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1
Content available remote Non-significant trends towards earlier or later arrival date of the Pied Wagtail (Motacilla alba) in N-W Croatia
Dolenec Z.
Polish Journal of Ecology
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2012
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Vol. 60, nr 4
851--854
EN
Over the past century, average global temperature increased by an approximately of 0.6°C and it has been show that global warming has been affecting many biological systems. Recent climate change has influenced birds in many ways. The aim of this work is to present trends in the first arrival date and potential impact of mean monthly temperature on the spring migration of the Pied Wagtail (Motacilla alba) in long-term study in northwestern Croatia (Mokrice rural area). The study was conducted during 1980–2011. The Pied Wagtail is a small, semi-hole nesting, migratory, insectivorous passerine breeding in Europe and Asia (also breeds in Morocco and western Alaska). This study didn’t show that over the research period the Pied Wagtail returned to their breeding sites significantly earlier. This can be explained with the fact that local temperatures for February/March, did not increase significantly (P> 0.05). The change in Pied Wagtail arrivals was very little and advanced 1.47 days (non-significant) over the study period (1980–2011). \\@eng\
2
Content available remote Response of the Blackcap (Sylvia atricapilla L.) to temperature change
Dolenec P., Dolenec Z.
Polish Journal of Ecology
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2010
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Vol. 58, nr 3
605-608
EN
Many authors have demonstrated use of plants and animals as sensitive biomonitors for climate changes. This research was conducted in the Mokrice area (mixed agricultural landscape and small deciduous woods) in northwestern Croatia and studies cover the period from 1979 to 2007. This paper assesses evidence that year and local air temperature changes influence first arrival dates of the migratory passerine Blackcap, Sylvia atricapilla. The mean first arrival date of the Blackcap was 2 April (1979-2007). Correlation between timing of arrivals and year was significant (P <0.001). Blackcap arrival dates have become 9.3 days earlier during the research period (slope of linear regression = -0.32 [plus or minus] 0.01). The relationship between spring temperatures (March-April) and year (P = 0.019), and spring temperatures and timing of arrival (P <0.001) was also significant. This result suggests that Blackcap respond to spring temperatures by earlier arrivalat breeding grounds.
3
Content available remote Long-term trends in timing of breeding of the Barn Swallow Hirundo Rustica L. in Croatia
Dolenec Z., Dolenec P., Kralj J., Kis Novak D.
Polish Journal of Ecology
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2009
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Vol. 57, nr 3
611-614
EN
Climate change is known to have number effects on plants and animals. Several studies have indicated advances in laying dates of birds in the last ca. 40 years, which could be attributed to air temperatures. The research was conducted in the village of Mokrice, a part of the Hrvatsko Zagorje region (northwestern Croatia). We studied the long-term variation in the laying date of Barn Swallow Hirundo rustica in order to examine their breeding phenology in relation to mean spring temperature. The Barn Swallow is a common bird species in the study area. We found a significant correlation between the first laying date and year. The coefficient of regression (slope = -0.36) for Barn Swallows indicates an earlier breeding by 0.36 days per year, or 10 days over the period of the study (1979-2007). Our studies suggested that date of clutch initiation in the studied population is influenced by spring temperatures.
4
Content available remote Impact of local air temperatures on the brood size in starling (Sturnus vulgaris L.)
Dolenec Z.
Polish Journal of Ecology
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2009
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Vol. 57, nr 4
817-802
EN
Many papers over recent years have demonstrated long-term temporal trends in biological parameters that can only be explained by global warming. I examined the long-term trends in the brood size of Starling (Sturnus vulgaris) in Mokrice area (north-western Croatia). I collected data from 1977 to 2007. To investigate the effect of spring temperatures on the brood size, local air temperature was used. The significant correlation (P <0.01) between mean brood size and the year (y = -31.403 + 0.018x) indicates that brood size (mean number of nestlings per nest) increased by 0.018 nestling per year, or 0.54 nestling over the period of the study. Correlation between brood size (mean number of nestlings per nest) and mean spring temperature was also significant (P <0.05) and regression equation (y = 4.162 + 0.07x) indicates that brood size increased by 0.07 nestling per 1[degrees]C. The correlation between mean spring air temperature and research year was significant (P <0.01). This data show that the mean May temperature has been increasing in the study area. We can conclude that Starlings in north-western Croatia are increasing their brood size and that the most likely cause is a long-term increase in spring temperatures.
