scholarly journals An Assessment of Multiple Drivers Determining Woody Species Composition and Structure: A Case Study from the Kalahari, Botswana

Land ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 122 ◽  
Author(s):  
Meyer ◽  
Holloway ◽  
Christiansen ◽  
Miller ◽  
D’Odorico ◽  
...  
Keyword(s):  
Species Abundance ◽  
Woody Species ◽  
Environmental Variable ◽  
Woody Vegetation ◽  
Tobit Regression ◽  
Species Identity ◽  
Rainfall Gradient ◽  
Composition And Structure ◽  
Species Richness And Abundance ◽  
The Impact

Savannas are extremely important socio-economic landscapes, with pastoralist societies relying on these ecosystems to sustain their livelihoods and economy. Globally, there is an increase of woody vegetation in these ecosystems, degrading the potential of these multi-functional landscapes to sustain societies and wildlife. Several mechanisms have been invoked to explain the processes responsible for woody vegetation composition; however, these are often investigated separately at scales not best suited to land-managers, thereby impeding the evaluation of their relative importance. We ran six transects at 15 sites along the Kalahari transect, collecting data on species identity, diversity, and abundance. We used Poisson and Tobit regression models to investigate the relationship among woody vegetation, precipitation, grazing, borehole density, and fire. We identified 44 species across 78 transects, with the highest species richness and abundance occurring at Kuke (middle of the rainfall gradient). Precipitation was the most important environmental variable across all species and various morphological groups, while increased borehole density and livestock resulted in lower bipinnate species abundance, contradicting the consensus that these managed features increase the presence of such species. Rotating cattle between boreholes subsequently reduces the impact of trampling and grazing on the soil and maintains and/or reduces woody vegetation abundance.

scholarly journals The influence of the 1991/92 drought on the woody vegetation of the Kruger National Park

Koedoe ◽  
1995 ◽  
Vol 38 (2) ◽  
Author(s):  
A.J. Viljoen
Keyword(s):  
National Park ◽  
Woody Species ◽  
Aerial Photographs ◽  
Woody Vegetation ◽  
General Area ◽  
Variable Intensity ◽  
The North ◽  
Olifants River ◽  
Area North ◽  
The Impact

All observations and data related to the impact of the 1991/92 drought on the woody vegetation, excluding the riverine vegetation of major rivers, are summarised. This includes data from a visual estimate of damage from aerial photographs, surveys on selected sites, and general observations. Despite lower rainfall, the area north of the Olifants River (excluding the far-northern part) was less affected than the area south of it, suggesting that the woody vegetation in the north is more adapted to drought. A characteristic of the drought was the localised distribution pattern and variable intensity of damage to the same species in the same general area. Information on 31 species are presented briefly. Although a large number of woody species was to some extent damaged, when the woody vegetation is considered as a whole, the influence of the drought was not very severe.

Dynamique de la végétation d'emprises de lignes de transport d'énergie

1984 ◽  
Vol 62 (8) ◽  
pp. 1730-1738
Author(s):  
M. Darveau ◽  
P. Bellefleur
Keyword(s):  
Woody Species ◽  
Power Line ◽  
Power Lines ◽  
Underlying Structure ◽  
Dichlorophenoxyacetic Acid ◽  
Border Line ◽  
Control Power ◽  
Composition And Structure ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

We made a preliminary study of the impact of phytocides on plant dynamics in the corridors of Hydro-Québec power lines. Three hypotheses were tested: the first assumed that the phytocides changed vegetation composition and structure in the corridors; the second assumed that the corridor under the power line favored the development of an ecotone at its border with the forest; the third assumed that the method used for initial cutting of the corridors (bulldozer or chain saw) affected the forthcoming vegetation for over 15 years. Vegetation was sampled on one control power line and four power lines maintained with mixtures of picloram, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, and sodium trichloroacetate. Multidimensional statistical analysis was used to show the underlying structure of the raw data and to test the hypotheses. We found out that phytocides are very efficient on woody species to the advantage of herbs, mostly grass, which invaded the corridors and created rather stable artificial communities. No significant ecotone was found at the border line of the corridors and the forest. The influence of the method for initial cutting of the corridors, although severe the first few years, disappeared after about 10 years under the action of the phytocides.

