摘要
本文对新疆河狸秋季啃伐对策的研究表明,被伐木离水边或食物堆距离(大于50m)越远,河狸的啃伐率越低,而选择性越强,在食物堆附近很少啃伐。新疆河狸最喜啃伐直径为2.5-4.5cm的林木,平均直径为2.57cm。河谷林密度降低,河狸的啃伐密度随之降低,但啃伐率升高。新疆河狸的最佳啃伐范围为离岸边15m以内、距食物堆40-120m的范围。河狸对河谷林的“皆伐式”啃伐、对大直径林木的强度啃伐、到距食物堆150m以外或在食物堆附近大规模啃伐及经常变换越冬洞位置,均因其生境的严重退化。人类活动是造成其生境严重退化的主要原因,禁止砍伐和放牧是河狸保护工作的关键环节。
Three species of willow——Salix turanica, S. caspica and S. triandraconstitute the principal foraging species for the beaver in Xinjiang. Investigations were designed to study the beaver's foraging strategy in fall in theBurgan River Reserve of Xinjiang. As predicted, beavers foraged fewer treesat increasing distance from the river's edge or the food cache and were moreselective to different size of trees. Beavers tended to cut farther in upperreaches than in lower reaches. Trees near the food cache were seldom cut.Trees in the 2.5-4.5cm category were preferred. As the distance from thecentral place increased, beavers tended to cut trees of 3.5-4.5cm in diame-ter. Large and small trees tended to be selected at any distances. It was notedthat the beaver usually cut in a spotty or 'block cutting' way, producingdecided'foraging places'. The cut density was correlated directly with thestand density. On the other hand, the rate of available trees cut was inverselycorrelated with the stand density. The oimum range for beaver's cutting was within 15m from the shore and between 40-120m from the food cache.When beavers cut away almost all the trees with no selectivity within reachof their activities, cut the largest trees heavily, or shift their winter burrowfrequently (1-2 years), it means that it is hard to carry the standing quan-tity of beavers for the habitat. Human activities were the primary factorswhich made the degeneration of the woods. Prohibitting from felling trees andgrazing is the key step in the beaver's conservation.
出处
《林业科学》
EI
CAS
CSCD
北大核心
1993年第4期319-325,共7页
Scientia Silvae Sinicae
关键词
河狸
河谷林
啃伐
保护
Beaver (Castor fiber L.)
Foraging strategy
Food cache
Standing quantity, Conservation
