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Evaluation of restoration and management actions in the Molopo savanna of South Africa :|ban integrative perspective / Christiaan Johannes HarmseHarmse, Christiaan Johannes January 2013 (has links)
The loss of ecosystem resilience and rangeland (often referred to as veld in South
Africa) productivity is a major problem in the semi-arid Savanna environments of
southern Africa. The over-utilization of rangelands in the Molopo region of the North-
West Province in South Africa has resulted in profound habitat transformations. A
common regional indicator of rangeland degradation is the imbalance in the grasswoody
ratio, characterized by a loss of grass cover and density with increased shrub
or tree density. This can result in major reductions of rangeland productivity for the
grazing animal, forcing land users to apply active or passive restoration actions to
improve rangeland condition, control the thickening of woody species (bush
thickening), mitigate economic losses and restoring the aesthetical value of the
Savanna environment for ecotourism and game hunting aspects.
This study formed part of the multinational EU-funded PRACTICE project
(“Prevention and restoration actions to combat desertification: an integrated
assessment”). The first aim of the study was to evaluate locally applied restoration
actions using a participatory approach, followed by interviews with certain
stakeholders that formed part of a multi-stakeholder platform (MSP) related to the
livestock and game farming community in the Molopo. Participants of the MSP
ranked indicators according to their relative importance regarding the restoration
actions on an individual basis. The individual ranking results were combined with
quantitative bio-physical and qualitative socio-economic measurements for each
indicator in a multi-criteria decision analysis (MCDA), whereby the alternative actions
were ranked according to their relevancy and performance. The results were then
shared with members of the MSP in order to stimulate discussion among the
members and contribute to the social learning of the project outcome.
The overall positive response and acceptance of results by members of the MSP
changed the perceptions and objectives of the land users regarding rangeland
management. This type of participatory assessment was therefore found to be very
promising in helping to identify more sustainable actions to mitigate rangeland
degradation in the Molopo Savanna region. There is, however, still an urgent need to
create legal policy frameworks and institution-building, to support local-level implementation in all socio-ecological and economic settings, particularly in
communal areas.
The second aim was to evaluate the effect of two chemical bush control actions
(chemical hand- (HC) and aeroplane control (AC)) as well as rotational grazing
(RGM) on the Molopo Savanna vegetation.
Results show that rangeland productivity, i.e. forage production and grazing
capacity, was found to be negatively related to the woody phytomass in the savanna
system studied. Bush thickening influenced grass species composition which was
commonly associated with a decline in the abundance of sub-climax to climax
grasses, respectively. All three actions (HC, AC & RGM) significantly reduced the
woody phytomass and increased forage production and grazing capacity.
Although AC resulted in the highest reduction of woody phytomass, the highest
forage production and grazing capacity was found under RGM. The second highest
grazing capacity was found in HC sites, which was due to a high abundance of
perennial, palatable climax grass species. Results from this study also show that the
patterns and compositions of grass species, grass functional groups (GFGs) and
woody densities indicated by RGM and chemical HC, best resemble a productive
and stable savanna system that provides important key resources to support both
grazing and browsing herbivores. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
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Terrestrial survey and remotely-sensed methods for detecting the biological soil crust components of rangeland conditionGhorbani, Ardavan January 2007 (has links)
