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NOVEL TROPICAL FORESTS THE NATURAL OUTCOME OF ENVIRONMENTAL CHANGE

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NOVEL TROPICAL FORESTS THE NATURAL OUTCOME OF ENVIRONMENTAL CHANGE Powered By Docstoc
					USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

 NOVEL TROPICAL FORESTS:
  THE NATURAL OUTCOME
   OF ENVIRONMENTAL
         CHANGE
                Ariel E. Lugo
International Institute of Tropical Forestry
            US Forest Service
               Río Piedras, PR
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
                           My Main Points Today
 • Extrapolating climate change effects from one
   scale of organization to another requires caution.
 • Climate change and land cover change require
   simultaneous consideration due to their synergy
   and the scale of influence of both types of change.
 • Anthropogenic disturbances change species
   composition and involve the spread of introduced
   species.
 • This sets the biota in movement both ecologically
   and evolutionarily.
 • On the long-term, changes in species composition
   will be more significant ecologically than changes in
   rate processes.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service


            Anthropogenic
            Disturbances


                               Global Climate
                                                                       Biota and Landscape in
                               Change Wildcard
                                                                              Turmoil


             Natural Disturbances




         The System we Must Understand to Manage our Future




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service


                         The Issues
             Directional vs. Cyclic
             Environmental Change
                     And
             Long-Term Response
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
Disturbances: inducers of biotic creativity
                                                          Jentsch et al. 2007




  derail, undo, and reorient whatever might have been accumulating
  during “normal” times.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

    Disturbances and Invasions
  • Natural disturbances maintain native
    species.
  • Anthropogenic disturbances add new
    conditions to the disturbance regime
    that favor the invasion of introduced
    species.
  • Combinations of disturbances act
    synergistically and make invasions more
    certain.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
    Examples of Long-Term Effects of Land Use
          Change on Species Composition
  • In Puerto Rico, since 1936 (Thompson et
    al. 2002).
  • In France, over millennia (Dambrine et
    al. 2007).
  • North America and Europe, over
    centuries (Vellend et al. 2007).
  • Australia (Cramer and Hobbs 2007).
  • New England (Foster and Aber 2004).
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service




     Changing
     Conditions


                                                                               Steady Function
                             Changing Species Composition




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service




   Given all the environmental
   changes and anthropogenic
   modification of landscapes,
   what is the reaction of the
              biota?

     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                                                ... 65 years of Research and Service

                  Increased Importance of Aliens
                                                                                                                  Erythrina poepigiana
                              50
                                                                                                                  Mangifera indica
                              45                                                                                  Citrus sinensis
 Importance Value (percent)




                              40                                                                                  Spathodea campanulata

                              35                                                                                  Syzygium jambos
                                                                                                                  Inga fagifolia
                              30
                                                                                                                  Casearia silvestris
                              25
                                                                                                                  Casearia guianensis
                              20                                                                                  Tabebuia heterophylla
                              15                                                                                  Cecropia shreberiana
                              10                                                                                  Andira inermis

                               5                                                                                  Inga vera
                                                                                                                  Guarea guidonia
                               0
                                          1980                     1990                      2002

                               USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
               90


               80


               70


               60


               50

                                                                 All Forests dbh>11.5 cm
               40
                                                                 Shade Coffee

                                                                 Karst Forests
               30
                                                                 Dry Forests

                                                                 Moist Forests
               20
                                                                 Wet Forests

                                                                 Mature Wet Forest dbh> 4 cm
               10
                                                                 Mature Dry Forest dbh> 5 cm

                0
                    0.0      0.2         0.4         0.6         0.8             1.0           1.2
                                                 Area (ha)


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY

   An Alien Approaches an Endangered
                                                      ... 65 years of Research and Service


                 Plant




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                       ... 65 years of Research and Service
                     Effects of Urbanization
  •   Species extinctions
  •   Fragmentation of landscapes
  •   Habitat conversion
  •   Extirpation of species
  •   Homogenization of species*
  •   New habitats
  •   Favor introduced species
  •   Ecological novelty
  •   Genetic and species diversity
  •   Diversify the landscape
      USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

        Jaccard Similarity Index
  • Compares species one to one;
    presence/absence; weights them equally.
  • Does not correct for relative
    quantitative presence (importance) of
    the species.
  • Ignores the mixing of species
  • Two floras can be identical but assemble
    into different communities with great
    ecological consequences.

