Nest-site selection and characteristics in a mixed-species colony of Avocets Recurvirostra avosetta and Black-winged Stilts Himantopus himantopus

Capsule Causes of breeding failure determined optimal nest location, Black-winged Stilts being better adapted than Avocets to nest close to water.

Aims To compare nest size and location between the two species and to test whether there were inter-species differences that might suggest specific nesting adaptations, and to investigate possible correlates between hatching success and nest location.

Methods Nest-site selection, characteristics and hatching success were studied during 1989 in a large mixed-species colony located in southern Spain.

Results Black-winged Stilt nests differed in composition and size depending on distance to water (nests touching the water were larger and included mud), but Avocet nests did not. Avocets nests were more aggregated and central within the colony than those of Black-winged Stilts. Causes of breeding failure were flooding and rat predation. Successful or unsuccessful Black-winged Stilt nests did not differ significantly in characteristics or location. Successful Avocet nests were further from water than flooded nests and further from dry land than depredated ones. Distance to the centre of the colony did not affect hatching success.

Conclusion Black-winged Stilts were better adapted than Avocets to nest near water, due to their greater plasticity in nest-building behaviour. Causes of breeding failure determined optimal nest location.     

Environmental Instability as a Motor for Dispersal: A Case Study from a Growing Population of Glossy Ibis

Dispersal is a life-history trait directly affecting population dynamics and species range shifts and thus playing a prominent role in the response to climate change. Nonetheless, the relationship between extreme climatic events and dispersal has received little attention in birds. Here we focused on climatic, demographic and individual factors affecting the dispersal propensity of a major glossy ibis population. We performed a capture-resighting analysis on individuals born and observed at Doñana (South-West Spain) over fourteen years. We applied a multiple analytical approach to show that single-site capture-resighting estimates were a reliable index of dispersal propensity from the area. We focused on the emigration of Doñana-born individuals sporadically (transients) and regularly (residents) frequenting their natal area. Droughts during two out of 14 study years caused higher apparent dispersal rates, explaining most of the annual variation in these rates. The age structure of Doñana-born individuals resighted simultaneously locally and in Morocco in one week over the 2010 autumn confirmed that the 2005 drought boosted permanent emigration. As numbers increased steadily during non-drought years since the formation of the colony in 1996 to several thousand pairs, philopatry increased gradually, while transients probability appeared to be related to average breeding success. Age, sex, density, quality of foraging habitat and breeding success in the previous season were not found to directly affect apparent dispersal. Nonetheless, autumn sex ratio gradually switched from male (≈0.68) to female-skewed (≈0.44) by the end of the study period, suggesting that males and females respond differently to high densities reached in recent years. This study demonstrates the importance of extreme climatic events as a powerful motor for spread of species in expansion. Also, it suggests different factors drive emigration of individuals according to their amount of experience in the area (e.g. transients vs residents).     

Contribution of Do?ana Wetlands to Carbon Sequestration

Inland and transitional aquatic systems play an important role in global carbon (C) cycling. Yet, the C dynamics of wetlands and floodplains are poorly defined and field data is scarce. Air-water fluxes in the wetlands of Doñana Natural Area (SW Spain) were examined by measuring alkalinity, pH and other physiochemical parameters in a range of water bodies during 2010–2011. Areal fluxes were calculated and, using remote sensing, an estimate of the contribution of aquatic habitats to gaseous transport was derived. Semi-permanent ponds adjacent to the large Guadalquivir estuary acted as mild sinks, whilst temporal wetlands were strong sources of (−0.8 and 36.3 ). Fluxes in semi-permanent streams and ponds changed seasonally; acting as sources in spring-winter and mild sinks in autumn (16.7 and −1.2 ). Overall, Doñana''s water bodies were a net annual source of (5.2 ). Up–scaling clarified the overwhelming contribution of seasonal flooding and allochthonous organic matter inputs in determining regional air-water gaseous transport (13.1 ). Nevertheless, this estimate is about 6 times < local marsh net primary production, suggesting the system acts as an annual net sink. Initial indications suggest longer hydroperiods may favour autochthonous C capture by phytoplankton. Direct anthropogenic impacts have reduced the hydroperiod in Doñana and this maybe exacerbated by climate change (less rainfall and more evaporation), suggesting potential for the modification of C sequestration.     

