Ecology

Segrestin, Jules; Lisner, Aleš; Götzenberger, Lars; Hájek, Tomáš; Janíková, Eva; Jílková, Veronika; Konečná, Marie; Švancárová, Tereza; Lepš, Jan

doi: 10.1002/ecy.70091pmid: 40342156

Biodiversity loss poses a significant threat to ecosystem functioning. However, much of the empirical evidence for these effects is based on artificial experiments that often fail to simulate the structure of natural communities. Hence, it is still unclear whether natural diversity losses would significantly affect the functioning of “real‐world” ecosystems. As subordinate and rare species constitute most of the diversity in natural communities and are often more vulnerable to local extinction, we evaluated their contribution to ecosystem functioning in a naturally species‐rich grassland. We focused on two mechanisms by which they can support ecosystem functions: redundancy and complementarity. We conducted two long‐term field experiments (>6 years) simulating contrasting biodiversity loss scenarios through the manual removal of plant species and measured the consequences of species loss on various ecosystem functions related to carbon dynamics. The latter were examined seasonally to explore diversity effects outside the typical peak of vegetation. We found that dominant removal led to substantial reductions in aboveground phytomass and litter production and altered the annual carbon fixation capacity of the vegetation, highlighting the pivotal role of dominant species in driving ecosystem functioning. Despite high species diversity, other species could not fully compensate for the loss of a single dominant even after more than 25 years, challenging assumptions about redundancy. Complementarity effects were not detected at the peak of vegetation but were evident in early spring and autumn when subordinate and rare species enhanced ecosystem functions. Surprisingly, belowground phytomass, soil organic carbon content, and litter decomposition were unaffected by species removal, suggesting complex interactions in belowground processes. These findings underscore the importance of dominant species in maintaining ecosystem functioning and emphasize the need for nuanced approaches to studying biodiversity loss in real‐world communities. Comprehensive seasonal measurements are essential for accurately discerning the effects of biodiversity on ecosystem dynamics and informing effective conservation strategies that maintain ecosystem functioning.

Castro‐Arrazola, Indradatta; Sánchez‐Piñero, Francisco; Moretti, Marco; Hortal, Joaquín

doi: 10.1002/ecy.70106pmid: N/A

Ecological communities under extreme environments are shaped by a balance of environmental filtering and coexistence mechanisms that result in a series of assembly rules. Although there is abundant evidence about the importance of these community assembly mechanisms in plants, their effects have been seldom compared for animals. We assess their relative importance for the temporal and spatial responses of dung beetle communities along a strong aridity gradient in the edge of the Sahara. Specifically, we study how phylogenetic and functional community structure varies with aridity in space and time and combine it with selected traits to assess the relative importance of mechanisms associated with known assembly rules along the gradient, including whether increasing aridity selects for specific trait values. We surveyed a 400‐km gradient toward the Sahara in the dry and wet seasons of two consecutive years, gathering phylogenetic information and quantifying traits related to aridity from direct measurements and the literature. We calculated metrics of functional and phylogenetic diversity, the decoupled variation in functional diversity, functional and phylogenetic beta diversity, their standardized effect sizes based on null models, and community weighted means for all relevant traits. Then, we assessed the relationships between the spatial and temporal variations in these facets of diversity through linear models, independent principal components analyses, and multiple ANOVAs (MANOVAs). Increasing aridity filters dung beetle communities at the phylogenetic and functional levels, selecting particular trait syndromes in both space and time, as communities change similarly toward the Sahara and between the wet and dry seasons. Contrary to expectations, phylogenetic and functional structure shows a continuous replacement with aridity rather than a nested loss of lineages and trait values, which is not accompanied by a reduction in trait volume along the gradient. Only the hyperarid conditions of the dry season show reductions in trait volume. This implies that responses to aridity lead to assemblages with a common adaptive strategy, dominated by saprophagous species with longer wings and endocoprid behavior, associated with the acquisition of ephemeral resources in the poor desert environment. In addition, animal communities can respond to rapid ecosystem breakdowns if their phenological amplitude includes extreme conditions.

