Altered climate leads to positive density‐dependent feedbacks in a tropical wet forest

Climate change is predicted to result in warmer and drier Neotropical forests relative to current conditions. Negative density‐dependent feedbacks, mediated by natural enemies, are key to maintaining the high diversity of tree species found in the tropics, yet we have little understanding of how projected changes in climate are likely to affect these critical controls. Over 3 years, we evaluated the effects of a natural drought and in situ experimental warming on density‐dependent feedbacks on seedling demography in a wet tropical forest in Puerto Rico. In the +4°C warming treatment, we found that seedling survival increased with increasing density of the same species (conspecific). These positive density‐dependent feedbacks were not associated with a decrease in aboveground natural enemy pressure. If positive density‐dependent feedbacks are not transient, the diversity of tropical wet forests, which may rely on negative density dependence to drive diversity, could decline in a future warmer, drier world.

[1]  A. Valiente‐Banuet,et al.  Mycorrhizal symbiosis increases the benefits of plant facilitative interactions , 2018, Ecography.

[2]  W. Silver,et al.  Drought drives rapid shifts in tropical rainforest soil biogeochemistry and greenhouse gas emissions , 2018, Nature Communications.

[3]  S. Power,et al.  Experimentally altered rainfall regimes and host root traits affect grassland arbuscular mycorrhizal fungal communities , 2018, Molecular ecology.

[4]  Michelle E. Afkhami,et al.  Microbial mitigation-exacerbation continuum: a novel framework for microbiome effects on hosts in the face of stress. , 2018, Ecology.

[5]  J. Zimmerman,et al.  Environmental heterogeneity and biotic interactions mediate climate impacts on tropical forest regeneration , 2018, Global change biology.

[6]  G. González,et al.  Infrared heater system for warming tropical forest understory plants and soils , 2018, Ecology and evolution.

[7]  J. Zimmerman,et al.  Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species. , 2017, Ecology.

[8]  D. Rodriguez,et al.  Projections of climate change impacts on central America tropical rainforest , 2017, Climatic Change.

[9]  K. Ogle,et al.  Legacy effects of drought in the southwestern United States: A multi‐species synthesis , 2016 .

[10]  James S Clark,et al.  Multiyear drought-induced morbidity preceding tree death in southeastern U.S. forests. , 2015, Ecological applications : a publication of the Ecological Society of America.

[11]  C. Vriesendorp,et al.  Negative density-dependent mortality varies over time in a wet tropical forest, advantaging rare species, common species, or no species , 2015, Oecologia.

[12]  Wei Yang,et al.  Arbuscular mycorrhizal fungal community response to warming and nitrogen addition in a semiarid steppe ecosystem , 2015, Mycorrhiza.

[13]  Shixiao Yu,et al.  Arbuscular mycorrhizal fungi counteract the Janzen-Connell effect of soil pathogens. , 2015, Ecology.

[14]  Noelle G. Beckman,et al.  Testing predictions of the Janzen–Connell hypothesis: a meta-analysis of experimental evidence for distance- and density-dependent seed and seedling survival , 2014, The Journal of ecology.

[15]  F. Pugnaire,et al.  A role for below‐ground biota in plant–plant facilitation , 2013 .

[16]  B. Bachelot,et al.  Rare species advantage? Richness of damage types due to natural enemies increases with species abundance in a wet tropical forest , 2013 .

[17]  A. Valiente‐Banuet,et al.  Plant facilitation occurs between species differing in their associated arbuscular mycorrhizal fungi. , 2012, The New phytologist.

[18]  R. Freckleton,et al.  Consequences of changing rainfall for fungal pathogen-induced mortality in tropical tree seedlings , 2012, Ecology and evolution.

[19]  M. Torn,et al.  Warming accelerates decomposition of decades-old carbon in forest soils , 2012, Proceedings of the National Academy of Sciences.

[20]  Wen‐Hao Zhang,et al.  Day and night warming have different effect on root lifespan , 2012 .

