Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, 2003 Upper Buford Circles, St Paul, MN 55108, USA.
Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, Canada, R3T 2N2.
Proc Biol Sci. 2023 Nov 8;290(2010):20231377. doi: 10.1098/rspb.2023.1377.
Predators can directly and indirectly alter the foraging behaviour of prey through direct predation and the risk of predation, and in doing so, initiate indirect effects that influence myriad species and ecological processes. We describe how wolves indirectly alter the trajectory of forests by constraining the distance that beavers, a central place forager and prolific ecosystem engineer, forage from water. Specifically, we demonstrate that wolves wait in ambush and kill beavers on longer feeding trails than would be expected based on the spatio-temporal availability of beavers. This pattern is driven by temporal dynamics of beaver foraging: beavers make more foraging trips and spend more time on land per trip on longer feeding trails that extend farther from water. As a result, beavers are more vulnerable on longer feeding trails than shorter ones. Wolf predation appears to be a selective evolutionary pressure propelled by consumptive and non-consumptive mechanisms that constrain the distance from water beavers forage, which in turn limits the area of forest around wetlands, lakes and rivers beavers alter through foraging. Thus, wolves appear intricately linked to boreal forest dynamics by shaping beaver foraging behaviour, a form of natural disturbance that alters the successional and ecological states of forests.
捕食者可以通过直接捕食和被捕食的风险，直接或间接地改变猎物的觅食行为，从而引发间接影响，影响众多物种和生态过程。我们描述了狼如何通过限制海狸（一种集中觅食者和多产的生态工程师）从水中觅食的距离，间接地改变森林的轨迹。具体来说，我们证明狼会在更长的觅食路径上埋伏并杀死海狸，这比根据海狸的时空可用性预期的要长。这种模式是由海狸觅食的时间动态驱动的：海狸在更长的觅食路径上会进行更多的觅食旅行，并且每次旅行在陆地上花费的时间更多，这些路径会延伸得更远。因此，海狸在更长的觅食路径上比在更短的路径上更容易受到攻击。狼的捕食似乎是一种由消耗性和非消耗性机制驱动的选择性进化压力，这些机制限制了海狸从水中觅食的距离，从而限制了海狸通过觅食改变的湿地、湖泊和河流周围的森林面积。因此，狼通过塑造海狸的觅食行为与北方森林的动态紧密相连，这种自然干扰形式改变了森林的演替和生态状态。
