Research Paper

Recruitment dynamics mediated by ungulate herbivory can affect species coexistence for tree seedling assemblages

Chi-Yu Weng, Chih-hao Hsieh and Mong-Huai Su

Published on: 19 July 2017

Page: 283 - 293

DOI: 10.6165/tai.2017.62.283

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    Abstract

    The best-known mechanism that herbivory affects species coexistence of tree seedlings is negative density-dependency driven by specialist natural enemies. However, in a forest with intense herbivory by non-specialists, what causes a diversifying seedling bank if rare species do not benefit from negative density-dependency in dominant species? We hypothesize that generalist herbivores can cause unevenly distributed species-specific mortality, which mediates recruitment dynamics and therefore affects species coexistence. To answer this question, we conducted a fence-control experiment in a montane cloud forest, Taiwan, and found that herbivorous damages were mainly caused by ungulates, which are generalists. We explored ungulate herbivory effects on recruitment dynamics by censusing tree seedling dynamics for three years. We found that herbivorous damages by ungulates significantly cause seedling death, mostly at their early stage of establishment. The percentage of death caused by herbivory varied among species. In particular, nurse plants and seedling initial height help shade-tolerant species to persist under such intense herbivory. Whereas, deaths caused by other factors occurred more often in older seedlings, with a consistent low percentage among species. We then tested species coexistence maintenance by dynamic modelling under different scenarios of ungulate herbivory. Raising percentages of death by herbivory changes relative species abundances by suppressing light-demanding species and increasing shade-tolerant species. Density-dependent mortality immediately after bursts of recruitments can suppress dominance of abundant species. With ungulate herbivory, fluctuating recruitment further prevent rare species from apparent competition induced by abundant species. Such bio-processes can interact with ungulate herbivory so that long-term coexistence can be facilitated.

    Keyword: Dynamic modelling, Montane cloud forest, Recruitment dynamics, Seedling, Species coexistence, Ungulate herbivory

    Literature Cited

    Asquith, N.M., S.J. Wright and M.J. Clauss. 1997. Does mammal community composition control recruitment in neotropical forests?? Evidence from Panama. Ecology 78(3): 941-946.
    DOI: 10.2307/2266071View Article Google Scholar

    Bachelot, B., M. Ur?arte, J. Thompson and J.K. Zimmerman. 2016. The advantage of the extremes: tree seedlings at intermediate abundance in a tropical forest have the highest richness of above-ground enemies and suffer the most damage. J. Ecol. 104(1): 90-103.
    DOI: 10.1111/1365-2745.12488View Article Google Scholar

    Bagchi, R., R.E. Gallery, S. Gripenberg, S.J. Gurr, L. Narayan, C.E. Addis, R.P. Freckleton, and O.T. Lewis. 2014. Pathogens and insect herbivores drive rainforest plant diversity and composition. Nature 506(7486): 85-88.
    DOI: 10.1038/nature12911View Article Google Scholar

    Baraloto, C., and P.-M. Forget. 2007. Seed size, seedling morphology, and response to deep shade and damage in neotropical rain forest trees. Am. J. Bot. 94(6): 901-911.
    DOI: 10.3732/ajb.94.6.901View Article Google Scholar

    Comita, L.S., S.A. Queenborough, S.J. Murphy, J.L. Eck, K. Xu, M. Krishnadas, N. Beckman, and Y. Zhu. 2014. Testing predictions of the Janzen-Connell hypothesis: A meta-analysis of experimental evidence for distance- and density-dependent seed and seedling survival. J. Ecol. 102(4): 845-856.
    DOI: 10.1111/1365-2745.12232View Article Google Scholar

    Curran, L.M., and C.O. Webb. 2011. Experimental Tests of the Spatiotemporal Scale of Seed Predation in Mast-Fruiting Dipterocarpaceae. Ecol. Monogr. 70(1): 129-148.
    DOI: 10.1890/0012-9615(2000)070[0129:ETOTSS]2.0.CO;2View Article Google Scholar

