How Many Ferns Are There in One Hectare of Tropical Rain Forest?

Abstract

The number of species of ferns in the Neotropics can be estimated to be about 3500. Pteridophytes have been treated in several recent neotropical floras (e.g., Lellinger, 1989; Proctor, 1985; Tryon and Stolze, 1989a, 1989b, 1991, 1992, 1993, 1994) and the fern flora has been documented for a number of local areas, for example La Selva (McDade et al., 1994), Barro Colorado (Croat, 1978), Rio Palenque (Dodson and Gentry, 1978), or Rio Abiseo N.P. (Young and Le6n, 1991), but very few attempts have been made to make total pteridophyte species counts on a small-scale or to include quantitative measurements. In a total species count in 0.01 ha of rain forest in Costa Rica, Whitmore et al. (1985) found 21 species and 204 individuals of ferns, including free-standing plants (9 species, 107 individuals), climbers (3, 10) and epiphytes (9, 87). In Peru, Young and Le6n (1989) sampled approximately two hectares (10 m x 2 km) and found 61 species of ferns and fern allies on the ground; Tuomisto and Ruokolainen (1994) collected ferns up to 2 m above the ground in two transect plots of 0.35 ha and found 35 and 36 species, in each plot respectively, but there was no attempt to include all of the epiphytic species. The present investigation is to our knowledge the first documentation of the total number of species of ferns and fern allies in a one hectare plot in a tropical lowland rain forest.