16 resultados para Reciprocal patchiness of resources
Filtro por publicador
- KUPS-Datenbank - Universität zu Köln - Kölner UniversitätsPublikationsServer (1)
- Repository Napier (1)
- Aberystwyth University Repository - Reino Unido (3)
- Academic Research Repository at Institute of Developing Economies (1)
- AMS Tesi di Dottorato - Alm@DL - Università di Bologna (10)
- AMS Tesi di Laurea - Alm@DL - Università di Bologna (2)
- Aquatic Commons (39)
- Archimer: Archive de l'Institut francais de recherche pour l'exploitation de la mer (1)
- Archive of European Integration (24)
- Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco (11)
- Aston University Research Archive (37)
- Avian Conservation and Ecology - Eletronic Cientific Hournal - Écologie et conservation des oiseaux: (3)
- Biblioteca de Teses e Dissertações da USP (1)
- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (8)
- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP) (1)
- Biblioteca Digital de la Universidad Católica Argentina (4)
- Biblioteca Digital de Teses e Dissertações Eletrônicas da UERJ (41)
- BORIS: Bern Open Repository and Information System - Berna - Suiça (27)
- Boston University Digital Common (2)
- Brock University, Canada (3)
- Bucknell University Digital Commons - Pensilvania - USA (3)
- Bulgarian Digital Mathematics Library at IMI-BAS (3)
- CaltechTHESIS (2)
- Cambridge University Engineering Department Publications Database (9)
- CentAUR: Central Archive University of Reading - UK (34)
- Chinese Academy of Sciences Institutional Repositories Grid Portal (13)
- CiencIPCA - Instituto Politécnico do Cávado e do Ave, Portugal (1)
- Cochin University of Science & Technology (CUSAT), India (7)
- Comissão Econômica para a América Latina e o Caribe (CEPAL) (23)
- CORA - Cork Open Research Archive - University College Cork - Ireland (3)
- Corvinus Research Archive - The institutional repository for the Corvinus University of Budapest (5)
- Dalarna University College Electronic Archive (4)
- Deakin Research Online - Australia (78)
- DI-fusion - The institutional repository of Université Libre de Bruxelles (3)
- Digital Archives@Colby (1)
- Digital Commons - Michigan Tech (3)
- Digital Commons @ DU | University of Denver Research (2)
- Digital Commons at Florida International University (9)
- DigitalCommons - The University of Maine Research (1)
- DigitalCommons@The Texas Medical Center (9)
- DigitalCommons@University of Nebraska - Lincoln (1)
- Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland (1)
- DRUM (Digital Repository at the University of Maryland) (2)
- Duke University (3)
- Ecology and Society (1)
- eResearch Archive - Queensland Department of Agriculture; Fisheries and Forestry (9)
- Escola Superior de Educação de Paula Frassinetti (1)
- FUNDAJ - Fundação Joaquim Nabuco (1)
- Glasgow Theses Service (2)
- Greenwich Academic Literature Archive - UK (1)
- Helda - Digital Repository of University of Helsinki (27)
- Illinois Digital Environment for Access to Learning and Scholarship Repository (1)
- Indian Institute of Science - Bangalore - Índia (44)
- Institutional Repository of Leibniz University Hannover (1)
- Instituto Politécnico de Bragança (1)
- Instituto Politécnico do Porto, Portugal (2)
- Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States (1)
- Memoria Académica - FaHCE, UNLP - Argentina (3)
- Memorial University Research Repository (1)
- National Center for Biotechnology Information - NCBI (12)
- Plymouth Marine Science Electronic Archive (PlyMSEA) (3)
- Portal de Revistas Científicas Complutenses - Espanha (2)
- Publishing Network for Geoscientific & Environmental Data (6)
- QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast (38)
- Queensland University of Technology - ePrints Archive (164)
- Repositorio Académico de la Universidad Nacional de Costa Rica (3)
- Repositório Alice (Acesso Livre à Informação Científica da Embrapa / Repository Open Access to Scientific Information from Embrapa) (3)
- Repositório Científico da Universidade de Évora - Portugal (4)
- Repositório digital da Fundação Getúlio Vargas - FGV (9)
- Repositório Digital da UNIVERSIDADE DA MADEIRA - Portugal (1)
- Repositório Institucional da Universidade de Aveiro - Portugal (2)
- Repositorio Institucional de la Universidad de Málaga (1)
- Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho" (24)
- RUN (Repositório da Universidade Nova de Lisboa) - FCT (Faculdade de Cienecias e Technologia), Universidade Nova de Lisboa (UNL), Portugal (3)
- SAPIENTIA - Universidade do Algarve - Portugal (4)
- School of Medicine, Washington University, United States (2)
- Scielo España (1)
- Universidad de Alicante (5)
- Universidad del Rosario, Colombia (4)
- Universidad Politécnica de Madrid (16)
- Universidade Complutense de Madrid (3)
- Universidade de Lisboa - Repositório Aberto (1)
- Universidade Federal do Pará (2)
- Universitat de Girona, Spain (1)
- Universitätsbibliothek Kassel, Universität Kassel, Germany (4)
- Université de Lausanne, Switzerland (1)
- Université de Montréal, Canada (7)
- Université Laval Mémoires et thèses électroniques (1)
- University of Canberra Research Repository - Australia (1)
- University of Michigan (23)
- University of Queensland eSpace - Australia (10)
- University of Southampton, United Kingdom (4)
- University of Washington (4)
- WestminsterResearch - UK (1)
- Worcester Research and Publications - Worcester Research and Publications - UK (1)
Resumo:
North African steppes are subjected to extreme degradation resulting in the reduction of their surface, genetic erosion of resources, and decrease in biodiversity. "Stipa tenacissima" steppes, which constitute one of the most representative vegetation types in the driest areas of the Mediterranean basin, are continuously degrading. With the aim of contributing to a better knowledge of the floristic composition and diagnosing the state of degradation of these steppes, we conducted a phytoecological analysis of 10 "S. tenacissima" sites in Tunisia. Floristic inventory compiled a systematic list of 46 vascular plant species belonging to 43 genera and 26 families. Species richness ranged from 4 to 18 species per 900 m2. Total vegetation cover was moderate and fluctuated between 22.8% and 49.9%. Our results revealed also a decreasing trend in species richness with increasing elevation (ρ = –0.585). Indeed, species richness was negatively correlated with slope (ρ = –0.19) and positively correlated with sand content (ρ = 0.262). Biological types were dominated by chamaephytes; this chamaephytization is due to the phenomenon of aridization and overgrazing. Moreover, the low species cover and the appearance of nonpalatable species highlighted the vulnerability of these steppes to degradation.