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An Assessment of Vegetation Metrics and Plot Types to Measure Seasonal Variation and Grazing Effects on Riparian Plant CommunitiesLaine, Caroline M. 01 December 2011 (has links)
The variation that exists in both time and space in riparian plant communities was explored in five streams within the Salmon National Forest and surrounding Bureau of Land Management (BLM) lands of central-eastern Idaho that are managed for cattle grazing. In this study, we evaluated the ability of commonly used vegetation metrics (live vegetation cover, species richness, % forb, litter, bare ground, wetland indicator rating, % graminoid, bank alteration, soil compaction, and % native) and different plot types (static or dynamic) to assess changes in plant communities over time and in areas grazed by cattle. We were particularly interested in evaluating the stability of metrics over time and the responsiveness of metrics to cattle grazing. We found that the metrics wetland indicator rating, % graminoid, and % native were stable across the season, while live vegetation cover, species richness, % forb, litter, bare ground, bank alteration, and soil compaction were affected by seasonal variation. The metrics that responded to grazing similarly at all streams and sites were live vegetation cover, litter, bare ground, and bank alteration, while species richness, % forb, wetland indicator rating, % graminoid, soil compaction, and % native responded differently to cattle grazing at individual streams. The metrics that were most sensitive to cattle grazing within the season were live vegetation cover, species richness, % forb, litter, and bare ground. Plot type did not have an effect on the majority of the metrics at the majority of the streams. This information can be used by land managers to determine which metrics are suitable for short- and long-term monitoring, and which ones are appropriate for monitoring the effects of cattle grazing.
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The diversity of moths in a nature reserve in the Northern Cape, South Africa : Variation over time, depending on abiotic factors and differences between areas with different grazing typesJarl, Nellie January 2023 (has links)
Land use changes globally have significant impacts on flora and fauna. In South Africa, extensive land is used for grazing by both domestic livestock and farmed native grazers. However, the effects of different grazing types on vegetation and fauna remain poorly understood. The Northern Cape, the country's largest province with a substantial agricultural sector, lacks comprehensive insect research. This study aimed to investigate moth diversity in an unstudied area, assessing species composition, dung beetle abundance, vegetational patterns, and the influence of abiotic factors and trap types on catches of moth in areas with varying grazing practices. Habitat types and habitat preferences were also examined. The research was conducted in the mid-north region of the Kalahari, Northern Cape province, between February and April 2023. Moths were captured using three different light sources, three times a week, and a subset of moths were counted and registered. The findings revealed the presence of at least 142 macromoth morphospecies, with higher abundance and species richness in areas grazed by domestic animals compared to native grazers. Dung beetle abundance was also greater in these areas. Notably, different habitats exhibited variations in moth occurrence, with specific morphospecies showing preferences for particular habitats. Plant species richness was higher in areas grazed by native grazers, while vegetational cover was greater in areas grazed by domestic animals. The study could show influence of moonlight, temperature, and windspeed on moth catches, and trap types affected the number of morphospecies captured. Surprisingly, the results contradict previous studies that suggested higher diversity in areas grazed by native grazers. Possible explanations include differences between the two areas in how beneficial the surrounding areas are, differences in abiotic factors, environmental productivity, habitat heterogeneity and plant species composition. Further studies of differences between areas with different grazing types in similar regions are needed to validate the findings of this study.
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Evaluation of selected soil properties in semi-arid communal rangelands in the Western Bophirima district, South Africa / Abdoulaye Saley MoussaSaley Moussa, Abdoulaye January 2007 (has links)
Concerns were raised over the past decades, on the degradation condition of arid and
semi-arid rangelands in South Africa, mainly in areas under communal land
management. Baseline information on soil quality is essential to monitor changes in land
conditions and assess impacts of land uses and management over time. The objectives of
this study, initiated within the framework of the Desert Margins Program, were to
characterize and establish baseline indicators of soil quality health, and to investigate
the potential effects of grazing and exclusion management (hypothesized as grazing
effect) on selected soil properties in the western Bophirima District in South Africa.
Soils were characterized for physical, chemical, enzymatic activity and microbial
biomass properties, and grazing effects were evaluated on selected properties. The
aboveground herbaceous species composition and biomass production were also
determined. Sandy, poor fertile soils (low organic carbon and phosphorus)
characterized all sites. Various levels of enzymatic and microbial biomass were
recorded at the sites. Grazing had no significant effects on most of soil chemical
properties, but did affect selected enzymatic activities, site-specifically. No significant
differences of grazing effects were observed on soil microbial biomass. The
inconsistent responses of soil properties across the sites prompt to caution regarding
the generalization and/or extrapolation of grazing effects to other areas, without
consideration of the prevailing environmental and management characteristics to each
site. Notwithstanding the alarming plea about degradation at these communal sites,
indicators of soil quality did not significantly differ between communal and
surrounding commercial and/or game managed areas, despite their apparent vegetation
degradation. The results showed that rangeland under the communal management
were characterized by increaser species of low grazing value, but this situation did not
necessarily interpret severe soil degradation as tacitly described. Soil degradation
depends on land use, management and environmental conditions, and references are
needed to assess degradation. Important interrelationships between the aboveground
vegetation and soil belowground activity were observed. This emphasized the need to
integrate both soil and vegetation into rangeland monitoring, as these interrelationships
and associated ecological processes sustain rangeland health. Further research is needed to re-examine the "inferred degradation of rangelands in communal areas,
taking into consideration their history, and using appropriate baselines and references
sites. Only then, can degradation trends and hotspots be identified and thereof,
appropriate management decisions (through participatory research) taken locally to
combat degradation and sustain long-term rangeland resources uses. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.
