Research in Ecology

Impacts and status of Invasion by Lantana camara in natural forests of an Indo-Burma biodiversity hotspot region- A case study in Mizoram, India

Rabishankar Sengupta — 2024-06-18

Invasion by Lantana camara represent a major threat for biodiversity and ecosystems functioning on a global scale. In this study, we investigated the ecological impact of Lantana camara invasion in natural forests of Mizoram. The sampling plots were implemented within six sites spread across the state and Lantana camara invasion were investigated along altitudinal gradient. In addition to the associated floristic inventory, we gathered the socio-economic utilization data. The results revealed that Lantana camara invasion cause adverse effects where it may result into suppression of various native plant species of invaded communities. The floristic and phytosociological assessment from Lantana camara invaded natural forests revealed a total of 74 species belonging to 68 genera and 30 families. Herbs were the dominant habit (60%) followed by shrubs (26.67%) and climbers (13.33%). The most dominant family was represented by Asteraceae with 18 species belonging to 16 genera. The general plant species diversity, density, richness and importance value index were reduced by the invasion of Lantana camara. Hence, based on the associated species present in the invaded study areas, forest management activities may be followed for the sustainable control measures to eliminate the spread of the invasive Lantana camara. This study recommends the imperative nature of effective Lantana camara management, particularly during the initial stages of invasion.

Allelopathic impact of Chromolaena odorata on the local crops in Mizoram, India

Rabishankar Sengupta — 2024-06-26

Allelopathy is the major biological advantage of an invasive alien plant, often inhibitory to the germination and growth of other plants within their space. This study aimed to demonstrate the allelopathic effect of Chromolaena odorata extracts on seed germination and seedling growth of four commonly grown crops as test plants in Mizoram. Chromolaena odorata was observed as one of the dominant invasive alien plants in the natural forests of Mizoram with increased abundance and lower diversity in the invaded areas during frequent field visits. Petri plate and pot bioassay study revealed that the increasing concentrations (control, 2.5, 5, 7.5, 10 and 15%) of aqueous extracts or leachates inhibited seed germination, root and shoot length, vigour index. Bioassay treatment of the test plants with a higher concentration of C. odorata extract exhibited a significant inhibition of germination and test plant growth. Preliminary phytochemical analysis exhibited the presence of Alkaloids, Tannins, Saponins, Terpenoids and Flavonoids. The inhibitory effects on seed germination confirmed the inhibitory allelopathic potential of Chromolaena odorata in cultivated lands of Mizoram which may be attributed to presence of the allelochemicals in the leaf and stem extracts of the IAPs.

Pallas’s Gull Ichthyaetus ichthyaetus and Fish Farming of the Palearctic: Review

Sergey Golubev — 2024-07-15

The Pallas’s Gull Ichthyaetus ichthyaetus is a piscivorous predator and scavenger, some breeding populations of which are vulnerable and require protection. This study analyzes the status and distribution of Pallas’s Gull in Palearctic fish ponds—man–made bodies of water where fish concentrations are controlled by humans and can be many times higher than natural values. The aim of the study was to assess the state of the Pallas’s Gull in the fish farming of the Palearctic over the last ≈ 60 years. The review was based on > 1100 publications found in the search engines Yandex, Google, Google Scholar, eLybrary. Between the 1960s and 2020s, the Pallas’s Gull was discovered in 46 fish farms in the Palearctic. Breeding has been established in 3 fish farms, breeding has not been established in 38 fish farms, and birds were present in 5 fish farms, but the status was not specified. There were 35 places of contact with fish farms in Europe, and 11 places of contact in Asia. The average area of fish farms with which Pallas’s Gull came into contact was 10.7 km² (n = 21). Fish farms support non–breeding individuals –– vagrants, visitors, summer or winter residents of different age classes. Fish farms cannot be considered as important places for the reproduction of the species. The network of fish farms plays a certain auxiliary, but far from decisive role in maintaining the population and the current multidirectional expansion of the species’ range in the Palearctic. The hypothesis about the possible important role of reservoirs and fish farms in food supply and the distribution of Pallas’s Gull beyond the historical range was not confirmed in studies of fish farms.