In this 100th issue
Issue 100 | June 2018
Bulletin of the Chartered
Institute of Ecology
Big Issues: Human Population
Growth and Climate Change
– Beyond Carrying Capacity?
Big Issues: The Hidden
Tragedy of the Earth’s
Big Ideas: Creating
a Mess – The Knepp
In this 100th issue
In this 100th issue
In this 100th issue
53Issue 100 | June 2018
: Do We Need More Evidence-Based
Do We Need More Evidence-Based
Carlos Abrahams MCIEEM Darryn J. Nash CEcol MCIEEM
Keywords: evidence-based, good
practice, guidance, monitoring, survey
As ecologists and
environmental managers, we
rely on good quality baseline
information. However, the
survey methods we currently
employ are often unsupported
by scientiﬁ c testing and are not
proven to provide high quality
outputs. As a community of
practitioners, we should seek
to change this, taking on board
new research and technological
developments – and building
more evidence explicitly into
our survey guidance.
As ecologists and environmental managers,
the data we gather through survey and
monitoring programmes is vitally important
in all aspects of our work. It allows us
to predict impacts with some level of
conﬁ dence, track and anticipate trends
in biodiversity, and assess whether our
management interventions are working
– or not. To generate good quality data
though, we need good quality survey
methods, which are developed, reviewed
and updated in line with existing evidence,
new scientiﬁ c ﬁ ndings and technological
developments (Figure 1).
To an extent, we already have reasonable
survey methods, which have provided
much useful information in national
monitoring programmes or in site-based
assessments. We are lucky in the UK to
have a well-developed history of voluntary
and professional work in the conservation
sector, and long established standards for
surveying ﬂ ora and fauna. However, if we
consider the age of some extant survey
guidance (such as the Great Crested Newt
Figure 1. GPS-enabled tablets allow accurate ﬁ eld recording, with forms that can be
customised to di erent types of survey or sites, to allow standardised data collection.
Photo credit Carlos Abrahams.
Mitigation Guidelines, English Nature
2001), against the pace of research
and technological change, the need for
ongoing updates becomes clear.
We all have a responsibility to ensure that
our survey methods are ﬁ t for purpose.
Both BS:42020 (BSI 2013) and the CIEEM
Code of Professional Conduct require that
methods used to undertake surveys should
follow published good practice guidelines
where they exist. However, if published
guidance is out of date and/or better
techniques have been developed, then we
should take new innovative approaches
where these could provide a better
outcome. To make this type of judgment
call we should be basing our decisions on
evidence of what actually works best for
our particular needs. However, in the ﬁ rst
instance, how much of our established
54 Issue 100 | June 2018
: Do We Need More Evidence-Based
and published good practice guidance is
based on evidence? How frequently has
testing of methods been undertaken,
allowing comparisons between different
survey approaches? And how many of our
methods have been developed for site-
based assessments by professionals, rather
than for national monitoring by citizen
scientists? For example, why do we still
apply the Great Crested Newt Mitigation
Guidelines recommendation of four visits
for presence/absence surveys and six for
population size class assessment (English
Nature 2001) when recent publications
(Kropﬂ i et al. 2010, Sewell et al. 2013)
state that up to six visits may be required
to accurately record presence/absence at
some ponds, and seven to eight surveys are
needed to consistently gauge population
numbers (although the population size class
can probably be determined at the majority
of sites from only four visits, Wynn 2013)?
CIEEM and its contributing members have
done a very useful job in recent years of
compiling the Sources of Survey Methods,
and following this up with A Guide to
Good Practice Guidance, as highlighted by
Sally Hayns in the December 2017 issue of
In Practice (Hayns 2017). Both resources
list a wide range of references, which form
the canon of our professional practice
as ecologists. In January 2016, CIEEM
also produced the excellent Principles of
Preparing Good Guidance for Ecologists
and Environmental Managers. This states
at PRINCIPLE IV that good guidance should
be explicitly based on good evidence:
‘All guidance should be evidence-
based and should reference
original sources, where available,
that illustrate that the techniques
recommended are appropriate……
Where guidance is based on existing
good practice, but the scientiﬁ c
evidence supporting it is limited, this
should be stated and there should be
sufﬁ cient ﬂ exibility in the guidance
to allow for individuals to innovate.
