Time use and foraging behaviour in pre-breeding dabbling ducks Anas spp. in sub-arctic Norway

We studied time budgets and foraging methods in pre-breeding Mallard Anas platyrhynchos, (Eurasian) Teal Anas crecca, Wigeon Anas penelope, Pintail Anas acuta, Shoveler Anas clypeata and Gadwall Anas strepera in subarctic Norway in May. Among all six species studied, foraging accounted for the most common use of time, ranging from 19 % in male Pintail to 40–60 % in female Mallard, Teal, Pintail and Gadwall. Comfort behaviours amounted to 20–34 % of the time budget, and interaction and disturbance were marginal. Vigilance time ranged from 8 % in female Mallard to 20 % in male Pintail. Movement amounted to some 20 % of the time in most species and sexes. In Wigeon, sexes did not differ in time use, whereas in Mallard, Pintail and, in particular, Teal, females foraged more and engaged less in vigilance and interactions than did males. In addition, Teal and Mallard males engaged in the riskier foraging methods less than females, but more in those permitting vigilance. Although overlap in feeding methods was large among these species, Mallard and Teal were generalists, feeding at all depths, Wigeon foraged mainly in shallow water and Pintail foraged essentially in deep water. Our results support the income/capital breeder hypothesis with respect to males only; compared to lighter species, heavier species allocated less time to foraging but more to vigilance. We found no support for the hypothesis that long-distance migrants forage more to compensate for energy loss due to migratory flight. Foraging time in females was related to breeding phenology; early nesters spent more time feeding than later nesters.</p

Orthorectification Tests Continued... Formosat-2 Orthorectification Of Formosat-2 Data for use in The Common Agricultural Policy Control with Remote Sensing Programme

FORMOSAT-2 (NSPO, Taiwan) was launched on 21st of May, 2004. FORMOSAT-2 was programmed as Very High Resolution backup sensor in the CwRS campaign for the first time in 2006 [Ref 1]. Acquisition success rate has been high since it was introduced due to its high (daily) revisit capacity, but difficulties were initially encountered to reach the required location accuracy in production of orthorectified imagery. This resulted in a 1st study (2006) where FORMOSAT-2 imagery over Sofia (BG) was assessed; 4 software suites were tested on this image with low off-nadir viewing angle [Ref 2]. Results were promising, demonstrating that it is possible to perform good orthorectification using standard software packages reaching results inside the CwRS requirements for such imagery (location accuracy preliminary set to 3.5m RMSE1D). In this 2nd study (2007) the aim has been to assess the effect of large off-nadir angles on the accuracy of the orthorectification, and to define the optimal number of GCPs to be used when orthorectifying FORMOSAT-2 images on a routine basis. Results of orthocorrection of 4 images of different off-nadir angles (along/across angles), over 2 sites in France and Bulgaria, using 4 different sw suites (PCI, ERDAS Imagine, PRODIGEO, and Keystone SIPOrtho,) and with varying number of GCPs are discussed. The results are consistent with theoretical expectations; x error increases when across angle (roll) increases, the y error increases when along angle (pitch) increases. Basically the accuracy of 5m RMSE1D is reached with all tested softwares, the 3.5m RMSE1D accuracy may be reached if limits are placed on the acquisition angles. Concerning the GCP requirement a total of minimum 10 GCPs should be used: four GCPs spread in the corners of the scenes, the others evenly distributed, and clearly visible.JRC.G.3-Agricultur

Invertebrates are declining in boreal aquatic habitat: the effect of brownification?

