Biology subjects

Rudolf, V. H. W.

Publications and source records attributed to Rudolf, V. H. W..

6 recordsLinked to original sources

bioRxiv2023

Time-dependent Interaction Modification Generated from Plant-soil Feedback

Pairwise interactions between species can be modified by other community members, leading to emergent dynamics contingent on community composition. Despite the prevalence of such higher-order interactions, little is known about how they are linked to the timing and order of species arrival. We generate population dynamics from a mechanistic plant-soil feedback model, then apply a general theoretical framework to show that the modification of a pairwise interaction by a third plant depends on its germination phenology. These time-dependent interaction modifications emerge from concurrent changes in plant and microbe populations and are strengthened by higher overlap between plants associated microbiomes. The interaction between this overlap and the specificity of microbiomes further determines plant coexistence. Our framework is widely applicable to mechanisms in other systems from which similar time-dependent interaction modifications can emerge, highlighting the need to integrate temporal shifts of species interactions to predict the emergent dynamics of natural communities.

ecology↗

bioRxiv2023

Predation and competition drive trait diversity across space and time

Competition should play a key role in shaping community assembly and thereby local and regional biodiversity patterns. However, identifying its relative importance and effects in natural communities is challenging because theory suggests that competition can lead to different and even opposing patterns depending on the underlying mechanisms. Here, weve taken a different approach: rather than attempting to indirectly infer competition from diversity patterns, we compared trait diversity patterns in odonate (dragonfly and damselfly) communities across different spatial and temporal scales along a natural competition-predation gradient. At the local scale (within a community), we found that trait diversity increased with the size of top predators (from invertebrates to fish). This relationship is consistent with differences in taxonomic diversity, suggesting that competition reduces local trait diversity through competitive exclusion. Spatial (across communities) and temporal (within communities over time) trait variation peaked in communities with intermediated predators indicating that both high levels of competition or predation select for trait-convergence of communities. This indicates that competition acts as a deterministic force that reduces trait diversity at the local, regional, and temporal scales, which contrasts with patterns at the taxonomic level. Overall, results from this natural experiment reveal how competition and predation interact to shape biodiversity patterns in natural communities across spatial and temporal scales and provide new insights into the underlying mechanisms. Open Research statementData and/or code are provided as private-for-peer review via the following link: [Link to external storage location] and will be made publicly available with publication

ecology↗

bioRxiv2022

Bridging Theory and Experiments of Priority Effects

Priority effects play a key role in structuring natural communities, but considerable confusion remains about how they affect different ecological systems. Synthesizing previous studies, we show that this confusion arises because the mechanisms driving priority and the temporal scale at which they operate differ among studies, leading to divergent outcomes in species interactions and biodiversity patterns. We suggest grouping priority effects into two functional categories based on their mechanisms: "frequency-dependent" priority effects that arise from positive frequency dependence, and "trait-dependent" priority effects that arise from time-dependent changes in interacting traits. Through easy quantification of these categories from experiments, we can construct community models representing diverse biological mechanisms and interactions with priority effects, therefore better predicting their consequences across ecosystems.

ecology↗

bioRxiv2022

Priority effects determine how dispersal affects biodiversity in seasonal metacommunities

The arrival order of species frequently determines the outcome of their interactions. This phenomenon, called the priority effect, is ubiquitous in nature and determines local community structure, but we know surprisingly little about how it influences biodiversity across different spatial scales. Here, we use a seasonal metacommunity model to show that biodiversity patterns and the homogenizing effect of high dispersal depend on the specific mechanisms underlying priority effects. When priority effects are only driven by positive frequency dependence, dispersal-diversity relationships are sensitive to initial conditions but generally show a hump-shaped relationship: biodiversity declines when dispersal rates become high and allow the dominant competitor to exclude other species across patches. When spatiotemporal variation in phenological differences alters species interaction strengths (trait-dependent priority effects), local, regional, and temporal diversity are surprisingly insensitive to variation in dispersal, regardless of the initial numeric advantage. Thus, trait-dependent priority effects can strongly reduce the effect of dispersal on biodiversity, preventing the homogenization of metacommunities. Our results suggest an alternative mechanism that maintains local and regional diversity without environmental heterogeneity, highlighting that accounting for the mechanisms underlying priority effects is fundamental to understanding patterns of biodiversity.

ecology↗

bioRxiv2021

TEMPERATURE AND NUTRIENT CONDITIONS MODIFY THE EFFECTS OF PHENOLOGICAL SHIFTS IN PREDATOR-PREY COMMUNITIES

While there is mounting evidence indicating that the relative timing of predator and prey phenologies shapes the outcome of trophic interactions, we still lack a comprehensive understanding of how important the environmental context (e.g. abiotic conditions) is for shaping this relationship. Environmental conditions not only frequently drive shifts in phenologies, but they can also affect the very same processes that mediate the effects of phenological shifts on species interactions. Thus, identifying how environmental conditions shape the effects of phenological shifts is key to predict community dynamics across a heterogenous landscape and how they will change with ongoing climate change in the future. Here I tested how environmental conditions shape effects of phenological shifts by experimentally manipulating temperature, nutrient availability, and relative phenologies in two predator-prey freshwater systems (mole salamander-bronze frog vs dragonfly larvae-leopard frog). This allowed me to (1) isolate the effect of phenological shifts and different environmental conditions, (2) determine how they interact, and (3) how consistent these patterns are across different species and environments. I found that delaying prey arrival dramatically increased predation rates, but these effects were contingent on environmental conditions and predator system. While both nutrient addition and warming significantly enhanced the effect of arrival time, their effect was qualitatively different: Nutrient addition enhanced the positive effect of early arrival while warming enhanced the negative effect of arriving late. Predator responses varied qualitatively across predator-prey systems. Only in the system with strong gape-limitation were predators (salamanders) significantly affected by prey arrival time and this effect varied with environmental context. Correlations between predator and prey demographic rates suggest that this was driven by shifts in initial predator-prey size ratios and a positive feedback between size-specific predation rates and predator growth rates. These results highlight the importance of accounting for temporal and spatial correlation of local environmental conditions and gape-limitation in predator-prey systems when predicting the effects of phenological shifts and climate change on predator-prey systems.

ecology↗

bioRxiv2020

Priority effects and season length shape long-term competition dynamics

The relative arrival time of species can affect their interactions and thus determine which species persist in a community. Although this phenomenon, called priority effect, is widespread in natural communities, it is unclear how it depends on the length of growing season. Using a seasonal stage-structured model, we show that differences in stages of interacting species could generate priority effects by altering the strength of stabilizing and equalizing coexistence mechanisms, changing outcomes between exclusion, coexistence, and positive frequency dependence. However, these priority effects are strongest in systems with just one or a few generations per season and diminish in systems where many overlapping generations per season dilute the importance of stage-specific interactions. Our model reveals a novel link between the number of generations in a season and the consequences of priority effects, suggesting that consequences of phenological shifts driven by climate change should depend on specific life histories of organisms.

ecology↗