[21]  Silvia Dorn,et al.  Drought changes plant chemistry and causes contrasting responses in lepidopteran herbivores , 2011 .

[22]  Ambarish V. Karmalkar,et al.  Climate change in Central America and Mexico: regional climate model validation and climate change projections , 2011 .

[23]  Christine V. Hawkes,et al.  Fungal community responses to precipitation , 2011 .

[24]  Eliot J. B. McIntire,et al.  Under strong niche overlap conspecifics do not compete but help each other to survive: facilitation at the intraspecific level , 2010 .

[25]  R. Freckleton,et al.  Testing the Janzen-Connell mechanism: pathogens cause overcompensating density dependence in a tropical tree. , 2010, Ecology letters.

[26]  Angela Sessitsch,et al.  Climate change e¡ects on bene¢cial plant^microorganism interactions , 2010 .

[27]  M. Visser,et al.  Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[28]  S Joseph Wright,et al.  The future of tropical forests , 2010, Annals of the New York Academy of Sciences.

[29]  Lorena Gómez Aparicio.  The role of plant interactions in the restoration of degraded ecosystems: a meta-analysis across life-forms and ecosystems , 2009 .

[30]  W. H. Putten.  A multitrophic perspective on functioning and evolution of facilitation in plant communities , 2009 .

[31]  L. Gómez‐Aparicio,et al.  The role of plant interactions in the restoration of degraded ecosystems: a meta‐analysis across life‐forms and ecosystems , 2009 .

[32]  M. V. D. van der Heijden,et al.  Socialism in soil? The importance of mycorrhizal fungal networks for facilitation in natural ecosystems , 2009 .

[33]  Christopher J. Lortie,et al.  Refining the stress‐gradient hypothesis for competition and facilitation in plant communities , 2009 .

[34]  F. Maestre,et al.  Balance between facilitation and resource competition determines biomass-density relationships in plant populations. , 2008, Ecology letters.

[35]  M. Bertness,et al.  Switching from negative to positive density-dependence among populations of a cobble beach plant , 2008, Oecologia.

[36]  A. Fitter,et al.  Soil temperature affects carbon allocation within arbuscular mycorrhizal networks and carbon transport from plant to fungus , 2008 .

[37]  M. Miriti.  Ontogenetic shift from facilitation to competition in a desert shrub , 2006 .

[38]  Andrea Vannini,et al.  Interactive effects of drought and pathogens in forest trees , 2006 .

[39]  S. Milton,et al.  Context-dependent interactions between adult shrubs and seedlings in a semi-arid shrubland , 2005 .

[40]  J. Harte,et al.  Response of plant pathogens and herbivores to a warming experiment , 2004 .

[41]  R. Norby,et al.  CO2 enrichment and warming of the atmosphere enhance both productivity and mortality of maple tree fine roots , 2004 .

[42]  Andrea F. Huberty,et al.  PLANT WATER STRESS AND ITS CONSEQUENCES FOR HERBIVOROUS INSECTS: A NEW SYNTHESIS , 2004 .

[43]  J. Öhrvik,et al.  Interactive effects of soil warming and fertilization on root production, mortality, and longevity in a Norway spruce stand in Northern Sweden , 2004 .

[44]  M. Hochberg,et al.  Defence against multiple enemies , 2003, Journal of evolutionary biology.

[45]  N. Enright,et al.  The Role of Cloud Combing and Shading by Isolated Trees in the Succession from Maquis to Rain Forest in New Caledonia1 , 2002 .

[46]  C. Field,et al.  Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland , 2002 .

[47]  V. Brown,et al.  SUCCESSION IN OLD PASTURES OF CENTRAL AMAZONIA: ROLE OF SOIL FERTILITY AND PLANT LITTER , 2002 .

[48]  T. M. Bezemer,et al.  Herbivory in global climate change research: direct effects of rising temperature on insect herbivores , 2002 .

