Biodiversity loss along a gradient of deforestation in Amazonian agricultural landscapes
Decaëns, Thibaud ; Martins, Marlúcia B. ; Feijoo, Alexander ; Oszwald, Johan ; Dolédec, Sylvain ; Mathieu, Jérôme ; Arnaud de Sartre, Xavier ; Bonilla, Diego ; Brown, George G. ; Cuellar Criollo, Yeimmy Andrea ; Dubs, Florence ; Furtado, Ivaneide S. ; Gond, Valérie ; Gordillo, Erika ; Clec'h, Solen Le; Marichal, Raphaël ; Mitja, Danielle ; Souza, Izildinha Miranda de; Praxedes, Catarina ; Rougerie, Rodolphe ; Ruiz, Darío H. ; Otero, Joel Tupac ; Sanabria, Catalina ; Velasquez, Alex ; Zararte, Luz Elena M. ; Lavelle, Patrick - \ 2018
Conservation Biology 32 (2018)6. - ISSN 0888-8892 - p. 1380 - 1391.
biodiversity conservation - biodiversity erosion - Brazil - Colombia - land-use changes - landscape intensification - threshold
Assessing how much management of agricultural landscapes, in addition to protected areas, can offset biodiversity erosion in the tropics is a central issue for conservation that still requires cross-taxonomic and landscape-scale studies. We measured the effects of Amazonia deforestation and subsequent land-use intensification in 6 agricultural areas (landscape scale), where we sampled plants and 4 animal groups (birds, earthworms, fruit flies, and moths). We assessed land-use intensification with a synthetic index based on landscape metrics (total area and relative percentages of land uses, edge density, mean patch density and diversity, and fractal structures at 5 dates from 1990 to 2007). Species richness decreased consistently as agricultural intensification increased despite slight differences in the responses of sampled groups. Globally, in moderately deforested landscapes species richness was relatively stable, and there was a clear threshold in biodiversity loss midway along the intensification gradient, mainly linked to a drop in forest cover and quality. Our results suggest anthropogenic landscapes with high-quality forest covering >40 % of the surface area may prevent biodiversity loss in Amazonia.
Mapping ecosystem services: The supply and demand of flood regulation services in Europe
Sturck, J. ; Poortinga, A. ; Verburg, P.H. - \ 2014
Ecological Indicators 38 (2014). - ISSN 1470-160X - p. 198 - 211.
land-use changes - climate-change - changing climate - runoff - soil - protection - catchments - forests - areas - time
Ecosystem services (ES) feature highly distinctive spatial and temporal patterns of distribution, quantity, and flows. The flow of ecosystem goods and services to beneficiaries plays a decisive role in the valuation of ES and the successful implementation of the ES concept in environmental planning. This is particularly relevant to regulating services where demands emerge often spatially separated from supply. However, spatial patterns of both supply and demand are rarely incorporated in ES assessments on continental scales. In this paper, we present an ES modeling approach with low data demand, fit to be employed in scenario analysis and on multiple scales. We analyze flood regulation services at a European scale by explicitly addressing the spatial distribution of ES demand. A flood regulation supply indicator is developed based on scenario runs with a hydrological model in representative river catchments, incorporating detailed information on land, cover, land use and management. Land use sensitive flood damage estimates in the European Union (EU) are employed to develop a spatial indicator for flood regulation demand. Findings are transferred to the EU territory to create a map of the current supply of flood regulation and the potential supply under conditions of natural vegetation. Regions with a high capacity to provide flood regulation are mainly characterized by large patches of natural vegetation or extensive agriculture. The main factor limiting supply on a continental scale is a low water holding capacity of the soil. Flood regulation demand is highest in central Europe, at the foothills of the Alps and upstream of agglomerations. We were able to identify areas with a high potential capacity to provide flood regulation in conjunction with land use modifications. When combined with spatial patterns of current supply and demand, we could identify priority areas for investments in ES flood regulation supply through conservation and land use planning. We found that only in a fraction of the EU river catchments exhibiting a high demand, significant increases in flood regulation supply are achievable by means of land use modifications. (C) 2013 Elsevier Ltd. All rights reserved.
