scholarly journals Influence of Late Holocene Climate Change and Human Land Use on Terrestrial and Aquatic Ecosystems in Southwest Madagascar

2021 ◽  
Vol 9 ◽  
Author(s):  
Alejandra I. Domic ◽  
Sean W. Hixon ◽  
Maria I. Velez ◽  
Sarah J. Ivory ◽  
Kristina G. Douglass ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Aquatic Ecosystems ◽  
Late Holocene ◽  
Freshwater Ecosystems ◽  
Dry Forest ◽  
Ecosystem Change ◽  
Human Land Use ◽  
Pastoral Communities ◽  
The Impact

Madagascar’s biota underwent substantial change following human colonization of the island in the Late Holocene. The timing of human arrival and its role in the extinction of megafauna have received considerable attention. However, the impacts of human activities on regional ecosystems remain poorly studied. Here, we focus on reconstructing changes in the composition of terrestrial and aquatic ecosystems to evaluate the impact of human land use and climate variability. We conducted a paleoenvironmental study, using a sediment record that spans the last ∼1,145 years, collected from a lakebed in the Namonte Basin of southwest Madagascar. We examined physical (X-ray fluorescence and stratigraphy) and biotic indicators (pollen, diatoms and micro- and macro-charcoal particles) to infer terrestrial and aquatic ecosystem change. The fossil pollen data indicate that composition of grasslands and dry deciduous forest in the region remained relatively stable during an arid event associated with northward displacement of the Intertropical Convergence Zone (ITCZ) between ∼1,145 and 555 calibrated calendar years before present (cal yr BP). Charcoal particles indicate that widespread fires occurred in the region, resulting from a combination of climate drivers and human agency during the entire span covered by the paleorecord. Following settlement by pastoral communities and the disappearance of endemic megafauna ∼1,000 cal yr BP, grasslands expanded and the abundance of trees that rely on large animals for seed dispersal gradually declined. A reduction in the abundance of pollen taxa characteristic of dry forest coincided with an abrupt increase in charcoal particles between ∼230 and 35 cal yr BP, when agro-pastoral communities immigrated into the region. Deforestation and soil erosion, indicated by a relatively rapid sedimentation rate and high K/Zr and Fe/Zr, intensified between 180 and 70 cal yr BP and caused a consequent increase in lake turbidity, resulting in more rapid turnover of the aquatic diatom community. Land use and ongoing climate change have continued to transform local terrestrial and freshwater ecosystems during the last ∼70 years. The current composition of terrestrial and aquatic ecosystems reflects the legacy of extinction of native biota, invasion of exotic species, and diminished use of traditional land management practices.

scholarly journals The impact of land use and climate change on late Holocene and future suspended sediment yield of the Meuse catchment

Geomorphology ◽  
2009 ◽  
Vol 103 (3) ◽  
pp. 389-400 ◽  
Author(s):  
Philip J. Ward ◽  
Ronald T. van Balen ◽  
Gert Verstraeten ◽  
Hans Renssen ◽  
Jef Vandenberghe
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Suspended Sediment ◽  
Sediment Yield ◽  
Late Holocene ◽  
Suspended Sediment Yield ◽  
The Impact

scholarly journals Parasite transmission in aquatic ecosystems under climate change: joint effects of temperature, host behavior and elimination of parasite larvae by predators

2019 ◽  
Author(s):  
M. Gopko ◽  
E. Mironova ◽  
A. Pasternak ◽  
V. Mikheev ◽  
J. Taskinen
Keyword(s):  
Climate Change ◽  
Aquatic Ecosystems ◽  
Disease Risk ◽  
Freshwater Ecosystems ◽  
Fish Host ◽  
Parasitic Infections ◽  
List Type ◽  
Filter Feeding ◽  
Increased Risk ◽  
The Impact

