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A Multi-Scale Investigation of Factors Limiting Bull Trout ViabilityBowerman, Tracy 01 May 2013 (has links)
Effective conservation strategies for imperiled species require an understanding of processes that influence fitness throughout the organism's life cycle and across the range of habitats needed to complete that cycle. I evaluated factors that affect population viability of bull trout Salvelinus confluentus, a threatened freshwater char species, throughout individual life stages and over the entire life cycle. I assessed the relationship between bull trout egg incubation success and environmental variables. Egg survival was negatively related to the percent of fine sediment in redds and positively related to hydraulic conductivity and the strength of downwelling. Next, I quantified juvenile bull trout survival rates and described movement patterns for this life stage. Juvenile bull trout emigrated from natal headwaters into larger rivers throughout the entire year and across a range of sizes. Estimates of juvenile survival rates improved dramatically when emigration was incorporated into the analysis. I integrated my observations of bull trout survival, growth, and movement to create a life-cycle model, which I used to better understand how populations respond to changes in specific demographic rates. Bull trout populations were particularly sensitive to changes in juvenile growth and survival. The relative effect of changes to fertility rates and adult survival varied depending upon whether a population was composed primarily of large, migratory, or smaller, resident individuals. Dispersal helped to lower the probability of extinction for small or declining populations when neighboring populations were stable. My research demonstrates that bull trout require access to habitats throughout entire watersheds to maintain population viability. My results suggest that limiting anthropogenic sources of fine sediment and maintaining areas of channel complexity that promote downwelling can be important for bull trout embryo survival. Management decisions should also consider the diverse behavior of juvenile bull trout and the wide range of habitat they use. Additionally, connectivity between populations is likely to be important for declining populations to persist. The diversity of life-history strategies expressed by bull trout helps maintain demographic stability within and among populations. As such, preservation of habitat integrity and full life-history diversity is imperative for conservation and recovery of bull trout populations range-wide.
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A Multi-Scale Investigation of Factors Limiting Bull Trout ViabilityBowerman, Tracy 01 May 2013 (has links)
Effective conservation strategies for imperiled species require an understanding of processes that influence fitness throughout the organism's life cycle and across the range of habitats needed to complete that cycle. I evaluated factors that affect population viability of bull trout Salvelinus confluentus, a threatened freshwater char species, throughout individual life stages and over the entire life cycle. I assessed the relationship between bull trout egg incubation success and environmental variables. Egg survival was negatively related to the percent of fine sediment in redds and positively related to hydraulic conductivity and the strength of downwelling. Next, I quantified juvenile bull trout survival rates and described movement patterns for this life stage. Juvenile bull trout emigrated from natal headwaters into larger rivers throughout the entire year and across a range of sizes. Estimates of juvenile survival rates improved dramatically when emigration was incorporated into the analysis. I integrated my observations of bull trout survival, growth, and movement to create a life-cycle model, which I used to better understand how populations respond to changes in specific demographic rates. Bull trout populations were particularly sensitive to changes in juvenile growth and survival. The relative effect of changes to fertility rates and adult survival varied depending upon whether a population was composed primarily of large, migratory, or smaller, resident individuals. Dispersal helped to lower the probability of extinction for small or declining populations when neighboring populations were stable. My research demonstrates that bull trout require access to habitats throughout entire watersheds to maintain population viability. My results suggest that limiting anthropogenic sources of fine sediment and maintaining areas of channel complexity that promote downwelling can be important for bull trout embryo survival. Management decisions should also consider the diverse behavior of juvenile bull trout and the wide range of habitat they use. Additionally, connectivity between populations is likely to be important for declining populations to persist. The diversity of life-history strategies expressed by bull trout helps maintain demographic stability within and among populations. As such, preservation of habitat integrity and full life-history diversity is imperative for conservation and recovery of bull trout populations range-wide.
