Elevational patterns in tree diversity of tropical montane rain forests with different soil nutrient conditions in Sulawesi, Indonesia
Final Report Abstract
We studied elevational patterns in tree diversity, species composition, functional traits, and aboveground biomass (AGB) of old-growth tropical montane rain forests with different soil nutrient conditions in Sulawesi, Indonesia. Data were collected from an elevational transect of 13 sites spanning 1700 m (c. 700 – 2400 m a.s.l.) in Lore Lindu National Park, one of the largest remaining contiguous blocks of forest remaining in Sulawesi. The original sampling design, including a soil-nutrient gradient, had to be modified due to time constraints and lack of suitable research sites: The extent of nutrient-rich areas on volcanic substrate was smaller than expected and human activities have led to a rapid decrease of forest cover in recent years. A total of 3848 trees were inventoried and we collected over 2000 botanical specimens as well as numerous samples of leaves, wood, mycorrhiza and soil. More than half of the plants have been identified, so far yielding three undescribed species and numerous new records for Sulawesi. Analysis of functional traits, tree growth and soil properties is on the way. Diversity of tree taxa (families) decreased significantly with elevation while variation among sites was high indicating that other environmental factors further shape diversity patterns. Tree community composition changed markedly along the elevation gradient with various tropical families dominant at lower and mid-elevations and conifers dominating the upper-montane belt. Members of the Fagaceae were (co-)dominant at most elevations and Lauraceae and Myrtaceae also represented prominent elements of the forest. Basal area was invariable across elevations reflecting opposite trends in the number of trees (increasing with elevation) and tree size (decreasing with elevation). A meta-analysis of the elevational change in the taxonomic and phylogenetic diversity of tree assemblages in different biogeographical subregions of Malesia points to ecological, evolutionary and biogeographic processes (environmental filtering, sympatry, and long-distance dispersal) as shaping factors of the contemporary community structure of Malesian mountain forests. Wallace’s Line does not represent a significant barrier between the tree floras of Borneo and Sulawesi at higher elevations. The uniqueness of high-elevation forests in terms of their high phylogenetic diversity and unique structure calls for a high priority in conservation programs.
Publications
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(2013): Elevational patterns in the diversity of plant groups in mountain rain forests of Central Sulawesi, Indonesia. Poster presented at the 2nd Southeast Asian Gateway Evolution Meeting (SAGE 2013), 11.-15.03.2013 in Berlin, Germany
Brambach, F., Mangopo, H., Leuschner, C. & Culmsee, H.
