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The Effect of Climate Change on Birds
by David Leech |
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7. Future research |
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| There is currently considerable evidence
to suggest that climate change has already affected the abundance,
distributions and population dynamics of a wide range of bird species.
The challenges for the immediate future are: |
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a. |
To understand
more about the way in which climate change might affect different
aspects of bird population dynamics and how such changes may influence
population regulation and viability; and |
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b. |
To understand
more about how climate change may influence the environment and
habitats of birds and how this might affect the ability of birds
to respond to the impacts of climate change. |
| Using long-term data sets such as those collected
by the BTO under the Common Birds Census (CBC), the National Ringing
Scheme and the Nest Record Scheme it is possible to monitor changes
in population sizes, survival rates, breeding success, distribution
and phenology and relate trends observed to variation in a wide range
of climatic variables. Examination of these relationships may help
to predict changes in the ecology of British bird species in relation
to future climatic changes and identify potential threats to their
conservation status in the UK. If available, appropriate conservation
measures can then be taken. |
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| One approach to understanding more about
the way in which changes in the environment might affect the response
of bird species to climate change is demonstrated by the MONARCH (Modelling
Natural Resource Responses to Climate Change) project. The BTO will
use information on dispersal from ringing recoveries to investigate
how well bird populations might be able to track changes in areas
of climatic suitability, as determined from their current distributions.
This work will be carried out in conjunction with studies undertaken
by MONARCH partners, who will be investigating likely changes in the
distribution of habitats. For example, it is possible, that, due to
factors such as soils or water availability, certain habitats may
not spread gradually, but may effectively "jump" from one
area to another, leading to habitat fragmentation. |
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| In addition, as part of MONARCH, the BTO
are investigating the way in which sea-level rise and climate change
will affect wintering shorebirds. Changes in estuary shape, as a result
of sea-level rises will alter sediment characteristics and hence the
suitability of the area for different bird species. Changes will be
reviewed in relation to current plans for sea-defences.The benefits
of managed realignment of coastal sea-defences for the recreation
of habitats, such as salt marsh, that will be lost in areas where
sea-defences do not allow these habitats to retreat inland, must also
be investigated. |
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| Whilst it may not be possible to prevent
all climate-related decreases in the conservation status of individual
species directly, reduction of pressures on British bird populations
due to factors such as habitat loss, decreases in food availability
and persecution, which may be achieved through conservation measures,
could facilitate a more favourable response to climatic change. |
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| Finally, it is important that changes continue
to be monitored and that current long-term data sources continue to
be supported. This is vital for at least three important reasons:
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a. |
We will need
to identify the real impacts of climate change as they develop,
especially as we move out of the range of current norms into newer
and changed climatic regimes.
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b. |
We will need
to evaluate and modify our predictions of the impact of climate
change in the light of new information.
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c. |
We will need
to be able to respond quickly to any unexpected changes that might
occur. For example, there may be thresholds in the response of natural
systems to climate change that are currently unknown. Current predictions
assume that natural systems will respond in a similar manner to
climate changes as they have done in the past. However, it is quite
likely that bird populations might respond quite differently as
the climate becomes warmer. For example, warmer springs might tend
to improve chick survival, until, at a certain point, the increase
in temperature results in drought conditions, causing chick survival
to decline rapidly. |
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| The BTO has recently implemented two new
schemes that may help to increase our understanding of the effects
of climate change on the ecology of bird populations. The Retrapping
Adults for Survival (RAS) project, which started in 1998, aims
to increase the amount of data collected on the survival rates of
bird populations by intensive, long-term monitoring of individual
species over small spatial scales at multiple sites across the UK.
Changes in survival rates may then be related to climatic variables,
such as winter temperatures and rainfall totals. The Migration Watch
project implemented in 2002 will provide a detailed data set concerning
changes in the arrival dates of migratory species at a national scale,
allowing accurate comparison of the timing of migratory movements
between years and permitting identification of the climatic factors
that may influence their advancement |
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