Assessing and Optimizing a Rapid Road-Crossing Protocol for Aquatic
Organismal Passage
Abstract
For decades managers have sought to mitigate the effects of
fragmentation on wildlife. In aquatic ecosystems, fragmentation strongly
affects headwater streams due to the architecture of riverine networks
and the abundance of road crossing culverts. Standardized road crossing
assessments offer an alternative to historical methods in facilitating
the identification and prioritization of barriers for restoration.
However, the ecological relevance of these assessments are seldom
empirically investigated, and most assessments assume homogenous
environmental and biotic conditions observed during snapshot surveys.
Our goal was to assess both the efficacy and assumptions of the widely
adopted Southeastern Resource Aquatic Partnership’s (SARP AOP) Road
Crossing Assessment for predicting fish passage. We used model selection
of generalized linear mixed models to compare SARP AOP scores to
observed movement calculated through mark-recapture. We also compared
the SARP AOP score with a modified version of the score that included
alterations to better reflect local environmental conditions. Although
limited in scope, our results suggest an overall lack of support for the
efficacy of the SARP AOP score in predicting fish passage and only
marginal improvements under the modified score. This study is an
important first step in our ability to modify standardized score
calculations to increase efficacy without additional surveys. Regardless
of the scoring framework efficacy, standardized road crossing surveys
remain highly useful in collecting information related to potentially
harmful structures (i.e., failing infrastructure). Future studies should
further explore how to improve the efficacy of these assessments, which
represent a promising tool to facilitate efficient and effective
restoration.