The latest annual update of the UK’s official biodiversity indicators were recently published. In the second of a three-part blog series, Mark Eaton, Principal Conservation Scientist, explains what this year’s update tells us:
In the first blog post, I explained what the indicators are. Now, it's time to talk about what they show.
Overall, this report presents 43 measures of change over the long-term (over the definition of ‘long-term’ varies between measures), and 40 over the short-term. Each measured is assessed as improving, little or no overall change, or deteriorating, with a few said to have insufficient data to enable an assessment to be made.
It should be borne in mind that these are not targets, and an improving measure does not mean that all is well with the variable being measured.
For example, while the bat indicator (C8) shows a welcome increase over both the long-term (since 1999) and short-term (since 2011), there is evidence to suggest that this is a partial recovery from decades of bat decline prior to the start of the indicator period, and bat numbers may still be below previous levels.
In all, 23 of the long-term measures are increasing, 10 deteriorating, and 16 of the short-term assessments are increasing and nine deteriorating. So, on the face of it, is this good news – more going up than down? To be honest, not really – a more nuanced approach is needed to understand what these indicators tell us.
The heart of the matter
To my mind, the most important statistics are those found grouped under CBD strategic goal C, “Improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity”. These state indicators tell us the fundamental details of how the UK’s biodiversity is faring. Regardless of what the other indicators measuring the pressures upon our biodiversity, and the responses being made to help that biodiversity, tell us, if the ‘state’ indicators are bad news then those pressures are too great, and those responses insufficient.
Whilst the aim is for there to ultimately be nine indicators for goal C, only seven are available at present, with those for habitat connectivity and plants of the wider countryside still under development. One of the existing seven indicators, C9: genetic resources for food and agriculture, actually has six measures, five of which are related to populations of livestock rare breeds, the other to the Millennium Seed Bank. If you consider that each C9 measure has both a long- and short-term assessment, which means that 12 of the total of 83 assessments published last week are from this indicator alone.
Of these, nine are increasing, which of course good news and speaks of good progress towards Aichi target 13, relating to the genetic diversity of cultivated plants and farmed/domesticated animals. But there’ll be no dancing in the streets of Sandy for that, as trends in Toggenburg goats and Gloucestershire Old Spot pigs have no relation to what is happening to the UK’s nature.
This also highlights the irrelevance of the headline statistics of the overall proportion of the measures in the three (increasing/little or no change/deteriorating) categories, as the number of measures for each subject area varies considerably – there’s far too much prominence for livestock trends, in my opinion.
The nine increasing measures for indicator C9 represent nearly a quarter of all the positive assessments in this year’s report!
Rather, if we focus on the key measures of how the UK’s nature is doing, we see that the indicator for farmland birds is less than half its 1970 starting value, and has continued to decline in the short term, the woodland bird indicator is down by 23% since 1970, although stable in the short-term, and although the seabird indicator was not updated or formally assessed in 2018 due to technical reasons, it is clearly in decline, down by 21% in 30 years.
Whilst the wintering waterbird indicator is still well above its 1975 start point courtesy of a fantastic rise through the 1970s, 80s and 90s, that too is now in a downward slide, reaching its lowest level for over 25 years. Only the indicator of breeding waterbirds has shown stability, and even that has a worrying hint of a downturn.
Other species groups are also struggling - the index of habitat specialist butterflies has fallen by a staggering 77% since 1976, and that for those of the wider countryside by 46% over the same period. An indicator of the status of priority species, which reports on trends in species identified as a conservation priority by the statutory conservation agencies of any of the UK’s four nations, shows ongoing declines in abundance although the indicator showing trends in occurrence has remained stable.
Come back tomorrow for the final part, where, despite the declines, I ask if there is any hope.