Species-specific associations between overstory and understory tree species in a semideciduous tropical forest

Abstract

We investigated the occurrence of associations between overstory and understory tree species in a semideciduous tropical forest. We identified and measured all trees of nine canopy species with diameter at breast height ≥4.8 cm in a 10.24 ha plot and recorded all individuals beneath their canopies ("understory individuals") within the same diameter class. The total density of understory individuals did not significantly differ under different overstory species. One overstory species (Ceiba speciosa) showed higher understory species richness compared with five other species. There was a strong positive association between three overstory species (Esenbeckia leiocarpa, Savia dictyocarpa, and C. speciosa) and the density of seven understory species (Balfourodendron riedelianum, Chrysophyllum gonocarpum, E. leiocarpa, Holocalyx balansae, Machaerium stipitatum, Rhaminidium elaeocarpum, and S. dictyocarpa). These results probably reflect the outcome of a complex set of interactions including facilitation and competition, and further studies are necessary to better understand the magnitude and type of the effects of individual overstory species on understory species. The occurrence of species-specific associations shown here reinforces the importance of non--random processes in structuring plant communities and suggest that the influence of overstory species on understory species in high-diversity forests may be more significant than previously thought.

Alpine cushion plants have species–specific effects on microhabitat and community structure in the tropical Andes

“…In addition, tree species in a semi‐deciduous forest of Brazil also appear to have species‐specific interactions with understorey species (Souza et al. ), as do shrubs in semi‐arid environments in Spain (Gomez‐Aparicio et al. ).…”

Floristics and Structure of Arboreal Components in a Restored Atlantic Forest Area

“…Phytosociological analyzes allows to assess environmental impact for the sustainable use, conservation and restoration of the ecosystems (Durigan, 2009). The successional stages and interventions to recover a forest closer to a stage of balance are evaluated by analyzes of the oristics and structure of the arboreal component and in this study a reference area for comparison is used a lot, and whether the area is really restored or close to a natural area (Souza et al, 2015;Balestrin et al, 2019;Gardon et al, 2020).…”

Facilitative effects of tree species on natural regeneration in an endangered biodiversity hotspot

“…In a forest ecosystem, the upper stratum of the plant community forms a cover, which changes the structure and diversity of the vegetation of the lower stratum (e.g., Foré et al 1997;Souza et al 2015). The magnitude of this effect is dependent on the species of the upper stratum, as well as the plant-plant interactions (Padilla and Pugnaire 2006;Souza et al 2015).…”

“…In a forest ecosystem, the upper stratum of the plant community forms a cover, which changes the structure and diversity of the vegetation of the lower stratum (e.g., Foré et al 1997;Souza et al 2015). The magnitude of this effect is dependent on the species of the upper stratum, as well as the plant-plant interactions (Padilla and Pugnaire 2006;Souza et al 2015). Plant species can be responsible for limiting the abundance, survival and spatial distribution of other species under their canopies (Gandolfi 2003), thereby functioning as ecological filters (Gandolfi 2003;Gandolfi et al 2007) or enhance the abundance and performances of plant species acting as nurse plants (e.g., Nobel 1980;Franco and Nobel 1989;Sánchez-Velásquez et al 2004;Duarte et al 2006;Padilla and Pugnaire 2006).…”

“…In habitats with extreme environmental conditions, such as deserts, prairies, mountain tops and sandy coastal plains, studies have identified the importance of some species for the recruitment and development of saplings in the understory (e.g., Castro et al 2002;Sánchez-Velásquez et al 2004;Duarte et al 2006;Alday et al 2014;Molina-Montenegro et al 2016). However, in tropical forests, where environmental conditions are more favorable, there is a lack of studies that document the existence of facilitation among species (but see, Vieira et al 1994;Vieira and Galdolfi 2006;Biaou et al 2011;Liu et al 2013;Scowcroft and Yeh 2013;Avendaño-Yáñez et al 2014;Souza et al 2015;Melo et al 2015). More studies in tropical forests are therefore needed, especially in highly fragmented forests such as the Brazilian Atlantic Forest, which in spite of being a major global biodiversity hotspot, currently retains just over 11% of its original vegetation in small fragments (\50 ha) (Myers et al 2000;Ribeiro et al 2009).…”