Nitrogen fluxes from treefrogs to tank epiphytic bromeliads: an isotopic and physiological approach

Abstract

Diverse invertebrate and vertebrate species live in association with plants of the large Neotropical family Bromeliaceae. Although previous studies have assumed that debris of associated organisms improves plant nutrition, so far little evidence supports this assumption. In this study we used isotopic ((15)N) and physiological methods to investigate if the treefrog Scinax hayii, which uses the tank epiphytic bromeliad Vriesea bituminosa as a diurnal shelter, contributes to host plant nutrition. In the field, bromeliads with frogs had higher stable N isotopic composition (delta(15)N) values than those without frogs. Similar results were obtained from a controlled greenhouse experiment. Linear mixing models showed that frog feces and dead termites used to simulate insects that eventually fall inside the bromeliad tank contributed, respectively, 27.7% (+ or - 0.07 SE) and 49.6% (+ or - 0.50 SE) of the total N of V. bituminosa. Net photosynthetic rate was higher in plants that received feces and termites than in controls; however, this effect was only detected in the rainy, but not in the dry season. These results demonstrate for the first time that vertebrates contribute to bromeliad nutrition, and that this benefit is seasonally restricted. Since amphibian-bromeliad associations occur in diverse habitats in South and Central America, this mechanism for deriving nutrients may be important in bromeliad systems throughout the Neotropics.

Adaptive radiation, correlated and contingent evolution, and net species diversification in Bromeliaceae

“…Fertile, humid tropical montane habitats select for the epiphytic habit, by favoring heavy rains and low evaporation rates at mid elevations (Gentry and Dodson, 1987;Grytnes and Beaman, 2006;Acharya et al, 2011) and a rich nutrient rain derived from leachate and shed parts from host trees, and possibly from animals or droppings derived ultimately from fertile soils (Janzen, 1974a(Janzen, ,b, 1977Benzing, 2000;Gentry and Emmons, 1987;Romero et al, 2006Romero et al, , 2010Benner and Vitousek, 2007). 2.…”

CAM Photosynthesis in Bromeliads and Agaves: What Can We Learn from These Plants?

“…The rosette conformation provides different compartments with distinct ecological conditions, serving as favorable habitats for a wide variety of organisms that, besides shelter, also need a supply of water to conclude their life cycles [104]. In addition, the organisms living in the tank may provide important nutrients to the plant [101,105].…”

“…Epiphytes notably enrich the tropical forest ecosystems by providing new niches for a great number of organisms [100,101] but are subjected to several environmental limitations. For example, nutrients and water are only available sporadically or seasonally through rainfall [102].…”

Jumping into a trap: high prevalence of chytrid fungus in the preferred microhabitats of a bromeliad-specialist frog

“…Amphibians have differing degrees of association with bromeliads (e.g. Jared et al 2005, Romero et al 2010. Peixoto (1995) functionally split anurans that use bromeliads into bromelicolous, when using bromeliads sporadically as shelter, and bromeligenous/bromeligens, when they complete their entire life cycle within bromeliads (e.g.…”