| Title |
Impact of environmental factors on the structure of fish communities, isotopic ratio in hydrobionts and trophic levels in the rivers ecosystem of different ecological state / |
| Translation of Title |
Aplinkos veiksnių įtaka žuvų bendrijų struktūrai, hidrobiontų izotopiniam santykiui ir mitybos lygmenims skirtingos ekologinės būklės upių ekosistemose. |
| Authors |
Čivas, Laurynas |
| Full Text |
|
| Pages |
29 |
| Keywords [eng] |
River ecosystems ; ecological state ; hydrobionts ; trophic levels, organic mater ratio |
| Abstract [eng] |
River ecosystems are significant reservoirs of biodiversity and constitute the principal source of renewable water supply for humans and freshwater ecosystems. However, nowadays rivers are under unprecedented anthropogenic stress worldwide and, according to the Millennium Ecosystem Assessment, may be among the most endangered ecosystems on the planet. The aim of this thesis is to investigate the influence of abiotic factors on fish communities structure and isotopic ratio in hydrobionts in Lithuanian rivers of different ecological state. Fish community structure in the rivers studied was found to depend on ecological conditions therein. The ecological state of the Žeimena River was assessed as good or very good, whereas that of the Nevėžis River as moderate. Trophic levels and the proportion of organic matter in hydrobionts diet were found to be statistically significantly dependent on their function in the food web. The results obtained show that trophic levels of hydrobionts, the proportion of organic matter in their diet and parameters of river food webs depend on the river stretch morphology and the cumulative effect of environmental factors determining the general ecological state of rivers. The data obtained are significant for environment protection, the study of climate change impact on riverine fish communities, sustainable development, protection of biodiversity, primary ecosystems and ecological processes in the Baltic region. |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Summaries of doctoral thesis |
| Language |
Lithuanian |
| Publication date |
2017 |
