INVESTIGADORES
LOYDI Alejandro
artículos
Título:
Distribution and effects of tree leaf litter on vegetation composition and biomass in a forest-grassland ecotone
Autor/es:
ALEJANDRO LOYDI; LOHSE, KERSTIN; OTTE A.; DONATH T. W.; ECKSTEIN R. L.
Revista:
JOURNAL OF PLANT ECOLOGY-UK
Editorial:
OXFORD UNIV PRESS
Referencias:
Lugar: Oxford; Año: 2014 vol. 7 p. 264 - 275
ISSN:
1752-9921
Resumen:
Aims After abandonment of grasslands, secondary succession leads to the invasion by woody species. This process begins with the accumulation of tree litter in the forest-grassland ecotone. Our objectives were to determine the relationships between litter amounts and vegetation composition and cover along natural forest?grassland ecotones and to experimentally study the initial effects of tree litter accumulation on grassland vegetation and on microsite conditions. Methods We established eleven transects varying from 12 to 15 m in length in different forest-grassland ecotones in the Lahn-Dill highlands, Germany, and measured the mass and cover of tree litter and the cover and composition of vegetation at five sequential positions along each transect by using 1 m2 plots with five replications. In a field experiment, we established plots subjected to different litter amounts (0, 200 and 600 g.m-2) and evaluated changes in grassland vegetation, soil temperature and soil nutrient availability below the litter layer. Important Findings Tree litter amounts decrease from 650 to 65 g.m-2 across the forest-grassland ecotone. Vegetation changed from shrubs and annual species (adapted to more stressful conditions) in the forests edge to grasses, rosettes and hemi rosette species (with higher competitive abilities) in the grassland. These anthropogenic forest-grassland ecotones showed abrupt edges and the two adjacent ecosystems were characterised by different species pools and functional groups. In the field experiment, the presence of a litter layer reduced vegetation biomass and cover; the species richness was only reduced in the treatment with high litter (600 g.m-2). Additionally, adding litter on top of vegetation also reduced thermal amplitude and the number of frost days, while increasing the availability of some nutrients, such as nitrogen and aluminium, the latter being an indicator of soil acidification. Adding a tree litter layer of 600 g.m-2 in grassland areas had strong effects on the composition and diversity of grassland vegetation by reducing the cover of several key grassland species. In, or near, forest edges litter accumulation rapidly change established vegetation, microsite conditions and soil nutrients.