Frogs, Fish and Forestry: An Integrated Watershed Network Paradigm Conserves Biodiversity and Ecological Services

Abstract

Successfully addressing the multitude of stresses influencing forest catchments, their native biota, and the vital ecological services they provide humanity will require adapting an integrated view that incorporates the full range of natural and anthropogenic disturbances acting on these landscapes and their embedded fluvial networks. The concepts of dendritic networks, disturbance domains, the stream continuum, and hydrologic connectivity can facilitate this integration. Managing catchments based on these combined concepts would better maintain all the components of watersheds and the interacting processes that comprise their ecological integrity. To examine these ideas, I review riparian protection regulations in the Pacific Northwest of the United States, regulations considered by many to be among the best available, and evaluate their ability to protect headwater amphibians. I present evidence for the inadequacy of these rules to maintain robust populations of these amphibians, and discuss the implications of these shortcomings for downstream-dwelling coho salmon. Emphasizing headwaters (1st to 3rd-order channels), I discuss disturbance regimes and how differences in their fluvial and geomorphic processes determine the structuring of channels, their internal environments, and the composition of the resident biota. I examine amphibian dependence on specific channel attributes, and discuss links between their abundances, altered attribute states, and natural and anthropogenic disturbances. Using these examples, I discuss the limitations of current protections to maintain key attributes necessary to support robust populations of headwater amphibians, and via hydrologic connectivity, many downstream organisms. I propose that the goal of maintaining whole catchment biodiversity and ecological services could be improved by managing watersheds based on integrating science-based network organizing concepts and evaluating and adjusting outcomes with a suite of responsive bio-indicators

Metrics of disturbance in a redwood forest ecosystem: responses of stream amphibians to repeated sediment infusions

“…The relative status of populations of these amphibians in headwater streams of redwood and other Pacific Northwest rainforests can indicate the stability and resistance/resilience of an entire catchment network (Welsh ). For example, their presence and relative numbers in streams can indicate whether appropriate conditions exist to support anadromous fish runs (Welsh et al.…”

Obligate crayfish burrow use and core habitat requirements of crawfish frogs

“…However, until recently, amphibian habitat use outside of breeding has not been emphasized (for exceptions see Semlitsch and Jensen 2001, Rittenhouse and Semlitsch 2007, Rittenhouse et al 2009). From the perspective of breeding amphibians, wetlands cannot be considered in isolation from their surrounding habitat; when considering conservation of aquatic‐breeding species the terrestrial habitat that surrounds them must be taken into account (e.g., Semlitsch 1998, Semlitsch 2006, Welsh 2011). Semlitsch and Bodie (2003) proposed a stratified wetland buffer system to protect the surrounding terrestrial habitat.…”

Aquatic biodiversity in forests: a weak link in ecosystem services resilience

“…Native aquatic species in forests follow longitudinal patterns related to stream size as well, with increasing fish diversity in downstream reaches (Roper and Scarnecchia 2001). Conversely, headwaters are recognized as hotspots for amphibian diversity in river networks of the Northeast Pacific Rim (Olson et al 2007;Welsh 2011). Overall, aquatic ecosystems in forests can be envisioned as a mosaic of complex multi-states within an ecosystem ( Fig.…”