Effect of domestic animals and precipitation levels on the establishment of Lehmann lovegrass (<i>Eragrostis lehmanniana Nees</i>) seedlings

TitleEffect of domestic animals and precipitation levels on the establishment of Lehmann lovegrass (Eragrostis lehmanniana Nees) seedlings
Publication TypeConference Paper
Year of Publication1996
AuthorsFlores M.A., Fredrickson E.L., Pieper, Rex D., Murray L.W.
Conference NameMexican Society for Range Management Meeting
Date PublishedAugust 20-23, 19
Conference LocationZacatecas, Mexico
Keywordsdispersal, domestic animals, Lehmann lovegrass, precipitation, seeds
Abstract

Lehmann lovegrass is an introduced grass. This grass is a very aggressive competitor and itis not preferred by livestock. As a result, it has invaded areas where it was not sown and displaced native grasses. Now, in some rangelands, it is a problem (Cox and Ruyie, 1986). Wind, water, and animals are means by which seeds arrive and colonize new areas (Fenner, 1985) and the precipitation is a key factor in the establishment of new seedlings. In order to understand the process by which Lehmann lovegrass is being dispersed it is necessary to understand the role that domestic animals and precipitation play in this process. The objective of this study was to evaluate if the domestic animals are dispersing the seed of this grass through its consumption and deposition of the seeds in the feces, and how the precipitation affects the establishment of new seedlings. The study was carried out at the USDA/ARS Jornada Experimental Range located 37 km north of Las Cruces, NM. Two means of seed dispersion were evaluated (seed dispersed through feces and seed broadcasted) under two levels of precipitation [long-term average (average) and long-term average + 50% (high)]. The broadcasted seed treatments had the highest number of emerged seedlings, averaging 21.9 and 19.9 seedlings m3 for the high and average precipitation levels, respectively. On the other hand, the treatments of seed dispersed through feces produced only 2.7 and 1.4 seedlings m3. At the end of the growing season the mortality rate fluctuated between 80 and 100%. The amount of rainfall had no effect on the number of established seedlings. In conclusion, the main means of Lehmann lovegrass seed dispersion is the seed broadcasted by the wind. However, the results show that domestic animals also disperse the seed of this grass, contributing to the fast colonization of new areas located far away from the seed source.