Water quality dynamics in a lowland tropical catchment: the Kinabatangan river, Sabah, Malaysia

Spatial and temporal trends of dissolved organic matter (DOM) were investigated in the Lower Kinabatangan River, Sabah, Malaysia over the period 2008-2012. The objectives were to: i. quantify DOM in areas of the catchment dominated by oil palm plantations; ii. characterise DOM quantity and quality in waters draining three contrasting land use types (oil palm plantations, secondary forests and coastal swamps); iii. characterise and interpret DOM quantity and quality in the main stem of the Kinabatangan river according to depth; and iv. infer differences in water movement through the catchment. Optical parameters, including fluorescence excitation-emission matrices (EEMs) and ultraviolet absorbance spectroscopy (UV-vis); and Parallel Factor Analysis were used throughout the investigation. The research comprised a preliminary catchment-wide study (225 samples) and concentrated fieldwork campaigns (510 samples). The results indicated the dominance of peaks C and M in waters from the oil palm plantations and coastal swamps respectively. The relative loss of terrestrial derived peaks could indicate progressive DOM degradation from the upper reaches towards the estuary. Results also showed DOM was transported back to the main river, as dominated by fluorescence index peak A/peak C, particularly in the coastal swamps. DOM characterisation with depth in the river, showed the dominance of peaks C and M (relative to terrestrial and microbial and/or photo-degradation processes) in waters near the riverbed

Water quality monitoring in Sugut River and its tributaries

WWF-Malaysia initiated the water quality monitoring using physic-chemical and biological parameters along the lower Sugut River and its tributaries to monitor the status of water quality in the area, especially in areas surrounded by oil palm plantations. A total of 12 sampling stations were selected at four tributaries of Sugut River based on agreement with WWF staff members and Sabah Forestry Department (SFD) officer. The four tributaries were Sabang river (next to oil palm mill), Sugut river (next to oil palm plantation), Wansayan river (next to secondary forest) and Kepilatan river (next to Nipah forest). Fieldwork started in August 2015 and ended in November 2015, with a total of four samplings. The results showed that the Water Quality Index (WQI) classified Sg. Sabang as very polluted, while Sg. Sugut, Sg. Wansayan and Sg. Kepilatan were slightly polluted. In accordance to INWQS, parameters TSS, DO and BOD for all tributaries were classified in Class III and IV. Table 3 summarizes the mean concentrations for each physico-chemical parameter at each tributary. Parameters TSS, TDS, COD, ammonia nitrogen, conductivity and salinity were found the highest at Sg. Sabang, followed by Sg. Kepilatan, which could be due to salinity effect. It also possibly caused by accumulation of sediments and nutrients, as estuary area has been reported constantly receives organic matter from inflowing tributaries (Day et al., 2007). COD was the highest at Sg. Sabang, and this parameter is known to represent total organic matter in water bodies (Hur & Cho, 2012). The monitoring work presented in this report represents a baseline data on the water quality of Sugut River basin by using physico-chemical and biological parameters. It is recommended that development in the upper reaches of the Sugut river should be monitored to ensure that the quality of the river does not get worse. The next step would also be to engage with the oil palm plantation companies along the river to look at ways to mitigate river pollution

Water quality and phytoplankton distribution of the Lower Kinabatangan River Catchment, Sabah

A study on water quality and phytoplankton distribution was carried out at the Lower Kinabatangan River Catchment, Sabah in November 2013, January 2014 and March 2014. The objectives were to study the surface water quality of the Lower Kinabatangan River Catchment; to identify the composition of phytoplankton in three different types of land use in Sukau, Kinabatangan; and to determine spatial and temporal variations of water quality in Sukau, Kinabatangan. Three sampling stations were selected to represent different types of land use, consisting of oil palm plantation (OP), secondary forests (SF) and oxbow lake (OB). Based on Interim National Water Quality Standards (INWQS) for Malaysia, the parameters were categorized within Class I to Class IV. Statistical analyses ANOVA one-way, paired sample t-test and discriminant analysis have been carried out to both water quality and total monthly precipitation data sets. The distribution of phytoplankton in Kinabatangan River consisted of 5 divisions: the Bacillariophyta, Chlorophyta, Cyanophyta, Cryptophyta and Euglenophyta. Chlorophyta recorded the highest diversity, with 10 species recorded out of 17 species found of the Lower Kinabatangan River Catchment. Discriminant analysis suggested that UV-visible absorption coefficients at 254 and 340 nm were dominant in samples from OP and SF. Temporal variations showed that parameters suspended sediment, UV-visible absorption coefficients at 254 and 340 nm were dominant in samples from collected in January 2014

Biomonitoring of streams: using Ephemeroptera, Plecoptera And Trichoptera (Ept) in responses to the different types of land use at Tabin Wildlife Reserve (TWR), Lahad Datu, Sabah, Malaysia

