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

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

Data from: Bird responses to lowland rainforest conversion in Sumatran smallholder landscapes, Indonesia

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

Rarefied species richness after three 20 minute visits, split up by land-use type for both regions combined in the province of Jambi, Sumatra.

<p>Grey dots represent plots, red dots represent mean values per land-use type, error bars represent the mean standard error, asterisks denote statistical significance in post-hoc multiple comparisons with forest.</p

Homegarden plants

Plant species found during he homegarden survey. Abundances are approximate above 30 individuals

Bird survey info

Point count visit info with date, time, cloud cove

Total bird richness after three 20 minute visits in each land-use type and IUCN Red List threat status for two regions in the province of Jambi, Sumatra.

<p>For some unidentified birds, the threat status was not available (NA).</p

Bird data homegardens

Birds detected during 3-4 point count visits inside plots situated in homegardens of Jambi, Sumatra. The stratum and horizontal distance were not recorded in homegardens. The used plants were only recorded in homegardens. Plot code letters represent the landscape (B: Bukit 12, H: Harapan Rainforest), the land-use (F: forest, J: jungle rubber, R: rubber, O: oil palm, G: homeGarden), and the replicate

Non-metric Multidimensional Scaling of bird communities in different land-use types of Jambi, Sumatra.

<p>Graph based on abundance data from both regions.</p

Bird abundance and species richness per 20 minute visit, split up by land-use type for two regions in the province of Jambi, Sumatra.

<p>Black dots represent visits, red dots represent mean values per land-use type, error bars represent the mean standard error, asterisks denote statistical significance in post-hoc multiple comparisons with forest.</p