scholarly journals Effects of Human Impact on Miombo Woodland in Northern Malawi

2010 ◽  
Vol 13 ◽  
pp. 22-34
Author(s):  
Tina Vanadis Bundschuh ◽  
Rüdiger Wittig ◽  
Karen Hahn
Keyword(s):  
Plant Diversity ◽  
Rural Population ◽  
Vegetation Type ◽  
Woody Species ◽  
Wild Plants ◽  
Wild Plant ◽  
Woody Vegetation ◽  
Miombo Woodland ◽  
Wild Plant Species ◽  
The Impact

Miombo woodland is found throughout the Zambezian regional centre of endemism where most of the rural population make use of its wild plant species. This article presents the results of a study on the composition of the woody vegetation and its anthropogenous alteration in northern Malawi with particular respect to the impact caused by the collection of wild plants. The main vegetation type in this area is miombo woodland which is composed of 80 woody species. The collection of wild plants does not show an effect on the plant diversity but effects are visible in the decreasing number of tall trees.

scholarly journals Browser impacts in Mapungubwe National Park, South Africa: Should we be worried?

Koedoe ◽  
2016 ◽  
Vol 58 (1) ◽  
Author(s):  
Corli Coetsee ◽  
Benjamin J. Wigley
Keyword(s):  
South Africa ◽  
Species Diversity ◽  
National Park ◽  
Woody Species ◽  
Woody Vegetation ◽  
Vegetation Types ◽  
Medium Term ◽  
Management Interventions ◽  
Rocky Outcrops ◽  
The Impact

This study explores the impact of browsers on vegetation types within the Mapungubwe National Park and specifically whether rocky outcrops or ridges in the park serve as refugia from browsers, particularly elephants. We sampled 80 transects at 20 sites and recorded 1740 plants comprising 65 species. We found that a high proportion (> 80%) of the woody vegetation sampled indicated browser utilisation. Although certain woody species (e.g. Albizia harveyi, Boscia albitrunca, Lannea schweinfurthii) appeared to be preferred by browsers, browsing levels were relatively high among all woody species. High levels of browsing by herbivores other than elephants suggest that they have a significant impact on the park’s vegetation. We did not find that rocky ridges acted as refugia to browsers, but instead found that vegetation in rocky ridges was more severely impacted by browsers than vegetation in flat areas, despite vegetation being more accessible in flat areas. If elephant numbers continue to increase at the current rate (e.g. elephant numbers doubled between 2007 and 2010), we predict that some of the heavily utilised species will become locally rare over time.Conservation implications: High levels of browsing by both elephant and smaller herbivores contribute to significant impacts on vegetation away from rivers in Mapungubwe National Park. Without management interventions that address both types of impact, structural and species diversity are bound to decrease over the short to medium term.

scholarly journals Fuelwood Harvest and No Harvest Effects on Forest Composition, Structure, and Diversity of Arasbaran Forests—A Case Study

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1631
Author(s):  
Sajad Ghanbari ◽  
Christel C. Kern
Keyword(s):  
Species Diversity ◽  
Tree Height ◽  
Woody Species ◽  
Forest Composition ◽  
Stem Density ◽  
Regeneration Status ◽  
Composition And Structure ◽  
Composition Structure ◽  
The Impact

