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Granivory of birds and seed dispersal : viable seeds of Amaranthus retroflexus L. recovered from the droppings of the Grey Patridge Perdix perdix L.

Orłowski G., Czarnecka J.

Polish Journal of Ecology

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2009

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Vol. 57, nr 1

191-196

EN

The droppings of the Grey Partridge Perdix perdix L. wintering on a set-aside field were found to contain 99.3% of Amaranthus retroflexus and 0.7% of Chenopodium album seed coat fragments. A bird consumed on average 3008 ([plus or minus] 95% CL = 2699-3317) weed seeds per 1 g of droppings. The excreted seed coat remnants made up c. 21% of the swallowed seed mass. Approximately 0.3% of the ingested seeds passed undamaged through the gut. The number of undamaged seeds in the droppings was not significantly correlated with the weight of droppings and the amount of the excreted sand grains, seed coat fragments and other plant parts. After over 1.5 years of storage, 3 out of 18 sown undamaged seeds of A. retroflexus germinated. The average germination time of the excreted seeds was 10 days, while for the fresh ones it amounted to 8.5 days. Our results shows that the Gray Partridge is poor seed disperser and it play important role as predator of A. retroflexus seeds.

2

Species composition and habitat correlates of amphibian roadkills in different landscapes of southwestern Poland

Orłowski G., Ciesiołkiewicz J., Kaczor M., Radwańska J., Żywicka A.

Polish Journal of Ecology

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2008

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Vol. 56, nr 4

659-671

EN

During four seasons (years 2000-2004) on 52.3 km of roads with traffic frequencies ranging from 350 to 10 500 vehicles day[^-1] and crossing diverse habitats in five regions of south-western Poland 3 742 roadkills from 10 amphibian species were recorded. The most frequent road killed species was common toad Bufo bufo (52% of all roadkills), followed by common frog Rana temporaria (12%), green toad Bufo viridis (11%) and moor frog Rana arvalis (3%). For all surveyed roads the roadkill density was positively correlated with the share of woods and the area of ponds. Actual traffic density was a poor predictor of the number of amphibian roadkills in large landscape scale (all surveyed roads). To assess the factors affecting the number of amphibian roadkills in the small landscape scale the Generalized Linear Models (GLZ) were performed between the number of casualties and five habitat variables (area and number of ponds, share of built-up area, open countryside and woodland) for four circular buffer zones (<200 m, <300 m, <400 m, <500 m) around each of the 100-meter sections within 1.8 km of road crossing an area rich in water bodies. The most important variables in GLZ models were the area and number of ponds. These predictors had statistically significant impact on number of roadkills within buffer zones <500 m (area of ponds) and <400 m (number of ponds).

3

Avian responses to undergrowth removal in a suburban wood

Orłowski G., Martini K., Martini M.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

487-495

EN

The breeding (in 1991-1996) and wintering (1991/1992-1993/1994) avian community were surveyed in a suburban wood (29.27 ha) in Wrocław city (SW Poland). The 1992 breeding season began together with a drastic clearance of the compact undergrowth with the use of heavy machinery. A slump of abundance of the species nesting on the ground and small shrubs ([less than or equal to]1.5 m) followed, coupled with some modifications to their breeding behaviour, such as clustering of several singing males on the remaining bushes (Blackcap Sylvia atricapilla L.) and nesting in the piles of cut branches (Blackbird Turdus merula L.). As a result of the removal of 52% of the whole undergrowth the density of species nesting on the ground and small shrubs in 1992 was by 26% lower than in 1991 (decrease from 61.8 to 46.3 pairs 10 ha[^-1]). After 1993 a spontaneous regeneration of the bushy vegetation took place, with the ground and shrub-nesting species. density recovering to 49.4 pairs 10 ha[^-1] in 1996. After 1991 the park was colonized by 9 new hole-nester species, which was accompanied by the increase of density of this group (from 21.9 in 1991 to 37.9 pairs 10 ha[^-1] in 1996). Throughout the entire study period a slight rise of density of birds nesting in tree canopies was visible (21.3 pairs 10 ha[^-1] in 1991 and 33.8 pairs 10 ha[^-1] in 1996). A year after the shrub clearance the wintering bird abundance was significantly lower (half of the previous numbers), with plant-eaters and insectivores hardest hit, especially Great Tit Parus major L. (average number of inidividuals per one count amounted to 59.2 in 1991/1992 and 21.9 in 1992/1993) and Blue Tit Parus caeruleus L. (respectively 37.0 and 16.0 ind.). An adequate timetable of vegetation clearance must be set up in the course of any decision-making process regarding green areas management to ensure the environmental issues are addressed properly.

