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Abstract Granivores are essential for seed dispersal in seasonal ecosystems reliant on intra- and inter-annual pulses of resources for stability and maintenance of floral complexity. Successional ecosystems, such as pine barrens, also rely on disturbances to maintain diversity, leading to intrinsic resistance to urban encroachment and climate change. Despite this, oak-rodent mutualisms may be threatened by phenological decoupling due to a changing climate. Changes in temperature, relative humidity, and precipitation have cascading effects on mast-seeding plants and granivorous small-mammal populations that consume and disperse their crops in seasonal and successional environments. Here, we identified proximal phenoclimatic drivers of population abundance of the dominant small mammal in pine-oak barrens on Long Island, New York. We first estimated the population abundance of white-footed mice over a period of 4 yrs using daily and seasonal trapping efforts. We then modeled seasonal population abundance with combinations of climatic predictors hypothesized to directly influence interannual oak mast-seeding cycles and intrannual heath mast availability with indirect effects on granivore population abundance. We find that an increase in temperature between sequential springs is correlated with an increase in White-footed Mouse abundance in the following year, tracking hard mast-seeding hypotheses. Additionally, wet springs are correlated with an increase in abundance in the current year, related to spring forcing mechanisms for soft mast. In contrast, warm late springs decrease White-footed Mouse abundance due to decreased reproductive output. Discordant responses to changes in temperature and relative humidity by hard and soft mast-seeding species may present a challenge to generalist small-mammal species and their role in maintaining ecosystem resilience. Understanding these interactions can help anticipate future functional changes in oak forests.
Welles et al. (Fri,) studied this question.