Tropical regions are biodiversity hotspots and are well-suited to explore the potential influence of global climate change on forest ecosystems. Bryophytes have essential ecological functions in tropical forest ecosys...Tropical regions are biodiversity hotspots and are well-suited to explore the potential influence of global climate change on forest ecosystems. Bryophytes have essential ecological functions in tropical forest ecosystems, but knowledge of the potential impact of global warming and possible changes in water availability patterns on terrestrial bryophytes is limited. We transplanted eight terres- trial moss species from two elevations (900 and 500 m) to warmer and drier elevations (500 and 100 m) during a halfyear observation period on Tai Mo Shan, southern China. The simulated climate change resulted in severely declined health status and marked decrease in growth of the trans- planted species when compared with their performance at the original elevations. Five of the eight selected species survived for six months after being transplanted to the warmer and drier lowlands, though their health status deteriorated severely. Sematophyllum subhumile , Pseudotaxiphyllum pohliaecarpum and Brachythecium buchananii were highly susceptible to changes in temperature and rainfall patterns and might be used as suitable bioindicators. As the tropics are expected to become hotter and drier, terrestrial mosses might be negatively affected or even be at risk of extinction. Bryophytes in the tropics could represent one of the best biological communities to reflect the direct adverse impact of climate change and provide early warning of the biological outcomes induced by ongoing climate crisis.展开更多
Background:Communal roosting is a common avian social behaviour,which potentially provides foraging benefits,predation avoidance or thermoregulation in birds.To identify the crucial environmental factors associated wi...Background:Communal roosting is a common avian social behaviour,which potentially provides foraging benefits,predation avoidance or thermoregulation in birds.To identify the crucial environmental factors associated with roost site selection,most studies have focused on the comparison of physical characteristics between roosts and non-roosts.However,the differences among roosts have usually been neglected and the causes of roost switching have seldom been investigated.Methods:To explore the variations among roost sites and assess the most influential environmental factors related to seasonal roost switching,we conducted a 105-day observation on an introduced population of critically endan-gered Yellow-crested Cockatoo(Cacatua sulphurea)in an urban environment in Hong Kong from 2014 to 2016.We identified seven roost sites that were occupied in different seasons and then measured their microhabitat character-istics in terms of land use types,human disturbance and microclimate temperature.To quantify these differences,we used Pearson’s chi-squared test,partial least squares determinant analysis(PLS-DA)and one-way repeated measures ANOVA,respectively.Results:Our results distinguished roost sites occupied in three seasons,i.e.spring,summer and winter roosts,using several microhabitat characteristics.The land use types were significantly associated with roosts,where spring roosts were usually located in tree-dominated areas,which are the major feeding grounds.The discriminant analysis on human disturbance variables indicated that summer roosts were positively associated with night illumination.The microhabitat temperatures of winter roosts were significantly higher than those of most other roosts on cold nights.Conclusions:The results highlighted significant variations among roosts,and seasonal roost switching was likely driven by specific microhabitat characteristics of each roost site,such as microclimate.It also helps us understand the behavioural adaptation of birds to urban environments.展开更多
文摘Tropical regions are biodiversity hotspots and are well-suited to explore the potential influence of global climate change on forest ecosystems. Bryophytes have essential ecological functions in tropical forest ecosystems, but knowledge of the potential impact of global warming and possible changes in water availability patterns on terrestrial bryophytes is limited. We transplanted eight terres- trial moss species from two elevations (900 and 500 m) to warmer and drier elevations (500 and 100 m) during a halfyear observation period on Tai Mo Shan, southern China. The simulated climate change resulted in severely declined health status and marked decrease in growth of the trans- planted species when compared with their performance at the original elevations. Five of the eight selected species survived for six months after being transplanted to the warmer and drier lowlands, though their health status deteriorated severely. Sematophyllum subhumile , Pseudotaxiphyllum pohliaecarpum and Brachythecium buchananii were highly susceptible to changes in temperature and rainfall patterns and might be used as suitable bioindicators. As the tropics are expected to become hotter and drier, terrestrial mosses might be negatively affected or even be at risk of extinction. Bryophytes in the tropics could represent one of the best biological communities to reflect the direct adverse impact of climate change and provide early warning of the biological outcomes induced by ongoing climate crisis.
基金supported by the Hong Kong Environment and Conservation Fund(ECF Project 02/2014)the United College Endowment Fund of The Chinese University of Hong Kong.
文摘Background:Communal roosting is a common avian social behaviour,which potentially provides foraging benefits,predation avoidance or thermoregulation in birds.To identify the crucial environmental factors associated with roost site selection,most studies have focused on the comparison of physical characteristics between roosts and non-roosts.However,the differences among roosts have usually been neglected and the causes of roost switching have seldom been investigated.Methods:To explore the variations among roost sites and assess the most influential environmental factors related to seasonal roost switching,we conducted a 105-day observation on an introduced population of critically endan-gered Yellow-crested Cockatoo(Cacatua sulphurea)in an urban environment in Hong Kong from 2014 to 2016.We identified seven roost sites that were occupied in different seasons and then measured their microhabitat character-istics in terms of land use types,human disturbance and microclimate temperature.To quantify these differences,we used Pearson’s chi-squared test,partial least squares determinant analysis(PLS-DA)and one-way repeated measures ANOVA,respectively.Results:Our results distinguished roost sites occupied in three seasons,i.e.spring,summer and winter roosts,using several microhabitat characteristics.The land use types were significantly associated with roosts,where spring roosts were usually located in tree-dominated areas,which are the major feeding grounds.The discriminant analysis on human disturbance variables indicated that summer roosts were positively associated with night illumination.The microhabitat temperatures of winter roosts were significantly higher than those of most other roosts on cold nights.Conclusions:The results highlighted significant variations among roosts,and seasonal roost switching was likely driven by specific microhabitat characteristics of each roost site,such as microclimate.It also helps us understand the behavioural adaptation of birds to urban environments.
