Wyniki wyszukiwania - Biblioteka Nauki

1

Population ecology and population genetics. Expectations and limitations

100%

Falinska K.

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tom 72

2

Factors determining the distribution of coexisting dormouse species [Gliridae, Rodentia]

67%

Bako B. , Hecker K.

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nr 3

EN

This study investigated coexistence of three dormouse species living in the same habitat, Naszály-hill, in the north-eastern part of the Danube-bend (47°49’N, 19°08’E). The vegetation of the area is very diverse, comprising a mosaic of orchards with natural forests and forest plantations. Data were collected from 1999 to 2005 with wooden nest boxes and from 2002 to 2005 also plastic nest tubes were used. Study area was approximately 6 ha. All three species (hazel dormouse Muscardinus avellanarius L., forest dormouse Dryomys nitedula Pall. and fat dormouse Glis glis L.) have different ecological requirements. However, they occurred simultaneously in some microhabitats and in some places one species clearly predominated. We also observed how the ongoing succession process in the former orchards affected the distribution of dormice. There were seasonal differences in timing of emergence from hibernation, greatly affecting spatial distribution of the different species. Hazel dormice were first to appear in nest boxes and/or tubes, in March, then forest dormice in April and fat dormice in June. As numbers of fat dormice increased the smaller species withdrew from using the nest boxes. Fat dormice reached peak numbers in summer and they entered hibernation by October.

3

Population ecology of free-ranging urban dogs in West Bengal, India

67%

Pal S. K.

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nr 1

EN

A population of urban free-ranging dogs Canis familiaris Linnaeus, 1758 was studied in Katwa, West Bengal, India. The analysis of changes in the density of the dog population over a period of 4 years revealed a considerable stability of this population. Mean (±SD) seasonal population density was 185 ± 19 dogs/km , ranging from 156 to 214 dogs/km . A sex ratio of 1.37:1 in favour of male was recorded in this study. High mortality (67%) occurred under the age of 4 months, and 82% mortality occurred within the age of 1 year. Among the adults, 24% mortality under the age of 2.6 year was recorded. Only a single breeding cycle and synchronization of breeding was observed. Immigration was observed as a crucial factor affecting the stability of this population.

4

The use of space by translocated edible dormice, Glis glis [L.], at the site of their original capture and the site of their release: radio-tracking method applied in a reintroduction experiment

67%

Jurczyszyn M.

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nr 3

EN

A study was made of the use of space by two groups (each of 6 animals) of adult edible dormice (G. glis) at the sites of their origin and where they were released. The reintroduction took place in Szczeciński Landscape Park (north-western Poland; 53°17’N, 14°46’E). The source sites for the animals were in the Sie rakowski Landscape Park (western Poland; 52°38’N, 16°07’E) and a nature reserve “Buczyna Szprotawska” in south-western Poland (51°30’N, 15°40’E). All three sites had dense and extensive mixed forests. At release and source sites, dormice were radio-tracked during 10 successive nights between 20.00 and 05.00 at 1-hour intervals. At the source sites, the mean distance travelled per night and mean home range (95% Minimum Convex Polygon) (MCP) tended to be larger in males than in females but not significantly. At the release sites, the mean distance travelled per night and mean home range were significantly larger in females than in males. The mean distance travelled per night by males and their mean home range size did not differ significantly between source and release sites (although distances were larger at the source sites (source: 458 m; release: 265 m) and home ranges larger at the release sites (source: 1.3 ha; release: 1.8 ha). In contrast, the mean female distance travelled per night (source: 214 m; release: 404 m) and mean home range (source: 0.3 ha; release: 3.5 ha) were significantly larger at the release site than at the source sites.

5

Food preferences of Glis glis [L.], Dryomys nitedula [Pallas] and Graphiurus murinus [Smuts] kept in captivity

67%

Nowakowski W. K. , Remisiewicz M. , Kosowska J.

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nr 3

EN

We investigated food preferences of three species of dormice, testing consumption by captive animals. One type of food was provided to an animal and its “suitability” scored for each species, according to whether it was or was not consumed. If it was eaten, the time when it was consumed was recorded (after 24, 48 or 72 hours). In total, 17 types of animal food and 46 of plant food were tested. Animal foods offered included different arthropods, eggs, snails and chicken meat. Plant food consisted of fruits, seeds, nuts and green parts. Glis glis consumed – 24% of animal material offered and 100% of plant food types, Dryomys nitedula consumed – 77% of animal and 54% of plant food types. Graphiurus murinus consumed – 94% of animal and 63% of plant food types. G. glis showed a significantly higher preference for plant foods rather than animal material, and preferred plant food much more than the other two species. Both D. nitedula and G. murinus preferred animal more than plant food and did not differ in preferences and diversity of both kinds of food they consumed. Thus, G. glis can be considered as principally a herbivore, while D. nitedula and G. murinus are rather meat-eaters. It can be concluded that food niches, especially of the two European dormice, are separate and thus in natural conditions they do not compete strongly for food resources.

6

Nestbox grids in population studies of the common dormouse [Muscardinus avellanarius L.]: methodological aspects

67%

Juskaitis R.

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nr 3

EN

Two different nestbox grids have been used for studies of the common dormouse (Muscardinus avellanarius L.) populations: high-density nestbox grids in small plots (e.g. 25–30 boxes ha⁻¹ in 1 ha plots) and lowdensity nestbox grids in large plots (e.g. 4 boxes ha⁻¹ in areas of 60 and 85 ha). The present study aimed to compare efficiency and suitability of 25 × 25 m and 50 × 50 m nestbox grids for studies of the common dormouse population, and to show limitations of small study plots in dormouse studies. Live trapping of dormice within nestbox grids proved that all dormice captured used nestboxes placed in both 25 × 25 m and 50 × 50 m grids. Regular control of nestboxes placed in the 25 × 25 m grid gave an opportunity to register all adult dormice living in the study site during shorter periods, and average dormouse capture rate was significantly higher compared to the 50 × 50 m grid. However the 25 × 25 m nestbox grid had one substantial drawback: high nestbox density (16 boxes ha⁻¹) increased environment carrying capacity for dormice in the forest, where natural hollows were almost absent. In consequence, adult dormouse density increased two to four-fold, while their home range sizes decreased by about half. Dormice are distributed irregularly in large forest areas, and the results obtained in small study plots may not reflect the average characteristics of the population. Some results obtained in small study plots (e.g. density, mortality) can be overestimated because of dormouse movements and edge effects. Predators, e.g. owls, can catch some dormice and substantially influence the results obtained in small plots. Because of the influence on dormouse population density and other population parameters, high density nestbox grids (e.g. 20 × 20 m, 25 × 25 m) should not be used in dormouse population studies. Small study plots (e.g. 1 ha) are completely unsuitable for estimation of such dormouse population characteristics as survival (mortality) and dispersal.