This thesis considers various aspects of the use of ground-based methods and remote sensing of Biological Soil Crusts (BSC). They are mostly distributed in winter rainfall dominated areas such as those at Middleback Field Centre (MFC) in South Australia. They can be used potentially as an indicator of rangeland condition by estimating grazing pressure (trampling). Two BSC based indicators for rangeland condition assessment are species composition and cover. While there is strong agreement that BSC composition is a good indicator, there is less agreement that BSC cover alone is a good indicator. Although BSC have been included in previous remotely-sensed studies, their spectral characteristics, and hence their contributions to remotely-sensed spectral signatures, are not well known. Data collection methods were refined for suitable method selection, stratification and site characterization, and morphological/ functional group classification. Cover data of BSC were collected using a 100 m line-intercept method on the stratified land units and statistical analyses were based on the cover variance analyses. Spectra of BSC groups were collected and characterized for different remote sensing indices. Five grazing gradient models based on collected spectra were developed for the evaluation of BSC effect on remotely-sensed data. Both existing and newly developed remote sensing indices were examined for BSC detection. Sampling for cover of BSC in the field showed that there is indeed a detectable change with distance from water, suggesting that BSC cover can be used as an indicator of rangeland condition, provided that appropriate stratification of the study sites is carried out prior to sampling, and spectral differences in morphological and functional groups are taken into account. Spectral analysis of BSC components showed that different classes of organisms in the crusts have different spectral characteristics, and in particular, that the (commonly-used) perpendicular vegetation index (PD54) is not suitable for detecting BSC. On the other hand, ground-level spectral modelling showed that the Normalized Difference Vegetation Index (NDVI) and Soil Stability Index (SSI) did show a distinguishable contribution from BSC. A procedure for detecting cover of BSC was developed for image taken during the period after an effective rain, in contrast to the normal practice of selecting images of dry surfaces for interpretation. The most suitable intervals appears to be 2-4 days after rain in late autumn, winter and early spring. Of the existing indices, the SSI is the best for estimating cover of BSC from Landsat images. However, eight new indices, specifically designed for detection of BSC were developed during the cource of this work. The best results were obtained for indices using using the middle-infrared bands. These results are promising for application to rangeland monitoring and suggest that BSC cover is an important indicator of rangeland condition if appropriate stratification, classification and data-collection methods are used. The effects of BSC cover on a remotely-sensed method are considerable, and thus they can not be neglected during image interpretation. There are different phenological patterns for BSC, annual and perennial elements, thus there is the possibility for the selection of imagery based on each phenological stage to detect these elements. Application of certain indices such as the PD54 may create mis-estimation of land covers. Although some of the existing and newly developed indices had significant results for BSC cover estimation, there is a requirement for a standalone remotely-sensed method to conclude the best index.
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Impact of Prosopis (mesquite) invasion and clearing on ecosystem structure, function and agricultural productivity in semi-arid Nama Karoo rangeland, South AfricaNdhlovu, Thabisisani 03 1900 (has links)
Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: I evaluated the impact of Prosopis invasion and clearing on ecological structure, function and
agricultural productivity in heavily grazed Nama Karoo rangeland on two sheep farms near the
town of Beaufort West in the Western Cape Province of South Africa. My aims were to (1)
determine the effects of invasion and clearing on rangeland vegetation composition, diversity
(alien and indigenous species richness) and structure (alien and indigenous species cover), soil
vegetation cover (plant canopy and basal cover) and agricultural productivity (grazing capacity),
(2) describe the vegetation processes that underlay the invasion and clearing impacts and (3)
evaluate the success of clearing in facilitating unaided restoration of ecological structure,
function and agricultural productivity in formerly invaded rangeland. I hypothesised that
invasion would significantly change rangeland vegetation composition and structure, leading to
greater alien species richness and cover and lower indigenous species richness and cover while
clearing would lead to lower alien species diversity and cover and greater indigenous species
richness and cover. In addition I hypothesized that invasion would reduce rangeland plant
canopy and basal cover and grazing capacity while clearing would substantially increase them.
Finally I predicted that vegetation composition, alien and indigenous species cover and richness,
plant canopy and basal cover and grazing capacity would revert to pre-invasion status and levels
within four to six years of clearing.