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The identification and verification of optimal reintroduction sites for the Southern Ground Hornbill Bucorvus leadbeateri in the Musina area of the Limpopo Province, South Africa / Francette Jerling.Jerling, Francette January 2011 (has links)
The Southern Ground Hornbill (SGH) (Bucorvus leadbeateri) has recently been listed globally by the IUCN Red list as Endangered or Critically Endangered. In South Africa, the declining population of the SGH has led it to be listed nationally as Vulnerable and falls under the “Protected Species” legislation. Research into the habitat preferences and identification of suitable reintroduction areas have been few since the initiation of reintroduction attempts, therefore resulting in mixed outcomes of previously-reintroduced SGH. The aim of this study was to identify and verify optimal reintroduction sites for the SGH, in the Musina area in the Limpopo Province. Five main objectives were determined, namely: to identify optimal reintroduction areas; to develop a habitat profile of the designated area; to determine the availability of prey items; to determine the availability of large trees needed for nesting and roosting; to evaluate pre-release sites by involving a number of stakeholders. Three study sites were selected on the farm Greyghost Safaris (Ludwigslust), each made up of a different plant community. Sampling was carried out a total of four times during the year: one sampling bout in each season. A niche-based modelling technique was used to describe the suitability of a particular habitat (“ecological space”) then used to project it onto another geographical space. Floristic and faunal surveys were conducted to determine the species composition of prey items and composition and frequency of the herbaceous and woody layer. High-resolution, natural-colour aerial imagery was used in order to determine the availability of trees for nesting and roosting. Pre-release site evaluations and stakeholder engagements were conducted by means of interviews with landowners on and around the study sites. The Limpopo River Valley and across to the KNP on the eastern border of the Limpopo Province, is suitable re-introduction sites for the SGH. This study site provided a good opportunity to explore what an optimal site for reintroduction should resemble. / Thesis (MSc (Zoology))--North-West University, Potchefstroom Campus, 2012.
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The identification and verification of optimal reintroduction sites for the Southern Ground Hornbill Bucorvus leadbeateri in the Musina area of the Limpopo Province, South Africa / Francette Jerling.Jerling, Francette January 2011 (has links)
The Southern Ground Hornbill (SGH) (Bucorvus leadbeateri) has recently been listed globally by the IUCN Red list as Endangered or Critically Endangered. In South Africa, the declining population of the SGH has led it to be listed nationally as Vulnerable and falls under the “Protected Species” legislation. Research into the habitat preferences and identification of suitable reintroduction areas have been few since the initiation of reintroduction attempts, therefore resulting in mixed outcomes of previously-reintroduced SGH. The aim of this study was to identify and verify optimal reintroduction sites for the SGH, in the Musina area in the Limpopo Province. Five main objectives were determined, namely: to identify optimal reintroduction areas; to develop a habitat profile of the designated area; to determine the availability of prey items; to determine the availability of large trees needed for nesting and roosting; to evaluate pre-release sites by involving a number of stakeholders. Three study sites were selected on the farm Greyghost Safaris (Ludwigslust), each made up of a different plant community. Sampling was carried out a total of four times during the year: one sampling bout in each season. A niche-based modelling technique was used to describe the suitability of a particular habitat (“ecological space”) then used to project it onto another geographical space. Floristic and faunal surveys were conducted to determine the species composition of prey items and composition and frequency of the herbaceous and woody layer. High-resolution, natural-colour aerial imagery was used in order to determine the availability of trees for nesting and roosting. Pre-release site evaluations and stakeholder engagements were conducted by means of interviews with landowners on and around the study sites. The Limpopo River Valley and across to the KNP on the eastern border of the Limpopo Province, is suitable re-introduction sites for the SGH. This study site provided a good opportunity to explore what an optimal site for reintroduction should resemble. / Thesis (MSc (Zoology))--North-West University, Potchefstroom Campus, 2012.
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The Austerical City. : London at the crush test of austerity / Den Austeriska Staden. : Londons austerity-krocktest.Aquili, Tommaso January 2018 (has links)
In the UK, the unprecedented cuts to local budgets, implemented by the national governments from 2010 to the present day, have pushed local authorities to reconsider their scope, their role and their action. The ever decreasing budgets have de facto transformed local councils from service providers to territorial entrepreneurs, as the pressing pursuit of revenues has placed the economic profit at the core of the local policy-making. Urban planning plays a central role in this shift in mindset. The British planning system has been remodelled so to facilitate the implementation of development processes, as these grant revenues from planning obligations, uplifts in land values and higher income from taxes. The reform of the planning system has however conceded free rein to developers, especially through the introduction of the Development Viability Appraisal, a document which they use to reduce the provision of affordable housing, in favour of luxury housing tenures. Therefore, in London the mechanisms that rule the territorial transformations exacerbate the existing housing crisis and force local communities to face displacement. Austerity has thus initiated a cascade-effect whose negative externalities are tangible at the very local level. The emerged topics find their concretization in the description of the Heygate Estate regeneration.
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