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Meakem V, Tepley AJ, Gonzalez-Akre EB, Herrmann V, Muller-Landau HC, Wright SJ, Hubbell SP, Condit R, Anderson-Teixeira KJ. Role of tree size in moist tropical forest carbon cycling and water deficit responses. THE NEW PHYTOLOGIST 2018; 219:947-958. [PMID: 28585237 DOI: 10.1111/nph.14633] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/27/2017] [Indexed: 05/25/2023]
Abstract
Drought disproportionately affects larger trees in tropical forests, but implications for forest composition and carbon (C) cycling in relation to dry season intensity remain poorly understood. In order to characterize how C cycling is shaped by tree size and drought adaptations and how these patterns relate to spatial and temporal variation in water deficit, we analyze data from three forest dynamics plots spanning a moisture gradient in Panama that have experienced El Niño droughts. At all sites, aboveground C cycle contributions peaked below 50-cm stem diameter, with stems ≥ 50 cm accounting for on average 59% of live aboveground biomass, 45% of woody productivity and 49% of woody mortality. The dominance of drought-avoidance strategies increased interactively with stem diameter and dry season intensity. Although size-related C cycle contributions did not vary systematically across the moisture gradient under nondrought conditions, woody mortality of larger trees was disproportionately elevated under El Niño drought stress. Thus, large (> 50 cm) stems, which strongly mediate but do not necessarily dominate C cycling, have drought adaptations that compensate for their more challenging hydraulic environment, particularly in drier climates. However, these adaptations do not fully buffer the effects of severe drought, and increased large tree mortality dominates ecosystem-level drought responses.
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Powell TL, Koven CD, Johnson DJ, Faybishenko B, Fisher RA, Knox RG, McDowell NG, Condit R, Hubbell SP, Wright SJ, Chambers JQ, Kueppers LM. Variation in hydroclimate sustains tropical forest biomass and promotes functional diversity. THE NEW PHYTOLOGIST 2018; 219:932-946. [PMID: 29923303 DOI: 10.1111/nph.15271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 05/13/2018] [Indexed: 06/08/2023]
Abstract
The fate of tropical forests under climate change is unclear as a result, in part, of the uncertainty in projected changes in precipitation and in the ability of vegetation models to capture the effects of drought-induced mortality on aboveground biomass (AGB). We evaluated the ability of a terrestrial biosphere model with demography and hydrodynamics (Ecosystem Demography, ED2-hydro) to simulate AGB and mortality of four tropical tree plant functional types (PFTs) that operate along light- and water-use axes. Model predictions were compared with observations of canopy trees at Barro Colorado Island (BCI), Panama. We then assessed the implications of eight hypothetical precipitation scenarios, including increased annual precipitation, reduced inter-annual variation, El Niño-related droughts and drier wet or dry seasons, on AGB and functional diversity of the model forest. When forced with observed meteorology, ED2-hydro predictions capture multiple BCI benchmarks. ED2-hydro predicts that AGB will be sustained under lower rainfall via shifts in the functional composition of the forest, except under the drier dry-season scenario. These results support the hypothesis that inter-annual variation in mean and seasonal precipitation promotes the coexistence of functionally diverse PFTs because of the relative differences in mortality rates. If the hydroclimate becomes chronically drier or wetter, functional evenness related to drought tolerance may decline.