Scientiﬁ c testing, e.g. comparative
studies of different techniques, is
strongly recommended where new
approaches are suggested and the
results should be published widely.’
This principle sets out an aspiration for our
survey guidance that is not being regularly
met in our current documentation. Any
review of guidance drawn from a range of
sources will show that the reasons being
put forward for speciﬁ c recommendations
are often not clear or appropriately justiﬁ ed
even though the actual methods may be
set out in great detail. This omission is
well demonstrated in some of our most
commonly used publications.
Bats: The Bat Conservation Trust’s (BCT)
Bat Surveys for Professional Ecologists
(Collins 2016) is one of the best pieces of
guidance that we have available, and has
been repeatedly updated to its current third
edition. However, some areas remain that
could beneﬁ t from increased explanation
and by reference to the scientiﬁ c literature.
When conducting bat surveys, a critical
ﬁ rst step in determining the level of survey
effort to be employed at a site is a habitat
quality assessment into low, medium
or high categories. This translates into
the number of surveys that should be
undertaken, with 1-3 emergence surveys,
or 3-12 transects being recommended.
Although the guidance for this habitat
assessment process has been improved
in the third edition, it is still limited and
qualitative, with no obvious basis in
evidence. Furthermore, why does the
guidance recommend one visit to low-
potential roost features and three visits to
high-potential features – and why this way
round? Has this approach been tested to
determine whether it will provide accurate
information about roost presence or
absence? If so, it would be very useful to
see the underlying evidence. The inclusion
of background research would serve to
increase conﬁ dence in the method and
would reassure bat surveyors that the
recommendations will provide sound and
valid data. However, the broad rules of
thumb put forward as ‘good practice’ in
the BCT guidance don’t appear to be based
on scientiﬁ c studies that determine how
much survey is appropriate, or how survey
effort should be programmed through
the season. Research that has carried out
method testing should be incorporated
into guidance, and could help to improve
the protocols for assessing building roosts
(Underhill-Day 2017), inform the levels of
survey effort needed to detect common or
rare species at sampling locations (Skalak
et al. 2012), and identify which type of bat
detector we should be using to capture call
data (Figure 2) (Adams et al. 2012).
Birds: There are a number of recognised
survey methods for birds, depending
on the habitats and taxa being targeted
(Gilbert et al. 1998). However, many of
these are designed for national survey
programmes by volunteers, rather than
being optimised for the needs of smaller-
scale site assessments, such as EcIA studies.
A notable exception is the windfarm
survey guidance produced by the statutory
authorities, e.g. Scottish Natural Heritage
(2014). For breeding bird studies, the
majority of consultants will probably use
a territory mapping approach, based
on Common Birds Census (Marchant
Figure 2. Full-spectrum audio recording allows high quality acoustic data to be collected from
vocal species groups, such as bats and birds. Photo credit Carlos Abrahams.
55Issue 100 | June 2018
1983). This method is useful for providing
detailed information on the distribution
of bird territories, but is time-consuming,
and difﬁcult to apply and interpret. As
there is no set number of site visits for
this method when used by consultants,
the number of surveys carried out within
EcIA studies is often determined by the
consultant’s qualitative assessment of the
site or their own established practice. The
appropriate level of survey effort required
to accurately assess the composition and
species-richness of a bird assemblage
in a particular location has not been
determined in many cases (Calladine et
al. 2009). In addition, territory mapping
may not even be the best option for EcIA
purposes: point counts, line transects or
bioacoustic recording might provide equal
or better quality data, and probably with
less survey effort (Figure 3) (Abrahams and
Denny 2018; Gregory et al. 2004).
Reptiles: Our current reptile survey
guidance consists principally of Froglife’s
(1999) ‘Advice Sheet 10: Reptile Surveys’.
There was an attempt to update this
with Natural England’s (2011) Mitigation
Guidelines (TIN102), which were rapidly
withdrawn, and the more recent survey
protocols from Sewell et al. (2013),
which incorporated seasonal variations
in detectability by species. This latter
document was perhaps the ﬁrst major
advance in our approach to reptile survey
in the past two decades, but remains
unknown to many practising ecologists.
