I have a long-standing interest in the effects of weather and climate on animal population dynamics and ecological communities.
Brad Hawkins and I (Hawkins and Holyoak 1998). showed how widespread droughts can cause simultaneous crashes in insect populations. A recent systematic review (Wan et al. 2023) examined the effects on animal population abundances of large-scale climate drivers such such as El Niño Southern Oscillation (ENSO) cycles. The study shows how such effects vary among major animal groups and geographic regions.
Over ten years of NSF-funded research with Rick Karban at UC-Davis explored the effects of weather on a web of species interactions and spatial dynamics associated with a focal herbivore, Ranchman's Tiger Moth (wooly bears). The caterpillars regularly go extinct from dry "sink" habitats during droughts whereas populations in wetter marsh "source" habitats persist (Karban et al. 2012; Grof-Tisza et a. 2019). Interactions with predatory ants were mediated by flooding (Karban et al. 2017). Time series analyses of the long-term population dynamics of the caterpillars led by Adam Pepi showed a regime shift in the cyclicity of population fluctuations that were coincident with shifts in precipitation (Pepi et al. 2021).
![Wooly bear caterpillar at Bodega, photo Adam Pepi](/sites/g/files/dgvnsk13991/files/media/images/wooly_bear_A_Pepi.jpg)
Wooly bear caterpillar on bush lupine. Photo Adami Pepi.