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您的检索式：作者名="Azim U.Mallik"
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| 1 | Topographic species-habitat associations of tree species in a heterogeneous tropical karst seasonal rain forest, China显示文摘Aims Tropical and subtropical karst forests of south China are under increas-ing pressure from over-exploitation causing widespread habitat degra-dation and biodiversity loss.Previous research has demonstrated that topography,as a proxy for resource availability,plays an important role in shaping tree species distributions in tropical forests.However,the association between growth stages and habitats types has not been considered in this analysis.Our aim was to examine the differences among different habitat types to determine whether tree species show similar species-habitat associations at young and mature life stages.Methods We used multivariate regression tree analysis to examined species-habitat associations among eight topographically defined habitats.The results were tested with a torus-translation test and canonical correspondence analysis(CCA)for 74 species in a 15 ha karst tropi-cal seasonal rain forest at the Nonggang National Natural Reserve in south China.We considered two life stages(young and mature)of trees species that showed a positive association with topography.Important Findings We found marked differences in community characteristics and number of associations among the eight habitats.Of the 74 species subjected to torus-translation test,63 had significant positive and 70 had significant negative associations with one or more of the eight habitats.Positive associations were more frequent in higher elevation habitats and negative associations were more frequent in lower eleva-tion habitats.This suggests that edaphic and hydrological variation related to topography play important roles in habitat partitioning in heterogeneous karst forests.For the 63 tree species with significant positive associations to at least one habitat,40 of them had the same positive association at young and mature life stages.The CCA revealed that the six topographic variables considered had consistent relation-ships with species distribution among all individuals and their two life stages.This indicates that most of the karst forest tree species show consistent associations with a single habitat throughout their life.We conclude that niche differentiation plays an important role in main-taining the diversity of this heterogeneous species-rich karst forest. | Yili Guo Bin Wang Azim U.Mallik Fuzhao Huang Wusheng Xiang Tao Ding Shujun Wen Shuhua Lu Dongxing Li Yunlin He Xiankun Li | 2017 | Journal of Plant Ecology2017，10，3： | 6 |
| 2 | Invaders’ control on post-disturbance succession in coastal mangroves显示文摘Aims In recent years,coastal mangroves have been frequently affected by large disturbances(cyclones,hurricanes,flooding and tsunamis)and post-disturbance vegetation is often dominated by small stature mangrove,mangrove-associate and non-mangrove species potentially affecting ecosystem functioning.Knowledge on the processes of mangrove vegetation development and recovery(succession)following normal and large disturbances will benefit practitioners in designing robust ecosystem management/restoration plans.Here we propose a conceptual model of disturbance-mediated succession in mangroves.Methods Based on field observations and species’life history traits,we develop conceptual models of mangrove succession under normal disturbance regime and recently experienced increased frequency of large disturbances.We evaluate our conceptual models by conducting a scenario testing experiment.Important Findings We suggest two predominant processes affecting mangrove succession after disturbance:propagule limitation due to damage of seed producing mature trees and dispersal barrier resulting from biological invasion associated with large disturbance.We argue that large disturbances affect mature trees more than the small-stature non-tree(shrubs,herbs and climbers)species creating a larger propagule shortage for mangrove tree species than non-tree species.Secondly,large disturbances facilitate invasion of free-floating aquatics,which may interfere with the flow-facilitated propagule dispersal and seedling establishment of mangrove species.In a scenario testing experiment,we have shown that similar levels of disturbance impact vegetation development and recovery differently depending on the presence or absence of invasive species.We conclude that since biological invasion is one of the major drivers of post-disturbance mangrove succession,the dimension of biological invasion should be included in prediction,management and restoration of mangrove forests. | Shekhar R.Biswas Md.Saiful Islam Khan Azim U.Mallik | 2012 | Journal of Plant Ecology2012，5，2： | 0 |
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