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Dornelas M, Antão LH, Moyes F, Bates AE, Magurran AE, Adam D, Akhmetzhanova AA, Appeltans W, Arcos JM, Arnold H, Ayyappan N, Badihi G, Baird AH, Barbosa M, Barreto TE, Bässler C, Bellgrove A, Belmaker J, Benedetti‐Cecchi L, Bett BJ, Bjorkman AD, Błażewicz M, Blowes SA, Bloch CP, Bonebrake TC, Boyd S, Bradford M, Brooks AJ, Brown JH, Bruelheide H, Budy P, Carvalho F, Castañeda‐Moya E, Chen CA, Chamblee JF, Chase TJ, Siegwart Collier L, Collinge SK, Condit R, Cooper EJ, Cornelissen JHC, Cotano U, Kyle Crow S, Damasceno G, Davies CH, Davis RA, Day FP, Degraer S, Doherty TS, Dunn TE, Durigan G, Duffy JE, Edelist D, Edgar GJ, Elahi R, Elmendorf SC, Enemar A, Ernest SKM, Escribano R, Estiarte M, Evans BS, Fan T, Turini Farah F, Loureiro Fernandes L, Farneda FZ, Fidelis A, Fitt R, Fosaa AM, Daher Correa Franco GA, Frank GE, Fraser WR, García H, Cazzolla Gatti R, Givan O, Gorgone‐Barbosa E, Gould WA, Gries C, Grossman GD, Gutierréz JR, Hale S, Harmon ME, Harte J, Haskins G, Henshaw DL, Hermanutz L, Hidalgo P, Higuchi P, Hoey A, Van Hoey G, Hofgaard A, Holeck K, Hollister RD, Holmes R, Hoogenboom M, Hsieh C, Hubbell SP, Huettmann F, Huffard CL, Hurlbert AH, Macedo Ivanauskas N, Janík D, Jandt U, Jażdżewska A, Johannessen T, Johnstone J, Jones J, Jones FAM, Kang J, Kartawijaya T, Keeley EC, Kelt DA, Kinnear R, Klanderud K, Knutsen H, Koenig CC, Kortz AR, Král K, Kuhnz LA, Kuo C, Kushner DJ, Laguionie‐Marchais C, Lancaster LT, Min Lee C, Lefcheck JS, Lévesque E, Lightfoot D, Lloret F, Lloyd JD, López‐Baucells A, Louzao M, Madin JS, Magnússon B, Malamud S, Matthews I, McFarland KP, McGill B, McKnight D, McLarney WO, Meador J, Meserve PL, Metcalfe DJ, Meyer CFJ, Michelsen A, Milchakova N, Moens T, Moland E, Moore J, Mathias Moreira C, Müller J, Murphy G, Myers‐Smith IH, Myster RW, Naumov A, Neat F, Nelson JA, Paul Nelson M, Newton SF, Norden N, Oliver JC, Olsen EM, Onipchenko VG, Pabis K, Pabst RJ, Paquette A, Pardede S, Paterson DM, Pélissier R, Peñuelas J, Pérez‐Matus A, Pizarro O, Pomati F, Post E, Prins HHT, Priscu JC, Provoost P, Prudic KL, Pulliainen E, Ramesh BR, Mendivil Ramos O, Rassweiler A, Rebelo JE, Reed DC, Reich PB, Remillard SM, Richardson AJ, Richardson JP, van Rijn I, Rocha R, Rivera‐Monroy VH, Rixen C, Robinson KP, Ribeiro Rodrigues R, de Cerqueira Rossa‐Feres D, Rudstam L, Ruhl H, Ruz CS, Sampaio EM, Rybicki N, Rypel A, Sal S, Salgado B, Santos FAM, Savassi‐Coutinho AP, Scanga S, Schmidt J, Schooley R, Setiawan F, Shao K, Shaver GR, Sherman S, Sherry TW, Siciński J, Sievers C, da Silva AC, Rodrigues da Silva F, Silveira FL, Slingsby J, Smart T, Snell SJ, Soudzilovskaia NA, Souza GBG, Maluf Souza F, Castro Souza V, Stallings CD, Stanforth R, Stanley EH, Mauro Sterza J, Stevens M, Stuart‐Smith R, Rondon Suarez Y, Supp S, Yoshio Tamashiro J, Tarigan S, Thiede GP, Thorn S, Tolvanen A, Teresa Zugliani Toniato M, Totland Ø, Twilley RR, Vaitkus G, Valdivia N, Vallejo MI, Valone TJ, Van Colen C, Vanaverbeke J, Venturoli F, Verheye HM, Vianna M, Vieira RP, Vrška T, Quang Vu C, Van Vu L, Waide RB, Waldock C, Watts D, Webb S, Wesołowski T, White EP, Widdicombe CE, Wilgers D, Williams R, Williams SB, Williamson M, Willig MR, Willis TJ, Wipf S, Woods KD, Woehler EJ, Zawada K, Zettler ML, Hickler T. BioTIME: A database of biodiversity time series for the Anthropocene. GLOBAL ECOLOGY AND BIOGEOGRAPHY : A JOURNAL OF MACROECOLOGY 2018; 27:760-786. [PMID: 30147447 PMCID: PMC6099392 DOI: 10.1111/geb.12729] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 11/25/2017] [Accepted: 11/28/2017] [Indexed: 05/08/2023]
Abstract
MOTIVATION The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. MAIN TYPES OF VARIABLES INCLUDED The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. SPATIAL LOCATION AND GRAIN BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). TIME PERIOD AND GRAIN BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. MAJOR TAXA AND LEVEL OF MEASUREMENT BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates. SOFTWARE FORMAT .csv and .SQL.
