Obscure 2 emu4/9/2023 ![]() ![]() Blue tones represent areas that more densely occupied in the more recent past (Time 1) and have thus increased over time.Ĭhanges in avian functional diversity across the Earth's major zoogeographic realms. Brown tones represent areas of the functional trait space that are more densely occupied in the distant past (Time 3) and have thus decreased over time. (C) Overall changes in functional diversity over time (expressed in quantiles), measured as differences in TPDs between Time 1 and Time 3. The observed value of dissimilarity between Time 3 and Time 1 is demarcated by the red "X" along the x-axis. (B) Distribution of overall dissimilarity indices between TPDs from Time 3 and Time 1, based on randomly generated abundances for each species in each time period (n = 1000 iterations). Brown arrows in Rightmost panel depict peripheral regions of functional space which have eroded over the past million years (see Results). Contour lines and color gradients represent density of species in the defined space, where 50% (0.5) of all species analyzed fall with the "hotspot" depicted by the first contour (red) and subsequent lines indicate the 0.6, 0.7, 0.8, 0.9, and 0.99 quantiles. (A) Trait probability densities (TPDs), calculated via abundance-weighted PCA of six key morphological/life-history traits (arrows illustrate direction and weighting of each trait along PC1 and PC2), depicting probabilistic distributions of species in functional trait space. The integration of paleodemographic dynamics with functional trait data enhances our ability to quantify losses of biosphere integrity before anthropogenic disturbances and attribute contemporary biodiversity loss to different drivers over time.Ĭhanges in occupation of the functional trait space of 263 bird species across three time periods over the last one million years. Overall, our results identify fluctuations in functional space of extant species over evolutionary timescales and represent the demographic-based vulnerability of different regions of functional space among these taxa. ![]() Further, species most sensitive to climate warming occupied a relatively narrow region of functional space, indicating that the largest potential population increases and decreases under climate change will occur among species with relatively similar trait sets. ![]() Our results suggest that patterns of population decline over the Pleistocene have been concentrated in particular regions of trait space associated with extreme reproductive strategies and low dispersal ability, consistent with an overall erosion of functional diversity. We show that functional diversity was relatively stable over this period, but underwent significant changes in some key areas of trait space due to changing species abundances. We combine morphological, ecological, and life-history trait data for >260 extant bird species with genomic-based estimates of changing effective population size (Ne) to quantify demographic-based shifts in avian functional diversity over the past million years and under pre-anthropogenic climate warming. Despite evidence of declining biosphere integrity, we currently lack understanding of how the functional diversity associated with changes in abundance among ecological communities has varied over time and before widespread human disturbances. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |