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1. Mechanistic understanding of how temperature and its variability shape body size composition in moth assemblages

   https://doi.org/10.1111/1365-2435.14467  

   Chia, Stephanie; Wu, Shipher; Lu, Ya‐Jung; Jang, Yi‐Shin; Huang, Chien‐Chen; Shen, Sheng‐Feng; Chen, I‐Ching; Tuanmu, Mao‐Ning (January 2024, Functional Ecology)

   Abstract Understanding how climate affects trait composition within a biological assemblage is critical for assessing and eventually mitigating climate change impacts on the assemblage and its ecological functioning. While body size is a fundamental trait of animals as it affects many aspects of species' biology and ecology, it remains unclear through what mechanisms temperature and its variability influence within‐assemblage body size variation.This study aims to understand how temperature and its variability shape body size variations in animal assemblages and potentially affect assemblages' vulnerability to climate change. Using >5300 individuals of 680 macromoth species collected from 13 assemblages along a ca. 3000 m elevational gradient in Taiwan, we examined (1) the strength of environmental filtering and niche partitioning in determining the intra‐ and inter‐specific size variations within an assemblage, and (2) the effects of mean temperature and the daily and seasonal temperature variabilities on the strength of the two processes.We found that the body size composition was strongly affected by temperature and its seasonality via both processes. High temperature seasonality enhanced niche partitioning, causing within‐population size convergence. In contrast, low mean temperature and low seasonality both enhanced environmental filtering, causing within‐assemblage size convergence. However, while low temperature restricted the lower size limit within an assemblage, low seasonality restricted both lower and upper size limits.This study indicates an overlooked but important role of temperature seasonality in shaping intra‐ and inter‐specific size variations in moth assemblages through both environmental filtering and niche partitioning. With rising temperatures and amplifying seasonality around the globe, potentially weakened filtering forces may increase the size variation within assemblages, reinforcing the assemblage‐level resilience. Nevertheless, enhanced niche partitioning may limit size variation within populations, which may increase the population‐level vulnerability to environmental changes. This study improves the mechanistic understanding of the climatic effects on trait composition in animal assemblages and provides essential information for biodiversity conservation under climate change. Read the freePlain Language Summaryfor this article on the Journal blog. 

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2. Macroinvertebrate, algal and diatom assemblages respond differently to both drying and wetting transitions in non‐perennial streams

   https://doi.org/10.1111/fwb.14327  

   Busch, Michelle H; Boersma, Kate S; Cook, Stephen C; Jones, C Nathan; Loflen, Chad; Mazor, Raphael D; Stancheva, Rosalina; Price, Adam N; Stubbington, Rachel; Zimmer, Margaret A; et al (November 2024, Freshwater Biology)

   Abstract Biological assemblages in streams are influenced by hydrological dynamics, particularly in non‐perennial systems. Although there has been increasing attention on how drying impacts stream organisms, few studies have investigated how specific characteristics of drying and subsequent wetting transitions influence biotic responses via resistance and resilience traits.Here, we characterized how hydrologic metrics, including those quantifying drying and wetting transitions as well as dry and wet phases, alter diversity and composition of three aquatic assemblages in non‐perennial streams in southern California: benthic macroinvertebrates, soft‐bodied algae and diatoms.We found that flow duration prior to sampling was correlated with variation in macroinvertebrate and soft‐bodied algal assemblage composition. The composition and richness of diatom assemblages, however, were predominantly influenced by the drying start date prior to sampling. Contrary to other studies, the duration of the dry phase prior to sampling did not influence the composition or richness of any assemblage. Although our study was conducted within a region in which each assemblage experienced comparable environmental conditions, we found no single hydrologic metric that influenced all assemblages in the same way.The hot‐summer Mediterranean climate of southern California likely acts as a strong environmental filter, with taxa in this region relying on resistance and resilience adaptations to survive and recolonize non‐perennial streams following wetting. The different responses of algal and diatom assemblages to hydrologic metrics suggest greater resilience to drying and wetting events, particularly for primary producers.As drying and wetting patterns continue to change, understanding biodiversity responses to hydrologic metrics could inform management actions that enhance the ecological resilience of communities in non‐perennial streams. In particular, the creation and enhancement of flow regimes in which natural timing and duration of dry and wet phases sustain refuges that support community persistence in a changing environment. 

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3. Hurricane‐induced changes in mayfly assemblage structure, production and emergence in a tropical island stream

   https://doi.org/10.1111/een.13394  

   Ramírez, Alonso; Meza‐Salazar, Ana M; Gómez, Jesús E; Gutiérrez‐Fonseca, Pablo E; Sánchez‐Ruiz, José (February 2025, Ecological Entomology)

