Frontiers in Ecology and Evolution

Individual-level differences in cumulative water stress drive threshold flowering responses in an endangered desert shrub

2026-03-27

Andrea P. Loayza, Danny E. Carvajal, Patricio García-Guzmán, Rodrigo S. Rios, Francisco A. Squeo

In arid ecosystems, plant reproduction is strongly constrained by water availability, yet individuals within the same population can differ in reproductive output despite experiencing similar climatic conditions. Understanding how spatial variation in water availability translates into differences in growth and reproduction is essential for predicting population persistence under increasing aridity. We tested the hypothesis that spatial heterogeneity in soil water availability generates individual differences in cumulative water stress that influence physiological performance, growth, and flowering in Myrcianthes coquimbensis, an endangered shrub of the Atacama Desert. Over a 15-month period, we monitored soil water potential, predawn leaf water potential, photosynthesis, vegetative growth, and reproduction in a natural population, where individuals were classified based on recent reproductive history as annual-flowering or sporadic-flowering. Cumulative water stress during the growing season was quantified using the Water Stress Integral (WSI), which integrates the magnitude and duration of plant water deficit. Soil water availability was spatially heterogeneous, and this heterogeneity was reflected in consistent differences in plant water status among individuals. Although photosynthesis declined with decreasing plant water status in both reproductive groups, annual-flowering individuals maintained higher mean photosynthetic rates and experienced significantly lower WSI than sporadic-flowering plants. Higher WSI was associated with reduced relative growth rates and marginally lower annual growth. Flowering probability increased sharply as WSI became less negative and exceeded 50% at approximately −90 MPa, indicating a threshold-like relationship between cumulative stress and reproduction. These results show that spatial heterogeneity in soil water availability within a single population can generate individual differences in WSI that translate into nonlinear variation in growth and flowering. By integrating short-term physiological responses over time, WSI provides a mechanistic link between environmental variability and reproductive outcomes in dryland plants.

Modern lacustrine cladocera and their controlling factors in Western Yunnan, SW China

2026-03-26

Qi Suo, Qifa Sun, Min Wang, Qian Shi, Wenjun Sun, Hongwei Meng, Linpei Huang, Caiming Shen

Plankton is crucial for lake ecosystem health. However, large-scale studies linking zooplankton communities, particularly cladocerans, to environmental factors remain scarce in China and worldwide. As one of the five lake regions in China, Yunnan is a key region for understanding past and present global lake plankton patterns and their relationships with environmental factors. This study presents an initial systematic investigation of modern cladoceran assemblages from 67 lakes in western Yunnan to reveal the pattern of modern cladoceran communities and their controlling factors. Modern cladoceran communities are primarily composed of planktonic taxa dominated by Bosmina. Their composition and abundance show a three-group pattern, i.e., cladoceran communities of groups I and II, dominated by planktonic taxa, are mainly from medium-deep lakes, whereas cladoceran communities of group III, dominated by littoral taxa such as Alona, are principally from shallow lakes. Community groups I and II are both dominated by Bosmina, but Group I is characterized by a dominance of Bosmina longirostris, whereas Group II is dominated by Bosmina longispina. Our study shows that water depth is the primary factor controlling this pattern, explaining 10.0% of the variation, while temperature acts as a secondary factor, explaining 4.2%; the water depth of ca. 8 m is a threshold to distinguish modern cladoceran communities dominated by planktonic taxa from ones dominated by littoral taxa, implying that modern cladoceran communities are associated with the availability of littoral habitats and thermal gradients. Our results highlight the critical roles of water depth and temperature in shaping zooplankton species composition and abundance patterns, providing a foundation for interpreting modern and fossil cladoceran assemblages in the context of environmental and climatic changes.

Structure, ecosystem services and economic evaluation of native tree diversity: a case study of the restored Aravalli Biodiversity Park, Delhi, India

2026-03-24

Amit Kumar, Yamini Gupt, Girish Chandra Pathak, Dushyant Kumar Rathore, Dinesh Alberstson, Md. Rizwan Khan, Mohammad Shah Hussain, Aisha Sultana, Cherukuri Raghavendra Babu

IntroductionTree diversity is important for maintaining environmental quality in tropical urban forests, but the composition, structure, and functional roles of these ecosystems are not yet fully understood. Urban blue-green spaces are gaining recognition for their ability to boost biodiversity and mitigate climate change. This study evaluates the diversity, structural features, and ecosystem services of the regenerated forest ecosystem in Delhi’s Aravalli Biodiversity Park, India.MethodsA vegetation assessment was carried out over a 500-acre area using 83 quadrats (10 × 10 m). A total of 829 native trees from 80 species were recorded. Phytosociological parameters such as Relative frequency, Relative density, Relative dominance, and Importance Value Index (IVI) were calculated to assess community structure. Growth attributes, including diameter at breast height (DBH), tree height, crown base height, crown width, and crown light exposure, were measured and analysed in relation to functional parameters such as carbon storage and sequestration.ResultsThe study revealed high species richness, evenness, and diversity, indicating a stable and well-balanced ecosystem. Phytosociological analysis showed a complex forest structure with diverse habitats. Growth parameters varied among species but were strongly interrelated. DBH, tree height, and crown width showed strong positive correlations with carbon storage and sequestration. The park contains approximately 202,100 trees, storing about 8,360 Mg carbon valued at Rs.11.34 crores. These trees sequester about 1,236 Mg C yr-1, prevent nearly three million litres of surface runoff, aiding groundwater recharge, and remove 126.89 Mg of air pollutants, providing benefits worth approximately Rs.1.89 crores.DiscussionThese findings highlight the ecological and economic value of restored tropical urban forests. Diverse and structurally complex green spaces, such as the Aravalli Biodiversity Park, play a significant role in climate change mitigation, pollution reduction, and sustainable urban environmental management.

