38 research outputs found
Підвищення інвестиційної привабливості підприємств житлово-комунального господарства України на основі використання закордонного досвіду
Мета роботи - підвищення інвестиційної привабливості підприємств житлово-комунального господарства на основі можливостей використання закордонного досвіду реформування
Human disruption of coral reef trophic structure
The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass distribution among trophic levels may be disrupted through trophic replacement by alternative organisms in the ecosystem, trophic cascades, and humans preferentially impacting specific trophic levels [4, 5 and 6]. Using empirical data spanning >250 coral reefs, we show how trophic pyramid shape varies given human-mediated gradients along two orders of magnitude in reef fish biomass. Mean trophic level of the assemblage increased modestly with decreasing biomass, contrary to predictions of fishing down the food web [7]. The mean trophic level pattern is explained by trophic replacement of herbivorous fish by sea urchins at low biomass and the accumulation of slow-growing, large-bodied, herbivorous fish at high biomass. Further, at high biomass, particularly where fishers are not selectively removing higher trophic level individuals, a concave trophic distribution emerges. The concave trophic distribution implies a more direct link between lower and upper trophic levels, which may confer greater energy efficiency. This trophic distribution emerges when community biomass exceeds ∼650 kg/ha, suggesting that fisheries for upper trophic level species will only be supported under lightly fished scenarios
Recommended from our members
Nudging fisheries and aquaculture research towards food systems
Food system is a powerful concept for understanding and responding to nutrition and sustainability challenges. Food systems integrate social, economic, environmental and health aspects of food production through to consumption. Aquatic foods are an essential part of food systems providing an accessible source of nutrition for millions of people. Yet, it is unclear to what degree research across diverse disciplines concerning aquatic foods has engaged food systems, and the value this concept has added. We conducted a systematic review of fisheries, aquaculture and aquatic food literature (2017–2019) to determine the following: the characteristics of this research; the food systems components and interrelations with which research engaged; and the insights generated on nutrition, justice, sustainability and climate change. Sixty five of the 88 reviewed articles focussed on production and supply chains, with 23 considering human nutrition. Only 13% of studies examined low- and middle-income countries that are most vulnerable to undernutrition. One third of articles looked beyond finfish to other aquatic foods, which illuminated values of local knowledge systems and diverse foods for nutrition. When aggregated, reviewed articles examined the full range of food system drivers—biophysical and environmental (34%), demographic (24%) and socio-cultural (27%)—but rarely examined interactions between drivers. Future research that examines a diversity of species in diets, system-wide flows of nutrients, trade-offs amongst objectives, and the nutritional needs of vulnerable social groups would be nudging closer to the ambitions of the food systems concept, which is necessary to address the global challenges of equity, nutrition and sustainability
Helminth fauna of the Siberian chipmunk, Tamias sibiricus Laxmann (Rodentia, Sciuridae) introduced in suburban French forests
International audienceThe spread of an immigrant host species can be influenced both by its specific helminth parasites that come along with it and by newly acquired infections from native fauna. The Siberian chipmunk, Tamias sibiricus Laxmann (Rodentia, Sciuridae), a northeastern Eurasiatic ground nesting Sciurid, has been introduced in France for less than three decades. Thirty individuals were collected from three suburban forests in the Ile-de-France Region between 2002 and 2006. Two intestinal nematode species dominated the helminth fauna: Brevistriata skrjabini [Prevalence, P, 99% C.I., 87% (64–97%); mean intensity, M.I., 99% C.I., 43 (28–78)] and Aonchotheca annulosa [P, 47% (25–69%); M.I., 35 (3–157)]. B. skrjabini is a direct life cycle nematode species of North Eurasiatic origin, with a restricted spectrum of phylogenetically related suitable hosts. This result indicates that B. skrjabini successfully settled and spread with founder pet chipmunks maintained in captivity and released in natura. Chipmunks acquired A. annulosa, a nematode species with a large spectrum of phylogenetically unrelated suitable host species, from local Muroid rodent species with similar behavior, life-history traits and habitats. Quantitative studies are needed to evaluate the potential for both B. skrjabini and A. annulosa to impede the spread of Tamias and for B. skrjabini to favor chipmunk colonization through detrimental effects upon native co-inhabiting host species
Scenario modelling to support industry strategic planning and decision making
The Pastoral Properties Futures Simulator (PPFS) is a dynamic systems model, developed within a participatory action research partnership with the pastoral industry of Australia's Northern Territory. The model was purpose-built to support the industry's strategic planning capacity in the face of environmental, market and institutional uncertainty. The mediated modelling process sought to maximise social learning of industry stakeholders. Simulations were conducted using scenarios representing combinations of climatic, market, institutional and technological assumptions. Stochastic parameters included rainfall and product prices. Economic and environmental performance of model farms, including greenhouse gas emissions, were estimated. A critical evaluation of the tool finds the PPFS fit for purpose. However, limitations include lack of output validation, small number of scenarios and simplistic treatment of environmental impact dimensions. With further development, the PPFS can provide a platform (a) to assist with industry planning across the whole of Northern Australia and beyond, and (b) for policy analysis and development in the context of the Australian pastoral industry
Winners and losers in marine conservation: fishers' displacement and livelihood benefits from marine reserves
Marine reserves can create both benefits and costs to fishers. This article explores the perceptions of fishers in Kenya and Seychelles about displacement, spillover, and overall impacts of local marine reserves on their livelihoods. We test whether these perceptions are different among fishers from different geographic and socioeconomic conditions. Sixty-six percent of fishers had been displaced from marine reserves or coastal development and 90% believed they had caught fishes that spilled over from marine reserves. Poorer fishers in Kenya were both displaced from, and also felt like they benefited from, marine reserves. This highlights how people's experiences with marine reserves, both positive and negative, are affected by a range of social considerations that may not be incorporated in typical evaluations of ecological and economic marine reserve success
Appendix D. Summary of generalized linear models (GLM) of reef area and isolation as a function of longitude and latitude.
Summary of generalized linear models (GLM) of reef area and isolation as a function of longitude and latitude
Appendix A. Species observed by underwater visual census on the Great Barrier Reef, Australia.
Species observed by underwater visual census on the Great Barrier Reef, Australia