New statistical methods result in better marine environmental monitoring and impact assessment
Submitting Institution
University of St AndrewsUnit of Assessment
Mathematical SciencesSummary Impact Type
EnvironmentalResearch Subject Area(s)
Mathematical Sciences: Statistics
Summary of the impact
Researchers at the University of St Andrews have changed the way
environmental monitoring and impact assessment data are collected and
analysed, particularly in the marine environment. We have developed new
statistical models of wildlife population dynamics that, for example, form
the basis for population assessment of most of the world's grey seals,
allowing the UK and Canadian governments to implement effective management
of the populations. Other research carried out by us has led to
reformulation of the recommended standard statistical practice for impact
assessment in the UK marine renewables industry, enabling marine
regulators such as Marine Scotland to make better-informed licensing
decisions concerning large-scale offshore renewable energy developments.
Underpinning research
At the University of St Andrews, the Centre for Research into Ecological
and Environmental Modelling (CREEM) has been at the forefront of
developing realistic "hidden process models" for animal population
dynamics, which allow the major sources of uncertainty to be incorporated
in inference (e.g.1,2,3). Work in this area started in 1993,
when Prof ST Buckland was appointed. This resulted in deer management
models, developed in collaboration with BioSS and the Macaulay Land Use
Research Inst (now the James Hutton Inst), used to guide Scottish deer
managers on culling levels. Dr KB Newman (Senior Lecturer, 2001-06, now US
Fish and Wildlife Service) brought considerable expertise in this field,
and at the same time, Dr L Thomas (Reader, appointed 1997) first became
involved in modelling the dynamics of grey seal populations in work
commissioned by Defra.
Prior to our work, realistic population models could be built, but not
fitted to data in a rigorous manner; alternatively, models could be fitted
to data, but they were necessarily too simple to be realistic. Our
framework allows multiple diverse sources of information to be
incorporated in a consistent manner, including expert opinion, which is
vital when management decisions must be made about species for which
little concrete information exists. The models (largely) use Bayesian
inference; we have developed fitting methods based on Markov chain Monte
Carlo3 and on particle filtering1,2, and have
compared the two2. Key challenges that have been overcome,
after the initial framework was developed, include developing general but
reasonably fast fitting algorithms, extensions to allow model selection,
and incorporating animal dispersal.
Since 2008, we have built a team to develop improved methods for
assessing marine environmental impact. The key people in the team are Dr
ML Mackenzie (Lecturer, appointed 2003), Dr EA Rexstad (Research Fellow,
appointed 2005), Buckland and Thomas.
Assessment of environmental impact at marine renewable sites involves the
analysis of survey data to look for evidence of either overall declines or
redistribution of animals in the area (or both). Therefore, reliable
quantification of any environmental impacts requires statistically-sound
surface-fitting methods that accurately describe both the temporal
magnitude and spatial range of impacts. Challenges include the requirement
to account for missed animals during the surveying, small sample size,
poor survey design, and the fact that sites designated for marine
renewables (such as undersea turbines and wind farms) often have complex
topography with abrupt local changes in animal density. Motivated by this
and other applications, a research group led by Mackenzie developed during
the REF period spatial smoothing methods4 that respect complex
study region boundaries, being based on geodesic ("as the animal swims")
distance between points, rather than Euclidean distances. These methods
allow the amount of smoothing to vary spatially, making them more flexible
than standard approaches.
Until recently, the only reliable approach for collecting environmental
impact assessment data was a visual shipboard or aerial survey along
random transect lines — both of which are expensive to undertake. We have
evaluated the use of digital survey methods, in which high-resolution
digital images are obtained from aircraft flying at higher altitude than
is possible for visual surveys. These methods are now replacing visual
survey methods for seabirds affected by offshore wind farm developments5.
We have also explored the potential contribution of passive acoustics in
these sites6, which offer greater cost-effectiveness. This work
has been led by Buckland and Thomas.
References to the research
1Buckland, S.T., Newman, K.B., Fernández, C., Thomas, L. and
Harwood, J. 2007. Embedding population dynamics models in inference. Statistical
Science 22, 44-58. DOI: 10.1214/088342306000000673.
This output was submitted to RAE2008 under UoA22, for which the unit
scored 2.65 overall for publications, with 95% of outputs scored at 2* or
greater.
2Newman, K.B., Fernández, C., Thomas, L. and Buckland, S.T.
2009. Monte Carlo inference for state-space models of wild animal
populations. Biometrics 65, 572-583. DOI: 10.1111/j.1541-0420.2008.01073.x
3King, R., Morgan, B.J.T., Gimenez, O. and Brooks, S.P. 2010.
