Abstract Detail


Calloway, Stephanie [1], Guilliams, C. Matt [2], Ritter, Matt [3], Hasenstab-Lehman, Kristen [4], Yost, Jenn [5].

Saving the rare northern island mallow on Anacapa Island.

The northern island mallow, Malva assurgentiflora subsp. assurgentiflora, is a rare shrub endemic to Anacapa and San Miguel Islands – two of California’s Channel Islands located off the coast of southern California. Grazing by introduced herbivores drastically degraded Channel Island ecosystems. While introduced herbivores were removed from seven of the eight Channel Islands nearly two decades ago, many species have failed to recover, including Malva. On Anacapa Island, naturally occurring Malva are presumed extirpated. Fortunately, prior to extirpation, seeds were collected from the last remaining plants and used to create a new population on East Anacapa Island, where ~1,000 individuals were planted in a restoration site managed by the National Park Service. In the years following restoration, however, the new population has failed to produce recruits. This alarming lack of recruitment puts Malva at risk of future declines. The overall goal of this research was to learn more about Malva’s recruitment dynamics on Anacapa Island and the potential impact of the Anacapa deer mouse – an endemic subspecies, and a known seed predator of Malva.
In 2020, we began research on Anacapa Island to track the fate of Malva fruits, seeds, and seedlings during several early life history stages (pre-dispersal, post-dispersal, germination, seedling emergence, and seedling survival and establishment) under deer mouse included and excluded conditions. Deer mice removed ~70% of non-dispersed fruits from reproductive Malva before they were able to mature to viable fruits, compared to treatments that excluded deer mice from fruits, where 100% of fruits matured to viable fruits. Deer mice removed ~50% of dispersed fruits during spring trials compare to 100% in fall trials as deer mouse densities increased. Germination only occurred in treatments where deer mice were completely excluded from sewed seeds. However, ~95% of seedlings died due to lack of water, regardless of deer mouse exposure, showing that water availability may be more important for seedling survival than deer mouse predation.

1 - California Polytechnic State University, San Luis Obispo, Biology, 1 Grand Ave, San Luis Obispo, CA, 93407, United States
2 - Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA, 93105, United States
3 - Cal Poly, SLO, Biology Department, 1 Grand Ave., San Luis Obispo, CA, 93407, United States
4 - Santa Barbara Botanic Garden, 1212 MIssion Canyon Road, Santa Barabra, CA, 93105, United States
5 - Cal Poly, Biology, 1 Grand Ave, San Luis Obispo, CA, 93407, United States

rare plants
Island Ecology
Peromyscus maniculatus subsp. anacapae
Seed Predation
Endemic Species.

Presentation Type: Oral Paper
Number: EC02004
Abstract ID:193
Candidate for Awards:Ecological Section Best Graduate Student Paper

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