Assessing the effect of visual isolation on the population density of Atlantic salmon (Salmo salar) using GIS
Assessing the effect of visual isolation on the population density of Atlantic salmon (Salmo salar) using GIS
复制标题
使用 GIS 评估视觉隔离对大西洋鲑鱼 (Salmo salar) 种群密度的影响
DOI：
10.1002/rra.1024
复制
发表时间：
2007
影响因子：
2.2
通讯作者：
J. Grant
中科院分区：
文献类型：
--
作者：
I. Dolinsek;P. Biron;J. Grant
很少有研究调查生物对溪流强化方案的行为反应。在增强研究中很少研究的一个行为过程是通过在河床上添加巨石而造成的视觉隔离。这项研究的目的是使用地理信息系统(GIS)视域分析来确定在巨石增加区观察到的大西洋鲑鱼密度增加是否与视觉隔离有关，或者，或者与速度避难所的存在有关。在双体船小溪和小西南米拉米奇河(加拿大新不伦瑞克)建立了八个研究地点。每个范围被分成3个3 m × 2 m的样方。在其中一个样方中，添加36块巨石(D50 = 0.20 m)以增加视觉隔离。巨石被从相邻的另一个样方移走，而第三个样方处于自然状态。利用全站仪建立了详细的数字高程模型(DEM)。在两个夏天，人们通过浮潜多次观察到大西洋鲑鱼。用全站仪记录它们的位置，测量它们的口鼻和平均速度。进行了地理信息系统视域分析，以确定每条鱼的可见区域，并验证周围的鱼是否可见。结果表明，实验样方中观察到的大西洋鲑鱼种群密度增加的主要机制是个体视野的缩小，通过增加栖息地的异质性，这与视觉隔离假说是一致的。三种处理的鲑鱼口鼻速度也没有变化，说明密度的增加不符合速度避难假说。版权所有©2007 John Wiley&Sons，Ltd.
Few studies investigate the behavioural response of organisms to stream enhancement schemes. One behavioural process that is rarely examined in enhancement studies is the visual isolation created by adding boulders on the river bed. The objective of this research is to use a Geographic Information Systems (GIS) viewshed analysis to determine if the increase in density of Atlantic salmon observed in boulder‐added zones is related to visual isolation or, alternatively, the presence of a velocity refuge. Eight study sites were established on Catamaran Brook and Little Southwest Miramichi River (New Brunswick, Canada). Each reach was divided into three quadrats of 3 m × 2 m. In one of the quadrats, 36 boulders (D50 = 0.20 m) were added to increase visual isolation. Boulders were removed from another adjacent quadrat whereas a third quadrat was left in a natural state. A detailed Digital Elevation Model (DEM) was created for all the sites with a total station. Atlantic salmon were observed by snorkelling on several occasions during two summers. Their position was recorded with the total station and the snout and average velocity was measured. A GIS viewshed analysis was performed to determine the visible area for each fish and to verify whether the surrounding fish were visible or not. Results suggest that the primary mechanism responsible for the observed increase in Atlantic salmon population density in the experimental quadrats is a reduction in the field of view of individuals, through an increase in habitat heterogeneity, which is consistent with the visual isolation hypothesis. There was also no change in the snout velocity of salmon among the three treatments, suggesting that the increase in density is not consistent with the velocity‐refuge hypothesis. Copyright © 2007 John Wiley & Sons, Ltd.