State of Nature and climate change

State of Nature, a scientific collaboration of 25 UK conservation organisations, saying that our species are  in already trouble, my thoughts  turned to consider how climate change might be part of that.  Especially when this UK report follows a recent global study, suggesting that more than half of common plants and one third of animals could see a dramatic decline this century due to climate change.

State of Nature is a stock take of our native species – the first of its kind in the UK. It reveals that 60% of the species studied have declined over recent decades. More than one in ten of all the species assessed are under threat of disappearing from our shores altogether. We are losing wildlife at an alarming rate, a continuing historical pattern of loss in the UK going back much further than the 50 years for which we have good information for many species.  Sweeping habitat loss, changes to the ways we manage our countryside, and the more recent impact of climate change, have had a major impact on our wildlife, and they are not going away.

Leafing through the report,  it’s clear that climate change is already affecting UK wildlife in a number of ways, particularly in marine and upland environments.  So it echoes the recent UK Report Card on wildlife and climate change, although of State of Nature presents a much more rounded picture of UK biodiversity, and of the problems it faces.  Changing climate is expected to become an ever more dominant driver of change in the future. Although some species will benefit, the overall impact is likely to be negative. Just how negative depends on how successful we are at reducing global greenhouse gas emissions.  And also upon how well we are able to help nature by adapting to changing conditions. 

First, some good news from the report.  Recent changes to the climate may be benefiting some farmland butterflies such as the ringlet and speckled wood, and southern species in some other taxonomic groups (such as flies) show similar range increases.  Some heathland species, such as Dartford warblers, have been able to move north, despite some of the impacts of habitat loss, fragmentation and deterioration. In woodlands too, species such as speckled wood and silver-washed fritillary butterflies are responding positively to increases in average temperatures. And among our wetlands, dragonflies are expanding northwards and colonising from the continent.

This suggests that those species which find the northern limits of their range within the UK may be able to expand their populations and distributions with a generally warmer climate that we may expect in the future.  Of course, being able to benefit in these ways depends on several other factors - having the right habitat, suitable food and breeding places, and being able to move to expand range.  These essentials may not necessarily be in place, so we’ll often need pro-active nature conservation to be able to reap many of the potential wildlife gains from climate change.

Snippets from the report suggest, however, that the down side  appears to be rather larger.  Already, Arctic char is contracting range in the UK as a result of increasing water temperatures.  Many freshwater habitats are beset by a barrage of threats, and it’s reasonable to expect that these may  be exacerbated by water shortages from drier summers.  

At the coast, sea level rise squeezes habitat into smaller areas in front of fixed coastal defences, and wintering and foraging habitat is often destroyed by static developments.  One in six coastal plant species are declining strongly, including sea barley and slender hare’s-ear; plant communities also deteriorated or been lost completely, particularly those found on coastal dunes and shingle, upper saltmarsh and soft rock cliffs.  Innovative coastal habitat creation and enhancement schemes can use ‘soft’ defences of intertidal habitat to replace uneconomic hard sea walls. These are important, yet small steps in the big picture of our changing coastline.

Of nearly 900 upland species assessed, 65% are declining, with 35% declining strongly.  Birds, butterflies and other invertebrates, and upland plants are all affected.  In the uplands, climate change is nibbling away at both southern and low altitude edges of some species’ ranges.  It’s hard not to conclude that continued warming is likely to corral  upland wildlife into ever smaller areas, of often greatly deteriorated habitat.

Yet it is perhaps in our seas that we’ve seen the greatest impacts of climate change.  Increasing evidence points to climate change affecting the success of UK breeding seabirds, particularly in Scotland.  Changes in the temperature, circulation and salinity of oceans have a marked  impact on the function and structure of marine ecosystems, and the habitats and species within them.  Sea-surface temperatures around the UK have increased in the last 25 years, bringing marked changes to the distribution, abundance and seasonal timing of plankton and fish stocks.  These in turn have brought serious knock-on effects to seabirds, to the extent that some, like the Arctic skua, are on track to be lost as UK breeding species within the next 25 years.

Our urban wildlife cannot escape climate change, either.  Cities and larger towns typically act as urban heat islands, and most UK cities are 1or 2°C warmer than the surrounding countryside.

A groundbreaking report on the worrying status of much British wildlife, State of Nature also contains a timely reminder of what climate change is already starting to bring to the natural world across the UK.  This may not be the main threat today, but with the ongoing escalation of greenhouse gas pollution, it’ll be interesting to see how this affects the findings of future State of Nature reports. You might like to comment with a gaze into the crystal ball!