AbstractA moderate raise in temperature was suggested to enhance the impact of parasites on aquatic ecosystems. Under higher temperatures, poikilothermic animals (e.g. fish), increase their activity, which can result in a more frequent encounter with parasites. However, temperature increase may also trigger processes counteracting an increased risk of parasitic infections. For instance, removal of free-living stages of parasites by filter-feeding organisms can increase with temperature and potentially mitigate disease risk in ecosystems under climate change.In our study, we aimed to find out whether an increased infection transmission under higher temperatures can be, at least, partly compensated by the increased removal of parasitic larvae be aquatic predators. In addition, we planned to reveal the behavioral mechanism underlying the more successful transmission of the parasite at higher temperatures.We experimentally studied how temperature, the behavior of fish host (rainbow trout) and the presence of filter-feeding mussels in the environment influence transmission success of trematode larvae (Diplostomum pseudospathaceum cercariae) to fish host.We found that temperature raise increased, while presence of filter-feeding mussels in the environment decreased infection intensities in fish. However, the effect of mussel’s presence was constant within the tested range of water temperatures (15-23ºC), which suggests that it cannot compensate for the observed increased transmission of parasites under temperature raise. The difference in fish individual behavior (swimming activity) before the exposure to parasites was a substantial factor the affecting host’s vulnerability to infection. However, fish motor activity only weakly correlated with temperature, therefore, it is unlikely to be responsible for the increased infection success under warmer conditions. After exposure to parasites, fish strongly decreased their activity. This decrease was temperature-dependent and more pronounced in bolder (more active) fish, which leads to lower variability in activity of fish exposed to parasites compared with the safe environment. Post-exposure activity did not influence the infection intensity.In general, we showed that the elimination of trematode larvae by filter-feeders is unlikely to deter the potential effects of global warming on host-parasite interactions in temperate freshwater ecosystems.

scholarly journals Sensitivity of Holocene atmospheric CO<sub>2</sub> and the modern carbon budget to early human land use: analyses with a process-based model

2011 ◽  
Vol 8 (1) ◽  
pp. 69-88 ◽  
Author(s):  
B. D. Stocker ◽  
K. Strassmann ◽  
F. Joos
Keyword(s):  
Land Use ◽  
Late Holocene ◽  
Carbon Sink ◽  
Ice Cores ◽  
Atmospheric Co2 ◽  
Terrestrial Carbon ◽  
Dynamic Global Vegetation Model ◽  
Human Land Use ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. A Dynamic Global Vegetation model coupled to a simplified Earth system model is used to simulate the impact of anthropogenic land cover changes (ALCC) on Holocene atmospheric CO2 and the contemporary carbon cycle. The model results suggest that early agricultural activities cannot explain the mid to late Holocene CO2 rise of 20 ppm measured on ice cores and that proposed upward revisions of Holocene ALCC imply a smaller contemporary terrestrial carbon sink. A set of illustrative scenarios is applied to test the robustness of these conclusions and to address the large discrepancies between published ALCC reconstructions. Simulated changes in atmospheric CO2 due to ALCC are less than 1 ppm before 1000 AD and 30 ppm at 2004 AD when the HYDE 3.1 ALCC reconstruction is prescribed for the past 12 000 years. Cumulative emissions of 69 GtC at 1850 and 233 GtC at 2004 AD are comparable to earlier estimates. CO2 changes due to ALCC exceed the simulated natural interannual variability only after 1000 AD. To consider evidence that land area used per person was higher before than during early industrialisation, agricultural areas from HYDE 3.1 were increased by a factor of two prior to 1700 AD (scenario H2). For the H2 scenario, the contemporary terrestrial carbon sink required to close the atmospheric CO2 budget is reduced by 0.5 GtC yr−1. Simulated CO2 remains small even in scenarios where average land use per person is increased beyond the range of published estimates. Even extreme assumptions for preindustrial land conversion and high per-capita land use do not result in simulated CO2 emissions that are sufficient to explain the magnitude and the timing of the late Holocene CO2 increase.