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Johnson DJ, Condit R, Hubbell SP, Comita LS. Abiotic niche partitioning and negative density dependence drive tree seedling survival in a tropical forest. Proc Biol Sci 2018; 284:rspb.2017.2210. [PMID: 29237862 DOI: 10.1098/rspb.2017.2210] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/14/2017] [Indexed: 11/12/2022] Open
Abstract
In tropical tree communities, processes occurring during early life stages play a critical role in shaping forest composition and diversity through differences in species' performance. Predicting the future of tropical forests depends on a solid understanding of the drivers of seedling survival. At the same time, factors determining spatial and temporal patterns of seedling survival can play a large role in permitting species coexistence in diverse communities. Using long-term data on the survival of more than 45 000 seedlings of 238 species in a Neotropical forest, we assessed the relative importance of key abiotic and biotic neighbourhood variables thought to influence individual seedling survival and tested whether species vary significantly in their responses to these variables, consistent with niche differences. At the community level, seedling survival was significantly correlated with plant size, topographic habitat, neighbourhood densities of conspecific seedlings, conspecific and heterospecific trees and annual variation in water availability, in descending order of effect size. Additionally, we found significant variation among species in their sensitivity to light and water availability, as well as in their survival within different topographic habitats, indicating the potential for niche differentiation among species that could allow for species coexistence.
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LaManna JA, Mangan SA, Alonso A, Bourg NA, Brockelman WY, Bunyavejchewin S, Chang LW, Chiang JM, Chuyong GB, Clay K, Cordell S, Davies SJ, Furniss TJ, Giardina CP, Gunatilleke IAUN, Gunatilleke CVS, He F, Howe RW, Hubbell SP, Hsieh CF, Inman-Narahari FM, Janík D, Johnson DJ, Kenfack D, Korte L, Král K, Larson AJ, Lutz JA, McMahon SM, McShea WJ, Memiaghe HR, Nathalang A, Novotny V, Ong PS, Orwig DA, Ostertag R, Parker GG, Phillips RP, Sack L, Sun IF, Tello JS, Thomas DW, Turner BL, Vela Díaz DM, Vrška T, Weiblen GD, Wolf A, Yap S, Myers JA. Response to Comment on "Plant diversity increases with the strength of negative density dependence at the global scale". Science 2018; 360:360/6391/eaar3824. [PMID: 29798853 DOI: 10.1126/science.aar3824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 04/18/2018] [Indexed: 11/02/2022]
Abstract
Hülsmann and Hartig suggest that ecological mechanisms other than specialized natural enemies or intraspecific competition contribute to our estimates of conspecific negative density dependence (CNDD). To address their concern, we show that our results are not the result of a methodological artifact and present a null-model analysis that demonstrates that our original findings-(i) stronger CNDD at tropical relative to temperate latitudes and (ii) a latitudinal shift in the relationship between CNDD and species abundance-persist even after controlling for other processes that might influence spatial relationships between adults and recruits.
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LaManna JA, Mangan SA, Alonso A, Bourg NA, Brockelman WY, Bunyavejchewin S, Chang LW, Chiang JM, Chuyong GB, Clay K, Cordell S, Davies SJ, Furniss TJ, Giardina CP, Gunatilleke IAUN, Gunatilleke CVS, He F, Howe RW, Hubbell SP, Hsieh CF, Inman-Narahari FM, Janík D, Johnson DJ, Kenfack D, Korte L, Král K, Larson AJ, Lutz JA, McMahon SM, McShea WJ, Memiaghe HR, Nathalang A, Novotny V, Ong PS, Orwig DA, Ostertag R, Parker GG, Phillips RP, Sack L, Sun IF, Tello JS, Thomas DW, Turner BL, Vela Díaz DM, Vrška T, Weiblen GD, Wolf A, Yap S, Myers JA. Response to Comment on “Plant diversity increases with the strength of negative density dependence at the global scale”. Science 2018; 360:360/6391/eaar5245. [DOI: 10.1126/science.aar5245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 04/18/2018] [Indexed: 11/02/2022]
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LaManna JA, Mangan SA, Alonso A, Bourg NA, Brockelman WY, Bunyavejchewin S, Chang LW, Chiang JM, Chuyong GB, Clay K, Condit R, Cordell S, Davies SJ, Furniss TJ, Giardina CP, Gunatilleke IAUN, Gunatilleke CVS, He F, Howe RW, Hubbell SP, Hsieh CF, Inman-Narahari FM, Janík D, Johnson DJ, Kenfack D, Korte L, Král K, Larson AJ, Lutz JA, McMahon SM, McShea WJ, Memiaghe HR, Nathalang A, Novotny V, Ong PS, Orwig DA, Ostertag R, Parker GG, Phillips RP, Sack L, Sun IF, Tello JS, Thomas DW, Turner BL, Vela Díaz DM, Vrška T, Weiblen GD, Wolf A, Yap S, Myers JA. Plant diversity increases with the strength of negative density dependence at the global scale. Science 2018; 356:1389-1392. [PMID: 28663501 DOI: 10.1126/science.aam5678] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/14/2017] [Accepted: 05/16/2017] [Indexed: 01/24/2023]
Abstract
Theory predicts that higher biodiversity in the tropics is maintained by specialized interactions among plants and their natural enemies that result in conspecific negative density dependence (CNDD). By using more than 3000 species and nearly 2.4 million trees across 24 forest plots worldwide, we show that global patterns in tree species diversity reflect not only stronger CNDD at tropical versus temperate latitudes but also a latitudinal shift in the relationship between CNDD and species abundance. CNDD was stronger for rare species at tropical versus temperate latitudes, potentially causing the persistence of greater numbers of rare species in the tropics. Our study reveals fundamental differences in the nature of local-scale biotic interactions that contribute to the maintenance of species diversity across temperate and tropical communities.
