Annual dynamics of bird communities in urban parks in Lviv, Ukraine: preliminary ana­lysis of diversity and composition variability

Abstract

Species and numeric composition of bird communities were analyzed in parks of Lviv based on results of monthly censuses on 20 linear transects on eight study plots. During the year, 79 bird species that belong to eight taxonomic orders were registered Birds’ diversity was assessed by species number and Simpson index and it varies throu­ghout the year and denotes higher level during the breeding season. Similarly, birds’ density is the highest in breeding season, but it also has a less expressed peak in winter period. This shows that biotopical preferences to be presented in urban greenery of parti­cular birds are especially notable only while breeding, but in non-breeding season those birds stay resident in scale of the city though disperse in other habitat types. Between-months, stability of species composition (assessed by Jaccard index) and numeric composition (by Bray–Curtis index) was analyzed. Communities were the most stable during the breeding season as birds are related to their nesting sites. According to zoogeographic classification, European species dominate during all months. Siberian, Transpalearctic and Medite­rra­nean species also play role in forming of the community structure. The main food resour­ces type which compensates energy demands of birds during the breeding season is inver­te­brates; this shows the importance of birds in controlling the abundance of invertebrates in urban ecosystems. Seeds are also important food resour­ce types, especially during the non-breeding period. Abundance variability of part of spe­cies is related with season. Three main groups of these species were defined: breeding migrants (mainly songbirds such as Fringilla coelebs, Erithacus rubecula, Sylvia atricapilla, Phylloscopus collybita etc., also Columba palumbus), wintering migrants (Spinus spinus, Turdus viscivorus, Bombycilla garrulus, Pyrrhula pyrrhula) and residents (typical synanthropic species whose numbers vary: Turdus merula, Coccothraustes coccothraustes, Troglodytes troglodytes, Cyanistes caeruleus etc.). The last ones, probably, migrate in non-breeding seasons to other habitat types, that can explain their abundance variability.

Keywords

• seasonal variation
• urban ecosystems
• synanthropic species
• bird species composition
• urban forest
• bird community