Common Names: Sri lanka whistling-thrush, Ceylon Whistling-Thrush, Ceylon Whistling Thrush, Ceylonpfeifdrossel
1. Endemicity and land-use type influence the abundance-range-size relationship of birds on a tropical island.
Sreekar R, Sam K, Dayananda SK, Goodale UM, Kotagama SW, Goodale E
The Journal of animal ecologyJ Anim EcolEndemicity and land-use type influence the abundance-range-size relationship of birds on a tropical island.460-47010.1111/1365-2656.13379A single adverse environment event can threaten the survival of small-ranged species while random fluctuations in population size increase the extinction risk of less-abundant species. The abundance-range-size relationship (ARR) is usually positive, which means that smaller-ranged species are often of low abundance and might face both problems simultaneously. The ARR has been reported to be negative on tropical islands, perhaps allowing endemic species in such environments to remain extant. But there is a need to understand how endemism and land-use interact to shape ARR. Using 41 highly replicated transects along the full elevational gradient of Sri Lanka, we determined the following: (a) the direction of ARR, (b) if endemism affects ARR and (c) if land-use (rainforest, buffer and agriculture) changes ARR differently for endemics and non-endemics. Additionally, (d) we identified endemics that had both lower abundances and smaller range sizes, and ranked them from most threatened (specific to rainforests) to least threatened using a weighted-interaction nestedness estimator. (a) We found a positive relationship between species abundances and range size. This positive ARR was maintained among endemic and non-endemic species, across land-use types and at local and regional scales. (b) The ARR interacted with endemicity and land-use. Endemics with smaller range sizes had higher abundances than non-endemics, and particularly higher in rainforests compared to agriculture. In contrast, species with larger range sizes had similar abundances across endemicity and land-use categories. Many endemics with smaller range sizes are globally threatened; therefore, higher abundances may buffer them from extinction risks. (c) Nine (29%) endemics had both below average abundance and elevational range size. The nestedness estimator ranked the endemics Sri Lanka Whistling Thrush Myophonus blighi, Red-faced Malkoha Phaenicophaeus pyrrhocephalus, Sri Lanka Thrush Zoothera imbricata and White-faced Starling Sturnornis albofrontus as the four most vulnerable species to local extinction risk, which corresponds to their global extinction risk. We demonstrate that ARR can be positive on tropical islands, but it is influenced by endemism and land-use. Examining shifts in ARR is not only important to understand community dynamics but can also act as a tool to inform managers about species that require monitoring programmes.© 2020 British Ecological Society.SreekarRachakondaR0000-0001-5445-6589Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic.Department of Biological Sciences, National University of Singapore, Singapore, Singapore.SamKaterinaK0000-0002-3436-0579Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic.Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.DayanandaSalindra KSKGuangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China.Field Ornithology Group of Sri Lanka, Department of Zoology, University of Colombo, Colombo, Sri Lanka.GoodaleUromi ManageUM0000-0003-3111-8899Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China.KotagamaSarath WSWField Ornithology Group of Sri Lanka, Department of Zoology, University of Colombo, Colombo, Sri Lanka.GoodaleEbenE0000-0003-3403-2847Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China.engJournal ArticleResearch Support, Non-U.S. Gov't20201105EnglandJ Anim Ecol03765740021-8790IMAnimalsBiodiversityBirdsEcosystemIslandsPopulation DensityRainforestabundance-range-size relationshipagricultureextinction riskisland endemicsland-use20200602202010162020102160202142060202010201710ppublish3308004810.1111/1365-2656.13379REFERENCES, 2021