Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

Abstract

Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS) river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that produces similar results is necessary in order to collect data from a wide variety of habitats.MethodsBoth kick and dredge nets were used to collect macroinvertebrate samples at 16 riverine sites in Zambia, ranging from backwaters and floodplain lagoons to fast flowing streams and rivers. The data were used to calculate ZISS, diversity (S: number of taxa present), and Average Score Per Taxon (ASPT) scores per site, using the two sampling methods to compare their sampling effectiveness. Environmental parameters, namely pH, conductivity, underwater photosynthetically active radiation (PAR), temperature, alkalinity, flow, and altitude, were also recorded and used in statistical analysis. Invertebrate communities present at the sample sites were determined using multivariate procedures.ResultsAnalysis of the invertebrate community and environmental data suggested that the testing exercise was undertaken in four distinct macroinvertebrate community types, supporting at least two quite different macroinvertebrate assemblages, and showing significant differences in habitat conditions. Significant correlations were found for all three bioassessment score variables between results acquired using the two methods, with dredge-sampling normally producing lower scores than did the kick net procedures. Linear regression models were produced in order to correct each biological variable score collected by a dredge net to a score similar to that of one collected by kick net sampling.ConclusionsThe use of a dredge net in macroinvertebrate bioassessment schemes is an effective, alternative method in certain environments when site conditions prohibit the use of the preferred kick net sampling method. The results of this study can be used to aid in the development of other tropical freshwater bioassessment schemes around the world, including Brazil.

Niche-breadth of freshwater macrophytes occurring in tropical southern African rivers predicts species global latitudinal range

“…Abundance was scored on a five-point scale: 1 = 1 individual present in the sample; 2 = 2-10; 3 = 11-100; 4 = 101-1000; 5 = >1000 animals present in the sample. At some sites where kick-net sampling was considered to be too hazardous (owing to deep or fast-flowing water, or an unacceptably high risk from dangerous animals, notably crocodile and hippopotamus) dredge-net sampling was undertaken, and data from these samples were recalibrated (Moore and Murphy, 2015) to permit comparative use with data from kick-sampled sites. Both kick-and dredge-nets had 1 mm mesh size.…”

Impacts on freshwater macrophytes produced by small invertebrate herbivores: Afrotropical and Neotropical wetlands compared

“…Disturbance: expressed on a semi quantitative scale of 1 = no disturbance due to trampling by animals, to 4 = major trampling damage. In Afrotropical sites, turbidity is shown as underwater photosynthetically-active radiation (PAR) absorbance coefficient: k m -1, with depth (m) at which the deeper of the two underwater PAR measurements was taken (not the maximum depth of the waterbody: Moore and Murphy, 2015). In Neotropical sites turbidity was measured as Secchi depth (m), with maximum water depth (m) also given.…”

“…Trampling damage to macrophyte vegetation, produced by mammalian herbivores, was scored on a semi-quantitative scale of 1 = no disturbance due to trampling by animals, to 4 = major trampling damage. Water turbidity, which is affected by resuspension of sediments caused by large-animal trampling disturbance of waterbody substrates, was recorded in the Afrotropical sites as photosynthetically-active radiation (PAR) absorbance coefficient: k m -1 , calculated from PAR measurements taken using an underwater PAR sensor at two points in the water column: just below surface and at a standard depth, usually 0.22 m (Moore and Murphy, 2015). In the Neotropics, water turbidity was recorded as Secchi depth (m), considering also maximum water depth (m) as a complement of this variable.…”

Assessment of Water Quality Parameters and Aquatic Insect Assemblages in Dalvoy Lake, Mysore District, Karnataka, India.

“…10 Several investigations have been conducted to explore the use of aquatic insects as bio-monitoring tools for assessing water quality. 11,12,13 Mysore is a well-known tourist destination in India, located at the foot of the Chamundi Hills in the southern state of Karnataka. The city is adorned with many small and medium-sized lakes.Among the popular lakes are Kukkarahalli Lake, Devanoor Lake, Lingambudi Lake, Dalvoy Lake, and Karanji Lake.…”