scholarly journals Sensitivity of Holocene atmospheric CO<sub>2</sub> and the modern carbon budget to early human land use: analyses with a process-based model

2010 ◽  
Vol 7 (1) ◽  
pp. 921-952 ◽  
Author(s):  
B. Stocker ◽  
K. Strassmann ◽  
F. Joos
Keyword(s):  
Land Use ◽  
Late Holocene ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Ice Age ◽  
Terrestrial Carbon ◽  
Dynamic Global Vegetation Model ◽  
Human Land Use ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. A Dynamic Global Vegetation model is used as part of a simplified Earth system model to simulate the impact of human land use on Holocene atmospheric CO2 and the contemporary carbon cycle. We show that suggested upward revisions of Holocene land use reconstructions imply a smaller contemporary terrestrial carbon sink and that early agricultural activities did only marginally contribute to the late Holocene CO2 rise of 20 ppm measured on ice cores. Scenarios are used to test the robustness of the results. Simulated changes in atmospheric CO2 due to land use are less than 1 ppm before 0 AD and 22 ppm by 2004 AD when prescribing the HYDE 3.1 land use reconstruction over the past 12 000 years. Cumulative emissions are with 50 GtC by 1850 and 177 GtC by 2004 AD comparable to earlier estimates. In scenario H2, agricultural area from HYDE 3.1 is scaled by a factor of two before 1700 AD, thereby taking into account evidence that land area used per person was higher before than during early industrialisation. Then, the contemporary terrestrial carbon sink, required to close the atmospheric CO2 budget, is reduced by 0.5 GtC yr−1. CO2 changes due to land use change exceed natural interannual variability only after 1000 AD and are less than 4 ppmv until 1850 AD. Simulated CO2 change remains small even in scenarios where average land use per person is unrealistically increased by a factor of 4 to 8 above published estimates. Our results falsify the hypothesis that humans are responsible for the late Holocene CO2 increase and that anthropogenic land use prevented a new ice age.

scholarly journals Dynamics of soil organic carbon in the steppes of Russia and Kazakhstan under past and future climate and land use

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Susanne Rolinski ◽  
Alexander V. Prishchepov ◽  
Georg Guggenberger ◽  
Norbert Bischoff ◽  
Irina Kurganova ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Organic Carbon ◽  
Arable Land ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Scenarios ◽  
The Impact

AbstractChanges in land use and climate are the main drivers of change in soil organic matter contents. We investigated the impact of the largest policy-induced land conversion to arable land, the Virgin Lands Campaign (VLC), from 1954 to 1963, of the massive cropland abandonment after 1990 and of climate change on soil organic carbon (SOC) stocks in steppes of Russia and Kazakhstan. We simulated carbon budgets from the pre-VLC period (1900) until 2100 using a dynamic vegetation model to assess the impacts of observed land-use change as well as future climate and land-use change scenarios. The simulations suggest for the entire VLC region (266 million hectares) that the historic cropland expansion resulted in emissions of 1.6⋅ 1015 g (= 1.6 Pg) carbon between 1950 and 1965 compared to 0.6 Pg in a scenario without the expansion. From 1990 to 2100, climate change alone is projected to cause emissions of about 1.8 (± 1.1) Pg carbon. Hypothetical recultivation of the cropland that has been abandoned after the fall of the Soviet Union until 2050 may cause emissions of 3.5 (± 0.9) Pg carbon until 2100, whereas the abandonment of all cropland until 2050 would lead to sequestration of 1.8 (± 1.2) Pg carbon. For the climate scenarios based on SRES (Special Report on Emission Scenarios) emission pathways, SOC declined only moderately for constant land use but substantially with further cropland expansion. The variation of SOC in response to the climate scenarios was smaller than that in response to the land-use scenarios. This suggests that the effects of land-use change on SOC dynamics may become as relevant as those of future climate change in the Eurasian steppes.

