Giants of the Amazon: How does environmental variation drive the diversity patterns of large trees?
Robson Borges de LimaEric Bastos GörgensDiego Armando S da SilvaCinthia Pereira de OliveiraAnderson Pedro B BatistaRinaldo Luiz Caraciolo FerreiraFlavia R C CostaRenato A Ferreira de LimaPerseu da Silva AparícioJadson Coelho de AbreuJosé Antônio Aleixo da SilvaAretha Franklin GuimaraesPhilip Martin FearnsideThaiane R SousaRicardo PerdizNiro HiguchiErika BerenguerAngélica F ResendeFernando EliasCarolina Volkmer de CastilhoMarcelo Brilhante de MedeirosJoão Ramos de Matos FilhoMaurício Alves SardinhaMárcio André Furtado FreitasJosé Jussian da SilvaAldemir Pereira da CunhaRenan Mendes SantosAdriane Esquivel MuelbertMarcelino Carneiro GuedesReinaldo Imbrozio BarbosaCarla Samara Campelo de SousaWegliane Campelo da Silva AparícioBreno Marques da Silva E SilvaCelice Alexandre SilvaBeatriz Schwantes MarimonBen Hur Marimon JuniorPaulo S MorandiDanielle Storck-TononIma Célia Guimarães VieiraJuliana SchiettiFernanda CoelhoDanilo R Alves de AlmeidaWendeson CastroSamuel P C CarvalhoRobson Dos Santos A da SilvaJuliana SilveiraJosé Luís CamargoKarina MelgaçoLucas Jose Mazzei de FreitasLaura VedovatoMaíra BenchimolGabriel de Oliveira de AlmeidaGhillean PranceAlan Bernardes da SilveiraMarcelo Fragomeni SimonMarcos Leandro GarciaMarcos SilveiraMarcos VitalMaryane B T AndradeNatalino SilvaRaimunda Oliveira de AraújoLarissa CavalheiroRainiellen CarpanedoLetícia FernandesAngelo Gilberto ManzattoRicardo T G de AndradeWilliam E MagnussonBill LauranceBruce Walker NelsonCarlos Augusto PeresDouglas C DalyDomingos RodriguesAna Paula ZopelettoEdmar Almeida de OliveiraEstelle DugachardFlávia Rodrigues BarbosaFlavia SantanaIêda Leão do AmaralLeandro V FerreiraLeandro S CharãoJoice FerreiraJos BarlowLilian BlancLuiz Eduardo Oliveira E Cruz de AragãoPlinio SistRafael de Paiva SalomãoAntônio Sérgio Lima da SilvaSusan G W LauranceTed R FeldpauschToby GardnerWagner SantiagoWilliam BaleeWilliam F LauranceYadvinder MalhiOliver L PhillipsPublished in: Global change biology (2023)
For more than three decades, major efforts in sampling and analyzing tree diversity in South America have focused almost exclusively on trees with stems of at least 10 and 2.5 cm diameter, showing highest species diversity in the wetter western and northern Amazon forests. By contrast, little attention has been paid to patterns and drivers of diversity in the largest canopy and emergent trees, which is surprising given these have dominant ecological functions. Here, we use a machine learning approach to quantify the importance of environmental factors and apply it to generate spatial predictions of the species diversity of all trees (dbh ≥ 10 cm) and for very large trees (dbh ≥ 70 cm) using data from 243 forest plots (108,450 trees and 2832 species) distributed across different forest types and biogeographic regions of the Brazilian Amazon. The diversity of large trees and of all trees was significantly associated with three environmental factors, but in contrasting ways across regions and forest types. Environmental variables associated with disturbances, for example, the lightning flash rate and wind speed, as well as the fraction of photosynthetically active radiation, tend to govern the diversity of large trees. Upland rainforests in the Guiana Shield and Roraima regions had a high diversity of large trees. By contrast, variables associated with resources tend to govern tree diversity in general. Places such as the province of Imeri and the northern portion of the province of Madeira stand out for their high diversity of species in general. Climatic and topographic stability and functional adaptation mechanisms promote ideal conditions for species diversity. Finally, we mapped general patterns of tree species diversity in the Brazilian Amazon, which differ substantially depending on size class.