Unmanned Aircraft Systems for Studying Spatial Abundance of Ungulates: Relevance to Spatial Epidemiology

Complex ecological and epidemiological systems require multidisciplinary and innovative research. Low cost unmanned aircraft systems (UAS) can provide information on the spatial pattern of hosts’ distribution and abundance, which is crucial as regards modelling the determinants of disease transmission and persistence on a fine spatial scale. In this context we have studied the spatial epidemiology of tuberculosis (TB) in the ungulate community of Doñana National Park (South-western Spain) by modelling species host (red deer, fallow deer and cattle) abundance at fine spatial scale. The use of UAS high-resolution images has allowed us to collect data to model the environmental determinants of host abundance, and in a further step to evaluate their relationships with the spatial risk of TB throughout the ungulate community. We discuss the ecological, epidemiological and logistic conditions under which UAS may contribute to study the wildlife/livestock sanitary interface, where the spatial aggregation of hosts becomes crucial. These findings are relevant for planning and implementing research, fundamentally when managing disease in multi-host systems, and focusing on risky areas. Therefore, managers should prioritize the implementation of control strategies to reduce disease of conservation, economic and social relevance.     

Organophosphate Pesticide Poisoning

A total of 118 workers from a 120-person grape picking crew became ill in early September 1976. Of these (108 men and 10 women), 85 received medical attention and three of the 85 were admitted to hospital. The symptoms were typical for organophosphate poisoning. Average plasma and red cell cholinesterase values for the affected workers were depressed more than 60 percent. Most were treated with atropine and some were also treated with 2-PAM (pralidoxime). The exposure to residues of the organophosphate pesticides dialifor (Torak^®) and phosalone (Zolone^®) occurred in one grower''s vineyards near Madera, California.It appeared that workers had been allowed into recently-treated areas before the expiration of the required 30-day safety interval for dialifor, and that excessive skin exposure to residues of this pesticide had resulted. The clinical management of these cases and the occupational surveillance of the workplace became quite complex.The grower sustained significant losses of grapes during the period in which some of his vineyards were under quarantine and he had to pay substantial medical expenses as well as a fine for violating state regulations concerning the proper use of pesticides.Organophosphate pesticides decay more slowly under hot, dry weather conditions than they do when rainfall is frequent. California has imposed a number of specific safety intervals to be observed after the application of these pesticides to certain crops. If, in violation of these regulations, workers are permitted to enter fields too soon, poisoning can occur.     

Possible mechanism of pesticide toxicity-related oxidative stress leading to airway narrowing

The study was conducted to assess the magnitude of oxidative stress and lung function abnormalities in 34 male pesticide sprayers on exposure to pesticides in mango plantations. Biochemical studies on blood antioxidant enzymes revealed an unchanged glutathione level and increased level of malondialdehyde (P < 0.001), which indicates that pesticide sprayers may have suffered from oxidative stress. Decreased acetyl-cholinesterase levels (P < 0.001) in sprayers compared to the controls suggest inhibition of cholinesterase activity. The present study shows that pesticide toxicity might lead to oxidative stress and airway narrowing resulting in decreased peak expiratory flow rate.     

