Temperature and nutrient availability alter consequences of phenological shifts in predatory-prey communities
Rudolf, Volker (2022), Temperature and nutrient availability alter consequences of phenological shifts in predatory-prey communities, Dryad, Dataset, https://doi.org/10.5061/dryad.v9s4mw6x8
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.
The data includes two experiments conducted in mesocosms in 2013 and 2015. The first experiment was conducted with dragonfly predators Anax junis and tadpole prey Rana sphenocephala, and the second with salamander Ambystoma talpoideum and tadpole from Rana clamitans. The experiments had the same experimental design, manipulating prey arrival (0 delay, 10 days or 20 days after predator addition), crossed fully factorially with 2 warming (ambient vs +4.5C) and nutrient additions (ambient vs added) resulting in 12 treatments. Experiments lasted 189 and 100 days respectively and were monitored daily. Collected data includes: predator and prey development time (from addition to experiment to metamorphosis) and mortality (number of survivors), salamander mass and prey mass at metamorphosis, periphyton abundance (measures as clorophyll a), temperature data from temperature loggers (set at 30 minute intervals), predator sizes at each prey addition, and prey size after ~35-38 days.
The corresponding R code is also provide as markdown document.
All the information about data is given in corresponding Markdown document. Note that the data includes all raw data, and has not been "cleaned" yet for outlier etc. This was done in the R code and indicated in the markdown files (e.g. removal of clear data entry errors in tadpole mass).
Date is listed in DataMetafile_ReadMe.docx
National Science Foundation, Award: DEB-1256860
National Science Foundation, Award: DEB-1655626