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Crossosoma 34(2), Fall-Winter 2008 
of terricolous lichen species, for instance, possibly Aspicilia glaucopsina (Nyl. 
ex Hasse) Hue, Aspicilia praecrenata (Nyl. ex Hasse) Hue, Texosporium sancti- 
jacobi (Tuck.) Nadv. exTibell & Hofsten as well as the newly-described Caloplaca 
obamae K. Knudsen from Santa Rosa Island (Knudsen 2009). 
With the removal of the sheep over forty years ago, some of the native biota 
on San Miguel Island is recovering. For instance, according to Stephen McCabe 
(pers. comm.) when Reid Moran visited San Miguel Island in the 1950s, he saw 
no Dudleya. Now Dudleya greenei are almost everywhere around the base of San 
Miguel Hill and I saw populations scattered all over the areas I surveyed. With 
the resurgence of Dudleya species on San Miguel Island there is evidence of the 
renewed development of biological soil crusts consisting mainly of lichens and 
cyanobacteria. But the diversity of lichens in biological crusts appears to be low 
compared to those in undisturbed areas. 
For example, Cladonia nashii is a terricolous lichen described from Santa Rosa 
Island where it occurs across the island and pioneers road cuts and covers soil 
areas where it cannot be trampled by the remaining feral deer and elk. It has wide 
ecological amplitude and can even be found as far inland in California as the west 
slope of the San Jacinto Mountains. It is endemic to California from San Simeon 
to Baja. 
During my survey I found a single population of Cladonia nashii consisting 
of five small individual patches on a steep slope of deep soil in upper Willow 
Canyon. No other Cladonia species were found. At least one other Cladonia 
species occurred on the San Miguel Island in the recent past, voucherd by a single 
Nash collection from Green Mountain that was too scant for positive ID to species 
(ASU). Based on work at coastal sites in southern California such as Torrey Pines 
and Point Loma and a continuing studies of Santa Rosa Island and West Anacapa 
Island, there should be at least four to five species of Cladonia on San Miguel 
Island, including the California endemics Cladonia hammeri Ahti and Cladonia 
maritima K. Knudsen & Lendemer (Knudsen & Lendemer 2009). 
I have no doubt that the terricolous lichens will continue to recover but I believe 
that they will be less diverse then they were prior to grazing. 
These rather depressing conclusions should not blind us to the beauty of San 
Miguel’s remaining lichens. Or that the island we see now will be very different in 
a hundred years after we are dead and buried thanks to the policies of the National 
Park Service to protect and conserve the island’s natural resources. 
