Conversion of natural forests into monoculture rubber plantations reduces species richness and changes the composition of animal assemblages. It is necessary to identify conservation strategies that could improve biodiversity within monoculture rubber landscapes. 

Researchers form Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to determine the effects of forests, roads and mistletoes (a diverse group of parasitic plants that are found on rubber trees) on bird diversity in monoculture rubber plantations in Xishuangbanna.

The researchers compiled a comprehensive checklist of resident birds that occurred in the entire landscape (forest, villages, rubber and banana plantations) and compared it with a checklist of resident birds that occurred in rubber plantations to determine the life history traits that predicted occurrence probabilities of birds in rubber plantations. They then conducted 52 bird point counts (repeated four times) across a distance gradient from roads and primary forests within monoculture rubber to determine the effects of forest and roads on bird diversity and composition. They finally determined the effects of forest cover and rubber diameter at breast height (DBH) on mistletoe densities in rubber plantations, and made focal point observations to determine if frugivorous and nectarivorous birds feed on them.

They found that natural forests enhanced bird diversity within nearby monoculture rubber plantations. However, less than half of all the bird species in the study area were found in rubber even when forests where in close proximity. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover.

The results suggested that natural forests are irreplaceable for biodiversity conservation as more than half of the local bird species did not occupy monoculture rubber even when in close proximity to natural forests (<100 m). In order to maximize bird diversity in rubber-dominated landscapes, the researchers suggested that forest be preserved as much as possible, roads be constructed through plantations, and some large rubber trees with mistletoes be retained during crop rotations.

The study entitled “Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations” has been published in Scientific Reports.