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1. Quantifying the effects of intraspecific variation on predator feeding rates through nonlinear averaging

   https://doi.org/10.1111/1365-2435.13802  

   Coblentz, Kyle E. ; Merhoff, Stephanie ; Novak, Mark ( June 2021 , Functional Ecology)

   Theory suggests that intraspecific trait variation will alter species interaction strengths through nonlinear averaging when interaction strengths are nonlinear functions of individuals' traits. This effect is expected to be widespread, yet what factors mediate its magnitude in nature and hence its potential effects on ecosystems and communities are unclear.

   We sought to quantify how nonlinear predator functional responses, variation in prey densities and counteracting variation in attack rates and handling times among predator individuals of similar body size alter their population‐level feeding rates through nonlinear averaging in a natural system, and to determine the processes influencing the net magnitude of this effect.

   We used a field caging experiment in the rocky intertidal of Oregon, USA to quantify attack‐rate variation and feeding rates of the whelkNucella ostrinaon its barnacle and mussel prey. We also used empirically parameterized simulations to examine the effects of handling‐time variation among individuals on population‐level feeding rates.

   Within cages, individual attack‐rate variation reduced population‐level whelk feeding rates. However, the magnitude of this reduction differed among prey species and cages depending on cage‐specific magnitudes of attack‐rate variation and functional‐response nonlinearity. The inferred effects of handling‐time variation among individuals were of smaller magnitude than those of attack‐rate variation, yet counteracted them to cause a net weakening of the effect of individual attack‐rate variation on population‐level feeding rates. Across cages, attack‐rate and prey‐density variation had non‐additive effects that produced greater feeding‐rate reductions at the experiment scale relative to the cage scale.

   Our results indicate that the effects of trait variation via nonlinear averaging depend critically on the features of systems that determine the magnitudes of nonlinearities and trait variation. Because of counteracting trait variation, nonlinear‐averaging effects may be quite complex, involving both the variances and covariances of all traits and environmental variables influencing the ecological process of interest.

   A freePlain Language Summarycan be found within the Supporting Information of this article.

    

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2. Analysing eco‐evolutionary dynamics—The challenging complexity of the real world

   https://doi.org/10.1111/1365-2435.13261  

   De Meester, Luc ; Brans, Kristien I. ; Govaert, Lynn ; Souffreau, Caroline ; Mukherjee, Shinjini ; Vanvelk, Héléne ; Korzeniowski, Konrad ; Kilsdonk, Laurens ; Decaestecker, Ellen ; Stoks, Robby ; et al ( January 2019 , Functional Ecology)

   The field of eco‐evolutionary dynamics is developing rapidly, with a growing number of well‐designed experiments quantifying the impact of evolution on ecological processes and patterns, ranging from population demography to community composition and ecosystem functioning. The key challenge remains to transfer the insights of these proof‐of‐principle experiments to natural settings, where multiple species interact and the dynamics are far more complex than those studied in most experiments.

   Here, we discuss potential pitfalls of building a framework on eco‐evolutionary dynamics that is based on data on single species studied in isolation from interspecific interactions, which can lead to both under‐ and overestimation of the impact of evolution on ecological processes. Underestimation of evolution‐driven ecological changes could occur in a single‐species approach when the focal species is involved in co‐evolutionary dynamics, whereas overestimation might occur due to increased rates of evolution following ecological release of the focal species.

   In order to develop a multi‐species perspective on eco‐evolutionary dynamics, we discuss the need for a broad‐sense definition of “eco‐evolutionary feedbacks” that includes any reciprocal interaction between ecological and evolutionary processes, next to a narrow‐sense definition that refers to interactions that directly feed back on the interactor that evolves.

   We discuss the challenges and opportunities of using more natural settings in eco‐evolutionary studies by gradually adding complexity: (a) multiple interacting species within a guild, (b) food web interactions and (c) evolving metacommunities in multiple habitat patches in a landscape. A literature survey indicated that only a few studies on microbial systems so far developed a truly multi‐species approach in their analysis of eco‐evolutionary dynamics, and mostly so in artificially constructed communities.

   Finally, we provide a road map of methods to study eco‐evolutionary dynamics in more natural settings. Eco‐evolutionary studies involving multiple species are necessarily demanding and might require intensive collaboration among research teams, but are highly needed.

   Aplain language summaryis available for this article.

    

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3. BoomBox: An Automated Behavioural Response (ABR) camera trap module for wildlife playback experiments

   https://doi.org/10.1111/2041-210X.13789  

   Palmer, Meredith S. ; Wang, Chris ; Plucinski, Jacinta ; Pringle, Robert M. ( January 2022 , Methods in Ecology and Evolution)

   Camera traps (CTs) are a valuable tool in ecological research, amassing large quantities of information on the behaviour of diverse wildlife communities. CTs are predominantly used as passive data loggers to gather observational data for correlational analyses. Integrating CTs into experimental studies, however, can enable rigorous testing of key hypotheses in animal behaviour and conservation biology that are otherwise difficult or impossible to evaluate.