The lack of scientiﬁc support for established
methods and the need for improved
approaches was recently highlighted in a
review of reptile monitoring programmes
(Nash 2018), which showed that new
evidence is available to support the revision
of survey protocols (Figure 4).
We need to use science more to tell us
the answers to two important questions:
(i) which survey methods are best – or at
least ‘good’, and (ii) how much survey
effort is needed to generate a sound
understanding of a study area? If we
want to develop robust and accurate
ecological baselines for Environmental
Impact Assessments (and other purposes),
then we should make sure that our
methods are up to the job. It may be that
the methods we currently employ are
just ﬁne, and incorporating referenced
research into our existing guidance would
allow us to demonstrate this. If so, we
have no need for concern. However, if the
methods we use have no demonstrable
scientiﬁc basis then we need to recognise
this as an industry and develop new
protocols over time to promote the best
practicable methods for data collection,
clearly based on evidence. After all, this
is the absolute bedrock of our day-to-day
work, on which we base assessments,
make recommendations and stake our
reputations. How can we not take a more
evidence-based approach to survey?
Creating survey guidance is a hard and
thankless task. Building the content, gaining
agreement from a range of professionals
with their own views and experiences, and
then getting organisations to approve the
ﬁnished article will never be easy. Grifﬁths
et al. (2015) note that ‘The uptake of new
methods by professional practice will.....
be strongly inﬂuenced by cost, practicality
and the explicit requirements of regulatory
authorities’. However, there is always room
for developments in practice where these
are supported by good argument and good
evidence, so each of us as individuals – and
as a community of practitioners – are free
to pave new ways where they are needed.
One could (correctly) argue that professional
judgment should be applied by all ecologists
when designing their surveys, and we
should all be prepared and able to go
beyond standard survey guidance. However,
we don’t always have time to keep up to
date with technical developments in all the
ﬁelds in which we might work. Accessing
information on methodological advances
can be difﬁcult in itself, especially for those
who aren’t fortunate enough to have access
to the scientiﬁc literature.
To help develop a better scientiﬁc context
for our published guidance, there are a
number of ways forward. Firstly, any new
guidance that is produced should explicitly
state the evidence on which it is based,
Figure 3. The use of bioacoustics is common practice for bat surveyors,
but could be used eectively by ecologists studying other groups of
species. Here an acoustic recorder is deployed to record capercaillie
in north-east Scotland. Photo credit Carlos Abrahams.
Figure 4. The use of artiﬁcial cover objects (ACO) has long been the
mainstay of reptile surveys. In the absence of rigorous scientiﬁc testing,
there are still disagreements over the number, material and colour of
ACOs that should be used. Photo credit Carlos Abrahams.
56 Issue 100 | June 2018
Abrahams, C. and Denny, M. (2018). A ﬁ rst test
of unattended, acoustic recorders for monitoring
capercaillie (Tetrao urogallus L.) lekking activity.
Bird Study, in press.
Adams, A.M., Jantzen, M.K., Hamilton, R.M. and
Fenton, M.B. (2012). Do you hear what I hear?
Implications of detector selection for acoustic
monitoring of bats. Methods in Ecology and
Evolution, 3: 992–998.
BSI (2013). BS 42020: Biodiversity — Code of
practice for planning and development. British
Standards Institution, London.
Calladine, J., Garner, G., Wernham, C. and Thiel,
A. (2009). The inﬂ uence of survey frequency on
population estimates of moorland breeding birds.
Bird Study, 56(3): 381-388.
Collins, J. (ed.) (2016). Bat Surveys for Professional
Ecologists: Good Practice Guidelines (3rd edn).
The Bat Conservation Trust, London.
English Nature (2001). Great Crested Newt
Mitigation Guidelines. English Nature, Peterborough.
Froglife (1999). Advice Sheet 10: Reptile Survey.
Gilbert, G., Gibbons, D.W. and Evans, J.
(1998). Bird Monitoring Methods.
Pelagic Publishing Ltd, London.
Gregory R.D., Gibbons D.W. and Donald P.F.
(2004). Bird census and survey techniques.
