Dispersal spectrum of four forest types along an altitudinal range of the Brazilian Atlantic Rainforest

Abstract

In ecological communities, the proportion of plant species with different dispersal syndromes is known as the dispersal spectrum, which can result from different selective pressures such as climate. This is because variations in temperature, humidity, atmospheric pressure and precipitation result in distinct flora and fauna among different sites. If climate conditions along an altitudinal range act as a strong direct or indirect selective pressure on dispersal syndromes, the dispersal spectrum among plant communities in different altitudes should be distinct. We organized the dispersal syndromes in five hierarchical levels according to the levels of detail in diaspore morphology and, consequently, different degrees of specificity to the dispersers. Then we identified, within each hierarchical level, the syndromes of tree species of four forest types of the Atlantic Rainforest along a 1200 m altitudinal range in Southeast Brazil. Among 327 species, we found two syndromes in the most general hierarchical level (abiotic and biotic dispersal), three in the following level (wind, self and animal), three in the intermediate level (barochory, autochory and endozoochory), two in the forth level (mammal and bird), and 12 syndromes in the most specific level, all of which were related to the morphology of diaspores dispersed by wind, autochory, mammals and birds. The dispersal spectrum in the five hierarchical levels was similar among the four forest types. Overall, the majority of species is dispersed by biotic agents, considered here as animals and the parent plant itself. Within biotic agents, the most important are animals, specifically birds. Most bird-dispersed species present drupoid diaspores. Our results indicate that the selective pressures on dispersal syndromes originated from climate conditions that vary with altitude are not strong, hence resulting in the same dispersal spectrum among the forest types. Keywords: animal dispersal, biotic dispersal, bird dispersal, hierarchy of classification of dispersal syndromes. Biota Neotropica. 14(1): e20130003. MARTINSBiota Neotropica. 14(1): e20130003.abió tica e bió tica), três no nível seguinte (vento, pró pria planta parental e animais), três no nível intermediá rio (barocoria, autocoria e endozoocoria), duas no quarto nível (mamíferos e aves) e 12 síndromes no nível mais específico, relacionadas à morfologia dos diá sporos dispersos pelo vento, autocoria, mamíferos e aves. O espectro de dispersã o nos cinco níveis foi similar nas quatro formações florestais. De forma geral, a maior parte das espécies é dispersa por agentes bió ticos, aqui considerados animais e a pró pria planta parental. Dentre os agentes bió ticos, os mais importantes sã o os animais, especificamente as aves. A maioria das espécies dispersas pelas aves apresenta diá sporos drupó ides. Nossos resultados indicam que as pressõ es seletivas sobre as síndromes de dispersã o ocasionadas pelas condiçõ es climá ticas que variam com a altitude não sã o fortes. Assim, a ausência destas pressõ es ...

Phylogeny contributes more than site characteristics and traits to the spatial distribution pattern of tropical tree populations

“…This reinforces the finding that more specific dispersal syndromes are not necessarily correlated to dispersal agents (Jordano 1995, Howe 2016 and thus might show a wide variation in realized dispersal patterns at the local scale (Muller-Landau et al 2008). Additionally, our results outline the importance of evaluating the patterns generated by seed dispersal within dispersal syndromes belonging to hierarchical levels of similar variation in diaspore morphology, as proposed by Martins et al (2014).…”

“…We characterized the dispersal mechanism through the use of seed dispersal syndromes, as did other authors (Hubbell 1979, Condit et al 2000, Seidler and Plotkin 2006, Réjou-Méchain et al 2011. We classified the dispersal syndromes using the hierarchical levels proposed by Martins et al (2014) (details in Supplementary material Appendix 3).…”

“…that prevents the larger-scale spatial structure from being fully captured (Wiegand and Moloney 2014). We could only capture the spatial signature of seed dispersal syndromes belonging to the first hierarchical level of classification proposed by Martins et al (2014), i.e. biotic and abiotic dispersal.…”

A role for fruit structure in seed survival and germination of Swartzia langsdorffii Raddi beyond dispersal

“…Martins et al . () stated that S. langsdorffii diaspores have characteristics for dispersal by mammals and, as mentioned above, these diaspores are rich in secondary compounds (tannins and phenolic compounds) and saponins. Neither in the work of Vaz et al .…”

“…Considering these traits, Martins et al . () suggested that S. langsdorffii offspring are dispersed by mammals, since the bright colour and odour of the pericarp and aril may attract animals. However, Vaz et al .…”