Search

Freshwater ecosystems provide a large number of benefits to society. However, extensive human activities threat the viability of these ecosystems, their habitats, and their dynamics and interactions. One of the main risks facing these systems is the overexploitation of groundwater resources that hinders the survival of several freshwater habitats. In this paper, we study optimal groundwater paths when considering freshwater ecosystems. We contribute to existing groundwater literature by including the possibility of regime shifts in freshwater ecosystems into a groundwater management problem. The health of the freshwater habitat, which depends on the groundwater level, presents a switch in its status that occurs when a critical water level ('tipping point') is reached. Our results highlight important differences in optimal extraction paths and optimal groundwater levels compared with traditional models. The outcomes suggest that optimal groundwater withdrawals are non-linear and depend on the critical threshold and the ecosystem's health function. Our results show that the inclusion of regime shifts in water management calls for a reformulation of water policies to incorporate the structure of ecosystems and their interactions with the habitat. [ABSTRACT FROM AUTHOR]

Human liver fluke, Opisthorchis viverrini , a food-borne trematode is a significant public health problem in Southeast Asia, particularly in Thailand. Despite a long history of control programmes in Thailand and a nationwide reduction, O. viverrini infection prevalence remains high in the northeastern provinces. Therefore, a new strategy for controlling the liver fluke infection using the EcoHealth/One Health approach was introduced into the Lawa Lake area in Khon Kaen province where the liver fluke is endemic. A programme has been carried using anthelminthic treatment, novel intensive health education methods both in the communities and in schools, ecosystem monitoring and active community participation. As a result, the infection rate in the more than 10 villages surrounding the lake has declined to approximate one third of the average of 50% as estimated by a baseline survey. Strikingly, the Cyprinoid fish species in the lake, which are the intermediate host, now showed less than 1% prevalence compared to a maximum of 70% at baseline. This liver fluke control programme, named “Lawa model,” is now recognised nationally and internationally, and being expanding to other parts of Thailand and neighbouring Mekong countries. Challenges to O. viverrini disease control, and lessons learned in developing an integrative control programme using a community-based, ecosystem approach, and scaling-up regionally based on Lawa as a model are described. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After the USSR's disintegration, many rivers received international status. This provided the basis for developing a reliable mechanism of regulation of relations between the states on transboundary river exploitation. Three basic problems associated with the example of transboundary rivers of Russia and Kazakhstan are: the unsatisfactory ecological state of international rivers; the necessity of changing the priorities concerning protection and resource conservation of water; the basin approach based on integrated water resource management of the whole international rivers basin as a unified ecosystem. For the basin management system to be improved in Russia, it is important to study the international experience and the Canadian one, in particular. [ABSTRACT FROM AUTHOR]

Aims: The main aim of this study was to assess the prevalence of various health outcomes associated with exposure to environmental risk factors including industrial pollution in selected communities of Nigeria's oil-rich Niger delta area (NDA). Methods: The study involved both laboratory experiments and community health surveys using questionnaires and hospital records. A total of 14 air samples, 16 grab soil samples and 18 surface water samples were collected and analyzed for physicochemical parameters including heavy metals and polycyclic aromatic hydrocarbons (PAHs) using standard methods. A 77-item questionnaire was administered on randomly selected 349 subjects. A five-year record was collected from health facilities located in the two communities. Results: The laboratory results indicated that the median PAH level at Eleme as compared to Ahoada East was higher than the guideline limit 50 ng/l for surface waters. The mean TSP level at Eleme was higher than the level at Ahoada East and the guideline limit 100 µg/m³. The median PAH level at Eleme was higher than the level at Ahoada East and the guideline limit < 100 ng/m³ for air. The survey results showed that at Eleme air pollution in the community was significantly associated with painful body outgrowths (p = 0.027) and the effect the air contaminants has was significantly associated with respiratory health problem (p = 0.044). At Ahoada East commonly consumed aquatic food was highly significantly associated with painful body outgrowth (p < 0.0001) while use of domestic cooking fuel types was also highly significantly associated with child deformities (p < 0.0001). Hospital records showed high proportions of respiratory disorder among males (3.85%) and females (4.39%) at Eleme as compared to the proportion of respiratory disorder among males (3.68%) and females (4.18%) at Ahoada East. Conclusions: The study shows that industrial communities such as Eleme, which are exposed to higher levels of air pollution, are more predisposed to respiratory morbidities, skin disorders and other related health risks. [ABSTRACT FROM AUTHOR]

Over the last 30 years, the Cerrado has been experiencing various antropic impacts that have brought about alterations to species composition, structure and functioning of aquatic habitats. Therefore, studies on negative impacts are useful to prevent future damage and restore environmental quality. The objectives of our study were: i) to adapt an index of biotic integrity of streams in the Rio Cuiabá Basin and ii) to analyze if the Index of Biotic Integrity (IBI) correlated with the environmental quality measured by the Index of Environmental Quality (IEQ) and with the mesohabitat structure. We sampled 26 streams in sub-basins of the Cuiabá River. In each stream, we closed a stretch of 50 m with blockage nets and used electrofishing to capture fish. To obtain a measure of environmental quality in sampled units, we characterized the stream and its micro basin. For the analyses, we used the Spearman Correlation, Kruskal-Wallis test and Analysis of Multiple Regression. We collected 697 individuals distributed into 6 orders, 15 families and 49 species. The IBI followed changes on environmental quality measured by IEQ when we removed streams that present natural barriers from the analysis (r² = 0.4; r² = 0.58). Types of land use did not affect the biotic integrity (n = 26; df = 4; H = 4,860; p = 0.302), but natural and artificial barriers affected it (n = 26; df = 4; H = 11,027; p = 0.026). The IBI was not sensitive to variations in mesohabitat structure (F2,23 = 0.373; r² = 0.031; Axe 1 p = 0.620; Axe 2 p = 0.490). The IBI is certainly a reasonable instrument for evaluating changes in the environment, but we cannot ignore the fact that we were able to obtain the same result with any combinations of metrics. This makes its analysis and interpretation difficult.