scholarly journals Simulating the Impact of Future Land Use and Climate Change on Soil Erosion and Deposition in the Mae Nam Nan Sub-Catchment, Thailand

2013 ◽  
Vol 5 (8) ◽  
pp. 3244-3274 ◽  
Author(s):  
Pheerawat Plangoen ◽  
Mukand Babel ◽  
Roberto Clemente ◽  
Sangam Shrestha ◽  
Nitin Tripathi
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Erosion And Deposition ◽  
The Impact

scholarly journals Investigation of Climate and Land Use Change Impacts on Stream Flow of Guder Catchment, Ethiopia

2021 ◽  
Author(s):  
Bekam Bekele Gulti ◽  
Boja Mokonnen Manyazew ◽  
Abdulkerim Bedewi Serur
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Stream Flow ◽  
Open Space ◽  
Smart Growth ◽  
Assessment Model ◽  
Study Region ◽  
Climate Conditions ◽  
Change Impact ◽  
The Impact

Abstract Climate change (CC) and land use/cover change (LUCC) are the main drivers of streamflow change. In this paper, we investigate the impact of climate and LULC change impact on stream flow of Guder catchment by using Soil and Water Assessment model (SWAT). The scenarios were designed in a way that LULC was changed while climate conditions remain constant; LULC was then held constant under a changing climate and combined effect of both. The result shows that, the combined impacts of climate change and LULC dynamics can be rather different from the effects that follow-on from LULC or climate change alone. Streamflow would be more sensitive to climate change than to the LULC changes scenario, even though changes in LULC have far-reaching influences on streamflow in the study region. A comprehensive strategy of low impact developments, smart growth, and open space is critical to handle future changes to streamflow systems.

scholarly journals Assessing the Impact of Floods Disaster on Soil Erosion Risk Based on the RUSLE-GloSEM Approach in Western Iran

2021 ◽  
Author(s):  
Morteza Akbari ◽  
Ehsan Neamatollahi ◽  
Hadi Memarian ◽  
Mohammad Alizadeh Noughani
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Land Use Change ◽  
Agricultural Development ◽  
Erosion Risk ◽  
Before And After ◽  
Global Soil ◽  
Major Floods ◽  
The Impact

Abstract Floods cause great damage to ecosystems and are among the main agents of soil erosion. Given the importance of soils for the functioning of ecosystems and development and improvement of bio-economic conditions, the risk and rate of soil erosion was assessed using the RUSLE model in Iran’s Lorestan province before and after a period of major floods in late 2018 and early 2019. Furthermore, soil erosion was calculated for current and future conditions based on the Global Soil Erosion Modeling Database (GloSEM). The results showed that agricultural development and land use change are the main causes of land degradation in the southern and central parts of the study area. The impact of floods was also significant since our evaluations showed that soil erosion increased from 4.12 t ha-1 yr-1 before the floods to 10.93 t ha-1 yr-1 afterwards. Field surveying using 64 ground control points determined that erodibility varies from 0.17 to 0.49% in the study area. Orchards, farms, rangelands and forests with moderate or low vegetation cover were the most vulnerable land uses to soil erosion. The GloSEM modeling results revealed that climate change is the main cause of change in the rate of soil erosion. Combined land use change-climate change simulation showed that soil erosion will increase considerably in the future under SSP1-RCP2.6, SSP2-RCP4.5, and SSP5-RCP8.5 scenarios. In the study area, both natural factors, i.e. climate change and human factors such as agricultural development, population growth, and overgrazing are the main drivers of soil erosion.

Human-induced climate change: the impact of land-use change

2018 ◽  
Vol 135 (3-4) ◽  
pp. 1031-1044 ◽  
Author(s):  
Thomas Gries ◽  
Margarete Redlin ◽  
Juliette Espinosa Ugarte
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
The Impact
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