My results suggest that in heavily grazed Nama Karoo rangeland Prosopis invasion (~15
percent canopy cover) and clearing can significantly change rangeland vegetation composition,
with invasion leading to greater alien species cover and lower indigenous species richness, while
clearing leads to lower alien species richness and cover and greater indigenous species richness
and cover. However invasion seems to have no effect on alien species richness and overall
indigenous species cover. Clearing appears to facilitate the spontaneous restoration of alien
species cover and indigenous species richness within four to six years but not species
composition, alien species richness and indigenous species cover. In addition my results also
indicate that Prosopis invasion can lower rangeland plant canopy and basal cover and grazing
capacity while clearing, even under heavy grazing, can substantially raise them. Clearing
however does not seem to facilitate the restoration of rangeland plant canopy and basal cover
and grazing capacity to pre-invasion levels within four to six years after clearing. / AFRIKAANSE OPSOMMING: Ek het die impak van Prosopis indringing en verwydering van indringers op ekologiese
struktuur, funksie en landbou produktiwiteit in ‘n swaar beweide Nama Karoo gebied op twee
skaapplase naby Beaufort-Wes in die Wes-Kaap provinsie van Suid-Afrika geëvalueer. My
doelwitte was om (1) te bepaal wat die gevolge van die indringing en verwydering van
indringers op die natuurlike plantegroei samestelling, diversiteit (uitheemse en inheemse
spesiesrykheid) en struktuur (uitheemse en inheemse spesies bedekking) sal wees, sowel as die
effek op plantegroei bedekking (kroon en basalebedekking) en landbou produktiwiteit
(weidingkapasiteit), (2) die plantegroei prosesse te beskryf wat onderliggend deur die impakte
van indringing en verwydering van indringers veroorsaak word, en (3) die sukses van die
verwydering van indringers te evalueer deur die fasilitering van blote restorasie van ekologiese
struktuur en funksie en landbou produktiwiteit in voorheen ingedringde gebiede. My hipotese is
dat indringing ‘n aansienlike verandering in natuurlike plantegroeisamestelling en struktuur sal
veroorsaak, wat sal lei tot groter uitheemse spesiesrykheid en bedekking met minder inheemse
spesiesrykheid en bedekking, terwyl die verwydering van indringers sou lei tot minder
uitheemse spesie diversiteit en bedekking met 'n groter inheemse spesiesrykheid en bedekking.
Verder vermoed ek dat indringing die natuurlike kroon- en basalebedekking en
weidingkapasiteit sal verminder, terwyl die verwydering van indringers dit aansienlik sal
verhoog. Ten slotte voorspel ek dat plantegroei samestelling, uitheemse en inheemse
spesiesbedekking en -rykheid, kroon- en basalebedekking en weidingkapasiteit sou terugkeer na
voor-indringing status en vlakke binne vier tot ses jaar na die verwydering van indringers.
My resultate daarop dat die indringing van Prosopis (~ 15 persent kroonbedekking) en die
verwydering van indringers in swaar beweide Nama Karoo gebiede ‘n aansienlike verandering
in die gebied se natuurlike plantegroei samestelling toon, waar indringing gelei het tot groter
uitheemse spesiesbedekking en minder inheemse spesiesrykheid, terwyl die verwydering van
indringers lei tot minder uitheemse spesiesrykheid en groter inheemse spesiesrykheid en -
bedekking. Dit lyk egter of indringing geen effek op uitheemse spesiesrykheid en algehele
inheemse spesiesbedekking het nie. Die verwydering van indringers blyk om die spontane
herstel van indringerbedekking en inheemse spesiesrykheid binne vier tot ses jaar te fasiliteer,
maar nie spesiesamestelling, uitheemse spesiesrykheid of inheemse spesiesbedekking nie.
Benewens dui my resultate ook aan dat Prosopis indringing die natuurlike kroon- en
basalebedekking sowel as weidingskapasiteit verlaag, terwyl die verwydering van indringers,
selfs onder swaar beweiding, die bedekking aansienlik kan verhoog. Verwydering van
indringers lyk egter nie asof dit die herstel van die gebied se natuurlike kroon- en
basalebedekking en weidingkapasiteit na voor-indringing vlakke toe kan fasiliteer binne vier tot
ses jaar na die verwydering van indringers nie.
