Influence of Selective Logging on Bird Species Diversity in a Guianan Rain Forest

Abstract

The composition and structure of the bird community were investigated in French Guiana (northeastern Amazonia) 1 year and 10 years after selective logging and compared with bird community composition and structure in undisturbed primary forest. A point‐count method was used in which 937 0.25‐ha sample quadrats were censused for 20 minutes each. Whereas logging removed little more than 3 trees/ha, 38% of the forest undergrowth was destroyed and a proportion of the canopy was opened or damaged. An overall 27–33% decrease of species richness, frequency, and abundance occurred after logging, with a less marked decline of diversity and evenness indices, a substantial increase in the proportion of dominant species, and a 45% difference in species composition, weighed by frequency, between logged and undisturbed forest communities. Forty‐two percent of the species from the primary forest decreased sharply or disappeared after logging and only 34% increased or remained unchanged. Microhabitat selection was the main correlate of sensitivity to disturbance. Most affected by logging were species associated with the understory of tall mature stands especially terrestrial species, members of mixed flocks, and solitary sallying insectivores, all of which decreased by 70% to over 90%. Most birds associated with canopy, small gaps, and vine tangles declined by only 10–30%. Small frugivores and species associated with clearings or edges increased. Among other factors, physiological intolerance of understory species to open forest microclimatic conditions (light, heat, or water stress) might influence their avoidance of logged areas. Timber harvesting generated a high level of disturbance, which depressed the bird diversity. After over 10 years of regeneration, the dense regrowth produced a uniform habitat type that still had not recovered the high species richness exhibited by the primary forest under an intermediate level of disturbance.

Does mixed-species flocking influence how birds respond to a gradient of land-use intensity?

“…The idea that mixed-species flocking species may be especially vulnerable was first raised by two classic studies of birds' responses to human disturbance [17,18] and was confirmed by Van Houtan et al [21]. All three of these studies were in Amazonia, with a unique system in which flocks defend interspecific territories [53].…”

“…Early reports on mixed-species flocks suggested that flocking species were particularly vulnerable to anthropogenic disturbance [17,18], and a number of studies have now investigated how flocks respond to fragmentation [19 -24] and to different land uses or successional stages [25 -30], with the near-universal finding of fewer and smaller flocks in more disturbed conditions. But the larger question of how and why the flocking phenomenon might influence how birds respond to land-use intensity is still unclear.…”

Effects of reduced-impact logging on medium and large-bodied forest vertebrates in eastern Amazonia

“…is relatively intolerant to selective logging (Thiollay 1992, 1997, Mason 1996. However, the response of golden-handed tamarin was unexpected, given that this specie is a generalist insectivore-frugivore (Pack et al 1999), and are widely found in secondary forest (Rylands & Keuroghlian 1988).…”

“…The first feature is the presence of relatively large areas without any history of RIL disturbance immediately adjacent to areas with RIL activities. One of the guidelines of RIL planning is the choice of areas with gentle topography and high concentrations of tree species with high commercial value (Thiollay 1992, Putz et al 2001). This fact allows for the persistence of ''islands'' of unlogged areas surrounded by logged ones.…”

Birds of a high-altitude cloud forest in Alta Verapaz, Guatemala

“…In other tropical regions, little similarity was found between commercially exploited forest and pristine forest (Newmark 1991, Thiollay 1992, Mason 1996. In Caquipec, the high degree of similarity between the bird communities of undisturbed and disturbed forest indicates that the subsistence use of forest resources by Q'eqchi' communities may have low impact on the overall species composition.…”