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1

Age-related fragmentation of mitochondrial DNA associated with oxygen damage

100%
Ozawa T.
Biotechnologia
|
1996
|
nr 4
2

The influence of residual tree patch isolation on habitat use by bats in central British Columbia

86%
Swystun M. B., Psyllakis J. M., Brigham R. M.
Acta Chiropterologica
|
2001
|
tom 03
|
nr 2
One forest management practice associated with logging aimed at contributing to the maintenance of biodiversity is to leave residual tree patches within cut blocks. Using Anabat bat-detectors we monitored bat activity along residual tree patch edges and clear-cut edges associated with recent clear-cuts in north-central British Columbia. We tested two hypotheses, (1) relative bat activity would be higher on the clear-cut edge than the residual patch edge, (2) relative bat activity would decrease on the residual patch edge with increasing isolation from the clear-cut edge. We sampled six pairs of edges and found no significant difference in bat activity between patch and clear-cut edges. We found a significant but non-linear relationship between relative bat activity on the patch edge with increasing patch isolation. Bat activity on the residual patch edge was highest at intermediate levels of patch isolation and lower both at patch edges close to, and highly isolated from the clear-cut edge. We postulate that the reason for this relationship is that patches act as windbreaks collecting high densities of insects making them good foraging areas but this benefit is coupled with an increased risk of prédation associated with crossing large gaps. At low levels of patch isolation bats may perceive residual patches and adjacent clear-cut edges as a continuous foraging area and thus, bat activity is evenly distributed throughout both habitats. In summary, our data indicate that patches provide localized habitat for foraging bats, however, foraging areas are only one habitat component required by bats and it remains uncertain if patches also offer suitable roosting opportunities.
3

Dispersal of common dormice Muscardinus avellanarius in a habitat mosaic

86%
Buchner S.
Acta Theriologica
|
2008
|
tom 53
|
nr 3
In the eastern part of Saxony (Germany), common dormiceMuscardinus avellanarius (Linnaeus, 1758) were found in very small woods (average area of 10 woods was 2.9 ± 1.4 ha) isolated within agricultural fields for more than 100 years (average distance to the next, larger wood 268 ± 84 m). Dormice reproduced even in wood islands smaller than two hectares. Altogether 6 marked dormice were recorded migrating across the open landscape. Of these, 5 were juveniles. Minimum and maximum distances in treeless areas between points of capture and recapture were 250 and 500 m respectively. These migrations over open ground seem to be rare but normal events and explain the presence of common dormice in very small patches of woodland in habitat mosaics.
4

Vegetation landscape analysis due to land use changes on arid lands

72%
Manjarrez-Dominguez C., Pinedo-Alvarez A., Pinedo-Alvarez C., Villarreal-Guerrero F., Cortes-Palacios L.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 2
Fast land use changes have strongly affected arid and semi-arid regions at a global scale, affecting food security of the inhabitants of these regions. This study evaluated the fragmentation degree in the Chihuahua´s desert region of Mexico by using data from the Landsat TM sensor. Nine scenes, taken with Landsat TM5 sensor from the years 1990, 2000, and 2012, were used for the analysis. The coverage of seven land uses (grasslands, shrubland, croplands, sandy desert vegetation, forest, water bodies, and urban areas) was obtained under supervised classification techniques and the accuracy level was evaluated through the Kappa multi-varied discrete index. The classification showed a good reliance level having global accuracies of 93, 93.2 and 90.3% for the years 1990, 2000 and 2012, respectively. The fragmentation analysis showed an increase in the number of patches, an indicator of the ecosystem degradation process. The patches number increased from 8,354.23 in 1990 to 9,658.36 in 2000 and to 11,469 in 2012. Simpson and Shannon diversity indexes proved a clear fragmentation process. During the period of 1990−2012, grasslands were the most affected vegetation type with a reduction of 30.7% in its area. Such reduction was mainly attributed to invasions of shrubland communities and to an increase in cropland areas.
5

Effect of particle size of fragmented wheat on energy requirements in the process of extrusion

72%
Skonecki S., Laskowski J.
Teka Komisji Motoryzacji i Energetyki Rolnictwa
|
2010
|
tom 10
6

Rozdrabniarka do drewna pouzytkowego o duzej wydajnosci

72%
W K.
Biuletyn Informacyjny Ośrodka Badawczo-Rozwojowego Przemysłu Płyt Drewnopochodnych w Czarnej Wodzie
|
1998
|
tom 39
|
nr 4
304-305
7

