RT info:eu-repo/semantics/masterThesis
T1 Species richness of hornworts and liverworts on islands: A preliminary analysis of geographic and anthropogenic drivers
A1 Kropp, Rebecca Magdalena
A2 Máster Universitario en Biodiversidad Terrestre y Conservación en Islas
AB Environmental factors related to geography and climate are generally amongthe most significant drivers of species richness across spatial and temporal scales.Among the most studied attributes explaining patterns of species richness onislands are island area and geographic isolation, the two main factors that foundedthe Theory of Island Biogeography by MacArthur and Wilson (1967). Even thoughtheir theory of the equilibrium on islands represents a generally testable andapplicable model, its simplicity disregards taxa specific traits like long distancedispersal capacities and abiotic factors like climate. Furthermore, the impact ofhuman activity which is known to affect biodiversity at different spatial scales, fromglobal to regional, is not included in the model. Bryophytes and especiallyhornworts and liverworts have comparatively broad distribution ranges due to greatlong distance dispersal abilities and are known to respond very sensitively toenvironmental changes which is why pointed as one of the most efficient taxonomicgroups used as bioindicators of climate change. Based on a compilation of floristicdata from a selection of islands distributed worldwide we investigate thesignificance of various environmental attributes for patterns in species richness ofhornworts and liverworts on islands. We include a set of predictor variablesconsisting in geographic (distance to the mainland coast, area, proportion ofsurrounding landmass, latitude, longitude, maximum elevation), climatic (meanannual temperature, mean annual precipitation, climate change velocity and intraannual seasonality quantified by using the minimum annual temperature range andthe minimum coefficient of variation in monthly precipitation) and one sociodemographic variable (human population density) to determine what factors explainbest variation in species richness across the 95 islands studied. Our results indicatethat besides island area and isolation, the traditional geographical variables,elevation, variation in precipitation and climate change velocity are important driversof species richness of hornworts and liverworts on islands. In contrast, humanpopulation density did not seem to explain patterns of species richness. Despitethese results, we conclude that different families of predictors, including pastecological conditions and human activities, may explain patterns in speciesrichness, which cannot be explained by traditional geographic conditions alone.
YR 2021
FD 2021
LK http://riull.ull.es/xmlui/handle/915/22786
UL http://riull.ull.es/xmlui/handle/915/22786
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 19-may-2024