[49]  R. Augé.  Water relations, drought and vesicular-arbuscular mycorrhizal symbiosis , 2001, Mycorrhiza.

[50]  C. Labandeira,et al.  Response of plant-insect associations to paleocene-eocene warming , 1999, Science.

[51]  Andrew Gelman,et al.  General methods for monitoring convergence of iterative simulations , 1998 .

[52]  Ian R. Sanders,et al.  Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity , 1998, Nature.

[53]  A. Fitter,et al.  Does elevated atmospheric carbon dioxide affect arbuscular mycorrhizas? , 1998, Trends in ecology & evolution.

[54]  P. Coley,et al.  Possible Effects of Climate Change on Plant/Herbivore Interactions in Moist Tropical Forests , 1998 .

[55]  D. Nepstad,et al.  The role of the shrub Cordia multispicata Cham. as a ‘succession facilitator’ in an abandoned pasture, Paragominas, Amazônia , 1994, Vegetatio.

[56]  M. Bertness,et al.  Positive interactions in communities. , 1994, Trends in ecology & evolution.

[57]  Michael Taylor.  Diversity of life , 1994, Nature.

[58]  G. Fairchild,et al.  A new method which gives an objective measure of colonization of roots by vesicular-arbuscular mycorrhizal fungi. , 1990, The New phytologist.

[59]  C. Augspurger.  Seedling Survival of Tropical Tree Species: Interactions of Dispersal Distance, Light-Gaps, and Pathogens , 1984 .

[60]  D. Clark,et al.  Spacing Dynamics of a Tropical Rain Forest Tree: Evaluation of the Janzen-Connell Model , 1984, The American Naturalist.

[61]  H. Wolda.  SEASONAL FLUCTUATIONS IN RAINFALL, FOOD AND ABUNDANCE OF TROPICAL INSECTS , 1978 .

[62]  D. Janzen.  Herbivores and the Number of Tree Species in Tropical Forests , 1970, The American Naturalist.

[63]  J. M. Phillips,et al.  Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection. , 1970 .

[64]  T. White.  An index to measure weather-induced stress of trees associated with outbreaks of Psyllids in Australia , 1969 .

[65]  Nunzio Knerr,et al.  A comparison of network and clustering methods to detect biogeographical regions , 2018 .

[66]  C. Lortie,et al.  Functional assessment of animal interactions with shrub‐facilitation complexes: a formal synthesis and conceptual framework , 2016 .

[67]  R. Bardgett,et al.  Influence of soil microbiota in nurse plant systems , 2016 .

[68]  F. Pugnaire,et al.  Does the stress‐gradient hypothesis hold water? Disentangling spatial and temporal variation in plant effects on soil moisture in dryland systems , 2016 .

[69]  F. Pugnaire,et al.  Facilitation in communities: underlying mechanisms, community and ecosystem implications , 2016 .

[70]  David B. Dunson,et al.  Bayesian data analysis, third edition , 2013 .

[71]  J. McNicol,et al.  Elevated CO2 and aboveground–belowground herbivory by the clover root weevil , 2009, Oecologia.

[72]  S. Chown,et al.  Physiological Diversity in Insects: Ecological and Evolutionary Contexts. , 2006, Advances in insect physiology.

[73]  R. Kobe.  LIGHT GRADIENT PARTITIONING AMONG TROPICAL TREE SPECIES THROUGH DIFFERENTIAL SEEDLING MORTALITY AND GROWTH , 1999 .

[74]  Andres R. Garcia-Martino,et al.  Rainfall, Runoff and Elevation Relationships in the Luquillo Mountains of Puerto Rico* , 1996 .

[75]  F. Scatena.  An Introduction to the Physiography and History of the Bisley Experimental Watersheds in the Luquillo Mountains of Puerto Rico , 1989 .

[76]  J. Connell.  On the role of the natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees , 1971 .

[77]  L. Holdridge.  Life zone ecology. , 1967 .