The persistence of ant-following birds in small amazonian forest fragments

Abstract

SUMMARY Uiòt-netcaptuneò <a£ a/uny ant-fallowing bi/idò weJie xf.onitoh.en. during xhe. isolation ofa centJial Amazonian faorest faagments ofa 1 ha [n = 5), 10 ha [n = 4) and 100 ka[n = 1).

Effects of forest heterogeneity on occurrence and abundance of the scale-backed antbird, Hylophylax poecilinotus (Aves: Thamnophilidae), in the Amazon forest

“…BIERREGAARD & LOVEJOY (1989) also showed that insectivorous birds, which follow swarms of army ants, disappeared from forest fragments soon after their isolation from continuous forest. It has been also verified that H. poecilinotus abundance decreased in the 1 ha fragments, and that this species increased in the post-isolation data of the 10 ha fragments (HARPER 1989).…”

Ecosystem decay of Amazonian forest fragments: implications for conservation

“…Once isolated, small (1-10 ha) fragments initially lose species at a remarkably high rate; for example, dung and carrion beetle assemblages were markedly altered only 2-6 years after fragment isolation (Klein 1989). Local extinctions of birds (Harper 1989, Stouffer and Bierregaard 1995b, Stratford and Stouffer 1999, primates (Lovejoy et al 1986, Schwartzkopf and Rylands 1989, Gilbert and Setz 2001, and butterflies (Brown and Hutchings 1997) have also occurred more rapidly in small (1-10 ha) than in large (100 ha) fragments.…”

“…Some species will cross small clearings but are inhibited by larger expanses of degraded land. Woodcreepers (Dendrocolaptidae) were induced by translocations to move between the BDFFP fragments and nearby areas (80-150 m) of mainland forest (Harper 1989), but have disappeared from slightly moreisolated areas such as Barro Colorado Island in Panama (Robinson 1999). Large predators like jaguars (Panthera onca) and pumas {Puma concolor) traverse pastures and regrowth in the BDFFP study area, but would likely avoid these areas if hunters were present or human density was higher (Rabinowitz 2000).…”

“…Large predators like jaguars (Panthera onca) and pumas {Puma concolor) traverse pastures and regrowth in the BDFFP study area, but would likely avoid these areas if hunters were present or human density was higher (Rabinowitz 2000). Some ant-following birds (Pithys albifrons, Gymnopithys rufigula, Dendrocincla merula) translocated into forest fragments where army ants are absent will cross clearings of 100-320 m to return to primary forest (Lovejoy et al 1986, Harper 1989), although clearings of only 100 m preclude their movements under normal circumstances (Bierregaard and Lovejoy 1989, Stouffer and Bierregaard 1995b, S.G. Laurance and Gomez 2005.…”

“…Predation on understory and litter arthropods has probably declined because of a collapse of insectivorous bird Bierregaard 1995b, Stratford and, bat (Kalko 1998, Sampaio 2000, and army ant (Harper 1989, Bierregaard et al 1992 assemblages. It seems plausible that these declines could be partly responsible for increased insect abundance near forest edges (Lovejoy et al 1986) and might even promote increased herbivory in fragments (Benitez-Malvido et al 1999).…”