Ant-mediated seed dispersal in a warmed world

Abstract

19Climate change affects communities both directly and indirectly via changes in interspecific 20 interactions. One such interaction that may be altered under climate change is the ant-plant seed 21 dispersal mutualism common in deciduous forests of the eastern US. As climatic warming alters 22 the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated 23 seed removal. We used an experimental temperature manipulation at two sites in the eastern US as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the 27 relationship between ant critical thermal maxima (CT max ) and the mean seed removal 28 temperature for each ant species. We found that seed removal rates did not change as a result of 29 experimental warming at either study site, nor were there any changes in species-specific rates of 30 seed dispersal. There was, however, a positive relationship between CT max and mean seed 31 removal temperature, whereby species with higher CT max removed more seeds at hotter 32 temperatures. The temperature at which seeds were removed was influenced by experimental 33 warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our 34 results suggest that while temperature may play a role in regulating seed removal by ants, ant 35 plant seed-dispersal mutualisms may be more robust to climate change than currently assumed.

Changes in canopy structure and ant assemblages affect soil ecosystem variables as a foundation species declines

“…Understory vegetation, including herbs, tree seedlings and suppressed saplings, responds rapidly to the increasing light availability attendant to hemlock decline (Catovsky andBazzaz 2000, Orwig et al 2013), and many understory species are dispersed by ants (Stuble et al 2014). Understory vegetation (plants ,1.3 m tall and ,1.0 cm diameter) was sampled annually in the canopy manipulation plots in five 1-m 2 plots spaced evenly along each of two 30-m transects (for herbs and seedlings) and within the central 30 3 30 m ''core'' area (for saplings) of each canopy removal plot (Orwig et al 2013).…”

Harvester ant seed removal in an invaded sagebrush ecosystem: Implications for restoration

“…Microclimatic conditions within sagebrush communities also drive harvester ant foraging. For example, temperatures alter daily foraging activity which can be geographically dependent (Stuble et al, 2013(Stuble et al, , 2014; however, harvester ants generally display unimodal activity in cooler months and bimodal patterns in warmer months (Crist & MacMahon, 1992;Stuble et al, 2013Stuble et al, , 2014. Vegetation structure, resource distance, and biotic factors, such as larger colonies and neighboring nests, are additional factors that can influence harvester ant foraging (Anjos et al, 2019;Gordon & Kulig, 1996;MacMahon et al, 2000).…”

Predicted impacts of climatic change on ant functional diversity and distributions in eastern North American forests

“…Wood decomposers and leaf‐litter community regulators are forecast to have large species range‐size contractions; the persistence of these functional groups, especially in the southern ecoregions, will be dependent on the response to climatic change of one or two species within their functional group. For seed dispersers (specifically their function as myrmecochores), not only does the persistence of their function depend on whether particular species keep up with changes in habitat suitability (which applies to all functional groups), but also necessitates the persistence of their associated myrmecochorous plants to track changing climates in similar ways (Stuble et al ., ).…”