{"title":"具有微妙环境梯度的天然草原物种替代与过渡带","authors":"Natalia Vercelli, Ilda Entraigas","doi":"10.1071/rj20043","DOIUrl":null,"url":null,"abstract":"Heterogeneity creates borders, limits and contrasts between patches. In turn, this pattern generates new processes. Linked to heterogeneity, ecological systems have limits where layout is essential to understanding system organisation. This study analysed internal heterogeneity in natural grassland using: (1) estimation of species replacement in space, and (2) identification of transitional zones and definition of their ecological features in an extremely flat area of the Flooding Pampa, Argentina. Transition analysis was conducted at three sites; 77 plots in total. In each plot, all species, their cover percentage and the proportion of bare soil were recorded and soil samples (0–20cm depth) measured for pH and electrical conductivity. With floristic data, we explored the relationship between pairwise similarities in community structure and pairwise differences in space, adjusting similarity as a linear or non-linear function of geographical distance. We then conducted a cluster analysis to identify transitional zones, which were associated with large vegetation units described for the Flooding Pampa. Floristic composition in transitional zones was analysed according to the proportions of species and combinations characteristic of the different plant communities. Finally, we synthetised topo-edaphic measured information with a Principal Component Analysis to analyse transitional zone environmental properties. Joining hierarchical classification methods and Indicator Species Analysis for single species and combinations, we highlighted internal heterogeneity, often not noticed in these environments. Rotational livestock grazing contribute to heterogeneity that is typical of these grasslands. Knowledge about transitional zones strongly supports the development of management strategies to prevent grassland degradation.","PeriodicalId":20810,"journal":{"name":"Rangeland Journal","volume":"18 1","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Species replacement and transitional zones in natural grasslands with subtle environmental gradations\",\"authors\":\"Natalia Vercelli, Ilda Entraigas\",\"doi\":\"10.1071/rj20043\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Heterogeneity creates borders, limits and contrasts between patches. In turn, this pattern generates new processes. Linked to heterogeneity, ecological systems have limits where layout is essential to understanding system organisation. This study analysed internal heterogeneity in natural grassland using: (1) estimation of species replacement in space, and (2) identification of transitional zones and definition of their ecological features in an extremely flat area of the Flooding Pampa, Argentina. Transition analysis was conducted at three sites; 77 plots in total. In each plot, all species, their cover percentage and the proportion of bare soil were recorded and soil samples (0–20cm depth) measured for pH and electrical conductivity. With floristic data, we explored the relationship between pairwise similarities in community structure and pairwise differences in space, adjusting similarity as a linear or non-linear function of geographical distance. We then conducted a cluster analysis to identify transitional zones, which were associated with large vegetation units described for the Flooding Pampa. Floristic composition in transitional zones was analysed according to the proportions of species and combinations characteristic of the different plant communities. Finally, we synthetised topo-edaphic measured information with a Principal Component Analysis to analyse transitional zone environmental properties. Joining hierarchical classification methods and Indicator Species Analysis for single species and combinations, we highlighted internal heterogeneity, often not noticed in these environments. Rotational livestock grazing contribute to heterogeneity that is typical of these grasslands. Knowledge about transitional zones strongly supports the development of management strategies to prevent grassland degradation.\",\"PeriodicalId\":20810,\"journal\":{\"name\":\"Rangeland Journal\",\"volume\":\"18 1\",\"pages\":\"\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2021-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Rangeland Journal\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://doi.org/10.1071/rj20043\",\"RegionNum\":4,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"ECOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Rangeland Journal","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1071/rj20043","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ECOLOGY","Score":null,"Total":0}
Species replacement and transitional zones in natural grasslands with subtle environmental gradations
Heterogeneity creates borders, limits and contrasts between patches. In turn, this pattern generates new processes. Linked to heterogeneity, ecological systems have limits where layout is essential to understanding system organisation. This study analysed internal heterogeneity in natural grassland using: (1) estimation of species replacement in space, and (2) identification of transitional zones and definition of their ecological features in an extremely flat area of the Flooding Pampa, Argentina. Transition analysis was conducted at three sites; 77 plots in total. In each plot, all species, their cover percentage and the proportion of bare soil were recorded and soil samples (0–20cm depth) measured for pH and electrical conductivity. With floristic data, we explored the relationship between pairwise similarities in community structure and pairwise differences in space, adjusting similarity as a linear or non-linear function of geographical distance. We then conducted a cluster analysis to identify transitional zones, which were associated with large vegetation units described for the Flooding Pampa. Floristic composition in transitional zones was analysed according to the proportions of species and combinations characteristic of the different plant communities. Finally, we synthetised topo-edaphic measured information with a Principal Component Analysis to analyse transitional zone environmental properties. Joining hierarchical classification methods and Indicator Species Analysis for single species and combinations, we highlighted internal heterogeneity, often not noticed in these environments. Rotational livestock grazing contribute to heterogeneity that is typical of these grasslands. Knowledge about transitional zones strongly supports the development of management strategies to prevent grassland degradation.
期刊介绍:
The Rangeland Journal publishes original work that makes a significant contribution to understanding the biophysical, social, cultural, economic, and policy influences affecting rangeland use and management throughout the world. Rangelands are defined broadly and include all those environments where natural ecological processes predominate, and where values and benefits are based primarily on natural resources.
Articles may present the results of original research, contributions to theory or new conclusions reached from the review of a topic. Their structure need not conform to that of standard scientific articles but writing style must be clear and concise. All material presented must be well documented, critically analysed and objectively presented. All papers are peer-reviewed.
The Rangeland Journal is published on behalf of the Australian Rangeland Society.