5
Content available remote Habitat preferences of the Collared Flycatcher, Ficedula albicollis (Temm.) in mountains of continental Croatia
Kralj J., Ćiković D., Dumbović V., Dolenec Z., Tutis V.
Polish Journal of Ecology
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2009
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Vol. 57, nr 3
537-545
EN
Habitat selection of Collared Flycatcher, Ficedula albicollis (Temm.) was studied at three mountains of Continental Croatia covered with oak-hornbeam, beech and coniferous forests. Standard point count technique was used (n = 163). Collared Flycatcher territories were found at 59 points, 17 of them identified as the best territories, with two or more pairs present. Habitat at each counting point was described by the circular plot method. Each counting point was further characterized by the forest type. Differences between the proportions of available and used forest types were tested with [x^2] goodness-offit test. Standardized selection index (B) and 95% confidence limits with Bonferroni correction were calculated. PCA was used to identify the principal sources of variation in the habitat structure. In our study, both forest types and structural characteristics of habitat had effect on the habitat choice of the Collared Flycatcher. The Collared Flycatcher preferred oak and beech forests and strictly avoided pure coniferous stands. The best territories are mostly situated in the pure beech and mixed beech forests. PCA on habitat characteristics produced five components which accounted for 84.3% of the variation in the habitat structure. PC1 and PC3 indicated the presence of coniferous trees while PC2 and PC4 indicated the forest age. The PCA revealed significant relationship between Collared Flycatcher presence and several structural characteristics of habitat: total tree density, densities of small and large trees, shrub density and average tree basal area. The best territories were situated in the forest patches with low number of large trees. Tree density is an important factor for habitat selection in younger forests, but in stands older than 100 years, other factors play more important role in the habitat selection. The Collared Flycatcher avoided forests with dense shrub layer.
6
Content available remote Female biometrical characteristics and egg dimensions of the Starling (Sturnus vulgaris L.) in Croatia
Dolenec Z., Kralj J., Mustafić P., Dolenec P.
Polish Journal of Ecology
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2008
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Vol. 56, nr 3
545-548
EN
Female biometrical characteristics play an important role in the breeding and contribute to breeding success. The size and shape of Starling (Sturnus vulgaris) eggs in relation to female characteristics were examined. The material was collected in northwestern Croatia (Mokrice region) in 2007. Only first clutches were analysed. Egg length averaged 29.7 mm, egg breadth - 21.2 mm, egg volume - 6810 mm[^3] and egg shape index - 1.41. The inter-clutch CV amounted 6% for length, 3% for breadth, 10% for volume and 6% for egg shape index. The mean female body mass was equal to 81.8 g, wing length - 128.6 mm and female condition - 0.64. No significant correlation was found between the female biometrical parameters like body mass, wing length, female condition and egg dimensions (like egg length, egg breadth, egg volume) or egg shape. Egg length was marginally correlated with egg breadth. Female body mass was significantly correlated with wing length.
7
Content available remote Variation in egg dimension of the Tree Sparrow (Passer montanus L.) in north-western Croatia
Dolenec Z.
Polish Journal of Ecology
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2007
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Vol. 55, nr 4
841-845
EN
A nest-box-breeding population of Tree Sparrow was studied during 2004-2005 in the rural area (in locality Mokrice) in northwestern Croatia. The mean egg length was 18.9 mm, egg breadth - 14.1 mm, egg volume - 1937.8 mm[^3] and egg shape index - 1.34. No significant correlation between egg volume and clutch size was found (P> 0.05) and there is no significant difference in those parameters between years of study (2004 and 2005) as well as between successive clutches in the given year. The repeatability of egg dimensions (r = 0-1) of females that bred in an area three times a year was estimated. The egg dimensions are highly repeatable r = 0.78, 0.63, 0.72 and 0.75 for length, breadth, volume and shape index, respectively. The results suggest that in Tree Sparrow population one should expect relatively high heritability of egg dimensions.
8
Content available remote Egg dimensions of the Great Tit (Parus major L.) in Croatia
Dolenec Z., Mrakovčić M., Delić A.
Polish Journal of Ecology
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2005
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Vol. 53, nr 1
143-145
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