Hello CactiGuide! I used to be very active here but embarked on a graduate program in environmental life sciences with a focus on cactus biology, ecology, conservation and speciation at Arizona State and I've been swamped with work from that endeavor. It's been great but very challenging. I have been somewhat surprised by the intensely quantitative methods used in ecology now, the incorporation of sophisticated mathematical models, statistical analysis, geospatial analysis and Bayesian inference. I've worked with tons of different computer software packages now, such as R for stats, ArcGIS for geospatial mapping and analysis of species distributions, PAUP for phylogenetic analysis of the Mammilloid Clade (which is broadly the study group I decided on, specifically Cochemiea), etc., etc. I'm 54 and graduated from undergrad in 1985 and *so much* has changed in biology along computational and quantitative lines. Very interesting and very challenging.
However, my first love is field botany and I chose the Pacific Islands in Bahía Magdalena as my study site to try to get a better handle on the incredible endemism in cacti and succulents there. In the region generally, including on the peninsula, there's Stenocereus eruca, Echinocereus barthelowanus, Cylindropuntia ciribe, Lophocereus gatesii, Ferocactus santa-maria, Opuntia pycnantha, Cylindropuntia santamaria, Agave margaritae, Cochemiea halei that are all regionally restricted endemics, some much more restricted than others.
I have focused on the Cochemiea group which phylogenetically seems to fit neatly in the Mammilloid Clade that also includes Mammillaria schumannii, M. armillata, M. fraileana and a variety of other Baja endemics. It is a strange group within Mammillaria and interesting. In particular I'm developing microsatellite markers for Cochemiea that will undoubtedly be useful for population genetics studies in Baja Mammillaria in general, which in turn might help clarify more the phylogeny of this huge genus.
Cochemiea halei is my particular study species. It grows almost entirely on Islas Magdalena and Santa Margarita in Bahia Magdalena, with a very small peninsular population near Puerto San Carlos. I am working on the demography, population structure and vital rates, population diversity and genetic population structure of the species across its entire known range, which is only about 52 km by 40 km. The species occurs in highly fragmented patches of dense colonization that alternate with near total absence or very sparse distribution. Dispersal seems very very slow indeed and plants, once established, seem long lived. Recruitment of new plants seems very low, however.
Here's a public link to a Facebook photo album of my last trip down the Baja peninsula in December. The Bahia Magdalena pics start about 20 pics in or so. Hope you enjoy.
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Peter Breslin
