Nutritional and environmental factors influence small mammal seed selection in a northern temperate forest

Abstract

Rodents can influence the succession and assembly of plant communities by preying on and dispersing seeds. Using a seed tray experiment with three common seeds, American beech (Fagus grandifolia), red maple (Acer rubrum), and eastern hemlock (Tsuga canadensis), we assessed factors that influence seed selection and foraging time of three rodents: deer mice (Peromyscus maniculatus), white-footed mice (Peromyscus leucopus), and southern red-backed voles (Myodes gapperi). All three rodents preferred beech seeds, likely due to its large size and high lipid content. However, when beech availability was low, secondary seed selection differed by rodent species with P. maniculatus equally selecting hemlock and red maple, P. leucopus preferring hemlock, and M. gapperi preferring red maple. Red maple seeds contained high levels of phenolic compounds, which hinder digestion, and the elongated cecum of M. gapperi may allow for better processing of these compounds relative to Peromyscus. Beech seeds were nearly always removed from trays intact, suggesting rodents could be important dispersers compared to the small-seeded species, which were generally processed on trays. The influence of environmental factors on seed selection was only notable when beech seed availability was low. Beech seed availability was also the primary factor influencing foraging time on trays, with individuals increasing foraging time as beech availability decreased. Consistent with predator avoidance behaviors, denser shrub cover increased foraging time for P. maniculatus, whereas moon luminosity decreased foraging for all three species. Our findings underscore that seed quality drives seed selection but that preferences are context dependent, varying with seed availability and digestive capacity.

Seed mass and seed resources – testing the defense trade-off hypothesis in woody plants

“…An opposite significant relationship was found between non-structural carbohydrates and fiber content. Many field-based research studies indicated various effects of seed traits on removal rates, where seed quality interacted with other environmental factors (e.g., precipitation, shrub level, moonlight) to influence seed selection by rodents (Perea et al, 2011;Chiuffo et al, 2018;Moore et al, 2022). Testing 40 tree species, Blate et al (1998) found that seed predation decreased with seed size and hardness of seed coat.…”

Southern Red-backed Vole (Myodes gapperi) habitat associations in northern New England forests

“…In contrast to fungi that are available throughout the breeding season (Stephens et al 2017b), Red Maple seeds are abundantly available for a short period during early summer (but may be cached for later consumption) and fluctuate in abundance year to year (Schnurr et al 2002). In northeastern forests, southern red-backed voles have been documented to select Red Maple seeds over those of other tree species (Boone and Mortelliti 2019; Moore et al 2022) and to increase their population densities following mast seeding of Red Maple (Schnurr et al 2002). Importantly, home range size did not vary with population density of voles (Tisell et al 2019), suggesting that competition for resources among neighboring conspecifics is not driving space use.…”

“…Understanding the distribution and habitat associations of forest-dwelling small mammals may thus inform forest management decisions. This is particularly the case for forest specialists such as the Southern Red-backed Vole ( Myodes gapperi ) which play an important functional role in northern forests as a consumer of seeds (Moore et al 2022) and primary disperser of mycorrhizal fungi which forms a symbiotic relationship with trees that enhances tree growth and survival and contributes to overall forest health (Orrock and Pagels 2002; Stephens and Rowe 2020).…”

A conceptual framework linking pollen limitation and seed dispersal effectiveness

“…Some of these potential factors are the plant's and dispersers' physiological condition (e.g. Navarro 1998;Moore et al 2022), competition and predation pressure of the plant and dispersers (e.g. Houle et al 2010;Burgos et al 2022), the abundance of alternative feeding resources to dispersers (e.g.…”