Evidence of high-energy events in the geological record: Mid-holocene evolution of the southwestern Doñana National Park (SW Spain)

Four phases are distinguished in the Mid-Holocene evolution of the southwestern Doñana National Park (SW Spain), based on the multidisciplinary study of sediments in drill cores. In the oldest phase (> 5500-5400 cal. years BP), a coastal, brackish lagoon occupied the central part of the study area, partly enclosed by the Doñana spit and limited by fluvial levees. An evolution from subtidal to intertidal conditions characterized the areas located close to the inner side of the Doñana spit during the same phase. The following phase (∼5400-5200 cal. years BP) is characterized by a high-energy event (tsunami?), which caused the breakthrough of the Doñana spit and the creation of new littoral strands in the inner areas. In the first period of the third phase (∼5200-4200 cal. years BP), estuarine infilling was probably the dominant process, with the accumulation of phyllosilicate-rich clays in the lagoon bed. This was followed by a renewed phase of instability (∼4200-4100 cal. years BP) indicated by the presence of fine storm-lain deposits and thicker, probably tsunami-induced shelly deposits. The last phase (∼4100-3700 cal. years BP) comprises: a) an infilling period, with a diminution of the marine influence; and b) two new high-energy events, which caused the erosion of the Doñana spit and the creation of new cheniers.In the last 7000 years, the comparison of these results with a revision of both geological and historical records has revealed the occurrence of twenty tsunamis (at least) during this period in Portugal and southern Spain. Evidences of these high-energy events are washover fans, bioclastic coarse-sized layers within salt marsh deposits or the presence of giant boulders and pebbles. The determination of the recurrence period is very difficult owing to the very scarce data, although our data and other authors do not discard a possible periodicity of 2000 years for a cycle of two events separated by 300-400 years.     

Compatibility of early natural enemy introductions in commercial pepper and tomato greenhouses with repeated pesticide applications

Successful integrated pest management in protected crops implies an evaluation of the compatibility of pesticides and natural enemies (NE), as control strategies that only rely on one tactic can fail when pest populations exceed NE activity or pests become resistant to pesticides. Nowadays in Almería (Spain), growers release NE prior to transplanting or early in the crop cycle to favor their settlement before pest arrival because this improves biocontrol efficacy, although it extends pesticide exposure periods. The purpose of this research was to evaluate the compatibility of two applications of pesticides with key NE in 2‐year trials inside tomato and sweet pepper commercial greenhouses: Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae), Orius laevigatus (Say) (Hemiptera: Anthocoridae) and Amblyseius swirskii (Athias‐Henriot) (Acari: Phytoseiidae). In tomato, flubendiamide and chlorantraniliprole (IOBC category 1) were compatible with N. tenuis, but chlorpyrifos‐methyl and spinosad (IOBC categories 2–3), which effectively reduced Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) density, compromised its predatory activity. In sweet pepper, chlorantraniliprole (IOBC category 1) was the only pesticide compatible with O. laevigatus while chlorantraniliprole, emamectin benzoate, spirotetramat and pymetrozine were harmless (IOBC category 1) to Amblyseius swirskii, and sulfoxaflor slightly harmful (IOBC category 2) to this phytoseiid predator.     

Comparative day and night feeding strategies of shorebird species in a tropical environment

A study was carried out in northeastern Venezuela to determine whether or not shorebirds feed at night in tropical environments. Results show that some Neotropical residents and Nearctic winter migrants feed during darkness. During daylight, Black-winged Stilts Himantopus himantopus, mexicanus group, were predominantly visual foragers (75% attempts were pecking), performing a tactile type of feeding technique (immersion of the whole head and portion of the neck while searching for food through soft mud) on other occasions. During night-time, they were almost equally visual (pecking) and tactile (multiple scythelike sweeps) foragers. Greater and Lesser Yellowlegs Tringa melanoleuca and T. flavipes foraged visually during daylight and tactilely (sidesweeping) at night. Short-billed Dowitchers Limnodromus griseus were tactile feeders (probers) both by day and by night while Semipalmated Plovers Charadrius semipalmatus during daylight and at night and Wilson's Plovers C. tvilsonia by night were sight feeders (peckers). Prey abundance was higher at night than during daylight. Black-winged Stilts and yellowlegs seemed to feed at night on food items at least partly different from those they fed upon during daylight.     

