Wyniki wyszukiwania - Biblioteka Nauki

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Eurasian otter (Lutra lutra) density estimate based on radio tracking and other data sources

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Quaglietta L. , Hajkova P. , Mira A. , Boitani L.

Acta Theriologica

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2015

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tom 60

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nr 2

EN

Estimating animal population size is a critical task in both wildlife management and conservation biology. Precise and unbiased estimates are nonetheless mostly difficult to obtain, as estimates based on abundance over unit area are frequently inflated due to the “edge effect” bias. This may lead to the implementation of inappropriate management and conservation decisions. In an attempt to obtain an as accurate and conservative as possible picture of Eurasian otter (Lutra lutra) numbers, we combined radio tracking data from a subset of tracked individuals from an extensive project on otter ecology performed in Southern Portugal with information stemming from other data sources, including trapping, carcasses, direct observation of tagged and untagged individuals, relatedness estimates among genotyped individuals, and a minor contribution from non-invasive genetic sampling. In 158 km of water network, which covers a sampling area of 161 km2 and corresponds to the minimum convex polygon constructed around the locations of five radio-tracked females, 21 animals were estimated to exist. They included the five radio-tracked, reproducing females and six adult males. Density estimates varied from one otter per 3.71–7.80 km of river length (one adult otter per 7.09–14.36 km) to one otter per 7.67–7.93 km2 of range, depending on the method and scale of analysis. Possible biases and implications of methods used for estimating density of otters and other organisms living in linear habitats are highlighted, providing recommendations on the issue.

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Diurnal activity patterns of coypu in an urban habitat

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Meyer J. , Klemann N. , Halle S.

Acta Theriologica

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2005

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tom 50

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nr 2

EN

The ability of species to adapt to changing environmental conditions is a crucial need for surviving in human influenced landscapes. Especially non-indigenous species, which are flexible in their behaviour, may successfully enter and establish in new habitats. We compared the activity patterns of the invasive coypuMyocastor coypus (Molina, 1782) in an urban habitat in Germany with patterns observed in its native distribution range in South America as well as in areas, where it was introduced. In summer 1998 and winter 1999 a radio tracking study was carried out on six adult coypus, supplemented by count data on untagged animals. Whereas main activity in non-urban populations was recorded at night including dusk and dawn, coypus in the urban habitat were active during the day and early evening. We never observed animals between midnight and dawn. This reversal of activity patterns is attributable to deposition of human food in the city area during the daytime.

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Demonstrator miniaturowego nadajnika radiowego przeznaczony do implementacji w systemie lokalizacji obiektów

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Węglarski M. , Cisło D.

Elektronika : konstrukcje, technologie, zastosowania

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2024

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tom Vol. 65, Nr 7

17--21

PL

W badaniach nad lokalizacją obiektów rozrzuconych w środowisku naturalnym wykorzystuje się miniaturowe nadajniki radiowe. W ofercie rozwiązań komercyjnych jest wiele produktów o różnych parametrach funkcjonalnych, niestety te które wykazują najlepszą charakterystykę pracują w pasmach częstotliwości, które w Polsce są przeznaczone do innego rodzaju aplikacji. Dlatego też głównym celem badawczym było zaproponowanie demonstratora pracującego w dozwolonym paśmie i o parametrach lepiej dopasowanych do wymogów aplikacyjnych.

EN

Miniature radio transmitters are utilized in much research on the localization of objects scattered in natural environments. Numerous commercial solutions are available with various functional parameters; unfortunately, those that exhibit the best characteristics operate in frequency bands allocated in Poland for other types of applications. Therefore, the main research goal was to propose a demonstrator that operates within the permitted frequency band and with parameters better suited to specified application requirements.

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Space use of common genets Genetta genetta in a Mediterranean habitat of Northeastern Spain: differences between sexes and seasons

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Camps M. D. , Llimona Llobet F.

Acta Theriologica

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2004

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tom 49

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nr 4

EN

The seasonal home range size and spatial relationships of 16 adult genetsGenetta genetta Linnaeus, 1758 (6 males and 10 females) were estimated in a Mediterranean habitat of northeastern Spain. Genets minimum density was estimated as 0.98/km2. Mean annual home range was 113.1 ha in males and of 72.0 ha in females. Males had larger home ranges than females in all seasons, but differences were only significant in winter. Home range size changed seasonally and showed a similar pattern in both sexes, with lower values in summer (males — 41.2 ha, females — 29.0 ha) and maximum ones in spring (males — 78.8 ha, females — 56.1 ha). Animals displayed spatial fidelity throughout the year. Core areas (MCP50) represented 27% and 19% of total home range size for males and females, respectively. Resting home ranges (based on locations of inactive animals) were 9 times lower than overall home range size. Individuals of the same sex overlapped less than individuals of different sexes, especially with regard to core areas, which showed almost no overlap. The results obtained suggest that (1) different factors are likely to affect the space use of genets, such as body mass, food abundance and reproductive cycle; (2) genets use space in a heterogeneous way, with areas of greater activity than others within their home range; (3) there was intrasexual segregation with regard to space use.

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Vegetation quality and habitat selection by European hares Lepus europaeus in a pastural landscape

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Smith R. K. , Jennings N. V. , Tataruch F. , Hacklander K. , Harris S.

