Loss of phenolic compounds from leaf litter of creosotebush [Larrea tridentata (Sess. & Moc. ex DC.) Cov.] and tarbush (Flourensia cernua DC.)

We examined loss of organic matter (OM) and phenolics from leaf litter of two shrubs that are invasive in the Chihuahuan Desert. Fiberglass bags (1-mm mesh) containing creosotebush [Larrea tridentata (Sess. & Moc. ex DC.) Cov.] or tarbush (Flourensia cernua DC.) leaf litter were placed below shrubs in two positions (soil surface and 5 cm below-ground) and removed at several intervals up to 90 days during winter (creosotebush and tarbush) and spring (creosotebush). Over the 90-day sampling interval, OM loss from creosotebush and tarbush during the winter sampling period was low for both surface and buried litter, ranging from 1.7% to 5.2%. Losses of OM from creosotebush litter during the spring were much greater (75.1% and 33.5% for buried and surface samples, respectively). Total phenolic losses after 90 days were 1.6%, 4.8%, 21.6% 13.5%, 87.1%, and 43.5% for winter buried creosotebush, winter surface creosotebush, winter buried tarbush, winter surface tarbush, spring buried creosotebush, and spring surface creosotebush litter, respectively, while losses of condensed tannins for the same samples were 45.8%, 56.1%, -34.0%, -41.8%, 91.1%, and 67.4%. Nordihydroguaiaretic acid loss from creosotebush litter was 25.4%, 18.3%, 95.2%, and 66.7% for winter buried, winter surface, spring buried, and spring surface samples, respectively, over the 90-day interval. Losses of OM and phenolics were generally greater in buried vs. surface and spring vs. winter samples, and losses typically occurred during the last 30-45 days. (C) 2004 Elsevier Ltd. All rights reserved.