Bayesian Analysis for Population Ecology. CRC Press, Boca Raton.
ISBN: 9781439811870. Available from the University library.
4Scott Hayward, L.A.S., MacKenzie, M.L., Donovan, C.R.,
Walker, C.G. and Ashe, E. 2013. Complex Region Spatial Smoother (CReSS).
Journal of Computational and Graphical Statistics. DOI: 10.1080/10618600.2012.762920.
Posted online 23 Jan 2013.
5Buckland, S.T., Burt, M.L., Rexstad, E.A., Mellor, M.,
Williams, A.E. and Woodward, R. 2012. Aerial surveys of seabirds: the
advent of digital methods. J. App. Ecol., 49, 960-967.
DOI: 10.1111/j.1365-2664.2012.02150.x.
6Marques, T.A, L. Thomas, S.W. Martin, D.K. Mellinger, J.A.
Ward, D.J. Moretti, D. Harris and P.L. Tyack. 2013. Estimating animal
population density using passive acoustics. Biological Reviews 88,
287-309. DOI: 10.1111/brv.12001.
Outputs 2, 3 and 4 best indicate the quality of the research.
Details of the impact
Population dynamics modelling
Our framework for modelling wildlife population dynamics, as detailed in
section 2, has been applied to inform a range of real-world management
scenarios involving multi-million pound industries, including red deer
(UK), pacific salmon (USA) and the red grouse-hen harrier system (UK).
Buckland was invited to participate in a Royal Society of Edinburgh
inquiry into the future of the Scottish fishing industry; the resulting
report[S3] made a number of recommendations, several of which
have since been implemented. However, we focus on applications to grey
seals, where our methods form the basis for management of most of the
world's populations. In the UK, grey seals are a controversial
conservation success story: they were the first mammal given statutory
protection (in 1914) following historical over-harvesting; numbers have
increased substantially and now support a large eco-tourism industry, but
this has also brought conflict with both the fishing and the fish-farming
industries. Management is led by an independent panel of scientists
convened by NERC, the Special Committee on Seals. They meet annually and
provide management recommendations, as well as answering specific
questions posed by UK and Scottish government[S4]. Estimates of
population size, trajectory and other management-relevant parameters come
from a population dynamics model developed within CREEM, updated annually
(including throughout 2008-2013) with new survey information. The other
globally significant population occurs in Eastern Canada; there the
methods developed for UK seals were adapted by members of CREEM to fit the
different population dynamics and survey methods. These methods are used
by the management agency (Canadian Department of Fisheries and Oceans) for
population assessment, and also to determine sustainable levels of
harvest, should a commercial harvest for this species be re-started.[S5]
The Deputy Chief Scientific Adviser and Head of Marine Evidence at Defra
writes: "Under the 1970 Conservation of Seals Act, the Natural Environment
Research Council has a statutory obligation to provide the UK government
with `...scientific advice on matters related to the management of seal
populations'. This advice is provided annually by a panel of experts — the
Special Committee on Seals. A major component of the advice is up-to-date
information on the size and distribution of UK seal populations —
information provided each year by the University of St Andrews Sea Mammal
Research Unit in collaboration with CREEM. The Bayesian state-space
modelling methods developed by CREEM ... are instrumental in providing an
estimate of total population size from annual survey data. They represent
the state-of-the art in the field ... Outputs from the models are viewed
with confidence by all stakeholders and in our view are a unique and
integral component of the advice to the Scottish Executive Environment and
Rural Affairs Department (SEERAD) and the Department for Environment Food
and Rural Affairs (Defra). Overall the advanced population dynamics
modelling methods developed at CREEM have made a very considerable
contribution to Defra's ability to determine the population status of UK
grey seal populations, and to quantify uncertainty in these
determinations. This has, in turn, contributed to assessing `Favourable
Conservation Status' for important seal populations — an EU requirement
under the Habitats Directive." [S1]
State-space models are being used with increasing frequency to
characterise the population dynamics of salmon, delta smelt, and other
fish species in the western United States, and to provide guidance for
assessing the effects of management actions. Methods developed at St
Andrews have allowed more realistic, and hence more reliable, modelling to
be conducted. The US Fish and Wildlife Service used our methods in
2008-2010 to develop improved life cycle models for Chinook salmon, and to
assess the effects of management actions (particularly the effects of
water exports, and reductions in these exports) on delta smelt populations[S6].