   Abstract Hurricanes are major disturbances with important consequences to stream ecosystems as they create major floods and remove riparian vegetation. Understanding their impacts is a priority, as hurricane intensity is expected to increase due to global climate change.Mayfly assemblages in streams fill a diversity of ecological roles and functions. They are important consumers of algae by scraping benthic biofilms and detritivores associated with fine particles and leaf litter. Other taxa are filterers and even predators. Mayflies are also important prey items in aquatic and terrestrial food webs.Here, we assessed the effects of two consecutive hurricanes that impacted Puerto Rico in 2017 to understand how hurricane‐induced changes in the environment alter mayfly composition, secondary production and emergence.The study was conducted in the Luquillo Experimental Forest, Puerto Rico. Mayflies were sampled as nymphs and emerging adults for 6 months before and 17 months after hurricanes Irma and María hit the island in September 2017. Leaf litter inputs, canopy cover and chlorophyllaconcentrations were monitored along with mayflies.Mayfly assemblages were dominated by two genera of Leptophlebiidae before the hurricane,Neohagenulus (two species: N. julioTraver, 1938,N. luteolusTraver, 1938) andBorinquena (one species: B. carmencitaTraver, 1938). Both genera decreased in density after the hurricanes and were replaced with the BaetidaeCloeodes maculipesTraver, 1938 as the dominant taxon. This pattern was observed in both nymph and emerging adult densities.The secondary production of Leptophlebiidae species was highest before hurricane disturbance, with the BaetidaeC. maculipesshowing the opposite pattern.Neohagenulushad an annual production of 445 mg m⁻² year⁻¹,C. maculipesof 153 mg m⁻² year⁻¹andB. carmencitaof 68 mg m⁻² year⁻¹.Overall, the mayfly assemblages in our studied stream are vulnerable to hurricane disturbances. Expected increases in hurricane impacts might result in assemblage shifts that could change assemblage composition and alter energy flows within the ecosystem. 

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4. Cryptic CAM photosynthesis in Joshua tree ( Yucca brevifolia , Y. jaegeriana )

   https://doi.org/10.1111/nph.70437  

   Heyduk, Karolina; Sciulla, Sara; Hennessy, Bridget; Czymmek, Madeline; McAssey, Edward V; Kane, Chase; Kim, G Young; Sogunle, Ifeoluwa; Heublein, Lulu; Sriram, Dhriti; et al (August 2025, New Phytologist)

   Summary Joshua trees are long‐lived perennial monocots native to the Mojave Desert in North America. Composed of two species,Yucca brevifoliaandY. jaegeriana(Asparagaceae), Joshua trees are imperiled by climate change, with decreases in suitable habitat predicted under future climate change scenarios. Relatively little is understood about the ecophysiology of Joshua trees across their range, including the extent to which populations are locally adapted or phenotypically plastic to environmental stress.Plants in our common gardens showed evidence of Crassulacean acid metabolism photosynthesis (CAM) in a pilot experiment, despite no prior report of this photosynthetic pathway in these species. We further studied the variation and strength of CAM within a single common garden, measuring seedlings representing populations across the range of the two species.A combination of physiology and transcriptomic data showed low levels of CAM that varied across populations but were unrelated to home environmental conditions. Gene expression confirmed CAM activity and further suggested differences in carbon and nitrogen metabolism betweenY. brevifoliaandY. jaegeriana.Together the results suggest greater physiological diversity between these species than initially expected, particularly at the seedling stage, with implications for future survival of Joshua trees under a warming climate. 

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5. Longevity, Not Stream Flow, Explains Variation in Freshwater Mussel Growth Rates Across Four Rivers

   https://doi.org/10.1111/fwb.14373  

   Brunetz, Ian A; Lopez, Jonathan W; Hopper, Garrett W; González, Irene Sánchez; Atkinson, Carla L (January 2025, Freshwater Biology)

   ABSTRACT Freshwater mussels (Bivalvia: Unionida) are among the most imperilled freshwater taxa. Yet, there is a lack of basic life history information for mussels, including data on their growth and longevity. These data help inform conservation efforts, as they can indicate whether species or populations may be vulnerable to decline and inform which species may be best adapted to certain habitats. We aimed to quantify growth and longevity in five mussel species from four river systems in the southeastern United States and test whether growth was related to stream flow. We also interpreted our findings in the context of life history theory.To model mussel growth and longevity, we cut radial thick sections from the shells of mussels and used high‐resolution photography to image the shells. We identified annual growth rings (annuli) and used von Bertalanffy growth models to estimate growth rate (K) and maximum age (A_max) across 13 mussel populations. We then used biochronological methods to remove age‐related variation in annual growth in each shell. We tested whether annual growth was correlated with stream flow using discharge‐based statistics.We found substantial variation inKandA_maxamong species and among populations of the same species.Kwas negatively related toA_max. We did not find consistent correlations between annual growth and stream flow.Our estimates ofKandA_maxalign with previous studies on closely related species and populations. They also match the eco‐evolutionary prediction that growth rate and longevity are negatively related. Life history theory predicts that short‐lived species with higher growth rates should be better adapted to environments with cyclical disturbance regimes, whereas longer‐lived species with low growth rates should be better adapted to stable environments. The lack of correlation between annual growth and stream flow suggests that mussel growth may be limited by other factors in our study system.While some species seem to have relatively narrow ranges for growth and longevity, other species show wide variation among populations. This highlights the need for species‐ and population‐specific conservation efforts. Fundamental life history information can be integrated with other species traits to predict how freshwater taxa may respond to ecological threats. 

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