Distribution of amphibians in wadeable streams and ponds in western and southeast Oregon, Information Report 2009-02

Identification Information

Citation

Originator: Bangs, B.L. and K.K. Jones

Publish Date: March 2009

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: cedric.x.cooney@odfw.oregon.gov

Description

Abstract: The Oregon Conservation Strategy (ODFW 2006) identified monitoring needs for 17 amphibian species native to the state of Oregon that are designated as “Strategy species”, or Species of Greatest Conservation Need (per USFWS requirements for State Wildlife Action Plans). The distribution of many species of amphibians in western Oregon is sparsely documented (Oregon Conservation Strategy, page 27). Although a broad-scale survey for amphibian presence would provide much information about amphibian distribution, most studies have focused on limited areas. One cost-effective approach is to combine amphibian observational surveys with existing aquatic habitat surveys conducted as part of the Oregon Plan for Salmon and Watersheds (OCSRI 1997). The Oregon Plan has been in place since 1997 and the monitoring component provides a survey framework for streams in the lower Columbia River and Oregon coast drainages. The sampling framework is also compatible with implementation of the aquatic components of the Conservation Strategy, as demonstrated by this study. This study describes the presence of amphibians in and along wadeable streams in coastal and lower Columbia River drainages of Oregon, ponds and sloughs in the Willamette Valley, and selected streams in the Great Basin of southeast and central Oregon. As a component of monitoring under the Oregon Plan, the Aquatic Inventories Project (AIP) conducts aquatic habitat surveys at randomly selected and spatially balanced sites across all 1st through 4th order streams (wadeable) in coastal and lower Columbia River drainages. The purpose of the habitat surveys is to describe stream morphology, instream physical habitat, and riparian vegetation. Because the surveyors were already observing features within and alongside the stream channel, they were able to record observations of amphibians. The amphibian component was consistent with the survey protocol used by the US Geological Survey’s Amphibian Research and Monitoring Initiative. The advantage of coupling an amphibian component with the OR Plan aquatic surveys was that it not only was an efficient use of resources, but more importantly, provided information using a statistically rigorous survey design across a broad geographic area. In the summer of 2006, AIP began collecting amphibian occurrence data during physical stream habitat surveys as a pilot study to determine if our standard survey protocol could be modified to document distribution of amphibians characterized as Strategy Species under the Oregon Conservation Strategy. During the summer season, field crews observed four strategy species of amphibians and eleven amphibian species total. The potential to use these data to fill the gaps within the known current distribution of amphibians and to potentially develop a habitat based distribution models for these species led to the summer 2007 work. Amphibian data are also collected during four other survey projects, and although the site selection procedure does not conform to the same statistical standards as the Oregon Plan survey design, the projects offer a number of opportunities to collect amphibian occurrence information over a wide variety of habitats. The amphibian observations from these four projects are also included in this report. The four projects are as follows: • AIP conducts aquatic habitat surveys on selected streams throughout the state. • AIP conducts aquatic habitat surveys at stream habitat restoration projects in Western Oregon. • Surveys to document the distribution of Oregon chub also record amphibian data from over 1,000 pond and slough sites within the Willamette Valley floodplain since 1991. • The Native Fish Investigations Project began a study in 2007 to document the distribution and abundance of Redband Trout in the Great Basin region of Eastern Oregon. Surveys in the summer of 2007 occurred in 8 of Oregon’s 10 ecoregions (Figure 1)(Omernick 1994). Ecoregions are relatively large areas defined by distinctive geographic and ecological characteristics; flora and fauna communities and geographic conditions are typically distinct. Ecoregions provide an ecological framework for describing amphibian distribution across the state. The goals of our 2007 work were to: • Increase the consistency, efficiency and ability of habitat crews in identifying amphibians through improved training. • Increase knowledge of distribution and habitat associations of amphibians in streams in western Oregon (location, stream size and type), and infer distribution in all coastal and lower Columbia drainages. • Describe temporal changes in stream habitat use by amphibians (seasonal, annual). • Estimate surveyor bias by comparing standard crew data with intensive resurveys. • Describe distribution of amphibians in ponds, sloughs and other off channel aquatic habitats in the Willamette Valley. • Describe distribution of amphibians in the Great Basin of eastern Oregon. Many of Oregon’s amphibians rely on aquatic habitats at some point of their life, either for breeding and juvenile development or to inhabit as adults. Most aquatic amphibians breed from late winter to early summer, and many adults remain in or near their breeding sites into the summer. Most tadpoles and juvenile amphibians are also active in and occupy aquatic habitats during the summer. The aquatic habitat and redband trout surveys are appropriate opportunities to observe species and life stages (breeding adults, tadpoles and juveniles) that occupy aquatic or riparian habitats during the summer. Likewise the Oregon chub surveys are likely to observe amphibian species and life stages in ponds and sloughs during the spring and fall. These types of surveys are an efficient and cost-effective means to collect information on amphibian species that are closely tied to aquatic habitat throughout their life cycle. Amphibian species that are more terrestrial in nature may be better surveyed through a different approach.

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Geographic Extent: Oregon Coast range and lower Columbia basins

Status: Final

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Format: PDF File

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Is a physical copy maintained for reference at Headquarters? No