Jonathan M Friedman, PhD (Former Employee)

Measuring precipitation in semi-arid landscapes is important for understanding the processes related to rainfall and run-off; however, measuring precipitation accurately can often be challenging especially within remote regions where precipitation instruments are scarce. Typically, rain-gauges are sparsely distributed and research comparing rain-gauge and RADAR precipitation estimates...

Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow...

Abstract—From the mid-1800s to around 1930, monsoonal floods incised an arroyo roughly 100 m wide and 10 m deep along the lower Rio Puerco, NM, from the confluence with the Rio San Jose downstream to the mouth at the Rio Grande, causing sedimentation and flooding downstream. Since the 1930s, the channel has greatly narrowed, a densely vegetated floodplain has developed, the arroyo has...

Local abiotic and biotic conditions can alter the strength of exotic species impacts. To better understand the effects of exotic species on invaded ecosystems and to prioritize management efforts, it is important that exotic species impacts are put in local environmental context. We studied how differences in plant community composition, photosynthetically active radiation (PAR), and...

Investigation of the water sources used by trees of different ages is essential to formulate a conservation strategy for the riparian tree, P. euphratica. This study addressed the contributions of different potential water sources to P. euphratica based on levels of stable oxygen and hydrogen isotopes (δ18O, δ2H) in the xylem of different aged P. euphratica, as well as in soil water and

Old, multi-aged populations of riparian trees provide an opportunity to improve reconstructions of streamflow. Here, ring widths of 394 plains cottonwood (Populus deltoids, ssp. monilifera) trees in the North Unit of Theodore Roosevelt National Park, North Dakota, are used to reconstruct streamflow along the Little Missouri River (LMR), North Dakota, US. Different versions of the...