DOI: 10.5285/189164db-fe83-4b3f-b572-2fe99faba2d1
title: Socioecological data from smallholder oil palm plantations in Perak, Peninsular Malaysia, 2021-2022

description: This dataset includes results from biodiversity, social and environmental surveys of 49 oil palm smallholders and farms in Perak, Malaysia. Biodiversity data includes sticky trap data on flying invertebrate abundance (identified to higher-level order), transect data on assassin bugs, Nephila spp. spiders and butterflies (identified to species), and data on mealworm removal from each plot. Environmental data includes soil temperature readings recorded over 24 hours, information on the size of the plot, crop type and cover, GPS location, vegetation cover, vegetation height, canopy density, epiphyte cover, soil pH, soil moisture, leaf litter depth, horizon depths, palm herbivory and palm health. Social data includes information (all anonymised) on plot area, number of palms, sociodemographic data, plantation management practices applied, knowledge and value assigned to wildlife, and yield. Data were collected from December 2021 to July 2022
description: Biodiversity, environmental and social data were collected in a series of field campaigns, led by researchers from Wild Asia.

Biodiversity data collection included standard transect walks of 100 m to record the abundance and activity of butterflies, as well as numbers of Assassin bugs and Nephila spiders within a 5 m x 5 m box in front of the recorder. At four points along the transect, separated by 20 m, we also recorded understory flying invertebrate abundance and predation. Clear plastic sheets smeared with glue were used as sticky traps, suspended 40 cm above the ground and facing south, to collect understory invertebrates. Sticky traps were collected after 24 hours. Sticky traps were photographed to allow later recording of invertebrate abundance. Cards with 6 dead meal worms attached and hung on palm trunks next to sample points were used to assess predation, by recording removal over 24 hours.

Environmental data collection methods included visual inspection of plots to record the cover of different crop types and using handheld GPS units to record plantation boundaries and the size of plantations. At the same four sample points used to set pitfalls and sticky traps, we also made direct measurements of vegetation, palm and soil characteristics. These included field readings of canopy openness using a convex spherical densiometer, direct measures of vegetation height and cover (into categories by eye within a 3 m x 3 m area), and field measures of soil pH and moisture using a Suplong probe. We also scored height, health, % epiphyte cover on the trunk, and level of herbivory by eye on the closest palm to each point. We also dug small soil pits to assess leaf litter depth and then used a standard 10 cm deep and 5 cm diameter tube to collect soil samples. We also conducted a Visual Evaluation of Soil Structure (VESS) survey to measure the depth of soil horizons and associated characteristics, following standard methods.

Social data were collected through a mixture of telephone and face-to-face interviews with smallholders, at a time convenient to the smallholders. Some telephone interviews were necessary owing to the impacts of COVID. Ethical permission for interviews was gained from the University of Cambridge Department of Psychology ethics board before work took place, no information was withheld from participants and full written consent was obtained in advance.

On return to the lab, soil samples were weighed wet and then dried to a constant weight, allowing water content and soil compaction to be calculated. Sticky trap photos had insects counted and identified to order-level. 
Data were entered digitally by field teams and returned to the University of Cambridge for quality and error checking, and to ensure a standard format.