Keywords
community ecology
long-term ecological monitoring
Great Cormorant (Phalacrocorax carbo)
ecological succession
Sivash lagoon
Azov Sea wetlands
species turnover
interspecific competition
biodiversity dynamics
How to Cite
Abstract
The Central Sivash region, a unique ecosystem of saline lakes and reed-beds, hosts important colonial waterbird communities. This study analyzes long-term changes (1949–2024) in the breeding bird population on Kitay Island, one of the area’s key islands. Our results reveal a significant ecological restructuring, marked by a pronounced increase in Great Cormorants (Phalacrocorax carbo), which became the dominant species, and a concurrent decline in Yellow-legged Gulls (Larus cachinnans). Total nest numbers peaked in the late 20th century before declining to a lower, stable level. Community analyses identified three distinct succession phases: a gull/tern-dominated assemblage (1950–1980), a cormorant-dominated phase (1990–2010), and a more mixed and diverse recent community. These shifts are interpreted in the context of environmental drivers including habitat change, interspecific competition, predation pressure, and reduced human disturbance. This most recent phase is characterized by a slight reduction in species dominance and an increase in diversity, driven by the arrival of new species. These findings demonstrate profound community turnover and highlight the dynamic response of avian populations to environmental change, providing critical insights for the conservation management of this sensitive habitat.
References
Anderson MJ, Crist TO, Chase JM, Vellend M, Inouye BD, Freestone AL, Sanders NJ, Cornell HV, Comita LS, Davies KF, Harrison SP, Kraft NJ, Stegen JC, Swenson NG (2011) Navigating the multiple meanings of β diversity: a roadmap for the practicing ecologist. Ecology Letters 14(1): 19–28. https://doi.org/10.1111/j.1461-0248.2010.01552.x
Andreenkov OV, Andreenkova NG, Zhimulev IF, Tsybulin SM (2020) Nesting of the Black-headed Gull and other gulls on the islands of the Novosibirsk Reservoir. Fauna of the Urals and Siberia 2:16-22 [In Russian].
Andriushchenko YuA, Siokhin VD, Chernichko II, Chernichko RN, Matsyura AV (2000) Central Sivash: abundance and distribution of nesting waterbirds in the wetlands of the Azov-Black Sea coast of Ukraine. In: Abundance and Distribution of Nesting Waterbirds in the Wetlands of the Azov-Black Sea Coast of Ukraine. Melitopol; Kyiv. P. 217-250 [in Russian].
Barbazyuk EV (2020) On the ecology of the Great Black-headed Gull, Gull-billed Tern and Caspian Tern in the Orenburg region. Steppe Science 1(XVI): 37-51. https://doi.org/10.24411/9999-006А-2020-10005 [in Russian].
Fink DT, Auer AJ, Strimas-Mackey M, Ligocki S, Robinson O et al. (2023) eBird Status and Trends. Data Version: 2022. Cornell Lab of Ornithology, Ithaca, New York. https://doi.org/10.2173/ebirdst.2022
Hubbell SP (2001). The unified neutral theory of biodiversity and biogeography. Princeton: Princeton University Press, 375 pp.
Kadmon R, Allouche O (2007) Integrating the effects of area, isolation, and habitat heterogeneity on species diversity: a unification of island biogeography and niche theory. Am Nat. 170(3):443-454. https://doi.org/10.1086/519853
Kharitonov S (1999) Breeding-site fidelity and colony formation in the great black-headed gull. Branta 2:64-75.
Laurance WF (2008) Theory meets reality: How habitat fragmentation research has transcended island biogeographic theory. Biological Conservation 141(7): 1731–1744. https://doi.org/10.1016/j.biocon.2008.05.011
Ławicki Ł (2012). Great Black-headed Gull: why is it still so rare in northern and western Europe? Birding World 25:380-389.
MacArthur RH, Wilson EO (2001). The theory of island biogeography. Princeton, N.J: Princeton University Press, 203 pp. https://doi.org/10.1515/9781400881376
Matsyura A (2000) Interactions between the Yellow-legged gull (Larus cachinnans), the Great black-headed gull (Larus ichthyaetus), and the Great cormorant (Phalacrocorax carbo) breeding on Kitay Island (Central Sivash). Vestnik Zoologii 14(2):76-79 [n Russian].
Matsyura AV, Siokhin VD (2025). Spatial patterns of breeding colonies of Great Cormorant (Phalacrocorax carbo) and Palas’s Gull (Larus ichthyaetus) on Kitay Island in the Central Sivash lagoon system. Acta Biologica Sibirica 11:1137-1151. https://doi.org/10.5281/zenodo.17432470
Mierauskas P, Buzun V (1991) Competitive interactions between the Herring Gull L. a. cachinnans and the Great Black-Headed Gull L. ichthyaetus at Sivash Lake (South Ukraine). Seevögel-Zeitschrift des Vereins Jordsand zum Schutz der Seevögel und der Nature 12(2):33-35
Panov EN (2009) The social and communication behaviour of the Great Black-headed Gull. British Birds 102: 72-83
Sax DF, Gaines SD (2008) Species invasions and extinction: the future of native biodiversity on islands. Proc Natl Acad Sci USA. 105(suppl 1):11490-11497. https://doi.org/10.1073/pnas.0802290105
Siokhin VD (2000) Characteristics of the distribution and abundance of nesting birds in the wetlands of the Azov-Black Sea coast. Branta 3:412-444 [in Russian].
Siokhin VD, Chernichko II, Adamatskaia TB et al (1988) Colonial Hydrophilic Birds of the South of Ukraine: Charadriiformes. K.: Naukova Dumka, 174 pp. [in Russian].
Siokhin VD, Gorlov PI, Kostiushyn VA (2021) Long-term population dynamics of birds on the islands of Sivash and Dzharylgach Bay during the nesting period. Collection of Scientific Works Dedicated to the 35th Anniversary of the Interdepartmental Azov-Black Sea Ornithological Station. Melitopol; 160-165 [in Russian].
Siokhin VD, Matsyura AV (2025) Current state of colonial birds in the island complexes of the Sivash region. Russian Ornithological Journal 34(2520): 1678-1683 [in Russian].
Somers Ch, Doucette J, Weseloh D, Kjoss V (2011). Interactions between Double-crested Cormorants and other ground-nesting species. Waterbirds 34:168-176. https://doi.org/10.1675/063.034.0205
Stephens SC, Koons DN, Rotella JJ, Willey DW (2004) Effects of habitat fragmentation on avian nesting success: a review of the evidence at multiple spatial scales. Biological Conservation 115(1):101-110. https://doi.org/10.1016/S0006-3207(03)00098-3
Whittaker RJ, Fernández-Palacios JM, Matthews TJ (2008) Island Biogeography: Ecology, Evolution, and Conservation. 2nd ed. Oxford University Press, 416 pp.
This work is licensed under a Creative Commons Attribution 4.0 International License.