Browsing by Subject "Naturkautschuk"

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Conflicts of human land-use and conservation areas : the case of Asian elephants in rubber-dominated landscapes of Southeast Asia
(2017) Harich, Franziska K.; Treydte, Anna C.
Over the last decades, expanding rubber plantations in Southeast Asia have continuously diminished natural habitat, thereby increasing conflicts between human land-uses and nature conservation. The consequences are manifold, with short-term economic benefits for smallholder farmers and long-term costs for species diversity and ecosystem services (ESS). Sustainable wildlife populations are critical for ecosystem functioning but the ongoing habitat degradation and conflicts with people threaten the survival of larger mammal populations. This trend is particularly problematic if the respective species in decline are keystone species such as the Asian elephant (Elephas maximus), which holds important ecological functions in maintaining tree diversity. Continuous land-use transformations increase the importance of conservation efforts for biodiversity within the agricultural matrix. The major aim of this thesis’ work was to analyze the potential of rubber-dominated landscapes in sustaining wild mammal populations while considering the risk of conflicts due to wildlife damage as well as the ecological importance of mammals. As a first step, the literature on wild mammals in rubber and oil palm plantations was analyzed to provide an overview on species diversity found in these systems. Our review showed that species richness was highly reduced in the plantations compared to the forest and that most species in the farms were rather visitors than residents. For a detailed assessment of species richness and presence in rubber plantations, transect and camera trap surveys were conducted in the farm-forest transition zone of the Tai Rom Yen National Park in southern Thailand. Furthermore, farmers were interviewed on the kind and extent of wildlife damage. With 35 recorded wildlife species, the forest was found to hold the highest diversity while more than 70% of these mammals were still found at the forest edge. However, a strong decline of species diversity and presence was observed in the farmland. Crop damage by wildlife affected 40% of all interviewed farmers. In 85% of all rubber damage incidents, young trees were affected, which had not yet been tapped. Elephants were most frequently named as damage causing species. Nevertheless, damage to rubber occurred only in half of the elephant visits, indicating that this crop species was not particularly attractive to wildlife. To account not only for the costs inflicted through elephant damage but also for the ecological benefits elephants provide, the potential of these megaherbivores for seed dispersal was assessed as a crucial ecological function in forest ecosystems. Feeding experiments with elephants were conducted and germination success of ingested and fresh control seeds of a tree species with characteristic mega-faunal syndrome fruits (Dillenia indica L.) was monitored. Seeds ingested by elephants showed a significantly higher and earlier likelihood for germination compared to control seeds. The exemplary tree species in our experiments did not solely depend on but benefited from elephant consumption for germination. This highlights the risks of long-term negative implications for certain tree species and entire ecosystems if elephant and other large mammal populations further decline. Biodiversity is an integral component of ecosystem functioning and the provisioning of services. However, a challenge in the evaluation of ESS is the allowance for the many facets of biodiversity assessments. We therefore developed a methodology for including multiple levels of species diversity into an ESS evaluation model. Diversity data of animal groups and plants derived from our data collections and from literature were normalized using the most diverse habitat as benchmark. Through this approach we obtained a comparable habitat suitability matrix for different land-use systems, which was then applied to different land-use scenarios. The outcomes confirmed that a conservation focused scenario scored higher habitat suitability for all species as well as for threatened ones compared to two other scenarios with no or limited conservation measures. Increasing conflicts between human land-use and nature conservation as a result of shrinking resources pose imminent risks for the diversity and resilience of ecosystems. This thesis provides an assessment of the current state of and conflicts with wildlife diversity in rubber-dominated landscapes surrounding protected areas. The results of this thesis can serve as a basis for the development of measures to consolidate farming and conservation interests. Although intensively managed plantations cannot substitute for natural forests, efforts are required to conserve multiple levels of biodiversity within the farming landscape. High species diversity will maintain ecosystem functions and services sustainably, which both human and wildlife communities rely on for their long-term persistence.