RESUMO
Climbers germinate on the ground but need external support to sustain their stems, which are maintained attached to supports through modified organs, that is, climbing mechanisms. Specialized climbing mechanisms have been linked to higher diversification rates. Also, different mechanisms may have different support diameter restrictions, which might influence climbers' spatial distribution. We test these assumptions by linking climbing mechanisms to the spatiotemporal diversification of neotropical climbers. A dataset of climbing mechanisms is presented for 9071 species. WCVP was used to standardize species names, map geographical distributions, and estimate diversification rates of lineages with different mechanisms. Twiners appear concentrated in the Dry Diagonal of South America and climbers with adhesive roots in the Chocó region and Central America. However, climbing mechanisms do not significantly influence the distribution of neotropical climbers. Also, we found no strong support for correlations between specialized climbing mechanisms and higher diversification rates. Climbing mechanisms do not strongly impact the spatiotemporal diversification of neotropical climbers on a macroevolutionary scale. We argue that the climbing habit is a synnovation, meaning the spatiotemporal diversification it promotes is due to the sum effect of all the habit's traits rather than isolated traits, such as climbing mechanisms.
Assuntos
Raízes de Plantas , América do Sul , Fenótipo , América CentralRESUMO
Climbing plants are remarkable components of forests, highly contributing for the diversity and dynamics of communities. Studies focusing on climbing plants are scarce and for many vegetation types little is known about climbing species composition and their traits relevant for dispersal and establishment. The focus of this study is to provide the first floristic inventory of climbing plants in an Araucaria forest of Brazil, describing the dispersal syndromes and climbing mechanisms of species and comparing these traits and species composition patterns with other study sites in Southern Brazil. We found 104 taxa belonging to 33 families, with Asteraceae (22 spp.) and Apocynaceae (14 spp.) being the richest families. Among climbing mechanisms, stem twiner (50 spp.) is the most common, followed by tendril (20 spp.) and scrambler (12 spp.), while in relation to the dispersal syndromes, anemochoric species (65 spp.) are the most relevant followed by endozoochoric (28 spp.). Three new species registries were found for Rio Grande do Sul State expanding their occurrence range towards South Brazil. The comparison of climbers' survey sites showed two sharp groups in relation to species composition and traits proportion, Seasonal and Araucaria/Atlantic forest sites, but with no difference of traits frequency between sites. There is a predominance of stem twiners species in all sites, but the relative difference for tendril species increases in Araucaria and Atlantic forest sites. The Asteraceae and Apocynaceae families were the most relevant, contrasting to Seasonal forests of Southeast Brazil. Interesting patterns can be achieved with a more detailed classification of climbing mechanisms and the results found in this study contributes to enhance the knowledge on climbers' traits and diversity in South Brazil.
Trepadeiras são importantes componentes florestais, contribuindo na diversidade e dinâmica de comunidades vegetais. Estudos focados em trepadeiras são escassos e para muitos tipos vegetacionais pouco se sabe sobre a composição de espécies de trepadeiras e seus atributos relevantes para dispersão e estabelecimento. O foco deste estudo é fornecer o primeiro inventário florístico de plantas trepadeiras em uma floresta de Araucária no Brasil, descrevendo as síndromes de dispersão e mecanismos de escalada das espécies e comparando esses atributos e a composição de espécies com outros sítios no Sul do Brasil. Foram encontrados 104 taxa pertencentes a 33 famílias, sendo Asteraceae (22 spp.) e Apocynaceae (14 spp.) as famílias mais ricas. Dentre os mecanismos de escalada, o tipo volúvel (50 spp.) é o mais comum, seguido por gavinhas (20 spp.) e apoiantes (12 spp.), enquanto em relação ès síndromes de dispersão as espécies anemocóricas (65 spp.) são as mais relevantes seguidas por endozoocóricas (28 spp.). Três novos registros de espécies foram encontrados para o Estado do Rio Grande do Sul, expandindo suas extensões de ocorrência para o Sul do Brasil. A comparação entre sítios evidenciou dois grupos nítidos em relação è composição de espécies e proporção de atributos, sítios em florestas sazonais e nas florestas com Araucária e Atlântica, porém não há diferença na frequência dos atributos entre os sítios. Há uma predominância de espécies volúveis em todos os sítios, entretanto a diferença relativa para espécies com gavinhas aumenta nos sítios de floresta com Araucária e Atlântica. As famílias Asteraceae e Apocynaceae foram as mais relevantes, contrastando com florestas sazonais no Sudeste do Brasil. Padrões interessantes podem ser encontrados com uma classificação mais detalhada dos mecanismos de escalada e os resultados encontrados neste estudo contribuem para aumentar o conhecimento sobre os atributos e a diversidade de trepadeiras no Sul do Brasil.