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Slide 1 - New Jersey Institute of Technology

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					                                                                                                                                Déjà Vu Communities: When Invaders Meet Again
                                 Melanie Northrup, Christy Cincotta, Mark June-Wells, Jonathan Lansey, Kunj Patel, Apiwat Romayanantakit, Claus Holzapfel
                                                               Rutgers University Newark, Dept. of Biological Sciences, Newark NJ 07102-1811                                                                                                                                                                                                                      contact: holzapfe@andromeda.rutgers.edu


                     Abstract                                                                                                              Grid Transect Data                                                                                                                                                                            Root Interaction Experiment
Fallopia japonica and Microstegium vimineum are two                Methods                                                                                                                                     Methods
sympatric northeast Asian plant species that are non-native
                                                                   Two parallel transects were taken perpendicular to the border between pairs of                                                              Interactions between three species pairs were tested in this experiment,
invaders in the Northeastern U.S. In some areas these two
                                                                   sympatric and allopatric species. Included in the study were 9 pairs of sympatric species                                                   including Fallopia vs. Microstegium, Fallopia vs. Artemisia, and Fallopia
species now co-occur and very clear boundaries between
                                                                   and 6 pairs of allopatric species across 5 sites in northern New Jersey. Each transect was                                                  vs. Solidago. Each arena ‘type’ was replicated 3 times, totaling 9 arenas.
populations of these two species appear to be typical, while
                                                                   3.5 x 0.5 m and composed of 50 x 50 cm quadrats. Measurements at the quadrat level                                                          Measurements included root mass at initiation, shoot height and number
overlap zones are typical when these species interact with
                                                                   included percentage vegetation cover, average height, and density of each species.                                                          of leaves weekly, root cores extracted at week 11, and root and shoot
other species. We are studying the interaction between
these two species testing the possibility that coevolved                                                                                                                                                       biomass upon harvest. Roots from root cores were washed, scanned and
community level interactions are involved when formerly            Results                                                                                                                                     then analyzed with WinRhizo Pro software to calculate root length.
sympatric species meet again in “déjà-vu communities”. We
used a grid transect method to assess aboveground                        Allopatric pairs have significantly larger overlap compared to sympatric                                                              Results
interactions between 9 pairs of sympatric species and 6                                                     pairs                                                                                                                                                                                                                                                             Average Fallopia japonica root length toward
pairs of allopatric species. Additionally, we conducted a                                                                                                                                                                           Average root length toward other plants
greenhouse experiment to assess belowground and                                                                 25                                                                                                                            or away from plants                                                                                                                    intra- or inter-specific neighbor

                                                                              Overlap (% of transect)
                                                                                                                                                   P=0.0130    Extent of overlap between bordering                                                                                                                                             Fallopia had significantly                                                                                                                          Fallopia grown with
aboveground interactions between native and non-native                                                          20                                                                                                                         300




                                                                                                                                                                                                                Average Root Length (cm)
co-occurring plants. Results from the grid transect surveys                                                                                                    monotypic stands of different origin.                                       250                                                                   Toward other plant
                                                                                                                                                                                                                                                                                                                                               (F = 7.29; p<.0001; n=6)                                             350                                                                            Artemisia had significantly
                                                                                                                15                                                                                                                                                                                                                                                                                                                                                    Toward Interspecific
showed that allopatric pairs have significantly larger                                                                                                         Overlap percentages are based on scaled                                     200                                                                   Toward wall                   more root length in the                                              300
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Toward Intraspecific
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   (F= 4.69; P<.0001; n=6)




                                                                                                                                                                                                                                                                                                                                                                                         Average Root Length (cm)
                                                                                                                10
overlap zones compared to sympatric species. The root                                                                                                          aboveground cover of each species along the                                 150                                                                                                 direction of other plants                                            250                                                                            greater average root length
interaction experiment implied that Fallopia produced less
                                                                                                                 5                                             transect. Shown are the means (+ SE) of                                     100                                                                                                 (intra- or inter-specific)                                           200                                                                            toward itself (intraspecific)
belowground growth and grew more toward itself                                                                   0                                             each pairing, the overall means of allopatric                                   50
                                                                                                                                                                                                                                                                                                                                               compared to away from                                                150
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   than toward Artemisia
                                                                                                                                                                                                                                                0
(intraspecific) when grown with Artemisia vulgaris as                                                                                                          and sympatric pairs (shown as horizontal                                                                                                                                        plants. Microstegium,                                                                                                                               (interspecific). Fallopia