Combined effect of short-term dehydration and sublethal acute oral dicrotophos exposure confounds the diagnosis of anticholinesterase exposure in common quail (Coturnix coturnix) using plasma cholinesterase activity

Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on cholinesterase activity in brain and plasma and the interaction between dehydration and exposure to the organophosphorus pesticide dicrotophos in these same tissues. Our objective was to determine if dehydration could confound the diagnosis of anticholinesterase exposure using inhibition of cholinesterase activity in quail tissues. The effect of dehydration was quantified using measures of plasma osmolality and hematocrit. Dicrotophos exposure caused significant inhibition of cholinesterase activity in brain, while the effects of dehydration and interaction were not significant. Dehydration caused significant duration-dependent increases in plasma osmolality and hematocrit. Dehydration also caused a significant increase in plasma cholinesterase activity. Variation in the change in plasma cholinesterase activity in response to dehydration was significantly and positively correlated with dehydration-induced variation in both the change in plasma osmolality and the change in hematocrit. These correlations suggest that plasma cholinesterase activity in quail is not limited to plasma but occupies some larger pool of the extracellular fluid volume, and we suggest lymph is part of that pool. The effects of dehydration on plasma cholinesterase activity masked the inhibitory effects of dicrotophos. Here, the combination of dehydration and dicrotophos exposure produced plasma cholinesterase activity that was not significantly different from reference and pre-exposure values, confounding the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail. A method to adjust plasma cholinesterase activities for the confounding effects of dehydration and enable the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail was developed. Clinicians and practitioners responsible for the diagnosis of anticholinesterase exposure in birds are cautioned that dehydration, commonly observed in sick wildlife, may mask the effect of anticholinesterases on plasma cholinesterase activity.     

Possible mechanism of pesticide toxicity-related oxidative stress leading to airway narrowing

Abstract

The study was conducted to assess the magnitude of oxidative stress and lung function abnormalities in 34 male pesticide sprayers on exposure to pesticides in mango plantations. Biochemical studies on blood antioxidant enzymes revealed an unchanged glutathione level and increased level of malondialdehyde (P < 0.001), which indicates that pesticide sprayers may have suffered from oxidative stress. Decreased acetyl-cholinesterase levels (P < 0.001) in sprayers compared to the controls suggest inhibition of cholinesterase activity. The present study shows that pesticide toxicity might lead to oxidative stress and airway narrowing resulting in decreased peak expiratory flow rate.     

稻田水质模型研究和应用进展

水稻生产环境特殊、生产过程中病虫草害严重,导致农药使用品种多、频次高.部分农药会淋失到周围水体中,对水体的潜在污染风险较高.随着农药监测和田间试验成本的不断提高,数学模型已成为农药登记过程中不可或缺的一部分.稻田水质模型(RICEWQ模型)作为欧洲稻田农药暴露评估最可靠和应用最广泛的模型,主要用于预测淹水稻田土壤和积水中的农药浓度,在我国也得到了初步应用.本文简要介绍了RICEWQ模型的系统结构、农药归趋的主要过程、模型的输入输出,综述了国内外相关的研究进展,以期推进RICEWQ模型在我国的应用,并为相关研究提供参考.     

Using dried blood spots stored on filter paper to measure cholinesterase activity in wild avian species.

Birds of prey that are poisoned by cholinesterase inhibitors (e.g. organophosphate and carbamate insecticides) are often cared for at animal shelters, rehabilitation centres and wildlife diagnostic facilities. Plasma cholinesterase (ChE) activity is a recognized method of assessing exposure to these insecticides, but standard blood-handling protocols are difficult to follow in non-laboratory settings. The primary objective of this study was to expand upon a method for storing human blood on filter paper without the need for complicated equipment or refrigeration, and to test its utility for measurement of ChE activity in avian blood. ChE activity from whole blood, plasma, and dried blood spots was analysed from 169 wild birds and comparisons made among sample types. ChE activity measured in whole blood haemolysates and dried blood spots were significantly correlated (r = 0.74, p < 0.001), as was ChE activity measured in plasma and dried blood spots (r = 0.68, p < 0.001). This study demonstrated that monitoring pesticide exposure in birds could be conducted using elementary blood sampling, preserving and shipping techniques.     

