Abundance and Diversity of Microfungi in Leaf Litter of a Lowland Rain Forest in Costa Rica

Mycologia ◽  
1994 ◽  
Vol 86 (2) ◽  
pp. 187 ◽  
Author(s):  
Gerald F. Bills ◽  
Jon D. Polishook
Keyword(s):  
Costa Rica ◽  
Leaf Litter ◽  
Rain Forest ◽  
Lowland Rain Forest ◽  
Abundance And Diversity

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

Roost availability and population size of Thyroptera tricolor, a leaf-roosting bat, in north-eastern Costa Rica

2004 ◽  
Vol 20 (3) ◽  
pp. 291-305 ◽  
Author(s):  
Maarten J. Vonhof ◽  
M. Brock Fenton
Keyword(s):  
Costa Rica ◽  
Population Size ◽  
Rain Forest ◽  
Size Range ◽  
Habitat Availability ◽  
Occupancy Rate ◽  
Lowland Rain Forest ◽  
Closed Population ◽  
North Eastern ◽  
Thyroptera Tricolor

Estimates of roosting habitat availability and population size using unbiased sampling regimes are completely lacking for any bat species. The use of conspicuous and accessible roosts in the developing, rolled leaves of Heliconia and Calathea plants by Thyroptera tricolor (Spix's disc-winged bat) provided an ideal opportunity to address this need. To assess roost availability and population size, the number of occupied and unoccupied leaves and bats in known areas in an area of lowland rain forest in north-eastern Costa Rica were quantified in 1998–99. A high density of leaves was available on any given day (mean: 43 leaves ha−1), but the density of roost leaves was low (mean: 2.5 leaves ha−1), corresponding with a low occupancy rate of 5.7 or 12% based on different methods of estimation. Developing leaves were available for 8–16 h in the preferred size range of leaves used by T. tricolor, and a maximum of 28–60 h, depending on the plant species. Using closed-population mark–recapture models, the 5.69-ha study area supported 261 individuals over a 4-mo period in 1998, corresponding to a density of 43 bats ha−1. These results have important implications for the results of studies on bat community structure and rarity, and for the behaviour and ecology of T. tricolor.

Habitat-dependent fruiting behaviour of an understorey tree,Miconia centrodesma, and tropical treefall gaps as keystone habitats for frugivores in Costa Rica

1990 ◽  
Vol 6 (4) ◽  
pp. 409-420 ◽  
Author(s):  
Douglas J. Levey
Keyword(s):  
Costa Rica ◽  
Reproductive Success ◽  
Rain Forest ◽  
Fruit Production ◽  
Costa Rican ◽  
Forest Trees ◽  
Lowland Rain Forest ◽  
Treefall Gaps ◽  
Forest Sites ◽  
Understorey Plants

ABSTRACTFruit production by an understorey tree,Miconia centrodesma, was monitored in treefall gaps and under intact canopy in a Costa Rican lowland rain forest. Trees in gaps displayed much less seasonality in fruit production than trees of intact forest sites. For example, ripe fruits were common on gap trees for a six month period (January-June) when few or no trees under intact canopy were in fruit. The frequent and aseasonal fruiting of gap trees demonstrates that they are not constrained by phenological cueing mechanisms; the influence of such cues is overridden by habitat. Trees in gaps also produced larger crops, had more extended fruiting episodes, and fruited more frequently than shaded conspecifics. This level of intraspecific variation in fruiting behaviour suggests that treefall gaps play an important role in determining the reproductive success ofM. centrodesma. A substantial proportion of an individual's lifetime seed output may be produced during the brief period it occupies a gap. In addition, the large and continuous supply of fruits produced in gaps byM. centrodesmaand other understorey plants, may mean that gaps function as ‘keystone habitats’ by providing resident frugivores with fruit during periods of general fruit scarcity.

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