Data from: Ecosystem-scale impacts of non-timber forest product harvesting: effects on soil nutrients

1. The harvesting of non-timber forest products (NTFPs) is a global
phenomenon, the sustainability of which has been studied for many species
at the individual and population level. However, the broader scale impacts
of NTFP harvesting have been acknowledged but rarely examined. 2. We
assessed plant size and the soil attributes undercanopy and in the open,
in replicate, paired harvested and non-harvested sites for three NTFPs
differing in the extent of biomass removed, i.e. timber for firewood from
a tree (Acacia karroo), fruits from a cactus (Opunita ficus-indica) and
flowering culms from a grass (Cymbopogon marginatus). Soil variables
tested included pH, resistivity, P, total N, nitrate nitrogen, ammonium
nitrogen, K, Na, Ca and Mg. 3. The extent of loss of soil nutrients
decreased across the three NTFPs relative to the proportion of biomass
removed. Thus, significant differences in more soil variables were evident
for the firewood species, least for the fruit species and intermediate for
the grass species. Lower soil pH, P, C and K were evident in soils
collected underneath A. karroo, whilst losses in cations of Na, Ca and Mg
were reported in soils underneath C. marginatus, and only NO3N losses were
recorded underneath O. ficus-indica. 4. Synthesis and applications. Our
study reveals that whilst non-timber forest product (NTFP) harvesting may
affect soil nutrients, this is not uniform between species and is likely
to be a function of the extent of biomass removed and harvesting
frequency. This indicates the need for caution in generalisations about
the ecosystem-level impacts of NTFP harvesting as well as a concerted
effort to better understand impacts at a greater range of scales than has
been the case to date.09-Feb-2017

1. 非木材林产品（non-timber forest products, NTFPs）的采集是一种全球性现象，其可持续性已在个体和种群层面针对多种物种展开研究。然而，NTFP采集的更大尺度影响虽已得到认可，却鲜少被深入探讨。 2. 我们在重复设置的配对采集与未采集样点中，评估了三种生物量移除程度不同的NTFP对应的植物大小及林下与开阔地的土壤属性——即来自卡罗相思树（Acacia karroo）的薪材木材、来自印度无花果仙人掌（Opunita ficus-indica）的果实，以及来自缘毛香茅（Cymbopogon marginatus）的开花秆。检测的土壤变量包括pH值、电阻率、磷（P）、全氮（total N）、硝态氮、铵态氮、钾（K）、钠（Na）、钙（Ca）和镁（Mg）。 3. 土壤养分的流失程度随三种NTFP生物量移除比例的降低而减少。因此，薪材物种对应的土壤变量差异更为显著，果实物种最少，草本物种居中。卡罗相思树（A. karroo）林下土壤的pH值、磷（P）、碳（C）和钾（K）含量更低；缘毛香茅（C. marginatus）林下土壤则出现钠（Na）、钙（Ca）和镁（Mg）等阳离子流失；而印度无花果仙人掌（O. ficus-indica）林下仅检测到硝态氮（NO3N）流失。 4. 综合与应用。本研究表明，尽管非木材林产品（NTFP）采集可能影响土壤养分，但其效应在物种间并不一致，且可能与生物量移除程度及采集频率相关。这提示，在对NTFP采集的生态系统尺度影响进行泛化时需谨慎，并需协同努力以更好地理解比目前更广泛尺度下的影响。2017年2月9日