Lumped surface and sub- surface runoff for erosion modeling within a small hilly watershed in northern Vietnam
Bui, Y.T. ; Orange, D. ; Visser, S.M. ; Hoanh, C.T. ; Laissus, M. ; Poortinga, A. ; Tran, D.T. ; Stroosnijder, L. - \ 2014
Hydrological Processes 28 (2014)6. - ISSN 0885-6087 - p. 2961 - 2974.
land-use changes - soil-erosion - sediment transport - steep slopes - sensitivity-analysis - scale - infiltration - catchments - framework - thailand
Developing models to predict on-site soil erosion and off-site sediment transport at the agricultural watershed scale represent an on-going challenge in research today. This study attempts to simulate the daily discharge and sediment loss using a distributed model that combines surface and sub-surface runoffs in a small hilly watershed (<1km(2)). The semi-quantitative model, Predict and Localize Erosion and Runoff (PLER), integrates the Manning-Strickler equation to simulate runoff and the Griffith University Erosion System Template equation to simulate soil detachment, sediment storage and soil loss based on a map resolution of 30m x 30m and over a daily time interval. By using a basic input data set and only two calibration coefficients based, respectively, on water velocity and soil detachment, the PLER model is easily applicable to different agricultural scenarios. The results indicate appropriate model performance and a high correlation between measured and predicted data with both Nash-Sutcliffe efficiency (Ef) and correlation coefficient (r(2)) having values>0.9. With the simple input data needs, PLER model is a useful tool for daily runoff and soil erosion modeling in small hilly watersheds in humid tropical areas.
Environmental conditions and human drivers for changes to North Ethiopian mountain landscapes over 145 years
Nyssen, J. ; Frankl, A. ; Haile, M. ; Hurni, H. ; Descheemaeker, K.K.E. ; Crummey, D. ; Ritler, A. ; Portner, B. ; Nievergelt, B. ; Moeyersons, J. ; Munro, N. ; Deckers, J. ; Billi, P. ; Poesen, J. - \ 2014
Science of the Total Environment 485-486 (2014). - ISSN 0048-9697 - p. 164 - 179.
land-use changes - tigray highlands - water conservation - cover dynamics - montane forest - soil-erosion - degradation - eucalyptus - rainfall - climate
As quantitative or spatially distributed studies of environmental change over truly long-term periods of more than 100 years are extremely rare, we re-photographed 361 landscapes that appear on historical photographs (1868–1994) within a 40,000 km2 study area in northern Ethiopia. Visible evidence of environmental changes apparent from the paired photographs was analyzed using an expert rating system. The conditions of the woody vegetation, soil and water conservation structures and land management were worse in the earlier periods compared to their present conditions. The cover by indigenous trees is a notable exception: it peaked in the 1930s, declined afterwards and then achieved a second peak in the early 21st century. Particularly in areas with greater population densities, there has been a significant increase in woody vegetation and soil and water conservation structures over the course of the study period. We conclude that except for an apparent upward movement of the upper tree limit, the direct human impacts on the environment are overriding the effects of climate change in the north Ethiopian highlands and that the northern Ethiopian highlands are currently greener than at any other time in the last 145 years.
Assessing the impacts of livestock production on biodiversity in rangeland ecosystems
Alkemade, R. ; Reid, R.S. ; Berg, M. van den; Leeuw, J. de; Jeuken, M. - \ 2013
Proceedings of the National Academy of Sciences of the United States of America 110 (2013)52. - ISSN 0027-8424 - p. 20900 - 20905.
land-use changes - south-africa - diversity - conservation - assemblages - grassland - management - scenarios - responses - savanna
Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss.
Natural and anthropogenic controls on soil erosion in the internal betic Cordillera (southeast Spain)
Bellin, N. ; VanAcker, V. ; Wesemael, B. van; Solé-Benet, A. ; Bakker, M.M. - \ 2011
Catena 87 (2011)2. - ISSN 0341-8162 - p. 190 - 200.
