THE WINTER BIRD COMMUNITY OF RURAL AREAS IN THE PROXIMITY OF CITIES: LOW DENSITY AND RAPID DECREASE IN DIVERSITY

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1 POLISH JOURNAL OF ECOLOGY (Pol. J. Ecol.) Regular research paper Michał CIACH Department of Zoology and Wildlife Management, Forest Biodiversity Institute, Faculty of Forestry, University of Agriculture, 29 Listopada av. 46, Kraków, Poland michal.ciach@ur.krakow.pl THE WINTER BIRD COMMUNITY OF RURAL AREAS IN THE PROXIMITY OF CITIES: LOW DENSITY AND RAPID DECREASE IN DIVERSITY ABSTRACT: The current problem in farmland ecology is the change in the character of rural development in areas neighbouring cities and towns. Progressive urbanization and the predominance of housing estates over agricultural aims led to a change in the bird community. During , a survey of birds wintering within densely populated built-up rural areas was conducted by the line transect method (a total length of 8 km). A total number of 33 species was recorded and the most numerous dominant was the House Sparrow Passer domesticus, which constituted 32 58% of the bird community. The group of dominants and subdominants (which constituted up to 20% of the bird community) included the Yellowhammer Emberiza citrinella and the Rook Corvus frugilegus, and a group of forest and synanthropic species the Great Tit Parus major, the Blue Tit Cyanistes caeruleus, the Blackbird Turdus merula, and the Collared Dove Streptopelia decaocto. The total density varied in subsequent study years from 57.4 to 87.5 ind. 10 ha 1 and was approximately twice lower than in other rural regions studied in Poland. A significant decrease in the wintering birds diversity index was recorded through the study period. The explanations for this could be in the character of villages in the proximity of builtup city areas. This has rapidly changed in recent years, and nowadays agricultural management in the region is discarded. As a result, farmlands of the region almost entirely lost their agricultural character, notably becoming a residential and recreational backup for cities. The villages neighbouring cities and towns are developed into suburban-like areas, where housing estates predominate over agricultural aims. Future consequences of these changes are far-reaching for farmland biodiversity and ecology. The decrease in species diversity and evolution into urban-like bird communities is the most probable scenario. KEY WORDS: bird community, winter, agriculture, farmland, urbanization, rural habitat 1. INTRODUCTION Birds in rural areas are particularly interesting in the context of transition in agriculture and the farmland landscape. Dynamic changes in agricultural policy in Poland are especially noticeable in recent years after accession to the European Union (Mickiewicz and Mickiewicz 2011). The changes in agricultural management include progressive land aggregation, development of extensive farms, intensification of crop production, and the disappearance of traditional holdings. This inevitably leads to changes in species composition and bird number (Donald et al. 2001, Donald et al. 2006, Voříšek et al. 2010). Contributions to the description of characteristics of birds wintering in farmlands are journal 29.indb :07:03

