There's nothing like spending time in New Mexico to make you contemplate the West's long and tumultuous history and confront the thorny question: Just who is a native?

William "Sonny" Weahkee qualifies. He's a Pueblo Indian and Albuquerque activist who directs the SAGE Council, which fought for a decade alongside Anglo environmentalists against a proposed road splitting Petroglyph National Monument in two. This fall, Weahkee showed me the recently completed road, as well as the basaltic bench where his ancestors carved petroglyphs hundreds of years ago.

The list of natives would also include Jerry Ortiz y Pino, a state senator and social worker from Albuquerque who traces his roots in New Mexico back to the 17th century. Ortiz y Pino told High Country News board member Luis Torres and me that his earliest known ancestor journeyed to Spain to meet with the king and report on how things were going in the New Mexico colony. His report, according to Jerry, went something like: "We are poor; please send more money and supplies."

On the surface, Malcolm Ebright, a ponytailed Anglo who has only lived in the state for decades, would seem to be a non-native. Yet he's dedicated his life to researching and writing about New Mexico's history. In his most recent book, The Witches of Abiquiu, Ebright writes about the yeasty cauldron of humanity that inhabited the northern part of the state in the 1700s, including Spanish settlers, Pueblo Indians, raiding and trading tribes from the Great Plains, and an overlooked group of Hispanicized Native Americans known as the Genizaros, who were caught in the middle.

Ebright has used his historic findings to help the descendents of these people establish their rights to land and water. I would consider Ebright a new native because, like so many others who have come to New Mexico, he has found a niche and settled in. The same could be said for the non-human exotic species that have come to the West and found a fertile place to thrive. Some 150 years ago, Anglo settlers in California introduced tamarisk, a water-loving shrub from Eurasia, to help stabilize river banks and railroad beds. As Michelle Nijhuis reports in our cover story, tamarisk has now spread to nearly every river drainage in the West, and become a scourge to water managers, recreational boaters and bird-watchers. Efforts to cut and poison it have had only limited success, so now scientists have placed their hopes on the introduction of another non-native species, a small tamarisk-eating beetle collected from the plant's native habitat in Kazakhstan.

The damage the beetles are now inflicting on tamarisk stands could lead one to hope that the shrub might soon be sent packing back to Kazakhstan, where it belongs. But, as Nijhuis reports, that's probably not going to happen. In fact, most scientists predict that the tamarisk and the beetles will eventually reach an accord of sorts - a balanced place of mutual survival, as predators and prey species tend to do.

So should we start calling the tamarisk a native? In human terms, 150 years is a long time to have lived in the West. Many third- and fourth-generation ranchers with "Colorado Native" license plates on their trucks cannot claim as much.

Like the weeds we long to eradicate, we are hardwired to seek better habitat. And once we find a place that works, and we stick around long enough to prove ourselves, we want to be considered natives. Maybe it's time to extend that courtesy to all inhabitants of the West.