     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                       ... 65 years of Research and Service
                  Invasions
 •   Promote evolutionary diversification
 •   Allopatric populations in new
     environments
 •   Altered ecological opportunities for
     native species
 •   New opportunities for hybridization
     between previously allopatric taxa

      USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                       ... 65 years of Research and Service
           Evolutionary Considerations
  •   Cryptic species invasions
  •   Phenotypic plasticity
  •   General purpose phenotypes
  •   Non-additive genetic variation
  •   Hybridization
  •   Introgression (genetic swamping)*
  •   Polyploidy
  •   Trait genetic variation
      USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY

                                  Predictions
                                                      ... 65 years of Research and Service



  • Novel forest types will emerge within complex
    and diverse landscapes.
  • They will self-assemble and self-organize.
  • Contain novel combinations and proportions of
    species.
  • Will exhibit a suite of species diversity levels
    similar to that in current forests.
  • Will function normally, no loss of services.


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
       Elements of a Holistic Approach
 • Focus on the long-term behavior of complex tropical
   forests and the synergy within and between
   ecosystems and external disturbance forces.
 • Be transparent in the analysis by stating
   assumptions.
 • Focus on both the resilience, including the
   adaptability, and vulnerabilities of the biota.
 • Distinguish between short and long-term system
   responses.
 • Recognize the emerging system properties with
   changing levels of biotic organization
 • Focus on all species and all environments.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service



 Comments?
 Questions?




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

                                       Tactics
  • Account for new species combinations in fragmented
    landscapes.
  • Give attention to the ecological flexibility of species.
  • Recognize that species will perform roles that may
    appear unnatural in a continuum of communities, but
    not in fragments.
  • Address new scientific challenges posed by novel
    communities.




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service


                                 New Forests
  • Have the same structural characteristics as
    native forests.
  • Are young and lack old growth characteristics.
  • Are carbon sinks.
  • Function like native forests, but at different
    rates.
  • Improve site conditions and foster native
    species.
  • Occur on fragmented landscapes; many times in
    places where native species cannot grow.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
                         Species Migrations
• Assuming that today’s species distributions enable
  predictions of tomorrow’s species distributions might not
  always be true.
• Species with small native ranges but large naturalized
  distributions and species with large native ranges, but
  growing in naturalized ranges outside their predicted
  climate envelope, do not fit the models as they cause a
  climate envelop mismatch.
• Experience with introduced species change the rules of
  the game.
• Species movements are accelerated by anthropogenic
  vectors acting on introduced species and the
  acceleration of novel climate formation by human
  activity.
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
Short-Term Data are Misleading and an Obstacle
  to Understanding of Long-Term Phenomena
           • Trees > 10 cm dbh recruit and die twice as fast on rich than on
             poor soils.
           • Tree turnover rates have increased throughout the Amazon
             over the last two decades.
           • Tree mortality and recruitment have increased in all regions
             except for mortality in eastern Amazonia.
           • Tree recruitment rates have consistently exceeded tree
             mortality rates.
           • Absolute increases in tree recruitment and mortality rates are
             greater in western Amazonia.
           • Tree mortality appears to be lagging tree recruitment at
             regional scales.
           • Tree biomass is increasing in these forests.



     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                       ... 65 years of Research and Service
        Why Are The Data Misleading
  •   Not based on an established
      pattern against to which compare.
  •   Data set is too short (25 yr overall
      but 10.1 yr per plot).
  •   Only a few plots exhibit the
      pattern advocate for the whole
      group. Most plots show no trend.
  •   Results appear normal
      USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                           ... 65 years of Research and Service
  1800


  1700


  1600


  1500


  1400


  1300


  1200
     1940             1950           1960           1970           1980           1990           2000   2010
                                                            Year



         USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                        ... 65 years of Research and Service

   300
   280
   260
   240
   220
   200
   180
   160
   140
   120
   100
     1940          1950           1960           1970           1980          1990           2000   2010
                                                         Year


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
                  Normal Rates of Mortality
       3.5
                            Range
       3.0

       2.5

       2.0

       1.5
                 Mean for
                 tropical forests
       1.0

       0.5

       0.0
             0     1    2     3      4     5     6     7      8     9    10     11    12    13     14
                                                      Plot

     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

         What These Data Show
  • Healthy and productive group of
    tropical forests.
  • Behaving normally, growing, accumulating
    biomass, and exhibiting regional
    differences.
  • The rates or mortality and biomass
    accumulation are low to average.


