TY - JOUR A1 - Neill, Christopher A1 - Chaves, Joaquín E. A1 - Biggs, Trent A1 - Deegan, Linda A. A1 - Elsenbeer, Helmut A1 - Figueiredo, Ricardo O. A1 - Germer, Sonja A1 - Johnson, Mark S. A1 - Lehmann, Johannes A1 - Markewitz, Daniel A1 - Piccolo, Marisa C. T1 - Runoff sources and land cover change in the Amazon an end-member mixing analysis from small watersheds JF - Biogeochemistry N2 - The flowpaths by which water moves from watersheds to streams has important consequences for the runoff dynamics and biogeochemistry of surface waters in the Amazon Basin. The clearing of Amazon forest to cattle pasture has the potential to change runoff sources to streams by shifting runoff to more surficial flow pathways. We applied end-member mixing analysis (EMMA) to 10 small watersheds throughout the Amazon in which solute composition of streamwater and groundwater, overland flow, soil solution, throughfall and rainwater were measured, largely as part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia. We found a range in the extent to which streamwater samples fell within the mixing space determined by potential flowpath end-members, suggesting that some water sources to streams were not sampled. The contribution of overland flow as a source of stream flow was greater in pasture watersheds than in forest watersheds of comparable size. Increases in overland flow contribution to pasture streams ranged in some cases from 0% in forest to 27-28% in pasture and were broadly consistent with results from hydrometric sampling of Amazon forest and pasture watersheds that indicate 17- to 18-fold increase in the overland flow contribution to stream flow in pastures. In forest, overland flow was an important contribution to stream flow (45-57%) in ephemeral streams where flows were dominated by stormflow. Overland flow contribution to stream flow decreased in importance with increasing watershed area, from 21 to 57% in forest and 60-89% in pasture watersheds of less than 10 ha to 0% in forest and 27-28% in pastures in watersheds greater than 100 ha. Soil solution contributions to stream flow were similar across watershed area and groundwater inputs generally increased in proportion to decreases in overland flow. Application of EMMA across multiple watersheds indicated patterns across gradients of stream size and land cover that were consistent with patterns determined by detailed hydrometric sampling. KW - Cattle pasture KW - Deforestation KW - Flowpaths KW - Principal components analysis KW - Overland flow KW - Soil solution Y1 - 2011 U6 - https://doi.org/10.1007/s10533-011-9597-8 SN - 0168-2563 VL - 105 IS - 1-3 SP - 7 EP - 18 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Schulz, Jennifer J. A1 - Cayuela, Luis A1 - Rey-Benayas, Jose M. A1 - Schröder-Esselbach, Boris T1 - Factors influencing vegetation cover change in Mediterranean Central Chile (1975-2008) JF - Applied vegetation science : official organ of the International Association for Vegetation Science N2 - Questions: Which are the factors that influence forest and shrubland loss and regeneration and their underlying drivers? Location: Central Chile, a world biodiversity hotspot. Methods: Using land-cover data from the years 1975, 1985, 1999 and 2008, we fitted classification trees and multiple logistic regression models to account for the relationship between different trajectories of vegetation change and a range of biophysical and socio-economic factors. Results: The variables that most consistently showed significant effects on vegetation change across all time-intervals were slope and distance to primary roads. We found that forest and shrubland loss on one side and regeneration on the other often displayed opposite patterns in relation to the different explanatory variables. Deforestation was positively related to distance to primary roads and to distance within forest edges and was favoured by a low insolation and a low slope. In turn, forest regeneration was negatively related to the distance to primary roads and positively to the distance to the nearest forest patch, insolation and slope. Shrubland loss was positively influenced by slope and distance to cities and primary roads and negatively influenced by distance to rivers. Conversely, shrubland regeneration was negatively related to slope, distance to cities and distance to primary roads and positively related to distance from existing forest patches and distance to rivers. Conclusions: This article reveals how biophysical and socioeconomic factors influence vegetation cover change and the underlying social, political and economical drivers. This assessment provides a basis for management decisions, considering the crucial role of perennial vegetation cover for sustaining biodiversity and ecosystem services. KW - Deforestation KW - Driving forces KW - Forest regeneration KW - Land-cover change KW - Shrubland regeneration Y1 - 2011 U6 - https://doi.org/10.1111/j.1654-109X.2011.01135.x SN - 1402-2001 VL - 14 IS - 4 SP - 571 EP - 582 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Landholm, David M. A1 - Pradhan, Prajal A1 - Kropp, Jürgen T1 - Diverging forest land use dynamics induced by armed conflict across the tropics JF - Global environmental change : human and policy dimensions N2 - Armed conflicts trigger region-specific mechanisms that affect land use change. Deforestation is presented as one of the most common negative environmental impacts resulting from armed conflicts, with relevant consequences in terms of greenhouse gas emissions and loss of ecosystem services. However, the impact of armed conflict on forests is complex and may simultaneously lead to positive and negative environmental outcomes, i.e. forest regrowth and deforestation, in different regions even within a country. We investigate the impact that armed conflict exerted over forest dynamics at different spatial scales in Colombia and for the global tropics during the period 1992–2015. Through the analysis of its internally displaced population (departures) our results suggest that, albeit finding forest regrowth in some municipalities, the Colombian conflict predominantly exerted a negative impact on its forests. A further examination of georeferenced fighting locations in Colombia and across the globe shows that conflict areas were 8 and 4 times more likely to undergo deforestation, respectively, in the following years in relation to average deforestation rates. This study represents a municipality level, long-term spatial analysis of the diverging effects the Colombian conflict exerted over its forest dynamics over two distinct periods of increasing and decreasing conflict intensity. Moreover, it presents the first quantified estimate of conflict's negative impact on forest ecosystems across the globe. The relationship between armed conflict and land use change is of global relevance given the recent increase of armed conflicts across the world and the importance of a possible exacerbation of armed conflicts and migration as climate change impacts increase. KW - Armed conflict KW - Deforestation KW - Internally displaced persons KW - Migration KW - Land use change drivers KW - Colombian conflict Y1 - 2019 U6 - https://doi.org/10.1016/j.gloenvcha.2019.03.006 SN - 0959-3780 SN - 1872-9495 VL - 56 SP - 86 EP - 94 PB - Elsevier CY - Oxford ER -