Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America.
PLoS One. 2012;7(9):e43561. doi: 10.1371/journal.pone.0043561. Epub 2012 Sep 5.
I compared physical, chemical and biological characteristics of nine rivers running through three timber harvest regimes to investigate the effects of land use on river ecosystems, to determine whether these corresponded to changes linked with downstream location, and to compare the response of different types of indicator variables. Physical variables changed with downstream location, but varied little with timber harvest. Most chemical variables increased strongly with timber harvest, but not with downstream location. Most biological variables did not vary systematically with either timber harvest or downstream location. Dissolved organic carbon did not vary with timber harvest or downstream location, but correlated positively with salmonid abundance. Nutrient manipulations revealed no general pattern of nutrient limitation with timber harvest or downstream location. The results suggest that chemical variables most reliably indicate timber harvest impact in these systems. The biological variables most relevant to human stakeholders were surprisingly insensitive to timber harvest, however, apparently because of decoupling from nutrient responses and unexpectedly weak responses by physical variables.
我比较了贯穿三种木材采伐制度的九条河流的物理、化学和生物特性，以研究土地利用对河流生态系统的影响，确定这些变化是否与下游位置的变化有关，并比较不同类型指示变量的反应。物理变量随下游位置而变化，但与木材采伐关系不大。大多数化学变量随着木材采伐而强烈增加，但与下游位置无关。大多数生物变量与木材采伐或下游位置都没有系统地变化。溶解有机碳(DOC)与木材采伐或下游位置无关，但与鲑鱼丰度呈正相关。养分处理揭示了木材采伐或下游位置没有普遍的养分限制模式。研究结果表明，化学变量最能可靠地指示这些系统中的木材采伐影响。然而，与人类利益相关者最相关的生物变量对木材采伐的敏感性出人意料地低，这显然是因为与养分响应脱钩，以及物理变量的响应出人意料地弱。