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McNickle GG, Lamb EG, Lavender M, Cahill JF, Schamp BS, Siciliano SD, Condit R, Hubbell SP, Baltzer JL. Checkerboard score-area relationships reveal spatial scales of plant community structure. OIKOS 2017. [DOI: 10.1111/oik.04620] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kellner JR, Hubbell SP. Adult mortality in a low-density tree population using high-resolution remote sensing. Ecology 2017; 98:1700-1709. [PMID: 28376234 DOI: 10.1002/ecy.1847] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/06/2017] [Accepted: 03/10/2017] [Indexed: 11/07/2022]
Abstract
We developed a statistical framework to quantify mortality rates in canopy trees observed using time series from high-resolution remote sensing. By timing the acquisition of remote sensing data with synchronous annual flowering in the canopy tree species Handroanthus guayacan, we made 2,596 unique detections of 1,006 individual adult trees within 18,883 observation attempts on Barro Colorado Island, Panama (BCI) during an 11-yr period. There were 1,057 observation attempts that resulted in missing data due to cloud cover or incomplete spatial coverage. Using the fraction of 123 individuals from an independent field sample that were detected by satellite data (109 individuals, 88.6%), we estimate that the adult population for this species on BCI was 1,135 individuals. We used a Bayesian state-space model that explicitly accounted for the probability of tree detection and missing observations to compute an annual adult mortality rate of 0.2%·yr-1 (SE = 0.1, 95% CI = 0.06-0.45). An independent estimate of the adult mortality rate from 260 field-checked trees closely matched the landscape-scale estimate (0.33%·yr-1 , SE = 0.16, 95% CI = 0.12-0.74). Our proof-of-concept study shows that one can remotely estimate adult mortality rates for canopy tree species precisely in the presence of variable detection and missing observations.
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Sugiyama A, Shichi K, Masaki T, Hubbell SP. The use of soil pollen to determine the sex of overhead individuals of a temperate dioecious shrub. AMERICAN JOURNAL OF BOTANY 2017; 104:632-638. [PMID: 28424205 DOI: 10.3732/ajb.1600407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/17/2017] [Indexed: 06/07/2023]
Abstract
PREMISE OF THE STUDY In dioecious species, determining the sex of individual plants from one-time phenological observations is rarely feasible when some individuals capable of reproducing are not flowering or fruiting at the time of observation. Currently, sexing those individuals requires long-term phenological data on individuals and populations, but such data are rarely available or feasible to collect. We tested the hypothesis that differences in soil pollen concentrations beneath the crowns of female and male plants would exist and be sufficient to reliably determine the sex of the individual plant overhead in a dioecious species. We predicted that soil pollen concentrations beneath male plants would be significantly higher than beneath female plants because only males produce pollen and pollen should accumulate in the soil underneath the male plants over repeated flowering events. METHODS We collected samples from surface soil under both sexes of the insect-pollinated dioecious shrub, Aucuba japonica (Garryaceae). KEY RESULTS Pollen grains were present in surface soil in both Oe and A horizons, and mean pollen concentration under males was significantly higher than under females. Pollen concentrations beneath males were positively correlated with male plant height, potentially reflecting greater pollen production by larger individuals. CONCLUSIONS Considering the small plant size and relatively low pollen production of A. japonica, this method may hold promise for sexing other dioecious species in the absence of direct phenological data. Our phenology-free and relatively low-cost method for sexing dioecious plants may be especially useful in tropical forests where many species are dioecious.
