Grazers and granivores have the potential to affect seed banks. Several studies have examined the impact of these herbivores on the aboveground vegetation, but few have looked at how they influence the seed bank. I asked whether both grazers and granivores alter the seed bank at the Sevilleta National Wildlife Refuge. Long-term experimental plots were installed in 1996 to exclude grazers and granivores from a grassland and shrubland. Soil samples were collected from these plots and seeds were germinated in a greenhouse. The grassland had significantly more species in its seed bank than the shrubland. Also, the seed bank composition differed significantly between the two sites. However, the number of species in the seed bank did not vary among herbivore treatments nor did total seed numbers vary among treatments at the grassland. At the shrubland, in contrast, plots that excluded both herbivores had fewer total seeds than control plots and plots where only grazers were excluded. Therefore, although herbivores play some role in the shrubland, herbivores do not reduce seed numbers at either site. Thus, seed bank size is not controlled by the consumption of seeds from these herbivores, but by some other factor (e.g. disturbance or abiotic events).
Knowledge Network for Biocomplexity (KNB) Identifier
Data Policies: This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement of the Sevilleta LTER. Datasets must be cited as in the example provided. A copy of any publications using these data must be supplied to the Sevilleta LTER Information Manager. By downloading any data you implicitly acknowledge the LTER Data Policy (http://www.lternet.edu/data/netpolicy.html).
SEV LTER, Department of Biology, University of New Mexico, Albuquerque, NM , 87131
2004-03-01 - 2004-10-01
Location: Five Points Black Grama is on the transition between Chihuahuan Desert Scrub and Desert Grassland habitat. The site is subject to intensive research activity, including assessments of net primary productivity, phenology, and pollinator diversity, amongst other projects. It is the site of the unburned black grama (GU) component of the Burn NPP study. On August 4, 2009, a lightning-initiated fire began on the Sevilleta National Wildlife Refuge. By August 5, 2009, the fire had reached the Five Points Black Grama site. Portions of this site were burned, but not the entirety. See individual projects for further information on the effects of the burn. Vegetation: The Five Points Black Grama site is ecotonal in nature, bordering Chihuahuan Desert Scrub at its southern extent and Plains-Mesa Grassland at its northern, more mesic boundary. Characteristically, the dominant grass is black grama (Bouteloua eriopoda).
Koontz, Terri (2011): Effects of Herbivores on Seed Banks of Grass and Shrublands at the Sevilleta National Wildlife Refuge, New Mexico (2004). Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/f907a28c8f3e52a7514c197925d0039a