Ecosystem Guidelines for Environmental Assessment
Ecosystem Guidelines for Environmental Assessment
Ecosystem Guidelines for Environmental Assessment
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SCEPS<br />
2<br />
How much space do spatial components of ecological processes require<br />
The Framework <strong>for</strong> a Conservation Plan <strong>for</strong> the Cape Floristic Region (Cowling et al. 1999) presented a wide<br />
range of spatial components of ecological processes that occur at different scales, and require significantly<br />
different areas of natural habitat <strong>for</strong> their persistence. Some examples are given below (see Table 3).<br />
TABLE 3: SCALES AT WHICH ECOLOGICAL PROCESSES MAY FUNCTION<br />
ECOLOGICAL PROCESS<br />
SPATIAL COMPONENTS (NATURAL HABITAT)<br />
Specialist pollinator relationships<br />
Small (5-1000 ha) fragments<br />
Regular, whole-patch fires<br />
Small (ca 500-1000 ha) fragments<br />
Predator-prey processes involving smaller<br />
to larger predators<br />
Large (50 000-100 000 ha) areas to mega-sized<br />
(250 000-1 000 000 ha) areas<br />
Diversification of plant lineages in relation to macroclimatic<br />
and fine-scale geographical gradients<br />
Large (50 000-100 000 ha) areas<br />
that encompass maximal heterogeneity<br />
Plant herbivore processes involving<br />
megaherbivores<br />
Mega-sized (250 000-1 000 000 ha) areas<br />
Faunal seasonal migration<br />
Areas spanning lowland-upland gradients<br />
Diversification of plant lineages in relation to<br />
lowland-upland gradients<br />
Areas spanning lowland-upland gradients<br />
Resilience to climate change<br />
Large and steep climatic gradients along north-south<br />
and east-west axes in lowland and upland regions<br />
3<br />
Fixed and flexible spatial components of ecological processes<br />
Systematic conservation planning recognises two categories of spatial components of ecological<br />
processes: those that are spatially fixed, and those that are spatially flexible. Both are described below.<br />
SPATIALLY FIXED COMPONENTS OF ECOLOGICAL PROCESSES<br />
Spatially fixed components of ecological processes capture processes associated with clearly defined,<br />
physical features in the landscape. There are no alternative corridors or vegetation boundaries <strong>for</strong><br />
accommodating them, so they are unique and require special attention. An example is plant diversification<br />
along soil interfaces, which can occur at varying scales. The spatial component (the interface) can<br />
consist of a strip just a few metres wide where contrasting soils or rock types meet and where plant<br />
speciation is known to occur. In other situations, the interface can extend over wide areas such as<br />
SPATIAL COMPONENTS OF ECOLOGICAL PROCESSES : 81
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