SEEDLING ESTABLISHMENT UNDER NATIVE TAMAULIPAN THORNSCRUB AND LEUCAENA-LEUCOCEPHALA PLANTATION

In order to investigate the influence that plantations and clearing of native vegetation might have on plant regeneration in northeastern Me xico, seedling survival and germination (i.e., seedling emergence from the soil surface) were measured monthly in native fragments and an ex otic plantation over a one-year period. Seedlings were measured in 1-m (2) plots, using 10 replicates under each of three different treatment s: (i) dense thornscrub, (ii) semi-cleared thornscrub, and (iii) a den se L. leucocephala plantation. Seedling number peaked during summer an d early autumn, lowest number of seedlings occurred during early sprin g. Excluding grasses, 36 species were present during the study, and on ly 14 were present in L. leucocephala plantation. Thornscrub and open thornscrub had similar number of grass seedlings, whereas more forb se edlings were present in open thornscrub. Seedlings of woody species we re similar for all treatments. Under L. leucocephala germination was l ow for most species other than itself, most seedlings, however, died d uring the winter months. (C) 1998 Elsevier Science B.V.