Environment for Development Tanzania (EfDT), Department of Economics, University of Dar Es Salaam, Dar Es Salaam, Tanzania.
Environmental Policy Research Unit (EPRU), School of Economics, University of Cape Town, Cape Town, South Africa.
Sci Rep. 2019 Mar 5;9(1):3434. doi: 10.1038/s41598-019-39745-7.
Despite the importance of naturally available wild pollination ecosystem services in enhancing sub-Saharan African smallholder farms' productivity, their values to actual farming systems remain unknown. We develop a nationally representative empirical assessment by integrating nationally representative plot level panel data with spatially and temporally matched land cover maps to identify the contribution of wild pollinators to crop revenue. Our estimation results reveal distinct and robust contributions by natural habitats of wild pollinators - forests - to plot-level crop revenue, where habitats in near proximity to plots contribute much more value than those farther away. When contrasting between pollinator-dependent and pollinator-independent crops, we find that the positive effects emerge only for pollinator-dependent crops, while pollinator-independent crops show no benefits. We conclude the empirical assessment by using our estimates to evaluate changes in crop revenue associated with the actual habitat reduction during 2008-2013. We find that this change in the natural habitats of wild pollinators has reduced crop revenue possibly by as much as 29% (mean) and 4% (median). To our knowledge, this is the first empirical assessment to use nationally representative smallholder farms to assess the value of naturally available wild pollination ecosystem services. Our results magnify the documented benefits of forest conservation, as this preserves pollinators' natural habitats, and by extension its inhabitants, who play an important role in boosting crop yields of nature dependent smallholder farms.
尽管自然存在的野生传粉生态系统服务对于提高撒哈拉以南非洲小农户的生产力非常重要，但它们对实际农业系统的价值仍然未知。我们通过将具有全国代表性的地块水平面板数据与空间和时间匹配的土地覆盖图相结合，开发了一种全国代表性的实证评估，以确定野生传粉者对作物收入的贡献。我们的估计结果表明，野生传粉者的自然栖息地——森林——对地块水平的作物收入有明显而稳健的贡献，靠近地块的栖息地比远离地块的栖息地贡献更大。在对比依赖传粉者和不依赖传粉者的作物时，我们发现这种积极影响仅出现在依赖传粉者的作物中，而不依赖传粉者的作物则没有收益。我们使用我们的估计值来评估 2008-2013 年实际栖息地减少对作物收入的影响，从而对实证评估进行总结。我们发现，野生传粉者自然栖息地的这种变化可能使作物收入减少了 29%（均值）和 4%（中位数）。据我们所知，这是首次使用具有全国代表性的小农户来评估自然存在的野生传粉生态系统服务价值的实证评估。我们的结果放大了森林保护的已有益处，因为这保护了传粉者的自然栖息地，进而保护了其居民，他们在提高依赖自然的小农户的作物产量方面发挥了重要作用。
