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1. Loss of native herbivores triggers diversity decline of ephemeral plant communities

   https://doi.org/10.1111/jvs.13210  

   Fernández‐Murillo, María_del_Pilar; Alfaro, Fernando Daniel; Craven, Dylan; Gutiérrez, Julio Roberto; Kelt, Douglas A; Meserve, Peter L; Troncoso, Alejandra J (September 2023, Journal of Vegetation Science)

   None (Ed.)

   Abstract AimEvaluate the temporal changes in species diversity, composition, and structure of ephemeral plant communities and the seed bank in response to long‐term herbivore exclusion over 11 years in plots with and without herbivores. LocationNorth‐central Chile. MethodsWe obtained information on ephemeral vegetation cover in August and September using the intercept point method and recorded seed abundance in April. The Bosque Fray Jorge National Park Long‐Term Socio‐Ecological Research (LTSER) provided these records covering 11 years (2009–2019). From the original experiment of 20 plots, we used eight plots divided into two treatments: four plots allowed free access to all herbivores (with herbivores), while the other four plots excluded herbivores (without herbivores). ResultsWe found that Hill–Shannon diversity increased in plant communities with herbivores and a temporal increase in the cover of the dominant species,Plantago hispidula, under herbivore exclusion. In wet years, species richness and temporal turnover of plant communities increased independently of treatment. Although seed abundance differed among treatments and years, population structure remained constant over time and among treatments, suggesting that the seed bank acts as a buffer against shocks that modify plant community dynamics. Structural equation modeling revealed that precipitation, via its positive effects onPlantago hispidula, increases native plant richness to a greater extent than herbivores. However, in the absence of herbivores, precipitation directly affects native species richness. Moreover, we found that precipitation also influences the native species richness of the seed bank, both directly and indirectly, although its impacts exhibit a time lag. ConclusionsOur study demonstrates that the temporal dynamics of ephemeral plant communities and seed banks in semi‐arid ecosystems are strongly coupled to climate variability, highlighting the vulnerability of these communities to biodiversity loss and climate change. 

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2. Effects of elevated nutrient supply on litter decomposition are robust to impacts of mammalian herbivores across diverse grasslands

   https://doi.org/10.1007/s00442-025-05791-4  

   Keller, Adrienne B; Borer, Elizabeth T; Buyarski, Christopher R; Cleland, Elsa E; Gill, Allison; MacDougall, Andrew S; Moore, Joslin L; Morgan, John W; McCulley, Rebecca L; Risch, Anita C; et al (October 2025, Oecologia)

   Abstract Litter decomposition is one of the largest carbon (C) fluxes in terrestrial ecosystems and links aboveground biomass to soil C pools. In grasslands, decomposition drivers have received substantial attention but the role of grassland herbivores in influencing decay rates is often ignored despite their potentially large effects on standing biomass and nutrient cycling. Recent work has demonstrated that nutrient addition increases early-stage decay and suppresses late-stage decay. Mammalian herbivores can mediate the effects of nutrient supply on biomass, suggesting herbivores may alter the effects of nutrients on decomposition, though this is largely unknown. We examined how herbivory mediates the effects of nutrient supply on long-term decomposition across 19 grassland sites of the Nutrient Network distributed experiment. At each site, a full-factorial experiment of combined nitrogen (N), phosphorus (P), and micronutrient (K) enrichment (‘control’ or ‘ + NPK’) and mammalian herbivore (> ~ 50 g) exclusion (‘unfenced’ or ‘fenced’) was carried out in a randomized block design. We hypothesized that nutrient effects on litter decomposition would be strongest where herbivores caused the greatest reductions in aboveground plant biomass (i.e., at sites with more intense herbivory). After accounting for wide variation in decomposition rates across sites, we found that, within sites, elevated nutrients increased early-stage decay and suppressed late-stage decay. In contrast, neither herbivore exclusion (i.e., fencing) nor site level changes in aboveground biomass due to herbivory altered the nutrient effects on decomposition rates. Across grasslands, our results indicate that elevated nutrient supply modifies litter decomposition rates independent of herbivore impacts. 

