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

J. Russell et al. 2010. Developing models and processes to aid decision support for integrated land management
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across space and time. To monitor changes in the composition of the forecasts, BAP tracks the
proportion of habitat types and diversity of the forest using the following metrics. 1) Areaweighted
age is a single value at each time step during the simulation, indicating the average
age of the entire forest. 2) Tree species distribution separates the forest into hardwood stands,
hardwood-dominated mixedwood stands, softwood stands and softwood-dominated mixedwood
stands. It provides an indication of the proportion of the FM area expected to support each
habitat type at each time step. 3) Species presence indicates the extent of coverage of each tree
species over the landscape. 4) Species dominance takes into account both tree species presence
and relative dominance. 5) Habitat diversity was computed using a matrix showing similarity
between habitat types as a weighting factor. The habitat diversity index considers the relative
position of broad habitat types using a rating of similarity between the habitat types as a
weighting factor. The diversity equation generates a single unitless value between 0 and 1 at
each time step; 0 represents a very uniform landscape and 1 indicates the most diverse
landscape possible. Incorporated into the index are both the number of habitat types present
within the FM area and the proportion of the landscape covered by each habitat type.
Landscapes containing many habitat types distributed evenly across the area are considered
more diverse than those dominated by one habitat type, yet containing small portions of others.
Within the landscape configuration analysis, habitat types were used as class attributes because
they can be weighted by contrast. As well, different levels of distinction among habitats can be
used following the classification hierarchy. The landscape configuration analysis was comprised
of several types of biostatistical analyses:
• Patch – areas of similar characteristics based on age and species composition.
• Edge – mean edge contrast index and contrast weighted edge length.
• Core area – The impact of edge on wildlife was expected to be linearly related to the
abruptness of the habitat structure change at the edge and therefore the buffer width would
change with contrast between adjacent habitat patches.
• Adjacency – It was expected that the spatial distribution of habitat types would differ in a
managed scenario relative to a natural scenario. Consequently the proportion of adjacencies
might be different. Many species use a combination of different habitats to fulfill their
needs; therefore the adjacency of these habitats is important.
• Nearest neighbor – It was understood that a population using an isolated habitat is highly
prone to local extinction. In addition, an organism using dispersed habitat patches may not
be able to defend a sufficiently large territory from which to extract its needed resources.
The nearest neighbor metric gives an indication of the dispersion of similar habitat types.
Fine filter analysis was undertaken by developing species-specific habitat supply models. It was
recognized that the species selected would comprise an imperfect representation of the large
array of species that occupy the FM area. The selection process was based on the following
premises. 1) It is not possible to create models for all species. 2) Coarse filter analysis can
account for habitat requirements for many species. 3) Models created for a carefully selected list
of species will adequately represent the habitat needs of many other species. 4) Terrestrial
vertebrates will be selected because: they use a large range of forest features; are good
indicators of change; are the subjects of concern by the public and; approaches for analyzing
forests in terms of vertebrate habitat potential are relatively well developed. Species were
selected that represented the following classes: large terrestrial carnivorous mammals, large
ungulates, medium-sized herbivores/omnivorous mammals, medium-sized carnivorous
mammals, small mammals, raptors, birds in the order Gallinaceae and passerines (perching
birds). The following criteria were used, with the numbers relating to the weighting scheme for
each element: sensitivity to disturbance – 4; species status – 3; ability to monitor the species – 3;
habitat specificity – 2; special habitat elements – 2; functionally essential species – 2; landscape
configuration – 2; socioeconomic value – 2 and; available information – 1.
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.