Lecane donyanaensis n. sp. (Rotifera: Monogononta,Lecanidae) from the Doñana National Park (Spain)

A hitherto unknown rotifer species was found in ponds of Doñana National Park (Spain) during winter 1990, 1991 and 1992. It belongs to the family Lecanidae (Monogononta), is related to Lecane ungulata and superficially resembles Lecane leontina.Two specimens of this species hatched after two days incubation of pond sediments in the laboratory.     

Transgenic Bacillus thuringiensis (Bt) Rice Is Safer to Aquatic Ecosystems than Its Non-Transgenic Counterpart

Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.     

Knowledge,attitudes, and practices (KAP) related to blood cholinesterase level among tobacco farmers in Northern Thailand

Abstract

Tobacco is one of the crops using a lot of pesticides, especially organophosphate and carbamate pesticides. A cross-sectional study was conducted to investigate knowledge, attitudes, and Practices (KAP) related to blood cholinesterase levels related to pesticide use among tobacco farmers. A questionnaire and a reactive-paper finger blood test were completed by 44 tobacco farmers. The results showed that most of the participants were females (75.0%) between 51 and 60 years old (54.5%). Almost 95.5% of respondents acknowledged that they should wear a mask while spraying and most of them read pesticide labels before use (93.2%). Most of the tobacco farmers had moderate level of knowledge and attitudes, 63.6% and 70.5%, respectively and good practice (84.1%). The prevalence of risky levels of blood cholinesterase among tobacco farmers in the study area was high. The study found a strongly significant association between level of knowledge and blood cholinesterase level (P < 0.001). Policy implementation and risk communication will be introduced to the community in order to develop a safety program. Government authorities should be provided with the appropriate recommendations regarding pesticide exposure of tobacco farmers in this area.     

Using dried blood spots stored on filter paper to measure cholinesterase activity in wild avian species

Birds of prey that are poisoned by cholinesterase inhibitors (e.g. organophosphate and carbamate insecticides) are often cared for at animal shelters, rehabilitation centres and wildlife diagnostic facilities. Plasma cholinesterase (ChE) activity is a recognized method of assessing exposure to these insecticides, but standard blood-handling protocols are difficult to follow in non-laboratory settings. The primary objective of this study was to expand upon a method for storing human blood on filter paper without the need for complicated equipment or refrigeration, and to test its utility for measurement of ChE activity in avian blood. ChE activity from whole blood, plasma, and dried blood spots was analysed from 169 wild birds and comparisons made among sample types. ChE activity measured in whole blood haemolysates and dried blood spots were significantly correlated (r=0.74, p<0.001), as was ChE activity measured in plasma and dried blood spots (r=0.68, p<0.001). This study demonstrated that monitoring pesticide exposure in birds could be conducted using elementary blood sampling, preserving and shipping techniques.     

Effects of azinphos methyl and carbaryl on Rhinella arenarum larvae esterases and antioxidant enzymes

Organophosphate (OP) and carbamate pesticides are anticholinesterasic agents also able to alter antioxidant defenses in different organisms. Amphibian larvae are naturally exposed to these pesticides in their aquatic environments located within agricultural areas. We studied the effect of the carbamate carbaryl (CB) and the OP azinphos methyl (AM), compounds extensively used in Northern Patagonian agricultural areas, on reduced glutathione (GSH) levels and the activities of esterases and antioxidant enzymes of the toad Rhinella arenarum larvae. Larvae were exposed 48 h to AM 3 and 6 mg/L or CB 10 and 20 mg/L. Cholinesterase and carboxylesterases were strongly inhibited by CB and AM. In insecticide-exposed larvae, carboxylesterases may serve as alternative targets protecting cholinesterase from inhibition. GSH-S-transferase (GST) activity was significantly increased by CB and AM. Superoxide dismutase activity increased in tadpoles exposed to 6 mg/L AM. Conversely, catalase (CAT) was significantly inhibited by both pesticides. GSH levels, GSH reductase and GSH peroxidase activities were not significantly affected by pesticide exposure. GST increase constitutes an important adaptive response to CB and AM exposure, as this enzyme has been related to pesticide tolerance in amphibian larvae. Besides, the ability to sustain GSH levels in spite of CAT inhibition indicates quite a good antioxidant response. In R. arenarum larvae, CAT and GST activities together with esterases could be used as biomarkers of CB and AM exposure.     

