The expansion of oil palm cultivation is recognised as a major cause of tropical biodiversity loss. In contrast to large-scale plantations, oil palm smallholdings being more heterogeneous may support greater biodiversity. This study examined the effects of local and landscape level variables on the composition of nocturnal bird species in Malaysian oil palm smallholdings. Using visual and aural point sampling, we made 1408 encounters with nine owl and two nightjar species. The Biota-Environment-Stepwise matching analyses (BEST) indicated four predictor variables (three local variables; number of crop species, widths of roads and trenches, and one landscape variable; distance to the nearest main road) significantly influenced the community assemblages of nocturnal bird species in the smallholdings. Generalized Linear Models (GLMs) further indicated seven predictor variables (numbers of palms and houses, widths of roads and trenches, distances to the nearest forest and house, as well as palm height) significantly influenced the abundances of certain nocturnal species. These findings not only improve our understanding on habitat preference of nocturnal birds in the Sunda region but also support the argument that habitat complexity in cultivated areas may aid in biodiversity conservation, at least for nocturnal birds.

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Herbicide overuse decimates understory vegetation, including those beneficial plants which may lead to a reduction of some production‐related ecosystem services such as nutrient cycling, water regulation, natural pest control, and pollination. Such conventional weed management practices need to be replaced with environmentally friendly methods such as ecological grazing to make palm oil supply chain environmentally sustainable. Contrary to chemical weeding, livestock integration is believed to be a useful tool to control weeds without negative impact to human health and the environment. However, little is known about the influence of different livestock grazing practices on oil palm understory vegetation. Thus, the present study investigates the effects of weed management practices (i.e., rotational grazing, free‐ranged grazing, and conventional weeding) on understory vegetation species richness, composition assemblages, and structural complexity. Based on plant surveys that were conducted on 360 sampling points, 120 understory vegetation species consisting of grasses, sedges, ferns, and legume covers were recorded. We found understory vegetation composition assemblages were different between treatments. Results revealed that the number of understory vegetation species, coverage, and height were significantly higher in rotational grazing compared with other practices. Given the major contribution of vegetation composition assemblages and structure on palm oil productions and biodiversity, oil palm growers should adopt rotational livestock grazing as a part of an integrated pest management strategy to control understory vegetation.

A high demand for palm oil has led to the continued expansion of oil palm agriculture at the expense of tropical forests and forest biotic communities in many developing countries. The response of wildlife to oil palm establishment has been shown to vary according to taxa, and many forest species may not be able to adapt to the altered landscape. Many nocturnal bird species have been recorded in oil palm agriculture. Whether such forest species can also thrive in such a landscape is not known, and their responses to habitat complexity are poorly understood. We conducted point surveys of nocturnal birds (Tytonidae, Strigiformes and Caprimulgiformes over 80 points spaced at least 800 m apart and revisited five times) in oil palm smallholdings at Tanjung Karang, Kuala Selangor. Environmental factors measured at each point included: average height of oil palm stands, palm density, crop richness, and distances to the nearest forest, river and road. We recorded a total of 577 individuals of seven species. Palm density and distance to river were found to positively influence nocturnal bird species richness, whereas distance to the nearest forest was found to negatively influence avian species richness. In the case of abundance, number of oil palms, crop richness, and distance to the nearest river were found to influence nocturnal bird abundance positively in the smallholdings; however, distance to the nearest forest was found to influence bird abundance negatively. These findings suggest that maintaining key vegetation structure while reducing manmade structures such as roads may benefit nocturnal bird species in the smallholdings particularly those of open and semi-open habitats. However, the number of forest-associated species remained low in the smallholdings, which may only serve as suboptimal habitat for these birds. This implies that forest-associated species may not be able to persist in such landscapes.