Ecology最新文献

The trunks of forest trees store massive amounts of carbon, but fungi actively and invisibly decay wood inside even seemingly healthy trees. Wood-decay fungi are responsible for the loss of stored carbon in living trees, and they make trees susceptible to snapping and uprooting in storms. We used sonic tomography to measure the prevalence and severity of decay in 1744 live trees (≥20 cm diameter) of 171 species on the 50-ha Forest Dynamics Plot on Barro Colorado Island, Panama. A median of <2% of the cross-sectional trunk area showed decay, but 15% of trees had >20% decay. Twenty percent of the combined basal area showed decay, representing a loss of approximately 1% of aboveground biomass. Larger trees more often showed internal decay, with one quarter of trees showing decay before reaching canopy height. Decay severity varied by species; 23% of species showed <2% decay while 9% of species lost over half their basal area. Rare species were more affected than locally abundant species, and species with traits associated with a fast life history were more susceptible to decay. These results suggest that hidden wood decay affects a large proportion of living tropical forest trees.

Advanced spring flowering relative to climate change has been widely documented, but studies on flowering duration remain limited due to a lack of comprehensive data. This study analyzed phenological data (1970–2021), including first and full flowering dates of seven temperate tree species across 16 locations in Korea. Trends in flowering phenology were assessed using day of year (DOY) values, and floral seasonality was evaluated at regional and national scales. We found that full flowering dates advanced more rapidly than first flowering dates for most species, resulting in shortened flowering durations. These trends suggest potential shifts in the floral community structure, including reduced connectivity of flowering times among species with non-overlapping flowering seasons. Nationally, regional variation of flowering times across all species has significantly decreased in recent years (2010–2021) compared to the two preceding 20-year periods. The observed changes in flowering times may have consequences, such as (1) reduced pollination opportunities due to shorter plant reproductive periods, (2) decreased food resources for pollinator insects, and (3) shortened harvesting periods for migratory beekeepers. Although our analysis focused on a limited number of species, the potential impacts identified highlight the need for strategies to manage plant–pollinator mismatches for better pollination services.

Understanding the mechanisms that maintain the coexistence of plant species is critical to addressing the global biodiversity crisis. Increasing attention has been paid to interactions between plants and soil microbes (plant–soil feedback, PSF), which can not only promote plant coexistence by increasing stabilizing effects but also hinder it by generating competitive fitness differences. However, the predictive power of the PSF has been questioned in recent studies because estimates of microbially mediated coexistence have correlated poorly with the outcomes of plant interactions observed in the field. This discrepancy may be due to the approaches typically used in PSF research, such as measuring PSF effects on a single vital rate or using soil conditioned for a short time period and without considering abiotic contexts. Here, I examined the effects of soil inoculum with different training histories and training environments (with and without added nutrients) on germination, seedling survival, and biomass of four grassland species. I then examined whether predictions of microbially mediated coexistence of four species pairs were sensitive to the vital rate identity, conditioning history, and soil training environment. I found that conspecific inoculum trained for longer had increasingly positive and negative effects on germination and biomass, respectively, although the effects of inoculum history varied across species and training environments. Estimates of microbially mediated outcomes were directly related to the vital rate used: when based on biomass and seedling survival, all four pairs were predicted to coexist, but only two pairs could do so when based on germination due to much reduced or even negative stabilization. Although coexistence predictions were not significantly related to conditioning history (including the effects of both variable conditioning durations and combinations of conditioning species) or nutrient treatments, both factors had a significant effect on stabilization. These results suggest that predictions of microbially mediated coexistence may be biased when based on a single vital rate, such as plant growth. To obtain more realistic and accurate outcome estimates, PSF effects should be integrated across different life stages, considering the temporal and abiotic contexts of these effects specific to a focal study system.

Understanding the relationships between species' demography and functional traits is crucial for gaining a mechanistic understanding of community dynamics. While leaf morphology represents a key functional dimension for plants worldwide (i.e., the leaf economics spectrum), its ability to explain variation in trees' life history strategies remains limited. Plant growth is influenced by both leaf morphology and allocation; hence, incorporating both dimensions is essential but rarely done. Additionally, trait–performance relationships have mainly been studied in tropical communities, leaving gaps in our understanding of temperate forests where different seasonality patterns may alter these relationships. We examined whether species' leaf area index (leaf area per crown size, LAI), a measure of leaf allocation, explains the variation of juvenile tree species' potential growth rates in a winter-deciduous broadleaf forest. LAI has not been characterized as a species-level trait, but its ability to predict plant productivity at the ecosystem scale highlights its potential for explaining plant growth. We evaluated species' maximum LAI both individually and in conjunction with wood density (WD) and leaf mass per area (LMA). We expected that models would improve when both leaf morphology (LMA) and leaf allocation (LAI) were included and that species with denser crowns would have higher potential growth rates. LAI and LMA were significant predictors of growth but only when both were incorporated, and together explained a high proportion of species' growth variations (R²_adj = 0.59). We found evidence of a trade-off between LAI and LMA, with a negative relationship between them and each having a positive influence on species' growth, suggesting that there are multiple allocation strategies to achieve fast growth. A surprisingly positive LMA–growth relationship contrasts with observations from tropical forests. We did not find significant relationships with WD in this forest. Our results highlight that incorporating leaf allocation improves models of trait–performance relationships. They also suggest, in agreement with the limited literature, that temperate forests may exhibit different trait–performance relationships from those of tropical forests, where LMA is negatively related to growth and WD is often important. Clarifying the details and contexts of trait–performance relationships is crucial for applying the functional trait framework to understanding community structure and dynamics of forests globally.

