Specimen collection – one of conservationists’ trickier issues
Conservation can be a contradictory thing at times. Like many people, I first got involved in conservation because of a love of wildlife and wild spaces. Over the years I have been involved in lots of practical conservation activities all over the country and it’s amazing how often those events have seemed to run counter to the ethos of preservation. For every activity of planting or creating habitat, there were half a dozen occasions of cutting down trees and scrub, clearing plants, scything grass… Often the results seemed destructive at first, but over time the longer-term benefits became apparent as biodiversity on the sites flourished. One of the most challenging aspects of conservation work is taking specimens.
OK, so what’s a specimen?
A specimen is a biological sample, where an organism (usually an invertebrate) is collected in the field, preserved and then keyed out under the microscope to identify which species it is. Keying-out is the process used to identify an organism by asking a series of questions about it. A simple example is shown below for identifying female flower bees in the UK:
Often the earlier questions are easily answered in the field but as the key gets into more minute detail these may need examination under a microscope to provide a correct ID.
Taking specimens in this way allows us to see which organisms are present at a site. This gives us lots of information on the habitat quality, that we can benchmark against the country as a whole to see what value we have, and ultimately to enable us to identify sites to try and protect from development.
Wait, hang on, so you’re killing them? Why would you do that? Aren’t you supposed to be conserving wildlife?
This is one of those times when the whole process seems to run against the principles of conservation! The reason for taking specimens is that a large number of invertebrates can’t be identified at a species level from photographs or examination in the field. You will often need to examine microscopic details of, for instance, the insect’s thorax or its genitals (biologists are a strange lot) to determine what you’ve found. One of EWG’s core aims is to identify the biodiversity of the borough and without specimens much of what is out there will not be identifiable.
You mention invertebrates but what about birds and mammals?
Fortunately, in the UK there is no need to take specimens of any vertebrates – all species can be identified in the field with the right photographs or recordings. Many vertebrates are protected and we would be in breach of the law if we collected them.
OK, so it’s just invertebrates then… But why not just leave them alone? Isn’t this just like Victorian butterfly collectors?
The reason biologists need to take specimens is to determine which animals are present in an ecosystem. If we didn’t take specimens most species could never be identified. In the UK the vast majority of biodiversity is invertebrate life, and even if you have no interest in invertebrates in their own right (you really should, they are amazing animals) they form vital food sources for many of our more glamorous animals, as well as being involved in vital ecosystem functions such as pollination, breakdown of waste and recycling of nutrients.
By taking samples we can see which species are expanding their ranges and populations and which are declining; this gives us vital information about the health of our ecosystems. Victorian collectors were often interested in creating private collections for their entertainment; nowadays biologists feed their records into national databases, which other scientists and members of the public can access to see how different species are coping in 21st-century Britain.
Well fine, but I’ve taken pictures of plenty of insects and people have identified them for me. Why not use pictures?
There are many species of invertebrates (especially the larger ones) which can be identified with good pictures or from examination in the field. Where this is possible, there is no need to collect specimens. Unfortunately, a significant number cannot be reliably identified except under lab conditions and this varies from group to group. Most butterflies are identifiable in the field, but there are thousands of species of parasitic wasps in the UK that are impossible to ID this way. The advent of DNA analysis has made things even more complicated as it has revealed the existence of several cryptic species which are visually identical and so need their DNA sampled to determine what they are.
Oh, so you could use DNA then? Couldn’t you do that instead?
The short answer is ‘yes, but’. The use of eDNA (which stands for environmental DNA) to identify which organisms are present in an ecosystem, is a process which has been around since the 80s. It works by taking a sample of soil or water from a site and examining the DNA which is present in it. It does have its limitations, however… All organisms shed DNA all the time, but it degrades very rapidly once it is exposed to the elements so there is a very short window between the DNA being shed and it no longer being useable in the lab. It tends to preserve best in wet and/or cold conditions so this limits the habitats it can be used in.
In addition, the presence of large amounts of DNA from one species can drown out the DNA from less common species – so if you have a dead pigeon upstream of your water sample that is all you may pick up, even if other organisms are present.
Another issue is the biological library of organisms you have to draw on – many species haven’t had their DNA sequenced so we have no data to match. There is a fantastic project called The Darwin Tree of Life which is looking to sequence DNA from 70,000 species found in the UK and Ireland to create genetic barcodes. However, this project is still in its early days.
The final challenge, which is always significant to conservation organisations, is cost. Each analysis costs several hundred pounds so using this across multiple sites quickly becomes extremely expensive.
OK, but I’m still not sure how ethical this is…
Ethics should be at the heart of our conservation decisions. No one goes into conservation because they enjoy this aspect of surveying and it makes a lot of people very uncomfortable for obvious reasons. The alternative though is that we simply don’t know what we have and what we may be losing. It’s impossible to make effective conservation decisions without knowing what pressures our wildlife is under, and the loss of many of these species will have profound impacts on the ecosystem (including potentially for humans) as pollinators or natural pest controllers disappear, or new species spread with global warming.
There is an ethical code of practice that has been built around the collection of specimens to ensure that it is done humanely. Limited numbers of specimens are taken from each site (more insects will die from being hit by the car or bus on the trip to the site than are taken) and there are several studies which have looked at the potential impacts on rare species. These have concluded that these are negligible for short-lived species, as most of our invertebrates are.
Almost all of our invertebrates are extremely prolific and most individuals will be predated at some point in their lifecycle – specimen taking is similar to this natural predation but at a low rate. Their key threats come from land use changes, habitat loss and climate change and we need to understand how these issues are impacting them; their populations can easily withstand limited, responsible collection.
So do EWG collect specimens then?
Actually, at the moment we do not. We don’t have the relevant equipment or resources to undertake proper sampling. We do however collaborate with many organisations as part of our conservation work and some of these will be taking specimens. For example, as part of the surveying of the biodiversity impacts of beavers in Paradise Fields, our partners will be taking samples of particular groups of invertebrates.
We will always ensure that we partner with responsible organisations that match our ethos and values. It will also always be made clear if any volunteering activities involve sampling so that everyone is aware and can make their own decisions on whether they want to attend or not.
We recognise that feelings will always run high on this topic and that there will be many different opinions. But in the spirit of the group, we ask that these opinions are shared and responded to with respect and courtesy, recognising that these come from a place of concern and love for the amazing wildlife of our borough.
Where can I find out more about this topic?
These are some links that you may find useful:
The Code of Conduct for specimen collection can be found on the British Entomological & Natural History Society website:
https://www.benhs.org.uk/resources/collecting/
The Field Studies Council have published a blog on this subject:
More information on the Darwin Tree of Life project can be found here:
Thanks to Alex Worsley for insight into what can be a controversial subject.