    Dearing, M.D., A.M. Mangione, and W.H. Karasov. 2000. Diet breadth of mammalian herbivores: nutrient versus detoxification constraints. Oecologia 123(3): 397-405.
    DOI: 10.1007/s004420051027View Article Google Scholar

    Dyer, L.A., D.K. Letourneau, G.V. Chavarria, and D.S. Amoretti. 2010. Herbivores on a dominant understory shrub increase local plant diversity in rain forest communities. Ecology 91(12): 3707-3718.
    DOI: 10.1890/08-1634.1View Article Google Scholar

    George, L.O., and F.A. Bazzaz. 1999. The fern understory as an ecological filter: growth and survival of canopy-tree seedlings. Ecology 80(3): 846-856.
    DOI: 10.1890/0012-9658(1999)080[0846:TFUAAE]2.0.CO;2View Article Google Scholar

    Green, P.T., K.E. Harms, and J.H. Connell. 2014. Nonrandom, diversifying processes are disproportionately strong in the smallest size classes of a tropical forest. PNAS 111(52): 18649-18654.
    DOI: 10.1073/pnas.1321892112View Article Google Scholar

    Harms, K.E., S.J. Wright, O. Calder?n, A. Hern?ndez, and E.A. Herre. 2000. Pervasive density-dependent recruitment enhances seedling diversity in a tropical forest. Nature 404(6777): 493-495.
    DOI: 10.1038/35006630View Article Google Scholar

    Hidding, B., J.P. Tremblay, and S.D. C?t?. 2012. Survival and growth of balsam fir seedlings and saplings under multiple controlled ungulate densities. For. Ecol. Manage. 276: 96-103.
    DOI: 10.1016/j.foreco.2012.03.023View Article Google Scholar

    Hill, M.O. 1973. Diversity and evenness: a unifying notation and its consequences. Ecology 54(2): 427-432.
    DOI: 10.2307/1934352View Article Google Scholar

    Holt, R. D. 1977. Predation, Apparent Competition, and the Sctructure of Prey Communities. Theor. Popul. Biol. 12(2): 197-229.
    DOI: 10.1016/0040-5809(77)90042-9View Article Google Scholar

    Hubbell, S.P. 1979. Tree dispersion, abundance, and diversity in a tropical dry forest. Science 203(4387): 1299-1309.
    DOI: 10.1126/science.203.4387.1299View Article Google Scholar

    Hulme, P.E. 1996. Herbivory, plant regeneration, and species coexistence. J. Ecol. 84(4): 609-615.
    DOI: 10.2307/2261482View Article Google Scholar

    Hwang, M.H., and Y.Y. Chian. 2007. Monitoring larger mammals in the Nanzihshian logging road area, Yushan National Park, Taiwan. Taiwan J. For. Sci. 22: 135-148.

    Jansen, P. a, F. Bongers and L. Hemerik. 2004. Seed mass and mast seeding enhance dispersal by a neotropical scatter-hoarding rodent. Ecol. Monogr. 74(4): 569-589.
    DOI: 10.1890/03-4042View Article Google Scholar

    Jost, L. 2007. Partitioning diversity into independnet alpha andf beta components. Ecology 88(10): 2427-2439.
    DOI: 10.1890/06-1736.1View Article Google Scholar

    Kobe, R.K., and C.F. Vriesendorp. 2011. Conspecific density dependence in seedlings varies with species shade tolerance in a wet tropical forest. Ecol. Lett. 14(5): 503-510.
    DOI: 10.1111/j.1461-0248.2011.01612.xView Article Google Scholar

