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In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434–484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions. peerReviewed

Tropical montane cloud forests (TMCFs) are differentiated from other forest types by their frequent immersion in fog. This characteristic implies that TMCFs are unique in their hydrological functioning, as they receive a substantial amount of water input via direct deposition of cloud droplets. Because it is generally associated with reduced solar radiation and increased humidity, frequent fog occurrence can lower evapotranspiration (ET). Many TMCFs also have certain characteristic structural and floristic features, which have further hydrological effects. Cloud water is often chemically different from rain water (Heath 2001; Liang et al. 2009); hence, fog deposition can alter inputs of nutrients and other chemicals into the ecosystem. The hydrological, biological, and chemical characteristics of cloud forests give rise to differences in biogeochemical processes as well.

Indonesia’s annual deforestation rate of –1.2% is dramatic compared for example to Brazil’s 0.4% loss of forest cover. Sulawesi region of Indonesia still has a forest cover of 48%, but as population has been growing by 66% over the past 2 decades, massive land cover transformations are going on that have changed the land cover pattern and consequently soil and water resources of the region are altering as well. Since 2001, we investigate the impact of forest conversion on the water balance, nutrient losses and soil erosion of a small mesoscalic tropical catchment, which is integrated into the long-term interdisciplinary collaborative project STORMA (http://www.storma.de). The study was conducted in a small mountainous catchment, which is located at the north-eastern border of the Lore Lindu National Park Central of Sulawesi. The Nopu catchment (51S 01757231E, 9867683 N) covers an area of approximately 2.6 km2. Since 2001 the catchment is monitored with three weirs (automatic stage recorder), one climate station and six rain gauges. Traditional slash & burn cultivation is predominant and heavy machinery is not used. At two sub-catchments (rainforest weir 3, slash & burn weir 2) changes in river discharge and nutrient outputs with time and differences were analysed since 2002. As indicators for land degradation we studied the changes of infiltration rate, water flow path (increasing interflow and surface flow) and soil nutrient output with river discharge. In the Nopu catchment slash & burn activities increased mainly since 2003/2004 with forest reduction until 2007 in the sub-catchment weir 2 from 87% (2001) to 26% forest cover (2007). Due to forest conversion, river discharge increased from 9 to 17% for the period 2002/2003–2005/2006 mainly driven by increase in overland flow and quick interflow. Three scenarios (forest/cacao/slash & burn (corn with cassava)) were simulated with the application of the water balance model WASIM-ETH. Simulation results supported the experimental results showing an increase from 8% to 17% annual discharge for cacao and slash & burn scenario and give insight into the changing discharge components. The increase in overland flow leads to an increase in soil erosion with doubling of suspended sediment output from 2003 to 2005. Also, higher soil nutrient leaching and increase in quick interflow has caused an increase by ratios of 1.5–1.9 of the main cations (Ca, Mg, K) and nitrogen (TNb) in the sub-catchment partially deforested compared to the natural forest sub-catchment. After 2005/2006, land degradation indicators of suspended sediment output and soluted nutrient output indicate a “stabilizing effect” with decrease due to land use change to cacao agroforestry in the mid slopes of the catchment.

Six areas developed on metamorphic and igneous parent materials were selected in Murcia Province (SE Spain), two from diabases, two from mica schist and two from andesites. Three of them potentially polluted by anthropogenic sources and the other three no polluted. One profile and 6 surface samples were collected from each one in order to identify the Pb and Zn concentrations bounded to different soil phases using sequential extraction and to verify if the existent differences in Pb and Zn concentrations from soils developed on the same parent material are the consequence of the anthropogenic activities, or natural geochemical contributions. The results showed that the soils that present higher total Pb and Zn concentrations that come from anthropogenic sources registered higher percentages of these heavy metals in the most labile phases (exchangeable and organic matter bounded heavy metals). In addition, the carbonate phase is also an important sink of metals, however in soils developed on metamorphic and igneous rocks this constituent is very low due to organic and exchangeable phases that retain these metals. This behaviour increases the risk of mobility to trophic chain to plants and microorganisms that may absorb these metals.