sediment yield variability - land-use changes - check-dams - east spain - se spain - mediterranean areas - northern ethiopia - spatial variation - trap efficiency - runoff
Soil erosion in southeast Spain is a complex process due to strong interactions between biophysical and human components. Significant progress has been achieved in the understanding of soil hydrological behavior, despite the fact that most investigations were focused on the experimental plot scale. Although experimental plots allow exploring the effect of multiple biophysical and anthropogenic factors, they provide limited insights in the combined effect of all factors acting together at the landscape scale. In this study, area-specific sediment yields (SSY) have been estimated based on the volume of sediment trapped behind 36 check dams in the southeast of Spain. Low SSY-values were reported (mean = 1.40 t ha-1 year-1: median = 0.61 t ha-1 year-1). SSY variability could be explained for 67% by catchment characteristics such as drainage area, soil characteristics, land cover, average catchment slope, and annual rainfall. The low SSY values are probably caused by the agricultural abandonment that occurred over the past decades and allowed the recovery of natural vegetation. Furthermore, our results suggest that the soils have eroded in the past to such an extent that nowadays not much sediment is detached by overland flow due to residual enrichment of clay and stones. Also, sediment is to a large extent trapped locally in the catchment, as indicated by the negative relationship between SSY and catchment area
Meso-scale catchment sediment budgets: combining field surveys and modeling in the Dragonja cachtment, southwest Slovenia
Keesstra, S.D. ; Bruijnzeel, L.A. ; Huissteden, J. van - \ 2009
Earth Surface Processes and Landforms 34 (2009)11. - ISSN 0197-9337 - p. 1547 - 1561.
lowland agricultural catchments - step-pool channel - coon creek basin - land-use changes - soil-erosion - floodplain sedimentation - material transport - drainage-basin - river gravel - sw slovenia
In this paper, we present a methodology to construct a sediment budget for meso-scale catchments. We combine extensive field surveys and expert knowledge of the catchment with a sediment delivery model. The meso-scale Mediterranean drainage basin of the Dragonja (91 km2), southwest Slovenia, was chosen as case study area. During the field surveys, sheet wash was observed on sloping agricultural fields during numerous rainfall events, which was found to be the main source of sediment. With the sediment yield model WATEM/SEDEM the estimated net erosion on the hillslopes 4·1 t ha-1 y-1 (91% of inputs). The second source, bank erosion (4·2%; 0·25 t ha-1 y-1) was monitored during several years with erosion pins and photogrammetric techniques. The last source, channel incision, was derived from geomorphological mapping and lichenomery and provided 3·8% (0·17 t ha-1 y-1) of the sediment input. The river transports its suspended sediment mainly during high-flow events (sampled with automated water samplers). About 27% (1·2 t ha-1 y-1) of the sediment delivered to the channel is deposited on floodplains and low terraces downstream (estimated with geomorphological mapping, coring and cesium-137 measurements). The sediment transported as bedload disintegrates during transport to the outlet due to the softness of the bedrock material. As a result, the river carries no bedload when it reaches the sea. The results imply a build-up of sediment in the valleys catchment. However, extreme flood events may flush large amounts of sediment stored in the lower parts of the system. Geomorphological evidence exists in the catchment that such high magnitude, low frequency events have happened in the past
Discharge simulations performed with a hydrological model using bias corrected regional climate model input
Pelt, S.C. van; Kabat, P. ; Maat, H.W. ter; Hurk, B.J.J.M. van den; Weerts, A.H. - \ 2009
Hydrology and Earth System Sciences 13 (2009). - ISSN 1027-5606 - p. 2387 - 2397.
neerslag - afvoer - hydrologie van stroomgebieden - maas - klimaatverandering - modellen - precipitation - discharge - catchment hydrology - river meuse - climatic change - models - land-use changes - extreme floods - runoff - europe - impact - output - flows - basin
Studies have demonstrated that precipitation on Northern Hemisphere mid-latitudes has increased in the last decades and that it is likely that this trend will continue. This will have an influence on discharge of the river Meuse. The use of bias correction methods is important when the effect of precipitation change on river discharge is studied. The objective of this paper is to investigate the effect of using two different bias correction methods on output from a Regional Climate Model (RCM) simulation. In this study a Regional Atmospheric Climate Model (RACMO2) run is used, forced by ECHAM-5 under the condition of the SRES-A1B emission scenario, with a 25 km horizontal resolution. The RACMO2 runs contain a systematic precipitation bias on which two bias correction methods are applied. The first method corrects for the wet day fraction and wet day average (WD bias correction) and the second method corrects for the mean and coefficient of variance (MV bias correction). The WD bias correction initially corrects well for the average, but it appears that too many successive precipitation days were removed with this correction. The second method performed less well on average bias correction, but the temporal precipitation pattern was better. Subsequently, the discharge was calculated by using RACMO2 output as forcing to the HBV-96 hydrological model. A large difference was found between the simulated discharge of the uncorrected RACMO2 run, the WD bias corrected run and the MV bias corrected run. These results show the importance of an appropriate bias correction
Changing sediment dynamics due to natural reforestation in the Dragonja catchment, S.W. Slovenia
Keesstra, S.D. ; Dam, O. van; Verstraeten, G. ; Huissteden, J. van - \ 2009
Catena 78 (2009)1. - ISSN 0341-8162 - p. 60 - 71.
