Implementing an Operational Framework to Develop a Streamflow Duration Assessment Method: A Case Study from the Arid West United States.

Streamflow duration information underpins many management decisions. However, hydrologic data are rarely available where needed. Rapid streamflow duration assessment methods (SDAMs) classify reaches based on indicators that are measured in a single brief visit. We evaluated a proposed framework for developing SDAMs to develop an SDAM for the Arid West United States that can classify reaches as perennial, intermittent, or ephemeral. We identified 41 candidate biological, geomorphological, and hydrological indicators of streamflow duration in a literature review, evaluated them for a number of desirable criteria (e.g., defensibility and consistency), and measured 21 of them at 89 reaches with known flow durations. We selected metrics for the SDAM based on their ability to discriminate among flow duration classes in analyses of variance, as well as their importance in a random forest model to predict streamflow duration. This approach resulted in a "beta" SDAM that uses five biological indicators. It could discriminate between ephemeral and non-ephemeral reaches with 81% accuracy, but only 56% accuracy when distinguishing 3 classes. A final method will be developed following expanded data collection. This Arid West study demonstrates the effectiveness of our approach and paves the way for more efficient development of scientifically informed SDAMs.

Contemporary Land Change Alters Fish Communities in a San Francisco Bay Watershed, California, U.S.A.

Urbanization is one of the leading threats to freshwater biodiversity, and urban regions continue to expand globally. Here we examined the relationship between recent urbanization and shifts in stream fish communities. We sampled fishes at 32 sites in the Alameda Creek Watershed, near San Francisco, California, in 1993-1994 and again in 2009, and we quantified univariate and multivariate changes in fish communities between the sampling periods. Sampling sites were classified into those downstream of a rapidly urbanizing area ("urbanized sites"), and those found in less impacted areas ("low-impacted sites"). We calculated the change from non-urban to urban land cover between 1993 and 2009 at two scales for each site (the total watershed and a 3km buffer zone immediately upstream of each site). Neither the mean relative abundance of native fish nor nonnative species richness changed significantly between the survey periods. However, we observed significant changes in fish community composition (as measured by Bray-Curtis dissimilarity) and a decrease in native species richness between the sampling periods at urbanized sites, but not at low-impacted sites. Moreover, the relative abundance of one native cyprinid (Lavinia symmetricus) decreased at the urbanized sites but not at low-impacted sites. Increased urbanization was associated with changes in the fish community, and this relationship was strongest at the smaller (3km buffer) scale. Our results suggest that ongoing land change alters fish communities and that contemporary resurveys are an important tool for examining how freshwater taxa are responding to recent environmental change.

Efficacy of combining interview techniques in detecting deception related to bio-threat issues.

The purpose of this project was to assess the detecting deception efficacy of three well-validated "detecting deception" methods - i.e., forced choice testing (FCT), modified cognitive interviewing (MCI) and autobiographical implicit association testing (aIAT) - when applied to the issue of bio-threat. The detecting deception accuracies of FCT and MCI were 81% and 75%, respectively. Although the aIAT mean response times in block 5 differed significantly between deceptive and truthful persons, the classification accuracy was low. FCT alone reduced the group of 64 persons to 11 and detected 50% of the liars; the false positive rate was 9%. MCI alone reduced the group of 64 to 24 and detected 92% of the liars; the false positive rate was 54%. When FCT was paired with MCI, 75% of liars were detected and the false positive rate was 13%. Forced choice testing and MCI show promise as methods for detecting deception related to bio-threat under low-base-rate conditions. These methods took little time, enhanced the odds of detecting deceptive individuals and exhibited high positive likelihood ratios, suggesting that they have merit as screening tools. The aIAT required more time and was less accurate but may still serve as a useful screening tool.