Sevilleta National Wildlife Refuge is an impressive place. It’s located between Albuquerque and Socorro, spanning the entire Rio Grande Rift from the Los Pinos Mountains on the east to the Ladrone Mountains on the west. Most of it is closed to the public, except one weekend a year.
I found out about the open house through Earth Matters, a newsletter published by the New Mexico Bureau of Geology and Mineral Resources. I started getting it in dead tree form some years ago; I think they decided to send it to all of us who subscribed to New Mexico Geology. Now I see that both are available on the Web.
The open house offered tours both days of last weekend, but Sevilleta is a two-hour drive for me, and I didn’t want to stay overnight, so I settled for a full Saturday: the Chihuahuan Desert Native Plant Walk in the morning and the Geology East Field Trip in the afternoon. Morning tours came with a breakfast burrito, and afternoon tours came with lunch of a giant chalupa assembled as you watched, to your taste, by members of the La Joya Community Development Association. Red chile, rather than green, becomes the culinary focus as you move south along the Rio Grande Valley, but I tried both. I arrived too late for the breakfast burrito, but I had eaten a light breakfast before I left.
I brought along my latest issue of New Mexico Geology, because its main feature was an article about Cretaceous strata in Sevilleta. Little did I know that one of the authors of that article (Stephen Hook) would show us exactly where he collected his materials for the article. (The article has a good map of Sevilleta in it.)
I have a particular interest in ammonites. Two large and heavy ones sit just outside my front door. John Fowles, in The French Lieutenant’s Woman, uses them nicely to represent the past that is gone and mysterious. I bought a small one when I visited Lyme Regis, Fowles’s home.
Ammonites not at all like my doorway ammonites are used to indicate the various parts of the Cretaceous Era, and all of them are found in a rather short sequence of sediments at Sevilleta. I didn’t learn the relationship of mine (collected near Galisteo) to those at Sevilleta, but I do love the names of those times: Cenomanian, Turonian. So musical.
I hadn’t realized that the Chihuahuan Desert life zone extended so far north into New Mexico. Sevilleta’s Chihuahuan zone is more of a grassland, short-grass prairie environment. The grass is quite thick, many kinds. I am beginning to think that some of the larger grasses in my yard, which I’ve been thinking of as big bluestem (Andropogon gerardi) is actually giant sacaton (Sporobolus wrightii), or possibly one of the dropseeds (also Sporobolus species). I’ve never been very observant of grasses and need to do some learning.
Lovely cactus, of course.
The Chihuahuan zone has extended about twenty miles north in the last twenty-thirty years, so that Albuquerque is now on its edge. There was a great deal of mesquite, which I don’t recall from my many trips to Bosque del Apache, some tens of miles to the south. That’s one of the markers of the Chihuahuan zone. I’m more accustomed to thinking of it around Tucson and Phoenix.
The University of New Mexico has a number of long-term ecological experiments operating in Sevilleta. It’s not my primary field of research, but I was involved at the fringes of some of the early experiments of that sort. Signs on the plots gave some indication: mycorrhyza in the soil, interaction of fungus in prairie-dog burrows, transpiration and evaporation of water, and even a study of how the prairie dogs that were transferred from the Santa Fe airport are adjusting.
It was a delightful day. The scenery photo doesn’t do the area justice. I think it was Robert Pirsig who said that something disappears when you put a frame around this scenery.
Photos (all by CKR): Ladrone Mountains from about the center of Sevilleta NWR.
Burrows in the Cretaceous mud (about finger’s width).
Impressions of plant detritus, probably in a swampy environment
Echinocereus (hedgehog) cactus in grass and rocks.
Desert marigold (Baileya multiflora). They were everywhere in this area, scenting the air beautifully.