The impact of fuelwood harvesting on forest structure and composition is not clear, especially on the understudied and scarce Arasbaran forests in Iran. This research compared woody species density, species diversity, forest composition, and regeneration status in areas of continuous and ceased fuelwood harvesting in Arasbaran forests. We expected fuelwood harvesting to decrease stem density, species diversity, tree size (diameter at the breast height (DBH) and height), and shift composition away from preferred fuelwood species. We measured woody species size and frequency and identified species in three fuelwood harvest and three no harvest sites, with six sample plots (100 m × 50 m) per site. Results tended to show differences in composition, diversity, woody species height, and density. Carpinus orientalis, a preferred fuelwood species, tended to be more dominant in no harvest (importance values index (IVI) = 173.4) than harvest areas (IVI = 4.4). The diversity or richness of woody species tended to be higher in harvest (20 ± 1 species per ha) than in no harvest (14 ± 2 species per ha) areas, and other measures of diversity supported this trend as well. Harvest areas tended to also be characterized by shorter tree height and lower density of trees, a higher density of regeneration, and fewer small pole-sized trees than no harvest areas. Ongoing fuelwood harvests may further shift composition and structure away from no harvest area, compromising future fuelwood availability, but further detailed research is needed. Close to nature practices may be useful in sustaining fuelwood harvest areas and diversifying areas where fuelwood harvesting has ceased.

The impact of feral camels (Camelus dromedarius) on woody vegetation in arid Australia

2016 ◽  
Vol 38 (2) ◽  
pp. 181 ◽  
Author(s):  
Jayne Brim Box ◽  
Catherine E. M. Nano ◽  
Glenis McBurnie ◽  
Donald M. Waller ◽  
Kathy McConnell ◽  
...  
Keyword(s):  
Woody Species ◽  
Woody Vegetation ◽  
Plant Populations ◽  
Large Mammal ◽  
Canopy Volume ◽  
Adult Tree ◽  
Management Project ◽  
Acacia Aneura ◽  
The Impact

Data on the extent of feral camel damage on trees and shrubs in inland Australia are scarce, and there is currently no universally accepted theoretical framework for predicting the impact of a novel large mammal browser on arid vegetation. In other (mainly mesic) grassy systems, large mammal browsers can strongly suppress woody biomass across landscapes by limiting the transition of saplings to adulthood and by significantly thinning adult tree canopies. The recent Australian Feral Camel Management Project provided an opportunity to assess the impacts of camel browsing on woody vegetation in inland Australia. We examined browsing intensity and severity (stunting and canopy loss) in 22 species of woody plants in camel-affected regions across inland Australia prior to camel removal operations. The severity of plant damage increased with camel density as both trees and shrub growth were strongly suppressed where camel densities exceeded 0.25 km–2. In most tree and shrub species tested, camel browsing significantly stunted plants, suggesting that camel browsing has long-term impacts on plant populations. Browsing also reduced canopy volume in several species, including the structurally important Acacia aneura F.Muell. ex Benth. Thus, in this dryland ecosystem, camels can curtail the regeneration and growth of woody species enough to threaten ecosystem health. To avoid adverse impacts on woody plant populations, camel densities should be maintained at 0.25 camels km–2 or less over as much of inland Australia as possible.

scholarly journals Vegetation Dynamics in the Northern Zones of Niger: Case of the Rural Commune of Tanout (Zinder) and Aderbissinat (Agadez)

2021 ◽  
Vol 2 (1) ◽  
pp. 30-36
Author(s):  
Abdoul Kader Soumaila Sina ◽  
Nouhou Ali ◽  
Amadou Garba ◽  
Bernard Minoungou
Keyword(s):  
Land Use ◽  
Vegetation Dynamics ◽  
Methodological Approach ◽  
Woody Species ◽  
Woody Vegetation ◽  
Landsat Images ◽  
Floristic Inventory ◽  
Northern Zone ◽  
The Impact ◽  
Land Use Maps

The present study conducted in the northern zone of Niger aims to show the impact of land use dynamics on woody vegetation. The methodological approach consisted in making in addition to the floristic surveys, the analysis of land use maps (LANDSAT images of the years 1975 and 2018). The floristic inventory allowed the identification of twenty-seven (27) woody species of which eleven (11) in Tanout and sixteen (16) in Aderbissinat. The most important families remain the Fabaceae-Mimosoideae which represent 37.5% at Aderbissinat and 45.45% at Tanout. The biological types remain dominated by microphanerophytes which dominate (86.67%), while for the phytogeographic types it is the Sudano-Zambezian and Sudanian species that dominate, with proportions respectively equal to 31.25%. There is a regression of woody vegetation at the level of these communes with a slight loss in Aderbissinat (60588,034 ha) and an accentuated degradation of vegetation in Tanout (781797,738 ha).

