172 research outputs found
Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus
No full textBiffi, Marjorie, Laffaille, Pascal, Buisson, Laëtitia (2020): Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus. Mammalia (Warsaw, Poland) 84 (1): 50-62, DOI: 10.1515/mammalia-2018-0035, URL: http://dx.doi.org/10.1515/mammalia-2018-003
Fontaine-Laffaille modules and strongly divisible modules
No full textIn this note, we study the relation between Fontaine-Laffaille modules and
strongly divisible modules, without assuming the main theorem of
Fontaine-Laffaille (but we need to assume the main results concerning strongly
divisible modules). This in particular gives a new proof for the main theorem
of Fontaine-Laffaille (for ).Comment: Final version. Updated numbering system to match with published
versio
Figure 1 in Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus
No full textFigure 1: Location of the study area and sampling sites (black dots) in the French Pyrenees.Published as part of Biffi, Marjorie, Laffaille, Pascal & Buisson, Laëtitia, 2020, Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus, pp. 50-62 in Mammalia (Warsaw, Poland) 84 (1) on page 52, DOI: 10.1515/mammalia-2018-0035, http://zenodo.org/record/783773
Feeding competition between two goby species, Pomatoschistus lozanoi (de Buen) and P. minutus (Pallas), in a macrotidal satmarsh.
No full textTwo transient goby species (Pomatoschistus minutus and P. lozanoi) occurred in saltmarshes of the macrotidal Mont Saint Michel bay. They colonised the tidal creeks during each spring tide all along the study conducted in 1997. P. minutus swallowed a least 4% of its body weight. Its diet was dominated by the most abundant resident amphipod of the saltmarshes, Orchestia gammarellus. P. lozanoi ingested less food during their stay in the creek (2.4% of its body weight). O. gammarallus also occurred in its diet, but mysids were the main food items both during flood and ebb. In addition to this trophic segregation, a temporal segregation was observed. In fact, P. minutus stayed longer than P. lozanoi in the saltmarsh ; it colonised creeks first and returned to coastal waters the last. These two predatory and sympatric species had a different trophic behaviour that limited interspecific competition both from the trophic and temporal point of view
Figure 2 in Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus
No full textFigure 2: Explanatory power (% of deviance explained) of GLMs relating the number of Pyrenean desman faeces to a single category of abiotic or biotic variables ("models by category"). See Table 1 for details about the variables belonging to each category.Published as part of Biffi, Marjorie, Laffaille, Pascal & Buisson, Laëtitia, 2020, Local habitat preferences of a semi-aquatic mammal, the Pyrenean desman Galemys pyrenaicus, pp. 50-62 in Mammalia (Warsaw, Poland) 84 (1) on page 55, DOI: 10.1515/mammalia-2018-0035, http://zenodo.org/record/783773
Assessing the freshwater distribution of yellow eel
No full textIn the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (≤ 300 mm) along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data) using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species
Effect of water warming on the structure of biofilm-dwelling communities
No full textMajdi N, Uthoff J, Traunspurger W, Laffaille P, Maire A. Effect of water warming on the structure of biofilm-dwelling communities. Ecological Indicators. 2020;117: 106622
The yellow European eel (Anguilla anguilla L.) may adopt a sedentary lifestyle in inland freshwaters
No full textWe analysed the movements of the growing yellow phase using a long-term mark–recapture programme on European eels in a small catchment (the Frémur, France). The results showed that of the yellow eels (>200 mm) recaptured, more than 90% were recaptured at the original marking site over a long period before the silvering metamorphosis and downstream migration. We conclude that yellow European eels >200 mm may adopt a sedentary lifestyle in freshwater area, especially in small catchment
Strategy of recreational anglers and estimated eel (Anguilla anguilla) catches in a large European catchment basin, the Loire (France)
No full textThe European Council Regulation (18 September 2007) for the recovery of eel stocks required European states to report on eel stocks and anthropic mortalities. The data sources for France reveal gaps in our knowledge about angling in the public domain, and catches from privately-owned rivers. We tested a simple method, using a survey, for estimating the strategy employed and the catches landed by the 350 000 anglers fishing in the Loire catchment area. The first findings show that the answers of the fishermen varied between 1 and 2% in the departments with the most eels, and between 0.1 and 0.2% in the departments located further upstream. The interest in eel fishing, the average weight of the eels caught by the fishermen, and the total catch all decreased from downstream to upstream. Finally, we estimated the annual average weight of eel caught by anglers, which ranged from 0.8 to 5.3 kg per year depending on the department and the local interest in eel fishing. This preliminary study shows that it is possible to estimate the different fishing strategies used and the quantities caught by means of a survey
Migration pattern of silver eel (Anguilla anguilla, L.) in an obstructed river system.
No full textThe downstream migration of European silver eels in the River Frémur was examined to determine the potential effects of the numerous migration barriers that exist on waterways in western France. The Frémur has a 14 m high dam which creates a 3 · 106 m3 water supply reservoir, 6 km from tidal limit. Based on 8-year records (1996–2004) of migrant silver eels captured in a Wolf trap located about 1 km below the dam, the influence of this dam on the migration was examined. These records indicate that 91% of silver eels were captured when the dam was overtopped (i.e. when the water reservoir was full). The timings of the overflow periods varied greatly between years mainly because they are function of the duration of the filling period which in turn is dependent on the level of summer water abstraction and annual hydrological conditions. Consequently, migration periods occurred at variable dates (between November and April) which is late in comparison with nonobstructed European river systems (generally between August and December). During overflow periods the migration of silver eels increased markedly during rain events (increasing river flow). This indicates that flow flushes, are essential so that settled silver eels can orientate themselves and pass over the dam. The hypothesis of a ‘dam effect’ that could stop temporarily or permanently some of silver eels in the reservoir is discussed. Finally, the influence of the migration delays on the condition of silver eels is considered
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