Ecologist Ray Turner documented the invasion of mesquites into desert grasslands over a century.

Turner also helped document the decline of the Santa Cruz River south of Tucson over the same period.

He also documented the impacts of climate change on the Sonoran Desert long before that kind of research was fashionable.

And after Turner’s death this month following more than 60 years of groundbreaking desert research, some of his colleagues say his kind won’t be seen again. His brand of basic research involved camping and backpacking across the desert, from Southern Arizona to Kenya, to gather plant data, a far cry from contemporary researchers who look to satellite transmissions and computer models.

Turner died Dec. 9 at age 91, after suffering a stroke at a Tucson assisted living facility.

His death came roughly four years after publication of the last major book he co-authored, “Requiem for the Santa Cruz.” It chronicled the death of the Santa Cruz at the hands of Tucson’s burgeoning population.

That came almost a half-century after his first major work, “The Changing Mile,” showed how climate, livestock grazing, fire suppression and other forces had transformed the Sonoran Desert since the 1890s.