2 194 Michał Ciach more scarce than those referring to the breeding period (Atkinson et al. 2002). With a total lack of synthesis or more advanced ecological analyses, until now, birds wintering in built-up rural regions of Poland were not commonly studied (see review in: Tr y- janowski et al. 2009). This is surprising due to the fact that birds living close to human settlements constitute a particularly useful object of research. But more importantly, this group of birds allows for a screening test of farmland biodiversity dynamics. Unfortunately, the lack of systematic research in rural regions does not enable to follow the evolution of bird communities with respect to changes in agriculture and the farmland landscape. An important problem which so far has not been among those commonly studied is the change in the character of the countryside neighbouring the city agglomerations and towns (Tr yjanowski et al. 2009). In many rural regions, residential and recreational aims are beginning to predominate. Progressive urbanization and predominance of housing estates over agricultural aims may influence bird communities (Kluza et al. 2000, McKinney 2006). However, contributions to the characteristics of birds wintering in farmlands, which are losing their former agricultural functions, are very scarce. The aim of this paper is to characterize the winter bird community of built-up rural regions in the specific conditions of proximity to city agglomerations. It was hy pothesized that the winter bird community of the study area will differ from strictly agricultural rural regions of Poland in terms of species composition and bird density. Moreover, it was presumed that the bird diversity index will decrease during the study period. 2. STUDY AREA AND METHODS During , a survey of birds wintering in built-up rural regions was conducted by the line transect method (Bibby et al. 1992). The marked transect, with a 100 m fixed belt width (50 m on each side), had a total length of 8 km, and included the characteristic structure of villages (houses, barns, sheds, livestock infrastructure, yards, orchards, and gardens). It ran through the Czech Republic Silesian agglomeration Study area Fig. 1. The location of study area. Bielsko-Biala Slovakia 20 km group of villages in the north-western part of the Kotlina Żywiecka region (southern Poland) and had a total area of 80 ha. Between 25 December and 1 January, a single survey was conducted in each of the study years. The average walking speed was 2 km h 1, and depending on the number of birds, varied from 1 km h 1 to 3 km h 1. The transect was surveyed between 10 a.m. and 2 p.m. in suitable atmospheric conditions. Built-up areas of surveyed villages were surrounded by a mosaic of meadows, and to a lesser extent, abandoned and arable fields. The study area neighboured the Bielsko-Biała town (distance ca. 10 km, population ca. 0.3 million people) and the Silesian agglomeration (distance ca. 60 km, population ca. 2.7 million people) in southern Poland (Fig. 1). In recent years, the studied area has been losing its agricultural character, notably becoming a residential and recreational backup for the above mentioned city population. Bird abundance was presented as a number of individuals per 10 ha. Dominance in the bird community and the Shannon-Wiener diversity index were calculated for each of study years. The inter-year species composition similarity (Sørensen s index QS, in %) and dominance similarity (Renkonen s index Re, in %) were calculated. For inter-site comparison of bird communities, the published results from other rural regions of journal 29.indb :07:03

3 Wintering birds of rural areas near cities 195 Table 1. Species composition, density (D ind. 10 ha 1 ) and dominance (%) of birds wintering in villages of the study region (Kotlina Żywiecka, S Poland) in , studied by the line transect method in a total area of 80 ha (+ value less than 1%). Species D % D % D % D % D % D % Passer domesticus (L.) Parus major L Emberiza citrinella L Corvus frugilegus L Turdus merula L Cyanistes caeruleus (L.) Streptopelia decaocto (Frivaldszky, 1838) Turdus pilaris L Garrulus glandarius (L.) Carduelis chloris (L.) Corvus cornix L Pica pica (L.) Carduelis spinus (L.) Poecile palustris (L.) Periparus ater (L.) Dendrocopos major (L.) Troglodytes troglodytes (L.) Buteo buteo (L.) Phasianus colchicus L Falco tinnunculus L Corvus corax L Passer montanus (L.) Accipiter nisus (L.) Corvus monedula L Pyrrhula pyrrhula (L.) Poecile montanus (Conrad, 1827) Sitta europaea L Fringilla coelebs L Fringilla montifringilla L Coccothraustes coccothraustes (L.) Turdus viscivorus L Regulus regulus (L.) Carduelis carduelis (L.) Total journal 29.indb :07:03

