Soundscape and Landscape Ecology - Soundscape Ecology: Principles, Patterns, Methods and Applications - page 16

Fig. 1.8 Main attributes of patches: shape and size, edge irregularity, spatial arrangement, diversity
By geographic landscape, we mean the description of a specific region in terms
of land form, stream and river configurations, distribution of lakes, dry depressions,
slope characteristics, and associated patterns. The study of the landscape from a
geographic perspective has utilized the hierarchical theory by which elementary
units, the patches, are aggregated in further higher-order units that in turn are
components of a superior system. Often across such hierarchies is possible to
observe a fractal structure. According to the geographic perspective are distin-
guished, at least at a specific scale, patches from a more homogeneous matrix.
Patches represent the spatial unit of a land mosaic and their main characteristics
depend on shape and size, edge irregularities, spatial distribution in the mosaic,
and diversity (Fig. 1.8 ), and consider fragmentation as a resultant process of
disturbance.
The relationship between the geographic landscape and the ecological landscape
are evident when we attribute functions to the observed spatial patterns. In these
terms, size, dimension, internal structure, and distance of each patch from others are
attributes that in turn affect distribution and diversity of the organisms (plants,
animals, virus, bacteria, algae, etc.).
It is well known that the dimensions of patches are essential to maintain a stable
population or a more diverse community and that the lengths of the borders attract
ecotonal species and discourage habitat-interior (core) species. The fragmentation
of homogeneous stands strongly affects the survivorship of interior species and
facilitate the intrusion of alien species and predators. Fragmentation in the different
phases, as outlined in Fig. 1.9 , may have several effects on distribution and
movements of species discouraging non-ecotonal species. However, margins in
nontropical ecosystems are very attractive systems for many species and in this
apparent paradox ecology can contribute to explaining the different constraints.
The ecotones represent important structures to understand the functioning of a
landscape; in fact, the margin between one system and another is a tension zone
through which energy, nutrients, organisms, and information pass. Ecotones exist at
all ecological scales from a few millimeters to thousands of kilometers across the
biomes. The ecological frontiers created by the juxtaposition of different systems
originate gradients with which species enter into contact and can suffer or benefit
from the ecological constraints.