Spatial
Ecology of a Grass-Shrub Steppe in Semiarid Patagonia
In this project
we analyzed the spatial relationships between and among shrub and
grass species in a mapped area of a semiarid grass-shrub steppe in
Patagonia, Argentina. Our aim was to gain an understanding of the
spatial ecology of this plant community and to develop testable hypothesis
about the processes that may have shaped the plant community and promoted
their persistence. We used advanced spatial pattern analysis techniques
to assess spatial scales and the net direction of possible grass-grass
and grass-shrub interactions, and to assess differences in spatial
pattern between species and between pairs of species, e.g. whether
the positive shrub-grass interaction applies similarly to all species.
More specifically we aimed to answer the following questions: (1)
Is the spatial distribution of the grass species random, uniform,
or clumped? (2) Are grasses spatially associated with shrubs or other
grasses? (3) Do spatial scales and direction of grass-grass and grass-shrub
interactions differ depending on the species combination investigated?
Keywords:
Facilitation, competition, spatial statistics, point pattern analysis,
grass-shrub interactions.
Publication:
- Wiegand, T.,
Kissling, W.D., Cipriotti, P.A. & M.R. Aguiar (2006):
Extending point pattern analysis to objects of finite size and irregular
shape. Journal of Ecology 94: 825–837. [Abstract]
Figure
- A categorical map of a representative 27.4m x 13m plot of the semiarid
grass-shrub steppe in Patagonia, Argentina. Top: individual
shrub species and dead material (colors) and all grass tussocks (dark
gray). Bottom: individual grass species (color), dead material
(white) and shrubs (black).