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A comparison of standard scientific methods and pastoralists’ perceptions of vegetation responses to livestock exclusion in Namaqualand, South AfricaSnyman, Dirk 03 1900 (has links)
Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2010. / ENGLISH SUMMARY: Protected areas do not always achieve the desired level of biodiversity conservation, while
often reducing the welfare of indigenous communities by reducing availability of land for
subsistence. Traditional agricultural landscapes are significant biodiversity refugia and can
contribute meaningfully to conservation.
Rangelands comprise one-third to one-half of the world’s terrestrial surface, providing
livelihoods for around 220 million people, usually in a communal subsistence system.
Colonial practices impinged on traditional land-use practices with far-reaching social and
environmental impacts. This has resulted in management based on assumptions regarding
vegetation dynamics and traditional lifestyles that are increasingly shown to be inaccurate. A
comparison of a vegetation survey based on conventional scientific methods and a survey of
the perceptions of pastoralists was undertaken to highlight differences and similarities
between the two knowledge systems with the hope of providing guidelines for more
sustainable land-use practices in the communal rangelands of Namaqualand, South Africa.
Vegetation responses to removal of grazing pressure revealed complex interactions that do
not correspond with the prevailing management paradigm. Rather than a predictive
relationship between livestock and vegetation, environmental factors play a large role in
determining plant composition, abundance and cover. Pastoralists’ perceptions reflected this
complexity in rangeland resource dynamics. The impact of livestock on rangeland resource
dynamics was perceived by herders to be secondary to a range of environmental and climatic
factors. Both sets of results were at odds with the theories that currently govern management
in this system.
Studies in rangeland systems must take the complexity of the subject into account.
Research into such socio-ecological systems must take a multiplicity of factors – social,
environmental, economic, political and other – into account. Implications for management are
that it is inappropriate to adhere strictly to the conventional, conservative strategies that are
prescribed by conservation and agricultural authorities. Rather, a more flexible, opportunistic
grazing strategy would allow the persistence of traditional subsistence livelihoods without
serious negative consequences for biodiversity conservation. / AFRIKAANSR OPSOMMING: Die instelling van beskermde gebiede lewer nie altyd die gewenste vlak van
biodiversiteitsbewaring, terwyl die welvaart van plaaslike gemeenskappe dikwels daaronder
ly deur die afname in grond beskikbaar vir bestaanspraktyke. Tradisionele landboulandskappe
is beduidende biodiversiteitshawens wat ‘n belangrike bydrae tot bewaring kan maak.
Weivelde bevat ‘n derde tot ‘n helfte van die wêreld se landsoppervlakte en ondersteun
rondom 220 miljoen mense, gewoonlik binne ‘n gemeenskaplike bestaansstelsel.
Kolonialisasie het inbraak gemaak op tradisionele bestuurspraktyke, met verrykende sosialeen
omgewingsimpakte. Dit het gelei tot bestuurspraktyke gebaseer op standpunte oor
plantegroeidinamika en traditionele lewenswyses wat toenemend verkeerd bywys word. ‘n
Vergelyking van ‘n plantegroei opname gebaseer op konvensionele wetenskaplike metodes en
‘n opname van die standpunte van veewagters is onderneem om die verskille en
ooreenkomstes tussen die twee kennisstelsels uiteen te lê met die hoop om riglyne vir meer
volhoubare bestuurspraktyke in die meentgronde van Namakwaland, Suid-Afrika te verskaf.
Plantegroei reaksies tot die verwydering van weidingsdruk wys op komplekse interaksies
wat nie ooreenstem met die heersende bestuursparadigma. Eerder as ‘n voorspelbare
verwantskap tussen vee en plantegroei, omgewingsfaktore speel ‘n groot rol in die bepaling
van plantgemeenskapsamestelling, -getalle en grondbedekking. Die veewagters se standpunte
het hierdie kompleksiteit in plantegroeidinamika weerspiëel. Die impak van vee op die
weiveldhulpbron is deur veewagters as sekondêr beskou teenoor ‘n reeks omgewings- en
klimaatsfaktore. Beide stel resultate is in teenstelling met die teoriëe wat tans bestuur in
hierdie stelsel bepaal.
