Journal of Ecology

We synthesize the rich empirical information on seed dispersal distances to provide standardized dispersal kernels for 168 case studies and generalized kernels for plant growth form/dispersal mode combinations. Potential uses include the following: (i) choosing appropriate dispersal functions in mathematical models; (ii) selecting informative dispersal kernels for one's empirical study system; and (iii) using representative dispersal kernels in cross-taxon comparative studies.

We studied the effects of forest fragmentation on plant–frugivore interactions and tested for associations between fragmentation and response and effect traits of frugivores. Despite the absence of large-bodied and forest-dependent frugivores in fragmented forests, frugivore-mediated seed dispersal of plants remained unaffected. These findings highlight the importance of forest generalists and small-bodied frugivores for maintaining dispersal processes in fragmented forests. Photo: S. Rösner / pixeldiversity.com

Our simulation results show that variation of the pollen pool composition at the scale of individuals or stigmas due to spatial configurations or pollen limitation can substantially modify hybridization rates. We explain this by the disproportionate effect of some pollen environments on average hybridization rates. This suggests thoroughly evaluating individual behaviour in terms of hybridization, especially for rare or patchy species.

A few highly fertile trees dominated reproduction in the stand. Differential recruitment success tended to reduce their initial advantage, however, suggesting that reproductive inequality might rapidly decline as more trees start to reproduce along the expansion process. Our results also suggest that field estimates of size or seed production are unlikely to provide reliable estimates of lifetime reproductive success in trees.

Disregarding genotyping errors and null alleles can produce biased and less accurate estimates of the rates at which present-day plant populations are exchanging seed and pollen. An approach is proposed here to minimize the effect of genotyping problems on contemporary migration rate estimates, which should help avoiding erroneous migration inference, monitoring and management, especially when dealing with low migration rates and their associated uncertainty.

Dispersal ecologists can take the most of their dispersal distance records by applying statistics of extremes to infer the probability of occurrence of extremely rare, but crucial, long distance dispersal events that reach locations well beyond focal populations.

Long-distance dispersal (LDD) events are extremely difficult to characterize empirically. Strict-sense LDD events involve movement both outside the stand geographic limits and outside the genetic neighbourhood area of individuals. Combinations of propagule movements within/outside these two spatial reference frames result in four distinct modes of LDD, here illustrated for four functional groups of frugivores dispersing seeds of Prunus mahaleb.

We found pervasive empirical evidence for the overriding role of humans in the large-scale spread of invasive plants from multiple taxa. The observed spread patterns differ significantly from those portrayed in the literature, emphasizing the need to develop new frameworks to explore large-scale spread in general and invasive spread in particular. With public data sets of invasive species observations becoming increasingly more available, the time is ripe to go beyond exploration of species traits and habitat suitability and to examine the actual patterns and the mechanisms of large-scale invasive spread, even at a scale of thousands of kilometres over land.

The traditional approach to plant energy budgets is described by energy transfer efficiencies as presented in ecology textbooks in the context of ecosystem energetics. From the standpoint of gross reproductive economy, respiration, evapotranspiration, and consumed or residual biomass (litter) represent wasted energy, because it is not present in an individual's offspring. A demographic model of plant energetics accommodates energy-demanding processes that may lead to greater fitness through enhanced individual survival and fecundity in addition to growth.

Our results reveal a context-dependent interaction between fire and elephants as disturbance agents in savanna: the influence of fire on woody plants was sensitive to the abundance of elephants and diminished with increased plant productivity. In contrast, elephants were capable of shifting landscapes from relatively dense woodland to open savanna and exerted strong impacts irrespective of site conditions and plant productivity.

Editor's Choice

This study evaluates how 50+ years of herbivore exclusion have impacted ecosystem function in an Alaskan Arctic tundra region. Results suggest (i) the measured response of herbivory may be dependent on the duration of experimental observation, and (ii) if negative trends in lemming populations persist in arctic tundra as reported elsewhere, the historically strong tundra carbon sink capacity may be severely reduced. Upscaled C-CO_2eq for lemming absence (left) and presence (right), across a 421 km² region of the Barrow Peninsula. Red colours represent carbon loss, and green colours represent carbon uptake.

Leaf-cutter ants may largely limit early seedling establishment of woody species by reducing seed availability and seedling survival with differential species-specific effects. Atta ants may therefore be acting as an ecological filter, which coupled with potential selectivity in foraging on reproductive life-history stages, may influence the relative abundance of different species and hence the structure and composition of Cerrado vegetation.

Our results suggest that plant communities at higher elevation are composed of species that are generally more palatable for insect herbivores. Shift in plant palatability with elevation may thus be the outcome of a relaxation of the in situ herbivore pressure and changes in abiotic conditions.

