Can dispersal mode predict corridor effects on plant parasites?

Habitat corridors, a common management strategy for increasing connectivity in fragmented landscapes, have experimentally validated positive influences on species movement and diversity. However, long-standing concerns that corridors could negatively impact native species by spreading antagonists, such as disease, remain largely untested. Using a large-scale, replicated experiment, we evaluated whether corridors increase the incidence of plant parasites. We found that corridor impacts varied with parasite dispersal mode. Connectivity provided by corridors increased incidence of biotically dispersed parasites (galls on Solidago odora) but not of abiotically dispersed parasites (foliar fungi on S. odora and three Lespedeza spp.). Both biotically and abiotically dispersed parasites responded to edge effects, but the direction of responses varied across species. Although our results require additional tests for generality to other species and landscapes, they suggest that, when establishing conservation corridors, managers should focus on mitigating two potential negative effects: the indirect effects of narrow corridors in creating edges and direct effects of corridors in enhancing connectivity of biotically dispersed parasites.     

Edge effects, not connectivity, determine the incidence and development of a foliar fungal plant disease

Using a model plant-pathogen system in a large-scale habitat corridor experiment, we found that corridors do not facilitate the movement of wind-dispersed plant pathogens, that connectivity of patches does not enhance levels of foliar fungal plant disease, and that edge effects are the key drivers of plant disease dynamics. Increased spread of infectious disease is often cited as a potential negative effect of habitat corridors used in conservation, but the impacts of corridors on pathogen movement have never been tested empirically. Using sweet corn (Zea mays) and southern corn leaf blight (Cochliobolus heterostrophus) as a model plant-pathogen system, we tested the impacts of connectivity and habitat fragmentation on pathogen movement and disease development at the Savannah River Site, South Carolina, USA. Over time, less edgy patches had higher proportions of diseased plants, and distance of host plants to habitat edges was the greatest determinant of disease development. Variation in average daytime temperatures provided a possible mechanism for these disease patterns. Our results show that worries over the potentially harmful effects of conservation corridors on disease dynamics are misplaced, and that, in a conservation context, many diseases can be better managed by mitigating edge effects.     

Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin,Brazilian equatorial margin

Environmental Science and Pollution Research - The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through...     

Biochemical profile of non-enzymatic stress markers in the plant species “<Emphasis Type="Italic">Urginea maritima</Emphasis>” in a Mediterranean natural reserve exposed to oxidative stress

Protected areas decrease degrading natural ecosystems due to pollution such as air pollution. In 1981, the inhabitants founded Bentael natural reserve in Byblos, Lebanon, to secure their region against urbanization projects, like the recently constructed road that threatens the biodiversity of the reserve. This study was conducted to determine the oxidative stress resulting from this pollution and that menaces 360 floral species among them a rare species “Urginea maritima.” In this research, the biomonitoring approach was experienced to assess the oxidative stress. Biomonitoring possesses has the advantage to be low cost and a constructive method to generate valuable data for further examinations. The studied parameters were air pollutants, ascorbic acid, photosynthetic pigments, leave’s pH, relative water content, proline, carbohydrates, and hydrogen peroxide, in three chosen spots, near the pollution source (P1), opposite the latter spot (P2), and in an area relatively far from the source of contamination and which was chosen as the control site (Ctrl). The results showed in P1 detection of air pollutants higher of about 80% than in Ctrl, modifications in stress markers: increased concentration of the reactive oxygen species “hydrogen peroxide,” rise in the concentration of the osmoregulator amino acid “proline,” and depletion in chlorophyll content, in contrast to an increase in pheophytin. All these findings can be exploited as early diagnosis of air pollution and confirmed the ability to use such biomonitor (“Urginea maritima”) as a way to assess the environmental pollution levels and consequently affirm the danger of such landscape activities on natural reserves.     

The determination of trace metal pollutants in environmental matrices using ion chromatography

A review is presented detailing the development of ion chromatography (IC) as a selective analytical tool for the determination of toxic metals and their organic species in many environmental sample matrices. A brief outline of ion chromatographic principles, together with an overview of the stationary phases used to separate metals, namely ion exchangers, modified ion pair sorbents and chelating ion exchangers, and the methods for detecting metal ions including hyphenation with spectroscopy and sample preparation schemes are also given, prior to a critical examination of developed methods for various metals including arsenic, chromium, cadmium, lead, mercury, beryllium, aluminium and uranium since 1990.