4

Heavy metal concentrations in the tissues of the Black-headed Gull Larus ridibundus L. nesting in the dam reservoir in south-western Poland

Orłowski G.

Polish Journal of Ecology

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2007

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Vol. 55, nr 4

783-793

EN

Concentrations of heavy metals (lead, cadmium and copper) were measured in several tissues (pectoral muscle, liver, kidney, lung, femur, brain and feather) of the fledglings and adults of black-headed gull Larus ridibundus L. collected in breeding colony (c. 2000 pairs) in south-western Poland (Mietkowski Reservoir; 980 ha). Fourteen birds (5 fledglings and 9 adults) were collected shortly after death (unknown reason of mortality) in June and July 2003. The highest mean ([plus or minus] 1 SD) level of lead was demonstrated in femur samples (42.32 [plus or minus] 31.42 [micro-]g g[^-1] dry weight), whistle the lowest one, in muscle (3.59 [plus or minus] 0.57 [micro-]g g[^-1] d.w.). The highest and the lowest levels of cadmium were in turn demonstrated in kidney (5.51 [plus or minus] 4.90 [micro-]g g[^-1] d.w.) and in muscle (0.31 [plus or minus] 0.22 [micro-]g g[^-1] d.w.), respectively. Liver was the organ with the highest copper accumulation (29.22 [plus or minus] 13.56 [micro-]g g[^-1] d.w.), whereas the lowest amounts of the element were found in femur samples (2.79 [plus or minus] 1.01 [micro-]g g[^-1] d.w.). Among 21 pairs of tissues in which metal concentrations were compared, only in eight cases statistically significant differences between fledglings and adults were recorded. The accumulation of heavy metals in organs of black headed gull was up to c. 81-fold lower than in bottom sediments of this reservoir.

5

Species composition of woody vegetation of three types of mid-field woodlots in intensively managed farmland (Wrocław Plain, South-Western Poland)

Orłowski G., Nowak L.

Polish Journal of Ecology

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2005

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Vol. 53, nr 1

25-36

EN

The paper presents the results of studies devoted to woody species composition in three types of mid-field woodlots (N=183), located on the area of 5480 ha in the intensively managed agricultural landscape of Wrocław Plain (Lower Silesia, south-western Poland). The woodlots studied were divided into mid-field clumps (n=74), water-edge hedgerows (n=75) and avenues (n=34). In general, in the three types of woodlots 77 woody plant species were found. To the most common species (50% frequency in all the woodlots) belonged: elder (Sambucus nigra), single-neck hawthorn (Crataegus monogyna), blackberry (Rubus spp.) and blackthorn (Prunus spinosa). For 21 species, statistically significant differences between frequency of occurrence in water-edge hedgerows and clumps were found. Ten species differed in frequency of occurrence between water-edge hedgerows and avenues. Differences between clumps and avenues were documented for 15 species. No significant differences were found in the occurrence of species dispersed by wind, animals and water, and between native species and those of foreign origin, in the respective types of woodlots. For the three types of woodlots studied, high statistically significant correlations were found between the size of woodlots (length for water-edge hedgerows and avenues, and area for mid-field clumps) and the number of recorded woody species. Based on the results obtained and literature data the mechanisms of the floristic diversity of mid-field woodlots were discussed.

6

Semi-natural reedbeds as breeding habitat of Bluethroat (Luscinia svecica L.) on sevage farm in Wrocław city (South-Western Poland)

Orłowski G., Sęk M.

