Tree Species Composition, Breeding Systems, and Pollination and Dispersal Syndromes in Three Forest Successional Stages in a Tropical Dry Forest in Mesoamerica

Abstract

Tropical dry forests (TDF) in Mesoamerica are highly endangered by the expansion of human activities (e.g., agriculture and cattle ranching). In contrast, TDF in Costa Rica have experienced outstanding restoration due to changes in economic and conservation policies. Currently TDF landscapes in Costa Rica are a mosaic of different successional stages. Tree breeding systems and pollination and dispersal syndromes are key elements for understanding restoration processes in TDFs. In this study we describe and compare tree species composition and diversity in three TDF successional stages (early, intermediate and late) in Guanacaste, Costa Rica. We describe for the first time tree species breeding systems and pollination and dispersal syndromes for the largest and most significant TDF remnant in Mesoamerica. We set up nine plots, three per successional stage, and we measured and identified 1,072 trees from 96 species. Species richness and diversity indices were higher for the intermediate stage. Monoecy was the most common breeding system, as in other tropical life zones. Insects were the dominant pollinators, facilitated by the trees' small inflorescences. Wind was found to be not only the next most influential pollinator, mainly in open and disturbed early forests, but also it was also a good seed dispersal agent. As TDF age increases so does the relevancy of birds and mammals as dispersers; the late stage therefore has more tree species with adaptations to these dispersers.

Defaunation as a trigger for the additional loss of plant species in fragmented landscapes: considerations on the state of Espírito Santo, southeastern Brazil

“…Bats and plants have a very strong interaction and when bats consume fruits, nectar or pollen, they provide seed dispersal and pollination in exchange for the nutrients the plants provide. Thus, the association between many plants and bats is often exclusive, and some plant species have clearly coevolved with bats for seed dispersal (chiropterocory) and pollination (chiropterophily, Hilje et al 2015).…”

“…Several plant families are dispersed by medium and large mammals and include the important families Anacardiaceae, Arecaceae, Annonaceae, Celastraceae, Chrysobalanaceae, E u p h o r b i a c e a e , F a b a c e a e , L a u r a c e a e , Malphigiaceae, Melastomataceae, Moraceae, Myrtaceae, Rubiaceae and Sapotaceae, along with many others in the Atlantic Forest (Hilje et al 2015;Bueno et al 2013). Thus, the loss of larger mammals can completely change the dynamics of dispersal for many species in these (and other) families, thereby potentially altering community composition and genetic structure of the populations.…”

Resilience of seed production to a severe El Niño‐induced drought across functional groups and dispersal types

“…Seed sampling was carried out monthly beginning in October of 2013 until December of 2017. All seeds and fruits in the traps were counted, identified to species, and assigned to a functional group (drought‐deciduous, evergreen or liana) based on Powers and Tiffin () and dispersal type (vertebrate, gravity/autochory and wind) based on Hilje, Calvo‐Alvarado, Jiménez‐Rodríguez, and Sánchez‐Azofeifa (). See Supporting Inforamtion Table S1 for the list of species, their functional groups, dispersal types, and seed mass (from Vargas, Werden, & Powers, ).…”

Edaphic factors, successional status and functional traits drive habitat associations of trees in naturally regenerating tropical dry forests

“…Powers, unpublished), wood vessel diameter (mm) and xylem vessel density (# vessels/cm 3 ; Werden, Waring, et al, 2018). Finally, we considered species-level dispersal syndrome (animal, wind or gravity, both; Powers et al, 2009;Hilje, Calvo-Alvarado, Jiménez-Rodríguez, & Sánchez-Azofeifa, 2015).…”