Date Published: 10 December 2015
Recent assessment of British wildlife causes concern
A recent study of changes in the diversity of British wildlife over the last 45 years has revealed cause for concern.
Research by scientists at Reading University (Berkshire, England) and the nearby Centre for Ecology & Hydrology (CEH) site in Oxfordshire found that UK native biodiversity has undergone overall continuous decline since the 1970s and that some species groups particularly threatened.
The presence of a wide variety, i.e. 'diversity' of biological species such as plants, fungi and animals (including insects and birds) is important for the overall physical environment that they all inhabit - that is, the 'ecosystem'. Different biological species or groups of species provide different services that are useful to, or even essential for, certain other species. One example is that of insects that pollinate plants in the process of visiting many flowers to collect nectar or pollen. In that case, although the insect is visiting plants to gather food, the plant benefits from the insect moving small particles of pollen between flowers. That can happen due to tiny particles of pollen becoming attached to the insect's legs or body when it visits one flower, falling off the insect while it is visiting other flower. In that way, the insect is, perhaps unknowingly, providing a service to the plant. In general, biological diversity can have many different types of advantages, e.g. for pest control, decomposition of biological material and even climate regulation.
One of the difficulties in studying biodiversity is obtaining sufficient accurate information about the species in an area, such as how many individuals or colonies are present, how they behave and how things change over time. It takes a long time as well as enough expertise to identify species and their behaviours in order to gather enough information, i.e. 'data' to learn about the overall population of the species in an area instead of, for example, just the behaviour of one or a few individual plants or animals. In order to gather scientifically useful data, a person or a group of people must record a lot of observations in the same, i.e. in a consistent, way over a long period of time. An example could be someone keeping a diary noting the dates on which migrating birds such as common house martins arrived and departed from the same building each year, perhaps also noting the number of returning birds, the number of chicks and some information about the weather. Such records might be useful to scientists if lots of people recorded the same information in the same way, all over a long period of time, such as 10, 20 or 30 years. Fortunately many people in the British Isles do keep such systematic records of certain species of wildlife in their local area.
The recent study of changes in the diversity of British wildlife from approx 1970-2010 was only possible due to the time and effort provided by many private individuals who observed and recorded data on a voluntary (unpaid) basis.
Importance of contributions of unpaid 'citizen scientists'
Lead researcher Dr Oliver acknowledged the valuable contributions made by many dedicated volunteers, some of whom have recorded the activities of species or species groups over a long period of time:
" While this new study was carried out with new sophisticated analysis techniques, it was only possible due to the commitment and dedication of trained volunteers associated with natural history recording schemes in Britain.
_ Without these committed and skilled individuals, British scientists and policymakers frankly would be in the dark about the state of our wildlife."
Richard Soulsby, a retired oceanographer who has collected detailed butterfly records in Oxfordshire for the last 20 years, said2:
" It is very rewarding to see that our efforts in recording species over the years has been analysed in such detail, and has helped to produce such important results for understanding the state of British wildlife."
Overall, the data used in the study included millions of records from thousands of trained volunteers who collected information at many different locations across the UK. The data included records about birds, butterflies, moths, various mammals, bees, dragonflies, grasshoppers, ladybirds, (among other insects), as well as plants and mosses. Sources of data included the UK-wide BTO/JNCC/RSPB Breeding Bird Survey (BBS), the UK Butterfly Monitoring Scheme (UKBMS), the Rothamsted Insect Survey and the Joint Nature Conservation Committee (JNCC).
Dr Tom Oliver, the ecologist at Reading University who led the study, said2:
" There have been many efforts to track the changing prospects of wildlife, but this is the biggest and most comprehensive report ever assembled for any country in the world.
_ By standardising records from an army of amateur biologists across the country, we have amassed an impressive array of data, giving us our most complete picture yet of the state of Britain's wildlife.
_ The picture that emerges is of an increasingly fragile system, particularly in species that do vital jobs for humans. Unless efforts are made to reverse some of these declines, we face a future where we will be less confident that we can effectively grow our food."
Just as an indication of the level of detail involved in this study, the researcher's report includes details about:
- 28 species of ants
- 196 species of bees
- 46 species of birds
- 59 species of butterflies
- 304 species of carabid beetles
- 30 species of centipedes
- 31 species of cerambycid beetles
- 67 species of craneflies
- 10 species of crickets and earwigs
- 37 species of dragonflies and damselflies
- 19 species of harvestmen
- 206 species of hoverflies
- 27 species of isopods
- 30 species of ladybird beetles
- 30 species of mammals
- 40 species of millipedes
- 251 species of mosses and liverworts
- 259 species of moths
- 43 species of soldier beetles and glowworms
- 502 species of spiders
- 2,025 species of vascular plants
- 184 species of wasps
In total the scientists used information about 4,424 individual species. It is partly because this research was based on so much information that the conclusions from it should be taken so seriously. That is, not only is it disturbing to note scientists' concerns about diversity trends in British wildlife, but because this work has been based on so much information, people reading about it will understand that it is much more likely to be a true and accurate assessment of the state of British wildlife than if the same conclusions had been drawn from study using a smaller quantity of information.
