climate change on UAE - Stockholm Environment Institute-US Center

Alternatively, established shrublands retain
ecosystem dominance by using available
water resources, and effectively pool nutrient
resources in small concentrated areas.
Depending on the rainfall regime (evenly
distributed low intensity rainfall or infrequent
high intensity rainstorms), we may expect to
shift the dominance of grasses or shrubs in
the semi-arid drylands of the UAE.
Shifts in phenology: Annual patterns in
the growth, flowering, and fruiting of flora
and foraging, hibernation, and migration of
fauna (all called phenology) are governed
primarily by seasonal resource availability
of light, temperature, and water. In the arid
tropics, it is rare that biota are restricted
by light availability or cool temperatures,
but biotic patterns can often be dependent
on seasonal water availability and excessive
heat. For many desert plants, phenological
cycles are timed to take maximum advantage
of water availability and avoid heat stress.
It is not uncommon to see short, intense
bursts of growth during winter or spring rainy
periods, plants distributing seeds or flowers
immediately following the period of growth,
and near or complete senescence by the onset
of intense summer heat. One of the expected
impacts of <strong>climate</strong> <strong>change</strong> throughout
a wide range of biomes will be shifts in
phenological cycles. In the UAE, these shifts
may materialize in the form of either earlier
or delayed spring growth periods as elastic
plants adapt to <strong>change</strong>s in precipitation
patterns. Amongst phenological researchers,
there is significant concern that these
<strong>change</strong>s in seasonal patterns may disrupt
critical synchrony between co-dependent
biota (Morisette et al., 2008). For example, as
the date of spring has advanced throughout
the northern hemisphere due to warmer
temperatures (Schwartz and Reiter, 2000),
the annual abundance of insects which rely on
early vegetation growth has correspondingly
advanced as well. However, migratory birds
which feed on these insects do not breed
earlier, and correspondingly, population
abundances have fallen in some species
(Visser et al., 1998). There is a significant risk
that interdependent biota, particularly in
the highly precipitation dependent UAE, will
loose synchrony, impacting both local and
migratory species.
8.3. Examples of <strong>climate</strong> <strong>change</strong>
induced biodiversity
thresholds in the UAE
There are significant uncertainties in predicting
precipitation volumes and patterns with <strong>climate</strong>
<strong>change</strong> in the Saudi Peninsula in general, and
the UAE in particular (see IPCC, 2007). Models
predict from 20% less to 10% more by 2050 and
a gap as wide as 45% less to 22% more by 2100
(UAE, 2006b). Given the importance of rainfall
intensity and timing as an ecological driver, it is
unlikely that we can make a definitive assessment
of potential environmental consequences due
to <strong>climate</strong> <strong>change</strong> alone in the UAE.
However, we can explore dryland ecosystem
vulnerabilities in the UAE that pertain to <strong>climate</strong>
<strong>change</strong>, and heed lessons from other similar
biomes which have been more extensively
studied. In each of the four case studies which
follow, we explore the potential for a thresholdtype
of ecosystem <strong>change</strong>, and its implications
for biodiversity in the United Arab Emirates.
Avian migration and phenological
<strong>change</strong>
Nearly 81% of listed higher vertebrate species in
the Abu Dhabi Emirate are birds. Amongst the
avian species are insectivores (such as larks),
scavengers (buzzards and ravens), predators
Impacts, Vulnerability & Adaptation for
Dryland Ecosystems in Abu Dhabi
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