Many drylands are projected to become more water-limited with climate change. In this study, we examined the drought resistance of three dominant plants to an ongoing experimental drought in the Colorado Plateau. Our results suggest that a future with less precipitation and higher temperatures may increase the dominance of shrubs in this region as grasses succumb to chronic water stress.

Warming and drought will occur simultaneously in the future in many regions, but little is known about the responses of trees to reduced precipitation and increased temperature acting at once. In a semi-arid woodland, we assessed the responses in physiological and morphological foliar traits of pinon pine and juniper in response to three years of a 45% reduction in precipitation, a 4.8 °C increase in air temperature and their simultaneous effects. Our results indicate that in ecosystems where tree functioning is already highly limited by soil water availability, atmospheric warming as anticipated with climate change may have less impact on foliar trait responses than previously thought.

Early inundation or drought experience may be harmful immediately, but can be beneficial for the later growth of plants. The ability of species to utilize early hydrological experiences was associated with the water range of their habitats and whether the species is invasive or native. The ability to modulate future plastic responses may be as important as short-term plasticity in adapting to temporal environmental heterogeneity. Such ‘metaplasticity’ can optimize current performance, while avoiding the potential costs of maintaining a high degree of plasticity throughout life.

In pollination mutualisms, primary and secondary nectar robbers provide a clear example of a multiple-exploiter system. We tested the effects of primary and secondary robbing on the female fitness of Ipomopsis aggregata. Additional exploitation by secondary nectar robbers significantly reduced reproductive output. Our findings provide evidence that interacting with multiple exploiters can lead to increased negative effects for mutualists.

We assessed the effects of pollination intensity on both quantity and quality of progeny in a wind-pollinated herb. We found a reduction in pollen load and subsequent seed production with increasing distance to males, but only small effects on the performance of offspring. Pollen-limited females produced fewer but larger seeds, and offspring that subsequently performed better with gender-dependent effects.

With three decomposition experiments, Chen et al. demonstrate that root decomposition decreases with increasing plant diversity and that changes in both root substrate quality and soil environmental conditions contribute to this negative effect of plant divers. This study promotes the mechanistic understanding of increased soil carbon accumulation in more diverse grassland plant communities.

Conservation of AMF communities to maintain a full complement of ecosystem functions requires the presence of diverse families and not simply diverse species within a family. This finding may be of key importance for the function of ecosystems under various environmental perturbations to which AMF families may respond differently.

We found that mountain ash (Eucalyptus regnans) strongly enhanced microbial decomposition and nitrogen mineralization to facilitate its growth after a wildfire. At the ecosystem scale, the synergistic effects of plant growth and soil N mineralization need to be carefully assessed against costs to soil C for forests regenerating after disturbance.

Our results provide evidence for increasing positive diversity effects on fine root productivity with stand development in heterogeneous natural forests. Moreover, our results indicate that the increased positive diversity effects with stand development was the result of multiple mechanisms, including higher horizontal soil volume filling, a thicker forest floor layer for rooting, a higher magnitude of complementarity in nutrient-poor deep soil layers and stronger nutrient foraging towards soil layers with high nutrient concentrations in older than younger stands.

This experiment that altered the natural phenology of spring ephemeral herb species in temperate deciduous forest demonstrates that cold temperatures in early spring and canopy shade in late spring lower the survival and reproduction of most species. These constraints explain their ephemeral phenology. The results indicate their potential vulnerability to shifting patterns of frost and shade with climate change.

We studied the evolution of the invasive plant Impatiens glandulifera across its invasion chronosequence. Our results suggest that while introduced populations initially evolve decreased herbivore resistance, herbivore recolonization over time can select for its recovery to pre-introduction levels. Photograph credit: Lara Braun.

Changes in mean pairwise distance (MPD) and standardized mean nearest taxon distance (sesMNTD) suggest that extirpation of species at edges or in highly fragmented landscapes increases the dominance of species within a subset of clades (phylogenetic clustering), likely those adapted to disturbance. Smaller patch sizes are phylogenetically diverse and overdispersed, probably due to an invasion of edge-adapted species. Conservation must enhance patch area and connectivity via forest restoration; pivotally, even small forest patches are important reservoirs of phylogenetic diversity in the highly threatened Brazilian Atlantic forest.

Our study reveals how the combination of abiotic stress and biotic interactions shapes the functional diversity of alpine grasslands at different spatial scales, and highlights the importance of phenotype variation between individuals for community assembly processes at fine spatial scale. Our results suggest that studies analysing trait-based assembly rules but ignoring ITV and focusing on a single spatial scale are likely to miss essential features of community diversity patterns.