A preliminary study on three aquatic insect orders, namely Ephemeroptera (mayfly), Plecoptera (stonefly), and Trichoptera (caddisfly) (EPT) was conducted at Tabin Wildlife Reserve (TWR), Lahad Datu, Sabah in January and February 2015. The objectives of this study were to determine (i) the composition of EPT along a stream at TWR, (ii) the distribution of EPT in each different land use at TWR, and (iii) the relationship between EPT communities and the water quality of the stream at TWR. Kick net sampling technique was used for collecting the EPT communities along Sg. Lipad of TWR. The most dominant order was Ephemeroptera consisting of 11 families with 1,354 individuals out of the total of 1,724 individuals and 26 families of EPT communities sampled. Trichoptera was the second most abundant order with nine families and 258 individuals, and lastly, Plecoptera with only six families and 112 individuals. There were more families of EPT communities distributed in secondary forest as compared to the oil palm plantation. Several exclusive families were found in secondary forest, while only one family was found in oil palm plantation. The habitat run showed the highest in abundance of EPT, while pool recorded the least in abundance. Four biotic indices (BMWP, ASPT, FBI, and INWQS) and a few physico-chemical parameters (pH, temperature, conductivity, and DO) were used in this study to determine the water quality of the sampling location. Based on the biotic indices and physico-chemical parameters, the status of water in Sg. Lipad was in excellent condition. The two water quality tests showed profound consistency. This serves as a confirmation that the EPT communities are effective to be used as a biomonitoring tool at TWR

The aquatic invertebrates’ assemblages’ responses to watershed land use in Tabin Wildlife Reserve (TWR), Lahad Datu, Sabah, Malaysia Borneo Science

A study on the aquatic invertebrate communities was conducted at Tabin Wildlife Reserve (TWR), Lahad Datu, Sabah, with the objectives to study (i) the diversity of aquatic invertebrates across different land use, (ii) the composition of aquatic invertebrates in different habitats and microhabitats in the stream, and (iii) the relationship between invertebrates and the water quality of the stream. Sampling was done at Sg. Lipad which flows across the secondary forest area and plantation area. Kick net method was used to sample the aquatic invertebrates for 14 continuous days in January to February 2015. A total of 3,579 individuals were sampled consisting of 76 families from eight orders, in both of the land uses. The diversity of aquatic invertebrates in the secondary forest was found to be slightly higher than plantation area with H’= 3.213 and H’= 3.188 respectively. The aquatic invertebrates were also found to be more abundant in riffle habitat, and the least in pool habitats. The diversity for pool habitat, however, was the highest among all other habitats with H’= 3.709. Both physico-chemical parameters and biotic indices indicated that the invertebrate communities were affected by the water quality in the surroundings, and may be used for rapid assessment of water quality at TWR

Aquatic Insects and Water Quality Study at Kimanis River, Crocker Range National Park, Sabah, Malaysia

A survey on the aquatic insect communities was conducted in Kimanis River, Ulu Kimanis, Crocker Range Park (CRP), Sabah with the objectives to study (i) the composition of stream insect communities, (ii) stream water quality and (iii) the relationships between aquatic insects and freshwater quality parameters in Kimanis River, Ulu Kimanis, CRP. The sampling was carried out using surber net in October 2015 and January 2016. A total of 1,801 individuals from nine orders of 28 families were collected from Kimanis River. Trichopterans fauna was found to be the prominent taxa in this study. Shannon-Wiener Index of upstream strata was recorded slightly higher than downstream strata with H’= 1.97 and H’= 1.85 respectively. Water integrity of Kimanis River could be considered as excellent with minimal pollution. Both water quality parameters and biotic indices indicated that the aquatic insect population was affected by the water quality in their surroundings. This proved the use of aquatic insect communities as bioindicator for rapid assessment of water quality in CRP

Current and future effects of global change on a hotspot's freshwater diversity

Deforestation, climate change and invasive species constitute three global threats to biodiversity that act synergistically. However, drivers and rates of loss of freshwater biodiversity now and in the future are poorly understood. Here we focus on the potential impacts of global change on freshwater mussels (Order Unionida) in Sundaland (SE Asia), a vulnerable group facing global declines and recognized indicators of overall freshwater biodiversity. We used an ensemble of distribution models to identify habitats potentially suitable for freshwater mussels and their change under a range of climate, deforestation and invasion scenarios. Our data and models revealed that, at present, Sundaland features 47 and 32 Mha of habitat that can be considered environmentally suitable for native and invasive freshwater mussels, respectively. We anticipate that by 2050, the area suitable for palm oil cultivation may expand between 8 and 44 Mha, representing an annual increase of 2–11%. This is expected to result in a 20% decrease in suitable habitat for native mussels, a drop that reaches 30% by 2050 when considering concomitant climate change. In contrast, the habitat potentially suitable for invasive mussels may increase by 44–56% under 2050 future scenarios. Consequently, native mussels may compete for habitat, food resources and fish hosts with invasive mussels across approximately 60% of their suitable range. Our projections can be used to guide future expeditions to monitor the conservation status of freshwater biodiversity, and potentially reveal populations of endemic species on the brink of extinction. Future conservation measures—most importantly the designation of nature reserves—should take into account trends in freshwater biodiversity generally, and particularly species such as freshwater mussels, vital to safeguard fundamental ecosystem services.This study is funded by the Malaysian Ministry of Higher Education (Project FRGS/1/2015/WAB13/UNIM//1). BG was supported by a research fellowship funded by the Spanish Program of R + D + I (JCI2012-11908)