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY

            Conundrums, Paradoxes and
                                                      ... 65 years of Research and Service


               Ecological Surprises
  • Predictions of many extinctions due to climate
    change vs. low levels of extinctions during the
    last ice age (Botkin et al. 2007).
  • Invasive species causing a lot of harm and a
    lot of good.
  • Invasion Paradox.
  • Inbreeding Paradox.
  • Local Adaptation Paradox.
  • Frankenstein Effect.

     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

          One View of the Future
  • Rampant species invasions
  • Catastrophic levels of species
    extinctions
  • Homogenization of the biota
  • Disruptions of ecosystem services
  • Accelerated tree turnover



     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

    Definition of Novel Communities
     “Consist of species that are
           extant today, but in
       combinations not found at
                 present”
  (Williams & Jackson 2007, p 477)

  Defined earlier by Hobbs et al. (2006)
   and Lugo and Helmer (2004)
     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                                                                                                              ... 65 years of Research and Service

                                                                                                 100                                                                                          35

                                                                                                  90
                                                                                                                                                                                              30
                                                                                                  80




                                                                                                                                                                                                   Number of Tree Species
                                                                          Importance Value (%)
                                                                                                  70                                                                                          25

                                                                                                  60
                                                                                                                                                                                              20
                                                                                                  50
                                                                                                                                                                                              15
                                                                                                  40

                                                                                                  30                                                                                          10
                                                                                                  20
                                                                                                                                                                                              5
                                                                                                  10
                                                                                                       Alluvial Spathodea campanulata forests
                                                                                                   0                                                                                          0
                                                                                                         Big Trees                        Small Trees   Ground Vegetation




                           90                                                                               60                                                                   60                                                                           45

                           80                                                                                                                                                                                                                                 40
                                                                                                            50                                                                   50
                                                                                                                 Number of Tree Species




                                                                                                                                                                                                                                                                   Number of Tree Species
                           70                                                                                                                                                                                                                                 35
    Importance Value (%)




                                                                                                                                                          Importance Value (%)
                           60                                                                               40                                                                   40                                                                           30

                           50                                                                                                                                                                                                                                 25
                                                                                                            30                                                                   30
                           40                                                                                                                                                                                                                                 20

                           30                                                                               20                                                                   20                                                                           15

                           20                                                                                                                                                                                                                                 10
                                                                                                            10                                                                   10
                           10                                                                                                                                                                                                                                 5
                                Karst Spathodea campanulata forests                                                                                                                   Volcanic Spathodea campanulata forests
                            0                                                                               0                                                                     0                                                                           0
                                  Big Trees         Small Trees       Ground Vegetation                                                                                                  Big Trees                          Small Trees   Ground Vegetation




              USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

 Shoot First, Ask Questions Later
  • Based on inadequate research
    or poor understanding
  • Has unintended consequences
  • For Example, Pest Management
    in Agriculture


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY

       Why The Disagreements?
                                                      ... 65 years of Research and Service



  • Complex ecosystems and complex
    situations
  • Absence of empirical information and
    understanding
  • Different approaches
  • Generalizations across scales and
    disciplines
  • Subjectivity

     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service

   It provides an ecological service




     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926
USFS INTERNATIONAL INSTITUTE OF TROPICAL FORESTRY
                                                      ... 65 years of Research and Service
  “Previous work has failed to adequately take
    into account mechanisms of persistence”
   Such as:
   • Resilience of species
   • Succession after abandonment
   • Refuges or landscape fragments
   • Dispersal of species


     USDA Forest Service • IITF • Jardín Botánico Sur • 1201 Calle Ceiba • Rio Piedras, PR 00926

				
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