Biology subjects

Kati, V.

Publications and source records attributed to Kati, V..

4 recordsLinked to original sources

bioRxiv2026

Distinct but interacting functional filters of aridity and grazing shape Mediterranean mountain grasslands

Mediterranean mountain grasslands are ecosystems of high ecological and economic value. They are shaped by the dry and warm climate and land use, such as grazing, although the combined effects of both drivers remain poorly understood. In this study, we analyzed shifts in functional composition in thirty-two plant communities in Mediterranean mountain grasslands of the Pindos Range (Greece) by measuring five plant functional traits related to resource acquisition in dominant plant species. We examined the adaptive value of each trait as well as community-level responses along a well-defined two-dimensional gradient of grazing intensity and aridity, using mixed models and functional diversity analyses, and tested whether individual species trait shifts are related to aridity and grazing intensity. At the community level, aridity decreased plant height and leaf area whereas grazing only affected traits associated with tissue recovery such as high specific leaf area (SLA) and low community-weighted mean leaf dry matter content (LDMC). As aridity increased, plant height functional dispersion decreased. This convergence pattern indicates a shift towards more similar growth forms under arid conditions. Species-specific analysis indicated various responses of traits to the interaction of aridity and grazing that could not be detected using only community-level patterns. Overall, our findings demonstrate that aridity and grazing act through separate functional axes at the community level, while their combined effects emerge through species-specific trait plasticity.

ecology↗

bioRxiv2025

Butterflies Are Shrinking: Evidence from the Past Century

Climate change has had strong impacts on biodiversity, including well-documented shifts in the distributions and phenology of species. Reductions in body size represent a third pervasive biological response; it has garnered significantly less attention despite great ecological relevance. Theoretical frameworks-the temperature-size rule, Bergmanns rule, and Jamess rule-predict that warmer temperatures are associated with smaller body sizes in ectotherms. In contrast, empirical evidence concerning this pattern is mixed across both taxa and environments. In the present study, we applied computer vision techniques to historical data from two large butterfly museum collections, totaling 593 species across 10 terrestrial biomes over more than a century, in order to investigate long-term trends in butterfly body size. We measured forewing length through both manual image analyses and automated computer vision algorithms proxying body size and analyzed trends by using generalized additive models in order to consider a temporal, biome-specific pattern assessment. We have tested two hypotheses: that butterfly body size (1) declines over time, in conjunction with increasing ambient temperatures, in agreement with the temperature-size rule, and (2) its variation is more marked in warm, dry biomes. Results indicate a significant overall reduction in the body size of butterflies during the last century and that this reduction is indeed more pronounced in those biomes facing higher rises in temperature. These findings constitute large-scale evidence in support of the temperature-size rule and indicate a potential ecological impact of climate change on butterfly populations.

ecology↗

bioRxiv2025

Butterfly body size shrinkage: the impact of ecological traits across varied environments

Because of its close ties to numerous ecological and life history characteristics, body size is regarded as one of an organisms most important characteristics and is frequently considered a significant indicator of fitness. According to recent studies, ectotherms in particular, may see a reduction in body size with rising temperatures. How life history and ecological traits influence, however, shifts in butterfly body size in response to environmental changes, particularly focusing on the effects of temperature and land use is poorly studied. Using Generalized Additive Models (GAM), we analyzed forewing length data alongside various life history (phenology, overwintering developmental stage, voltinism, diet breadth, gender) and ecological traits (mobility, thermal tolerance) as well as environmental parameters for a period that lasts 110 years. Smaller body sizes were linked to early-season emergence and increasing forest cover, while larger sizes were linked to longer flight durations and later seasonal appearance. Males exhibited a pronounced decline in body size while females showed an opposite trend, suggesting sex-specific vulnerabilities to climate change. This research highlights the complex interplay between climate change, habitat fragmentation, and butterfly morphology, emphasizing the need for further investigation into sexual size dimorphism as anthropogenic influences continue to reshape butterfly populations.

ecology↗

bioRxiv2025

Climate-Driven Reshuffling of Butterfly Communities: Body Size Declines and Community Homogenization in a Rapidly Warming Switzerland

Climate change has been reshaping natural communities by driving species to change their ranges in response to warming temperatures. In Switzerland, the rate of warming since 1950 has approached nearly double the global average, making these impacts important for community composition and ecosystem function. Using the Community Weighted Length Index (CWLI) as the body size estimator, previously extracted by museum specimens, we studied two decades of butterfly community data that have been inventoried by the Biodiversity Monitoring Switzerland program. We checked for deviations from the expectation of random trends in the CWLI using null models. We modeled the long-term patterns at each site and the overall long-term patterns through linear regression and mixed-effects models alongside the model of the relationship between wing length, elevation, and abundance. CWLI of Swiss butterfly assemblages dropped by 5.2% over two decades, suggesting that warmer temperatures are differentially affecting large-bodied species. While CWLI trends were significantly declining at most sites (73%), a subset of sites (27%) showed trends of increasing CWLI, sometimes associated with cooler microclimates either in forests or at higher elevation. Our results further indicate a progressive homogenization of butterfly communities, marked by smoother CWLI slopes and reduced CWLI range over time. These results underline complex relations of climate-driven range shifts with body-size dynamics and community restructuring, emphasizing the importance of understanding the processes to mitigate biodiversity loss in thermally sensitive ecosystems.

ecology↗