Title: Using Habitat Structure and Macroinvertebrate Communities towards developing a typology for waterpans in Lower Mara, Narok County, Kenya.

Author: John Otieno Olang

Supervising Institution: IHE Delft Institute for Water Education

Year: 2025

 

Abstract:

Waterpans are aquatic ecosystems that receive water through precipitation and runoff and lose water mainly through evaporation. They play certain roles in ecological processes such as soil nutrient cycling, hydrological cycle, carbon storage, maintaining water quality, and groundwater inputs as well as biodiversity conservation. However, despite being an important aquatic resource, waterpans in East Africa have received limited monitoring and ecological research. The study was conducted in Lower Mara in Narok County, Kenya in 13 different waterpans to assess habitat structure and the macroinvertebrate composition.
Macroinvertebrate sampling was conducted using kick sampling and identified to the lowest taxo-nomic level possible while sediment grain sizes and vegetation were collected using systematic sam-pling. Morphometric features of waterpans were also collected during the sampling. The macroin-vertebrate data were analyzed using the Kruskal-Wallis test, Bray-Curtis NMDS and Hierarchical dendrogram in R statistical software, while grain sizes were converted to phi (φ) and further analyzed using Spearman’s Rank Correlation. Additionally, vegetation data were analyzed using DAFOR scales. Hypsographic curves illustrated the distribution of surface area under different depths.
The macroinvertebrates analysis revealed that the distribution of taxa richness across categories of meso-habitats is significantly different (P = 0.001, P < 0.05). The dendrogram test results indicated homogeneity of meso-habitats within the waterpans. Thus, classifying waterpans into marginal wa-terpan, marginal sediment, open shore and open sediment waterpans. The phi (φ) sediment results indicated a significant weak positive correlation between average taxa richness and Phi (φ) for sed-iments (r = 0.232, p < 0.01). Moreover, the DAFOR scores for vegetation indicated different results for species across sites, resulting in the vegetation-based classification of different waterpans into sedge pan, grass pan and open waterpan. Finally, Hypsographic curves showed that larger surface areas of the waterpans are under shallow depths.
The findings from this study emphasize the role of waterpans in supporting biodiversity in arid and semi-arid areas. Thus, there is a need to develop ecological integrity protocols for monitoring, which can be achieved by harmonizing existing protocols.

 

Keywords: Biomonitoring, Meso-habitat, Ephemeral, Perennial, Pans, Hydroperiods, Habitat struc-ture, Phi (φ) Sediment, Macroinvertebrates, Arid and Semi-Arid, Homogeneity, Heterogeneity, Hyp-sographic curves, Microhabitats, Marginal, Open shore, DAFOR scale, Vegetation, Typology, Sedge pan, Grass pan, Open pan, Endorheic systems, Diversity