Adapting to a Changing World: Unraveling the Role of Man-Made Habitats as Alternative Feeding Areas for Slender-Billed Gull (Chroicocephalus genei)

Current rates of wildlife habitat loss have placed increasing demands on managers to develop, validate and implement tools aimed at improving our ability to evaluate such impacts on wildlife. Here, we present a case study conducted at the Natural Area of Doñana (SW Spain) where remote sensing and stable isotope (δ¹³C, δ¹⁵N) analyses of individuals were combined to unravel (1) the effect of variations in availability of natural food resources (i.e. from natural marshes) on reproductive performance of a Slender-billed Gull (Chroicocephalus genei) population, and (2) the role of two adjacent, artificial systems (a fish farm and saltmines) as alternate anthropogenic feeding areas. Based on long-term (1983–2004) remote-sensing, we inferred the average extent of flooded area at the marshland (a proxy to natural resource availability) annually. Estimated flooded areas (ranging from extreme drought [ca. 151 ha, 1995] to high moisture [15,049 ha, 2004]) were positively related to reproductive success of gulls (estimated for the 1993–2004 period, and ranging from ca. 0 to 1.7 fledglings per breeding pairs), suggesting that habitat availability played a role in determining their reproductive performance. Based on blood δ¹³C and δ¹⁵N values of fledglings, 2001–2004, and a Bayesian isotopic mixing model, we conclude that saltmines acted as the main alternative foraging habitat for gulls, with relative contributions increasing as the extent of marshland decreased. Although adjacent, anthropogenic systems have been established as the preferred breeding sites for this gull population, dietary switches towards exploitation of alternative (anthropogenic) food resources negatively affected the reproductive output of this species, thus challenging the perception that these man-made systems are necessarily a reliable buffer against loss of natural feeding habitats. The methodology and results derived from this study could be extended to a large suite of threatened natural communities worldwide, thus providing a useful framework for management and conservation.     

Identifying new buffer areas for conserving waterbirds in the Mediterranean basin: the importance of the rice fields in Extremadura,Spain

The impact of wetland loss on migratory waterbirds can be mitigated by the presence of anthropogenic habitats such as rice fields. In the Mediterranean basin, wetlands have been drained and altered to such a degree that their very existence is threatened. It is, therefore, essential to identify key buffer areas in the basin to develop conservation strategies for migratory waterbirds. In Extremadura, continental SW Spain, 30,000 ha of new rice fields have created since the 1960s. The present study describes for the first time the waterbird community associated with these inland rice fields, and addresses the question of the potential value of this area in buffering the loss of natural wetlands for populations of waterbirds using the East Atlantic Flyway (EAF). The waterbird community studied consisted of 45 species, with population levels reaching values of international importance (>1% of the biogeographical population using EAF) for the Common Crane Grus grus (19%), Black-tailed Godwit Limosa limosa (1.2%), Black-winged Stilt Himantopus himantopus (1.2%), and Cattle Egret Bubulcus ibis (1%). The presence of these rice fields may be modifying the wintering and/or feeding sites of some waterbird species such as the Common Crane and Black-tailed Godwit. Unfortunately, there is no legal protection for this area. We propose the designation of these rice fields as a Special Protection Area for birds.