Changes and drivers of freshwater mussel diversity and distribution in northern Borneo

Human activities are threatening Borneo's unique biodiversity, but little is known on the status of freshwater invertebrates. We assessed changes in diversity and distribution of freshwater mussels (Bivalvia: Unionida) in northern Borneo, and identified drivers of present distribution and threats. Past distribution data were collected from literature and museum resources. Present distribution data were collected from 21 river basins, and 47 water quality, climatic, landscape and human variables explored as potential predictors of species presence/absence. Species delimitations were identified by morphology and COI barcoding, and haplotype networks generated. Our data indicate that over the past 50 years, four of originally five native species have become very rare or possibly locally extirpated. Since these four species are endemic to Borneo, other Bornean river basins should urgently be surveyed to identify any remaining populations. In the same time span, the non-native Sinanodonta woodiana has become the most widespread freshwater mussel in northern Borneo. The fifth native species was identified as Rectidens sumatrensis and found in four Sarawakian river basins, thus contradicting previous assumptions of an endemic Bornean Rectidens species. Although a number of stable R. sumatrensis populations are retained across Sarawak, the species' strong spatial contraction in mainland Sundaland and apparent low tolerance to eutrophication suggest that it is vulnerable to further habitat alteration. Our results indicate that Borneo's (endemic) freshwater invertebrate biodiversity is declining rapidly. Comprehensive surveys targeting an array of invertebrate and vertebrate taxa are needed to identify Borneo's freshwater biodiversity hotspots, where conservation efforts should be concentrated

Water quality and aquatic insects study at the Lower Kinabatangan River Catchment, Sabah: in response to weak La Niña event

A study on water quality and aquatic insects has been conducted at the Lower Kinabatangan River Catchment, Sabah, Malaysia. The quality of water surface and aquatic insects’ composition were studied in streams near to oil palm plantation (OP), secondary forest (SF) and oxbow lake (OB). The study also aims to identify the seasonal variation in the aquatic insects’ composition during the weak La Niña event. A total of 135 water samples and 1678 aquatic insect individuals (four orders and 14 families) were collected during fieldwork campaign that spanned over the inter-monsoonal period, wet and dry seasons between October 2004 and June 2005. OP has the highest abundance of aquatic insects particularly during the dry season. Biological indices showed that all stations were in moderate water category. The water quality index (WQI) was calculated and indicated that the quality of the river categorised into Class II. Discriminant analysis (DA) was employed to classify the independent variables into mutually-exclusive groups. Suspended sediment (SS) and chemical oxygen demand (COD) were high during the wet season. Suspended sediment was high in oxbow lake and could be a strong reason behind low abundance of aquatic insects. Precipitation anomalies were found to affect seasonal variations of water quality and aquatic insects at the Lower Kinabatangan River

Spatial and seasonal variations in the composition of dissolved organic matter in a tropical catchment: the Lower Kinabatangan River, Sabah, Malaysia

International audienceDissolved organic matter (DOM) was characterised in water samples sampled in the Lower Kinabatangan River Catchment, Sabah, Malaysia between October 2009 and May 2010. This study aims at: (i) distinguishing between the quality of DOM in waters draining palm oil plantations (OP), secondary forests (SF) and coastal swamps (CS) and, (ii) identifying the seasonal variability of DOM quantity and quality. Surface waters were sampled during fieldwork campaigns that spanned the wet and dry seasons. DOM was characterised optically by using the fluorescence Excitation Emission Matrix (EEM), the absorption coefficient at 340 nm and the spectral slope coefficient (S). Parallel Factor Analysis (PARAFAC) was undertaken to assess the DOM composition from EEM spectra and five terrestrial derived components were identified: (C1, C2, C3, C4 and C5). Components C1 and C4 contributed the most to DOM fluorescence in all study areas during both the wet and dry seasons. The results suggest that component C4 could be a significant (and common) PARAFAC signal found in similar catchments. Peak M (C2 and C3) was dominant in all samples collected during wet and dry seasons, which could be anthropogenic in origin given the active land use change in the study area. In conclusion, there were significant seasonal and spatial variations in DOM which demonstrated the effects of land use cover and precipitation amounts in the Kinabatangan catchmen