The influence of fragmentation on the growth of Elodea canadensis Michx. in different light conditions

72%
Mielecki M., Pieczynska E.
Polish Journal of Ecology
|
2005
|
tom 53
|
nr 2
Plant fragments are commonly noticed in a wide range of freshwater environments. However, data on their further growth remain very scarce. The post-fragmentation growth of Elodea canadensis was analysed in a laboratory experiment in which plants were exposed to different light conditions ranging from 3 to 30 µmol m⁻² s⁻¹. The growth of whole plants (12cm) and fragmented (cut) shoots (apical fragment of 3 cm and middle and lower fragments of 4 and 5 cm respectively) was analysed over 33 days (with measurements of weight and length after 11, 21 and 33 days). In all light treatments both cut and whole plants grew. The growth rates were found to vary greatly over the exposure period. During the first 11 days, whole plants or the fragments thereof exhibited the greatest increases in biomass and length in all light treatments. Following further exposure under no shade and moderate shade, the growth of all plants, although still significant, was visibly more limited. Under conditions of a 90% shade level, 11 days of exposure left both whole and cut plants still alive, but incapable of any further significant increase in length or biomass. Generally, in high light levels cut plants grew more intensively, while in conditions of the most intensive (90%) shade, no differences in growth of these groups of plants were noted or the growth of cut plants was limited to a greater extent. A greater number of new lateral shoots were noted in cut plants than in whole plants. Even in conditions of low light characterized by the poor growth of plant fragments the production of new shoots was still possible. In general, fragments of Elodea canadensis were found to be very efficient at surviving and regenerating under a wide range of light conditions.
8

Analysis of chosen factors influencing the late recognition of fragmentation of the medial coronoid process in dogs

72%
Komsta R.
Bulletin of the Veterinary Institute in Puławy
|
2006
|
tom 50
|
nr 3
9

Factors shaping European rabbit abundance in continuous and fragmented populations of central Spain

72%
Virgos E., Cabezas-Diaz S., Malo A., Lozano J., Lopez-Huertas D.
Acta Theriologica
|
2003
|
tom 48
|
nr 1
This study analyses differences in European rabbitOryctolagus cuniculus (Linnaeus, 1758) abundance between fragmented and continuous populations and the relative importance of habitat structure (micro- and macrohabitat) and isolation in determining the abundance pattern in fragmented and continuous areas of central Spain. The species was mainly restricted to mediterranean vegetation habitat. In fragmented areas, rabbit abundance was linked to scrubland cover but was not correlated to pasture/cropland cover. The model explained very little of the observed variance. Distance to continuous populations did not improve the model. Stochastic phenomena or unmeasured factors (predation level, soil type) could be acting in this context. Rabbits were more abundant in continuous areas than in fragmented ones. In continuous areas, rabbit abundance was associated with mosaics of pastures, scrublands, and croplands. These habitat features are linked to shelter and feeding requirements of rabbits. The model explained an important part of the observed variance. This supports that management and conservation strategies should be based on the landscape pattern in each situation.
10

Bat frugivory in a remnant of Southeastern Brazilian Atlantic forest

58%
Aguiar L. M., Marinho-Filho J.
Acta Chiropterologica
|
2007
|
tom 09
|
nr 1
Knowledge of bat diets may be important for the conservation of small Atlantic Forest fragments because these animals play an important role in seed dispersal and natural recovery of tropical forests. The ‘Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala’ (RPPN-FMA) is a 886-hectare Atlantic forest fragment consisting of a mosaic of distinct successional phases resulting from logging and natural causes, in the state of Minas Gerais, Brazil. We collected 216 fecal samples containing blood, arthropods, pollen-nectar, vegetation (leaflets and fruit peel), fruit pulp (fibers and juice) and seeds, from 18 bat species at the RPPN-FMA. Piperaceae, Solanaceae, Cecropiaceae, and Guttiferae were the most important food resources for frugivorous bats at RPPN-FMA. Piper infrutescences were consumed by Artibeus obscurus, A. fimbriatus, Carollia perspicillata, and Sturnira lilium throughout the year, functioning as key species, as already observed for other tropical rainforest sites.
11

Effect od patch size on habitat loss in sedge warblers Agrocephalus schoenobaenus in the Middle Nida Wetlands [southern Poland]

58%
Bielanski W., Solarz W., Zajac T.
Nature Conservation
|
2005
|
tom 61
43-51
12

