Ecological restoration as a strategy for conserving biological diversity

Though the restoration of disturbed ecosystems has so far played a relatively modest role in the effort to conserve biological diversity, there are reasons to suspect that its role will increase and that its contribution to the maintenance of diversity will ultimately prove crucial as techniques are further refined and as pristine areas for preservation become scarcer and more expensive.It is now possible to restore a number of North American communities with some confidence. However, it should be noted that many current efforts to return degraded lands to productive use, like attempts to reclaim land disturbed by mining, try only for rehabilitation to a socially acceptable condition and fall considerably short of actually restoring a native ecological community.Possible uses for restoration in the conservation of biodiversity include not only the creation of habitat on derelict sites, but also techniques for enlarging and redesigning existing reserves. Restoration may even make it possible to move reserves entirely in response to long-term events, such as changes in climate. Restoration in the form of reintroduction of single species to preexisting or restored habitat is also a critical link in programs to conserve species ex situ in the expectation of eventually returning them to the wild. And restoration provides opportunities to increase diversity through activities as diverse as management of utility corridors, transportation rights-of-way, and parks.     

Evaluating the sampling pattern when detecting Zones of Abrupt Change

We present a method for detecting the zones where an irregularly sampled variable changes abruptly in the plane. Such zones are called Zones of Abrupt Change (ZACs). This method not only allows estimation of ZACs, but also testing of their statistical significance against the null hypothesis of a stationary correlated random field. The sampling pattern, in particular its local density, is crucial in the detection of potential ZACs. In this paper, we address the problem of evaluating the sampling pattern by assessing the power of the local test used for detecting ZACs. It is shown that mapping the power allows us to identify zones where ZACs may or may not be detected. The methodology is applied to a soil data set sampled at eight different dates in an agricultural field. Detecting ZACs for the soil water content allowed us to identify permanent structures in the agricultural field related to the boundaries between different soil types. Mapping the power for various sampling densities proved to be useful to determine the minimal sampling density necessary for detecting ZACs.

An ecological approach to environmental impact assessment

Carbon cycling analysis is presented as a means for assessing anthropogenic perturbations in an ecosystem. Data from oligotrophic, eutrophic, and dystrophic (bog) lakes are used to show general trends in the lacustrine carbon cycle. The oligotrophic lake is an unstressed system and the eutrophic lake is under nutrient enrichment with high algal standing crops and productivity. The bog lake is a pH-stressed environment that is primarily a grazing ecosystem. It is hoped that a more effective environmental impact assessment will result from the use of carbon cycling as a unifying concept in ecosystem analysis.     

Human exposure to PCBs, PBDEs and HBCDs in Ghana: Temporal variation, sources of exposure and estimation of daily intakes by infants

Human exposure to polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) was evaluated in Ghana using breast milk samples collected in 2004 and 2009. Mean levels and ranges of PBDEs (4.5; 0.86-18 ng/g lw) and PCBs (62; 15-160 ng/g lw) observed in the present study were unexpectedly high, in spite of the fact that Ghana is a non-industrialized country when compared with many of the Asian and European countries. Significant increases were found in the concentrations of PCBs and PBDEs over the years, while no significant increase was observed for HBCDs. Estimated hazard quotient (HQ) showed that all the mothers had HQ values exceeding the threshold of 1 for PCBs, indicating potential health risk for their children. PCBs in dirty oils and obsolete equipment should be of concern as potential sources in Ghana, and e-waste recycling with little or no experience in safe handling could be a threat to this sub-region noted for unregulated disposal of e-waste. The results may point towards an increase in trends in human milk in Ghana, especially in the larger cities but further analysis would be required to confirm this upward trend in levels. This is the first study to report BFRs in human breast milk from Africa, and undoubtedly from Ghana.     

Air quality monitoring system using lichens as bioindicators in Central Argentina

Air quality studies with bioindicators have not been well developed in South America. In the city of Córdoba, there are not permanent air pollutant measurements by equipment. In order to develop an air quality biomonitoring system using lichens, we applied a systematic sampling in the city of Córdoba, Argentina. A total of 341 plots were sampled in the area of the city which is a square of 24 × 24 km. In each sample plot we selected three phorophytes and estimated the frequency and cover of lichen species growing at 1.5 m on trunks. We also calculated the Index of Atmospheric Purity (IAP) using lichen frequencies. Maps with number of lichen species, cover values, and IAP were performed. The lichen community was described with nine species where Physcia undulata and Physcia endochryscea were the most frequent. Moreover, these two species were dominant in the community with the highest cover index. The central area of the city is considered a lichen desert with poor air quality. The southeast and northwest areas of the city showed the highest IAP values and number of species. In general, the city shows fair air quality and few areas with good and very good air quality.     

Growing Sustainable Peace: Student solutions for a sustainable future

Abstract

The charge of Local Agenda 21 is to facilitate agency by a wide range of actors in civil society. Student groups, both in schools and universities, have the potential to be important agents. This commentary concerns one example of student agency addressing sustainable development in a highly politicized context where political and social justice are high on the public agenda. On 14 April 2005 three students from the London School of Economics hosted a conference in Jerusalem for Palestinian and Israel students. This was one of the first joint conferences of Palestinians and Israelis since the start of the second Intifada in 2000. The subject of the conference was sustainable development in the Middle Eastern context and the following is an article composed by some of the conference participants. Their views are presented in their own words in order to recognize their ownership of the process. The authors suggest that projects that create a collaborative forum for Palestinians and Israelis regardless of the subject create a setting for track-three diplomacy and an opportunity to deconstruct stereotypes and learn from one another's knowledge. ‘Track-three’ diplomacy is understood in this article as grassroots initiatives implemented by ‘amateurs’ which feed into more official diplomatic relations. Further details on this project are available at <http://www.growingpeace.org>.