Biology subjects

da Silva, C. R. B.

Publications and source records attributed to da Silva, C. R. B..

3 recordsLinked to original sources

bioRxiv2023

Local climate change velocities explain multidirectional range shifts in a North American butterfly assemblage

Species are often expected to shift their distributions poleward to evade warming climates. However, from 18 years of fixed transect monitoring data on 88 species of butterfly in the midwestern United States, we show that butterflies are shifting their centroids in all directions, except towards the region that is warming the fastest (southeast). Butterflies shifted their centroids at a mean rate of 4.87 km yr-1. The rate of centroid shift was significantly associated with local climate change velocity (temperature and precipitation), but not with mean climate change velocity throughout the species ranges. Surprisingly, the centroid shift was also unrelated to species traits expected to mediate the shift response including thermal niche breadth (range of climates butterflies experience throughout their distribution) and wingspan (often used as metric for dispersal capability). Contrasting with a number of previous studies, we observed relatively high phylogenetic signal in the rate and direction species shifted their centroids, suggesting that evolutionary history helps to explain multidirectional range shift responses and that some groups of species will be better able to shift their ranges than others. This research shows important signatures of multidirectional range shifts (latitudinal and longitudinal) and uniquely shows that local climate change velocities are more important in driving range shifts than the mean climate change velocity throughout a species entire range.

ecology↗

bioRxiv2022

Physiological traits and their relationships vary along an aridity gradient within and among Fijian bee species

O_LITemperature and water availability are hypothesised to be important abiotic drivers of the evolution of metabolic rates and gas exchange patterns, respectively. Specifically, the metabolic cold adaptation hypothesis (MCA) predicts that cold environments select for faster metabolic rates to counter the thermodynamics of biochemical reactions while the hygric hypothesis predicts that dry environments select for discontinuous gas exchange to reduce water loss. C_LIO_LIAlthough these two hypotheses consider different physiological traits and how they vary along different abiotic gradients, metabolic rate drives frequency of gas exchange patterns in insects meaning these two traits are inherently linked. Despite this link, the MCA and hygric hypotheses are rarely considered together and the extent to which metabolic rates and frequency of gas exchange vary and co-vary across climatic gradients remains unclear. C_LIO_LIWe tested the MCA and hygric hypotheses within a species of endemic Fijian bee, Homalictus fijiensis, across an altitudinal gradient of 1100 m, and among four Fijian bee species, including H. fijiensis, that inhabit different altitudinal bands. In Fiji, environmental temperature is [~]5{degrees}C lower in the central highlands than in the coastal lowlands with the highlands receiving [~]100 mm of additional precipitation than the lowlands each month. C_LIO_LIWe found an MCA-like pattern within H. fijiensis and among Fijian bee species, where metabolic rate decreased with increasing temperature, but precipitation also explained variation in metabolic rate. However, we did not find support for the hygric hypothesis within H. fijiensis or among species (frequency of gas exchange was not negatively correlated with precipitation). C_LIO_LIThe relationship between metabolic rate and frequency of gas exchange was steeper for species that occupied lower elevations on average, suggesting it is possible that these two traits can evolve independently of each other despite being positively correlated. C_LI

evolutionary biology↗

bioRxiv2022

Linking physiology to ecosystem function: how vulnerable are different functional groups to climate change?

O_LIThe resilience of ecosystem function under global climate change is governed by individual species vulnerabilities and the functional groups they contribute to (e.g. decomposition, primary production, pollination, primary, secondary and tertiary consumption). Yet it remains unclear whether species that contribute to different functional groups, which underpin ecosystem function, differ in their vulnerability to climate change. C_LIO_LIIt is important to examine if functional group vulnerability differs across space (e.g. tropical vs temperate latitudes) to determine if some regions will be more vulnerable to loss of ecosystem function than others, and to examine whether localized effects of particular community compositions override global patterns of functional group vulnerability. C_LIO_LIWe used existing upper thermal limit data across a range of terrestrial species (N = 1,743) to calculate species warming margins (degrees distance between a species upper thermal limit and the maximum environmental temperature they inhabit), as a metric of climate change vulnerability, to determine whether species that comprise different functional groups exhibit differential vulnerability to climate change, and if vulnerability trends change across geographic space. C_LIO_LIWe found that primary producers had the broadest warming margins across the globe ( = 21.85 {degrees}C) and that tertiary consumers had the narrowest warming margins ( = 4.37 {degrees}C), where vulnerability tended to increase with trophic level. C_LIO_LISpecies that contribute towards primary production were more vulnerable in low-latitude than mid-latitude regions, but warming margins across all other functional groups did not differ across regions when evolutionary history was considered. However, when evolutionary history was excluded from the analyses (as closely related species often play similar functional roles within ecosystems demonstrating true variation in functional group warming margins) we found that pollinators are more vulnerable in mid-latitude regions and that primary producers are more vulnerable in low-latitude environments. C_LIO_LIThis study provides a critical first step in linking individual species vulnerabilities with whole ecosystem responses to climate change. C_LI

ecology↗