Landscapes Forest and Global Change - ESA - Escola Superior ...

P. González-Moreno et al. 2010. The influence of spatial structure on natural regeneration and biodiversity
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diversity variables using correlation analyses. Regeneration and plant diversity were calculated
as the average of the values of all inventory plots within each patch.
3. Results
3.1 Vegetation context
Plant diversity declined with increasing distances to oak vegetation, riparian vegetation and
shrubland (Table 1). However, proximity to riparian vegetation was not influencing herbaceous
diversity. Surprisingly, the diversity index for flesh-fruited woody species had significant
positive relationship to distance to agriculture fields. Considering distance to oak, shrubland and
riparian vegetation, the algorithm favouring downhill dispersion had higher correlation strength
than the others (weighted downhill > Euclidean > weighted uphill). In contrast to plant diversity
indices, seedling abundance of Q. ilex showed only a strong negative relationship to distances to
oak (Table 1). Abundance of Q. ilex seedlings showed also similar pattern of differences among
algorithms than plant diversity indices (Euclidean = weighted downhill < weighted uphill).
3.2 Patch geometry
Patch area showed negative relationship with Shannon diversity index for all species (ρ=-0.59,
P=0.05), herbaceous species (ρ=-0.60, P=0.05), and woody species although the latter
relationship was not significant. Shape index did not correlate significantly with any of the
Shannon diversity indices. Abundance of Q. ilex seedlings did not present significant relation
with any of the geometry variables considered, although there was a positive trend with shape
index (ρ=0.13, P