We might be underestimating the detrimental effects of human activities on our plant and animal species around the world due to a commonly used scientific method applied in research on the subject, according to a new study by Lancaster University researchers.
Scientists conduct the majority of ecological impact studies when disturbance events, such as fires and logging, have already occurred. This forces them to use undisturbed sites in nearby areas in order to estimate what the disturbed area looked like before and after the disturbance event, a scientific method known as space-for-time substitution.
In conjunction with Brazilian colleagues, the team headed to the Amazon forest and obtained measurements of dung beetle species diversity before and after a disturbance event - logging exploration - in order to determine the effectiveness of the experimental common method. Overall, the team sampled 4,846 dung beetles across 34 different plots of land in the forest.
The results revealed that when using the space-for-time substitution scientific method, which is very common, species loss was underestimated by up to half. The finding sheds light on the downfalls of the common technique and the consequences of land-use changes and disturbances on biodiversity loss in tropical forests.
"The significantly weaker effects revealed by the space-for-time approach are of great concern: this is the most commonly used method of assessing the biological consequences of selective logging on tropical invertebrates and underpin most assessments of biodiversity and ecosystem functioning losses caused by anthropogenic forest disturbances," the researchers wrote.
"We provide important evidence that the use of space-for-time assessments may underestimate the impacts of human-induced forest disturbances on biodiversity loss," said Filipe França, researcher from Lancaster University and first author of the study. "Additionally, we demonstrate that sharp losses in species diversity and dung beetle biomass occurred particularly at high logging intensities."
"Although our comparison is restricted to a single taxa and a single disturbance event, the magnitude in the scale of the effects suggests that the potential issues of could apply to other anthropogenic disturbances and other taxa," he added.
The findings were published in the April 22 issue of the Journal of Applied Ecology.