Girish, K. S. | Search bioRxiv

bioRxiv2026

ClimLimits: a global database of multivariate realized climate limits for animal species

Introduction and AimAssessing the realized climate limits for a species based on the climate conditions (i.e., different aspects of temperature and precipitation) a species has experienced over its range enables us to determine the climatic boundaries of its existence, and thus its potential exposure to novel climate conditions in the future. We combine species range maps from IUCN and BirdLife International with global climate data from the ERA5 reanalysis and five Earth System Models (ESMs) to produce ClimLimits: a database of multivariate realized species climate limits based on historical temperature and precipitation for terrestrial and freshwater animal species worldwide. Main variables includedFor a total of 54,255 species (24,731 terrestrial, 18,182 freshwater, and 11,342 terrestrial-freshwater species), we estimated 44 species climate limits, which delineate the most extreme climate conditions experienced by a species over its entire range over the last 80 years (1940-2020). The database accounts for three aspects of species climate limits: a) maximum and minimum values of temperature and precipitation experienced over the historical reference period, b) maximum annual variability in temperature and precipitation, and c) maximum frequency, intensity, duration and severity of extreme events (heatwaves, cold-spells, and droughts). Climate data is sourced from the ERA5 reanalysis and from five different Earth System Models (ESMs), producing 6 different subsets of the ClimLimits database. Time coverageSpecies climate limits are estimated based on historical climate records from 1941-2014 (5 ESMs) and 1940-2020 (ERA5). Temperature-based limits are inferred at a daily scale, while precipitation-based limits are inferred at a monthly and yearly scale. Spatial coverageGlobal, over 24km x 24km grid-cells. TaxaTerrestrial and freshwater taxa, including amphibians, birds, mammals, reptiles, freshwater fish, and freshwater invertebrates, with shapefiles from IUCN and BirdLife International. Data is produced at the species level. ApplicationsClimLimits provides ready-to-use standardized realized climate limits for individual species across multiple aspects of climate, facilitating global-scale assessments of macroecological patterns and climate exposure risk for species.

ecology↗

bioRxiv2020

Preliminary evidence for upward elevational range shifts by Eastern Himalayan birds

The ongoing climate crisis is one of the most significant threats to biodiversity globally. As the Earth warms, species have adapted by shifting their geographical ranges either polewards, or in mountainous regions, upslope towards higher elevations, presumably to continue to inhabit a suitable thermal environment. Upslope range shifts are of particular concern in tropical mountain ranges because: (a) tropical species are particularly thermally sensitive, (b) as species move upwards, they can run out of habitable space, leading to local extirpations, and (c) tropical mountains harbour a disproportionately high fraction of the planets terrestrial biodiversity - rapid upslope range shifts can therefore result in significant biodiversity losses. We used citizen science data over a 13-year period to evaluate whether 39 eastern Himalayan bird species might be shifting to higher elevations over time, by analyzing changes in the frequency of reporting of these species at birdwatching hotspots. For these species, we find evidence consistent with upslope range shifts, with species with the bulk of their elevational ranges below the hotspot elevation showing increases in their reporting frequency over time, and those with most of their elevational ranges above the hotspot elevation declining in reporting frequency. Our findings are suggestive of rapid responses to climate change by eastern Himalayan birds. We caution that eastern Himalayan bird species might be at special risk from increasing global temperatures because of their heightened thermal sensitivity coupled with particularly high rates of warming in the region. Eastern Himalayan birds are likely to require large tracts of undisturbed natural habitat across entire elevational gradients to be able to track changing temperatures by moving to higher elevations to remain resilient to climate change. SUMMARYO_LIOne of the most fundamental responses of species to changing temperatures is to change their geographic ranges, possibly to track the range of temperatures that is ideal for their survival. C_LIO_LIWith increasing climate warming, this shift could happen by moving towards the poles or in mountainous areas, towards the summit. C_LIO_LIDue to the high thermal sensitivity of tropical species and the decrease in space as species move up mountains, the extremely biodiverse bird communities of tropical mountains are particularly vulnerable. C_LIO_LIUsing citizen science data from birding hotspots along an elevational gradient in the Eastern Himalayas over a 13-year period, we measured the change in reporting frequency of 39 common bird species. C_LIO_LIChanges in reporting frequency are generally consistent with the fact that upslope shifts are taking place in the Eastern Himalayas, similar to results for birds from other tropical mountains. C_LI

ecology↗