    Li, C.-F., M. Chytr?, D. Zelen?, M.-Y. Chen, T.-Y. Chen, C.-R. Chiou, Y.-J. Hsia, H.-Y. Liu, S.-Z. Yang, C.-L. Yeh, J.-C. Wang, C.-F. Yu, Y.-J. Lai, W.-C. Chao, and C.F. Hsieh. 2013. Classification of Taiwan forest vegetation. Appl. Veg. Sci. 16(4): 698-719.
    DOI: 10.1111/avsc.12025View Article Google Scholar

    Lischke, H., and T.J. L?ffler. 2006. Intra-specific density dependence is required to maintain species diversity in spatio-temporal forest simulations with reproduction. Ecol. Modell. 198(3-4): 341-361.
    DOI: 10.1016/j.ecolmodel.2006.05.005View Article Google Scholar

    Norghauer, J.M., and D.M. Newbery. 2014. Herbivores differentially limit the seedling growth and sapling recruitment of two dominant rain forest trees. Oecologia 174(2): 459-469.
    DOI: 10.1007/s00442-013-2769-6View Article Google Scholar

    Paine, C.E.T., H. Beck, and J. Terborgh. 2016. How mammalian predation contributes to tropical tree community structure. Ecology 97(12): 3326-3336.
    DOI: 10.1002/ecy.1586View Article Google Scholar

    Royo, A.A., and W.P. Carson. 2005. The herb community of a tropical forest in central Panam?: dynamics and impact of mammalian herbivores. Oecologia 145(1): 66-75.
    DOI: 10.1007/s00442-005-0079-3View Article Google Scholar

    Royo, A.A., and W.P. Carson. 2008. Direct and indirect effects of a dense understory on tree seedling recruitment in temperate forests: habitat-mediated predation versus competition. Can. J. For. Res. 38(6): 1634-1645.
    DOI: 10.1139/X07-247View Article Google Scholar

    Royo, A.A., R. Collins, M.B. Adams, C. Kirschbaum, and W.P. Carson. 2010. Pervasive interactions between ungulate browsers and disturbance regimes promote temperate forest herbaceous diversity. Ecology 91(1): 93-105.
    DOI: 10.1890/08-1680.1View Article Google Scholar

    Smit, C., and C. Vandenberghe. 2007. Nurse plants, tree saplings and grazing pressure: changes in facilitation along a biotic environmental gradient. Oecologia 152(2): 265-273.
    DOI: 10.1007/s00442-006-0650-6View Article Google Scholar

    Usinowicz, J., S.J. Wright, A.R. Ives, and D.F. Doak. 2012. Coexistence in tropical forests through asynchronous variation in annual seed production. Ecology 93(9): 2073-2084.
    DOI: 10.1890/11-1935.1View Article Google Scholar

    Weng, C.-Y., K.-C. Yang, C.-F. Hsieh, C.-H Hsieh, and M.-H. Su. 2017. Local neighborhood communities in the understory play a critical role by affecting regeneration niches and subsequent community assembly in a montane cloud forest. Ecological Research: (Online First)
    DOI: 10.1007/s11284-017-1475-yView Article Google Scholar

    Wright, S.J. 2002. Plant diversity in tropical forests: a review of mechanisms of species coexistence. Oecologia 130(1): 1-14.
    DOI: 10.1007/s004420100809View Article Google Scholar

    Wright, S.J., H.C. Muller-Landau, O. Calder?n, and A. Hernand?z. 2005. Annual and spatial variation in seedfall and seedling recruitment in a neotropical forest. Ecology 86(4): 848-860.
    DOI: 10.1890/03-0750View Article Google Scholar

    Yang, K.-C., J.-K. Lin, C.-F. Hsieh, C.-L. Huang, Y.-M. Chang, L.-H. Kuan, J.-F. Su, and S.-T. Chiu. 2008. Vegetation pattern and woody species composition of a broad-leaved forest at the upstream basin of Nantzuhsienhsi in mid-southern Taiwan. Taiwania 53(4): 325-337.
    DOI: 10.6165/tai.2008.53(4).325View Article Google Scholar