Effect of pollinator abundance on self-fertilization and gene flow: application to GM Canola.

Cross-pollination from fields of transgenic crops is of great public concern. Although cross-pollination in commercial canola (Brassica napus) fields has been empirically measured, field trials are expensive and do not identify the causes of cross-pollination. Therefore, theoretical models can be valuable because they can provide estimates of cross-pollination at any given site and time. We present a general analytical model of field-to-field gene flow due to the following competing mechanisms: the wind, bees, and autonomous pollination. We parameterize the model for the particular case of field-to-field cross-pollination of genetically modified (GM) canola via the wind and via bumble bees (Bombus spp.) and honey bees (Apis mellifera). We make extensive use of the large data set of bee densities collected during the recent U.K. Farm Scale Evaluations. We predict that canola approaches almost full seed set without pollinators and that autonomous pollination is responsible for > or = 25% of seed set, irrespective of pollinator abundance. We do not predict the relative contribution of bees vs. the wind in landscape-scale gene flow in canola. However, under model assumptions, we predict that the maximum field-to-field gene flow due to bumble bees is 0.04% and 0.13% below the current EU limit for adventitious GM presence for winter- and spring-sown canola, respectively. We predict that gene flow due to bees is approximately 3.1 times higher at 20% compared to 100% male-fertility, and due to the wind, 1.3 times higher at 20% compared to 100% male-fertility, for both winter- and spring-sown canola. Bumble bee-mediated gene flow is approximately 2.7 times higher and wind-mediated gene flow approximately 1.7 times lower in spring-sown than in winter-sown canola, regardless of the degree of male-sterility. The model of cross-pollination due to the wind most closely predicted three previously published observations: field-to-field gene flow is low; gene flow increases with the proportion of plants that are male-sterile; and gene flow is higher in winter- than in spring-sown canola. Our results therefore suggest that the wind, not bees, is the main vector of long-distance gene flow in canola.     

Flipper beat frequency and amplitude changes in diving green turtles, <Emphasis Type="Italic">Chelonia mydas</Emphasis>

Using a turtle-borne camera system, changing flipper beat frequency and amplitude were measured in five diving green turtles (Chelonia mydas Linnaeus 1758) in the Bahía de los Angeles, Mexico (28°58′N, 113°33′W). These observations were made between June and August 2002. Turtles worked hardest (i.e., had the highest flipper beat frequency and amplitude) at the start of descents when positive buoyancy is predicted to oppose their forward motion. During the later part of descents, turtles worked less hard in line with opposing buoyancy forces being reduced. For example, flipper beat frequency declined from about 60–80 beats min⁻¹ at the start of descent to around 25–40 beats min⁻¹ after 30 s of the descent. At the start of ascents the flipper beat frequency was around 30 beats min⁻¹, lower than on descent, and declined as the ascent progressed with often passive gliding for the final few meters to the surface. This pattern of effort during diving appears to apply across a range of marine reptiles, birds and mammals suggesting that graded effort during descent and ascent is an optimum solution to minimising the cost of transport during diving.     

针对优选药物的水质指南导引

药物会进入淡水系统并影响水生态系统的健康。即使广泛应用的药物已经过毒性检测,以证据为基础的水质标准依然没有制定出。将BurrIII型分布应用于慢性毒性数据的物种敏感度分布(SSD),我们得到了卡马西平、双氯芬酸、氟西汀和美托洛尔4种药物在淡水中高度可靠的水质标准指引值(GV)。数据经过质检并且符合慢性无观察效应浓度(NOEC)或是10%有效浓度(即影响到10%的物种)要求,其终点与种群相关,效应指标为发育、生长、生殖与存活状况。由于生物标记物的回应(例如生化、组织及分子回应)与野生种群相关的影响并不存在直接的联系,故得出的相关数据并未考虑在内。在保护95%物种的范围内,得出卡马西平、双氯芬酸、氟西汀和美托洛尔4种药物的GV分别为4.3,770,1.6和14 μg?L^L-1。广泛应用在欧盟委员会、瑞士与德国的GV则是基于有限数据库中最敏感的实验终点 (可能包括生化、组织及分子生物标记物的回应)。本实验得出的GV显著高于这些可靠性未知的GV。
精选自Anupama Kumar, Graeme E. Batley, Bhanu Nidumolu, Thomas H. Hutchinson. Derivation of water quality guidelines for priority pharmaceuticals. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1815–1824, July 2016. DOI: 10.1002/etc.3336
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3336/full
     

A foundation for developing a methodology for social network sampling

Researchers are increasingly turning to network theory to understand the social nature of animal populations. We present a computational framework that is the first step in a series of works that will allow us to develop a quantitative methodology of social network sampling to aid ecologists in their social network data collection. To develop our methodology, we need to be able to generate networks from which to sample. Ideally, we need to perform a systematic study of sampling protocols on different known network structures, as network structure might affect the robustness of any particular sampling methodology. Thus, we present a computational tool for generating network structures that have user-defined distributions for network properties and for key measures of interest to ecologists. The user defines the values of these measures and the tool will generate appropriate network randomizations with those properties. This tool will be used as a framework for developing a sampling methodology, although we do not present a full methodology here. We describe the method used by the tool, demonstrate its effectiveness, and discuss how the tool can now be utilized. We provide a proof-of-concept example (using the assortativity measure) of how such networks can be used, along with a simulated egocentric sampling regime, to test the level of equivalence of the sampled network to the actual network. This contribution is part of the special issue “Social Networks: new perspectives” (Guest Editors: J. Krause, D. Lusseau and R. James).     