Monitoring the impact of renewable energy developments
Our spatial modelling (and associated) methods have had particular impact
within the marine renewables industry. Offshore wind, tidal and wave
energy is intended to produce 20% of UK electricity by 2020. However, the
development and operation of energy installations has the potential to
impact wild animal populations in the area, and developers are required to
conduct environmental assessments as part of the permitting process, as
well as ongoing monitoring. We have formulated UK-wide acceptable practice
for survey design and analysis in this area based on work commissioned by
Marine Scotland. We have also advised government regulators, advisory
bodies, energy development companies and environmental consultants. We
delivered a half-day workshop to representatives of the windfarm industry
in London in November 2010, developed an EPSRC-funded 4-day workshop on
impact assessment in offshore renewable energy development in June 2011,
attended by 33 individuals, and offered a training workshop in St Andrews
in September 2013, attended by 30 individuals. Attendees represent
regulators (e.g. Marine Scotland, JNCC, SNH), conservation bodies (e.g.
RSPB, BTO), consultancy companies and power companies.
The influence of our work on decisions of whether to license offshore
renewable energy developments is indicated in a letter from the Marine
Renewable Energy Programme Manager at Marine Scotland (Scottish Government
body), which states[S2]: `We scrutinise licence applications
for evidence that energy developers ... have provided robust estimates of
abundance of seabirds and/or cetaceans. Marine Scotland commissioned CREEM
to provide a guidance document on best practice for the design and
analysis of baseline surveys of the distributions of birds and mammals and
subsequent environmental impact assessments ... of marine renewable energy
developments. As a result, CREEM-based research outputs now form a central
part of the recommended statistical analysis for impact assessment in the
Scottish marine renewables sector.... We consider that the CREEM group is
an authoritative source of advice on marine survey and data analysis in
support of renewable energy developments .... Robust data analysis is
providing sound foundations for both licensing decisions and for the
definition of impact monitoring programmes.'
Two UK companies use methods, developed in collaboration with us during
2008-2010, for surveying seabirds using high-resolution imagery: HiDef
(who use high-resolution video) and APEM (who use high-resolution stills).
Both companies now routinely use the methods to quantify seabird abundance
in areas proposed for large-scale offshore wind farms. Thaxter and Burton[S7]
report on the Carmarthen Bay study, designed and analysed by us, and in
which both companies participated, together with WWT Consulting, to
compare and evaluate different survey methodologies.
Sources to corroborate the impact
[S1]Letter on file from the Deputy Chief Scientific Adviser to
Defra.
[S2]Letter on file from the Marine Renewable Energy Programme
Manager at Marine Scotland.
[S3]RSE press release. 2014. Independent inquiry makes key
recommendations for the sustainable future of the Scottish fishing
industry. See
http://www.royalsoced.org.uk/134_IndependentInquirymakeskeyrecommendationsfortheSustainableFutureoftheScottishFishingIndustry.html
This press release clarifies the importance of the inquiry
recommendations for the future of the Scottish Fishing industry.
[S4]Special Committee on Seals. 2012. Scientific advice on
matters related to the management of seal populations: 2012. See http://www.scotland.gov.uk/Topics/marine/marine-
environment/species/19887/20814/22139 for information on SCOS and
http://www.smru.st-andrews.ac.uk/documents/1199.pdf for the 2012 report.
Confirms contribution of our modelling in shaping advice to the UK and
Scottish governments.
[S5]Department of Fisheries and Oceans. 2011. Stock assessment
of Northwest Atlantic grey seals (Halichoerus grypus). DFO Can.
Sci. Advis. Sec. Sci. Advis. Rep. 2010/091. See
http://www.dfo-mpo.gc.ca/CSAS/Csas/publications/sar-as/2010/2010_091_e.pdf
Confirms contribution of our modelling in shaping advice to the Canadian
government.
[S6]Maunder, M.N., and Deriso, R.B. 2011. A state-space
multistage life cycle model to evaluate population impacts in the presence
of density dependence: illustrated with application to delta smelt. Can.
J. Fish. Aquat. Sci. 068, 1285-1306. DOI: 10.1139/F2011-071.
Confirms use of our methods for assessing delta smout populations in
California.
[S7]Thaxter, C.B. and Burton, N.H.K. 2009. High Definition
Imagery for Surveying Seabirds and Marine Mammals: A Review of Recent
Trials and Development of Protocols. COWRIE/BTO report, available at
http://www.coastalkent.net/data/news/downloads/COWRIE%20High%20Definition%20Imagery%20
Final%20Report%2020091130.pdf.
Confirms our input to methods adopted by HiDef and APEM.