Comparison of allozyme and mitochondrial DNA spatial differentiation in the limpet Patella vulgata

Allozyme and restriction enzyme analysis of mtDNA was used to study variation in samples from British populations of the marine limpet Patella vulgata in two regions. South Wales and Northeast England. Allozyme analysis revealed significant differences in allele frequencies among samples. However F _ST (population differentiation) values were no higher between than within regions, indicating that genetic heterogeneity was localised and not related to geographic separation. For mtDNA, samples from South Wales exhibited higher haplotype diversity values than samples from Northeast England. In addition there were substantial differences in the haplotype distribution between regions. The value of , the haploid analogoue of F _ST , was low within regions (=0.09) but high between regions (=0.44). The estimated difference in migration rate for allozymes and mtDNA exceed the neutral expectation, unless it is assumed that there are influential differences in the magnitude of female and male gametic dispersal.     

Monitoring of Bt-Maize pollen exposure in the vicinity of the nature reserve Ruhlsdorfer Bruch in northeast Germany 2007 to 2008

Background, aim, and scope Basically, technological innovations are associated with benefits and risks. This is also true for the introduction of genetically modified organisms (GMO) into agriculture. In Germany, precautionary regulations currently demand isolation distances (i.?e. buffer zones) for the cultivation of genetically modified maize (Bt-maize) in the vicinity of conventional (150?m) and organic maize fields (300?m). The Bt-toxin may harm non-target organisms (NTO) such as Lepidoptera. Despite this, corresponding regulations for the protection of nature reserves are lacking to date. Conventional and Bt-maize have been grown in the vicinity of the Flora-Fauna-Habitat (FFH) Ruhlsdorfer Bruch in Brandenburg, Germany. The aim of this study was to investigate whether exposure of maize pollen from surrounding Bt-maize fields to NTOs in the nature protection area could be excluded or not. Two types of exposure were investigated: Firstly, whether maize pollen was dispersed by wind into the nature reserve area exposing resident NTOs. Secondly, foraging NTOs from the nature reserve are exposed by roaming the surrounding fields and collecting maize pollen. In order to fulfil the precautionary principle defined by law, the study should help to determine appropriate isolation distances for the cultivation of Bt-maize with regard to sustainable protection of NTOs in the FFH Ruhlsdorfer Bruch. In 2007, the local authorities issued an isolation distance between Bt-maize fields and nature reserves of 100?m and in 2008, this became 250?m in the northern and 500?m in the westerly direction, respectively. Materials and methods Standardised methods for biological and technical pollen sampling issued by the Association of German Engineers (VDI 4330 Part 3, 2007 and VDI 4330 Part 4, 2006) were applied providing a quality controlled and methodologically harmonised database which does not only serve the needs to be fulfilled by the present case-specific monitoring study but can also be used as a reference database for further investigations. Maize pollen exposure was measured within the FFH Ruhlsdorfer Bruch and its immediate vicinity in July and August 2007 and 2008. In 2007, the sampling was performed at three sites using 12 technical samplers (Sigma-2/PMF) placed at five measuring points at distances from 5?m to 120?m from the maize field edges. Additionally, for biological pollen sampling six bee colonies were situated at these three sites (two colonies at each site). The technical sampler Sigma-2/PMF enables point sampling which is primarily influenced by wind and topography providing information on effective maize pollen input (flow and deposition) at the measuring sites. Honey-bees roaming in the surrounding area with typical foraging distances of several kilometres may act as planar collectors. They may serve as indicators for the exposure to pollen-collecting NTOs. Furthermore, biological sampling is more selective due to the organism’s preferences, whereas the technical sampling is neutral. Hence, both the technical and the biological sampling complement each other in their scope of application. The pollen samples of both matrices were analysed microscopically and the maize pollen loads were quantified. Pollen-DNA was analysed by means of the quantitative PCR-method (qPCR) identifying conventional and Bt-maize pollen by two independent laboratories. In 2008, the monitoring was repeated with additional sites. Eighteen technical samplers were exposed at five sites with eight measuring points at distances from 5?m to 250?m from the maize field edges. Two honey-bee colonies for biological sampling were placed at one site for control purposes. PCR-analyses were performed to measure the amounts of Bt-maize pollen in the samples. Results The results of pollen monitoring at the Ruhlsdorfer Bruch revealed maize pollen exposure for all monitoring sites in both surveys. In 2007, up to 1.75 million maize pollen/m² were deposited at sites closest to the maize field. At 120?m from field edge in the middle of the FFH-reserve, 99,000 maize pollen/m² were detected. In 2008, similar results were found, at distances up to 250?m from the field edges deposition of 164,000 maize pollen/m² was detected. Data on maize pollen deposition show a clear distance relationship and are in accordance with results of further comprehensive surveys based on the same methodology (Hofmann 2007). The results of the microscopic analysis of the pollen pellets demonstrated that bees collected maize pollen at all sites, in 2007 and 2008. Although maize pollen is not the main food source (2007:0.1–0.3?%; 2008:2–3?%) the collection efficiency of the bee colonies resulted in high amounts of sampled maize pollen with 4 to 11 million per site in 2007 and up to 467 million in 2008. Molecular-biological analysis of maize pollen DNA by qPCR demonstrated that transgenic Bt-MON810 DNA was present in all technical and biological samples, corroborated by two independent laboratories. In 2007, the GMO-content in the samples ranged up to 44?% in the bioaerosols and 49?% in the pollen pellets. In 2008, GMO-proportions of up to 18?% were detected. Discussion The results of this study provide evidence that NTOs in the Ruhlsdorfer Bruch were exposed to Bt-maize pollen under the cultivation conditions in 2007 with a buffer zone of 100?m. The GMO-content reached up to 48?%. The results of the monitoring in 2008 confirmed these findings. Even though the exposure could be reduced by increasing the isolation distances to 250?m and 500?m respectively, the results still show percentages of up to 18?% Bt-MON810 in the pollen samples. The results on maize pollen deposition at the Ruhlsdorfer Bruch in 2007 and 2008 correspond to the results of an investigation which was conducted over several years applying the same standardised method, but covering a wider range of distances. The correlation between maize pollen deposition (n/m²) and distance to the source field (m) fitted best to a power function of the type y = 1.2086 · 10⁶ · x ^–0.548. Despite the same trend, the pollen deposition in the Ruhlsdorfer Bruch revealed above-average findings. Also the analysis of the pollen pellets collected by the bees showed an exposure in 2007 with values for the GMO-content of up to 49?%. For both methods, the exposure decreased in 2008 due to the greater buffer zones up to 500?m. Whereas the GMO-content for the biological sampling were reduced to values below 10?%, the values for the technical sampling were still higher indicating that greater buffer zones would be necessary for safety reasons under the precautionary principle. Conclusions The results of this investigation proved that maize pollen were dispersed by wind to distances farther than 250?m from field edge leading to maize pollen exposure in the centre of the nature reserve. The results also demonstrated that foraging NTOs living in the nature reserve were exposed to maize pollen from surrounding fields. Considering the cultivation of Bt-maize MON810, the assumption of the Environmental Risk Assessment (ERA) that there will be no relevant exposure beyond the Bt-maize fields, cannot be confirmed. Considering the results of this and related studies and with respect to the precautionary principle, one can state that buffer zones between Bt-maize fields and protected areas are an effective measure to minimise the exposure of Bt-maize pollen to NTOs and, thus, to prevent from adverse effects. Recommendations and perspectives Because of still insufficient ecotoxicological data for the risk assessment of Bt-maize MON810 considering butterflies and other protected NTOs, protection standards assuring the precautionary principle have to be implemented to avoid Bt-maize pollen exposure to NTOs. This applies for the case Ruhlsdorfer Bruch and for nature reserve areas in general. In order to exclude risks to protected NTOs occurring in nature reserves, sufficient buffer zones for Bt-maize cultivation should be considered. The statistical analysis revealed that distances of more than 500?m are necessary to decisively reduce exposure to foraging insects. In fact, distances of more than 1,000?m are necessary to prevent maize pollen deposition from values above 100,000 pollen/m² with a certainty of 90?%. An adequate risk assessment can only be attained if based on field measurements accounting for the high variation of pollen deposition due to local environmental site conditions and field management. The monitoring should be based on standardised methods. It should include locations with the highest expected deposition rates, the boundaries of the protected areas and sites of interest within those boundaries, e.?g., specific habitats of sensitive species.     

