Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management

Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems

Stroke radiology and distinguishing characteristics of intracranial atherosclerotic disease in native south asian pakistanis

Background: There are no descriptions of stroke mechanisms from intracranial atherosclerotic disease in native South Asian Pakistanis. Methods: Men and women aged ≥ 18 years with acute stroke presenting to four tertiary care hospitals in Karachi, Pakistan were screened using magnetic resonance angiography/transcranial Doppler scans. Trial of ORG 10172 in Acute Stroke Treatment criteria were applied to identify strokes from intracranial atherosclerotic disease. Results: We studied 245 patients with acute stroke due to intracranial atherosclerotic disease. Two hundred thirty scans were reviewed. Also, 206/230 (89.0%) showed acute ischaemia. The most frequent presentation was with cortically based strokes in 42.2% (87/206) followed by border-zone infarcts (52/206, 25.2%). Increasing degrees of stenosis correlated with the development of both cortical and border-zone strokes (P = 0.002). Important associated findings were frequent atrophy (166/230, 72.2%), silent brain infarcts (66/230, 28%) and a marked lack of severe leukoaraiosis identified in only 68/230 (29.6%). A total of 1870 arteries were studied individually. Middle cerebral artery was the symptomatic stroke vessel in half, presenting with complete occlusion in 66%. Evidence of biological disease, symptomatic or asymptomatic was identified in 753 (40.2%) vessels of which 543 (72%) were significantly (\u3e50%) stenosed at presentation. Conclusion: Intracranial atherosclerotic disease is a diffuse process in Pakistani south Asians, with involvement of multiple vessels in addition to the symptomatic vessel. The middle cerebral artery is the most frequent symptomatic vessel presenting with cortical embolic infarcts. There is a relative lack of leukoaraiosis. Concomitant atrophy, silent brain infarcts and recent ischaemia in the symptomatic territory are all frequently associated findings

Regional circulation features associated with precipitation events leeward the Andes

Synoptic and regional-scale conditions associated with precipitation events leeward the Andes in Argentina are studied. Anomaly patterns of mid-tropospheric circulation in conjunction with local precipitation are analysed from Tartagal (about 20\ub0S) to Usuhaia (about 55\ub0S) mainly along the longitude 70\ub0W east of the Andes cordillera in order to examine the anomaly circulation behaviour and seasonality, and also to detect spatial coherence and geographical differences in anomaly patterns having place in precipitating situations. It is worth noting that each one of the regional synoptic map-pattern classifications investigated are appropriate or of exclusive use for the corresponding surface station. There exist separate classification systems for each in situ precipitation, thereby, different responses for each station. Notwithstanding, north of Malargüe (about 40\ub0S) there seem to be regional anomaly patterns in connection with precipitation occurrence substantially different, and perhaps independent from an orthogonal technique point of view, from those occurring to the south. This influence may affect the hydrological environment and the runoff of cordillera rivers. So, this work addresses a climatologic diagnosis study of circulation patterns linking mid-tropospheric dynamics, cyclonicity and anticyclonicity conditions, and wavetrain pattern of anomalies to the local precipitation and in what a way these patterns are evidenced as significantly different with latitude affecting different runoff regimes. These atmospheric patterns are responsible of precipitation production, both liquid and solid, which feeds and controls the cordillera rivers. Consequently, depending on what hemispheric and large-scale factors are acting this would affect or favour a determined anomaly pattern associated which in turn is associated with precipitation at a given locality, and, hence, the runoff variability.Pages: 1969-197