1.7 Ecosystem approach to biodiversity

Landscape level concepts and the ecosystem approach to biodiversity management

Biodiversity at the landscape level is determined by a combination of physiography, climate, and various natural disturbance processes that in turn influence patterns of floral and faunal distribution.

See Figure 2. Biodiversity maintenance levels

The concepts for landscape level biodiversity are:

1. Forest habitats can be grouped into three categories at the landscape level: early seral stage, mid-seral stage and late seral stage (old growth). Species diversity is generally greatest in early and late seral stages.
2. Vertebrates tend to be associated with the structural attributes typical of a seral stage at a stand scale, rather than with stand age per se. It is therefore possible to maintain populations of most vertebrate species by providing the necessary structural attributes. The coarse filter approach provides for most of this.
3. Some old growth dependent species are believed tied to the interior microclimate conditions of late seral forests. These species include some plants, especially epiphytes, and invertebrates. Thus, to maintain populations of these species, it may be necessary to preserve blocks of old growth sufficiently large to provide suitable interior microclimate conditions.

Maintaining landscape level biodiversity involves managing:

• Seral stage distribution (appropriate for a particular ecosystem) including old-growth retention and representation
• Temporal and spatial distribution of the cut and leave areas (patch size distribution; minimizing habitat fragmentation and formation of excessive edge habitat)
• Forest interior habitat
• Landscape connectivity (to provide dispersal and movement corridors for forest and range dwelling organisms)
• Stand structure
• Species composition