Relationships between aquatic invertebrate communities,water-level fluctuations and different habitats in a subtropical lake

In lakes, the littoral habitat and its invertebrate communities are often exposed to water-level fluctuations. We examined the effects of seasonal changes on water level, substrata availability and benthic fauna in the littoral zone of Peri Lake, a shallow lake that has experienced a strong reduction in water level due to changes in rainfall. In this study, we also examined whether the abundance and composition of aquatic invertebrates differed among the four substrata. Our main objective was to assess the effect of seasonal changes on water level and benthic invertebrates inhabiting the different types of substrata. Benthic invertebrates were sampled four different substrata (Schoenoplectus californicus, sand and stones, allochthonous leaf litter, and macrophyte stands), and we also measured meteorological, physical and chemical variables. We found that complex habitats, such as allochthonous leaf litter and aquatic macrophyte, stand to be colonised by a larger number of macroinvertebrates because they provide more habitats or potential niches for colonisation by different species. In addition, we observed that during periods of low water level, the presence of substrata in the littoral zone decreased, as did the associated biota. Therefore, our results suggest that water level changes have a major functional impact on the littoral zone of the lake, and can affect substratum availability, which also impacts invertebrate communities.     

A climate-change vulnerability and adaptation assessment for Brazil's protected areas

Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km²) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km²), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.     

Larvicidal and pupicidal activities of eco-friendly phenolic lipid products from Anacardium occidentale nutshell against arbovirus vectors

Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of...     

Invasion of Pinus halepensis Mill. following a wildfire in an Argentine grassland nature reserve

The Ernesto Tornquist nature reserve is a relict of native Pampas vegetation in Argentina. Alien trees were introduced to the reserve in the 1950s, mainly to "improve" the natural landscape, resulting in the arrival of a totally new life form. In 1987, a fire affected an area planted with Pinus halepensis resulting in its massive expansion. In 1999, we removed trees from 17 circular plots of 10 m diameter placed systematically within the area that was colonized after the fire. Trunks were cut 20 cm from the ground and growth rings were counted. We studied the age structure of the population in order to reconstruct the colonizing events after the fire. We found that recruitment occurred throughout this period, except in the three years after the disturbance. We suggest that this delay in recruitment might be caused by low seedling survival under water stress conditions due to low rainfall, combined with scarce vegetation cover after fire. This could have been associated with an initial reduction in propagule pressure due to the scarcity of surviving trees in the vicinity and with the fact that fire occurred after the peak of seed release, during an extremely dry summer, probably killing a great number of seeds that were already in the soil. In the following years, recruitment was probably aided by pioneer trees and later by seeds shed from established pines. Alien trees had been allowed to reach maturity due to wildfire prevention and control in the years preceding the fire and the accumulated dry matter resulted in increased fire intensity that reduced the ability of grasses to re-sprout. As a consequence, the invasion window that allowed the expansion of pines remained open for at least 12 years.     

Soil subsampling in environmental sciences: the role of granulometry

Uncertainty associated to analytical results is an issue of major interest for the whole analytical community. A large effort has been made to improve analytical techniques and procedures aimed to achieve a well characterized uncertainty associated with analysis. However, it is becoming increasingly recognised that uncertainty deriving from sampling and subsampling can even dominate the global uncertainty budget. A study on subsampling activities on different soil typologies has been performed by granulometry determinations. The differences between sieving methodologies based on both wet and dry mode have been studied. Subsampling is approached by replicated measurements providing a quantitative assessment of the distribution heterogeneity, a suitable method validation scheme and an empirical determination of uncertainty.     

Asparagus ploidy distribution related to climates adaptation in Iran

Environment, Development and Sustainability - Asparagus basic chromosome number is 2n?=?2x?=?20. The high rate of polyploidy in wild asparagus has been found in natural...     

Discrete event simulation to aid decision-making and mitigation in solid waste management

This article aims to evaluate municipal solid waste (MSW) management schemes in order to promote sustainability and eco-efficiency, core elements in global mitigation strategies in both public and private policies. A discrete event simulation (DES) approach was used to integrate the economic, environmental, and social aspects related to aseptic carton packages (ACP) in Itajuba, Brazil. The simulated scenarios consider three alternatives for disposing ACP: landfills, recycling, and incineration with energy recovery. According to our findings, incineration alternatives are preferred from an eco-efficiency perspective, given the potential greenhouse gas (GHG) emissions reductions and due to the possibility of energy recover, which reinforces the contribution of this technology to promote sustainability as largely found in the international literature. Given the context of MSW management in Brazil, this represents a significant opportunity to increase the effectiveness of mitigation strategies adopted in the country. Taking into account that this is by far the least applied technology, the authors strongly advocate that global strategies for mitigation consider different approaches to integrate carbon dioxide (CO₂) emission reductions related to the entire MSW management system and its alternatives, thus advancing from a waste disposal-oriented system to a life cycle–oriented system.

     

Carbon Emissions Trading and Equity in International Agreements

This paper explores the distributional consequences of alternative emissions trading schemes. It is argued that the distributional impact stems from the difference between two social welfare functions: the function which is implicitly maximised in a competitive market equilibrium and the function which is implicitly adopted when a given equity principle is chosen. An integrated assessment model is used to illustrate these findings, by simulating the introduction of various emissions trading schemes for the Kyoto protocol on the reduction of greenhouse emissions. It is shown that (1) changes produced on an equity index by the imposition of emission constraints (by country) may not be significantly higher than those obtained by the subsequent introduction of a market mechanism, and that (2) the various market regimes which could be adopted have quite different distributional implications. This revised version was published online in July 2006 with corrections to the Cover Date.     

Application of the benthic index of biotic integrity to environmental monitoring in Chesapeake Bay

The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River, Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay.