Accomplishments, failures and challenges in tropical ...€¦ · Accomplishments, failures and...
Transcript of Accomplishments, failures and challenges in tropical ...€¦ · Accomplishments, failures and...
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Accomplishments, failures and challenges in tropical forest
ecology: a personal perspective on 40 years'
research
David B. ClarkUniversity of Missouri- St. Louis
St. Louis, MO USA
Forest ecology: Processes and structure related to
capturing energy and producing and retaining
biomass, e.g. productivity, disturbance, turnover,
nutrient cycling, physical and biological structure of
tropical forests.
Accomplishments in tropical forest
ecology over the last 40 years
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Parque Nacional
Braulio Carrillo
La SelvaParcelas de vegetación
Parcelas de Muestreo(AMI) = 100ha
TransectoAltitudinalLa Selva – PNBC,100 – 2800 msnm
Area de Monitoreo Integrado
Volcán Barva
Steady progress in increasing the size and number for forest inventory plots, cf. CTFS, RainFor, CI TEAM Project, ABERG.
Reviewer #2 “This paper is utterly lacking in scholarship”
Modified from Wright et al. Cons. Biol. 2009
Global climate change is
universal – all forests in the
world have been impacted
from rising temperature
and CO2 levels.
Drake, J.B.,et al. 2002. Estimation of tropical forest
structural characteristics using large-footprint lidar. Remote
Sensing of Environment 79:305-319.
Development,
maturation, and wide-
spread application of
powerful remote sensing
technologies including
radar, lidar and high-
spatial resolution optical
sensors. Multiple
collaborations between
forest ecologists and
remote sensing scientists.
Spatial scale from
individual trees to the
entire world.
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J.M. Read et al. 2003. Application of 1-m and 4-m resolution satellite data to research and management in tropical forests.
Journal of Applied Ecology 40: 592-600.
High-spatial-resolution satellite data make possible canopy tree demography from space.
Clark, D.B. et al. 2004. Quantifying
mortality of tropical rain forest trees using
high-spatial-resolution satellite data.
Ecology Letters 7:52-59.
Single-pass lidar can produce landscape-scale estimates of forest structure
including basal area, biomass, canopy gap frequency and Leaf Area Index.
Drake, J.B. et al. 2002. Estimation of tropical forest structural characteristics using large-footprint lidar.
Remote Sensing of Environment 79:305-319.
Repeat lidar overflights can establish carbon source/sink status of
entire landscapes
Dubayah, R.O. et al. 2010. Estimation of
tropical forest height and biomass dynamics
using lidar remote sensing at La Selva, Costa
Rica. Journal of Geophysical Research –
Biogeosciences doi:10.1029/2009JG000933.
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Radar remote sensing, which penetrates clouds, can be
combined with optical, lidar, and ground data, to
estimate biomass at global scales
Saatchi et al. PNAS 2011Site history and sampling design have emerged as important
factors for interpreting results from forest inventory plots
Körner 2003 Science 300:1242-1243
Fisher et al. (2008) Ecology Letters 11:554-563.
GPS: a massive step forward for spatially-referenced field studies in tropical ecology
Where are my
#@!&+^$ satellites? Yep,
we’re
lost
Thomas, R.Q. et al. 2013. Low mortality in
tall tropical trees. Ecology 94:920-929
The combination of GPS
capability and GIS
analysis tools make
possible landscape-
scale studies even in
roadless areas of
continuous forest.
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Dramatic increase in the number of forest ecologists in tropical
countries, many trained in OTS and OTS-like courses around the world
Internet connectivity has revolutionized the flow of information
between rural and urban areas and among countries.
936,000 hits on “tropical secondary forest”
Exponential increase in research in tropical secondary and managed forests
Hurtado, J. and D.B. Clark. 2011. Local technicians in long-term research projects: evaluation of 25 years
experience in an active tropical research station. Revista de Biología Tropical 59:1455-1462.
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Areas where progress has been slow, negligible, or negative
Clark, D.A., D.B. Clark and S.F. Oberbauer.
2013. Field-quantified responses of tropical
rainforest aboveground productivity to
increasing CO2 and climatic stress, 1997-
2009. Journal of Biogeosciences 118:1–12.
Few studies use measured forest response to measured climate variables to
test current hypotheses linking forest productivity to changing climate.
There is an pronounced overabundance of modeling and hypothesis
generation in relation to field tests of models and hypotheses with long-term
forest performance data.
Clark, D.A et al. 2013. Journal of Biogeosciences 118:1–12.
Failure to adequately
sample tropical forest
landscapes in space………
…and time
Tropical forest ecologists and remote sensing scientists have
repeatedly committed the “fallacy of misplaced
concreteness”, confounding the abstract (estimates) with the
concrete things.
Well-defined and useful concepts such as biomass, Leaf Area
Index and Net Primary Productivity are being replaced with
terms with the same name but different meanings.
Estimates are not the same thing as direct measurements,
and failure to distinguish the two impedes theoretical and
practical progress.
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As a profession we have failed to create a culture of free
access to the data and metadata behind published papers.
As a result, our science depends virtually entirely on results
which cannot be independently replicated or verified.
Tropical forest ecology moving forward
How to we maintain existing magnet research sites and establish
new ones to increase the diversity of sampling of tropical old-
growth, secondary and managed forests?
One example: the CARBONO Project
1997-present
Focus is on sub-annual to annual sampling
of major components of above-ground NPP
and the impacts of climate on ANPP*
Longest data set in the tropics on annually-
measured ANPP* (wood growth + complete
litterfall by components)
18 0.5 ha plots in random design stratified
by soil nutrient status and topography
100+ publications and many dozen scientists
and students
Annual operating budget $90,000 including
two full-time local technicians
Clark et al. 2010. Global Change Biology 16:747-759.
Forest performance-climate interactions are most evident at time scales from
minutes to one year, but most TRF forest ecology studies use multi-annual census
intervals or very short time scales. We need more studies on time-scales that can be
used to quantify and predict the effects of climate change on forest productivity and
dynamics.
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Tang, H.et al. 2012. Remote Sensing of Environment 124:242–250.
Forest ecologists and
remote sensing
scientists must work to
carry out ground
measurements at the
same spatial scale as
remotely-sensed
observations.
This is not easy, but it
is possible for high-
spatial resolution
sensors.
Free and open data
access
Complete metadata
No sign-in requirement
No usage restrictions
We need to develop a new professional culture of open access to data
and metadata
Thank you for:
Financial support: U.S. National Science Foundation,
U.S. NASA, U.S. Department of Energy, TEAM Project-
Conservation International, Andrew W. Mellon
Foundation, Organization for Tropical Studies.
Logistic and administrative support: staff of the La
Selva Biological Station and the Costa Rican and North
American offices of the Organization for Tropical
Studies.
Permission to carry out field research for 30+ years
in Costa Rica: Ministerio del Ambiente y Energía.
And most especially my deep gratitude to the Costa
Rican field technicians over the decades, particularly Leonel Campos, William Miranda,
Marcos Molina and Gilbert Hurtado.
D.B. Clark publications: www.umsl.edu/~biology/faculty/davidclark.html