This data set includes measurements of aboveground plant biomass (in grams per square meter), percent alive and dead, composition (percent graminoid [grasses, sedges, rushes] and non-graminoid [other monocots, dicots]), and carbon and nitrogen content (in parts per million) of aboveground biomass collected during three studies (1988 and 1989; 1999–2001; 2012–2014) at grasslands grazed by herds of elk (Cervus canadensis), bison (Bison bison), and pronghorn (Antilocapra americana) in Yellowstone National Park. A total of 25 different grasslands were sampled during the studies. At each grassland, measurements were made outside and inside small (1.5 × 1.5 m) temporary exclosures moved approximately monthly throughout each growing season to determine ungulate consumption and aboveground production. Plant data were also gathered at a subsample of 13 of the grasslands inside permanent exclosures erected during the summer before each study. Monthly aboveground plant P content (in parts per million) is also provided at six sites in 2013 and 2014. Location (latitude, longitude), elevation, and 0 to 10 cm total soil C and N are included for all the sites. There are no copyright or proprietary restrictions on the data; please cite this data paper when using the data in other works.

The Earth's grasslands have experienced extensive alterations to their grazing regimes over the course of human history. We asked how native grassland herbivores (bison, prairie dogs, and grasshoppers) and a non-native herbivore that has become dominant (cattle) affect seasonal patterns of plant and soil elemental chemistry and aboveground plant biomass in a shortgrass prairie in the North American Northern Great Plains. To quantify herbivore effects, we sampled plants and soils across 4 months of the growing season in 15 grassland sites comprising five herbivore regimes with varying densities of bison, cattle, prairie dogs, and grasshoppers. Prairie dogs had the strongest herbivore effects on grass and soil chemistry, increasing grass N, K, and Mg, and increasing soil C and N. Both bison and cattle grazing increased grass Mg and decreased grass Si. Sites with higher grasshopper densities had higher soil P. Finally, the seasonal trajectory of aboveground plant biomass was altered by the use of insecticides in prairie dog towns, with the biomass at these sites peaking near the end of the growing season. Plant biomass peaked in mid-summer in all other herbivore regimes, with declines in the late growing season. This suggests that Orthopteran herbivores, taxa that tend to eat more in the late season when they are often in the adult stage, may have an overlooked contribution to seasonal aboveground plant biomass trajectories in temperate grasslands. Conservation and rewilding of grassland herbivores can maintain the critical nutrient cycling services that these taxa provide.

Recent evidence suggests that parasite-mediated reductions in food intake (i.e., anorexia) in herbivores can trigger trophic cascades that increase producer biomass. This outcome assumes homogeneous host responses to parasite infection; however, individual variation in parasite-mediated anorexia is common. To understand the potential consequences of such variation, we quantified individual variation in host feeding responses to parasitism empirically using a wild herbivore–helminth system. We then evaluated the impact of ecologically relevant levels of variation in anorexia on producers using stochastic individual-based models composed of parasites, herbivores, and plants. Our empirical data showed that although higher helminth burdens were associated with lower population-level feeding rates, there was considerable individual variation in the presence and magnitude of anorexia. Our models revealed a pronounced effect of variation in anorexia prevalence but not magnitude on plants. Plant biomass increased as anorexia became prevalent in the herbivore population, and there was a strong dampening effect of anorexia prevalence on plant biomass variance, suggesting that parasite-mediated anorexia in herbivores can stabilize producer population dynamics. Interestingly, the association between higher anorexia prevalence and lower variance in plant biomass was due, in part, to negative feedback between herbivore feeding rates and helminth ingestion, suggesting that negative feedback between host behavior and parasitism, a phenomenon that can help stabilize certain host–parasite interactions, may have stabilizing effects that extend to other members of the ecological community via trophic cascades.

Natal dispersal is a key process in ecology and evolution. Similarities of dispersal patterns between relatives can lead to small-scale kin structure within populations with consequences for population dynamics and genetics. Most studies have focused on birds, lizards, and small mammals. How family effects may shape sex-specific natal dispersal patterns in a large-sized social mammal remains unexplored. We fill this gap thanks to a 30-year-long monitoring of a wild boar population. This polytocous, polygynous, and size dimorphic species displays a matrilineal social organization. From the monitoring of individuals from early life to adulthood, we characterized natal dispersal patterns by investigating the propensity to disperse and the dispersal distance. As expected for a species subjected to strong sexual selection, offspring males dispersed more often and farther than females. Looking specifically at similarities of dispersal patterns among relatives within a group, we found that offspring females from the same family displayed more similar dispersal propensity and distance than females from different groups, highlighting family effects. However, this dispersal pattern did not hold for males. Family effects can thus shape natal dispersal patterns in a sex-specific way in social mammals and are key to understanding individual variation in dispersal patterns.