Organochlorine and trace metal residues in adult southern bent-wing bat (Miniopterus schreibersii bassanii) in southeastern Australia

In recent times, the apparent population decline of the southern bent-wing bat (Miniopterus schreibersii bassanii) at Bat Cave, Naracoorte has been ascribed to pesticide use in the region, following the finding of organochlorine and orgaonophosphate insecticide residues in bat guano. Adult southern bent-wing bats were collected from Bat Cave and Starlight Cave in 2003. Organochlorine contaminants were detected in all carcass samples: p,p'-DDE was by far the most dominant contaminant with concentrations ranging from 11,000 to 59,000ngg(-1), followed by p,p'-DDT (110-1600ngg(-1)), p,p'-DDD (35-620ngg(-1)), summation operatorPCBs (33-490ngg(-1)), summation operatorchlordane and related compounds (7.9-270ngg(-1)), HCB (1.6-120ngg(-1)), HP epox. (3.1-230ngg(-1)), TCPMOH (3.8-38ngg(-1)), summation operatorHCHs (1.4-9.6ngg(-1)), and TCPMe (0.1-4.2ngg(-1)) (all values on lipid-weight basis). No significant difference in DDE, DDD, DDT, summation operatorDDT, summation operatorPCB, trans-chlordane, heptachlor epoxide, trans-nonachlor, alpha-HCH, beta-HCH, gamma-HCH, TCPMOH or TCPMe concentrations were observed either between sexes within sites, or between sites (p>0.05). However, there were significant differences in HCB and oxychlordane concentrations between sexes and between sites (p<0.05), between site differences in cis-nonachlor concentrations in male bats (p<0.05), and cis-chlordane concentrations between sexes at Starlight Cave, and between males of each site (p<0.05). There were also significant differences in the liver concentrations of some metals between sexes within sites (Ag, Cd, Co, Cu, Pb, Se, Zn), and between sites (Ag, Cd, Co, Cu, Hg, Pb, Se, V, Zn). Clustering or grouping of sites was observed when the OC data was expressed on a lipid-weight basis. These inter-site differences in OC concentrations reflect local exposure over a period of time, and do not unambiguously support any suggestion that we are witnessing incipient speciation. However, for conservation purposes, it may be prudent to assume that there are two sub-populations of M. s. bassani feeding in different locations in this region of southern Australia, rather than the single homogeneous population suggested by genetic studies.     

Environmental fate of pesticides used in Australian viticulture III. Fate of dithianon from vine to wine

Pinot noir, bastardo, rkaziteli and semillon grapes on vines grown in the Barossa Valley of South Australia were treated with a commercial dithianon formulation. The grapes were harvested by hand eight days later, and made into wine. Grab samples of berries, grape juice and the young wine were analysed for fungicide residues. No dithianon was detected in control grape samples, grape juices or wines. Significant dithianon levels were detected on the skins of treated grape samples. Dithianon is stable on the surface of grapes under the ambient conditions prevalent under the grape canopy for at least two weeks. No dithianon was detected in grape juice, on grape skins after berry crushing, in the lees, or in the young wine. Dithianon is unstable in grape juice and wine. Dithianon half‐life (initial concentration = 1 μg/mL) in semillon grape juice = 2.8 h, semillon wine = 0.58 h, pinot noir grape juice = 4.6 h, and pinot‐noir wine = 0.29 h. Treatment with fining agents or heat does not significantly reduce the rate of degradation. These results suggest that spraying table grapes with dithianon two weeks before harvest would result in exposure to essentially the full dose of active ingredient sprayed, and increase the risk to human health through ingestion of this compound. However, any threat to human health from ingestion through grape juice or wine is limited since any contact with grape juice or wine leads to rapid decomposition of dithianon by some as yet undetermined process.     

Effect of selenium on the growth of Lemna minor

The effect of selenium on the vegetative reproduction of cultured Lemna minor was investigated. Cultures were grown for 28 days at a temperature of 23 ± 3°C and under a constant (24 h) light cycle. Growth was monitored every seven days. The growth of L. minor was inhibited at high concentrations (>5mg/L [Se]), but stimulated at low concentrations (0.2—2mg/L [Se]). This stimulation of growth at low selenium concentrations has significant implications for the use of selenium enriched superphosphate fertilisers on selenium deficient pastures.     

Influence of Social, Biophysical, and Managerial Conditions on Tourism Experiences Within the Great Barrier Reef World Heritage Area

N  = 1475) traveling with tourism operations of different sizes who traveled to different sites completed surveys. Results indicated that snorkelers who traveled with larger operations (more people and infrastructure) differed from those traveling with smaller operations (few people and little on-site infrastructure) on benefits received and in the way that specific conditions influenced their enjoyment. Benefits related to nature, escape, and family helped to define reef experiences. Conditions related to coral, fish, and operator staff had a positive influence on the enjoyment of most visitors but, number of people on the trip and site infrastructure may have the greatest potential as setting indicators. Data support the potential usefulness of visitor input in applying the LAC concept to a marine environment where tourism and recreational uses are rapidly changing.