比，对橡树再生的负面影响更为显著。小型家畜对橡实的存活率和幼苗/幼树密度的影响明显不利，尽管没有符合荟萃分析条件的研究考察大型家畜对橡实的影响。总体而言，混合体型家畜系统（通常涉及牛和羊）减轻了负面影响。我们的研究结果表明，在农林复合系统中，应考虑家畜的体型大小和觅食行为，以实现树木组成部分的生态可持续性。虽然长期以来保护措施一直是管理良好的农林复合系统的组成部分，但我们的研究结果强调了整合不同体型家畜和应用特定保护策略的重要性，特别是针对橡实和幼树，以进一步完善这些实践。未来的研究应扩大到代表性不足的地区和畜种，以完善全球农林复合管理实践。