Understanding the Lessons and Limitations of Conservation and Development

Abstract: The lack of concrete instances in which conservation and development have been successfully merged has strengthened arguments for strict exclusionist conservation policies. Research has focused more on social cooperation and conflict of different management regimes and less on how these factors actually affect the natural environments they seek to conserve. Consequently, it is still unknown which strategies yield better conservation outcomes? We conducted a meta‐analysis of 116 published case studies on common resource management regimes from Africa, south and central America, and southern and Southeast Asia. Using ranked sociodemographic, political, and ecological data, we analyzed the effect of land tenure, population size, social heterogeneity, as well as internally devised resource‐management rules and regulations (institutions) on conservation outcome. Although land tenure, population size, and social heterogeneity did not significantly affect conservation outcome, institutions were positively associated with better conservation outcomes. There was also a significant interaction effect between population size and institutions, which implies complex relationships between population size and conservation outcome. Our results suggest that communities managing a common resource can play a significant role in conservation and that institutions lead to management regimes with lower environmental impacts.     

Genetic amniocentesis in biamniotic twin pregnancies by a single transabdominal insertion of the needle

We present a technique to aspirate amniotic fluid from both sacs in biamniotic twin pregnancies using a single abdominal insertion with a spinal needle. It was successful in 48 out of 55 cases of biamniotic twin pregnancies referred to our perinatal unit between 1985 and 1994. The single insertion technique was used when the inter-amniotic membrane was clearly evident and two separate free amniotic fluid pools could be reached by the operator with a single puncture. An adequate amount of amniotic fluid was sampled from both sacs to make a cytogenetic diagnosis in all cases. There were four fetuses with trisomy 21 in three twin pregnancies. In two cases, only one twin was affected whilst the co-twin was normal, so that a selective feticide was performed. No miscarriages due to genetic amniocentesis were reported. After 1990, all genetic amniocenteses in biamniotic twin pregnancies (except for one case due to late booking) were performed between 14 and 15 weeks of gestation and with all cases except one, it was possible to sample both twins by a single puncture. We suggest that early amniocentesis (14–15 weeks) by a single abdominal puncture could be a reliable and safe alternative to first-trimester chorionic villus sampling in twin pregnancies.     

A coastal cliff management district for protection of eroding high relief coasts

Ensuring that new buildings do not interfere with the recreational and protective functions of the natural system and that the buildings will be useful long enough to protect the investment are among long-term solutions to coastal erosion. We propose that coastal cliff management districts be established for management of eroding high relief shorelines. Such districts would include an imminent failure zone, in which bluff retreat is possible at any time; a migration zone, which allows for long-term shoreline retreat; and a stability control zone in which activities affecting bluff erosion are restricted. Procedures are described for delineating these zones based on geomorphic criteria. If these land use controls are implemented, some shorefront development can be accommodated while retaining valuable characteristics of the natural system.