Various teams of natural history scientists had their first opportunity to survey in earnest today. Now that base-camp is set up and the little crises solved, the research has begun. Los Dolores is a large arroyo that faces eastward towards the Gulf of California. The mouth of the arroyo is a wide coastal plain that was once used for agriculture dating back to the days of the mission. The abandoned ruins of the mission are located four kilometers up the arroyo where ground water surfaces in the more narrow canyons. The arroyo is bordered in the west by thousand foot cliff faces and explains the reason why no permanent roads were ever built.

Before the expedition, Drs. Jon Rebman and José Luis León de la Luz, with the help of the SD Herbarium staff, compiled a list of all of the vascular plant taxa documented by recent and historical collections from the Agua Verde/Cerro Mechudo Corridor that have been deposited at either the SD Herbarium at the San Diego Natural History Museum or the HCIB Herbarium at the Centro de Investigaciones Biológicas del Noroeste in La Paz.

This preliminary checklist contains a total of 364 plant taxa (347 species), of which 129 taxa are endemic to Baja California Sur. With a rate of endemism close to 40 percent, the rich flora of the Agua Verde/Cerro Mechudo Corridor is indeed very special and quite unique. However, there is no doubt that many species have not yet been documented from this area so the botanical quest for the binational expedition will be to survey and collect more plants from each locality in an attempt to better assess and understand the flora of the region.

Team Botany (Drs. Jon Rebman, José Delgadillo and Mike White along with Jan Emming and Nancy Nenow) made 45 different plant collections in Arroyo Los Dolores. Most of these collections were first time records of plant species for this region of Baja California Sur. The most significant discovery of the day was a population of Eucnide tenella that was located on a travertine boulder near a spring west of the old mission ruins. This rare species is only known from a couple of populations in the Sierra de la Giganta, one of which is the type locality in a box canyon just behind the village of Agua Verde. Eucnide tenella, which is in the Loasaceae, is an annual plant with small white flowers and palmately-lobed leaves that grows mostly on steep rocky cliffs. The reproductive behavior of the species is quite interesting because after the flowers are fertilized, the pedicels (stalks) of the fruits curve back towards the vertical rock wall and elongate greatly pushing the fruits and seeds into the substrate from which the parent plant is rooted. In a sense, this species plants its own seeds back into the ground (sheer rock wall) near the parent plant which may provide the young seedlings a better chance of survival in a preferred habitat. The botany team also rediscovered the type locality of another rare plant called Euphorbia chersonesa in the spurge family (Euphorbiaceae). This species was described in the 1980’s and has only been found in a few scattered populations in the southern part of the Sierra de la Giganta.

The other scientists have been hard at work as well. Insect diversity is high and amphibians and reptiles are active. I’ll have to give the details of their activities in a future log because I’m needed in the specimen preparation tent.

Bradford Hollingsworth
Expedition Coordinator
From camp at 10:30pm
and
Jon Rebman
Team Botany Update

Over the last two days, scientists have been out surveying Los Dolores and it has been difficult to keep track of all the activities. I haven’t been able to keep up! Life in base-camp is good. Carolina Espinoza has kept everyone fed with a variety of delicious meals. We have tents scattered across the beach and people coming and going into and out of the arroyo constantly. It is a four kilometer walk to just the mission, so days are long and nights are used to organize, prep specimens, and recover.

Since I’m a part of Team Herp (includes myself, Dr. Oscar Flores, Dustin Wood, Anny Peralta, Cynthia Jauregui, Jorge Villaviencio, Maura Maher, and Tom Myers), I haven’t had the chance report on our own activities. Before I do, I would like to take a moment to say hello to everyone back at the museum, San Diego, my volunteers, and my students. The expedition is already highly productive and we are approaching a week in the field. Everyone is being well taken care of, we’ve had no medical emergencies, and the mosquitos are not too dense (no Dengue fever yet, just some heat exhaustion).

Team Herp (reptiles and amphibians) has been active in the day and at night. We have hiked into the canyons where water flows and surveyed the surrounding desert flats nearer to the coast. Activity is high considering it is November. We have been pleased with the number of animals seen in the course of the day considering that amphibians and reptiles are mostly active in the Spring. Our biggest find thus far is the abundance in which the Baja California Nightsnake (Eridiphas slevini) occurs. This rare species is known from only two dozen specimens and we have seen five within two days. These will surely add to our knowledge of this animal.

Both the Pacific Treefrog (Hyla regilla) and Red-spotted Toad (Bufo punctatus) are common in the canyons where there is flowing water. Both have recently breed and there are both tadpoles and froglets in and around the water. These species are opportunistic breeders and the Fall reproductive activity is certainly a response to last September’s hurricanes.

Other interesting finds include a Striped Racer (Masticophis lateralis). This species is common in the coastal habitats of San Diego County. However, in southern Baja California this species is considered rare. Being able to study the specimen in detail will add to our understanding of why it is not commonly seen. In addition, we have encountered two Speckled Rattlesnakes (Crotalus mitchellii). One was caught in front of the KPBS film crew, who followed the action as it was captured from beneath a rocky ledge. I’m also sending some photos along of a Baja California Gophersnake (Pituophis vertebralis) and a Baja California Spiny Lizard (Sceloporus zosteromus), which represents just a small proportion of the diversity seen thus far.

Tomorrow we plan to scale the southern cliff wall with the help of two guides. Our goal is to reach the large freshwater lakes at the top of the mountains. It should be a grueling day since the temperatures have been reaching into the mid to upper 90s.

Bradford Hollingsworth
Expedition Coordinator
From camp at 11:55pm