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3. Plant community response to warming and herbivory on sub-arctic coastal terraces in Western Alaska, 2015 - 2016

   https://doi.org/10.18739/a2hm52m2s  

   Beard, Karen; Choi, Ryan (January 2017, NSF Arctic Data Center)

   To predict future changes in high latitude biomes, it is important to understand how plant communities will respond to increased temperature. Across sub-arctic systems, warming generally increases aboveground biomass in plant communities. Specifically, in arctic graminoid systems, experimental warming has been shown to increase productivity, aboveground biomass and leaf litter production, and stimulate early-season growth. Warming can also decrease species richness, and reduce foliar nitrogen (N) in aboveground biomass over the growing season. Migrating geese are important grazers in arctic and subarctic ecosystems during summer breeding months. Avian herbivores depend on high quality forage (high N) and are often found at high enough densities to impact vegetation communities. Exclosure experiments show that goose herbivory reduces biomass of herbaceous species but increases net above-ground primary production and N concentrations of grazing-tolerant sedges, and sometimes even increases species richness. Goose herbivory also alters plant physiological processes as evidenced by increased N uptake by plants, as well as the biophysical processes that affect N cycling through trampling and fecal deposition. Thus, high-density populations of avian herbivores can have top-down control on their vegetation communities. While increasing global temperatures may increase aboveground biomass and decrease species richness in plant communities, herbivory could potentially mediate, or even reverse, these responses. For example, Post and Pedersen (2008) suggest that herbivory may exacerbate plant response to warming because both effects increase rates of productivity, while simultaneously reducing the effects of warming on aboveground biomass. If the interaction between warming and herbivory causes a shift in plant abundance and community functional groups, this could cascade through the system resulting in changes in nutrient cycling and plant-animal feedbacks. The Yukon-Kuskokwim (Y-K) Delta is one of the largest river deltas in the world and is a globally important breeding area for millions of long-distance migratory waterfowl and shorebird species. The majority of these species nest in high densities close to the ocean among lowland coastal habitat. Geese populations utilize overlapping habitats and shift from more coastal to more interior habitats over the growing season. The expectations for how vegetation responds to increasing temperature and changes in herbivory with climate change will vary for different plant communities. We propose to conduct an experiment that investigates the impact of warming and herbivory on three coastal sub-arctic vegetation communities in the Y-K Delta addressing the following questions: 1) How does warming impact vegetation biomass and community composition; 2) How does herbivory impact species composition and plant functional groups; and 3) How do the different responses to warming and herbivory interact? 

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4. Trait-Based Investigation Reveals Patterns of Community Response to Nutrient Enrichment in Coastal Mesic Grassland

   https://doi.org/10.3390/d13010019  

   Brown, Joseph K.; Zinnert, Julie C. (January 2021, Diversity)

   null (Ed.)

   Despite recent advances, we still do not understand how chronic nutrient enrichment impacts coastal plant community structure and function. We aimed to clarify such impacts by testing for differences in ecosystem productivity and multiple community metrics in response to fertilization. We established plots in 2015 consisting of control (C), nitrogen (N), phosphorus (P), and nitrogen + phosphorus (NP) treatments in a mid-Atlantic coastal grassland. In 2017 we collected aboveground biomass, functional traits, and species abundance for each plot. Our findings indicate a synergistic co-limitation, such that NP plots were more productive than all other treatments. A combination of traits responsible for competition and nutrient uptake (i.e., height and δ15N) caused trait-based divergence of N and NP plots from C and P plots. Functional trait-based composition patterns differed from species composition and lifeform abundance patterns, highlighting complexities of community response to nutrient enrichment. While trait-based functional alpha-diversity did not differ among nutrient treatments, it was positively correlated with biomass production, suggesting nutrients may impact functional alpha-diversity indirectly through increased productivity. Increased functional alpha-diversity could be a mechanism of co-existence emerging as productivity increases. These results have important implications for understanding how plant communities in low-productivity coastal systems are altered by fertilization. 

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5. Isolated Trees in a Fragmented Tropical Landscape: A View Through the Soil Seed Bank

   https://doi.org/10.1111/btp.70086  

   Allbee, Samantha A; Camargo, Paulo_H_S A; Jordan, Adriana J; Carlo, Tomás A (September 2025, Biotropica)

   ABSTRACT Tropical soil seed banks under isolated trees in pastures remain relatively understudied despite their important role in forest regeneration. Here, we investigated patterns of plant species diversity, abundance, and composition in the soil seed banks of cattle pastures, under fleshy‐fruited, and nonfleshy‐fruited trees within pastures, and in secondary forest patches at ten study sites in Brazil. We also examined how the fruit traits of isolated trees affected seed bank communities, predicting that fleshy‐fruited trees are more connected to frugivory and seed dispersal networks than trees without fruit resources, and would therefore have richer seed banks. We found that the species richness and diversity of seed bank communities were higher in secondary forest patches and under fleshy and nonfleshy‐fruited trees compared to soil samples from open pastures, although early successional plants were dominant across all habitats. The fruit traits of isolated trees also affected the richness of seeds dispersed by animals and abiotically. Seed banks under fleshy‐fruited trees had more seeds of bird‐dispersed plants compared to nonfleshy‐fruited trees. Overall, our results show that soil seed banks under isolated trees are more similar to those in secondary forest patch seed banks, especially trees bearing attractive fruit resources that likely increase connectivity to frugivory and seed dispersal networks active in fragmented landscapes. 

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