Improved "lens" reveals increased value of varied environments

Why are some places buzzing with life while others host only a few species? 
One obvious answer lies in heterogeneity— the variety in a habitat. The more variation in food sources, microclimates, and physical structures, the more niches are available for species to occupy.

But when researchers have tested this idea in real ecosystems, the results have been puzzling. Often diversity seems to level off or even decline with increased habitat variety. The diagrams have been hump-shaped or negative. There seemed to be a limit where more heterogeneity did not lead to more biodiversity anymore. 

Old method was wrong 

Now, researchers at the Swedish University of Agriculture Sciences have developed a new method of calculating the effects of variation. The new approach shows that it is the way scientists used to measure heterogeneity was wrong.  
Cameron Pellett, corresponding author to the paper published in Nature Communication explains the work as having refined the “lens” we look through to understand the environment. 
“The old lens was diffracting the light and creating distortions. Refining it allows us better see reality”, he says. 
Traditional methods are influenced by the mean average value of the variable being studied, which can distort the picture and create patterns that aren’t really there. The researchers developed a new way of measuring heterogeneity that isn’t biased by the average, it is mean independent.

Diversity actually increases 

When applied to ecological data, this new method restores the classical and most intuitive picture: more variety really does support more biodiversity. By using this mean-independent measure, ecologists can see the true relationship between habitat variety and biodiversity. 
“Now we have a clear picture that the complexity of ecosystems continues to drive increased diversity beyond what was previously thought possible”, says Professor Ruben Valbuena.  
“This will allow us to more effectively measure the complexity of ecosystems nationally or even worldwide, which can enable us to more precisely monitor progress on policies and to halt biodiversity loss”.  

Wider scientific implications 

Cameron Pellett stresses that the method also has potential to improve studies in many other scientific fields where heterogeneity plays a key role. 
“This new measure of variability is in fact more general than our ecological application, as mean bias of variability measures affects the wider science, such as the study of economic inequality”, he says. 
 
Link to Nature Communications: Disentangling dispersion from mean reveals true 
heterogeneity-diversity relationships