Effects of forest conversions to oil palm plantations on freshwater macroinvertebrates: a case study from Sarawak, Malaysia

Abstract

Oil palm plantations in Malaysia are expanding rapidly due to global oil and biofuel demand. This is of particular concern, as the conversion process of forested land to oil palm plantations and the maintenance of a plantation can significantly alter freshwater ecosystems. This is a result of the initial loss of a forested catchment, particularly the riparian vegetation, changes to the bed and banks of streams, sedimentation and changes to detrital inputs. In addition, various chemicals used on the plantations leach into the nearest waterways and can potentially affect freshwater macroinvertebrates. In the Malaysian region, these are largely endemic and generally incompletely known. This study assesses the impact of oil palm plantations on stream macroinvertebrates by comparing four steams flowing through undisturbed rainforest and four streams flowing through oil palm plantations in Sarawak, Malaysia. Freshwater macroinvertebrates were sampled using the standard three-minute kick sample method with accompanying chemical measurements. Although there were no distinct differences between the control and oil palm streams in the chemical data, the invertebrate communities provided a different interpretation of stream quality. Invertebrates were more abundant, species rich and diverse in rainforest streams than in oil palm ones. Most noticeably, two whole orders of insecta, Coleoptera (beetles) and Hemiptera (true bugs), were absent from the oil palm streams. This may be the result of the disappearance of natural bank habitats, the sensitivity to the pesticides targeted at the Rhinocerous beetle (Oryctes rhinoceros), or a combination of both.

Escenario futuro de cobertura de palma africana en el Ecuador para evaluar su impacto en la calidad del aire de Quito

“…Se han documentado diversos efectos de este cultivo, como el impacto en la pérdida de biodiversidad, al reemplazar zonas de bosque primario y de alto valor ecológi-co [4,5]; efectos en la población de macroinvertebrados en cuerpos de agua dulce [6], o potenciales impactos de sus emisiones en la calidad del aire [2,7].…”

Water Quality and Aquatic Insects Study at the Lower Kinabatangan River Catchment, Sabah: In Response to Weak La Niña Event

“…In addition, low abundance of aquatic insects could be resulted from high concentrations of suspended sediment, which is a significant factor in determining the complexity of food web and consequently reflected the effect of pollution (Yule et al 2010). In selected rivers in Kuching, Sarawak, lower abundance and diversity of aquatic insects was found in oil palm plantations, compared to primary forest, which could be resulted from high concentration of suspended sediment and pesticide contamination (Mercer et al 2013).…”

“…Various ecological studies have highlighted the relationship between water quality and aquatic insects in Malaysia (Mohd. Rasdi et al 2012;Wahizatul et al 2011;Yap & Rahim 2011), while some of the recent studies reported: Effects of land use changes to aquatic insects (Al-Shami et al 2011;Che Salmah et al 2013;Jinggut et al 2012;Mercer et al 2013); seasonal variations of Ephemeroptera, Plecoptera and Trichoptera (EPT) (Suhaila et al 2012) and influence of canopy cover and substrate embeddedness to EPT distribution (Suhaila & Che Salmah 2014). However, to date, there is still a huge gap in the knowledge of aquatic insects and ecological understanding of the tropical streams (Al-Shami et al 2011).…”

“…nitrogen and phosphorus). Furthermore, Azrina et al (2006) reported that oil palm plantations and sewage wastes are among the main contributors to pollutants in Langat River, while recently, Mercer et al (2013) found that stream invertebrate community in oil palm plantations in Sarawak was less abundance and diverse compared to rainforest streams.…”

“…They are mainly characterised by seasonal inundation (Hamilton 2002;Mayora et al 2013), received high solar radiation (Saigusa et al 2008) and rich in biodiversity (Bruford et al 2010). However, deforestation, active land development, land conversion for mechanized agriculture such as oil palm plantations (Mercer et al 2013), industrial and domestic waste discharge (Azrina et al 2006) often contribute to river water quality deterioration in the tropical regions. In Malaysia, rainforest conversion to cocoa and oil palm plantations in Bukit Tekam, Pahang circa 1977and 1986(Douglas 1999 and Sabah (Jakobsen et al 2007) was showed to increase surface run-off, suspended sediment loads and nutrients (i.e.…”