Li, Ping; Jia, Zhou; Wu, Yuntao; Chang, Pengfei; Jalaid, Nairsag; Guo, Lulu; Pan, Shengnan; Wang, Shaopeng; Jiang, Lin; Hu, Shuijin; Liu, Lingli

doi: 10.1002/ecy.70105pmid: 40390210

Precipitation fluctuations strongly influence biomass production and its stability of terrestrial ecosystems. However, our understanding of the extent to which plant communities adjust their water‐use strategies in response to non‐growing season precipitation variations remains limited. Our 5‐year snow manipulation experiment in a semi‐arid grassland, complemented with paired stable isotope measurements of δ18O and δ13C for all species within the community, demonstrated that the impact of snowmelt on plant physiological activities extended into the peak growing season. Deepened snow enhanced ecosystem water use efficiency (WUE), biomass production, and its temporal stability. We further examined whether the observed increase in biomass stability was associated with the functional diversity of plant water‐use strategies. Plant cellulose Δ18Ocell analysis revealed that both community‐weighted mean and functional dispersion of stomatal conductance were positively associated with biomass production and its stability. The δ13C results further indicated that even with increased stomatal conductance, grasses were able to maintain their high intrinsic WUE by increasing photosynthesis more than transpiration. This resulted in higher biomass and greater dominance of high‐WUE functional groups under deepened snow. In addition, we also found that deepened snow increased root biomass, particularly in the 0‐ to 5‐cm and 20‐ to 40‐cm soil layers. This increase in root biomass enhanced the uptake of snowmelt from both surface and deep soil layers, further contributing to community stability. Overall, our study demonstrates that plant communities can optimize water acquisition and utilization, thereby enhancing the stability of biomass production through coordinated changes in plant physiology, species reordering, and root distribution under altered snow regimes.

Adams, Carrie Ann; Tomaszewska, Monika A.; Henebry, Geoffrey M.; Horton, Kyle G.

doi: 10.1002/ecy.70110pmid: 40383990

Several factors are known to affect bird migration timing, but no study has simultaneously compared the effects of temperature, land surface phenology, vegetation greenness, and relative humidity in both spring and fall. In addition, it is unclear whether long‐term shifts in migration phenologies have kept pace with changing climates. For example, if migration shifts earlier in the spring, temperatures on migration dates may remain stable over time despite spring warming trends. If the phenologies of birds, plants, and insects shift asynchronously in response to changing climates, then birds may encounter reduced resource availability during migration. We estimated spring and fall 10%, 50%, and 90% cumulative migratory passage dates at 53 weather surveillance radar stations across the US Central Flyway. We determined which conditions (temperature, timing of green‐up and dormancy, relative humidity, and enhanced vegetation index [EVI]) explained annual variation in migration phenologies. We also described decadal trends in environmental conditions and whether shifts in migration phenologies were sufficient to compensate for these changes. Annual changes to spring migration phenologies were best explained by anomalies in temperature, with earlier passage in warmer years. Fall migration occurred later on warmer, more humid years with higher EVI and later dormancy. Long‐term adjustments in bird migration phenologies did not mitigate their exposure to changing environmental conditions. Although passage dates for all spring migration quantiles advanced significantly (~0.6 days/decade), temperatures on spring 10% passage dates increased, while 50% and 90% passage occurred closer to green‐up. In the fall, temperatures increased on 50% and 90% passage dates. By contrast, the advancement of 10% passage (~1 day/decade) prevented early migrants from experiencing the cooling late‐summer temperature trend. Warmer temperatures in mid to late fall may lead to earlier fruiting phenology and asynchronies with migratory passage, which occurred later in warmer years. Changes in temperature and land surface phenophases experienced by migrants suggest that resource availability during migration has changed and that adjustments to migration phenologies have not compensated for the effects of changing climates.

Murray, Paulina E.; Clark, Peter W.; Fraver, Shawn; D'Amato, Anthony W.; Adair, E. Carol

doi: 10.1002/ecy.70087pmid: 40331350

Global hydrological cycles are shifting due to climate change, and projected increases in the frequency and intensity of extreme precipitation events will likely affect essential ecosystem processes driven by climate, such as forest decomposition. Our objective was to determine the effects of drought and intense rainfall on leaf litter and wood decomposition rates. We used a precipitation manipulation experiment to demonstrate that extreme precipitation projections for the Northeastern United States will significantly impact wood but not leaf litter decomposition and that variations in substrate quality will continue to drive differences in decomposition rates. We found that drought and high rainfall reduced wood decomposition compared to historic rainfall patterns. The median mass remaining of wood stakes after three years within drought, control, and inundation treatments was 84.2%, 57.0%, and 67.5%, respectively. Furthermore, labile litter and wood substrates decomposed more rapidly than recalcitrant substrate types. Thus, our findings suggest a greater sensitivity of wood decomposition to changing precipitation regimes compared to leaf litter. Since wood represents a substantial forest carbon pool, our results underscore the possible significant impacts of projected extreme precipitation scenarios for forest functions, including carbon cycling and sequestration.