Surface water browning affects boreal lakes in the Northern Hemisphere. This process is expected to increase with global warming. Boreal lakes are the most numerous lakes on Earth. These ecosystems are particularly sensitive to disturbances due to their low biodiversity compared to other aquatic environments. The recent darkening of surface water is expected to hinder key ecosystem processes, particularly through lower primary productivity and loss of biodiversity. However, studies based on long-term data collections have rarely been conducted on the ecological consequences of water browning on aquatic food webs, especially concerning its impacts on invertebrate communities.For the first time, our analysis based on two decades of data collection in Finnish lakes highlighted a relation between water browning and a decline in aquatic macroinvertebrate abundances. Aquatic invertebrates are the main food resource for many secondary predators such as fish and waterbirds, hence such effect on their populations may have major consequences for boreal ecosystem functioning.</p

Lead concentrations in blood from incubating common eiders (Somateria mollissima) in the Baltic Sea

Here we investigate if lead may be a contributing factor to the observed population decline in a Baltic colony of incubating eiders (Somateria mollissima). Body mass and blood samples were obtained from 50 incubating female eiders at the Baltic breeding colony on Christiansø during spring 2017 (n = 27) and 2018 (n = 23). All the females were sampled twice during early (day 4) and late (day 24) incubation. The full blood was analysed for lead to investigate if the concentrations exceeded toxic thresholds or changed over the incubation period due to remobilisation from bones and liver tissue. Body mass, hatch date and number of chicks were also analysed with respect to lead concentrations. The body mass (mean ± SD g) increased significantly in the order: day 24 in 2018 (1561 ± 154 g) Peer reviewe

Ecology and extent of freshwater browning - What we know and what should be studied next in the context of global change

Water browning or brownification refers to increasing water color, often related to increasing dissolved organic matter (DOM) and carbon (DOC) content in freshwaters. Browning has been recognized as a significant physicochemical phenomenon altering boreal lakes, but our understanding of its ecological consequences in different freshwater habitats and regions is limited. Here, we review the consequences of browning on different freshwater habitats, food webs and aquatic-terrestrial habitat coupling. We examine global trends of browning and DOM/DOC, and the use of remote sensing as a tool to investigate browning from local to global scales. Studies have focused on lakes and rivers while seldom addressing effects at the catchment scale. Other freshwater habitats such as small and temporary waterbodies have been overlooked, making the study of the entire network of the catchment incomplete. While past research investigated the response of primary producers, aquatic invertebrates and fishes, the effects of browning on macrophytes, invasive species, and food webs have been understudied. Research has focused on freshwater habitats without considering the fluxes between aquatic and terrestrial habitats. We highlight the importance of understanding how the changes in one habitat may cascade to another. Browning is a broader phenomenon than the heretofore concentration on the boreal region. Overall, we propose that future studies improve the ecological understanding of browning through the following research actions: 1) increasing our knowledge of ecological processes of browning in other wetland types than lakes and rivers, 2) assessing the impact of browning on aquatic food webs at multiple scales, 3) examining the effects of browning on aquatic-terrestrial habitat coupling, 4) expanding our knowledge of browning from the local to global scale, and 5) using remote sensing to examine browning and its ecological consequences.</p

Space based tools to monitor the habitats of migratory waterbirds

International audienceNatural fluctuations in the availability of suitable habitat coupled with anthropogenic activities (hunting, agriculture, tourism, urbanism) and anticipated modifications due to climate change confront migratory waterbirds with a formidable challenge. Among them, dabbling ducks, greatly rely on local exogenous resources to fulfil their energy requirements. Habitat suitability along their flyway is of primary importance as any change might induce dramatic effects on individual survival and breeding success. Although, the monitoring of such sensitive flooded areas that are wetlands stopover sites is usually complex, space based techniques, with an exhaustive and systematic covering of the territory and a periodical data acquisition, can explore cost-efficiently the ecological conditions for migratory species in these environments. Hence, multiseason reflectance data from radiometrically and geometrically corrected multispectral SPOT-5 scenes, combined with thorough field campaigns and land cover digitizing using data mining, can provide robust tools for habitat monitoring and help the conservation of wetlands for migrants.</p

Ecologie de la sarcelle d hiver et des autres canards de surface (connexion entre les sites d hivernage, les haltes migratoires et les zones de reproduction)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Population dynamics in the common teal - importance of climate in breeding and wintering areas

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Habitat use in ducks breeding in boreal freshwater wetlands: a review

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