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Cathryn Clarke Murray Thomas W. Therriault Evgeny Pakhomov 《Environmental management》2013,52(2):374-384
Despite an increased understanding of marine invasions, non-indigenous species (NIS) continue to be redistributed at both global and regional scales. Since prevention is an important element of NIS programs, monitoring vectors responsible for NIS introductions and spread, such as hull fouling, has become a priority and methods should be selected carefully to balance accuracy, time, and cost. Two common fouling assessment tools for the marine recreational boating vector were evaluated for accuracy using a traditional underwater SCUBA survey in coastal British Columbia: a dockside level of fouling assessment and a behavioral questionnaire model. Results showed that although rapid, dockside assessments did not provide an accurate assessment of fouling present below the surface, at least not in this region. In contrast, a questionnaire-based model using four easily obtained variables (boat type, age of antifouling paint, storage type, and occurrence of long distance trips) reliably identified boats carrying macrofouling species, a proxy for risk of NIS transport. Once validated, this fouling model tool could be applied in border inspection or quarantine situations where decisions must be made quickly. Further development and refinement of rapid assessment tools would improve our ability to prevent new introductions and manage spread of existing invasive species. 相似文献
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During R.R.S. Discovery Cruise 100 in the Southern Ocean (1979), 620 specimens of the Antarctic cranchiid squid Galiteuthis glacialis (Chun) were caught in the RMT8 opening-closing net, to the south of the Antarctic Polar Front (APF). The catch was dominated by individuals <20 mm dorsal mantle length (DML) and, apart from two specimens, the rest of the catch was <60 mm DML. Two larger squid (255 mm DML) were both immature and apparently female. The species is concentrated at a depth of 300 to 400 m; there is evidence of ontogenetic spreading and a shift in the modal depth of the population from the 300 to 400 m horizon in daylight to the 200 to 300 m horizon in darkness. The collection confirms the circumpolar distribution of the species and supports previous evidence that it rarely, if ever, occurs to the north of the APF. As in Mesonychoteuthis hamiltoni, the only other species of cranchiid squid known to occur south of the APF, the early-life phase of G. glacialis is concentrated in the upper zone of the warm deep water beneath the Antarctic surface layer where, putatively, there is a zone of enhanced biological activity. 相似文献
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Esther Clarke Ulrich H. Reichard Klaus Zuberbühler 《Behavioral ecology and sociobiology》2012,66(1):85-96
Predation on gibbons is rarely observed in the wild. However, the gibbons' moderate body size and relatively small social
groups suggest high vulnerability to predation. To assess the role of predation and to study their anti-predator behaviour,
we presented visual predator models to nine groups of wild white-handed gibbons at Khao Yai National Park, Thailand. We measured
subjects' immediate and delayed responses to four potential predators: tiger, clouded leopard, crested serpent eagle and reticulated
python. Subjects reliably approached all four predators. In response to tigers and leopards, they additionally produced predator-specific
songs and defecated copiously. In terms of delayed responses, distance between mated adults decreased, but only after exposure
to the tiger model. In response to eagles and pythons, gibbons consistently vocalised, but this did not always include predator
singing, and we found no long-term effects in overall activity or strata use. However, during 6 of 26 predator encounters,
the gibbons produced songs with a structure that was intermediate between a duet song and a predator song more than 20 min
after the predator encounter, indicating a long-term effect on their vocal behaviour. This study demonstrates that gibbons
discriminate between different potential predators and respond to them with adaptive anti-predator behaviour, which include
predator-specific vocal responses. We conclude that gibbons are not immune to predation and that terrestrial predators elicit
consistent immediate and delayed anti-predation responses. 相似文献
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The atomised nature of the humanitarian system has led to frequent and repeated attempts to coordinate humanitarian activity. Since 2005, some of the best resourced, and arguably most successful, coordination mechanisms have been the humanitarian Clusters, groups of UN (United Nations) and non‐UN actors that engage in sectoral coordination of humanitarian response (such as the provision of healthcare and water) at the global and country level. Nevertheless, it is not clear exactly what ‘coordination’ means in the context of a Cluster. Formal guidance suggests that they should be aiming to create a single, joint strategy to guide the activities of members. Actual experience of the Clusters, however, indicates that looser forms of coordination are more effective. This finding resonates with organisational theory, and with the experience of emergency management professionals beyond the international humanitarian sector. To capitalise fully on the success of the Clusters, policymakers may need to rethink their attitudes to, and expectations of, coordination. 相似文献
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Dune slack habitats are highly dependent on the availability of water to support flora and fauna. Typically this is provided
by shallow groundwater. This paper describes the seasonal and long term variation in groundwater levels in part of the Sefton
coastline between 1972 and 2007. The effects of climate change, vegetation management and coastline realignment on groundwater
levels are modelled. The observed annual water table levels rise and fall with an amplitude of 1.5 m, but longer term variations
and trends are apparent. A stochastic water balance model was used to describe the changes in water table levels in slack
floors in the open dunes and also in areas afforested with pine trees. It was found that the pine trees evaporated 214 mm/year
more than open dunes vegetation, resulting in the water table being 0.5–1.0 m lower under the trees than under the open dunes.
The effects of climate change on the ground water was simulated using predictions of future climate conditions based on the
UKCIP02 medium high emissions scenario. The increase in temperature and change in rainfall patterns will result in a decrease
in mean ground water levels by 1.0–1.5 mm in the next 90 years. Typical patterns consist of sequences of 5–10 years of low
water table levels interspersed by infrequent sequences consisting of 2–5 years of relatively high or “normal” levels. These
results indicate that that flora and fauna that cannot survive a 5–10 year period of water table levels >2.5 m below ground
level are unlikely to survive or persist in many slack areas and a change in the ecology of these slack may become inevitable.
Other effects of climate change include sea level rise which will result in a gradual rise in water table levels. Coastal
erosion will increase the water table gradient to the sea and result in a slight lowering of the ground water levels. Conversely
coastal accretion will reverse this process. The spatial distribution of coastal erosion and accretion along the Sefton coastline
and its likely impacts on groundwater levels are discussed. The modelling work described in this paper has identified the
factors which have the largest effect on groundwater levels in temperate coastal dune systems. 相似文献
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