scholarly journals Effects of Climate and Land Use on Herbaceous Species Richness and Vegetation Composition in West African Savanna Ecosystems

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Issouf Zerbo ◽  
Markus Bernhardt-Römermann ◽  
Oumarou Ouédraogo ◽  
Karen Hahn ◽  
Adjima Thiombiano
Keyword(s):  
Land Use ◽  
Species Richness ◽  
West African ◽  
Herbaceous Species ◽  
Vegetation Composition ◽  
Importance Value ◽  
African Savanna ◽  
Herbaceous Vegetation ◽  
Mixed Effect ◽  
The Impact

West African Savanna ecosystems are undergoing severe changes in their vegetation composition due to the impact of human land use and changes in climatic conditions. This study aims to examine the effect of climate, land use, and their interaction on species richness and composition of West African herbaceous vegetation. Plot based vegetation sampling was done in Burkina Faso. Specific richness and diversity indices were used to determine the effect of land use, climate, and their interaction. An importance value was computed to determine herbaceous species dominating the communities. Frequency of species is used to examine their distribution pattern. The results showed that climate significantly influenced herbaceous specific richness more than land use. However, land use had a significant effect on herbaceous vegetation composition. Herbaceous species diversity changed with environmental conditions. The floristic composition of dominant species is driven by both climate and land use. The frequency of distribution demonstrated that herbaceous species occurrences were more influenced by the mixed effect of climate and land use than their separate effects. Occasional and rare species are the most important part of herbaceous vegetation. Thus heterogeneity of Savanna ecosystem and vulnerability of herbaceous species are high.

scholarly journals DISPERSAL POTENTIAL OF HERBACEOUS SPECIES ACCORDING TO CLIMATE, LAND USE AND HABITAT CONDITIONS IN WEST AFRICAN SAVANNAH

2017 ◽  
Vol 332 ◽  
pp. 69-87 ◽  
Author(s):  
Issouf Zerbo ◽  
Karen Hahn ◽  
Markus Bernhardt-Römermann ◽  
Oumarou Ouédraogo ◽  
Adjima Thiombiano
Keyword(s):  
Land Use ◽  
Principal Component ◽  
Climatic Conditions ◽  
West African ◽  
Herbaceous Species ◽  
Dispersal Patterns ◽  
Herbaceous Vegetation ◽  
The North ◽  
High Dispersal ◽  
Dispersal Potential

According to environmental predictions, West Africa is becoming vulnerable to the adverse effects of climate change and land use dis- turbance. Herbaceous vegetation is the most sensitive to these effects. To assess the poten- tial of species to cope with these changes, this study investigated the dispersal potential of different herbaceous species. Data on her- baceous plant composition and environmen- tal parameters were collected along climate, land use and habitat gradients in West Afri- can savannah areas, as well as the diaspores of all herbaceous species encountered. Their traits were described in order to document the diversity of diaspore categories in herbaceous savannah vegetation. Based on an occurrence diagram, variations in dissemination patterns within families were identified. The dispersal potential of each species was determined on the basis of their patterns of dispersal. A hie- rarchical classification method was used to establish a dispersal typology, and principal component analysis was applied to identify the environmental conditions that account for their patterns of dispersal. The results show that the diaspores of herbaceous spe- cies can be classified according to fruit type, diaspore type, presence of heterodiaspory, exposure of diaspores, number of seeds per diaspore, diaspore morphology, shape of diaspores and pattern of dispersal. Poaceae, the most abundant family in savannah areas, have six patterns of dispersal. Most species have more than one pattern, and species with high dispersal potential (85.43%) dominate the herbaceous vegetation. Four groups of herbaceous species were identified according to their dispersal patterns. Potentially epizoo- chorous and anemochorous species (39.25% of the flora) were more related to village areas independently of climatic conditions and habi- tat types. Potentially endozoochorous and dysozoochorous species (31.06% of the flora) were more related to fresh and dry habitats in protected areas of the North and South Suda- nian zones. Potentially hydrochorous species (12.63% of the flora) were related to wet habi- tats but were more prominent in the Sahel, and potentially autochorous species (17.06% of the flora) were more related to bowé habi- tats in the southern Sudanian zone. Our study showed that all herbaceous species have good dispersal potential, which might enable them to persist in West African savannahs despite the severe climatic changes predicted.

scholarly journals Native forests but not agroforestry systems preserve arbuscular mycorrhizal fungal species richness in southern Ethiopia

Mycorrhiza ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 749-759
Author(s):  
Zerihun Belay ◽  
Mesele Negash ◽  
Janne Kaseva ◽  
Mauritz Vestberg ◽  
Helena Kahiluoto
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Species Composition ◽  
Arbuscular Mycorrhizal ◽  
Soil Samples ◽  
Southern Ethiopia ◽  
Native Forest ◽  
Native Forests ◽  
Land Use Types ◽  
The Impact

Abstract The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.

scholarly journals The environment they lived in: anthropogenic changes in local and regional vegetation composition in eastern Fennoscandia during the Neolithic

