16 research outputs found
Preventing the spread of Faxonius limosus in Trentino: management challenges, experimental protocols and new threats
No full textTwo Alien Invasive crayfish species are present in Trentino (NE Italy): Procambarus clarkii and Faxonius limosus. Both species were accidentally introduced in the first decade of this century with fish restocking; their introduction caused the extinction of populations of the native Austropotamobius pallipes. Procambarus clarkii was so far recorded only in one small lake at 950 m asl, whereas Faxionus limosus has colonized a group of 5 lakes at 450 m asl, over an area of about 80km2. The containment of Faxionus limosus is therefore difficult, given its presence in a high number of lakes, three of which are hydrologically connected. The first containment campaign to prevent its spread was conducted in summer 2023 in the downstream-most of the three connected lakes, Costa Lake, a small lake of about 1 hectare surface area. The efficiency of traps with different mesh size was tested in a 10-day campaign in mid-June, a more extensive one-week campaign was conducted in July. The use of small size (1 cm) mesh was the most efficient trapping system, as the small body size of the individuals probably allows them to escape from the standard, larger size (3x2 cm) mesh; crayfish were collected mainly in the canal which acts as the emissary of the lake, connecting it to the main river network. Unexpectedly and unluckily, individuals of Procambarus clarkii were collected in the NW part of the lake, suggesting a recent, point introduction, of unknown origin, which represent a further threat for the area
Feasibility of fisheries co-management in Africa
No full textThe current, highly centralized approach to fisheries management seems to be incapable of coping with escalating resource depletion and environmental degradation. Co-management has been identified as an alternative. This paper compares various approaches to fisheries management and discusses their performance in relation to the nature of the fishery. It is concluded that in African fisheries, stringent institutional arrangements, poor human, technical and financial resources, and a limited time frame often thwart co-management approaches. However, with the right conditions and prerequisites, comanagement can be successful in improving compliance with regulations and maintaining or enhancing the quality of the resource. The paper brings out the issues that require further research.Fishery management, Community involvement, Fishery regulations, Sociological aspects, Africa,
The effect of land restitution on protected areas : an analysis of the co-management model in operation at the Mkambati Nature Reserve
No full textIncludes bibliographical references.With the advent of the Constitution of the Republic of South Africa, and having been faced with a huge number of land claims on protected areas, the South African Government adopted a co-management system as a way of informing the settlement of land claims lodged within protected areas. Through a case study of the Mkambati Nature Reserve (MNR) in the Eastern Cape, this dissertation seeks to critically analyse the co-management conservation model that is in operation in the MNR, in order to provide a proper perspective on whether it provides a satisfactory model for reconciling both the country’s protected area regime and its land reform regime. The dissertation commences with a brief analysis of South Africa’s socioeconomic and environmental realities, in order to contextualise the analysis. It then turns to consider South Africa’s constitutional framework, and, particularly, the environmental right and the property clause, which have largely been responsible for shaping and informing South Africa’s contemporary conservation and land reform regime. Thereafter, it seeks to briefly outline these two relevant regimes, with a view to critically analysing the manner in which they complement, or do not complement, one another. It then critically reviews recent initiatives taken by the country’s conservation and land reform authorities to bridge the apparent divide between South Africa’s protected areas and land reform regimes. These initiatives include both a Memorandum of Understanding, signed by the erstwhile Minister of Land Affairs and the Minister of Environmental Affairs and Tourism, and the recent National Co-Management Framework adopted by these authorities. Thereafter, the dissertation turns to critically reflect on the effectiveness and equitability of the co-management model advocated by these initiatives, through the lens of a case study – namely, the MNR in the Eastern Cape. This section of the dissertation starts by providing a background to the reserve, and the history form and nature of the settlement agreement implemented to resolve the land restitution claim within it. It then turns to the evaluation of the governance regime that is in operation in the MNR (specifically in respect of its land tenure, management, access/use and benefit-sharing arrangement), with a view to drawing lessons which could possibly inform the resolution of the many outstanding land restitution claims in protected areas
Characteristics, main impacts, and stewardship of natural and artificial freshwater environments: Consequences for biodiversity conservation
No full textIn this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime-periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems)
Wildlife Conservation and Management in Kenya: Towards a Co-management Approach
No full textThe co-management approach of managing natural resources has increasingly become popular among conservationists and development practitioners since it overcomes the shortcomings of both the centralised management and community-based approaches that hinder harmonization of conflicting interests among diverse stakeholder groups. Considering criteria developed from theoretical advancements on co-management and drawing on empirical studies conducted in Kenya, the paper examines how successful the co-management approach has been in terms of meeting the needs and interests of local communities and conservationists. Further, it analyses some of the factors or conditions that contribute towards the emergence and subsequent adoption of the co-management approach in the conservation and management of wildlife. These factors, which may also be important in other developing countries, include the provision of a favourable policy framework, institutional capacity of organized user groups to co-manage wildlife resources, land tenure conditions and accessibility to wildlife resources. It is emphasised that the co-management approach has had, so far, mixed results and there are certain important factors challenging its successful implementation in Kenya.Kenya, Co-management, Wildlife management, Conditions for co-management, Sustainable management