Studies in weiveldstelsels moet die kompleksiteit daarvan in ag neem. Navorsing oor
hierdie sosio-ekologiese stelsels moet ‘n verskeidenheid faktore – sosiale-, omgewings-,
ekonomiese-, politiese- en ander – in ag neem. Implikasies vir bestuur is dat dit onvanpas is
om te volhard met konvensionele, konservatiewe strategiëe voorgeskryf deur bewarings- en
landboukundige gesagte. ‘n Meer aanpasbare, voordeelnemende weidingsstrategie sal die
voortbestaan van traditionele bestaanslewenspraktyke toelaat sonder ernstige negatiewe
nagevolge vir biodiversiteitsbewaring.
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Rangeland degradation assessment using remote sensing and vegetation species.Manssour, Khalid Manssour Yousif. January 2011 (has links)
The degradation of rangeland grass is currently one of the most serious environmental problems in South Africa. Increaser and decreaser grass species have been used as indicators to evaluate rangeland condition. Therefore, classifying these species and monitoring their relative abundance is an important step for sustainable rangelands management. Traditional methods (e.g. wheel point technique) have been used in classifying increaser and decreaser species over small geographic areas. These methods are regarded as being costly and time-consuming, because grasslands usually cover large expanses that are situated in isolated and inaccessible areas. In this regard, remote sensing techniques offer a practical and economical means for quantifying rangeland degradation over large areas. Remote sensing is capable of providing rapid, relatively inexpensive, and near-real-time data that could be used for classifying and monitoring species. This study advocates the development of techniques based on remote sensing to classify four dominant increaser species associated with rangeland degradation namely: Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus and Aristida diffusa in Okhombe communal rangeland, KwaZulu-Natal, South Africa. To our knowledge, no attempt has yet been made to discriminate and characterize the landscape using these species as indicators of the different levels of rangeland degradation using remote sensing. The first part of the thesis reviewed the problem of rangeland degradation in South Africa, the use of remote sensing (multispectral and hyperspectral) and their challenges and opportunities in mapping rangeland degradation using different indicators. The concept of decreaser and increaser species and how it can be used to map rangeland degradation was discussed. The second part of this study focused on exploring the relationship between vegetation species (increaser and decreaser species) and different levels of rangeland degradation. Results showed that, there is significant relationship between the abundance and distribution of different vegetation species and rangeland condition.
The third part of the study aimed to investigate the potential use of hyperspectral remote sensing in discriminating between four increaser species using the raw field spectroscopy data and discriminant analysis as a classifier. The results indicate that the spectroscopic approach used in this study has a strong potential to discriminate among increaser species. These positive results prompted the need to scale up the method to airborne remote sensing data characteristics for the purpose of possible mapping of rangeland species as indicators of degradation. We investigated whether canopy reflectance spectra resampled to AISA Eagle resolution and random forest as a classification algorithm could discriminate between four increaser species. Results showed that hyperspectral data assessed with the random forest algorithm has the potential to accurately discriminate species with best overall accuracy. Knowledge on reduced key wavelength regions and spectral band combinations for successful discrimination of increaser species was obtained. These wavelengths were evaluated using the new WorldView imagery containing unique and strategically positioned band settings. The study demonstrated the potential of WorldView-2 bands in classifying grass at species level with an overall accuracy of 82% which is only 5% less than an overall accuracy achieved by AISA Eagle hyperspectral data. Overall, the study has demonstrated the potential of remote sensing techniques to classify different increaser species representing levels of rangeland degradation. In this regard, we expect that the results of this study can be used to support up-to-date monitoring system for sustainable rangeland management. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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Effects of sheep, kangaroos and rabbits on the regeneration of trees and shrubs in the chenopod shrublands, South AustraliaPalisetty, Raghunadh January 2007 (has links)