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                                                                                                                                                               lines), and the p-value comparing overall                                                                                                                                       Solidago, and Artemisisa                                                                                                                            grown with Microstegium or




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opposed to Microstegium and Solidago canadensis. We




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                                                                                                                                                               means. There are 8 allopatric and 16                                                                                                                                            showed very little                                                                                                                                  Solidago showed no difference




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confirmed, with some reservation, that direct competition
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                                                                                                                                                               sympatric transects.                                                                                                                                                            differentiation in direction                                                                                                                        between intra- and inter-




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with the sympatric Microstegium is comparatively small.                                                                       Pairing




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                                                                                                                                                                                                                                                                                                                                                                                                                                Fallopia (FA)         Fallopia (FM)         Fallopia (FS)




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                                                                                                                                                                                                                                                                              Species/Arena                                                    of growth.                                                                                             Species/Arena                                specific neighbors.

                                                                                   Fallopia overlaps with sympatric species Microstegium less than with
                                                                                                        allopatric species Artemisia
                                                                                                                                                                                                               Fallopia japonica shoot height and number                                                                                                                      Belowground growth of Fallopia is correlated
                 Introduction                                                                                  Fallopia                            Microstegium                                                      of leaves by arena over 11 weeks                                                                                                                                 with biomass of other species
                                                                                                                                                                                                                                                                                                                                                   Although not                                                       8
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Belowground growth of
                                                                                                                                                                                                                                               180
Fallopia japonica and Microstegium vimineum are two non-
                                                                            Cover (scaled %)




                                                                                                        100
                                                                                                                                                                                                                                                                                                                                                   statistically                                                                                                                                         Fallopia is positively




                                                                                                                                                                                                                                                                                                                                                                               Belowground Biomass (Other
                                                                                                                                                                                                                                               160                      Fallopia (FA)                                                                                                                                 7
native invaders in the Northeastern United States. The                                                   80
                                                                                                                                                                                                                                               140                      Fallopia (FM)                                                              significant,                                                                                                                                          correlated (r=0.9924)
                                                                                                                                                                                                                                                                                                                                                                                                                      6                                                                 Solidago
former invaded the U.S. in the eighteen century (Forman                                                  60




                                                                                                                                                                                                                           Total Height (cm)
                                                                                                                                                                                                                                               120                      Fallopia (FS)
                                                                                                                                                                                                                                                                                                                                                   Fallopia showed                                                    5
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         with belowground
                                                                                                         40




                                                                                                                                                                                                                                                                                                                                                                                        Species)
and Kesseli 2003) and the later has become dominant much                                                                                                                                                                                       100                                                                                                 the greatest total                                                 4
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         biomass of other species
                                                                                                         20
more recently since its introduction in 1919 (Fairbrothers                                                                                                                                                                                      80
                                                                                                                                                                                                                                                                                                                                                   shoot height over                                                                                                                                     in their respective
                                                                                                          0                                                                                                                                                                                                                                                                                                           3
and Gray 1972). We have observed sharp borders between                                                               1    2        3           4    5     6    7
                                                                                                                                                                                                                                                60
                                                                                                                                                                                                                                                                                                                                                   time when grown                                                    2
                                                                                                                                                                                                                                                                                                                                                                                                                                                Microstegium                                             arenas. For example,
                                                                                                                                                                                                                                                40
these two sympatric species where they co-occur, but found                                                                                                                                                                                                                                                                                         with Artemisia                                                     1
                                                                                                                                                                                                                                                                                                                                                                                                                              Artemisia
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Fallopia grew the least
                                                                                                                                        Transect                                                                                                20
that these species have larger overlap zones when they                                                                                                                                                                                               0                                                                                             and the least with                                                 0                                                                                  when grown with
interact with other allopatric species (.i.e., species that                                                                                                                                                                                                   1         2    3          4          5         6      7       8        9   10   11   Microstegium.                                                          0                     20               40                60               80   Artemisia and Artemisia
originate from different geographic areas). These                                                                                                                                                                                                                                Measurement Number (Weekly)                                                                                                                                    Belowground growth (Fallopia )                           produced the least
                                                                                                               Fallopia                                 Artemisia
differences might relate to studies by Turkington and                                                                                                                                                                                                                                                                                                                                                                                                                                                    amount of belowground
Mehrhoff (1990) that list several cases in which plants                                                                                                                                                                                                                                                                                                                                                                                                                                                  biomass in that arena.
                                                                    Cover (scaled %)




