Lack of mutualisms as barrier for Pinaceae invasion* Biological invasions are a problem

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1 Lack of mutualisms as barrier for Pinaceae invasion* Martin A. Nuñez 1, Thomas R. Horton 2, & Daniel Simberloff 1 1 Dept. of Ecology and Evolutionary Biology, The University of Tennessee 2 Department of Environmental and Forest Biology, SUNY-ESF *Please contact Martin Nuñez (mnunez@utk.edu) if you plan to use the entire presentation or parts of it. Some pictures are copyrighted and most results are unpublished. Biological invasions are a problem

2 Pines are native to the Northern hemisphere and highly invasive in the Southern hemisphere Map from: Pine invasions in the southern hemisphere Monterey pine Australia Maritime Pine South Africa Slash Pine Brazil Lodgepole pine N. Zealand Monterey pine Chile Khasi Pine Madagascar Photos from David Richardson

3 We know little about the factors controlling invasive species Historically the study of invasions have been focused on negative interactions Enemy Release Hypothesis Biotic Resistance Hypothesis (Elton 1958)

4 Mycorrhizae Plant-fungi mutualism

5 Many attempts to plant pines failed due to the absence of mycorrhizae 5 year old pine WITHOUT mycorrhizae 6 year old pine with mycorrhizae There is evidence of lack of inoculation outside plantations in Australia, NZ and USA (areas where pines are not native)

6 Isla Victoria, Nahuel Huapi Nat. Park *. History of exotic tree introduction on Isla Victoria exotic spp were planted (62 conifers) Nahuel Huapi Lake Plantations were not removed

7 Observed pattern of invasion: -High densities of exotic trees only near plantations (<50 m) Hypothesis The presence of compatible ectomycorrhizal (EM) fungi on the island controls the invasion by different species of exotic Pinaceae through mycorrhizal facilitation.

8 Greenhouse experiment Field experiment Molecular and observational studies Greenhouse Inoculum increased the biomass 3x Aboveground m ass Biomass (g) (g) close with ECM addition Cerca Con adición de inóculo close w/out ECM Cerca addition Sin adición de inóculo Far with ECM additon Ponderosa pine Lejos Con adición de inóculo Far W/out ECM addition Lejos Sin adición de inóculo sterile Suelo estéril

9 Lodgepole pine Aboveground biomass (g) Douglas fir Ponderosa pine Field experiment In areas near and far from plantations Seeds of 3 species of exotic Pinaceae. Treatment Controls Controls With Inoculum addition With Inoculum (Soil from plantations) Local Soil Without Inoculum addition Sterlilized Inoculum

10 C lo se to p la n ta tio n s F a rfro m p la ta tio n s Field experiment Seedlings grew more near plantation Aboveground biomass (g) mass (g) Ponderosa pine Near Close to plantations Far Far from plantations Proportion of plots with seedlings Inoculation Increases Establishment Ponderosa pine Near Far Area and treatment (inoculum addition) showed significant differences.

11 Morphological & Molecular Analyses We analyzed fungal colonization using morphological and molecular (RFLPs and sequencing) techniques Morphological & Molecular Analyses 71% of the seedlings with soil near plantation were colonized by EM fungi Only 16% of the seedlings growing with soil from far from plantations were colonized * Without artificial inoculation

12 Molecular analyses 20 species of Mycorrhizal fungi found in soils from areas near plantations 3 species found far from plantations Molecular analyses Aprox. 50% of the samples from soil from areas near plantations were colonized by two species: Wilcoxina mikolae and Rhizopogon sp.

13 Wilcoxina mikolae Most abundant species Present in 27% of the seedlings near plantations Never found far from plantations Wilcoxina mikolae Rhizopogon sp.: 2 nd most abundant species Present in 21% of the seedlings near plantations Never found far from plantations

14 Conclusions The lack of proper EM species can be retarding the invasion Mycelium networks and spore banks can be important regulating the invasion It is important to understand more about EM dispersal and invasion. Lack of proper mycorrhizal fungi can help explain the observed time lag for Pinaceae invasion. It is possible that other invasions are controlled by this mechanism since it is largely ignored under the assumption that small things are everywhere. Thanks!

15 Acknowledgments R Dimarco J Karlanian F Ginnani N Barrios E. Perner M Nuñez M R-Cabal E Bargas A. Relva N. Sanders A. Classen K. Hughes J. Weltzin A. Barun L. Souza A. Read G. Crutsinger D. Richardson Jed Cappellazzi Lindsey Miller Ariel Cowan Park ranger Tata Mujica National Park Administration