Document: PAT-3-83-15

Assessing representation of terrestrial ecological diversity among current and potential conservation lands in the Mojave Desert Ecoregion

COMER, P.J.*, D.DORFMAN and B.CHOLVIN

The Nature Conservancy, Boulder CO 80303 USA ¹

Abstract:
Biological conservation requires that a wide range of species assemblages and environmental gradients be represented within conservation lands. New approaches and tools are needed to efficiently assess terrestrial ecological diversity at regional scales, and our assessment of the Mojave Desert Ecoregion provides one example. We developed a two-tiered classification of terrestrial vegetation for the ecoregion. Over 130 plant associations documented in the National Vegetation Classification System defined the fine-scale units. Documented similarities in local environment (e.g. elevation zone, driving process, substrate) enabled us to aggregate plant associations into 19 ecological groupings. Tools to evaluate vegetation distributions included vegetation maps, with cover types linked to the classification; and documented site-specific locations. Environmental gradients were identified with a landform classification using slope angle and slope position measurements from a digital elevation model. Steep sloping landforms were modified by aspect and rolling-flat landforms were modified using a flow accumulation model. Landforms were further modified by one of six substrate classes. With all landforms additionally modified by one of six elevation zones, more than 350 unique land types represent the physical gradients of the ecoregion. Existing conservation lands were mapped and potential conservation lands were located where site-specific locations of targeted species and species assemblages had been identified. Overlay of all spatial data allowed us to quantify and evaluate current representation and alternative combinations of potential conservation lands that would meet stated conservation goals.

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This abstract is being presented at: 3:30 PM in session:
CONSERVATION ECOLOGY