Animal adaptations ‘not keeping pace with climate change’
International study highlights impact on phenology. Nick Carne reports.
The world’s climate is changing at a pace that is leaving some animal species unable to adapt quickly enough, according to an international team of 64 researchers.
Their meta-analysis focussing on birds, published in the journal Nature Communications, shows that the historical phenology of these species – the timing of life cycle events such as breeding and migration – is mismatched to current climate.
Species can potentially respond by altering their phenology, they say, but only if there is sufficient genetic variation or plasticity in their behaviour and development.
Changes in body size, body mass or other morphological traits that also have been associated with climate change show no systematic pattern, they add.
The research was led by Viktoriia Radchuk, Alexandre Courtiol and Stephanie Kramer-Schadt from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Germany.
With colleagues from 19 countries, they reviewed 10,090 scientific abstracts and extracted data from 71 published studies (covering 17 species in 13 countries), seeking information relating changes in climate to possible changes in phenological and morphological traits.
Next, they evaluated whether observed trait changes were associated with higher survival or an increased number of offspring.
"We demonstrate that in temperate regions, the rising temperatures are associated with the shift of the timing of biological events to earlier dates," Radchuk says.
Co-author Thomas Reed, from University College Cork, Ireland, notes that the results were obtained by comparing the observed response to climate change “with the one expected if a population would be able to adjust their traits so to track the climate change perfectly".
It is particularly worrisome, the researchers say, that the data covered predominantly common and abundant species such as the great tit (Parus major), the European pied flycatcher (Ficedula hypoleuca) or the common magpie (Pica pica), which are known to cope with climate change relatively well.
"Adaptive responses among rare or endangered species remain to be analysed. We fear that the forecasts of population persistence for such species of conservation concern will be even more pessimistic," says Kramer-Schadt.
The researchers say that to date most global multi-species studies assessing animal responses to climate change have focused primarily on changes in distribution ranges, and models commonly used to predict distributions and population viability under climate change usually do not incorporate the potential for species to adapt.
“Our results are an important first demonstration that, at least in a range of bird species, adaptive phenological responses may partially alleviate negative fitness effects of changing climate,” they write in their paper.
“Further work is needed to quantify the extent of such buffering and to broaden the taxonomic scope to determine if this conclusion also applies to species already encountering higher extinction risk for reasons unrelated to climate.”