What did all this data reveal about British wildlife diversity trends ?
When people look at and want to learn from huge amounts of information they often begin by considering which are the best specific questions to ask. For example, one might ask:
- What would we like to find out ?
- What are the 'big questions' that these many small pieces of information might be able to answer if we put them all together?
- Put another way, are there any general trends that the data might the data be able to reveal ?
When there is a clearly stated question or questions, the next thing to do is to decide how best to organize the data so that if it does contain answer(s) to the question(s) asked, then that information is easy to find and to describe to other people.
In this case the researchers were interested in how well the overall ecosystem could continue to function when the number, and so the variety, of different species reduced over time. Put another way, they wanted to know how well the natural environment as a whole continued to thrive when there were fewer different species living in it, i.e. reduced biodiversity.
To learn more about this from the data, the scientists considered the 'functions' of each species and categorized each one by putting it into a 'functional group' according to how that particular species contributed to the overall well being of the ecosystem.
The five functional groupings used in this research were:
- carbon sequestration
- cultural values (with that data presented in two ways, for 'animals only' and for 'plants and animals')
- decomposition
- pest control
- pollination
The researchers used information about the frequency of occurrence of members of the species, e.g. how many hazel dormice (Muscardinus avellanarius), people had recorded seeing, in Britain between 1968-2012 (but mostly 1970-2009) to find out not only which individual species were present in smaller numbers as that time passed, hence were in decline, but also how the functional groupings had fared over time.
Within each of the functional groups, some individual species had increased in numbers while other species had declined. Of the species that increased in numbers, some increased significantly while others increased only slightly. In the same way, of the species that declined over the approx. 40 year period, some declined to a greater extent than others.
In order to decide how well the overall ecosystems could continue to function given the changes in frequencies of occurrence of all the individual species studied during this time, the scientists looked at the proportions of the species of each functional group that declined compared with the proportions of the species of the same functional group that increased. If these proportions were about the same then perhaps the overall ecosystem would continue to function reasonably well despite the loss of some individual species. However, if the species that were increasing did not make-up for those that were decreasing, that might lead to concerns about how that particular function, e.g. pollination, would continue as necessary to support the ecosystem. In the cases of all functional groups, some species experienced highly significant decline during the time period studied, while other species experienced highly significant increase during the same time.
The scientists also looked at other aspects of the data and described their findings in various ways including charts showing the net balance of species trends across ecosystem functions and comparing the numbers of declining species with newly arriving species categorized in the same functional groupings. Full details can be found in the research paper itself (ref. at the end of this article).
What does this mean for British wildlife ?
Overall, analysis of the data considered in this study revealed significant differences in biodiversity trends between the five functional groups. The greatest highly significant declines in proportions of species were in the pollination and cultural values (animals only) functional groupings. However, those groups also had the highest proportions of highly significant increases in proportions of species.
The data revealed some declines in species across all the functional groups. However, the scientists explained that even in the cases of the functional groups that had experienced net declines of species over the approx. 40 year time period, such as the pollination and pest control groups, that might not necessarily have led to lower or less efficient supply of those functions (services) within the ecosystem. Even so, they expressed concern about erosion of the resilience, i.e. ability to continue to operate well in case of possible adverse circumstances in the future, of some functions of the ecosystem. One reason for this is that if a function of an ecosystem relies on the activity of a smaller number of species then the consequences of decline of any one of those individual species is more serious than if that function of the ecosystem was supplied by a much large bumber and range of species.
The researchers described and explained their findings in considerable detail, also indicating areas in which current knowledge is lacking and further work suggested.
One striking aspect of this research is the immense complexity involved in using a huge quantity of detailed information (observations of specific species at specific times and places) to draw accurate and useful general conclusions about just five or six functions of the ecosystem as a whole. Extracting just a few simple 'conclusions' from the report of this scientific analysis risks diminishing the extent and importance of the study by over-simplifucation. In the 'Discussion' section of the paper, the authors state that:
" With regards to the five ecosystem functions that we considered, our overall results suggest that widespread concerns that biodiversity declines will compromise ecosystem functions and the services they underpin are well founded, but our results suggest that certain functions are less resilient and at higher risk than others."
Dr. Tom Oliver et.al. in Declining resilience of ecosystem functions under biodiversity loss
Although Reading University's news item about this study begins with the alarming statement that "British wildlife is at its most perilous state ever recorded in the past 40 years", the published paper indicates that there is hope.
Prof James Bullock, co-author of this study, commented2 that:
" While this analysis sends us a warning, concerted conservation efforts may allow us to halt these declines.
_ Conservation actions, such as wildlife-friendly farming, can avoid the loss of biodiversity and the resulting erosion of the pollination, pest control and other benefits we derive from nature."
It is thanks to the valuable contributions of numerous volunteer observers recording information, data analysis and interpretation by professional scientists, and the influence of mass and social media, that the population at large can be encouraged to appreciate and protect the ecosystem as a whole as well as the many much-loved species within it.
Sources include 1nature.com and 2reading.ac.uk