After European settlement, Australian rangelands especially in South Australia underwent significant changes because of the main land use of pastoralism. Many studies have revealed that the plant communities are negatively effected by herbivory mainly by sheep. The main aim of this study is to separate the different effects of sheep, rabbits and kangaroos. This was examined by survey supported by experimental and modelling research. A 32,000 km² area previously surveyed by Tiver and Andrew (1997) in eastern South Australia was re-surveyed to monitor populations of perennial plant species at sites of various intensity of grazing by sheep, rabbits and kangaroos (goats populations are low in the study area), the most important vertebrate herbivores. Plant population data were collected in both sheep paddocks and historically ungrazed by sheep (road reserves) by using the Random Walk method and analyzed using Generalized Linear Modelling (GLM) to separate the effects of sheep and rabbits on plant regeneration and their regeneration in response to grazing. These data were also compared to similar data collected by Tiver and Andrew in 1992 (1997) to ascertain if the reduction in rabbit numbers through introduction of RCV had allowed increased regeneration. Regeneration of many species inside paddocks were negatively affected and species in roadside reserves neither did not significantly increase from 1992 to 2004. However, some species showed increase of populations in spite of sheep grazing, with some species being less susceptible than others. This research also indicates kangaroo grazing impact on some plant species. Reduction in rabbit numbers following the 1995 release of calicivirus has not been effective in restoring regeneration. Another experiment was conducted at Middleback Field Station near Whyalla to identify herbivore grazing pressure on the arid zone plant species Acacia aneura using unfenced, sheep fenced and rabbit fenced grazing exclosures. This experiment was set up with seedlings in exclosures, ten replicates of each treatment, at plots four different distances from the watering point to identify the survivorship of seedlings. Data were collected by recording canopy volumes of seedling over an 18 month period and analyzed by Residual Maximal Likelihood (REML). Seedlings both near and far from the watering point were severely effected by large herbivores, either sheep, kangaroos or both, and in a separate experiment kangaroo grazing effects on the seedling were also identified. Seedlings browsed by the rabbits were recovered better than the seedlings grazed by the large herbivores. Decreasing kangaroo activities has been noticed when the rabbit movements increased. Computer modelling was conducted to predict the future plant population structure over 500 years using a matrix population model developed by Tiver et al. (2006) and using data collected in the survey as a starting point. Extinction probabilities of populations of Acacia aneura near watering points, far from watering points and under pulse grazing scenarios were compared. Sheep grazing was found to cause eventual extinction of populations in all parts of sheep paddocks. Together, the results indicate that sheep are the major herbivore suppressing regeneration of perennial plant species. Kangaroo and rabbits have an identifiable but lesser effect. The results have implications for conservation and pastoral management. To achieve ecological sustainability of arid lands a land-use system including a network of reserves ungrazed by sheep and with control of both rabbit and kangaroo numbers will be required.
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Influence of Soil Water Repellency on Post-fire Revegetation Success and Management Techniques to Improve Establishment of Desired SpeciesMadsen, Matthew D. 17 December 2009 (has links) (PDF)
The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that: • Post-fire patterns of soil WR were highly correlated to pre-fire P-J woodland canopy structure. Critical soil WR levels occurred under burned tree canopies while sub-critical WR extended out to approximately two times the canopy radius. At sites where critical soil WR was present, infiltration rate, soil moisture, and vegetation cover were significantly less than at non-hydrophobic sites. These parameters were also reduced in soils with subcritical WR relative to non-hydrophobic soils (albeit to a lesser extent). Aerial photography coupled with feature extraction software and geographic information systems (GIS) proved to be an effective tool for mapping P-J cover and density, and for scaling-up field surveys of soil WR to the fire boundary scale. • Soil WR impairs seed germination and seedling establishment by decreasing soil moisture availability by reducing infiltration, decreasing soil moisture storage capacity, and disconnecting soil surface layers from underlying moisture reserves. Consequently, soil WR appears to be acting as a temporal ecological threshold by impairing establishment of desired species within the first few years after a fire. • Wetting agents can significantly improve ecohydrologic properties required for plant growth by overcoming soil WR; thus, increasing the amount and duration of available water for seed germination and seedling establishment. Success of this technology appears to be the result of the wetting agent increasing soil moisture amount and availability by 1) improving soil infiltration and water holding capacity; and 2) allowing seedling roots to connect to underling soil moisture reserves.