4 196 Michał Ciach Poland were used built-up (Dombrowski 2001, Kot 2004; Man i arsk i 2004, Tr y- janowski et al. 2009). For inter-site similarity indexes, the total number of species and total dominance recorded in were used (Table 1). Statistical procedures were performed using Statistica 8.0 software (St ats of t 2008) according to recommendations by Z ar (1999). 3. RESULTS During the years in villages of the study region (Kotlina Żywiecka), a total number of 33 wintering bird species was recorded. The number of species varied from 17 to 23 (mean = 20.2, ±2.48 SD) in subsequent study years, and only nine species were recorded in each of the study years (Table 1) However, inter-year species composition similarity (QS = 62 87%) was distinct (Table 2). The most numerous dominant was the House Sparrow Passer domesticus, whose dominance in the winter bird community v aried from 32 to 58%. The group of dominants also included the Great Tit Parus major (from 9 to 14%), the Yellowhammer Emberiza citrinella (from 5 to 20%), and the Rook Corvus frugilegus (from 0% to 16%). A group of sub-dominants included the Blackbird Turdus merula, the Blue Tit Cyanistes caeruleus, and the Collared Dove Streptopelia decaocto, which had lower dominance (from 2 to 8%), but occurred in each of the study years. Other species had a lower frequency and/or did not reach significant dominance in the community (Table 1). Inter-year dominance similarity (Re = 66 89%) was distinct (Table 2). The total density varied in subsequent study years from 57.4 to 87.5 ind. 10 ha 1 (Table 1). The density of the most numerous House Sparrow varied from 21.8 to 41.1 ind. 10 ha 1. The density of dominant species (the Great Tit, Yellowhammer, and Rook) did not exceed 14.0 ind. 10 ha 1. The density of subdominant species (the Blackbird, Blue Tit, and Collared Dove) did not exceed 7.4 ind. 10 ha 1. Other typical farmland species did not reach high density (the Tree Sparrow Passer montanus, the Greenfinch Carduelis chloris). The Shannon-Wiener diversity index of birds wintering in villages of the study region decreased significantly in (Spearman s rank correlation coefficient: r s = 0.94, P = 0.005) (Fig. 2). The bird density recorded in the subsequent winters of in villages of the study region (Kotlina Żywiecka) was significantly lower than recorded in other rural regions of Poland (Fig. 3, Mann-Whitney U Test: Z c = 2.65, P = 0.008). Inter-site species composition similarity was rather distinct (Table 3) and did not differ from inter-year species composition similarity in the study Shannon-Wiener H index ) Density (ind. 10 ha N=6 N= Study region Other rural regions Fig. 2. The Shannon-Wiener diversity index of birds wintering in the study region (Kotlina Żywiecka, S Poland) in Fig. 3. Median values (with quartiles and ranges) of wintering bird density recorded in the study region (Kotlina Żywiecka, S Poland) and other rural regions of Poland. journal 29.indb :07:03

5 Wintering birds of rural areas near cities 197 Table 2. Inter-year species composition similarity (Sørensen s index QS, in %) and dominance similarity (Renkonen s index Re, in %) of birds wintering in the study region (Kotlina Żywiecka region, S Poland) in QS Re Table 3. Inter-site species composition similarity (Sørensen s index QS, in %) and dominance similarity (Renkonen s index Re, in %) of birds wintering in the study region (Kotlina Żywiecka region, S Poland) in and other rural regions of Poland. Kotlina Żywiecka region Rural regions of Poland (present study) QS Re Świętokrzyskie region (Umianowice village) southern Poland (Maniarski 2004) Wielkopolska region (Tworzanice village) western Poland (Tr yjanowski et al. 2009) Pojezierze Łęczyńsko-Włodawskie region eastern Poland (Kot 2004) Wysoczyzna Siedlecka region eastern Poland (Dombrowski 2001) Wielkopolska region (Wojnowice village) western Poland (Tr yjanowski et al. 2009) region (Mann-Whitney U Test: Z c = 1.48, P = 0.14). Inter-site dominance similarity was rather vague (Table 3) and was significantly lower than inter-year dominance similarity in the study region (Kotlina Żywiecka) (Mann- Whitney U Test: Z c = 3.23, P = 0.001). 4. DISCUSSION The winter bird community of rural regions which lost their agricultural character is characterized by high dominance of the House Sparrow and domination or sub-domination of the Yellowhammer and Rook, and a group of forest and synanthropic species (the Great Tit, Blue Tit, Blackbird, and Collared Dove). Having high density and/or high frequency, this small group of species formed the core of the community. Other species had lower frequency and/or did not reach significant dominance and density. However, high inter-year species composition and dominance similarities indicate a distinct winter bird community of rural developments of the study region. Compared to other strictly agricultural rural regions of Poland, similar species composition along with different domination of species is noticeable (D ombrowski 2001, Kot 2004, Maniarski 2004, Tryjanowski et al. 2009). This indicates different community structure in rural areas which lost their agricultural character in the proximity of cities. The total bird density in the studied region varied in subsequent study years, however it was approximately twice lower than in other strictly agricultural areas of Poland (Tr yjanowski et al. 2009). It has resulted from the low density of seedeaters, mainly the dominant House Sparrow and the rare Tree Sparrow, which strongly influenced the total density. The dominance and density of forest and synanthropic species was relatively high. Among these was the Blackbird, which regularly winters in cities, being rare in other natural or semi-natural habitats of the country (Tomiałojć and Stawarczyk 2003). The most tempting explanations for this specific avifauna is the character of villages in the proximity of city areas. This has been journal 29.indb :07:03