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Bruijning M, Visser MD, Muller-Landau HC, Wright SJ, Comita LS, Hubbell SP, de Kroon H, Jongejans E. Surviving in a Cosexual World: A Cost-Benefit Analysis of Dioecy in Tropical Trees. Am Nat 2017; 189:297-314. [PMID: 28221824 DOI: 10.1086/690137] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Dioecy has a demographic disadvantage compared with hermaphroditism: only about half of reproductive adults produce seeds. Dioecious species must therefore have fitness advantages to compensate for this cost through increased survival, growth, and/or reproduction. We used a full life cycle approach to quantify the demographic costs and benefits associated with dioecy while controlling for demographic differences between dioecious and hermaphroditic species related to other functional traits. The advantage of this novel approach is that we can focus on the effect of breeding system across a diverse tree community. We built a composite integral projection model for hermaphroditic and dioecious tree populations from Barro Colorado Island, Panama, using long-term demographic and newly collected reproductive data. Integration of all costs and benefits showed that compensation was realized through increased seed production, resulting in no net costs of dioecy. Compensation was also facilitated by the low contribution of reproduction to population growth. Estimated positive effects of dioecy on tree growth and survival were small and insignificant for population growth rates. Our model revealed that, for long-lived organisms, the cost of having males is smaller than generally expected. Hence, little compensation is required for dioecious species to maintain population growth rates similar to those of hermaphroditic species.
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Wills C, Harms KE, Wiegand T, Punchi-Manage R, Gilbert GS, Erickson D, Kress WJ, Hubbell SP, Gunatilleke CVS, Gunatilleke IAUN. Correction: Persistence of Neighborhood Demographic Influences over Long Phylogenetic Distances May Help Drive Post-Speciation Adaptation in Tropical Forests. PLoS One 2016; 11:e0168976. [PMID: 27997606 PMCID: PMC5173372 DOI: 10.1371/journal.pone.0168976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Gilbert GS, Ballesteros JO, Barrios-Rodriguez CA, Bonadies EF, Cedeño-Sánchez ML, Fossatti-Caballero NJ, Trejos-Rodríguez MM, Pérez-Suñiga JM, Holub-Young KS, Henn LAW, Thompson JB, García-López CG, Romo AC, Johnston DC, Barrick PP, Jordan FA, Hershcovich S, Russo N, Sánchez JD, Fábrega JP, Lumpkin R, McWilliams HA, Chester KN, Burgos AC, Wong EB, Diab JH, Renteria SA, Harrower JT, Hooton DA, Glenn TC, Faircloth BC, Hubbell SP. Use of sonic tomography to detect and quantify wood decay in living trees. APPLICATIONS IN PLANT SCIENCES 2016; 4:apps1600060. [PMID: 28101433 PMCID: PMC5238698 DOI: 10.3732/apps.1600060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/26/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY Field methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes. METHODS AND RESULTS Living trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness. CONCLUSIONS Sonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees.
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Chen Y, Wright SJ, Muller-Landau HC, Hubbell SP, Wang Y, Yu S. Positive effects of neighborhood complementarity on tree growth in a Neotropical forest. Ecology 2016; 97:776-85. [PMID: 27197403 DOI: 10.1890/15-0625.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Numerous grassland experiments have found evidence for a complementarity effect, an increase in productivity with higher plant species richness due to niche partitioning. However, empirical tests of complementarity in natural forests are rare. We conducted a spatially explicit analysis of 518 433 growth records for 274 species from a 50-ha tropical forest plot to test neighborhood complementarity, the idea that a tree grows faster when it is surrounded by more dissimilar neighbors. We found evidence for complementarity: focal tree growth rates increased by 39.8% and 34.2% with a doubling of neighborhood multi-trait dissimilarity and phylogenetic dissimilarity, respectively. Dissimilarity from neighbors in maximum height had the most important effect on tree growth among the six traits examined, and indeed, its effect trended much larger than that of the multitrait dissimilarity index. Neighborhood complementarity effects were strongest for light-demanding species, and decreased in importance with increasing shade tolerance of the focal individuals. Simulations demonstrated that the observed neighborhood complementarities were sufficient to produce positive stand-level biodiversity-productivity relationships. We conclude that neighborhood complementarity is important for productivity in this tropical forest, and that scaling down to individual-level processes can advance our understanding of the mechanisms underlying stand-level biodiversity-productivity relationships.
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Getzin S, Wiegand T, Hubbell SP. Stochastically driven adult-recruit associations of tree species on Barro Colorado Island. Proc Biol Sci 2015; 281:rspb.2014.0922. [PMID: 25030984 PMCID: PMC4123702 DOI: 10.1098/rspb.2014.0922] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The spatial placement of recruits around adult conspecifics represents the accumulated outcome of several pattern-forming processes and mechanisms such as primary and secondary seed dispersal, habitat associations or Janzen–Connell effects. Studying the adult–recruit relationship should therefore allow the derivation of specific hypotheses on the processes shaping population and community dynamics. We analysed adult–recruit associations for 65 tree species taken from six censuses of the 50 ha neotropical forest plot on Barro Colorado Island (BCI), Panama. We used point pattern analysis to test, at a range of neighbourhood scales, for spatial independence between recruits and adults, to assess the strength and type of departure from independence, and its relationship with species properties. Positive associations expected to prevail due to dispersal limitation occurred only in 16% of all cases; instead a majority of species showed spatial independence (≈73%). Independence described the placement of recruits around conspecific adults in good approximation, although we found weak and noisy signals of species properties related to seed dispersal. We hypothesize that spatial mechanisms with strong stochastic components such as animal seed dispersal overpower the pattern-forming effects of dispersal limitation, density dependence and habitat association, or that some of the pattern-forming processes cancel out each other.
