HR: 1340h
AN: B23A-1041    [Abstracts]
TI: Non-native Vegetation Removal and Shallow Alluvial Ground Water Along the Rio Grande, New Mexico
AU: * Martinet, M C
EM: conuco8@unm.edu
AU: Thibault, J R
EM: jrtebo@sevilleta.unm.edu
AU: Cleverly, J R
EM: cleverly@sevilleta.unm.edu
AU: Dahm, C N
EM: cdahm@sevilleta.unm.edu
AB: Major efforts are underway to remove non-native plant species from the riparian forest along the Rio Grande. Reasons for removing non-native species include reducing the potential for catastrophic fires, increase opportunities for native plant establishment and growth, and to conserve water resources of the Rio Grande ecosystem. This study is an initial look at the effect that recent vegetation removal efforts have had on shallow alluvial ground water. Depth to water table was collected every 30 minutes during the growing season for 2000 to 2002, pre-removal of non-native vegetation, and is compared to data collected during 2004, post-removal. 2003 was a transition period for vegetation removal efforts. Depth to ground water data were collected from a 2 inch (51 mm) PVC groundwater monitoring well instrumented with a Solinst Levelogger (Model 3001) pressure transducer. Data from July and August were used to calculate diurnal maximum and minimum water table depths, which correspond to peak plant activity (i.e evapotranspiration) and lowest plant activity, respectively. Diurnal water table fluctuations (i.e. max depth-min depth) were averaged over the two month period for each year and ranged from 4 to 6 cm. Average depth to water tables were calculated for each year and ranged from 1.6 to 1.7 meters.We hypothesized that the average groundwater fluctuation and mean average depth to water table will be greater in pre-removal years (2000 to 2002) compared to the post-removal year (2004). Wilcoxon-Mann-Whitney non-parametric analyses were conducted to test this hypothesis. Pre-removal groundwater fluctuations were statistically greater (alpha = 0.05) than post-removal than post-removal, but average depth to water table was not. Analysis of the average depth to water table did not support our hypothesis due to different river discharges during this period. Removing non-native vegetation affects shallow alluvial ground water via reducing the amount that the groundwater table fluctuates during the growing season.
DE: 0481 Restoration
DE: 0483 Riparian systems (0744, 1856)
SC: Biogeosciences [B]
MN: Fall Meeting 2005