|Hollander, Jennifer -|
|Vander Wall, Stephen -|
Submitted to: Western North American Naturalist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2012
Publication Date: November 19, 2012
Citation: Hollander, J.L., Vander Wall, S.B., Longland, W.S. 2012. Olfactory detection of caches containing wildland versus cultivated seeds by granivorous rodents. Western North American Naturalist. 72:339-347. Interpretive Summary: Not all seeds harvested by seed-eating animals are eaten; many are stored for future use. Many plants are known to utilize rodents to disperse seeds to superficially buried caches, which provide ideal germination conditions. Rodents locate buried seeds using smells, so seeds of plant species that are commonly cached may have adapted to this type of dispersal by loss of conspicuous odors. We tested abilities of rodents to locate buried seed caches for both native seeds that are adapted to rodent seed dispersal and for introduced and commercial seeds that did not evolve together with desert rodents, and thus should not have developed such adaptations. Artificial seed caches were buried 1.5 cm deep using seeds of 3 wildland plant species and 3 commercial seed types. Rodents were able to locate cultivated seeds much more rapidly than seeds of wildland plant species, especially when the soil was dry. This stimulates the possibility of mixing commercial “diversionary” seeds with native seeds that managers wish to establish when reseeding damaged rangelands. The more detectable diversionary seeds should reduce numbers of less conspicuous native seeds consumed by rodents.
Technical Abstract: We conducted a study to examine the ability of rodents to detect caches made with wildland (native and non-native) and cultivated seeds at three locations in western Nevada with different vegetation types and rodent community structures. We established artificial caches containing either one of two species of wildland seeds or cultivated seeds. Five seed species were tested at each site. Under dry conditions, rodents found caches containing cultivated seeds much more rapidly than caches containing wildland seeds. Wet conditions resulted in a similar order of detectability; however, all species of seeds were located much faster than under dry conditions. Natural selection has likely acted on the wildland seeds to reduce their olfactory signal, and potentially reduce predation upon those seeds.