In: W.J. Sutherland, I. Newton and R.E. Green
(eds), Bird Ecology and Conservation: A Handbook
of Techniques, pp. 17-56. Oxford University
Grifﬁ ths, R.A., Foster, J., W ilkinson, J.W. and
Sewell, D. (2015), Science, statistics and surveys:
a herpetological perspective. Journal of Applied
Ecology, 52: 1413-1417.
Hayns, S. (2017). A Guide to Good Practice
Guidance: A new resource for CIEEM members.
In Practice – Bulletin of the Chartered Institute of
Ecology and Environmental Management, 98: 45.
Kropﬂ i, M., Heer, P. and Pellet, J. (2010). Cost-
effectiveness of two monitoring strategies for
the great crested newt (Triturus cristatus)
Amphibia-Reptilia, 31(3): 403-410.
Marchant, J. (1983). BTO Common Birds Census
instructions. British Trust for Ornithology, Tring.
Nash, D.J. (2018). An assessment of mitigation
translocations for reptiles at development sites.
Unpublished Ph.D. Thesis, University of Kent
Natural England (2011). Technical Information
Note TIN102. Reptile Mitigation Guidelines.
Natural England, Peterborough.
Scottish Natural Heritage (2014). Recommended
bird survey methods to inform impact assessment
of onshore wind farms. Scottish Natural Heritage.
Available at https://www.nature.scot/professional-
Accessed 20 April 2018.
Sewell, D., Grifﬁ ths, R.A., Beebee, T.J.C.,
Foster, J. and Wilkinson, J.W.W. (2013). Survey
protocols for the British herpetofauna Version 1.0.
Skalak, S.L., Sherwin, R.E. and Brigham, R.M.
(2012). Sampling period, size and duration
inﬂ uence measures of bat species richness from
acoustic surveys. Methods in Ecology and
Evolution, 3: 490-502.
Underhill-Day, N. (2017). The Bat Roost Trigger
Index – A New Systematic Approach to Facilitate
Preliminary Bat Roost Assessments. In Practice –
Bulletin of the Chartered Institute of Ecology and
Environmental Management, 96: 37-42. http://
Wynn, J. (2013). Evaluation of survey methods
to determine population-size class for great
crested newts in England and Wales. In Practice –
Bulletin of the Chartered Institute of Ecology and
Environmental Management, 79: 24-25.
Many thanks to Dr Claire Wordley at
Conservation Evidence, Dr Gill Kerby at
CIEEM, and colleagues at Baker
Consultants for comments on an
: Do We Need More Evidence-Based
About the Authors
Carlos Abrahams is
Technical Director at
in Derbyshire and a
Senior Lecturer on the
at Nottingham Trent
University. He has been
an ecology consultant
for 17 years, following earlier work in
countryside management. He has research
interests in drawdown zones, amphibian
ecology and bird bioacoustics.
Contact Carlos at:
Dr Darryn Nash is a
with AECOM based in
Bristol. He has recently
completed his doctorate
at the University of
Kent, where he assessed
was effective in
mitigating reptile-development conﬂ ict.
Contact Darryn at:
and provide appropriate references. Or, if it
is only based on best-guess rules-of-thumb,
this should be stated clearly. Secondly,
consultants, consultees and regulators
should all take a more ﬂ exible approach
to survey methods, and concentrate more
on the quality (and meaning) of outputs
rather than whether standard protocol has
been slavishly followed. Most importantly
though, we would make a call for a ‘Survey
Evidence’ initiative for ecologists, along
similar lines to Conservation Evidence
would gather, assess and disseminate
research ﬁ ndings to allow optimal survey
and monitoring recommendations to be
developed. This could be done within an
organisational setting, or perhaps better,
in a crowd-sourced, Wikipedia-style, online
forum to which anyone interested could
contribute. Such an approach would
allow new research ﬁ ndings to be added
regularly, allowing constant ongoing
development of scientiﬁ cally supported
survey methods and technological
innovations – and rapid communication of
these across the sector, instead of waiting
for irregular approval by a formal authority.
It would be independent, authoritative
and available to all, demonstrating good
practice for our work and enabling us
to make better, informed decisions on
how we gather data. It would require us
to examine our established, and often
outdated, methods. In the end, it would
raise the questions we should all be asking
ourselves. Is our good practice guidance
actually proven to be good enough? And if
not, how can we all make it better?