doi: 10.1002/ecy.4344pmid: N/A

COVER PHOTO: The cover image shows an adult click beetle, Agrypnus murinus, a species common in grasslands of the northern hemisphere, sitting on a blade of grass. The photo was taken in May 2022 at the Jena Experiment field site, a long‐term grassland biodiversity experiment. This beetle is one of many arthropods featured by Bröcher et al. (Ecology, Volume 106, Issue 4, Article e70077; doi:10.1002/ecy.70077) in their data paper which compiles trait data for over 1,300 species, including coleopterans, arachnids, hemipterans, hymenopterans, isopods, myriapods, and orthopterans. The traits span feeding ecology, habitat requirements, flight capability, and size, offering a comprehensive resource for exploring arthropod functional roles in grassland ecosystems. Photo credit: Maximilian Bröcher.

Ueda, Rui; Kanaiwa, Minoru; Terui, Akira; Takimoto, Gaku; Sato, Takuya

doi: 10.1002/ecy.70114pmid: 40383987

Life‐history variation can contribute to the long‐term persistence of populations; however, it remains unclear which environmental factors drive life‐history variation within a population. Seasonally recurring resource subsidies are common in nature and may influence variations in recipient consumers' life‐history traits. In this study, we experimentally demonstrated that terrestrial invertebrate subsidies occurring early in the growing season facilitated consumer individuals to adopt fast growth. In contrast, fewer consumer individuals adopted fast growth when subsidies occurred late in the growing season. Consumer individuals that adopted fast growth matured early at age 1, suggesting that the observed variation in life history emerged along with a fast–slow life‐history continuum. The estimated survival probability was lower in consumer individuals from the faster growth cluster in the no‐supply treatment (control), suggesting a growth–survival trade‐off. However, the growth–survival trade‐off became unclear in the early‐supply treatment and even reversed in the late‐supply treatment. As a result, the frequency of consumer individuals maturing at age 1 was higher in the early‐supply treatment than in the late‐supply treatment and no‐supply treatment, implying a higher short‐term population growth with the early subsidies. Our findings highlight that seasonal ecosystem linkages through resource subsidies help us understand how life‐history variation can be maintained within a population at the landscape scale.

Scurfield, Daniel J.; Gross, Phoebe L.; Gan, Julian C. L.; Moore, Jonathan W.

doi: 10.1002/ecy.70100pmid: 40342189

Gérard, Sylvain; Decaëns, Thibaud; Marchán, Daniel F.; Beauchesne, Marie; Berlioz, Laurent; Capowiez, Yvan; Clause, Julia; Decaëns, Luis; Dellavedova, Raphaël; Duhaut, Clément‐Blaise; Garnier‐Fière, César; Goulpeau, Arnaud; Goussopoulos, Juliette; Iannelli, Maeva;

Levitan, Don R.; Olsen, Kevin C.; Best, Rachael M.; Edmunds, Peter J.

doi: 10.1002/ecy.70102pmid: 40344585

The abundance of many Caribbean corals has declined over the past few decades, yet now Porites astreoides is more common on many shallow reefs than in the 1980s and shows evidence of local adaptation. We compare the small‐scale (1–8000 m) genetic structure of this brooding species and the broadcasting coral Orbicella annularis on reefs (<14 m depth) in St. John, US Virgin Islands, to examine how larval dispersal and asexual propagation contribute to the retention of genotypes within reefs. Populations of P. astreoides have genetic structure across reefs separated by a few 100 m, increased relatedness within reefs, and parthenogenetic larval propagation confirmed by parent–offspring genotyping. Within reefs, P. astreoides colonies <1 m apart are more related, independent of clonal reproduction, than corals at greater distances. In contrast, O. annularis lacks across‐reef genetic structure, has low relatedness within and among reefs, and does not produce asexual larvae. Small‐scale genetic structure and high relatedness in P. astreoides are evident even without considering asexual propagation, but asexual reproduction enhances these differences. Neither species shows the genetic signature of inbreeding or reduced genotypic diversity despite the high within‐site relatedness of P. astreoides. Monitoring on these reefs from 1987 indicates that Porites has increased in abundance while Orbicella has decreased in abundance. The success of Porites is due to greatly increased settlement and recruitment compared with Orbicella. Together these results indicate that high numbers of locally retained and successful genotypes might explain the relative success of Porites on shallow, present‐day reefs in the Caribbean.