»Soils and Vegetation
Vital Signs Included in Protocol
- Bare ground
- Biological soil crusts
- Soil erosion (wind and water)
- Soil hydrologic function
- Plant community composition
(Invasive/Non-native Plants, Landscape Patterns and Dynamics)
Parks Where Protocol Will Be Implemented
BIBE, CAVE, FODA, GUMO, WHSA
Justification/Issues Being Addressed
Soils and plants provide the foundation for productivity in terrestrial ecosystems. In the arid and semi-arid ecosystems of the CHDN, soil type, topographic position, and condition have direct influence on rates of mineralization, nutrient cycling, retention of moisture, and susceptibility to erosion (Monger and Bestlemeyer 2006, Schlesinger et al. 2006, Snyder et al. 2006, Duniway et al. 2007). In turn, these processes influence plant production, distribution, water runoff, and sedimentation loads in surface waters (Wondzell et al. 1996, McAuliffe 2003). Soil and plant communities provide the structural template and habitats for a wide array of fauna and are key resources that affect biotic diversity.
The arid and semi-arid “Desert” ecosystem comprises approximately 85% of total CHDN park area. Throughout the last century, the predominance of desert grasslands have diminished and woody dominated communities have expanded in the Chihuahuan Desert as a complex and interactive function of land-use, climate, and species interactions (Van Devender 1995, Peters 2001, Peters et al. 2006). Region-wide losses of grass-dominated communities have resulted in loss of habitats for grassland obligate species and changes in fire-regimes at a landscape level. Continued loss of grass-dominated communities could lead to overall loss of biotic diversity, particularly as grassland-shrubland ecotones disappear and desert plant communities become less heterogeneous in CHDN parks.
Conservation of soils is essential for long-term protection of biotic productivity. Monitoring attributes that relate information about soil condition and process, along with structure and composition of key plant communities micro- (plot level) and sub-landscape scales will help identify the potential for maintaining biological integrity and function in CHDN park units (Herrick et al. 2002).
This protocol will establish long-term monitoring plots that will quantify network- and park-wide changes in key plant communities and their associated soil properties in upland communities. These monitoring plots are not manipulative and therefore do not address causal relationships or functional questions about the ecosystems, but rather establish a basis for quantifying changes in the soils and vegetative communities.
Although CHDN parks encompass a wide range of plant communities, from desert grasslands to saltbush, mesquite and creosotebush at low elevations to mixed-conifer communities at the highest elevations, financial and logistical constraints require that we limit our objectives to a subset of these communities. We propose to conduct long-term monitoring on desert grasslands, desert shrub communities, and the grassland-shrubland ecotone within network parks because this physiognomic class collectively represents a large proportion of each park, captures several focal communities of interest, and provides a common theme among all parks (as opposed to a disjointed set of ‘favorites’ at each park), thereby increasing our ability to discern landscape-scale changes in upland vegetation and soils arising from drought, fire, exotic plant invasions, and other biotic and abiotic disturbances.
The data developed from these plots will serve two very important purposes: 1) these data will provide a quantifiable framework from which to build adaptive management policies, and 2) these data will provide a baseline from which to establish additional scientific studies, for example those addressing cause and effect relationships. Without a basic understanding of the resources and processes present within park boundaries, land managers cannot hope to make informed decisions about how to conserve these resources into the future.