coon creek basin - land-use changes - floodplain sedimentation - agricultural catchments - gully erosion - soil-erosion - river - australia - delivery - storage
Under the influence of socio¿economic changes in many regions in Europe, a trend of decreasing agricultural activity has been observed since the Second World War. The resulting reforestation profoundly changes water and sediment supply to river channels, deposition rates on the floodplains and erosion rates on the hillslopes. We studied these changes in the 91 km2 Dragonja catchment in southwestern Slovenia. With the spatially distributed erosion and sediment delivery model WATEM/SEDEM, the hillslope sediment delivery to the river channel was calculated on the basis of parameters (soil and precipitation parameters, a DEM and land use) measured in the field and laboratory in 2002 and land use maps based on aerial photographs from 1954, 1975, 1985 and 1994. For two independent calibrations WATEM/SEDEM modelled a sharp decline of 69% in total hillslope sediment delivery from 1954 to 2002. As the sub-catchments Rokava and Upper-Dragonja did not reforest in the same way, the sediment yield response is different as well. Separate calculations show the same reduction (45%) in sediment yield from 1954 to 1975. After 1975 the sediment yield was stable in the Rokava sub-catchment. In the Upper-Dragonja the trend continued, to a total reduction of 76% of sediment outflow since 1954. The sources of fine sediment were determined by analysing the hysteresis of the discharge waves, and the suspended sediment texture. The sediment that leaves the catchment originates from three sources: hillslopes, erosional bedrock banks and sedimentary riverbanks. The analysis of the suspended sediment texture suggests that during a discharge wave the suspended sediment originates predominantly from the hillslopes. During low stage the sparse sediment in the water column largely originates from large bedrock banks. The sedimentary riverbanks are not an important source of suspended sediment
Impact of natural reforestation on floodpain sedimentation in the Dragonja basin, SW Slovenia
Keesstra, S.D. - \ 2007
Earth Surface Processes and Landforms 32 (2007)1. - ISSN 0197-9337 - p. 49 - 65.
land-use changes - fluvial processes - soil properties - river - erosion - cesium-137 - catchment - reafforestation - subsequent - vegetation
Changes in floodplain sediment dynamics have profound effects on riverine habitats and riparian biodiversity. Depopulation due to socio-economic changes in the Dragonja catchment (91 km2) in southwestern Slovenia resulted in the abandonment of agricultural fields, followed by natural reforestation since 1945. This profoundly changed the water and sediment supply to the streams, as well as floodplain sediment deposition. This paper presents a reconstruction of the development of the Dragonja floodplain due to these land use changes during the last 60 years. The reconstruction is based on dating of floodplain sediments using 137Cs profiles, measurement of actual sedimentation rates using artificial grass sedimentation mats, and linking this information to the present-day hydrological behaviour of the river. The sedimentation mats showed that floodplain sedimentation was restricted to peak flows of considerable magnitude. Due to the reforestation, the return period of such high flows increased from 0·31 year in the period 1960-1985 to 0·81 year between 1986 and 2003, with commensurate changes in sedimentation rates. At the 1·5 m river terrace (formed about 60 years ago), 137Cs-based sedimentation rates (1960-1986) were roughly twice the rates inferred from the artificial grass mats (2001-2003). This finding matches the increase in the return period for larger peak events during the 1986-2003 period, which caused fewer major inundations at this level. Conversely, sedimentation rates determined for the lowest terrace at 0·5 m were similar for both techniques (and periods) because the return periods of the peak events responsible for sediment deposition at this lower level did not change much over the period 1986-2003.