Environmental changes in biodiversity hotspot ecosystems of
South Ecuador: RESPonse and feedback effECTs (FOR2730)

Abstract:

Future climate and land use change may have a great impact on essential ecosystem functions such as carbon storage and water supply of the Andean p´aramo ecosystem. As hydrogeochemical processes in the p´aramo and possible reactions to these changes are still largely unknown, nutrient fluxes during storm flow events in a p´aramo catchment in the Cajas National Park of south Ecuador were studied. From February to June 2014, discharge and stream concentrations of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity and nitrate (NO3-N) were monitored in five minute intervals in the Quinuas River. In order to study the catchment’s response to rainfall events, rotational patterns of concentration-discharge hysteresis effects were analysed. In total, 35 events were suitable for analysing hysteresis effects of BOD, COD, and turbidity. Nitrate concentrations were studied in 20 events. Precipitation events led to an increase of concentration of all parameters. Hysteresis patterns showed a high consistency. COD, turbidity, and nitrate rotated mainly clockwise, BOD counterclockwise. Therefore, a fast response of the sources of COD, nitrate, and turbidity is suggested. This might be mainly due to a fast subsurface flow through the upper organic soil horizons. BOD sources, mainly soil surface and litter layer, predominate later in the storm flow event

Abstract:

Conflicts between satisfying the growing global demand for food and energy and simultaneously preserving natural ecosystems have spurred renewed debate about how to optimise future land use. This study reviews the role of forests and forest management within these proposed land-use strategies and reveals that discussions about future management of forest and agricultural lands take place largely exclusive of one another. Based on these results, a land-use concept is proposed in which sustainable agricultural intensification is paired with land-use diversification as a risk reduction strategy and complemented by productive restoration and compensation payments for forest conservation. Improving afforestation and agroforestry practices on degraded lands and investigating effects of diversification on the landscape scale are identified as important objectives for future interdisciplinary research. Considering forests as part of a comprehensive land-use portfolio will be vital in order to help strengthen links and ease conflicts between forest and agricultural land uses.

Abstract:

Analyses were carried out on financial compensation to avoid loss of tropical forests and related carbon (C) emissions when marginal financial yield declined for land-use options with extended areas, and when a riskaverting perspective (modeled according to financial theory around the capital asset pricing model) is assumed. The approach in this study was to consider natural forest, forest plantation, pasture, and cropland simultaneously to investigate how an optimized land-use distribution may reduce the amount of compensation necessary to avoid C emissions from forest loss. The financial compensations derived were as high as US$ 176 per hectare per year when comparing natural forests only with the most profitable alternative (croplands). However, compensation decreased to US$ 124 for risk-neutral decision-makers, who would strive for optimized land-use allocation, and to only US$ 47 per hectare per year for risk-avoiders, who would look to maximize the reward-to-variability ratio. Sensitivity analyses indicated that the compensation under risk-aversion increased much less than under risk-ignoring when increased productivity of agricultural land-use or growing demand for agricultural products was simulated. It was concluded that considering appropriate diversification strategies and the well documented human behavior to avoid risks is an important step in developing cost-effective compensation policies.