Shiels, A.B., West, C.A., Weiss, L., Klawinski, P.D. &
Walker, L.R. 2008. Soil factors predict initial plant
colonization on Puerto Rican landslides. Plant
Ecology 195: 165–178.
Abstract:
Tropical storms are the principal cause of
landslides in montane rainforests, such as the Luquillo
Experimental Forest (LEF) of Puerto Rico. A
storm in 2003 caused 30 new landslides in the LEF
that we used to examine prior hypotheses that slope
stability and organically enriched soils are prerequisites
for plant colonization. We measured slope
stability and litterfall 8–13 months following landslide
formation. At 13 months we also measured
microtopography, soil characteristics (organic matter,
particle size, total nitrogen, and water-holding
capacity), elevation, distance to forest edge, and
canopy cover. When all landslides were analyzed
together, plant biomass and cover at 13 months were
not correlated with slope stability or organic matter,
but instead with soil nitrogen, clay content, waterholding
capacity, and elevation. When landslides
were analyzed after separating by soil type, the
distance from the forest edge and slope stability
combined with soil factors (excluding organic matter)
predicted initial plant colonization on volcaniclastic
landslides, whereas on diorite landslides none of the
measured characteristics affected initial plant colonization.
The life forms of the colonizing plants
reflected these differences in landslide soils, as trees,
shrubs, and vines colonized high clay, high nitrogen,
and low elevation volcaniclastic soils, whereas herbs
were the dominant colonists on high sand, low
nitrogen, and high elevation diorite soils. Therefore,
the predictability of the initial stage of plant succession
on LEF landslides is primarily determined by soil
characteristics that are related to soil type.