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Plant Establishment and Soil Microenvironments in Utah Juniper Masticated WoodlandsYoung, Kert R. 05 July 2012 (has links) (PDF)
Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after a major increase in tree population density and associated decrease in perennial understory cover, there is a risk that invasive annual grasses will dominate because they are highly responsive to the increased resource availability that commonly follows removal of the main resource user. To determine if tree mastication increases resource availability and subsequently favors invasive annual or perennial grasses, we compared soil temperature, water, and nutrient microenvironmental conditions and seedling establishment and growth. We used the major rangeland weed, cheatgrass (Bromus tectorum L.), to represent invasive annual grasses and Anatone bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A. Löve), a natural accession of native bluebunch wheatgrass, to represent the perennial grasses of the sagebrush-bunchgrass plant community. These comparisons were made between and within paired-adjacent masticated and untreated areas at three locations in Utah dominated by Utah juniper (Juniperus osteosperma (Torr.) Little). Juniper tree mastication generally increased resource availability with masticated areas having greater soil temperature, soil water availability, and soil N supply rates than untreated areas. Prior to juniper tree mastication litter mounds were not found to be resource islands probably because juniper trees themselves were using subcanopy soil water and nutrients. After juniper tree mastication and elimination of these predominant resource users, litter mounds served as resource islands with greater soil water availability and N supply rates than bare interspaces during the critical time for seedling establishment in spring. Plant growth followed in line with greater resource availability after tree mastication with masticated areas having more productive although fewer invasive-annual and perennial grass seedlings than untreated areas. These results suggest that increases in resource availability and warmer spring temperatures associated with mastication will not necessarily favor invasive annual over perennial grass seedling establishment. Resilience of the sagebrush-bunchgrass community to return to dominance after juniper control will likely be greatly influenced by how much of the sagebrush-bunchgrass community remains following tree control and the intensity of propagule pressure by invasive species. If only invasive annuals remain when the trees are treated then invasive annuals would be expected to dominate the post-treatment plant community especially with their ability to establish inside litter mounds unless they were also controlled and perennial grasses planted at the time of treatment.
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Decentralization in the Kyrgyz agricultural sectorCrewett, Wibke 22 August 2016 (has links)
Seit der Unabhängigkeit der zentralasiatischen Republik Kirgisistan haben Politik, Verwaltung und Ökonomie verschiedene Formen von Dezentralisierung erfahren. Diese Dissertation umfasst fünf Essays, die die Dezentralisierung im landwirtschafltichen Sektor aus institutionenökonomischer Sicht untersuchen. Die ersten zwei Essays geben detaillierte Einblicke in die institutionellen Rahmenbedingungen von Dezentralisierung und beurteilen ihrer Wirkung in Hinblick auf Serviceverfügbarkeit und -qualität in dörflichen Gemeinden. Die folgenden drei Essays untersuchen, anhand einzelner und multipler Fallstudien, ein spezifisches Beispiel der Dezentralisierung landwirtschaftlicher Services: die Einführung von gemeindebasiertem Weidemanagement. Es lassen sich drei Ergebnisse ableiten: Erstens, internationale Nichtregierungsorganisationen (NROs) steuern das ländliche Dienstleistungsangebot und fördern die Bildung gemeindebasierter Nutzergruppen für ausgewählte Services. Zweitens, Institutionen zur Implementierung der Servicebereitstellung werden von NROs entwickelt; drittens, die Servicebereitsstellung ist nicht befriedigend und das Potential zur Berücksichtigung lokaler Servicebedürfnisse und lokalen Wissens wird nur teilweise ausgeschöpft, da die Implementierung keine umfassende Servicenutzerbeteiligung sicherstellt. Die Wirkungen gemeindebasierter Dezentralisierungsprozesse sind als Ergebnis rationaler Handlungsentscheidungen von lokalen Mitarbeitern der NRO und Verantwortlichen in der dörflichen Verwaltung zu verstehen. Diese Entscheidungen sind vielfach durch extern entwickelte, und teilweise unpassende, Institutionen bestimmt. Verbesserte Implementierungsstrategien sind daher notwendig. Diese sind auf Basis detaillierter qualitativer Studien des lokalen Umsetzungskontexts zu entwickeln. / Since the Central Asian Kyrgyz Republic gained independence