Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Abstract

Aim To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser‐availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource‐availability hypothesis). Time period Tree‐inventory plots established between 1934 and 2019. Major taxa studied Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree‐inventory plots across terra‐firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance‐weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra‐firme forests (excluding podzols) compared to flooded forests. Main conclusions The disperser‐availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.

Floristic richness and diversity of Bintuni mangrove, Bird's Head Peninsula, West Papua, Indonesia

“…This situation could spread river flow to the riverbank, causing water inundation in some forests. Another thing was that vegetation diversity also appears in mangrove trunks which provided a place for epiphytes and climbers since the trunks have a rough surface that allows seeds or spores to be placed probably by zoochorous species or anemochorous process (López-Martínez et al 2013;Chen et al 2020;Pedraza et al 2021;Correa et al 2022;Wendt et al 2022). We accentuated that the species such as M. pendens and P. novoguineae (Christ) M.G.Price are native to New Guinea.…”

“…Moreover, the areas of Bintuni Mangroves also comprised riparian forests since there are many rivers. Hence, the hydrochory mechanism is imperative to affect seeds, spores, and fruits during seed dispersal (Polidoro et al 2010;Correa et al 2022). Thus, this can be the explanatory factor concerning the presence of species such as I. palembanica and P. dalbergioides as mangrove associates vegetation and the high number of species richness in the Bintuni mangrove.…”

“…The reproductive organs could come from another part of the terrestrial forest close to the shoreline; then, they reach the delta area to grow as vegetation establishments (Chen et al 2020;Correa et al 2022;Wendt et al 2022). The tidal mechanism affects the distribution of reproductive organs predominantly to the inland area since the high tide in the nature reserve and owing to the flat area leading to the rising water river surface.…”

How Does Changing Environment Influence Plant Seed Movements as Populations of Dispersal Vectors Decline?

“…Hydrochory (seed dispersal by water), which is common in low-lying areas that are frequently flooded, is one of the adaptations of plants in changing environments [ 87 , 88 ]. The current systematic review found that a substantial proportion of plant species use water for dispersal or seed transport, which has also evolved to adapt to changing environmental conditions (e.g., flood and drought).…”

Drivers of dispersal and diversification in bromeliads

“…A higher canopy can behave as a physical barrier for the wind-dispersed seeds present in capsular fruits and also may positively influence the diversity of vertebrate dispersers, (Walter et al, 2017), favoring the dispersal in berry-fruited species. On the other hand, open canopies can favor the wind-dispersed seeds (Correa et al, 2022).…”