OOS 53-5 - When are priority effects common and strong? A quantitative synthesis of experimental evidence across study systems

Thursday, August 10, 2023

9:00 AM – 9:15 AM PDT

Location: 255

Presenting Author(s)

CL

Chelsea J. Little

Assistant Professor
Simon Fraser University, British Columbia, Canada

Co-author(s)

FH

Fletcher W. Halliday

University of Zürich Institute for Evolutionary Biology and Environmental Studies; Oregon State University Department of Botany and Plant Pathology, United States
JS

Judith Sarneel, Associate professor

University of Umeå
tv

tamara van Steijn

PhD student
Umeå University, Department of Ecology and Environmental Sciences
Umeå, Sweden
JA

Jasmin Albert

University of Oregon
EB

Elle M. Barnes

Postdoctoral Fellow
Department of Energy Joint Genome Institute
Berkeley, California, United States
TG

Tess Grainger

University of British Columbia
PK

Paul Kardol, Professor

Swedish University of Agricultural Sciences
Umeå, Sweden
EL

Emma Ladouceur

German Centre for Integrative Biodiversity Research, Germany
VT

Vicky Temperton

Leuphana University Lüneburg, Institute of Ecology, United States
CW

Chhaya Werner

Assistant Professor
University of Southern Oregon, Environmental Science, Policy, & Sustainability
Ashland, Oregon, United States
TF

Tadashi Fukami

Stanford University, Department of Biology, United States
BD

Benjamin Delory

Leuphana University Lüneburg, Institute of Ecology, United States

The order in which species arrive in a community can influence how they interact with each other. In these historically contingent interactions, or priority effects, early-arriving species either modify or preempt ecological niches, affecting the ability of later-arriving species to fill those niches and the structure and function of the community being assembled. Ecology currently recognizes the existence of priority effects, yet our field lacks a data-based understanding, across ecological communities, of their (a) prevalence (how often priority effects are non-zero), (b) direction (when they have a positive vs. negative effects on later-arriving species), (c) magnitude (the strength of their effect on later-arriving species), and (d) impact (contribution to shaping community composition, structure, and function).

Here, we performed a systematic review and meta-analysis of experimental research on priority effects. If a species performs differently when it arrives earlier, at the same time, or later than other species, this difference indicates a priority effect. Therefore, our search targeted studies that manipulated the order of arrival of at least two species and measured the performance of those species in different arrival sequences. To address the issue that priority effects research in ecology is most often carried out in a few particular study systems, we designed a search string specifically to identify literature from other biological disciplines that fit our criteria even if the original research was not framed around priority effects.

Our search returned 3,188 studies, of which 63 studies met our inclusion criteria. From these, we extracted over 13,000 rows of data, representing the performance of 284 species in different communities, arrival sequences, and environmental conditions. Our search strategy was successful in identifying relevant experiments from beyond the field of ecology, and our data spanned from viruses, bacteria, protists, and fungi to angiosperms, nematodes, insects, crustaceans, and amphibians, and included both host-associated and free-living communities. Our meta-analysis of this dataset found that priority effects (a) are prevalent across a wide range of species and environments, (b) can be positive or negative depending on ecological context, and (c) can range from having a strong impact to a biologically-insignificant impact on late-arriving species. To our knowledge, this is the largest collection of priority effects data ever compiled, and we are continuing to glean insights from it that will improve the field’s understanding of when priority effects play an important role in shaping ecological communities.