Agroforestry inside oil palm plantation for enhancing biodiversity-based ecosystem functions

Abstract

At the oil palm landscape, conserving biodiversity and ecosystem processes can range from continuous adjacent forest remnant to tree patches (agroforestry) maintained within the oil palm landscape on steep slopes and riparian margins. The objective of the research was to analyze patched of tree planting inside monoculture oil palm plantation (agroforestry) as one variant of landscape multifunctionality for enhancing biodiversity-based ecosystem functions including soil macrofauna, soil water recharge/retention, and pollinators. The observation was carried out in 2019 in agroforestry islands established in 2013 by EFForTS research project inside monoculture oil palm plantation. At the agroforestry age of 5 years in 2019, the abundance of individual soil fauna in agroforestry plots and oil palm plantation was not significantly different. The infiltration and soil big pores in agroforestry tended to be higher than in oil palm active rows. Pollinator species richness was not significantly different in all plant diversity levels and plots. Similar to its richness, pollinator abundance is neither affected in different plant diversity levels nor plots. The lack of pollinator presence may be caused by the haze from forest and land fires that happened during the research.

Tropical agroforestry supports insect pollinators and improves bean yield

“…Several studies have found that agroforestry increases the diversity and abundance of insect pollinators, and thus pollination services (Bentrup et al, 2019;Centeno-Alvarado et al, 2023;Varah et al, 2020). At the same time, other studies found that agroforestry did not affect pollinator diversity (Knowlton et al, 2019;Tarigan et al, 2021) and occasionally had lower pollinator abundance than conventional agriculture (Galbraith et al, 2020). Our results support the argument that agroforestry benefits insect pollinators and thus improves pollination services.…”

“…Some studies have shown that agroforestry increases the diversity and abundance of insect pollinators, because it offers more food and nesting resources for insect pollinators (Hoehn et al., 2010; Silva Neto et al., 2021; Varah et al., 2020). At the same time, other studies found no effect of agroforestry on pollinator diversity (Knowlton et al., 2019; Tarigan et al., 2021) and occasionally even a lower pollinator abundance than conventional agriculture (Galbraith et al., 2020). Most studies predicting the impact of agroforestry on insect pollinators have been conducted in temperate Europe and America (Centeno‐Alvarado et al., 2023; Timberlake & Morgan, 2018), which is unlikely to be globally representative and leaves the impact of agroforests in tropical East Africa largely unknown.…”

“…Some studies have shown that agroforestry increases the diversity and abundance of insect pollinators, because it offers more food and nesting resources for insect pollinators (Hoehn et al, 2010;Silva Neto et al, 2021;Varah et al, 2020). At the same time, other studies found no effect of agroforestry on pollinator diversity (Knowlton et al, 2019;Tarigan et al, 2021) and occasionally even a lower pollinator abundance than conventional agriculture (Galbraith et al, 2020).…”

“…There are several potential reasons why agroforestry does not always effectively support pollinators. One is that tree diversity in many agroforestry systems is low or agroforestry may be practiced on a too-small spatial scale, and therefore, the amount of floral resources or nest sites may not increase much compared to non-agroforestry farms (Knowlton et al, 2019;Tarigan et al, 2021).…”

“…There are several potential reasons why agroforestry does not always effectively support pollinators. One is that tree diversity in many agroforestry systems is low or agroforestry may be practiced on a too‐small spatial scale, and therefore, the amount of floral resources or nest sites may not increase much compared to non‐agroforestry farms (Knowlton et al., 2019; Tarigan et al., 2021). Another reason may be the composition of surrounding landscapes whereby landscape homogenization, as well as fragmentation and loss of natural habitat, has been shown to affect the abundance and diversity of insect pollinators, as it reduces their food and nest resources availability (Dainese et al., 2019; Klein et al., 2012).…”