San Diego Natural History Museum--Your Nature ConnectionSDNHM Biodiversity Research Center of the Californias

Pines on western side, photo by Thomas A. Oberbauer © 1998
Pinus radiata var. binata growing along the unexplored western side of the island. Photo by Thomas A. Oberbauer © 1998. All rights reserved.

Cistanthe guadalupensis, photo by George Lindsay 1948
Cistanthe guadalupensis, on rocks off the south end of Guadalupe Island. Photo by George Lindsay, 1948.

Brahea edulis, photo by Reid Moran 1948
Brahea edulis, Guadalupe Island. Photo by Reid Moran, 1948.

Expedition 2000 to Isla Guadalupe
A Binational Multidisciplinary Expedition

Botanical Exploration and Survey

One of the most important botanical endeavors is to explore and document the plants of areas not previously accessible by earlier scientists. For example, many of the more rugged and mountainous portions on the north end of Isla Guadalupe have had little or no botanical surveys conducted, and Islote Adentro on the south end of the main island has never been explored. However, with the use of the helicopter for transport, we will have the opportunity to gain access to these isolated areas and document their flora. According to Moran (1996) "the offshore islets are refugia for rare plants, including five never found on the main island," and since Islote Adentro has vegetation on top but has never been explored or collected due to sheer cliffs on all sides, there is a distinct possibility to encounter populations of rare plants or plant species now extinct on the main island. Furthermore, since approximately 22% of the plant taxa (including two monotypic genera) in the flora of Isla Guadalupe are endemic, there is a very high possibility that new plant taxa will be discovered, especially on Islote Adentro.

Moran states that "over 30 plant species are probably now extinct on the island and new weeds keep coming in as if to take their place." Therefore, another aspect of the botanical surveys will be to look for plant species now considered extinct on the island (e.g., Pogogyne tenuiflora, Castilleja guadalupensis, Satureja palmeri, etc.) and make observations on the status of various weedy plant species (Erodium moschatum, Hordeum murinum, Sonchus oleraceus, etc.).

Botanical observations (plant species' abundance, distribution, goat-related impacts, etc.) and collected plant specimens from this exploration of Isla Guadalupe will not only provide science with basic natural history information integral for establishing criteria used to evaluate biodiversity and conservation measures, but they will also promote the growth of regional herbarium collections, especially in Mexico; and furthermore, promote future binational, cooperative, botanical research endeavors in the region.

Plant Collection Techniques

Plant material will be obtained from natural populations on Isla Guadalupe and adjacent islets by surveying the region either on foot or by helicopter transport. Standard plant collecting methods for herbarium documentation will be conducted at various localities. If the plant is small, the whole individual, roots and all, or even several of them will be collected to provide enough material. If large, a branch about 23 cm long, with leaves, flowers, and fruits, when possible, will be removed. The plant material will then be pressed in a standard herbarium press by placing the specimen in a folded newspaper sheet. The date and collection number will be written on the newspaper. The plant sample will be arranged so that all representative parts of it will show after pressing. The plant specimens will be separated with corrugated cardboard for air circulation. Blotters or paper towels may be used to absorb excess moisture in some plant specimens, when needed. The stack of specimens within newspapers separated by cardboard will be placed between wooden press end boards and strapped tightly to apply adequate pressure for flattening the specimens. The completed stack/press will be put where there is a good source of air circulation when in the field and into a herbarium drier upon return to the laboratory in order to promote fast drying and reduce the potential for fungal attack and growth on the specimens. When dry, the plant specimens will be removed from the press and placed into a freezer for five days in order to kill all possible insect pests.

Whenever possible, four "duplicate" samples for each collected specimen (per collection number) will be obtained from the field so that all collected material can be deposited in regional herbaria including: San Diego Natural History Museum (SD), Universidad Autónoma de Baja California (BCMEX), and the Centro de Investigaciones Biológicas del Noroeste (HCIB). The fourth sample will be sent to an expert on the plant taxon of the collected species for determination when collected material varies from the normal morphology and its identification is questionable, or when material is difficult to identify.

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Ornithology | Botany | Entomology | Herpetology

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