Rationale

In this chapter

Introduction Curiosity and necessity
Pre-existing published advice Its effective application
Motivation A cursory review of legislation
Objective Policy and the threshold of "reasonable
likelihood" ('more-likely-than-not')
Proportionality Balance; ensuring the ends justify the means

1.1 Introduction

There is more than one reason for reading this book, but all reasons can be divided into two broad camps:

» Curiosity.

» Necessity.

If you have opened this book because you are curious, then you know your level of motivation and what you hope to gain from the exercise.

If you have opened this book out of necessity, it is possible you do not want to read it and may not be motivated at all.

The irony is that those of you reading out of curiosity may read this chapter or not as you choose, but those of you reading out of necessity, even if you have little or no motivation, must read this chapter.

Let there be no misunderstanding: every tree is contentious and a woodland is an anvil waiting to fall Looney-Tunes-style upon the career of the unwary.

There is always public opposition to any operation that may fell trees. If you are assessing an area of woodland in support of a development proposal, you may well find yourself in the local paper. If you are assessing Ancient Semi-Natural Woodland in support of a development proposal, it is well within the bounds of probability that you will end up facing a Public Inquiry and national infamy, so you would be wise to ensure your appraisal is robust, because the opposition may bring in a hired-gun to try and shoot it full of holes.

In the recent past it has been common practice for appraisals of wooded habitat to defer to published guidance, in an (entirely understandable) attempt to guard against the possibility that a client might fall foul of conservation legislation, and to avoid any challenge from a third-party (such as a Local Authority Ecologist).

1.2 Pre-existing published advice

At the time of writing (2018), there are currently two publications that deal with roost surveys in wooded habitat:

» British Standards Institute 2015. BS 8956 – Surveying for bats in trees and woodland. BSI London; and

» Collins J. (ed.) 2016. Bat Surveys for Professional Ecologists – Good Practice Guidelines. London: Bat Conservation Trust.

Both include sensible advice and both have an entirely honourable foundation. Nevertheless, this book will not refer to either of these guidance documents again following this chapter. The reason for this is that routine deference to published guidance (without having reviewed the differences between each individual species, and thereon tailored the actions advocated to the most effective equipment, method, timing and effort in the context of a specific project) dulls the edge of the surveyor. To a certain extent, it also denies the surveyor the satisfaction of designing the survey, and ultimately the joy of performing it.

Thankfully, the authors of both guidance texts were sufficiently experienced as to anticipate this, and both allow for creative input in the design of appraisals.

The British Standard opens with this statement:

"As a guide, this British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification or a code of practice and claims of compliance cannot be made to it."

This is also the spirit of text within subsection 1.1.3 of Bat Conservation Trust's Good Practice Guidelines, which states:

"The guidelines should be interpreted and adapted on a case-by-case basis according to site-specific factors and the professional judgement of an experienced ecologist. Where examples are used in the guidelines they are descriptive rather than prescriptive."

Furthermore:

"It is accepted that departures from the guidelines (e.g. either increasing or decreasing the number of surveys carried out or using alternative methods) are often appropriate. However, in this scenario an ecologist should provide documentary evidence of (a) their expertise in making this judgement and (b) the ecological rationale behind the judgement."

In this context 'descriptive rather than prescriptive' might be taken to mean that the examples are not rules that must be enforced. Nevertheless, although the guidance is not a book of rules, any deviation should be supported by tangible evidence that demonstrates unequivocally the following criteria:

» The circumstances warranted the deviation.

» The method and intensity employed can be proven to be appropriate for the circumstances.

In essence, the requirement is for evidence-supported action, which is both reasonable and sensible. An approach that has been found to satisfy this requirement has been to design the survey and, when the team is satisfied that the design will collect robust data that is justifiably necessary and that can be meaningfully interpreted within a repeatable framework, to compare their design with BS8956 and the guidance produced by Collins (2016) to see how far their design deviates, and why. This ensures the recommendations are supported by evidence to which the reader of any subsequent report will have access, and provides the reader with sufficient information to allow them to perform an independent critical appraisal of the rationale adopted. The process is broadly this:

Step 1 Review the legislation, planning policy and case-law, and any pertinent consultation in order to define an interpretation threshold against which data may be compared.

Step 2 Collate the existing scientific evidence and ensure copies of any texts that were referred to in the survey design are available for third-party review.

Step 3 Gather and collate pre-existing intelligence relating to the site.

Step 4 Review the existing intelligence and conduct a proportionality test to decide whether surveillance is appropriate.

Step 5 If surveillance is appropriate, review the methods available and chose the most effective suite to suit the context of the site and operation proposed (i.e development, management action, etc.).

Step 6 Identify constraints; acknowledge them and mitigate where possible.

Step 7 Define the analysis framework and identify the predicted outcome.

Step 8 Perform the survey.

Step 9 Interpret the results within...