New research links tree health to how birds respond to climate change


Date:
September 28, 2021
Source:
University of Oxford
Summary:
New research has revealed that shifts in the timing of egg laying
by great tits in response to climate change vary markedly between
breeding sites within the same woodland and that this variation
is linked to the health of nearby oak trees.



FULL STORY ==========================================================================
New Research from Oxford University has revealed that shifts in the
timing of egg laying by great tits in response to climate change vary
markedly between breeding sites within the same woodland and that this variation is linked to the health of nearby oak trees.


========================================================================== Great tits in the UK lay their eggs around 14 days earlier than they
did in the 1960's. As a result, these songbirds are keeping pace with
the other members of their food chain -- winter moth caterpillars and
the oak trees on which these insects feed -- which have also advanced
their spring timing in response to climate change over recent years.

'Much of our understanding of how animals respond to climate change
comes from studies that assume all individuals within a population
experience the same environment. However, we know this isn't the case, particularly for animals that are limited in how far they can travel
from dependent offspring.

Neighbouring individuals may experience very different
environments. Studying these differences helps us understand what might
limit the ability of animals to adjust to changing environments and
therefore the scope for populations to cope with climate change.' Said
Dr Ella Cole, who co-led the research.

The new study from the Department of Zoology, Oxford University, has
revealed marked spatial variation in the extent to which great tits are adjusting their timing of egg laying within a single woodland. Analysis
of breeding events from over 13,000 great tits over a 60-year timespan
showed that the slowest nesting sites have only advanced by 7.5 days,
whilst the fastest sites advanced by 25.6 days.

This variation is linked to the health of the oak trees nearby the
nesting site. The healthier the oak trees around the nest, the larger
the advancement in timing a laying. Birds breeding in areas with healthy
oaks advanced their laying by 5.4 days more than those breeding in areas
with unhealthy oaks.

The findings, published in the journal Nature Climate Change, demonstrate
how examining responses to climate change at small spatial scales reveal patterns and relationships that are masked by population wide studies.

The research, which was carried out at Oxford University's Wytham Woods,
used breeding data from 964 fixed-location nest boxes, together with information on the health of 5,748 mature oak trees.

'Oak trees are extremely important to tits during the spring because
of the huge numbers of caterpillars that feed on their foliage. We know
from previous research that great tits nesting in territories containing
lots of oak trees begin laying earlier and are more successful breeders.'
'Our findings suggest that birds nesting in areas with poorer oak health
are less able to keep up with the advancement of spring. This could
be because they are unable to find the resources they need to start
breeding or because declines in oak health affect the cues birds use to
time breeding.' Added Dr Regan, who also co-led the work.

This work suggests that studying response to climate change at a scale
that is relevant to individual animals can provide new insights in this
field. The researchers hope that the findings will promote more studies
that explore the causes and consequences of small-scale variation in
response to climate change.

========================================================================== Story Source: Materials provided by University_of_Oxford. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Ella F. Cole, Charlotte E. Regan, Ben C. Sheldon. Spatial
variation in
avian phenological response to climate change linked to tree health.

Nature Climate Change, 2021; DOI: 10.1038/s41558-021-01140-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210928102229.htm

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