How does climate change affect birds?
Research staff from the UPV and the UV assess the impact of climate change on the productivity of the common reed warbler and the moustached warbler
UNIVERSITAT POLITÈCNICA DE VALÈNCIA
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THE TWO SPECIES STUDIED WERE THE MOUSTACHED WARBLER (ACROCEPHALUS MELANOPOGON) AND THE COMMON REED WARBLER (ACROCEPHALUS SCIRPACEUS), BOTH ASSOCIATED WITH WETLANDS ON THE MEDITERRANEAN COAST.
view moreCREDIT: UPV
The work, published in the Bird Study scientific journal, is part of the PhD thesis that Pau Lucio, Associate Lecturer in the Animal Science Department at the Gandia Campus, is developing between the UPV and the Cavanilles Institute of Biodiversity and Evolutionary Biology of the University of Valencia.
The two species studied were the moustached warbler (Acrocephalus melanopogon) and the common reed warbler (Acrocephalus scirpaceus), both associated with wetlands on the Mediterranean coast.
The moustached warbler is a resident/short-distance migrant listed as "vulnerable" in the Spanish Red Data Book of Birds 2021 due to its population decline in recent years. Spain is home to the largest population of this species in Western Europe.
In contrast, the common reed warbler, more generalist in its habitat preferences, is a long-distance migrant (it visits Spanish wetlands during the breeding season and spends the winter in Africa). Its conservation status is defined as of "least concern", as it is widely distributed throughout Europe.
Scientific ringing
According to Pau Lucio, the research has aimed to understand to what extent different climatic and/or geographical factors are affecting productivity, i.e. the relationship between the number born in a given year and the number of adults of both species, using a large database with 25 years of ringing in Spanish wetlands. "Specifically, we have used data from the scientific ringing programme for the monitoring of breeding bird species in Spain (PASER) between 1995 and 2021", adds Pau Lucio.
Effect of extreme weather events
The study concludes that a cumulative rainfall of up to approximately 100 mm favours the productivity of the moustached warbler, and rainfall above this threshold is detrimental to the reproduction of the species. As for temperatures, the UPV and UV team observed that high values have a negative effect.
In contrast, temperature positively affected common reed warbler productivity, while rainfall had almost no effect. However, productivity also peaked when rainfall was close to 100 mm.
"Warmer temperatures and more frequent heavy rainfall may compromise the conservation of the moustached warbler in Spain due to the adverse effect of both elements on its productivity. In contrast, higher temperatures may benefit the common reed warbler," says Virginia Garófano from the Research Institute for Integrated Coastal Zone Management (IGIC) of the UPV Gandia Campus.
Thus, the study concludes that, given the current climate emergency, it is likely that the population of the moustached warbler will decrease while the population of the common reed warbler could increase. However, further work is needed to establish the specific impact of climate change on survival and its implications for the population trends and dynamics of these two species.
Climate-sensitive periods
One of the main advances of this work has been to be able to use a large database with a large spatial and temporal distribution and also to investigate the specific period (time window) in which climate variables have the most significant impact on productivity to define climatically sensitive periods taking into account spatial variables (site, longitude, latitude and elevation) and temporal changes (year).
"This advance in the ecological modelling of trends in bird populations has been possible thanks to the use of complex data modelling techniques such as data mining, machine learning techniques and the use of genetic algorithms in the optimisation of the models," says Rafael Muñoz-Mas, researcher also linked to the IGIC of the UPV and co-author of the study.
JOURNAL
Bird Study
METHOD OF RESEARCH
Meta-analysis
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Unravelling the link between productivity and climate for two sympatric Acrocephalus warblers across Spain
Exploring bird breeding behaviour and microbiomes in the radioactive Chornobyl Exclusion Zone
New research finds surprising differences in the diets and gut microbiomes of songbirds living in the radiation contaminated areas of the Chornobyl Exclusion Zone, Ukraine. This study is also the first to examine the breeding behaviour and early life of birds growing up in radiologically contaminated habitats.
The Chornobyl Exclusion Zone (Ukrainian), also known as the Chernobyl Exclusion Zone (Russian), is an area of approximately 2,600 km2 of radiologically contaminated land that surrounds the Chornobyl Nuclear Power Plant. The levels of contamination are uneven throughout the zone.
“The consequences of radiological contamination to wildlife are still widely unknown, especially the risks posed to wildlife in early life,” says Mr Sameli Piirto, a PhD researcher at the University of Jyväskylä, Finland. “Our hypothesis was that biodiversity in contaminated areas would be compromised leading to changes in birds breeding, diet and gut microbiome.”
To examine the effects of radiological contamination on bird development, Mr Piirto and his team investigated the breeding behaviours and physiologies of two common European songbird species, Great tit (Parus major) and Pied Flycatcher (Ficedula hypoleuca). These were selected due to their well-studied ecologies.
Nest boxes were placed in multiple areas that belonged to two categories within the Chornobyl Exclusion Zone: areas of high radiological contamination and areas of low contamination. The nestling and adult birds that used the nest boxes were then monitored, with DNA from fecal samples being used to study the birds’ diets and characterise their gut microbial communities.
Mr Piirto found that while nest occupancy rate was lower in contaminated areas, there were no other major differences in breeding ecology or nestling health between the two levels of radiation contamination for either species. Surprisingly, both species nestlings were found to actually have a higher diversity of insects in their diet in the contaminated areas.
While environmental radiation levels were not associated with bacterial diversity of the gut microbiome, radiation level was associated with the relative composition of the microbiome. “These results create an interesting background for understanding avian ecology in radiologically contaminated areas,” says Mr Piirto. “They give us valuable novel information on the effects that radiation has on juvenile birds - an area of research that has been unclear until now.”
This research can help to provide insights into the long-term effects of nuclear accidents on wildlife health. “Radiological contamination creates an additional stressor that organisms must cope with, leading to a myriad of consequences that are not yet fully understood,” says Mr Piirto. “Studying the effects of it is crucial if humanity is to pursue an even more nuclear future.”
This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.
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