Climate change impacts on Biodiversity
David Roy
Background
Projected1 responses of species to temperature increases suggests that rapid climate change poses a
serious threat to biodiversity. There is compelling evidence that species are already responding to a
warming climate with ranges expanding polewards2 and shifting uphill3, as well as consistent
advances in species phenologies4. The scientific community and policy makers recognise the need
for the development of indicators of the impacts of climate change on biodiversity5.
The impacts of climate change on biodiversity may be summarised into the following (inter-related)
responses:
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
abundance or geographic distribution of species or the communities which they form
species’ phenology
inter-specific interactions (e.g. feeding relationships)
ecological/evolutionary responses (e.g. behaviour, morphology, physiology)
Existing Indicators
Existing indicators of the impact of climate change on biodiversity have focused on changes in
phenology and distribution/abundance measured by long-term monitoring schemes.
1. Index of the timing of biological spring events in the UK, 1891 to 1947 and 1999 to 2009. A
context indicator within the UK Biodiversity Indicators. The UK Spring Index shows how
changes in climate can lead to changes in the timing of biological events and is calculated
from the annual mean observation date of the following four events: first flowering of
Hawthorn, first flowering of Horse Chestnut, first recorded flight of the Orange Tip Butterfly
and first sight of a Swallow.
2. Impact of climatic change on bird populations. SEBI2010 Indicator 11, published in 20096.
The Climatic Impact Indicator (CII) measures the divergence between the population trends
of bird species projected to expand their range and those predicted to shrink their range due
to climatic change. The indicator is based on a combination of observed population trends
monitored from 122 common bird species in 20 European countries over 26 years, and
projected potential shrinkage or expansion of range size for each of these species at the last
part of this century (2070–2099), derived from climatic envelope models. The ensemble in
this case is the average climate envelope forecast based on six differing future scenarios7.
Related developments
1. Trophic level asynchrony in rates of phenological change. A standardized assessment of 25
532 rates of phenological change for 726 UK terrestrial, freshwater and marine taxa has
revealed differential phenological change among trophic levels, suggesting the potential risk
of temporal mismatch in key trophic interactions8.
Mean trends in phenology over the 30-year period 1976–2005, based on linear mixed effects
models. Secondary consumers have advanced less than primary producers and primary
consumers over the whole period.
2. Changes in Community Temperature Index. Method proposed by DeVictor et al.9. Species
are assigned a Species Temperature Index based on their distributional range (ideally large
scale range, i.e. Europe). STI is the long-term average temperature experienced by
individuals of that species over its range. A Community Temperature Index is calculated as
the average STI values from species within a community (derived from monitoring sites). A
high CTI would reflect a large proportion of ‘warm’ (high STI) species. Warm species
increasing and/or cool species declining can cause a rising CTI. This approach has been
tested using butterfly monitoring schemes in Europe10.
Community Temperature Index (oC)
8,8
8,6
8,4
8,2
1990
1993
1996
1999
2002
2005
References
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Thomas, C. D. et al., Extinction risk from climate change. Nature 427 (6970), 145 (2004).
Hickling, R. et al., The distributions of a wide range of taxonomic groups are expanding
polewards. Global Change Biology 12, 450 (2006).
Wilson, R. J. et al., Changes to the elevational limits and extent of species ranges associated
with climate change (vol 8, pg 1138, 2005). Ecology Letters 8 (12), 1346 (2005); Lenoir, J. et
al., A significant upward shift in plant species optimum elevation during the 20th century.
Science 320 (5884), 1768 (2008).
Parmesan, C., Influences of species, latitudes and methodologies on estimates of
phenological response to global warming. Global Change Biology 13 (9), 1860 (2007).
Mace, G. M. and Baillie, J. E. M., The 2010 biodiversity indicators: Challenges for science and
policy. Conservation Biology 21 (6), 1406 (2007).
Anon, Progress towards the European 2010 biodiversity target. EEA Report No 4/2009. (EEA,
Copenhagen, 2009).
Gregory, R. D. et al., An Indicator of the Impact of Climatic Change on European Bird
Populations. Plos One 4 (3) (2009).
Thackeray, S.J. et al., Trophic level imbalances in rates of phenological change for marine,
freshwater and terrestrial environments. Global Change Biology 16, 3304 (2010).
Devictor, V., Julliard, R., Couvet, D., and Jiguet, F., Birds are tracking climate warming, but
not fast enough. Proceedings of the Royal Society B-Biological Sciences 275 (1652), 2743
(2008).
Van Swaay, C.A.M. et al., The impact of climate change on butterfly communities 1990-2009.
(Butterfly Conservation Europe & De Vlinderstichting, Wageningen, 2010).