Rozdrabniarka jednowalowa z zasilaniem poziomym

58%
W K.
Biuletyn Informacyjny Ośrodka Badawczo-Rozwojowego Przemysłu Płyt Drewnopochodnych w Czarnej Wodzie
|
1997
|
tom 38
|
nr 3
160-161
13

The effect of land cover and fragmentation of agricultural landscape on the density of White Stork [Ciconia ciconia L.] in Brandenburg, Germany

58%
Latus C., Kujawa K.
Polish Journal of Ecology
|
2005
|
tom 53
|
nr 4
The aim of the study was to identify landscape properties which are responsible for the large differences in White Stork population densities occurring in an agricultural landscape. The study area covered six plots (308– 1218 km²) in Brandenburg (Germany). They differed in respect to proportions of main landscape components (grasslands, crop fields, woodlands, parks and gardens, built-up areas), to degree of fragmentation of grasslands and crop fields and to proportions of different grassland types (moist meadows, slightly moist pasturelands, dry grasslands, persistent nitrophilous ruderal communities, herbaceous perennials and intensively used sown grassland). The correlation coefficients between the Stork density and proportions of main landscape components were small (|rs |<0.7) and insignificant (P>0.15) but the Stork density was positively related to proportion of intensively used sown grasslands. However, the greatest part of variation in Stork density could be explained by the fragmentation of grasslands and crop fields. Stork density was positively correlated with density of crop field patches as well as with grassland edge density. The spatial distribution of these patches was not important. Our results suggest that at a moderate proportion (ca. 10%) of grasslands, composition and high fragmentation of these habitats are vital for white storks.
14

Differential mobility in two small phyllostomid bats, Artibeus watsoni and Micronycteris microtis, in a fragmented neotropical landscape

58%
Albrecht L., Meyer C. F. J., Kalko E. K. V.
Acta Theriologica
|
2007
|
tom 52
|
nr 2
To assess the influence of habitat fragmentation on small bats, we determined home range size and mobility of the frugivorousArtibeus watsoni Thomas, 1901 and the gleaning insectivorousMicronycteris microtis Miller, 1898 by radiotracking on different-sized islands (2.7–17 ha) in Lake Gatún, Panamá. The two species differed in their response to fragmentation. Home range size was highly variable in the five trackedA. watsoni, ranging from 1.8 to 17.9 ha with a mean of about 9 ha. Some individuals flew regularly between islands and/or the mainland, thereby traversing up to 180 m of open water. In comparison, home ranges of threeM. microtis were with about 3.8 ha only half as large. All ofM. microtis exhibited sedentary foraging behaviour and did not cross open water, suggesting that they might persist at least on some of the islands as resident populations. Our findings are consistent with radiotracking data from a previous study and indicate that small habitat patches are still used by small bats, provided the degree of isolation is low and that sufficient resources and larger habitat patches exist in close vicinity, potentially acting as additional feeding grounds and source populations.
15

Fragmentacja na rynku prasowym

51%
Zabinski R.
Marketing i Rynek
|
2010
|
tom 17
|
nr 04
25-31
16

Effects of fragmentation and isolation on genetic variability of the Italian populations of wolf Canis lupus and brown bear Ursus arctos

51%
Randi E.
Acta Theriologica. Supplement
|
1993
|
tom 38
|
nr 2
During the last centuries many West European populations of wolf Canis lupus Linnaeus, 1758 and brown bear Ursus arctos Linnaeus, 1758 have been extirpated from most of their former ranges. Isolated populations of wolves (about 300 - 400 animals) and brown bears (about 80 - 100 animals) actually survive in the Italian Apennines, while very few (5 - 10) brown bears remain in the Italian eastern Alps. We have investigated the consequences of isolation, demographic decline, and random drift on genetic variability of the Italian populations of wolf and brown bear using restriction site analysis and nucleotide sequencing of portions of the mitochondrial genome. The studied sequences were homogeneous within-populations of both species, but there was a fixed difference in mtDNA between brown bears form the Alps and from the Apennines. Random drift since the time of isolation is a plausible explanation for both results. These findings suggest that wolves and bears have small effective population sizes and, thus, they will continue to loose genetic variability by random drift in the near future. Conservation efforts should be directed towards an increase of the annual growth rates of these populations. The individualization of discrete phylogeographic units in the brown bear suggests to manage them separately in order to preserve the existing gene diversity among populations.
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