   We developed the 'BoomBox', an open‐source Arduino‐compatible board that attaches to commercially available CTs to form an Automated Behavioural Response (ABR) system. The modular unit connects directly to the CT’s passive infrared (PIR) motion sensor, playing audio files over external speakers when the sensor is triggered. This creates a remote playback system that captures animal responses to specific cues, combining the benefits of camera trapping (e.g. continuous monitoring in remote locations, lack of human observers, large data volume) with the power of experimental manipulations (e.g. controlled perturbations for strong mechanistic inference).

   Our system builds on previous ABR designs to provide a cheap (~100USD) and customizable field tool. We provide a practical guide detailing how to build and operate the BoomBox ABR system with suggestions for potential experimental designs that address a variety of questions in wildlife ecology. As proof‐of‐concept, we successfully field tested the BoomBox in two distinct field settings to study species interactions (predator–prey and predator–predator) and wildlife responses to conservation interventions.

   This new tool allows researchers to conduct a unique suite of manipulative experiments on free‐living species in complex environments, enhancing the ability to identify mechanistic drivers of species' behaviours and interactions in natural systems.

    

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4. The recovery of plant community composition following passive restoration across spatial scales

   https://doi.org/10.1111/1365-2745.14063  

   Ladouceur, Emma ; Isbell, Forest ; Clark, Adam T. ; Harpole, W. Stanley ; Reich, Peter B. ; Tilman, G. David ; Chase, Jonathan M. ( February 2023 , Journal of Ecology)

   Human impacts have led to dramatic biodiversity change which can be highly scale‐dependent across space and time. A primary means to manage these changes is via passive (here, the removal of disturbance) or active (management interventions) ecological restoration. The recovery of biodiversity, following the removal of disturbance, is often incomplete relative to some kind of reference target. The magnitude of recovery of ecological systems following disturbance depends on the landscape matrix and many contingent factors. Inferences about recovery after disturbance and biodiversity change depend on the temporal and spatial scales at which biodiversity is measured.

   We measured the recovery of biodiversity and species composition over 33 years in 17 temperate grasslands abandoned after agriculture at different points in time, collectively forming a chronosequence since abandonment from 1 to 80 years. We compare these abandoned sites with known agricultural land‐use histories to never‐disturbed sites as relative benchmarks. We specifically measured aspects of diversity at the local plot‐scale (α‐scale, 0.5 m²) and site‐scale (γ‐scale, 10 m²), as well as the within‐site heterogeneity (β‐diversity) and among‐site variation in species composition (turnover and nestedness).

   At our α‐scale, sites recovering after agricultural abandonment only had 70% of the plant species richness (and ~30% of the evenness), compared to never‐ploughed sites. Within‐site β‐diversity recovered following agricultural abandonment to around 90% after 80 years. This effect, however, was not enough to lead to recovery at our γ‐scale. Richness in recovering sites was ~65% of that in remnant never‐ploughed sites. The presence of species characteristic of the never‐disturbed sites increased in the recovering sites through time. Forb and legume cover declines in years since abandonment, relative to graminoid cover across sites.

   Synthesis.We found that, during the 80 years after agricultural abandonment, old fields did not recover to the level of biodiversity in remnant never‐ploughed sites at any scale. β‐diversity recovered more than α‐scale or γ‐scale. Plant species composition recovered, but not completely, over time, and some species groups increased their cover more than others. Patterns of ecological recovery in degraded ecosystems across space and long time‐scales can inform targeted active restoration interventions and perhaps, lead to better outcomes.

    

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5. Streetlights positively affect the presence of an invasive grass species

   https://doi.org/10.1002/ece3.7835  

   Murphy, Shannon M. ; Vyas, Dhaval K. ; Hoffman, Jennifer L. ; Jenck, Clara S. ; Washburn, Brooke A. ; Hunnicutt, Kelsie E. ; Davidson, Angie ; Andersen, Jasmine M. ; Bennet, Rachel K. ; Gifford, Amarin ; et al ( July 2021 , Ecology and Evolution)

   null (Ed.)

   Anthropogenic disturbances associated with urban ecosystems can create favorable conditions for populations of some invasive plant species. Light pollution is one of these disturbances, but how it affects the growth and establishment of invasive plant populations is unknown. Cheatgrass (Bromus tectorum) is a problematic invasive species where it has displaced native grassland communities in the United States, but to our knowledge, there have been no studies of the ecological factors that affect cheatgrass presence in urban ecosystems. We conducted field surveys in urban alleys in Denver, Colorado, to compare the presence of cheatgrass at sites with and without artificial light at night (hereafter artificial light) from streetlights. These streetlights are mounted on utility poles, which cause ground disturbance when installed in alleys; we were able to test the independent effect of poles on cheatgrass establishment because not all poles have streetlights on them. We found that cheatgrass was positively associated with the presence of streetlights and to a lesser extent poles. In addition to cheatgrass, we also found that other plants were positively associated with the presence of both poles and streetlights. Our results suggest that artificial light may benefit the occurrence of cheatgrass and other plant species in urban settings. While invasive populations of cheatgrass in wild habitats attract the most attention from managers, we suggest more consideration for this grass in urban environments where its growth and establishment benefit from anthropogenic changes. 

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