Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressur...Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressure independently of precise ungulate population data.This study aimed to determine the regeneration mechanisms of palatable tree species in natural forest ecosystems by measuring the forage abundance from young trees of focal species and estimating the browsing pressure exerted by ungulates.We analyzed an extensive dataset of 2,838 tree saplings in two national parks in Poland to examine relationships between variables using a zero-intercept linear regression,and multiple linear regression models,and performed parametric and nonparametric tests.We found that the browsing intensity index(BI)is a good predictor of browsing pressure.Both total abundance and twig dry mass loss due to ungulate browsing were more pronounced in shorter saplings,with these effects decreasing as sapling height increased.Picea abies was the most abundant browse source in the Tatra National Park(TNP),whereas Fagus sylvatica dominated in the Roztocze National Park(RNP).Acer pseudoplatanus and Sorbus aucuparia experienced significantly higher browsing pressure in the TNP,whereas Carpinus betulus was more heavily browsed than other species in the RNP.The increase in browse abundance rapidly reduced ungulate browsing pressure on highly palatable tree species.We conclude that despite the high browsing pressure on the palatable species,the contribution of browse from focal species helps to mitigate this pressure and supports their regeneration in the forest canopy.Therefore,this finding provides valuable insights for managing and conserving tree species vulnerable to ungulate browsing in natural forest ecosystems.In addition,the method we used in this study is novel to estimate browsing pressure and assess the recruitment potential of vulnerable tree species;hence,it can be applied in large-scale studies with similar scenarios.展开更多
Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies...Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies on human perception, and major emphasis on the saliently similar aspect of objects to be compared is placed and thus the search result is more agreeable for users. After relevant results are obtained, the cluster-based browsing algorithm is adopted for search result presentation based on social network analysis. By organizing the results in clustered lists, the user can have a general understanding of the whole collection by viewing only a small part of results and locate those of major interest rapidly. Experimental results demonstrate the advantages of the proposed algorithm over the traditional work.展开更多
基金funded by Polish National Science Foundation(NCN)(grant No.2018/31/B/NZ8/02786,project title:“How do largescale disturbances influence the relationship between ungulate herbivory and natural regeneration in temperate forests?”)from the Ministry of Science and Higher Education of the Republic of Poland within the framework of statutory activities SUB/040011-D019/2020 of the Department of Forest Biodiversity,University of Agriculture in Krakow.
文摘Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressure independently of precise ungulate population data.This study aimed to determine the regeneration mechanisms of palatable tree species in natural forest ecosystems by measuring the forage abundance from young trees of focal species and estimating the browsing pressure exerted by ungulates.We analyzed an extensive dataset of 2,838 tree saplings in two national parks in Poland to examine relationships between variables using a zero-intercept linear regression,and multiple linear regression models,and performed parametric and nonparametric tests.We found that the browsing intensity index(BI)is a good predictor of browsing pressure.Both total abundance and twig dry mass loss due to ungulate browsing were more pronounced in shorter saplings,with these effects decreasing as sapling height increased.Picea abies was the most abundant browse source in the Tatra National Park(TNP),whereas Fagus sylvatica dominated in the Roztocze National Park(RNP).Acer pseudoplatanus and Sorbus aucuparia experienced significantly higher browsing pressure in the TNP,whereas Carpinus betulus was more heavily browsed than other species in the RNP.The increase in browse abundance rapidly reduced ungulate browsing pressure on highly palatable tree species.We conclude that despite the high browsing pressure on the palatable species,the contribution of browse from focal species helps to mitigate this pressure and supports their regeneration in the forest canopy.Therefore,this finding provides valuable insights for managing and conserving tree species vulnerable to ungulate browsing in natural forest ecosystems.In addition,the method we used in this study is novel to estimate browsing pressure and assess the recruitment potential of vulnerable tree species;hence,it can be applied in large-scale studies with similar scenarios.
基金Supported by the Fund for Basic Research of National Non-Profit Research Institutes(No.XK2012-2,ZD2012-7-2)the Fund for Preresearch Project of ISTIC(No.YY201208)
文摘Similarity matching and this paper, a saliency-based information presentation are two matching algorithm is proposed key factors in information retrieval. In for user-oriented search based on the psychological studies on human perception, and major emphasis on the saliently similar aspect of objects to be compared is placed and thus the search result is more agreeable for users. After relevant results are obtained, the cluster-based browsing algorithm is adopted for search result presentation based on social network analysis. By organizing the results in clustered lists, the user can have a general understanding of the whole collection by viewing only a small part of results and locate those of major interest rapidly. Experimental results demonstrate the advantages of the proposed algorithm over the traditional work.
