The researchers at the Institute of Aquatic Ecology of the ELKH Centre for Ecological Research (CER), led by senior research fellow Emil Boros, conducted a large-scale study on the interaction between alkaline soda pans and waterbirds. According to the results, the occurrence of bird groups shows a close correlation with the attributes of the saline aquatic ecosystems, of which water cover and salinity are the main attributes predicting the type of bird group that occurs in a given environment. The classification system and methodology described in their study can be used to estimate certain environmental attributes of inland water bodies for large geographic regions by counting waterbird populations. The publication presenting the results was published in the prestigious scientific journal Science of The Total Environment.
Relict Gull (Kazakhstan)
The alkaline soda pans of Hungary are special representatives of inland saline waters in the interior of the continents. The largest number of soda pans in Eurasia is found in the Carpathian Basin, and these lakes are also important resting and feeding areas for migratory birds in the Eurasian-African bird migration routes. Evidence is mounting that aquatic habitats and waterbird populations are being rapidly declined globally by the land-use and land cover changes of recent decades (drainage, run-off), and climate change: rising temperatures and changing rainfall patterns. Waterbird populations play a crucial role in trophic- and host-parasite networks, and their cultural and recreational role is also important, but as bird populations and habitats decline, these ecological services are also declining.
White pelican (Kazakhstan)
Emil Boros, senior research fellow at the Institute of Aquatic Ecology of CER, has been studying the interaction between waterbird populations and soda pans for many years. In an earlier publication in the Science of the Total Environment they found that waterbirds contribute high phosphorus loading (P) to the shallow saline lakes through their droppings, i.e. birds act as vectors of external phosphorus sources, a process called guanotrophication (bird-induced nutrient enrichment). Waterbirds, such as large-bodied herbivores (goose and duck species) and medium-bodied omnivores (e.g. gulls) have been shown to be 64% responsible for the extremely high phosphorus content of natural soda pans. However, it was also found that the hypertrophic state of water was in contradiction with the limited primary production of natural soda pans due to the characteristics of the lakes: shallow water depth, high alkalinity (PH ≥ 9), and intermittent hydrological cycle.
Shalkarteniz saline lake (Kazakhstan)
In a further investigation about the interaction between inland saline aquatic ecosystems and waterbirds, the aim was to show whether the ecological/trophic attributes of saline water bodies could be predicted on multi-spatial scales by different groups (guilds) of waterbirds. Also published in the prestigious journal Science of the Total Environment, Emil Boros and colleagues studied a vast area along a more than 1,000 km South-East line on different spatial scales in the steppe and semi-desert region of Kazakhstan, where 63 sample areas were selected. Nearly 100 waterbird species occurred in the sample areas and were classified into three groups according to their role in nutrient cycling and nutrient turnover: net-importers (large herbivores, e.g., geese, cranes), importer-exporters (omnivorous ducks and gulls) and net-exporters (various herbi-, omni- and piscivorous species), based on Boros’s classification method. The abundance, biomass and diversity of these bird groups (guilds) were compared with the ecological attributes of the inland waters on multi-spatial scales, e.g. water depth, chlorophyll content, and at larger spatial scales, with the area of land cover data found in the 1 and 10 km radius around the ponds, e.g. grassland or agricultural land.
Zab-szék (Hungary)
Their results showed that the occurrence of the above waterbird groups was strongly correlated with the ecological attributes of the saline aquatic ecosystems on a multi-spatial scale. Water cover and salinity are the main attributes predicting the type of bird group that occurs in a given environment. The importer-exporter and net exporter bird groups showed positive correlations with productivity metrics and water depth of the waters, while the importers were predicted by the surrounding pond environment, e.g. grassland.
The practical significance of this study is that it quantifies the ecosystem services provided by waterbirds, their role in nutrient cycling, which is essential for effective monitoring and habitat management. The classification system and methodology described in this study can be used to estimate certain environmental attributes of inland water bodies for large geographic regions by counting waterbird populations. In the future, this will provide an opportunity to use birds to estimate ecosystem function and services of aquatic systems, which in turn will require further methodological studies for different geographical regions.
Publications:
Emil Boros, Zarina Inelova, Zsuzsanna Lánczos, Zsolt Végvári (2023). Waterbird guilds predict environmental attributes of inland saline aquatic ecosystems on multi-spatial scales. Science of The Total Environment, Volume 855. DOI: 10.1016/j.scitotenv.2022.158845.
Emil Boros, Anita Takács, Péter Dobosy, Lajos Vörös (2021). Extreme guanotrophication by phosphorus in contradiction with the productivity of alkaline soda pan ecosystems. Science of The Total Environment, Volume 793. DOI: 10.1016/j.scitotenv.2021.148300
Photos by Emil Boros