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Barberán A, McGuire KL, Wolf JA, Jones FA, Wright SJ, Turner BL, Essene A, Hubbell SP, Faircloth BC, Fierer N. Relating belowground microbial composition to the taxonomic, phylogenetic, and functional trait distributions of trees in a tropical forest. Ecol Lett 2015; 18:1397-405. [PMID: 26472095 DOI: 10.1111/ele.12536] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/25/2015] [Accepted: 09/23/2015] [Indexed: 12/17/2022]
Abstract
The complexities of the relationships between plant and soil microbial communities remain unresolved. We determined the associations between plant aboveground and belowground (root) distributions and the communities of soil fungi and bacteria found across a diverse tropical forest plot. Soil microbial community composition was correlated with the taxonomic and phylogenetic structure of the aboveground plant assemblages even after controlling for differences in soil characteristics, but these relationships were stronger for fungi than for bacteria. In contrast to expectations, the species composition of roots in our soil core samples was a poor predictor of microbial community composition perhaps due to the patchy, ephemeral, and highly overlapping nature of fine root distributions. Our ability to predict soil microbial composition was not improved by incorporating information on plant functional traits suggesting that the most commonly measured plant traits are not particularly useful for predicting the plot-level variability in belowground microbial communities.
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Wolf JA, Hubbell SP, Fricker GA, Turner BL. Geospatial observations on tropical forest surface soil chemistry. Ecology 2015. [DOI: 10.1890/15-0558.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Hubbell SP. Estimating the global number of tropical tree species, and Fisher's paradox. Proc Natl Acad Sci U S A 2015; 112:7343-4. [PMID: 26056305 PMCID: PMC4475976 DOI: 10.1073/pnas.1507730112] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Anderson-Teixeira KJ, Davies SJ, Bennett AC, Gonzalez-Akre EB, Muller-Landau HC, Wright SJ, Abu Salim K, Almeyda Zambrano AM, Alonso A, Baltzer JL, Basset Y, Bourg NA, Broadbent EN, Brockelman WY, Bunyavejchewin S, Burslem DFRP, Butt N, Cao M, Cardenas D, Chuyong GB, Clay K, Cordell S, Dattaraja HS, Deng X, Detto M, Du X, Duque A, Erikson DL, Ewango CEN, Fischer GA, Fletcher C, Foster RB, Giardina CP, Gilbert GS, Gunatilleke N, Gunatilleke S, Hao Z, Hargrove WW, Hart TB, Hau BCH, He F, Hoffman FM, Howe RW, Hubbell SP, Inman-Narahari FM, Jansen PA, Jiang M, Johnson DJ, Kanzaki M, Kassim AR, Kenfack D, Kibet S, Kinnaird MF, Korte L, Kral K, Kumar J, Larson AJ, Li Y, Li X, Liu S, Lum SKY, Lutz JA, Ma K, Maddalena DM, Makana JR, Malhi Y, Marthews T, Mat Serudin R, McMahon SM, McShea WJ, Memiaghe HR, Mi X, Mizuno T, Morecroft M, Myers JA, Novotny V, de Oliveira AA, Ong PS, Orwig DA, Ostertag R, den Ouden J, Parker GG, Phillips RP, Sack L, Sainge MN, Sang W, Sri-Ngernyuang K, Sukumar R, Sun IF, Sungpalee W, Suresh HS, Tan S, Thomas SC, Thomas DW, Thompson J, Turner BL, Uriarte M, Valencia R, Vallejo MI, Vicentini A, Vrška T, Wang X, Wang X, Weiblen G, Wolf A, Xu H, Yap S, Zimmerman J. CTFS-ForestGEO: a worldwide network monitoring forests in an era of global change. GLOBAL CHANGE BIOLOGY 2015; 21:528-49. [PMID: 25258024 DOI: 10.1111/gcb.12712] [Citation(s) in RCA: 267] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/06/2014] [Indexed: 05/10/2023]
Abstract
Global change is impacting forests worldwide, threatening biodiversity and ecosystem services including climate regulation. Understanding how forests respond is critical to forest conservation and climate protection. This review describes an international network of 59 long-term forest dynamics research sites (CTFS-ForestGEO) useful for characterizing forest responses to global change. Within very large plots (median size 25 ha), all stems ≥ 1 cm diameter are identified to species, mapped, and regularly recensused according to standardized protocols. CTFS-ForestGEO spans 25 °S-61 °N latitude, is generally representative of the range of bioclimatic, edaphic, and topographic conditions experienced by forests worldwide, and is the only forest monitoring network that applies a standardized protocol to each of the world's major forest biomes. Supplementary standardized measurements at subsets of the sites provide additional information on plants, animals, and ecosystem and environmental variables. CTFS-ForestGEO sites are experiencing multifaceted anthropogenic global change pressures including warming (average 0.61 °C), changes in precipitation (up to ± 30% change), atmospheric deposition of nitrogen and sulfur compounds (up to 3.8 g N m(-2) yr(-1) and 3.1 g S m(-2) yr(-1)), and forest fragmentation in the surrounding landscape (up to 88% reduced tree cover within 5 km). The broad suite of measurements made at CTFS-ForestGEO sites makes it possible to investigate the complex ways in which global change is impacting forest dynamics. Ongoing research across the CTFS-ForestGEO network is yielding insights into how and why the forests are changing, and continued monitoring will provide vital contributions to understanding worldwide forest diversity and dynamics in an era of global change.
