Bird Responses to Lowland Rainforest Conversion in Sumatran Smallholder Landscapes, Indonesia

Abstract

Rapid land-use change in the tropics causes dramatic losses in biodiversity and associated functions. In Sumatra, Indonesia, lowland rainforest has mainly been transformed by smallholders into oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) monocultures, interspersed with jungle rubber (rubber agroforests) and a few forest remnants. In two regions of the Jambi province, we conducted point counts in 32 plots of four different land-use types (lowland rainforest, jungle rubber, rubber plantation and oil palm plantation) as well as in 16 nearby homegardens, representing a small-scale, traditional agricultural system. We analysed total bird abundance and bird abundance in feeding guilds, as well as species richness per point count visit, per plot, and per land-use system, to unveil the conservation importance and functional responses of birds in the different land-use types. In total, we identified 71 species from 24 families. Across the different land-use types, abundance did not significantly differ, but both species richness per visit and per plot were reduced in plantations. Feeding guild abundances between land-use types were variable, but homegardens were dominated by omnivores and granivores, and frugivorous birds were absent from monoculture rubber and oil palm. Jungle rubber played an important role in harbouring forest bird species and frugivores. Homegardens turned out to be of minor importance for conserving birds due to their low sizes, although collectively, they are used by many bird species. Changes in functional composition with land-use conversion may affect important ecosystem functions such as biological pest control, pollination, and seed dispersal. In conclusion, maintaining forest cover, including degraded forest and jungle rubber, is of utmost importance to the conservation of functional and taxonomic bird diversity.

Switching from monoculture to polyculture farming benefits birds in oil palm production landscapes: Evidence from mist netting data

“…As a result, it probably provides greater resources (e.g., food plants, prey availability, and shelter) for birds and other fauna than monoculture plantations (Jones & Sieving, ; Malézieux et al., ). In Sumatra, home gardens (which resemble the polyculture system (De Clerck & Negreros‐Castillo, )) were found to be populated by omnivores and granivores, and frugivorous birds that were absent from monoculture oil palm (Prabowo et al., ). Intercropping oil palm with other edible plants or crops can also improve food security and cushion farmers from commodity price fluctuation (Koczberski & Curry, ; Koh, Levang, & Ghazoul, ).…”

“…In contrast, polyculture farming increases floristic diversity and stand structural complexity. As a result, it probably provides greater re- found to be populated by omnivores and granivores, and frugivorous birds that were absent from monoculture oil palm (Prabowo et al, 2016). Intercropping oil palm with other edible plants or crops can also improve food security and cushion farmers from commodity price fluctuation (Koczberski & Curry, 2005;Koh, Levang, & Ghazoul, 2009).…”

Autonomous sound recording outperforms human observation for sampling birds: a systematic map and user guide

“…The avoidance effect could depend on the bird community and sampling habitat: as Prabowo et al. () illustrated based on detection distances (Fig. S1), birds in disturbed systems tend to be attracted to human presence, while birds in natural systems tend to avoid it.…”

“…Furthermore, birds can also be unaffected by human observers, as determined by a study locating birds with a microphone array when human observers are present or absent, even though the authors were careful not to generalize their results to other bird communities (Campbell and Francis 2012). The avoidance effect could depend on the bird community and sampling habitat: as Prabowo et al (2016) illustrated based on detection distances ( Fig. S1), birds in disturbed systems tend to be attracted to human presence, while birds in natural systems tend to avoid it.…”

Oil palm and biodiversity: a situation analysis by the IUCN Oil Palm Task Force

“…Rubber grown as a monoculture has a similar negative impact on bird species richness as oil palm in both Indonesia and Thailand (252,253), although for some other species groups rubber might be richer than oil palm (85). Given that small-scale agriculture is such a large driver of deforestation as well it is important to determine whether this drives lower biodiversity losses as a mix of trees and crops (agroforestry) than as a monoculture.…”