Effects of livestock grazing on nutrient retention in a headwater stream of the Rio Puerco Basin

Abstract

Sediment and nutrient loss from headwater streams of sedimentary basins in the semi-arid Southwest have been attributed to both over-grazing by livestock and to climatic cycles that influence arroyo formation. Considerable effort has been directed toward the influence of livestock grazing on riparian species abundance and diversity. Less work has concentrated on the influence of livestock on in-stream processes and communities. In contrast, considerable research has described the importance of floods as ecological organizers of riparian and benthic communities in lotic ecosystems. Here, we consider the interaction of flooding and livestock grazing on hydrologic and nutrient retention in a headwater stream of the Rio Puerto Basin. NM. We propose that grazing decreases retention of water, sediments, and nutrients by changing physical and biological features of the stream that cause the system to be less resistant to natural floods and by decreasing recovery rates when floods do occur (i.e. less resilience). This work presents our initial studies of the differing nutrient and hydrologic environments created by cattle exclosures on the Rio Seiiorito, a tributary of the Rio Puerto. Preliminary results indicate that benthic biomass and transient hydraulic storage are greater in reaches protected from cattle influences. Finally, we propose a conceptual model that predicts the implication of disturbance interaction for streams impacted by flash floods and grazing practices.

Parent Publication

• Desired future conditions for Southwestern riparian ecosystems: Bringing interests and concerns together

Citation

Sewards, Mark A.; Valett, H. Maurice. 1996. Effects of livestock grazing on nutrient retention in a headwater stream of the Rio Puerco Basin. In: Shaw, Douglas W.; Finch, Deborah M., tech coords. Desired future conditions for Southwestern riparian ecosystems: Bringing interests and concerns together. 1995 Sept. 18-22, 1995; Albuquerque, NM. General Technical Report RM-GTR-272. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. p. 135-142.