ECI Annual Review 2006/2007 - Environmental Change Institute ...

Ecosystem Dynamics
1
“We seek to
understand how
ecosystems
function; and
how they may
be affected by
direct human
pressures and
global atmospheric
change.”
Leader:
Dr Yadvinder Malhi
Jackson Fellow
The ECI Ecosystem Dynamics Programme
seeks to understand how
contemporary ecosystems function;
and how they may be affected by
direct human pressures and global
atmospheric change. The tools we
employ in our research include:
• Intensive field observation of
carbon, water and nutrient cycling;
vegetation and soil properties;
plant ecophysiology; and
climate.
• Multi-decadal and large-scale
monitoring and analysis of ecosystem
structure, composition
and dynamics.
• Quantitative modelling of ecosystem
ecophysiology and biogeochemical
cycling.
• Satellite remote sensing at local,
regional and global scales.
• Macro-ecological analysis of
plant function and traits.
Our interests are global, but we have
particularly active research in the
lowland tropical forests of Amazonia
and Africa, the montane forests
of the Andes, and the temperate
woodlands of the UK.
Projects
Examining the effect of recent
drought in Amazonia
The severe drought which affected
Amazonia in 2005 provides a unique
opportunity to assess the impact
and responses of biodiversity to extreme
conditions. The drought was
recorded as the most intense dry
period in the region since weather
records began in the mid-20th Century.
With its problems comes the
unique opportunity to evaluate the
impacts and the response of biodiversity
to extreme conditions, which
may be analogous to future climates
in a warming world.
Described as the ‘global centre of
tree diversity’, and containing between
a quarter and a third of the
world’s biodiversity, the Amazon is a
vital component of the biosphere. In
the last 25 years biomass and forest
growth rates in intact Amazonian
forests have been rising, possibly
resulting in a moderate carbon sink,
but this may be under threat from
climate change. This study aims to
use the recent drought to examine
how these tropical humid systems
respond to intense drought, assess
their recovery, and possible subsequent
decline.
North-west Amazonia in particular
usually has no dry season, and
vegetation there is expected to be
unlikely to adapt to even modest
seasonal drought. Therefore, impacts
are likely to exist at many levels,
as shown by earlier studies. They
are expected to include: increases
in rates of tree mortality; increased
litterfall; changes in rates of leaf production
and leaf loss; physiological
effects of drought stress; and inhibition
of photosynthesis.
The main objectives of the project
are to map the spatial and temporal
extent of the drought; to discover
the drought’s impact on tree-level
ecological indicators and on standlevel
ecological indicators (biomass,
growth, mortality, mode of mortality,
composition); and to quantify
drought responses and recovery of
ecosystem processes.
Climate change from the Amazon to
the Andes
We have embarked on a major research
programme in the Andes,
using a transect of study sites ranging
from the lowland Amazon forest
to the high Andes to understand
what determines the carbon dynamics
of Andean montane forests, and
how this may be altered by climate
change. Our field studies will focus
on a valley in the Peruvian Andes,
near Cuzco.
With funding from the Natural Environment
Research Council and
the Moore Foundation, seven members
of the Ecosystem Dynamics
Group are working on this project.
Although some initial fieldwork has
already started, our major fieldwork
investment will start in March 2007.