ARS | Publication request: Seed-caching by heteromyid rodents enhances seedling survival of a desert grass, Indian ricegrass (Achnatherum hymenoides)

Submitted to: Ecological Society of America (ESA)
Publication Type: Abstract Only
Publication Acceptance Date: June 7, 2012
Publication Date: August 10, 2012
Citation: Dimitri, L.A., Longland, W.S. 2012. Seed-caching by heteromyid rodents enhances seedling survival of a desert grass, Indian ricegrass (Achnatherum hymenoides) [abstract]. Ecological Society of America. p. 182.

Technical Abstract: Seeds of many plant species germinate and establish aggregated clusters of seedlings from shallowly buried seed caches (i.e., scatterhoards) made by granivorous animals. Scatterhoarding by desert heteromyid rodents facilitates the vast majority of seedling recruitment in Indian ricegrass (Achnatherum hymenoides), but any benefits resulting from rodent seed dispersal depend on subsequent survival of clustered seedlings. We conducted observational studies at two western Nevada study sites in which we compared survival of clustered Indian ricegrass seedlings emerging from rodent caches to single seedlings over a 1-year period after seeding emergence. Clumped seedlings generally had higher survival than single seedlings in both studies. We followed this up with a field experiment in which we planted Indian ricegrass seedlings inside fenced plots either singly or in clumps of 25 or 35 seedlings and compared survival through their first winter. In the experiment, clumped seedlings transplanted to both sites had higher survival than single seedlings, and clumps of 25 seedlings generally had the highest survival. These results provide further evidence of a mutualism involving heteromyid rodents and Indian ricegrass. Benefits to Indian ricegrass can extend beyond seed dispersal and seedling establishment and into the longer-term survival of the plant.