General decline of understory cover can result from increased abundance of and foraging pressure by deer.But population size and degree of aggregation can increase for unpalatable understory plants that escape foragin...General decline of understory cover can result from increased abundance of and foraging pressure by deer.But population size and degree of aggregation can increase for unpalatable understory plants that escape foraging pressure.Clonal reproduction can enable unpalatable plant species to increase their population sizes while trending toward spatially aggregated distributions.However,the details of the relationship between clonal reproduction in unpalatable plants and their dynamics under intensive deer herbivory are not clear.We compared the population structures and spatial patterns of two coexisting unpalatable plant species,Arisaema ovale(with clonal reproduction)and A.peninsulae(without clonal reproduction)in a riparian forest intensively grazed by Sika deer,and examined the null hypothesis that the extent of spatial aggregation and local population size would not differ between the clonal and non-clonal Arisaema species.In a 0.36-ha plot,A.ovale had a larger population size(1087 individuals)with a higher abundance ratio of small plants(p<0.01)than A.peninsulae(84 individuals).Analyses of spatial point processes showed that both populations were spatially aggregated(p<0.05).The spatial aggregation of A.peninsulae,however,became weaker than that of A.ovale,when we excluded one dense patch originating from irregular seed dispersion.These results,excluding the aggregated distribution observed in A.peninsulae,suggested a substantial contribution of clonal reproduction to the expansion of the local A.ovale population following intensive grazing by Sika deer.展开更多
To understand the pattern of vigilance behavior in Père David’s deer and its adaptation to human disturbance,we carried out an experiment in the Dafeng Père David’s Deer Nature Reserve.In a large paddock,w...To understand the pattern of vigilance behavior in Père David’s deer and its adaptation to human disturbance,we carried out an experiment in the Dafeng Père David’s Deer Nature Reserve.In a large paddock,we observed vigilance behaviors of free-ranging Père David’s deer.In spring and summer,we used a laser-range finder to measure the alert-distance of the Père David’s deer group in the large paddock.Our data indicate that the vigilance behaviors in Père David’s deer included scanning,stare,walking away,flee,alarm calls and pawing ground for alert.After statistical analysis,we found that:(1)the expression of vigilance behavior in Père David’s deer was depend on intensity of human disturbance;(2)keeping seasonal factors constant,there was a significant difference among different types of alert distances;furthermore,the stare distance was significantly longer than the distance of walking away and fleeing;(3)the stare distance in semi-free ranging Père David’s deer in summer was significantly greater than in spring,but the distances of walking away and the distances of fleeing exhibited no significant difference between the two seasons.These results indicated that:(1)the main factor affecting vigilance behavior in Père David’s deer was human disturbance under the captive breeding situation and(2)Père David’s deer adopted different vigilance behavior in response to human disturbance under different circumstances.In animal conservation,it is important to consider the relationship between vigilance behavior and human disturbance.展开更多
基金funded by a grant from The Yakumo Foundation for Environmental Science(2015,to Y.M.)
文摘General decline of understory cover can result from increased abundance of and foraging pressure by deer.But population size and degree of aggregation can increase for unpalatable understory plants that escape foraging pressure.Clonal reproduction can enable unpalatable plant species to increase their population sizes while trending toward spatially aggregated distributions.However,the details of the relationship between clonal reproduction in unpalatable plants and their dynamics under intensive deer herbivory are not clear.We compared the population structures and spatial patterns of two coexisting unpalatable plant species,Arisaema ovale(with clonal reproduction)and A.peninsulae(without clonal reproduction)in a riparian forest intensively grazed by Sika deer,and examined the null hypothesis that the extent of spatial aggregation and local population size would not differ between the clonal and non-clonal Arisaema species.In a 0.36-ha plot,A.ovale had a larger population size(1087 individuals)with a higher abundance ratio of small plants(p<0.01)than A.peninsulae(84 individuals).Analyses of spatial point processes showed that both populations were spatially aggregated(p<0.05).The spatial aggregation of A.peninsulae,however,became weaker than that of A.ovale,when we excluded one dense patch originating from irregular seed dispersion.These results,excluding the aggregated distribution observed in A.peninsulae,suggested a substantial contribution of clonal reproduction to the expansion of the local A.ovale population following intensive grazing by Sika deer.
文摘To understand the pattern of vigilance behavior in Père David’s deer and its adaptation to human disturbance,we carried out an experiment in the Dafeng Père David’s Deer Nature Reserve.In a large paddock,we observed vigilance behaviors of free-ranging Père David’s deer.In spring and summer,we used a laser-range finder to measure the alert-distance of the Père David’s deer group in the large paddock.Our data indicate that the vigilance behaviors in Père David’s deer included scanning,stare,walking away,flee,alarm calls and pawing ground for alert.After statistical analysis,we found that:(1)the expression of vigilance behavior in Père David’s deer was depend on intensity of human disturbance;(2)keeping seasonal factors constant,there was a significant difference among different types of alert distances;furthermore,the stare distance was significantly longer than the distance of walking away and fleeing;(3)the stare distance in semi-free ranging Père David’s deer in summer was significantly greater than in spring,but the distances of walking away and the distances of fleeing exhibited no significant difference between the two seasons.These results indicated that:(1)the main factor affecting vigilance behavior in Père David’s deer was human disturbance under the captive breeding situation and(2)Père David’s deer adopted different vigilance behavior in response to human disturbance under different circumstances.In animal conservation,it is important to consider the relationship between vigilance behavior and human disturbance.
