Epiphyte associations and canopy soil volume: nutrient capital and factors influencing soil retention in the canopy

Abstract

Canopy soil (CS) volume reflect epiphyte community maturity, but little is known about the factors that retain CS or species succession within it. Humus fern species (e.g. Phlebodium areolatum) appear capable of retaining CS.• In ten Quercus spp. we sampled 987 epiphyte mats to examine the role of the common epiphyte species and crown traits determining CS volume, in order to infer successional stages and identify pioneer and late successional species. Branch traits (height, diameter and slope), CS volume and cover of the epiphyte species were determined for each mat. Nutrient content was determined in CS random samples of 12 epiphyte associations and sizes (one sample from each size quintile).• A total of 60% of the mats lack CS. Cover of P. areolatum was the main variable explaining CS volume, and this species was present in 46.8% of those with CS. Epiphyte composition was highly variable, but pioneer (species appearing in monospecific mats, without CS) and late successional species could be identified. Canopy soil nutrient content was similar among the associations of epiphytes. Magnesium, Ca and pH decreased with CS volume, while P and N increased.• Phlebodium areolatum is associated with high CS volumes and could act as a key species in its retention. Monospecific mats of pioneer species lack CS or have low volumes, while CS is much higher in mats with late successional species, but the mechanisms of CS formation and nutrient retention in response to interactions between epiphyte species remain to be tested.Plant Biology 22 (2020) 541-552

Diversity and interactions of the epiphyte community associated with ant‐gardens are not influenced by elevational and environmental gradients

“…Only the gradient of precipitation influenced the composition of AG epiphytes, but not their richness, with some species occurring in particular sites. For example, Codonanthe Competition or facilitation (nurse plants) interactions limit or promote, respectively, the establishment of epiphyte species in the canopy (Jian et al, 2013;Chaves & Rossatto, 2020;Victoriano-Romero et al, 2020). The network analyses showed that the most frequent true AG epiphytes in the sites were also the most central in the regional network, while the non-true AG epiphytes lack importance in the network, suggesting that they are opportunistic (Kaufmann & Maschwitz, 2006) or even parasitic (Davidson, 1988) species that take advantage of the nutrients of the ant-garden substrate (Blüthgen et al, 2001).…”

Accidental epiphytes: Ecological insights and evolutionary implications

“…Similarly, the decomposition of dead organic matter is influenced by temperature and moisture (Bradford et al, 2016; Prescott et al, 2000). Therefore, arboreal soil is most abundant in the inner crown, where humidity is relatively high and the physical structures of the tree support its accumulation (Köhler et al, 2007; ter Steege & Cornelissen, 1989; Veneklaas et al, 1990; Victoriano‐Romero et al, 2020). At a stand level, both substrate types are particularly abundant in tropical montane cloud forests and subtropical and temperate rain forests (Gotsch et al, 2016).…”

Tree Species and Epiphyte Taxa Determine the “Metabolomic niche” of Canopy Suspended Soils in a Species-Rich Lowland Tropical Rainforest

“…Suspended soils along tree trunks and branches retain nutrients and water essential for the development of epiphytic plants [26] that directly depend on these limited pools of available nutrients [27]. These plants are morphologically and physiologically adapted to facilitate the accumulation of leaf litter and water and to maximize atmospheric and invertebrate-mediated delivery of nutrients [15,28,29] in the physically harsh and variable environmental conditions that prevail within the canopy [30].…”

“…Epiphytes have evolved numerous remarkable adaptations to facilitate nutrient uptake. For example, certain members of the Bromeliaceae family form water and litter-storing phytotelmata and take up nutrients through leaf-absorbing trichomes [29,34,35], whilst Asplenium ferns intercept falling leaf litter, which is then stored as organic matter adjacent to the roots [27,36]. For both epiphytes, this accumulation of leaf litter leads to the formation of organic matter or epiphyte-associated soils that harbor characteristic levels of microbial diversity [37,38].…”