Polish Journal of Ecology

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2005

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Vol. 53, nr 1

135-142

EN

In the breeding season of 2004 in sewage sedimentation basin overgrown with semi-natural reedbeds (n=63, total area 113,3 ha, mean area =1.80 (± 3,90) ha, range: 0,018 do 26,54 ha) on a sewage farm (total study area 14,22 km2) in the northern part of Wrocław city (640000 inhabitants, SW Poland) 45 territories of Bluethroat Luscinia svecica cyanecula were found. Territorial birds were detected in 38% of all controlled reedbeds. Up to eight territories were localized in a single reedbed. In at least ten territories (22% of all) the presence of breeding pairs was also recorded. The smallest reedbed occupied by a single male had 0,081 ha and by a pair - 0,204 ha. A high statistically significant correlation was found between the reedbed area, the length of its border and the number of territories it contained. The probability of Bluethroat occurrence in a reedbed was closely related to its size. Even in small reedbeds (<2 ha) it amounted to ca. 35% and it reached 100% at 10 ha. Within particular occupied reedbeds (n=24) the densities ranged from 1,5 to 49,5 (exceptionally 123,4) territories 10 ha-1. The average density (± SD) for all reedbeds (n=63) was 7,6 (± 19,2) territories 10 ha-1, while within the occupied reedbeds (n=24) it amounted to 20,0 (± 27,1) territories 10 ha-1. The Wrocław population of Bluethroat is one of the biggest known breeding concentration of this species not only in western Poland, but probably also in large part of central Europe. So far reports of marked increases of Bluethroat abundance in anthropogenic habitats (after a dramatic decline observed since the end of XIX century) have come mainly from western Europe.

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Habitat use by breeding and wintering Reed Bunting Emberiza schoeniclus L., in farmland of Lower Silesia (SW Poland)

Orłowski G.

Polish Journal of Ecology

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2005

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Vol. 53, nr 2

243-254

EN

Studies on the habitat preferences of Reed Bunting Emberiza schoeniclus L., conducted on an intensively farmed (93% arable land) area (54 km2) of Wrocław Plain (Lower Silesia Province, SW Poland, 17°03' E, 51°02' N) have shown that during the breeding season this species was found mainly in abandoned crop fields profusely overgrown with Tanacetum vulgare, Artemisia vulgaris and Solidago sp. Wintering birds remained in strongly weeded crops (arablehabitats). The presence of breeding pairs (n=37) was recorded within 24 (36%) out the 67 longterm fallows (total area = 336,88 ha, average area = 5,03 (± 10,52 SD) ha, range = 0,19 to 83,53 ha). The field size was the best predictor of the Reed Bunting abundance among the seven landscape variables describing the environmental diversity of a fallow (apart from the field size, these were the lengths of: treebelts, hedges, railvay embankments, roads, ditches and borders with adjacent crop fields). In the model of multiple regression after stepwise forward selection this variable explained as much as 86% of the variance in Reed Bunting abundance in that biotope. Wintering birds (total of 367 specimens) were discovered in 43 (37%) out of the 117 studied fields, comprising seven arable habitats - cereal stubbles, young and old fallows, root crop stubbles, fruit and vegetable crops, bare tilled and winter cereals (average area = 2,81 (± 2,31), range = 0,23 to 12,72 ha). The highest density and frequency (i.e. percentage of one field type where at least one Reed Bunting was recorded) were found in strongly weeded fruit and vegetable crops and in root crop stubbles (with abundant Amaranthus retloflexus, frequency respectively 89 and 64%) in young fallows (with a series of annual weed species, including the abundant Chenopodium album; 77% frequency) and in cereal stubbles (with Chenopodium album and Setaria viridis; 50% frequency). In winter season birds were recorded only in 20% of old fallows. No wintering birds were found in winter cereals, nor in ploughed fields. The large area of root crops in Poland and the related spreading of weeds, such as Amaranthus and Chenopodium, coupled with long-term set-aside may compensate many granivorous birds, wintering in Europe on farmland, for the considerable reduction in their winter food resources, caused by the massive introduction of winter cereals.

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Road mortality of hedgehogs Erinaceus spp. in farmland in Lower Silesia (south-western Poland)

Orłowski G., Nowak L.

Polish Journal of Ecology

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2004

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Vol. 52, nr 3

377-382

EN

The paper presents the results of studies on mortality of hedgehogs Erinaceus spp. on roads in the agricultural landscape of Lower Silesia (south-west Poland). The investigation was carried out in 2001-2003 on a 48.8 km road network. The overall number of hedgehogs found killed was 75. Ninety three percent of all casualties (n=70) was documented in built-up areas. For the whole period of investigation the average number of victims per 1 km road was 1.54, while in 2002 - 0.76. The average number of victims per 1 km road in built-up area was 37 times greater that in undeveloped area (5.4 vs. 0.14 casualties/11 km road). Based on the data obtained, it was calculated with the multiple regression method that hedgehog mortality on the 22 road sections studied in built-up areas was in 90% determined by the level of variation in the mean 24 hour traffic volume and lengths of the road sections.