6 198 Michał Ciach changing in recent years, especially after Polish accession to EU in 2004, and nowadays agricultural management in the region is discarded. Both the number of livestock kept and crop cultivation are scarce. As a result, farmlands of the region almost entirely lost their agricultural character, notably becoming a residential and recreational backup. Along with changes in the character of farmlands neighbouring the cities, a decrease in number of typical farmland species (the Grey Partridge Perdix perdix, the Tree Sparrow, the Corn Bunting Emberiza calandra, and the Greenfinch), and a simultaneous increase in number of forest and synanthropic species (the Great Tit, Blue Tit, Blackbird, and Collared Dove) will most likely be recorded. The consequence of disappearing agricultural production is a decrease in food availability. Traditional livestock rearing and crop cultivation were the main food resources for wintering birds. Nowadays, in farmlands neighbouring cities, birdfeeders are the main food source, thus birds strongly depend on humans as food providers. Moreover, fruits left in gardens, which are not intended for crop production, offer a good food base for several species. Such sources are known for sustaining biodiversity in urban environments (Evans et al. 2011). Species richness peaks at intermediate levels of development and decreases with a high level of urbanization (Blair 1999, Clergeau et al. 1998, Melles et al. 2003). This spatial pattern in the presented study became a process in a relatively short study period, when the decline in bird diversity was significant. Former, traditional uses of farmlands, particularly those located close to city agglomerations, now undergo drastic transformation. Abandonment of agricultural production, along with simultaneous rapid urbanization for housing and recreational purposes, leads to the changes in avifauna occurring in rural terrains. Located near the Bielsko-Biała town and the Silesian agglomeration, farmlands of the study region (Kotlina Żywiecka) have undergone intensive transformations in recent years. Mixed farming systems with abundant woody edge habitats and crop heterogeneity in the farmed landscape retain high avian species richness on Polish farmland (Tr y- janowski 1999, Sanderson et al. 2009). However, total abandonment of crop production and livestock rearing, along with simultaneous housing estate development (gardens, flower beds, hedgerows, non-native trees and shrubs) led to significant change in the rural character of the land. Traditional Polish farmland in the proximity of densely populated and urbanized areas, facing a shift in its functioning, will not maintain high biodiversity. Agri-environment schemes, known to have a positive effect on farmland biodiversity (Kleijn et al. 2006), seem to be not applicable in this case. People, commonly employed in cities, are no longer involved in agricultural production. Villages neighbouring cities are changed into suburban-like areas, where housing estates predominate over agricultural uses. In general, the change in the character of the Polish countryside is a reality (Bański 2006), strongly affecting the bird communities. Future consequences of these changes are farreaching for farmland biodiversity and ecology (B enton et al. 2003). Due to the scarce research and lack of data, many methods of predicting (Sutherland 2006) are not possible to apply in this case. However, the further decrease in biodiversity and changes in trends of species composition into an urbanlike community is the most probable scenario in central and eastern European farmlands. 5. REFERENCES Atkinson P.W., Fuller R.J., Vickery J.A Large-scale patterns of summer and winter bird distribution in relation to farmland type in England and Wales Ecography, 25: Bański J Geografia polskiej wsi [G e- ography of Polish countryside] Polskie Wydawnictwo Ekonomiczne, Warszawa, 220 pp. (in Polish). Benton T.G., Vickery J.A., Wilson J.D 2003 Farmland biodiversity: is habitat heterogeneity the key? Trends Ecol. Evol. 18: Bibby C.J., Burgess N.D., Hill D.A Bird census techniques Academic Press, London, 257 pp. Bla ir R.B Birds and butterflies along an urban gradient: surrogate taxa for assessing biodiversity? Ecol. Appl. 9: Clergeau P., Savard J.-P.L., Mennechez G., Falardeau G Bird abundance journal 29.indb :07:03

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