Conceptual Restoration Plan Update: Phase I
Other factors have been initially evaluated during Phase 1 of this CRP update project and will be further evaluated during Phase 2, including the following:
General wildlife use
General Wildlife Use
While general wildlife use of the Project Area has been mentioned and will be considered in detail during Phase 2 analysis and evaluation of protection and restoration efforts.
There are over 400 species of birds that utilize this reach of the Middle Rio Grande. In order to benefit these diverse species, habitats present must be diverse in structure, plant species composition and patch size. Generally, the abundance of breeding birds increases with the complexity and density of vegetation structure, which is thought to be related to the increased food, cover, or nest substrate it provides (Crawford et al. 1996). Along the Rio Grande, the highest breeding densities typically have been found in marshes, cottonwood stands with a well-developed shrub understory, and in tall shrub stands (Hink and Ohmart 1984; Hoffman 1990; Thompson et al. 1994; Stahlecker and Cox 1997). Within this woodland type, avian abundance is approximately four times greater along the riverward and landward edges of the bosque than in the interior of the stand (Hink and Ohmart 1984). Bosque stands with a sparse understory generally support fewer breeding birds. Stands of intermediate age or structure vary widely in breeding bird use among the studies conducted (Farley et al. 1994), but in light of the general lack of natural cottonwood and willow regeneration along the Rio Grande, are important for their potential to develop into mature stands.
Some specific wildlife uses also should be considered. This includes use of riparian habitat by elk and other nondomestic ungulates, as well as cattle grazing. As noted above, avian use is high in the Middle Rio Grande migratory flyway.
Phase 2 will consider shifts in wildlife use based on trend analysis of water availability, habitat establishment and viability, patch size and plant succession. A detailed analysis of patch mosaic and related wildlife habitat use will be conducted at this phase. The patch mosaic has been introduced in various documentation (Crawford et al 1993; Najmi et al 2005; USACE 2011; and Muldavin et al 2019). A patch mosaic can be viewed at the landscape scale targeting a mixture of habitat types such as a riparian gallery forest mosaic (targeting a combination of tree, shrub, grassland/herbaceous and meadow/wetland communities) (USACE 2011). The patch mosaic should also consider uneven-aged stands of trees, shrubs, wetlands and other community types (Najmi et al 2005).
Communities for habitat but also specific wildlife groups (birds, fish, wildlife corridors, etc.) should be considered for evaluation of habitat types or targets. This patch mosaic can provide linkages between terrestrial and aquatic habitats (Muldavin et al 2019) that can benefit each other and allow for wildlife corridor use.
Current land use consists of grazing on both public and private lands, and there are several grazing allotments within the Project Area managed by the U.S. Bureau of Land Management. Much of the area is farmland, and alfalfa is the dominant crop. Some landowners have made the decision to convert land that was previously used for agriculture to wetland and wildlife habitat. There are some existing conservation easements with the Rio Grande Agricultural Land Trust on the Project Area as well as some completed Partners Program-funded projects such as the Rhodes Property and Boys and Girls Club who have conducted restoration efforts on their properties. Whether the land has been designated as official conservation easements or not, the agricultural land can create a bridge with river, bosque, and floodplain habitat and should be evaluated as part of the overall system.
There is an extensive amount of recreation in the Project Area, including hunting, fishing, hiking, and birdwatching. The Armendaris Ranch offers guided recreational experiences, but primarily on parts of the ranch not in the Project Area. The Camino Real de Tierra Adentro National Historic Trail passes through the Project Area, but it is not clear whether it receives many visitors. The proposed Rio Grande Trail would likely pass through the Project Area, although the alignment has not been finalized and there is no schedule for completion. These and other potential recreational uses should be considered during Phase 2 planning efforts.