Jingszo !

The rule is simple: in every region on Earth, most species cluster together in small "hotspot" areas, then gradually spread outward with fewer and fewer species able to survive farther away from these hotspots.

Given the vast differences in life strategies—some species fly, others crawl, swim, or remain rooted—and the contrasting environmental and historical backgrounds of each bioregion, the researchers expected that species distribution would vary widely across bioregions. Surprisingly, they found the same pattern everywhere.

The pattern points to a general process known as environmental filtering. Environmental filtering has long been considered a key theoretical principle in ecology for explaining species distribution on Earth.