Channel changes following human activity exclusion in the riparian areas of Bonita Creek, Arizona, USA

Abstract

Riparian areas provide many ecosystems services to humans that have been utilized for thousands of years and are the main reason why these areas are degraded. Their importance for maintaining biodiversity and stream channel health is even more important in semi-arid and arid region, such as the south-western United States. A common practice to protect riparian areas and streams in the region is the exclusion of human activities with a prime example the Gila Box Riparian National Conservation Area. In this study, we examine if the exclusion of human activities has benefited the Bonita Creek that flows through this conservation area. Cross sections at five locations along Bonita Creek were taken in 1994 and 2013. Based on the comparison of the thalweg depth, the width-depth ratio, the channel erosion/deposition and the floodplain erosion/deposition the stream channel of the two surveys, Bonita Creek appears, in general, to be benefiting from the current exclusion of human activities. Still recovery rates are not very fast indicating landscape and ecosystem-based approaches should be adopted for more effective and sustainable conservation of the area.