The purpose of this project is to develop statistical methods for marine bird surveys, to help guide placement of offshore renewable energy facilities, such as wind farms, to reduce potential impacts on birds. Marine birds are highly mobile animals, and detecting bird “hotspots” and “coldspots” in the ocean poses a challenge. The statistical methods we are developing to address this challenge are being used to help maximize the value of historical seabird data and plan future survey efforts.
Why We Care
An understanding of marine bird distribution and abundance is important to environmentally responsible development of offshore renewable energy resources such as wind farms. NCCOS is working with the Department of the Interior’s Bureau of Ocean Energy Management (BOEM) Office of Renewable Energy Programs (OREP) and the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center (PWRC) to develop statistical methods and analyses that will contribute to guidelines for design and interpretation of offshore marine bird surveys.
With the passage of the Energy Policy Act of 2005, BOEM acquired responsibilities for renewable energy activities, including wind power development , in a part of the ocean known as the Outer Continental Shelf (OCS). The OCS is the portion of the ocean that extends from state-managed waters to the edge of the U.S. Exclusive Economic Zone, approximately 200 nautical miles offshore. As part of this responsibility, BOEM is preparing detailed environmental analyses of offshore renewable energy projects proposed for development. Potential direct, indirect and cumulative impacts of projects on the human, coastal and marine environments must be evaluated in order for BOEM to make sound decisions about managing renewable energy activities and developing ways to avoid or minimize impacts.
The launch of the Secretary of the Interior’s “Smart from the Start” wind energy initiative for the Atlantic OCS is aimed at promoting the rapid and responsible development of wind energy resources. Experience from land-based wind development in the U.S. and abroad, and offshore wind development in Europe, suggests that smart, data-driven location of facilities is one of the most important considerations for minimizing impacts to bird species. Discussions during the U.S. Fish and Wildlife Service (FWS) Marine Bird Science and Offshore Wind Workshop and the BOEM Atlantic Wind Energy Workshop in June-July 2011 emphasized the importance of identifying areas of persistent groupings of birds (a.k.a. “hotspots”) which may conflict with offshore wind energy development. Conversely, the identification of “coldspots,” or areas where birds do not congregate and thus may not conflict with wind energy development, is equally important.
This project will aid BOEM’s development of guidelines for marine bird surveys on the OCS. More broadly, the purpose of this project is twofold: 1) to support the sound interpretation of already-collected survey data and to maximize its usefulness, and 2) to provide a framework for planning future surveys to support the design of future monitoring and assessment efforts.
What We Are Doing
We are developing a method, using statistics, to decide how many samples we need from a survey area to show that what appear to be large groupings of birds observed in certain places in historical surveys are a real reflection of typical bird abundance at those locations, and not just random fluctuations that happened to be observed at the times surveys occurred. Conversely, our method can also show how many samples are required to be confident that large groupings of birds are not likely to occur in a particular area.
To address this challenge, we are gathering previous research on animal group size distributions, using that information to develop statistical procedures, applying these statistical procedures to actual data collected in the field, and using the results to suggest guidelines for design and interpretation of marine bird surveys for offshore renewable energy siting. We are using a large database of historical at-sea marine bird survey data developed and maintained by our partners at the USGS PWRC (Compendium of Avian Information, see “Data” section below).
Sampling guidelines will be used to support the interpretation of existing datasets, and the design and interpretation of future monitoring and assessment efforts. Our work includes both development of a general method that is expected to be applied nationally, and demonstration of this method with real seabird survey data from the Atlantic OCS. The work will proceed in four phases:
Phase 1. Develop draft sampling guidelines (2012)
Phase 2. Calibrate and validate draft sampling guidelines (2012-2013)
Phase 3. Investigate the effects of environmental variability on sampling requirements (2012-2013)
Phase 4. Further refinement of species-specific guidelines and analyses (2013-2016)
A peer-reviewed final report describing the methodology and findings from Phases 1, 2, and 3 of our study was completed and published as a BOEM and NCCOS technical memorandum. Additional related peer-reviewed journal articles and report supplements are linked below. Results have also been presented to managers, stakeholders, and scientists at relevant conferences and workshops.
What We Found
- We have developed a new method to test for hotspots and coldspots of marine bird abundance from survey data
- We can predict the number of samples required to test for hotspots and coldspots in future marine bird surveys
- We have found that certain areas offshore of the U.S. Atlantic coast have been better surveyed than others. Maps of “statistical power” will help renewable energy developers, states, and Federal agencies identify areas where the value of past survey effort can be used to reduce the cost of environmental assessment.
- We generated maps illustrating the results of statistical power analyses (see Digital Supplements F and G to the final report, below):
- Maps of power to detect hotspots and coldspots given available historical survey effort
- Maps of statistically significant hotspots/coldspots of abundance and prevalence given available historical data
- Maps of historical survey effort used to test our methodology
- Maps of average abundance and frequency of occurrence in available historical survey data
Benefits of Our Work
This work will:
- Help plan statistically robust surveys to detect ‘hotspots’ and ‘coldspots’ of seabird abundance and occurrence
- Maximize use of historical survey data in environmental planning decisions, making offshore wind environmental assessment more cost-effective
- Enable identification of sites that are both well-surveyed and that have been found to have relatively low abundance or occurrence of seabird species of concern for offshore renewable energy projects, and for other projects for which seabird impacts may be a concern
- Facilitate environmentally responsible offshore renewable energy siting