Birds of the Juruá River: extensive várzea forest as a barrier to terra firme birds

Revealing floristic variation and map uncertainties for different plant groups in western Amazonia

“…This might be expected, because the Juruá river channel is narrow, extensively meandering and with slow streamflow compared with rivers that have more often been cited as barriers (Wallace, 1852;Ayres & Clutton-Brock, 1992;Aleixo, 2004;Ribas et al, 2012). However, the Juruá has an extensive floodplain, and recent analyses of taxonomically updated data have revealed more pronounced differences in primate species composition (Fordham et al, 2020) and plumage colour of some understorey birds (Del-Rio et al, 2021) from the non-inundated areas across the river. To what degree these observations are related to habitat variation vs the presence of the river and its floodplain remains an open question.…”

Full Issue

“…However, the recent version of the CBRO checklist (Pacheco et al 2021) that birds east of the Juruá are caelestipileata. Del-Rio et al (2021) sampled a restricted region (Carauari) of the middle Juruá River c.550 km distant from locations where specimens in Acre were collected (Fig. 1).…”

“…again argued for excluding exquisita, ignoring the specimens from Acre (Table1; Figs.3A and 4), and also noted thatDel-Rio et al (2021) had confirmed…”

On the sympatric occurrence of two subspecies of Blue-crowned Manakin, Lepidothrix coronata exquisita and L. c. caelestipileata, in south-west Amazonia

“…However, the recent version of the CBRO checklist (Pacheco et al 2021) again argued for excluding exquisita, ignoring the specimens from Acre (Table 1; Figs. 3A and 4), and also noted that Del-Rio et al (2021) had confirmed that birds east of the Juruá are caelestipileata. Del-Rio et al (2021) sampled a restricted region (Carauari) of the middle Juruá River c.550 km distant from locations where specimens in Acre were collected (Fig.…”