Income Diversification and Bank Efficiency in Vietnam

2017 ◽  
pp. 52-67
Author(s):  
Sang Nguyen Minh
Keyword(s):  
Regression Model ◽  
Commercial Banks ◽  
Banking System ◽  
Operational Efficiency ◽  
Commercial Banking ◽  
Tobit Regression ◽  
Income Diversification ◽  
Positive Effects ◽  
Study Results ◽  
The Impact

This study uses the DEA (Data Envelopment Analysis) method to estimate the technical efficiency index of 34 Vietnamese commercial banks in the period 2007-2015, and then it analyzes the impact of income diversification on the operational efficiency of Vietnamese commercial banks through a censored regression model - the Tobit regression model. Research results indicate that income diversification has positive effects on the operational efficiency of Vietnamese commercial banks in the research period. Based on study results, in this research some recommendations forpolicy are given to enhance the operational efficiency of Vietnam’s commercial banking system.

Labour-use Efficiency of Assam Gramin Vikash Bank: Branch- and District-level Analysis

2021 ◽  
pp. 232102222110243
Author(s):  
Mohuya Deb Purkayastha ◽  
Joyeeta Deb ◽  
Ram Pratap Sinha
Keyword(s):  
Efficiency Score ◽  
Significant Variable ◽  
Data Envelopment ◽  
Tobit Regression ◽  
Second Stage ◽  
Time Period ◽  
Use Efficiency ◽  
The Mean ◽  
The Impact ◽  
Observation Period

The present study estimated labour-use efficiency of 48 branches of Assam Gramin Vikash Bank at its branch level, covering three districts of Barak Valley, which falls under Silchar region of the bank for the time period from 2010–2011 to 2017–2018. The study applied data envelopment analysis for estimating labour-use efficiency. In the second stage, the study applied censored Tobit regression for determining the impact of several contextual variables on efficiency. The study reveals that the mean labour-use efficiency score of the selected branches is 76% when averaged for the in-sample branches over the observation period. Results of the Tobit regression identified cluster 2 and total business of the branches as the significant factors for determining efficiency and the number of employees as a significant variable influencing inefficiency. JEL Classifications: G2, G20, G21, J3

scholarly journals Assessing Habitat Vulnerability and Loss of Naturalness: Applying the GLOBIO3 Model in the Czech Republic

2021 ◽  
Vol 13 (10) ◽  
pp. 5355
Author(s):  
Vilém Pechanec ◽  
Ondřej Cudlín ◽  
Miloš Zapletal ◽  
Jan Purkyt ◽  
Lenka Štěrbová ◽  
...  
Keyword(s):  
Land Use ◽  
Czech Republic ◽  
Habitat Quality ◽  
Species Abundance ◽  
Biodiversity Loss ◽  
Infrastructure Development ◽  
Natural Habitats ◽  
The Czech Republic ◽  
New Equation ◽  
The Impact

Global and regional biodiversity loss is caused by several drivers including urban development, land use intensification, overexploitation of natural resources, environmental pollution, and climate change. The main aim of our study was to adapt the GLOBIO3 model to the conditions of the Czech Republic (CR) to assess loss of naturalness and biodiversity vulnerability at the habitat level on a detailed scale across the entire CR. An additional aim was to assess the main drivers affecting the biodiversity of habitat types. The GLOBIO3 model was adapted to CZ-GLOBIO by adapting global to local scales and using habitat quality and naturalness data instead of species occurrence data. The total mean species abundance (MSA) index of habitat quality, calculated from the spatial overlay of the four MSA indicators by our new equation, reached the value 0.62. The total value of MSA for natural and near-natural habitats was found to be affected mainly by infrastructure development and fragmentation. Simultaneously, intensity of land use change and atmospheric nitrogen deposition contributed primarily to the low total value of MSA for distant natural habitats. The CZ-GLOBIO model can be an important tool in political decision making to reduce the impact of the main drivers on habitat biodiversity in the CR.

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