Throughout May, we will be featuring all the articles that were shortlisted for the Harper Prize 2020. The Harper Prize is an annual award for the best early career research paper published in Journal of Ecology.

To start off this blog series, we hear from Michał Bogdziewicz! Michał’s article, “Do benefits of seed dispersal and caching by scatterhoarders outweigh the costs of predation? An example with oaks and yellow‐necked mice” was one of the eight papers shortlisted for this year’s award. Michał has also been an Associate Editor for our journal for the last 18 months. Michał is an exceptional member of our Editorial Board, with an expertise for handling seed ecology manuscripts.

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Shorlisted Article

In this nominated paper, we used a combination of field data and mathematical models and showed that scatter hoarding animals (in our case, small rodents) are not always the best friends of plants (here, two oak species from Central Europe). Generally, the notion that seed-dispersing rodents are mutualists for their plant partners appears to be often taken for granted in the literature. However, the costs imposed by rodents on plants (seed predation) are rarely gauged vs. the benefits (dispersal and improved recruitment). In an attempt to solve that, we conducted a seed sowing experiment to examine if the benefits of seed transportation and seed burial are large enough to compensate for predation.

Contrary to the established view, we found that the rather small burial benefits and transportation benefits were not enough to outweigh costs. At the time of our work, the interaction was antagonistic. We demonstrated that certain common assumptions — that caching by rodents invariably benefits plant recruitment; that improved seedling establishment after seed burial is sufficient to make plant-scatterhoarder interactions mutualistic; that transportation away from maternal plants is highly beneficial — do not always hold and should be tested rather than taken for granted. This result is controversial. Before the work was published, the frequent pushback we were getting was coming from people who disliked our conclusions, rather than our methods.

We also had very fruitful discussion about our results and what they mean for the ecology of conditional mutualism with Moore and Dittel, where we argued that evaluating costs and benefits of the plant-scatter hoarding interactions can be a move forward for the field (Zwolak, Bogdziewicz & Crone, 2020, Journal of Ecology).

Figure 1. Classification of oak–granivore interactions based on the probability of caching and not retrieving seeds, and the ratio of seedling emergence from the ground to emergence from caches. The net effect of granivores is beneficial at any point above the dotted grey line and antagonistic at any point below it. The ‘far’ and ‘near’ categories indicate the establishment ratio calculated based on the seedling establishment rate estimated at distances of 0 m (near) and 25 m (far). For Quercus petraea, the ratio components did not differ with the distance from the seed source tree. The values on y‐axis (proportion of acorns cached and not retrieved) are derived from another study conducted in the same forest (Bogdziewicz et al., 2019, Journal of Ecology).

Current Research

I currently shifted most of my attention to study masting, i.e. the ecology and evolution of synchronised interannual variation in seed production in perennial plants. A lot is going on in that field currently, as we are learning more and more about proximate mechanisms of masting (Bogdziewicz et al. 2020a & 2020b, Ecology Letters), and how masting is responding to climate change (Bogdziewicz et al. 2020c, Nature Plants, 2020d, Current Biology & 2021, Global Change Biology).

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We announced the winners for the Harper Prize 2020 last week, find out more on the blog.

You can also read all 8 shortlisted papers in our new Harper Prize 2020 Virtual Issue. These articles are free to read for a limited time!