Bromeliad Selection by Two Salamander Species in a Harsh Environment

Abstract

Bromeliad phytotelmata are frequently used by several Neotropical amphibian taxa, possibly due to their high humidity, microclimatic stability, and role as a refuge from predators. Indeed, the ability of phytotelmata to buffer against adverse environmental conditions may be instrumental in allowing some amphibian species to survive during periods of environmental change or to colonize sub-optimal habitats. Association between bromeliad traits and salamanders has not been studied at a fine scale, despite the intimate association of many salamander species with bromeliads. Here, we identify microhabitat characteristics of epiphytic bromeliads used by two species of the Bolitoglossa morio group (B. morio and B. pacaya) in forest disturbed by volcanic activity in Guatemala. Specifically, we measured multiple variables for bromeliads (height and position in tree, phytotelma water temperature and pH, canopy cover, phytotelma size, leaf size, and tree diameter at breast height), as well as salamander size. We employed a DNA barcoding approach to identify salamanders. We found that B. morio and B. pacaya occurred in microsympatry in bromeliads and that phytotelmata size and temperature of bromeliad microhabitat were the most important factors associated with the presence of salamanders. Moreover, phytotelmata with higher pH contained larger salamanders, suggesting that larger salamanders or aggregated individuals might modify pH. These results show that bromeliad selection is nonrandom with respect to microhabitat characteristics, and provide insight into the relationship between salamanders and this unique arboreal environment.

Pool choice in a vertical landscape: Tadpole‐rearing site flexibility in phytotelm‐breeding frogs

“…The survival of young often hinges on the quality of the rearing environments created or chosen by their parents. Whether it is by building nests (birds: Brown & Brown, 1991;mice: Bult & Lynch, 1997, Zhao et al, 2016, digging burrows (rodents: Ebensperger et al, 2014;Svendsen, 1976), or depositing clutches/larvae (e.g., salamanders: Ruano-Fajardo et al, 2014, frogs: Pettitt et al, 2018, the ecology of rearing sites is fundamental in shaping offspring success. For animals with external fertilization, breeding site choice can be especially important, as optimal conditions for egg clutches may differ from the optimal environment for hatchlings and adults (fish: Ottesen & Bolla, 1998, Mikheev et al, 2001salamanders: Nussbaum, 1987, Sih & Moore, 1993frogs: Vági et al, 2019).…”

“…Despite the widespread use of phytotelmata (Lehtinen, 2021), and the nonrandom site selection shown by many frog parents, few studies go beyond quantifying basic pool dimensions and pool occupation to understand tadpole deposition decisions. Further, the bulk of phytotelm studies are focused only on bromeliads (Mageski et al, 2016;Pettitt et al, 2018;Ruano-Fajardo et al, 2014), while work exploring potential trade-offs associated between different phytotelmata (i.e., physical and chemical properties as well as food-and predatorrelated pressures), and how these change across a vertical gradient, has gone largely overlooked (but see Brown et al, 2008a).…”

“…It is known that pool chemistry can change drastically depending on substrate ("dead" or "live"; see Figure 1), height, and community composition (Pettitt et al, 2018;Ruano-Fajardo et al, 2014). Thus, better understanding the ecology of high arboreal pools and characterizing phytotelmata across the vertical gradient could help explain both the apparent success of D. tinctorius in a wide range of pools and why parents sometimes carry their offspring to such heights.…”

Pool choice in a vertical landscape: tadpole rearing site flexibility in phytotelm-breeding frogs

“…The survival of young often hinges on the quality of the rearing environments created or chosen by their parents. Whether it is by building nests (birds: (Brown and Brown 1991); mice: (Bult and Lynch 1997, Zhao et al 2016), digging burrows (rodents: (Svendsen 1976, Ebensperger et al 2014), or depositing clutches/larvae (e.g., salamanders: (Ruano-Fajardo et al 2014), frogs: (Pettitt et al 2018)), the ecology of rearing sites is fundamental in shaping offspring success. For animals with external fertilization, breeding-site choice can be especially important, as optimal conditions for egg clutches may differ from the optimal environment for hatchlings and adults (fish: (Ottesen and Bolla 1998, Mikheev et al 2001); salamanders: (Nussbaum 1987, Sih and Moore 1993); frogs: (Vági et al 2019)).…”

“…It is known that pool chemistry can change drastically depending on substrate ('dead' or 'live'; see Fig. 1), height, and community composition (Ruano-Fajardo et al 2014, Pettitt et al 2018 understanding the ecology of high arboreal pools and characterizing phytotelmata across the vertical gradient could help explain both the apparent success of D. tinctorius in a wide range of pools, and why parents sometimes carry their offspring such heights. Further, D. tinctorius tadpoles predate on other species of phytotelm-breeders, making it a key amphibian species for understanding the niche partitioning amongst communities of phytotelm breeders.…”