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Evaluation of selected soil properties in semi-arid communal rangelands in the Western Bophirima district, South Africa / Abdoulaye Saley MoussaSaley Moussa, Abdoulaye January 2007 (has links)
Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.
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Evaluation of selected soil properties in semi-arid communal rangelands in the Western Bophirima district, South Africa / Abdoulaye Saley MoussaSaley Moussa, Abdoulaye January 2007 (has links)
Concerns were raised over the past decades, on the degradation condition of arid and
semi-arid rangelands in South Africa, mainly in areas under communal land
management. Baseline information on soil quality is essential to monitor changes in land
conditions and assess impacts of land uses and management over time. The objectives of
this study, initiated within the framework of the Desert Margins Program, were to
characterize and establish baseline indicators of soil quality health, and to investigate
the potential effects of grazing and exclusion management (hypothesized as grazing
effect) on selected soil properties in the western Bophirima District in South Africa.
Soils were characterized for physical, chemical, enzymatic activity and microbial
biomass properties, and grazing effects were evaluated on selected properties. The
aboveground herbaceous species composition and biomass production were also
determined. Sandy, poor fertile soils (low organic carbon and phosphorus)
characterized all sites. Various levels of enzymatic and microbial biomass were
recorded at the sites. Grazing had no significant effects on most of soil chemical
properties, but did affect selected enzymatic activities, site-specifically. No significant
differences of grazing effects were observed on soil microbial biomass. The
inconsistent responses of soil properties across the sites prompt to caution regarding
the generalization and/or extrapolation of grazing effects to other areas, without
consideration of the prevailing environmental and management characteristics to each
site. Notwithstanding the alarming plea about degradation at these communal sites,
indicators of soil quality did not significantly differ between communal and
surrounding commercial and/or game managed areas, despite their apparent vegetation
degradation. The results showed that rangeland under the communal management
were characterized by increaser species of low grazing value, but this situation did not
necessarily interpret severe soil degradation as tacitly described. Soil degradation
depends on land use, management and environmental conditions, and references are
needed to assess degradation. Important interrelationships between the aboveground
vegetation and soil belowground activity were observed. This emphasized the need to
integrate both soil and vegetation into rangeland monitoring, as these interrelationships
and associated ecological processes sustain rangeland health. Further research is needed to re-examine the "inferred degradation of rangelands in communal areas,
taking into consideration their history, and using appropriate baselines and references
sites. Only then, can degradation trends and hotspots be identified and thereof,
appropriate management decisions (through participatory research) taken locally to
combat degradation and sustain long-term rangeland resources uses. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.
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Sustaining the Allideghi Grassland of Ethiopia: Influence of Pastoralism and Vegetation ChangeKebede, Almaz Tadesse 01 May 2009 (has links)
The Allideghi Wildlife Reserve in the Amibara District of Afar Regional State, Ethiopia, has international significance for harboring endangered Grevy's Zebra and other wildlife dependent on grasslands. The reserve is increasingly used by pastoral people and their herds. Impacts of livestock on native vegetation include direct effects of grazing and indirect effects from livestock-facilitated dispersal of an invasive plant, Prosopis juliflora. The main research objective was to determine effects of pastoralism and vegetation change on prospects for sustaining the Allideghi Wildlife Reserve as grassland habitat for Grevy's Zebra. Methods included use of driving surveys to quantify resource use by herbivores, vegetation analysis, and engagement with local people. Resource-use patterns of livestock across the Allideghi grassland were often positively affected by proximity of water, while that for wild ungulates was often negatively affected by proximity of people. Livestock concentration at a major borehole has created a large piosphere with concomitant reductions in herbaceous standing-crop, productivity, and species richness; plant species have shifted from grasses to forbs in severely grazed sites. Vegetation further from the borehole was resilient in response to moderate grazing pressure in terms of species composition and productivity. Since being introduced at a nearby commercial plantation in the 1970s, P. juliflora has been dispersed to the Allideghi Wildlife Reserve via livestock; cattle, sheep, and goats eat the pods and deposit seeds in manure at settlements and favored foraging areas. Prosopis juliflora greatly reduced species richness and basal cover of native herbaceous vegetation in the Allideghi grassland. Analysis of remotely sensed images from the past 30 years indicated major land-use change in the district due to agricultural expansion as well as land-cover change due to Prosopis encroachment and heavy grazing. Recent efforts have been undertaken by various agencies to control P. juliflora, via harvest in the district, but this has yielded variable and often negative results. Without a concerted effort to limit livestock grazing and control spread of P. juliflora, the future for the grassland and wildlife at the Allideghi Wildlife Reserve is grim. Agencies and policy makers need to promote science- and community-based approaches to help rectify the situation. (311 pages)
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