2020 ◽  
Author(s):  
Teija Alenius ◽  
Laurent Marquer ◽  
Chiara Molinari ◽  
Maija Heikkilä ◽  
Antti Ojala
Keyword(s):  
Land Use ◽  
Sediment Cores ◽  
Regional Scale ◽  
Reconstruction Algorithm ◽  
Land Uses ◽  
Neolithic Period ◽  
Vegetation Composition ◽  
Fire Dynamics ◽  
Disturbance Processes ◽  
The Impact

Abstract Understanding about regional versus local changes in vegetation is critical in answering archaeological questions, in particular at a time when humans are assumed to have caused higher disturbances at local scales rather than regional scales; this is the case during the Neolithic. The aim of this paper is to assess the impact of Neolithic land use on regional and local vegetation dynamics, plant composition and disturbance processes (e.g. fire) in eastern Fennoscandia. We apply the Landscape Reconstruction Algorithm (LRA) to high-resolution pollen records from three lacustrine sediment cores that cover the Neolithic period. We calculate changes in vegetation composition and the rate of plant compositional change. Fire dynamics are estimated as an indicator of land use, although fire can result from both natural and anthropogenic disturbances. Our results show that during the Early Neolithic, changes were mainly driven by natural and climate-induced factors and vegetation composition and fire activity were similar at both regional and local scales. From ca. 4000 bc onwards, trends in vegetation and fire dynamics start to differ between regional and local scales. This is due to local land uses that are overshadowed at the regional scale by climate-induced factors. The use of the LOVE model in pollen analyses is therefore very useful to highlight local land uses that are not visible by using REVEALS.

scholarly journals Modeling gas exchange and biomass production in West African Sahelian and Sudanian ecological zones

2021 ◽  
Vol 14 (6) ◽  
pp. 3789-3812
Author(s):  
Jaber Rahimi ◽  
Expedit Evariste Ago ◽  
Augustine Ayantunde ◽  
Sina Berger ◽  
Jan Bogaert ◽  
...  
Keyword(s):  
Land Use ◽  
West Africa ◽  
Aboveground Biomass ◽  
Carbon Stocks ◽  
West African ◽  
Biogeochemical Model ◽  
Area Index ◽  
Wide Range ◽  
The Impact ◽  
Mean Square Errors

Abstract. West African Sahelian and Sudanian ecosystems provide essential services to people and also play a significant role within the global carbon cycle. However, climate and land use are dynamically changing, and uncertainty remains with respect to how these changes will affect the potential of these regions to provide food and fodder resources or how they will affect the biosphere–atmosphere exchange of CO2. In this study, we investigate the capacity of a process-based biogeochemical model, LandscapeDNDC, to simulate net ecosystem exchange (NEE) and aboveground biomass of typical managed and natural Sahelian and Sudanian savanna ecosystems. In order to improve the simulation of phenology, we introduced soil-water availability as a common driver of foliage development and productivity for all of these systems. The new approach was tested by using a sample of sites (calibration sites) that provided NEE from flux tower observations as well as leaf area index data from satellite images (MODIS, MODerate resolution Imaging Spectroradiometer). For assessing the simulation accuracy, we applied the calibrated model to 42 additional sites (validation sites) across West Africa for which measured aboveground biomass data were available. The model showed good performance regarding biomass of crops, grass, or trees, yielding correlation coefficients of 0.82, 0.94, and 0.77 and root-mean-square errors of 0.15, 0.22, and 0.12 kg m−2, respectively. The simulations indicate aboveground carbon stocks of up to 0.17, 0.33, and 0.54 kg C ha−1 m−2 for agricultural, savanna grasslands, and savanna mixed tree–grassland sites, respectively. Carbon stocks and exchange rates were particularly correlated with the abundance of trees, and grass biomass and crop yields were higher under more humid climatic conditions. Our study shows the capability of LandscapeDNDC to accurately simulate carbon balances in natural and agricultural ecosystems in semiarid West Africa under a wide range of conditions; thus, the model could be used to assess the impact of land-use and climate change on the regional biomass productivity.

Impacts of land-use on West African savanna vegetation: a comparison between protected and communal area in Burkina Faso

2011 ◽  
Vol 20 (14) ◽  
pp. 3341-3362 ◽  
Author(s):  
Blandine Marie Ivette Nacoulma ◽  
Katharina Schumann ◽  
Salifou Traoré ◽  
Markus Bernhardt-Römermann ◽  
Karen Hahn ◽  
...  
Keyword(s):  
Land Use ◽  
Burkina Faso ◽  
West African ◽  
African Savanna ◽  
Savanna Vegetation ◽  
Communal Area

scholarly journals Estimating the potential biodiversity impact of redeveloping small urban spaces: the Natural History Museum’s grounds

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3914
Author(s):  
Helen R.P. Phillips ◽  
Sandra Knapp ◽  
Andy Purvis
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Natural History ◽  
Species Density ◽  
Urban Setting ◽  
Small Scale ◽  
Ecological Data ◽  
Current Form ◽  
Habitat Area ◽  
The Impact

