Rivers of the Anthropocene
Rivers of the Anthropocene
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DOI：
10.1890/1540-9295-12.8.427
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发表时间：
2014-10
影响因子：
10.3
通讯作者：
N. L. Poff
中科院分区：
文献类型：
--
作者：
N. L. Poff
古希腊哲学家赫拉克利特（Heraclitus）有一句名言：一个人永远不会两次踏入同一条河流，从而为生命的不断变化提供了一个物理隐喻。近几个世纪以来，人类人口的增长和技术的进步无疑改变了河流。从科学的角度来看，赫拉克利特的格言从来没有像现在这样恰当，在所谓的“人类世”的黎明。河流是极其复杂的生物物理系统。可观察到的生态模式反映了时间上平均的，空间上分布的，多尺度的过程所产生的流域控制降水，侵蚀和营养物质输入到河道。水生和河岸物种和群落反映了适应动态和异质环境的长期进化历史，这些环境通过流动和基因交换发生的通道网络在水文上相连。河流的生态复杂性已被科学地概念化，将这些系统视为存在于一种动态平衡或平衡中，由现行的水文气候和流域控制以及进化物种库定义。人类的行动破坏了这种平衡的组成部分，造成“影响“，这些影响被量化为河流生物物理过程和模式与某些未受干扰的基线条件之间可测量的偏差。人类对河流的影响是广泛和普遍的。也许没有什么地方比土地使用变化（例如城市化，森林砍伐）和跨渠道的水利基础设施更能观察到这一点。水坝通过改变下游的水、沉积物和营养物质的流量，改变水温，阻止物种移动，极大地改变了河流。它们无处不在;仅在美国，就有75000座高度超过2米的水坝，平均每沿着中型河流50公里就有一座。在美国，只有42条河流的未建坝河段超过200公里。在全球范围内，已经建造了40 000多座大型水坝（高度>15米），并计划建造数千座，主要是在发展中国家，通过水力发电生产所谓的“绿色能源“。有越来越多的社会利益，“恢复”调节河流故意释放水库水从大坝，以提供更多的参考样流动条件下游。例如，在科罗拉多河系统中进行的实验性水流释放，例如最近从亚利桑那州的莫雷洛斯大坝向下游接近干涸的墨西哥河床的水流脉动（Science 2014; 343：1301），代表了恢复一些历史生态系统功能的努力。然而，这种努力的效力是有限的。对与大型水坝相关的系统进行物理化学修改，再加上人类辅助的…
T he ancient Greek philosopher Heraclitus famously asserted that one can never step into the same river twice, thus providing a physical metaphor for life's constant change. The growth in human population and advances in technology in recent centuries have certainly changed rivers. From a scientific perspective, Heraclitus' dictum has never been more apt than now, at the dawn of the so-called " Anthropocene ". Rivers are exceedingly complex biophysical systems. Observable ecological patterns reflect temporally averaged, spatially distributed, multi-scaled processes arising from watershed controls on precipitation, erosion, and nutrient inputs into river channels. Aquatic and riparian species and communities reflect a long evolutionary history of adaptations to dynamic and heterogeneous environments that are hydrologically connected via channel networks through which movement and gene exchange occur. Ecological complexity in rivers has been conceptualized scientifically by viewing these systems as existing in a kind of dynamic equilibrium, or balance, defined by prevailing hydro-climatic and watershed controls and by evolutionary species pools. Humans act to disrupt components of this equilibrium, causing " impacts " that are quantified as measurable deviations in riverine biophysical processes and patterns from some unperturbed baseline condition. Human impacts on rivers are extensive and pervasive. Perhaps nowhere is this better observed than in the case of land-use change (eg urbanization, deforestation) and channel-spanning water infrastructure. Dams dramatically transform rivers by altering the downstream flux of water, sediment, and nutrients, modifying water temperatures, and blocking species movement. They are ubiquitous; in the US alone, there are 75 000 dams exceeding 2 m in height, one on average for every 50 km along mid-sized rivers. Only 42 rivers in the US have undammed reaches greater than 200 km. On a global scale, over 40 000 large dams (>15 m in height) have been built and thousands more are proposed, chiefly in developing countries, to produce so-called " green energy " via hydropower. There is growing societal interest in " restoring " regulated rivers by deliberately releasing reservoir water from dams to provide more reference-like flow conditions downstream. For example, experimental flow releases in the Colorado River system, such as the recent pulse of water from Arizona's Morelos Dam into the near dry downstream Mexican riverbed (Science 2014; 343: 1301), represent efforts to regain some historical ecosystem function. There are limits to the effectiveness of such efforts, however. The physical–chemical modifications to systems associated with larger dams, combined with the human-assisted …