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Inman-Narahari F, Ostertag R, Asner GP, Cordell S, Hubbell SP, Sack L. Trade-offs in seedling growth and survival within and across tropical forest microhabitats. Ecol Evol 2014; 4:3755-67. [PMID: 25614790 PMCID: PMC4301042 DOI: 10.1002/ece3.1196] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/04/2014] [Accepted: 07/13/2014] [Indexed: 11/09/2022] Open
Abstract
For niche differences to maintain coexistence of sympatric species, each species must grow and/or survive better than each of the others in at least one set of conditions (i.e., performance trade-offs). However, the extent of niche differentiation in tropical forests remains highly debated. We present the first test of performance trade-offs for wild seedlings in a tropical forest. We measured seedling relative growth rate (RGR) and survival of four common native woody species across 18 light, substrate, and topography microhabitats over 2.5 years within Hawaiian montane wet forest, an ideal location due to its low species diversity and strong species habitat associations. All six species pairs exhibited significant performance trade-offs across microhabitats and for RGR versus survival within microhabitats. We also found some evidence of performance equivalence, with species pairs having similar performance in 26% of comparisons across microhabitats. Across species, survival under low light was generally positively associated with RGR under high light. When averaged over all species, topography (slope, aspect, and elevation) explained most of the variation in RGR attributable to microhabitat variables (51-53%) followed by substrate type (35-37%) and light (11-12%). However, the relative effects of microhabitat differed among species and RGR metric (i.e., RGR for height, biomass, or leaf area). These findings indicate that performance trade-offs among species during regeneration are common in low-diversity tropical forest, although other mechanisms may better explain the coexistence of species with small performance differences.
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Cushman KC, Muller-Landau HC, Condit RS, Hubbell SP. Improving estimates of biomass change in buttressed trees using tree taper models. Methods Ecol Evol 2014. [DOI: 10.1111/2041-210x.12187] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Baldeck CA, Harms KE, Yavitt JB, John R, Turner BL, Valencia R, Navarrete H, Bunyavejchewin S, Kiratiprayoon S, Yaacob A, Supardi MNN, Davies SJ, Hubbell SP, Chuyong GB, Kenfack D, Thomas DW, Dalling JW. Habitat filtering across tree life stages in tropical forest communities. Proc Biol Sci 2013; 280:20130548. [PMID: 23843384 PMCID: PMC3730581 DOI: 10.1098/rspb.2013.0548] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/14/2013] [Indexed: 11/12/2022] Open
Abstract
Tropical tree communities are shaped by local-scale habitat heterogeneity in the form of topographic and edaphic variation, but the life-history stage at which habitat associations develop remains poorly understood. This is due, in part, to the fact that previous studies have not accounted for the widely disparate sample sizes (number of stems) that result when trees are divided into size classes. We demonstrate that the observed habitat structuring of a community is directly related to the number of individuals in the community. We then compare the relative importance of habitat heterogeneity to tree community structure for saplings, juveniles and adult trees within seven large (24-50 ha) tropical forest dynamics plots while controlling for sample size. Changes in habitat structuring through tree life stages were small and inconsistent among life stages and study sites. Where found, these differences were an order of magnitude smaller than the findings of previous studies that did not control for sample size. Moreover, community structure and composition were very similar among tree sub-communities of different life stages. We conclude that the structure of these tropical tree communities is established by the time trees are large enough to be included in the census (1 cm diameter at breast height), which indicates that habitat filtering occurs during earlier life stages.