Background With the increase in human population, and the growing realisation of the importance of urban biodiversity for human wellbeing, the ability to predict biodiversity loss or gain as a result of land use change within urban settings is important. Most models that link biodiversity and land use are at too coarse a scale for informing decisions, especially those related to planning applications. Using the grounds of the Natural History Museum, London, we show how methods used in global models can be applied to smaller spatial scales to inform urban planning. Methods Data were extracted from relevant primary literature where species richness had been recorded in more than one habitat type within an urban setting. As within-sample species richness will increase with habitat area, species richness estimates were also converted to species density using theory based on the species–area relationship. Mixed-effects models were used to model the impact on species richness and species density of different habitat types, and to estimate these metrics in the current grounds and under proposed plans for redevelopment. We compared effects of three assumptions on how within-sample diversity scales with habitat area as a sensitivity analysis. A pre-existing database recording plants within the grounds was also used to estimate changes in species composition across different habitats. Results Analysis estimated that the proposed plans would result in an increase of average biodiversity of between 11.2% (when species density was modelled) and 14.1% (when within-sample species richness was modelled). Plant community composition was relatively similar between the habitats currently within the grounds. Discussion The proposed plans for change in the NHM grounds are estimated to result in a net gain in average biodiversity, through increased number and extent of high-diversity habitats. In future, our method could be improved by incorporating purposefully collected ecological survey data (if resources permit) and by expanding the data sufficiently to allow modelling of the temporal dynamics of biodiversity change after habitat disturbance and creation. Even in its current form, the method produces transparent quantitative estimates, grounded in ecological data and theory, which can be used to inform relatively small scale planning decisions.

scholarly journals Biodiversity Impacts of Increased Ethanol Production in Brazil

Land ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 12
Author(s):  
A.S. Duden ◽  
P.A. Verweij ◽  
A.P.C. Faaij ◽  
D. Baisero ◽  
C. Rondinini ◽  
...  
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Land Use Change ◽  
Ethanol Production ◽  
Atlantic Forest ◽  
Land Use Changes ◽  
Future Research ◽  
Nature Protection ◽  
Indirect Land Use Change ◽  
The Impact

Growing domestic and international ethanol demand is expected to result in increased sugarcane cultivation in Brazil. Sugarcane expansion currently results in land-use changes mainly in the Cerrado and Atlantic Forest biomes, two severely threatened biodiversity hotspots. This study quantifies potential biodiversity impacts of increased ethanol demand in Brazil in a spatially explicit manner. We project changes in potential total, threatened, endemic, and range-restricted mammals’ species richness up to 2030. Decreased potential species richness due to increased ethanol demand in 2030 was projected for about 19,000 km2 in the Cerrado, 17,000 km2 in the Atlantic Forest, and 7000 km2 in the Pantanal. In the Cerrado and Atlantic Forest, the biodiversity impacts of sugarcane expansion were mainly due to direct land-use change; in the Pantanal, they were largely due to indirect land-use change. The biodiversity impact of increased ethanol demand was projected to be smaller than the impact of other drivers of land-use change. This study provides a first indication of biodiversity impacts related to increased ethanol production in Brazil, which is useful for policy makers and ethanol producers aiming to mitigate impacts. Future research should assess the impact of potential mitigation options, such as nature protection, agroforestry, or agricultural intensification.

Human-disturbed landscapes: effects on composition and integrity of riparian woody vegetation in the Tagus River basin, Portugal

2005 ◽  
Vol 32 (1) ◽  
pp. 30-41 ◽  
Author(s):  
FRANCISCA C. AGUIAR ◽  
MARIA TERESA FERREIRA
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Environmental Factors ◽  
Human Disturbance ◽  
Riparian Vegetation ◽  
Woody Vegetation ◽  
Small Scale ◽  
Riparian Ecosystems ◽  
Average Width ◽  
The Impact

Human activities within fluvial corridors and surrounding landscapes have persistently stressed riparian ecosystems, particularly in Iberian Mediterranean-type streams. The impact of human disturbance relative to natural environmental factors in shaping riparian vegetation is still poorly understood. Both regional variables (such as altitude and precipitation), and site-specific characteristics (such as substrate and riverbank modifications) were analysed as potential determinants of riparian vegetation patterning to determine the relative influences of the diverse land-use types and environmental factors on the composition (including floristic species richness and percentage cover of trees, shrubs and woody climbers) and integrity (width of riparian woods and patterns of longitudinal continuity) of riparian woods in eight river basins of the Tagus fluvial system (Portugal). There was patchy establishment of riparian woods, with generally low average width and low species richness, as well as significant inter-basin differences and upstream-downstream variations in riparian features. Species distribution was clearly determined by environmental factors, such as human disturbance on the riverbanks and geological background, and the environmental variables and the land use in the river valley partially explained the integrity of riparian woody vegetation. The results highlight the predictive capability of reach-level features; it appears that, linked with the geomorphological and climate context, small-scale human disturbances on riparian corridors play a major role in explaining the remaining biological variability.

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