The influence of agricultural system, stand structural complexity and landscape context on foraging birds in oil palm landscapes

Abstract

Functional diversity, an important element of avian biodiversity, can be examined by quantifying foraging guild composition. Understanding the ecological processes that underpin functional diversity of birds in oil palm Elaeis guineensis landscapes is important because different foraging guilds are likely to be influenced in different ways by land use practices. We surveyed birds at 55 sites within oil palm landscapes and at 20 sites within logged peat swamp forest, recording 208 species belonging to 19 foraging guilds. Oil palm landscapes supported a lower abundance of insectivorous, granivorous and omnivorous birds than did logged peat swamp forest despite the latter being severely degraded due to intensive timber extraction. However, abundances of other groups of foraging birds, such as raptors and wetland taxa, were higher in oil palm landscapes than logged peat swamp forest. Frugivorous species were more abundant in smallholdings than plantation estates, probably because of the presence of native trees. Foraging guild diversity was explained by stand‐level attributes such as stand age, vegetation cover, epiphyte persistence and canopy cover. However, each foraging guild exhibited unique responses to different oil palm management regimes and stand‐level attributes. Only arboreal omnivores and terrestrial frugivores were affected by the proximity of nearby natural forest. This diversity of responses implies that the occurrence of particular avian foraging guilds may not be a suitable ecological indicator of best‐practice palm oil production. Our study also suggests that multiple conservation measures will be needed in oil palm landscapes irrespective of management regimes, including: (1) the maintenance of ground layer vegetation cover; (2) the pruning of oil palm canopy to permit light penetration to the ground layer; (3) re‐vegetation of parts of oil palm landscapes with native trees; and (4) retention of natural and/or secondary forest patches within the boundaries of plantations.

Barriers to dispersal of rain forest butterflies in tropical agricultural landscapes

“…Forest connectivity may also be improved by making non‐forest areas more hospitable (Azhar et al . ) and by improving quality of remaining forest areas (Mair et al . ), thereby helping to reduce biodiversity losses in tropical agricultural landscapes.…”

Effects of water quality in oil palm production landscapes on tropical waterbirds in Peninsular Malaysia

“…Bird species diversity is generally lower in oil palm plantations compared with forested areas (Aratrakorn et al 2006;Koh 2008;Edwards et al 2010;Azhar et al 2013Azhar et al , 2014. However, there is little specific information about waterbirds and their habitats within oil palm plantations.…”

Efecto de la estructura del cultivo de palma de aceite Elaeis guineensis (Arecaceae) sobre la diversidad de aves en un paisaje de la Orinoquía colombiana

“…Esta tendencia se ha encontrado en estudios previos y se ha considerado que este conjunto de especies actúan sobre el control de insectos que representan riesgos para el cultivo (Enríquez Bernal, 2006;Achondo et al, 2011;Azhar et al, 2013). Sin embargo, también se ha encontrado que las aves generalistas y frugívoras son abundantes.…”

“…Sin embargo, también se ha encontrado que las aves generalistas y frugívoras son abundantes. Azhar et al (2013) encontraron que las aves frugívoras fueron abundantes en palmas pequeñas, posiblemente porque los lotes donde fueron registradas tuvieron mayor proximidad con árboles nativos, y que la mayoría de los grupos tróficos fueron dominados por pocas especies. Las aves nectarívoras exhibieron mayor sensibilidad al establecimiento de la plantación si se tiene en cuenta la escasa abundancia proporcional de los individuos (Amazilia versicolor).…”

“…Las aves nectarívoras exhibieron mayor sensibilidad al establecimiento de la plantación si se tiene en cuenta la escasa abundancia proporcional de los individuos (Amazilia versicolor). Estudios previos no relacionan la presencia de este grupo trófico con el cultivo de palma, lo que concuerda con la reducción la diversidad funcional de las aves en paisajes dominados por cultivos de palma de aceite (Azhar et al, 2013, Prescot et al, 2016.…”