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Hubbell SP. Tropical rain forest conservation and the twin challenges of diversity and rarity. Ecol Evol 2013; 3:3263-74. [PMID: 24223266 PMCID: PMC3797475 DOI: 10.1002/ece3.705] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/29/2013] [Accepted: 07/01/2013] [Indexed: 11/06/2022] Open
Abstract
Data from a global network of large, permanent plots in lowland tropical forests demonstrate (1) that the phenomenon of tropical tree rarity is real and (2) that almost all the species diversity in such forests is due to rare species. Theoretical and empirically based reasoning suggests that many of these rare species are not as geographically widespread as previously thought. These findings suggest that successful strategies for conserving global tree diversity in lowland tropical forests must pay much more attention to the biogeography of rarity, as well as to the impact of climate change on the distribution and abundance of rare species. Because the biogeography of many tropical tree species is poorly known, a high priority should be given to documenting the distribution and abundance of rare tropical tree species, particularly in Amazonia, the largest remaining tropical forested region in the world.
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Baldeck CA, Kembel SW, Harms KE, Yavitt JB, John R, Turner BL, Chuyong GB, Kenfack D, Thomas DW, Madawala S, Gunatilleke N, Gunatilleke S, Bunyavejchewin S, Kiratiprayoon S, Yaacob A, Nur Supardi MN, Valencia R, Navarrete H, Davies SJ, Hubbell SP, Dalling JW. A taxonomic comparison of local habitat niches of tropical trees. Oecologia 2013; 173:1491-8. [PMID: 23851985 DOI: 10.1007/s00442-013-2709-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/06/2013] [Indexed: 10/26/2022]
Abstract
The integration of ecology and evolutionary biology requires an understanding of the evolutionary lability in species' ecological niches. For tropical trees, specialization for particular soil resource and topographic conditions is an important part of the habitat niche, influencing the distributions of individual species and overall tree community structure at the local scale. However, little is known about how these habitat niches are related to the evolutionary history of species. We assessed the relationship between taxonomic rank and tree species' soil resource and topographic niches in eight large (24-50 ha) tropical forest dynamics plots. Niche overlap values, indicating the similarity of two species' distributions along soil or topographic axes, were calculated for all pairwise combinations of co-occurring tree species at each study site. Congeneric species pairs often showed greater niche overlap (i.e., more similar niches) than non-congeneric pairs along both soil and topographic axes, though significant effects were found for only five sites based on Mantel tests. No evidence for taxonomic effects was found at the family level. Our results indicate that local habitat niches of trees exhibit varying degrees of phylogenetic signal at different sites, which may have important ramifications for the phylogenetic structure of these communities.
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Schnitzer SA, Mangan SA, Dalling JW, Baldeck CA, Hubbell SP, Ledo A, Muller-Landau H, Tobin MF, Aguilar S, Brassfield D, Hernandez A, Lao S, Perez R, Valdes O, Yorke SR. Liana abundance, diversity, and distribution on Barro Colorado Island, Panama. PLoS One 2012; 7:e52114. [PMID: 23284889 PMCID: PMC3528767 DOI: 10.1371/journal.pone.0052114] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 11/14/2012] [Indexed: 11/20/2022] Open
Abstract
Lianas are a key component of tropical forests; however, most surveys are too small to accurately quantify liana community composition, diversity, abundance, and spatial distribution - critical components for measuring the contribution of lianas to forest processes. In 2007, we tagged, mapped, measured the diameter, and identified all lianas ≥1 cm rooted in a 50-ha plot on Barro Colorado Island, Panama (BCI). We calculated liana density, basal area, and species richness for both independently rooted lianas and all rooted liana stems (genets plus clones). We compared spatial aggregation patterns of liana and tree species, and among liana species that varied in the amount of clonal reproduction. We also tested whether liana and tree densities have increased on BCI compared to surveys conducted 30-years earlier. This study represents the most comprehensive spatially contiguous sampling of lianas ever conducted and, over the 50 ha area, we found 67,447 rooted liana stems comprising 162 species. Rooted lianas composed nearly 25% of the woody stems (trees and lianas), 35% of woody species richness, and 3% of woody basal area. Lianas were spatially aggregated within the 50-ha plot and the liana species with the highest proportion of clonal stems more spatially aggregated than the least clonal species, possibly indicating clonal stem recruitment following canopy disturbance. Over the past 30 years, liana density increased by 75% for stems ≥1 cm diameter and nearly 140% for stems ≥5 cm diameter, while tree density on BCI decreased 11.5%; a finding consistent with other neotropical forests. Our data confirm that lianas contribute substantially to tropical forest stem density and diversity, they have highly clumped distributions that appear to be driven by clonal stem recruitment into treefall gaps, and they are increasing relative to trees, thus indicating that lianas will play a greater role in the future dynamics of BCI and other neotropical forests.
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