The amino acid composition of mammalian mitochondrial proteins correlates with generation time

2026-03-20

Sankar Subramanian

Previous studies observed a correlation between the GC contents of the 12 mitochondrial protein-coding genes encoded on the H-strand and the generation times of mammals. However, how variation in GC content influences the amino acid composition of the proteins of these genes remains unclear. To examine this, we analyzed these mitochondrial proteins from 1,208 mammalian species. We first estimated the expected amino acid frequencies based on base frequencies at each codon position and then calculated the observed amino acid frequencies. The expected and observed proportions of almost half of the amino acids (8-9) showed a positive correlation with mammalian generation times, whereas the remaining amino acids (11-12) had a negative relationship. Accordingly, we categorized these amino acids as Group I and Group II, respectively. While the proportion of Group I amino acids showed a significant positive relationship with generation time, the magnitude of correlation was five times greater for highly variable amino acids than that observed for conserved amino acids. As expected, the opposite pattern was observed for the Group II amino acids. These findings are important because amino acid composition influences the structure and function of mitochondrial proteins. Our results suggest that for Group I amino acids, the magnitude of this influence is likely to be greater for mammals with long generation times (e.g., primates) than in those with short generation times (e.g., rodents).

Heat transfer in a realistic clutch reveals a lower efficiency in incubation of oviraptorid dinosaurs than of modern birds

2026-03-17

Chun-Yu Su, Jun-Yang Liao, Hsiao-Jou Wu, Kuan-Yu Chou, Ching Chen, Ming-Tsang Lee, Tzu-Ruei Yang

It has been proposed that some reproductive traits specific to birds, such as thermoregulatory contact incubation (TCI), may also have been present in oviraptorosaurians, as inferred from clutch-associated oviraptorid adults with postures resembling avian brooding behavior. Nevertheless, prerequisites for TCI, such as the incubating adult providing the majority of heat needed for normal embryonic development, have not been evaluated with respect to their body and egg dimensions. To test this, a realistic Heyuannia huangi incubator, oviraptorid clutches, and heat transfer numerical simulations were developed to simulate the brooding behavior of Heyuannia huangi and Nemegtomaia barsboldi. Our results indicate that the incubator could only partially contact the outer-ring eggs of the clutch, leading to a temperature difference between the inner and outer rings and a lower incubation efficiency compared to that of extant birds. Additionally, an outer-ring egg had a considerably higher temperature than the superimposed inner-ring egg when positioned near the incubator’s core, whereas an outer-ring egg had approximately the same temperature as the superimposed inner-ring egg when positioned closer to the incubator’s periphery. If Nemegtomaia barsboldi were to initiate incubation before clutch completion, the temperature distribution could cause the outer-ring egg at the incubator’s core to hatch earlier than the inner-ring egg immediately beneath it, whereas at the periphery the inner-ring egg could hatch earlier than the outer-ring egg immediately above it. However, irrespective of position, the inner-ring egg of Heyuannia huangi may hatch earlier than the outer-ring egg immediately above it. Our findings do not support the TCI hypothesis and instead, they suggest that oviraptorids co-regulated incubation with environmental heat, with the adult stabilizing clutch temperatures, reducing thermal extremes, and influencing patterns of asynchronous hatching.

Editorial: Conservation and restoration in the oceans

2026-03-10

Carlos Prada, Jesús Ernesto Arias-González

Wild vs. captive: a multidimensional review of biological differences and conservation implications

2026-03-09

Xiwei Jin, Rengui Li, Shijie Mou, Zhiguo Cui, Desheng Li

The conservation of endangered species increasingly relies on captive breeding programs, yet fundamental differences between captive and wild environments create complex challenges for successful species management and reintroduction. This comprehensive review synthesizes current knowledge on the multidimensional differences between wild and captive animals across physiological, genetic, microbial, and ecological domains. We examine how captive conditions alter metabolic regulation, immune function, and reproductive physiology, often resulting in more stable but potentially less adaptive phenotypes. Genetic analyses reveal that while some captive populations maintain diversity comparable to wild counterparts through careful management, many suffer from founder effects, genetic drift, and reduced functional gene diversity. Microbiome studies demonstrate systematic shifts in gut microbial communities, with captive animals typically showing altered diversity patterns and functional capabilities that may compromise their ability to process natural diets and resist pathogens upon release. Ecological adaptations manifest through morphological plasticity, cognitive changes, and behavioral modifications that reflect responses to simplified captive environments. These findings have profound implications for conservation strategies, highlighting the need for integrative approaches that combine rigorous genetic management, environmental enrichment, and species-specific reintroduction protocols. We conclude that successful conservation requires understanding these multidimensional differences to develop more effective captive breeding programs and optimize reintroduction success rates, ultimately advancing long-term species conservation and ecological restoration efforts.