Seasonal Changes in Functional Trait Distribution in a Temperate Forest Community

Background/Question/Methods

In temperate forests, seasonality shifts may be changing due to climate change. As a result of this potential change, it is important to understand the relationship between functional traits (e.g., trophic level) in a community and how those traits can best be utilized for conservation and management strategies. Shifts in seasonal environmental variables will likely impact the activity level and interactions between wildlife species within these communities and could have broader implications for ecosystem functioning. Activity levels of predators and herbivores has the potential to influence one another, in that potential prey species may be more or less available based on different environmental regimes. We chose to examine two temperate forests in Massachusetts over two years (2019 and 2020), from early to late fall using camera traps. We categorized our species into herbivores or predators and developed a daily activity metric, binned by weeks and corrected for camera prevalence. We took the weekly sum of observations in a site, divided by the cameras in a site, and the divided by seven to develop a daily activity per week, corrected for sampling effort. We then investigated activity patterns within and between herbivores and predators as the season progressed.

Results/Conclusions

Data were collected from 24 camera traps in two sites. We recorded a total of 6,436 photos, which were categorized into 36 different species (18 predators and 18 herbivores). We found that activity differed by year and that predator activity was offset from herbivore activity. In 2019 herbivores were most prevalent at week 5 (29 Sept – 5 Oct) 3.2 +/- 1.1 daily observations/camera and in 2020 herbivores were most prevalent at week 8 (20-26 Oct) 4.7 +/- 3.1. In 2019, predators were offset from herbivores by a week, with most activity in week 4 (22-28 Sept) 0.56 +/- 0.21 daily observations/camera. In 2020, the mismatch between predator and herbivore activity was even more pronounced, with predators most active in week 3 (15-21 Sept) 0.84+/- 0.39 daily observations/camera, which is 5 weeks offset from 2020 peak herbivore activity. Potential changes in climatic patterns can have far-reaching consequences for wildlife, with impacts already reported for most taxonomic groups. The response of species to long-term environmental changes such as climate change will be determined by their ability to adapt (or not). One possible response to climate change is a phenological response, leading to changes of plant and animal interactions.