Aim: Introduction of a novel approach to the classification of vegetation data (species by plot matrices). This approach copes with a large amount of noise, groups irregularly shaped in attribute space and species turnover within groups. Method: The proposed algorithm (Isopam) is based on the classification of ordination scores from isometric feature mapping. Ordination and classification are repeated in a search for either high overall fidelity of species to groups of sites, or high quantity and quality of indicator species for groups of sites. The classification is performed either as a hierarchical, divisive method or as non-hierarchical partitioning. In divisive clustering, resulting groups are subdivided until a stopping criterion is met. Isopam was tested on 20 real-world data sets. The resulting classifications were compared with solutions from eight widely used clustering algorithms. Results: When looking at the significance of species fidelities to groups of sites, and at quantity and quality of indicator species, Isopam often achieved high ranks as compared with other algorithms.
In many developing tropical regions, especially indigenous people are often deprived of their traditional land use rights due to the establishment of protected areas. This conservation practice jeopardizes people's livelihoods and ultimately counteracts conservation efforts by provoking illegal use of natural resources. Thus, approaches that consider local livelihood needs in conservation planning are of high importance. In this regard, methods to quantify human impact on conservation-relevant biodiversity features, e.g., species richness, are required to objectively evaluate the effectiveness of current management practices and to facilitate tradeoffs between land use and nature conservation. We introduce an approach that draws on the degree of human-induced forest fragmentation as a proxy for land use intensity. Quantitative information on forest fragmentation was obtained by applying landscape metrics on satellite imagery. We analyzed relations between this proxy and vascular plant species data from an Indian protected area. In our case, species richness on a local scale was only marginally affected by forest fragmentation. However, ongoing land use throughout the reserve resulted in distinct alterations of species composition and promotion of biological invasion.Zusammenfassung: Die Einrichtung von Schutzgebieten führt in tropischen Entwicklungsregionen oft zu Spannungen, da vielerorts traditionelle Landnutzungsformen eingeschränkt werden. Strenge Schutzauflagen entziehen nicht nur der indigenen Bevölkerung die Lebensgrundlage, sondern wirken auch dem eigentlichen Schutzgedanken entgegen, da sie eine illegale und damit unkontrollierte Nutzung der natürlichen Ressourcen herausfordern. Zur Entwicklung von alternativen Schutzkonzepten werden Methoden benötigt, die objektiv den menschlichen Einfluss auf schutzwürdige Aspekte der Biodiversität erfassen. In der vorliegenden Studie wird am Beispiel eines indischen Schutzgebietes ein derartiger Ansatz vorgestellt, der über die als Indikator verwendete anthropogen hervorgerufene Waldfragmentierung Rückschlüsse auf die Auswirkungen der tatsächlich vorliegenden Landnutzungsintensität erlaubt. Der Grad der Fragmentierung wurde quantitativ aus einem Satellitenbild bestimmt und in Bezug zu flächenbezogenen Aspekten der Biodiversität (Artenreichtum, Artenzusammensetzung und Auftreten invasiver Arten) gesetzt. Während sich der Artenreichtum entlang des Fragmentierungsgradienten kaum änderte, wurden mit steigender Fragmentierung deutliche Änderungen der Artenzusammensetzung sowie ein zunehmendes Auftreten invasiver Arten beobachtet.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.