28.2.2017: Forschung international
Neuste Forschung zu Lebensraum-Fragmentierung
Dernières connaissances sur la fragmentation des habitats
Lebensraumfragmentierung ist eine der dominantesten Ursachen des anthropogen verursachten globalen Wandels. Sie beeinflusst Ökosysteme von der genetischen Struktur von Populationen bis zur Biodiversität in einer Region. Die Konsequenzen der Lebensraumfragmentierung zu verstehen und zu wissen, wie diese vermindert werden können, ist deshalb von ausserordentlicher Bedeutung. Eine open-access Spezialausgabe der Zeitschrift Ecography fasst den aktuellen Stand der Forschung zusammen. Besonderes Gewicht wird dabei auf die Ergebnisse von Langzeitexperimenten und der Entwicklung von Theorien zur Habitatfragmentierung gelegt.
La fragmentation de l'habitat est l'une des causes dominantes du changement global. Elle influence les écosystèmes depuis la structure génétique des populations jusqu’à la biodiversité d'une région. Comprendre les conséquences de la fragmentation des habitats et connaître la façon dont elle peut être réduite revêt une importance considérable pour la conservation de la nature. Un numéro spécial open-access du journal Ecography (janvier 2017, 40/1) résume l’état actuel de la recherche. Un accent particulier est placé sur les résultats des expériences de longue durée et sur le développement des théories sur la fragmentation de l'habitat.
The Special Issue draws together: 1) experiments that are now mature, up to several decades old, permitting evaluations of the effects of fragmentation on different dimensions of biological responses, including lengthy time lags in responses; 2) a proliferation of theories that can be synthesized and evaluated against experimental data, permitting a new round of fresh theory synthesis; and 3) a new understanding of applications of the science of fragmentation to conservation.
The Special Issue features 12 new publications from authors and experiments that span the globe and span decades, including research on church forests in Africa, wild bee populations in France and Australia, and tree communities in central Amazonia. Key highlights from the articles include:
• There is little experimental evidence to support the habitat amount hypothesis, which suggests that sample area effect overrides patch size and patch isolation effects of habitat fragmentation on species richness.
• Sacred natural sites, such as the church forests across northern Ethiopia, may act a useful middle ground between experimental and observational studies of fragmentation.
• The interplay of ecology and evolution modulates processes and interactions in fragmented landscapes, and there still exists a large gap between theory and experiment.
• It is unlikely that fragmented tropical landscapes with limited human disturbance will revert back to early or mid-succesional states in the future, since future composition is strongly dependent on present-day composition.
• Regardless of whether a fragmented landscape has strongly or weakly defined structural edges, conceptual models that view the landscape as a simple patch-matrix are less effective than models that view it as an ecological continuum or as a hybrid of continuum and patch-matrix models.
• A new framework allows for species and community-level predictions for the change and loss of biodiversity under global change by comparing the processes behind species-area relationships (SAR), metapopulation models (MEP), and species distribution models (SDM).
• Habitat fragmentation has had a significant impact on the evolution of dispersal strategies and dispersal syndromes, affecting our ability to predict and manage populations in fragmented landscapes.
• The loss of habitat and connectivity in metacommunity networks leads to lower species diversity, loss of ecosystem function, and less stability by eroding the “spatial insurance” that ecosystems enjoy.
• A survey of conservation practitioners shows that landscape connectivity and patch area are highly valued, but there is an information gap between what is learned from studies of habitat fragmentation and factors central to the practice of biodiversity conservation.
• Plant community composition responds differently to fragmentation over time based on changes to the matrix and how the habitat became fragmented in the first place.
• The distribution of ecological traits in bees shifts along a gradient of habitat amount and habitat fragmentation, indirectly affecting ecosystem services such as crop pollination.
• New methods to determine thresholds for habitat loss provide more realistic models and suggest that the maximum permissible habitat loss threshold is 40%.
Quelle: Conservation Corridor
Keywords:
Fragmentierung, Lebensraum, Habitat, Landschaft, Auswirkungen
Art der Publikation:
Fachpublikation
Literatur:
Ecography Special Issue: Fragmentation Special Issue, January 2017, Volume 40, Issue 1, Pages 1237
http://conservationcorridor.org/2017/01/ecography-special-issue-highlights-latest-research-on-habitat-fragmentation/
http://onlinelibrary.wiley.com/doi/10.1111/ecog.2017.v40.i1/issuetoc/
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