Fig 1.
Location of the primary-secondary forest transects at the Biological Dynamics of Forest Fragments Project, Central Amazon, Brazil.
(a) Transect location within the BDFFP is presented in the inserts, where primary forest is denoted in white and secondary forest is presented in green. (b) Location of the BDFFP in Brazil. Photographs show the plastic dividers used to ensure acoustic recordings from the understory (c) and canopy samples (d) were independent.
Fig 2.
Visual representation of the five models proposed by Ewers & Didham [19] to delineate species’ theoretical responses to edge effects.
(a) For the null, linear, and power models it is not possible to calculate extent or magnitude as there is either no response present or the response exceeds the sampling area; (b) in the sigmoid model, species exhibit a negative response to edge effects and asymptotes are reached in each habitat; and (c) in the unimodal model, species demonstrate a preference for edge habitat. Note, we have illustrated here a hypothetical preference for secondary forest using the linear and sigmoid model and a preference for primary forest using the power model. However, each of these models can be used to demonstrate a preference for either habitat.
Table 1.
Total number of bat passes per species/sonotype in both the understory and canopy of secondary forest, forest edge, and primary forest.
Fig 3.
Edge effect model fit for forest specialists in the understory.
Log forest specialist activity (bat passes) per 50 m sample point averaged across all transects with corresponding lines of best fit. Activity increases from the edge in the secondary forest and decreases from the edge in the primary forest. Dark blue dash–power model, light blue–linear model. Standard error provided for the linear model. Model parameters listed in S2 Table.
Table 2.
Comparison of model fit using Ewers and Didham’s (2006) edge effect models.
Table 3.
Summary of the best-fit generalized linear mixed effect models for each bat guild and species/sonotype.
Fig 4.
Vertical stratification of twelve Amazonian bat species.
Comparison of total bat activity (bat passes) per species/sonotype recorded in the understory and canopy at the Biological Dynamics of Forest Fragments Project. Significance values * < 0.05, *** < 0.001.
Fig 5.
Schematic of bidirectional response to edge effects.
A theoretical example of how activity/abundance may exhibit a bidirectional response to edge effects. The complementation zone would be the area between the first asymptotes from the edge in each habitat. The full extent of edge effects is observed at the second asymptotes from the edge in each habitat whereby activity stabilises.