                                                                                              100
perform better under interspecific competition with their
                                                                                               80
sympatric neighbors, as compared to their allopatric
neighbors. This evidence has been interpreted as providing
                                                                                               60
                                                                                               40                                                                                                              Discussion
a strong sign for co-evolution in communities (Lawlor and                                      20                                                                                                               Belowground growth of Fallopia is least when grown with Artemisia and most with Solidago, but aboveground growth (total shoot
Maynard-Smith 1976). Our field and greenhouse studies                                           0                                                                                                               height) of Fallopia is greatest when grown with Artemisia. It appears that when Fallopia and Artemisia are paired, Fallopia is
investigate belowground interactions and aboveground                                                             1        2       3        4        5     6     7                                               allocating more energy into aboveground growth as opposed to belowground growth. Our results also suggest that Fallopia grows well
patterns between pairs of sympatric and allopatric species.                                                                             Transect                                                                above- and below-ground when paired with Microstegium and Solidago. In general, this confirms our hypothesis that direct
                                                                                                                                                                                                                competition between Fallopia and Microstegium is comparatively small, therefore possibly suggesting recognition and cooperation
                                                                    Shown (above, left) is the area cover (average) along 3.5m long grid transects (grid size                                                   between these sympatric species. On the other hand, belowground growth of Fallopia and Artemisia, when grown together, was
                                                                    50x50 cm). These transects are centered at the boundary of monotypic stands.                                                                comparatively poor possibly suggesting strong direct competition, allelopathy or some other growth deterrents between allopatric
                                                                                                                                                                                                                species.

                                                                   Discussion                                                                                                                                  Future Directions
                                                                                                                                                                                                                • The root interaction experiment will be redesigned to assess one on one interactions between pairs of species and include a
                                                                   Pairs of sympatric species –species that originate from similar geographic areas –
                                                                                                                                                                                                                  greater number of replicates to obtain more conclusive results.
                                                                   tend to have smaller overlap zones between them compared to species pairs in
                                                                   which each originate from different areas. This difference, though significant, is
                                                                                                                                                                                                                • Initiation of a root chamber experiment to assess root interactions when plant roots are forced to grow into one another due to
                                                                   based on a fairly small data set. For instance it is not clear to us whether different
                                                                                                                                                                                                                  gravitational forces. Root interactions between plants can be observed over time as they grow along a Plexiglas viewing pane.
                                                                   subgroups of sympatric species (e.g. Asian, European or native North American
                                                                   species) show similar low levels of overlap avoidance. Moreover, the mechanisms
                                                                   underlying such “cooperation” are unclear and may be case specific.
                                                                                                                                                                                                                                                                                                                                                                References
                                                                                                                                                        Acknowledgements                                        Fairbrothers, D.E. and J.R. Gray. 1972. Microstegium vimineum (Trin.) A. Camus (Gramineae) in the United States. Bulletin of the Torrey Botanical Club 99(2): 97-100.
                                                                   We are grateful to a number of people who guided us to research sites and provided access:
                                                                   Betty Ann Kelly (Union County Dept. Parks & Recreation, New Jersey), Frank Gallagher                                                                           .
                                                                                                                                                                                                                Forman, J. and R.V Kesseli. 2003. Sexual reproduction in the invasive species Fallopia japonica (Polygonaceae). American Journal of Botany 90(4): 586-592.
                                                                   (Liberty State Park) and Martin Rapp (New Jersey Natural Lands Trust) and to Amitabha
                                                                   Bose (New Jersey Institute of Technology, UBM program) who was instrumental in                                                               Lawlor, L.R. and J. Maynard-Smith. 1976. The co-evolution and stability of competing species. American Naturalist 110: 79-99.
                                                                   keeping the undergraduates on the mathematical track.
                                                                                                                                                                                                                Turkington, R. and L.A. Mehrhoff. 1990. The role of competition in structuring pasture communities. In: Grace, J.B., Tilman, D. (Eds.) Perspectives on Plant
                                                                                                                                                                                                                     Competition, Academic, San Diego.

				
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