The Madrean Archipelago Ecoregion is a biodiversity hotspot extending from southeastern Arizona into northern Mexico that is increasingly threatened by changes in precipitation patterns, increased wildfire interval and intensity, and increased use of ground and surface water resources by a growing human population. Restoration practitioners seek to conserve the ecological and cultural values of this region using a variety of watershed restoration techniques such as gabions, check dams, one-rock dams, and cross vanes. Research has shown the positive effect of these structures on the hydrology of a watershed but less is known about the ecological effects. Vegetation dynamics in the Madrean Archipelago region are primarily driven by water availability, thus we hypothesize that these changes in hydrology will increase the abundance of vegetation and change species composition at restoration sites. To evaluate the effect of watershed restoration structures on local vegetation, field data was collected in August through September for five growing seasons from 2015 to 2019. We measured the frequency of perennial species using nested quadrats, recorded cover in the quadrats, and recorded species data at three project sites. Data was analyzed to determine changes in species composition and abundance, occurrence of wetland species, and native/non-native species dynamics.
Results/Conclusions
Preliminary results showed higher frequencies of perennial plant species at treatment sites after four years though the strength of response varied by site. Results indicated that the installation of restoration structures can act as a disturbance on the landscape with subsequent recovery exhibiting expected successional dynamics. Results also indicated that the level of degradation prior to restoration may be an important factor in restoration success, supporting the use of ecological threshold models in restoration planning.