Acta Theriologica

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2005

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tom 50

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nr 3

EN

European haresLepus europaeus Pallas, 1778 have lower population densities and body condition in pastural landscapes than in arable landscapes, but reasons for this are not understood. The aim of this study was to determine whether forage quality is low in pastural landscapes during certain seasons. We carried out chemical analysis of the nutritional quality of 5 habitat types to determine whether hares select high quality habitats, and whether nutritional quality explains seasonal differences in range sizes of hares in pastural landscapes. Hares did not tend to select habitats of high nutritional quality (protein, fat or energy) over those of lower quality. Hares did not increase active range size as the overall energy content of forage at the study site decreased; seasonal differences in active range size were not explained by nutritional quality. Differences may be explained by behavioural changes related to breeding. Pastural habitat is fairly stable in terms of nutritional quality through the year, and results suggest that poor forage quality is unlikely to be responsible for the poor body condition of hares in pastural landscapes. Hares in these landscapes are more likely to be limited by habitat quality in terms of cover than by forage.

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Ecology of Aquatic Warblers Acrocephalus paludicola in a fall stopover area on the Atlantic coast of France

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Musseau R. , Herrmann V. , Benard S. , Kerbiriou C. , Herault T. , Jiguet F.

Acta Ornithologica

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2014

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tom 49

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nr 1

EN

The Aquatic Warbler Acrocephalus paludicola is the only endangered songbird in continental Europe. This trans- Saharan migratory bird significantly transits along the French Atlantic coastline during post-breeding migration and the right bank of the Gironde estuary has been identified as an important stopover site. We studied the spatial occupancy strategies of stationing individuals during August of three successive years (2010-2012). We characterized habitat use by radio-tracking individuals revealing relatively small foraging ranges (6.6 ± 2.6 ha on average) with only 1 ha actually exploited (core area), and a relatively high habitat fragmentation rate. Capture-mark-recapture analyses assessed the average stopover duration of individuals and body-mass variations during their stopover. The estimated average stopover duration was 6.46 ± 0.46 days (95% confidence interval: 4.4-9.6). Lean birds tended to forage significantly more than stout birds: on average, they gain 2.81 ± 0.89% of their initial mass each day whereas stout birds only gain 0.12 ± 0.56%. Analyses of droppings characterized the local diet. We noticed that Aquatic Warbler preferentially used partially-flooded or flooded habitats with heterogeneous and rather low vegetation, such as bulrush beds or bulrush beds mixed with reed beds. Orthoptera, Araneae and Hymenoptera represented the largest contributions to the consumed biomass (64.7%, 13.4% and 8.9% respectively). The importance of the fuel deposition rate of lean birds reflects the importance of the estuary as a stopover site for the species. It means that the available resources allow birds to replenish and continue their migration route. However, the sustainability of the site's functionality is questioned because of the evolution of habitats (erosion, rise in water levels and changes in food web).

PL

Wodniczka jest jedynym zagrożonym gatunkiem z grupy śpiewających ptaków wróblowych. Podczas wędrówki jesiennej gatunek ten leci wzdłuż atlantyckiego wybrzeża Francji, a estuarium Żyronda (powstałe z połączenia rzek Garonny i Dordogne) jest jego ważnym miejscem przystankowym. W latach 2010-2012 badano w tym miejscu: wielkość areału, wybiórczość siedliskową, czas pozostawania na miejscu przystankowym, tempo uzupełniania zapasów oraz dietę wodniczki. Ptaki chwytane były w sieci na prawym brzegu Żyrondy przez cały sierpień. W latach 2010-2011 20 osobników wyposażono w nadajniki telemetryczne. Średni czas namierzania ptaków z nadajnikami wynosił 3,35 dnia. Łącznie zebrano dane o 926 lokalizacjach na obszarze o powierzchni 121,21 ha (Fig. 1). Wykazano, że wodniczki wykorzystywały do żerowania niewielkie areały. Średnio miały one powierzchnię 6,6 ha, z jednohektarowym terenem głównego żerowiska. Areały były dość mocno pofragmentowane. Część ptaków przenosiła się z miejsc schwytania na dalsze tereny estuarium, najdalej 1 940 m od miejsca wypuszczenia (Fig. 1). Ptaki najczęściej stwierdzane były na terenach zalanych lub w strefie pływów porośniętych zróżnicowaną i raczej niską roślinnością, taką jak sitowie lub sitowie z trzcinowiskiem. Na podstawie wielokrotnych schwytań tych samych osobników wyliczono parametry przeżywalności i prawdopodobieństwa schwytania (Tab. 1 2). Średnia długość okresu pozostawania przez ptaki na miejscu przystankowym wynosiła 6,46 dnia. Analizowano także tempo uzupełniania zapasów tłuszczowych (RDF — relative fuel deposition) oraz wpływ na ten parametr minimalnej długości przebywania na miejscu przystankowym (MLS — minimum length stopover) oraz indeksu masy ciała w czasie pierwszego schwytania (IBMI — initial body mass index). Stwierdzono, że ptaki przylatujące z niewielkimi zapasami uzupełniały je w znacznie szybszym tempie niż te posiadające ich więcej (Fig. 2). W diecie wodniczek na badanym miejscu przystankowym największą rolę odgrywały prostoskrzydłe, pajęczaki i błonkoskrzydłe (Tab. 3).

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Interannual fidelity to roosting habitat and flight paths by female western barbastelle bats

67%

Hillen J. , Kiefer A. , Veith M.

Acta Chiropterologica

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2010

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tom 12

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nr 1

EN

The roost area selection of reproductive female western barbastelles was examined throughout four study seasons (2004–2007) via radio-tracking and automated acoustic monitoring. We specifically analysed the spatial structure of the roosting habitat and roost fidelity including a flight path connecting the roosts. We radio-tracked 13 colony members to 46 natural roosts, mainly dead oaks with large pieces of loose bark. Simultaneous tracking of four pairs of females revealed the existence of subgroups and fission-fusion-behaviour in Barbastella barbastellus. The colony displayed fidelity to the roost area rather than to single roost trees, although some trees were reused in two or three study seasons. Bimodal activity patterns obtained from acoustic monitoring indicated that the flight path connecting two core roosting areas functioned as a commuting corridor.