from the Soviet Union, policy making, administration and economy have seen some form of decentralization. This dissertation contains five essays which study decentralization in the Kyrgyz agricultural sector from an institutional economics perspective. The first two essays provide in-depth information on the institutional setting of decentralization and its effects on service availability and quality at municipality level. The subsequent three essays explore, based on single and multiple case studies, one specific field of decentralized agricultural services: a community-based natural resource management reform in the pasture sector. The three key findings are: first, international NGOs govern rural service provision and support the creation of community-based service user groups for selected services; second, the NGOs design institutions for implementation and provide financial resources; third, service provision is unadequate and, because implementation does not provide for broader service user involvement in decision making, service user needs and local knowledge impact service decisions only to a very limited degree. The overall result of the dissertation is that the municipality-level processes of decentralization must be understood as outcomes of rational decision making of lowest-level NGO staff and municipality level policy administrators. These decisions are impacted by partly inappropriate, externally designed implementation institutions. Improved implementation rule design is therefore needed. The recommendation from this research is therefore to use detailed qualitative studies of implementation contexts as a basis for developing better tailored implementation strategies.
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To hunt and to hold : Martu Aboriginal people's uses and knowledge of their country, with implications for co-management in Karlamilyi (Rudall River) National Park and the Great Sandy Desert, Western AustraliaWalsh, Fiona Jane, January 2009 (has links)
[Truncated abstract] This ethnoecological study examines land uses by modern Martu Aboriginal people on their country. They occupy very remote settlementsParnngurr, Punmu and Kunawarritjiin the Great and Little Sandy Deserts. In 1990, their country included Crown Lands and Rudall River National Park. The study investigated the proposition that the knowledge and practices of Martu were of direct relevance to ecosystem processes and national park management. This research commenced in the wider Australian research context of the late 1980s early 90s when prevailing questions were about the role of customary harvest within contemporary Aboriginal society (Altman 1987; Devitt 1988) and the sustainability of species-specific harvests by Australian indigenous people (Bomford & Caughley 1996). Separately, there was a national line of enquiry into Aboriginal roles in natural resource and protected area management (Williams & Hunn 1986; Birckhead et al. 1992). The field work underpinning this study was done in 19861988 and quantitative data collected in 1990 whilst the researcher lived on Martu settlements. Ethnographic information was gathered from informal discussions, semi-structured interviews and participant observation on trips undertaken by Martu. A variety of parameters was recorded for each trip in 1990. On trips accompanied by the researcher, details on the plant and animal species collected were quantified. Martu knowledge and observations of Martu behaviour are interpreted in terms of the variety of land uses conducted and transport strategies including vehicle use; the significance of different species collected; socio-economic features of bush food collection; spatio-temporal patterns of foraging; and, the 'management' of species and lands by Martu. The research found that in 1990, hunting and gathering were major activities within the suite of land uses practiced by Martu. At least 40% of trips from the settlements were principally to hunt. More than 43 animal species and 37 plant food species were reported to be collected during the study; additionally, species were gathered for firewood, medicines and timber artefacts. Customary harvesting persisted because of the need for sustenance, particularly when there were low store supplies, as well as other reasons. The weight of bush meats hunted at least equalled and, occasionally, was three times greater than the weights of store meats available to Parnngurr residents. ... Paradoxically, hunting was a subject of significant difference despite it being the principal activity driving Martu expertise and practice. There is potential for comanagement in the National Park but it remains contingent on many factors between both Martu and DEC as well as external to them. The dissertation suggests practical strategies to enhance co-management.
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