Bridging the gap between conservation and land reform : communally-conserved areas as a tool for managing South Africa's natural commons
No full textIncludes abstract.Includes bibliographical references (p. 370-417).This dissertation examines whether the concept of communally-conserved areas provides a useful tool for bridging the current apparent impasse between South Africa’s conservation and land reform agendas
Stream diatom biodiversity in islands and continents : a global perspective on effects of area, isolation and environment
No full textAbstract: Aim The species-area relationship (SAR) is one of the most distinctive biogeographic patterns, but global comparisons of the SARs between island and mainland are lacking for microbial taxa. Here, we explore whether the form of the SAR and the drivers of species richness, including area, environmental heterogeneity, climate and physico-chemistry, differ between islands and similarly sized areas on mainland, referred to as continental area equivalents (CAEs). Location Global. Taxon Stream benthic diatoms. Methods We generated CAEs on six continental datasets and examined the SARs of CAEs and islands (ISAR). Then, we compared CAEs and islands in terms of total richness and richness of different ecological guilds. We tested the factors contributing to richness in islands and CAEs with regressions. We used structural equation models to determine the effects of area versus environmental heterogeneity, climate and local conditions on species richness. Results We found a non-significant ISAR, but a significant positive SAR in CAEs. Richness in islands was related to productivity. Richness in CAEs was mainly dependent on area and climate, but not directly on environmental heterogeneity. Species richness within guilds exhibited inconsistent relationships with island isolation and area. Main conclusions Ecological and evolutionary processes shaping diatom island biogeography do not depend on area at the worldwide scale probably due to the presence of distinct species pool across islands. Conversely, area was an important driver of diatom richness in continents, and this effect could be attributed to dispersal. Continents had greater richness than islands, but this was a consequence of differences in environmental conditions such as specific island climatic conditions. We stress the need for more island data on benthic diatoms, particularly from archipelagos, to better understand the biogeography of this most speciose group of algae
A global comparison of stream diatom beta diversity on islands versus continents across scales
No full textAbstract: Aim: To evaluate the patterns of stream diatom beta diversity in islands versus continents across scales, to relate community similarities with spatial and environmental distances and to investigate the role of island characteristics in shaping insular diatom beta diversity. Location: Africa, America, Europe and the Pacific. Time Period: Present. Major Taxa Studied: Stream diatoms. Methods: We compared diatom beta diversity between islands and continents at large scales (within biogeographic regions) in two study regions (America and Europe) and at small scales (within islands/equivalent areas in continents) in three regions (Africa, America and Europe) partitioning beta diversity into turnover and nestedness components. We used a partial Mantel test and distance-decay curves to assess how diatom beta diversity on islands and continents is affected by spatial and environmental distances. Finally, using island data from all four regions, we evaluated the relationship between island beta diversity and island latitude, area, age and isolation using linear models. Results: At large scales, mean dissimilarities were higher on islands than in continents in Europe but lower in America. At smaller scales, the differences varied mostly depending on island isolation. Beta diversity was mainly caused by species turnover. Partial Mantel test and distance-decay curves revealed that spatial and environmental distances shaped diatom beta diversity at large, but not at small scales. Moreover, diatom beta diversity on islands was affected by island latitude, age and isolation, but not by island area. Main Conclusions: Diatom beta diversity on islands versus continents and its responses to spatial and environmental factors are scale and region dependent. Incomplete colonisation, evolutionary processes and environmental filtering likely contribute to insular beta diversity, which further varies with island latitude, age and isolation. This study sheds new light on beta diversity of microorganisms on islands and suggests that beta diversity should be explicitly considered in island biogeographical research
Stream diatom worldwide dataset and environmental data
No full textThis dataset include the data used in the paper entitle "Stream diatom biodiversity in islands and continents – a global perspective on the effects of area, isolation and the environment" published in 2022 in Journal of Biogeography.
This dataset is a RData format which include 2 objects: 'comm_tot' and 'env'.
'comm_tot'includes presence-absence of diatom species (Omnidia code) of 5446 sites from 18 islands (Co: Corsica, Cy: Cyprus, Gu: Guadeloupe, Ic: Iceland, Ir: Ireland, Ka: Kauai, Re: La Réunion, Ma: Martinique, Md: Madeira, Mj: Majorca, My: Mayotte, Nc: New Caledonia, Nz: North New Zealand, Oa: Oahu, Po: Possession, Sm: São Miguel, Sa: Sardinia and Sz: South New Zealand) and six continental areas (Ch: China, Fi: Finland, Fr: France, Gy: French Guiana, Ke: Kenya and Us: USA).
'env' includes environmental data associated with each sampling station, including geographical coordinates ('x' and 'y'), pH, conductivity ('cond' in uS/cm), total phosphorus ('tp' in mg/l), total nitrogen ('tn' in mg/l), orthophosphates ('po4' in mg/l), water temperature (wat_temp in °C), bioclimatic data from WorldClim database at 0.5 minutes resolution ('ann_prec': annual precipitation (mm), 'prec_sea': seasonality in precipitation (%), 'ann_temp': annual temperature (°C), and 'sea_temp': temperature seasonality), altitude ('alti' in meters) and slope.
The data from Mayotte island reported in this dataset comes from Rimet, F., Tapolczai, K., Vasselon, V., Mary, N. & Bouchez, A. (2019) Mayotte rivers: databases used for the development of diatom and macroinvertebrates water quality tools. https://doi.org/10.15454/6Z5IA
Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation
No full textIn this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems).Forestry, Faculty ofNon UBCForest and Conservation Sciences, Department ofReviewedFacult
