Preliminary testing of the Integrated Habitat Assessment System (IHAS) for aquatic macroinvertebrates

  • Dean J Ollis Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa Current address: Freshwater Research Unit, Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
  • Charles Boucher Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa Current address: 18 Patrys Street, Stellenbosch 7600, South Africa
  • Helen F Dallas Freshwater Research Unit, Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
  • Karen J Esler Department of Conservation Ecology and Entomology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
Keywords: invertebrate habitat assessment, Mpumalanga, river assessment, South Africa, South African Scoring System (SASS), Western Cape

Abstract

Preliminary testing of the Integrated Habitat Assessment System (IHAS), a widely-used aquatic macroinvertebrate habitat assessment method in South Africa, was undertaken. Based on the sensitivity of the South African Scoring System (SASS) to biotope availability and assuming that SASS Scores at minimally-impacted reference sites are the highest Scores attainable, one would expect to find a positive relationship between SASS Scores and IHAS scores at reference sites. The preliminary testing undertaken is based on the assumption that this relationship should be linear. For data obtained from reference sites in Mpumalanga and the Western Cape, non-parametric correlation analyses were undertaken between SASS4/5 Scores and IHAS scores, using Kendall's Rank-correlation Coefficient. Separate analyses were undertaken for different geomorphological zones and biotope groups. Results were generally unsatisfactory, with non-significant correlations (P > 0.05) for two-thirds of the data sets analysed. Performance of the IHAS varied between geomorphological zones and biotope groups, with best results obtained for the Foothill: Gravel-bed Zone in Mpumalanga, particularly with the stones-in-current biotope analysed separately. Further testing is required to confirm the relative performance in different bioregions/ecoregions, geomorphological zones and biotope groups.

Keywords: invertebrate habitat assessment, Mpumalanga, river assessment, South Africa, South African Scoring System (SASS), Western Cape

African Journal of Aquatic Science 2006, 31(1): 1–14
Published
2006-08-01
Section
Articles

Journal Identifiers


eISSN: 1727-9364
print ISSN: 1608-5914