Väitös (biologia): MSc Prakhar Rawal

MSc Prakhar Rawal esittää väitöskirjansa ”From a megacity to boreal forests: Making the most of wetlands for waterbirds – Drivers shaping bird communities and their breeding success in wetland of different landscapes” julkisesti tarkastettavaksi Turun yliopistossa perjantaina 11.9.2026 klo 12.00 (Turun yliopisto, Agora, XXII-luentosali, Vesilinnantie 3, Turku).

Vastaväittäjänä toimii dosentti Elie Gaget (Research institute for the conservation of Mediterranean wetlands, Ranska) ja kustoksena professori Toni Laaksonen (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on biologia.

Tiivistelmä väitöstutkimuksesta:

Wetlands are important habitats for biodiversity, including a group of birds that require them for feeding, breeding, and roosting. Since 1700, around one-fifth of wetlands are estimated to have been lost globally, resulting in declining populations for a large number of wetland birds. Restoring degraded wetlands and creating new ones has been used a strategy to oppose wetland losses. These efforts require huge amount of different resources – money, time, and effort. Identifying the wetlands that birds select for breeding, and why, is important feedback to manage wetlands better in present and build better habitats in future. Further, a significant fraction of European wetland bird species are migratory, breeding in Europe and wintering in Africa and Asia. Therefore, improving habitats in wintering grounds is as important as breeding habitats.

In this thesis, I study wetland bird communities in two extremely contrasting landscapes – densely populated megacity of Delhi (India) and boreal forested and rural landscapes of Finland. In Delhi, I focused on ponds (wetlands < 5 ha) distributed throughout dense urban core to rural outskirts. Meanwhile in Finland I studied restored and newly constructed wetlands distributed throughout the country. These were constructed and restored under various projects, including the SOTKA project launched by Ministry of Agriculture and Forestry in 2020. In both places I set out with the same objective – understand what wetland features and landscape characteristics make them more attractive for birds.

Delhi's ponds not only recorded a disproportionately high species diversity (37% of Delhi's bird species) relative to their land cover area (< 0.5% of Delhi's area), but also functioned as breeding habitats. Both regions identify some critical variables that drive bird metrics — wetland size, presence or number of islands, urban cover, and vegetation structure. In Finnish wetlands, I also studied the effects of wetland succession (or ageing) and identified peaks in bird abundances at ages 4 and 7, after which they gradually decline.

This thesis adds to the growing evidence of the value of ponds as reservoirs of biodiversity, even within a dense mega-city, suggesting that existing assumptions regarding small urban waterbodies should be revisited. My results underscore the importance of multi-scale planning alongside thoughtful design and adaptive management when creating new wetlands, to ensure long-term conservation benefits. Compiling information on biodiversity patterns across different regions and wetland types provides essential guidance for optimizing biodiversity outcomes of these ecosystems.