Dr Dalu was invited to speak at the Fall 2024 instalment of the series, hosted by LSU’s Department of Biological Sciences. The seminar provides a platform for distinguished experts in systematics, ecology, and evolution to present cutting-edge research.
“I was invited to present at LSU as part of their 2024–2025 seminar series, which traditionally features US-based speakers. I am proud to be one of only four guest speakers this year and the first international presenter,” said Dr Dalu.
His presentation, titled: “Salinisation and Warming Impacts on Trophic Interactions in Temporary Wetland Systems,” showcased his pioneering research on how environmental stressors – particularly salinity and rising temperatures – affect biodiversity and the functioning of temporary wetlands. The topic is highly relevant in light of climate change and human-induced environmental impacts, which pose significant threats to ecosystems worldwide.
His research focuses on how climate-related changes impact species interactions in wetlands, which are critical ecosystems for maintaining biodiversity and providing essential services.
“This work specifically targets temporary wetlands, which undergo cycles of drying and re-flooding, creating a fragile and dynamic environment,” he explained.
Dr Dalu's inclusion in the LSU seminar series marks a significant achievement for African scholars in Environmental Science.
Key Research Findings
Dr Dalu’s research highlights the profound effects of environmental changes on wetland ecosystems, home to a variety of species, particularly crustaceans, which rely on dormant egg production for their survival.
His findings show that salinity levels above 2.5 parts per thousand (ppt) significantly reduce both species richness and abundance. Two taxa, Spinicaudata and Ostracoda, were found to be especially sensitive to elevated salinity levels.
In addition to decreasing species richness, increased salinity also disrupted hatching dynamics. Under saline conditions, most species experienced reduced hatching success over time. However, Dr Dalu observed that Cladocera – a key group of crustaceans – displayed an unusual response: their hatching rates peaked 20 days after inundation, in contrast to other groups, which showed declining hatchability.
Temperature also played a complex role in his findings. While rising temperatures typically boosted predator feeding rates, the combination of high temperatures and increased salinity led to unexpected outcomes.
“Higher salinity suppressed the temperature-driven increase in feeding activity, resulting in significant alterations to the food web and trophic interactions within these ecosystems,” Dr Dalu explained.
He warned that the combined effects of salinisation and warming are likely to reduce species recruitment, alter predation pressures, and disrupt food web dynamics. “These changes threaten the stability of ecosystem services and could lead to cascading effects on biodiversity,” he noted.
Global Recognition of African Scholarship
Dr Dalu's inclusion in the LSU seminar series marks a significant achievement for African scholars in Environmental Science, highlighting the growing recognition of their contributions to global research.
Story by Cleopatra Makhaga. Pictures supplied.