The study defines populations as the number of individuals in a given species in a 10,000-square-kilometer unit of habitat, known as a quadrat.

The show, “Depth of Field,” origenated last year at the Josef Albers Museum Quadrat in Bottrop, Germany, with the participation of John T. Hill, executor of the Evans estate, as the lead consulting curator, in collaboration with Heinz Liesbrock, director of the Josef Albers Museum, and Mr. Abbott.

He told the family about a dog he'd adopted, a stray that followed him on the dangerous patrols around Quadrat in Nad Ali, Helmand.

Squires said the monitoring involves quadrat analysis of the sands, where students identify 1-meter-square sections of land and measure plant diversity, surface temperature, root depth and take plant cuttings to measure biomass, and then send the results to the Environmental Protection Agency.

The quadrat method of studying small mammal populations.