bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2023.01.12.523738

Experimentally induced drought and growing season stage modulate community-level functional traits in a temperate grassland

Fenollosa, E.·Fernandes, P.·Hector, A.·King, H.·Lawson, C.·Jackson, J.·Salguero-Gomez, R.
View original source ↗Export metadata ↓

Abstract

O_LIExtreme precipitation events are expected to become more intense and frequent with climate change. This climatic shift may impact the structure and dynamics of natural communities and the key ecosystem services they provide. Changes in species abundance under these extreme conditions are thought to be driven by functional traits, morpho-physiological characteristics of an organism that impact its fitness. Future environmental conditions may, therefore, favour different functional traits to those in present-day communities. C_LIO_LIHere, we measure functional traits on 586 vascular plants in a temperate grassland where precipitation has been experimentally manipulated for six years. We calculated community-weighted means of five functional traits (plant height, leaf dry matter content, leaf thickness, specific leaf area, and leaf phosphorus concentration) and compared community-weighted means between three levels of precipitation: drought (-50%), irrigated (+50%), and control. Additionally, we contrasted treatments at two different timings along the growing season: mid-season and late-season. C_LIO_LIWe expected altered community-weighted means for traits associated with a conservative use of water that will result from increased summer stress-induced intraspecific variability in the mid-season and from community composition changes in the late-season, after the field is cut, a common management action across most European grasslands. C_LIO_LIIn the drought treatment, we found significantly lower community-weighted mean plant height and leaf dry matter content. However, we only observed these differences after the mid-season cut. We also observed an increase in leaf phosphorus concentration in the drought treatment before the mid-season cut. A combination of changes in community composition and intraspecific variation contributed to these differences, with community composition being more important after the cut. Species with higher height, leaf dry matter content, and lower leaf thickness showed a more pronounced abundance decline at the drought plots. We observed no changes in functional traits community-weighted means in the irrigated treatment compared to those in control and drought treatments. C_LIO_LISynthesis. Our results suggest how the functional trait composition of grassland communities may shift under climate change-induced drought, stressing the interacting effects with growing season stages. C_LI

Explore related subjects

ecologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Fenollosa, E., Fernandes, P., Hector, A., King, H., Lawson, C., Jackson, J., Salguero-Gomez, R.. 2023-01-16. Experimentally induced drought and growing season stage modulate community-level functional traits in a temperate grassland. https://doi.org/10.1101/2023.01.12.523738

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Phenotypic variation in divergent mitochondrial haplotypes in migratory three-spined stickleback

Mitochondria are essential components in life-sustaining organismal processes. The mitochondrial genome can be influenced by selection, and divergent mitochondrial haplotypes have substantial potential to affect interspecies variation in life-history and physiology, yet little is known about whole organism phenotypic changes that might accompany mitochondrial genomic divergence. Three-spined stickleback on the Scottish island of North Uist provide a model to study this as their populations exhibit a well-mixed nuclear genome, yet two highly diverged mitochondrial haplotypes ( trans-Atlantic and European). Three-spined stickleback were sampled from six lochs to investigate associations between mitochondrial haplotype and phenotypic traits including organ size, body size, and ovule volume/clutch size, as well as citrate synthase enzyme activity. Results showed that mitochondrial haplotype has an influence on male gonadosomatic index (GSI) and potentially citrate synthase (CS) enzyme activity. Differences in male GSI may be explained by the timing of male spermatogenesis or potentially a need for larger testes in European haplotype fish. While no other phenotypic trait showed differences between mitochondrial haplotypes, there were many differences between sexes and populations e.g. in body size and organ/muscle size.

ecology↗
bioRxiv2026

Gregariousness can promote invasion success of pest insects while higher environmental heterogeneity decreases it

Climate change and environmental homogenization are expected to facilitate the expansion of many forest pest insect species and increase the vulnerability of forest ecosystems to insect outbreaks. At present, we lack empirical data on how the antipredator defence traits of pest insects interact with the local environmental conditions and shape outbreak risk. Here we study this and ask 1) how the antipredator defence strategy of pest insects shapes survival under naturally varying predator community, and 2) how is predation risk shaped by the diversity and structure of forests? We tested these questions by conducting a field predation experiment with artificial prey system (prey items made from edible dough) where we manipulated the gregariousness, unpalatability and defensive colouration of prey and tested their effects on prey survival. Additionally, we measured environmental variables and invertebrate predator community structure along the prey transects to analyse how they shape overall predation risk. Our results show that the predation risk was always lowest for gregarious prey irrespective of other defence strategies. Furthermore, our results indicate that predation pressure was lower in more homogenously structured forest areas or areas with a weak quality deadwood continuum in comparison to locations with more natural state forests and good quality deadwood continuum. Altogether, our results suggest that gregariousness can facilitate pest insects to form outbreaks by increasing their survival against generalist predators. However, by maintaining higher heterogeneity in forests, it is possible to ensure higher predation pressure to regulate their population growth.

ecology↗
bioRxiv2026

Two decades of EU pesticide substitution have not reduced impacts on stream invertebrates

Chemical regulation assumes that withdrawing hazardous substances and replacing them with alternatives reduces environmental harm. We tested this premise within the EU pesticide regulatory framework using a 23-year record of event-driven pesticide exposure and stream-invertebrate communities from 152 German agricultural streams sampled between 1998 and 2021. Neither pesticide toxic pressure nor pesticide-related invertebrate impairment showed a detectable decline over time, and an improvement equivalent to one ecological status class can be excluded. Dominant toxicity drivers shifted from organophosphates to neonicotinoids and subsequently to pyrethroids, yet the relationship between toxic pressure and community effects remained consistent despite their distinct modes of action. Sustained toxic pressure reflected three mechanisms: successive chemical substitution, prolonged approval periods, and continued exposure to substances no longer authorised as plant protection products. Substitution thus changed which chemicals harm streams, not how much. Measured field outcomes must become the benchmark of pesticide regulation.

ecology↗