Graduate Thesis Or Dissertation
 

The Effects of Road Noise on Pacific Chorus Frog Communication

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2z10wt39r

Descriptions

Attribute NameValues
Creator
Abstract
  • Amphibians are experiencing global population declines and are one of the most threatened groups of vertebrates. This can be attributed to multiple environmental stressors such as habitat loss, disease, invasive species, and climate change. For vocal amphibian species, loss of acoustic habitat due to anthropogenic noise may be yet another environmental stressor. The Pacific chorus frog (Pseudacris regilla) is the most common vocal species of the Pacific Northwest. It is described as a generalist that can occupy human-dominated habitat types, including agricultural and urban wetlands. As such, this species is exposed to anthropogenic noise which can interfere with vocalizations during the breeding season. We hypothesized that Pacific chorus frogs would alter the spatial and temporal structure of their breeding vocalizations to accommodate a widespread anthropogenic stressor: road noise. We compared Pacific chorus frog call structure and ambient road noise levels at 8 sites along a gradient of noise exposures in the Willamette Valley, Oregon, USA. We used both passive acoustic monitoring and directional recordings to determine source level (i.e. amplitude or volume), dominant frequency (i.e. pitch), call duration, and call rate of individual frogs and to quantify ambient road noise levels. We found that Pacific chorus frogs significantly reduced their call rate at relatively higher levels of ambient road noise, leading to a reduction in the amount of total time spent calling. We found no other changes to call structure (e.g. frequency and duration). The absence of additional call structure changes to mediate the impact of road noise resulted in a drastic reduction in the active call space of an individual frog. Coupled with the decrease in call rate, this signifies that communication is significantly reduced both spatially and temporally. This may have implications for the reproductive success of this species, which appears to rely on specific call repertoires to portray relative fitness and attract mates. Reduction of acoustic habitat by anthropogenic noise may emerge as a compounding environmental stressor for an already sensitive taxonomic group.
License
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details NelsonDanielleV2016.pdf 2017-08-17 Public Download