Is environmental legislation conserving tropical stream faunas? A large-scale assessment of local, riparian and catchment-scale influences on Amazonian fish.
Is environmental legislation conserving tropical stream faunas? A large-scale assessment of local, riparian and catchment-scale influences on Amazonian fish.
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环境立法是否保护热带溪流动物群？
DOI：
10.1111/1365-2664.13028
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
P. Pompeu
中科院分区：
文献类型：
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作者：
C. G. Leal;J. Barlow;T. Gardner;R. Hughes;R. Leitão;R. M. Nally;P. Kaufmann;S. Ferraz;J. Zuanon;F. R. de Paula;J. Ferreira;J. Thomson;Gareth D. Lennox;E. P. Dary;Cristhiana P. Röpke;P. Pompeu
农业扩张和集约化是对热带生物多样性的主要威胁。除了直接移走原生植被外，农业扩张还常常造成其他人为干扰，而现有环境立法和保护方案对其中许多干扰处理不力。这是特别真实的热带淡水系统，在那里有相当大的不确定性，立法重点保护河岸植被是否足以保护流fanoates.To评估在何种程度上流鱼被有效地保护在农业景观，我们研究了空间分布的集合在河流流域，以确定人类影响的相对重要性在installation，河岸和集水区尺度，形成观察到的模式。我们使用了一个广泛的数据集的生态条件的83个低阶流分布在三个流域在巴西亚马逊河东部。我们收集并确定了24,420个个体的鱼从134种。乘法多样性分区显示高水平的组成相异（DS）之间的流网站（DS = 0.74至0.83）和流域（DS = 0.82），主要是由于营业额（77.8%至81.8%），而不是嵌套。亚马逊河小溪流中高度异质性的鱼类区系强调了制定措施保护公共保护区以外私人土地上的森林的至关重要性。与河岸（2%-12%），集水区（4%-13%）或自然协变量（4%-11%）相比，河流栖息地特征解释了鱼类组合（15%-19%）的变化。虽然将物种分组为功能性行业协会使我们能够解释高达31%的丰度（即游泳食草动物），但通常是环境立法重点的单个河岸和集水区尺度预测变量对观察到的变化解释甚少（部分R2值大多<5%）。目前热带地区农业集约化和机械化的速度是前所未有的，但现有的立法框架侧重于保护河岸植被似乎不足以保护河流环境及其鱼类群落。为了保护亚马孙河小溪流中物种丰富的淡水生物群，保护行动必须转向管理整个流域和排水网络，以及在已清理的土地上进行农业耕作。
Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human-induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna.To assess the extent to which stream fish are being effectively conserved in agricultural landscapes, we examined the spatial distribution of assemblages in river basins to identify the relative importance of human impacts at instream, riparian and catchment scales, in shaping observed patterns. We used an extensive dataset on the ecological condition of 83 low-order streams distributed in three river basins in the eastern Brazilian Amazon.We collected and identified 24,420 individual fish from 134 species. Multiplicative diversity partitioning revealed high levels of compositional dissimilarity (DS) among stream sites (DS = 0.74 to 0.83) and river basins (DS = 0.82), due mainly to turnover (77.8% to 81.8%) rather than nestedness. The highly heterogeneous fish faunas in small Amazonian streams underscore the vital importance of enacting measures to protect forests on private lands outside of public protected areas.Instream habitat features explained more variability in fish assemblages (15%-19%) than riparian (2%-12%), catchment (4%-13%) or natural covariates (4%-11%). Although grouping species into functional guilds allowed us to explain up to 31% of their abundance (i.e. for nektonic herbivores), individual riparian - and catchment - scale predictor variables that are commonly a focus of environmental legislation explained very little of the observed variation (partial R2 values mostly <5%).Policy implications. Current rates of agricultural intensification and mechanization in tropical landscapes are unprecedented, yet the existing legislative frameworks focusing on protecting riparian vegetation seem insufficient to conserve stream environments and their fish assemblages. To safeguard the species-rich freshwater biota of small Amazonian streams, conservation actions must shift towards managing whole basins and drainage networks, as well as agricultural practices in already-cleared land.