Population assessment and conservation strategies for the Critically Endangered lichen Sulcaria isidiifera

Le résumé fourni par la source

The epiphytic lichen Sulcaria isidiifera is a critically imperiled species endemic to the coast of central California, USA, where it occupies just a few patches of old-growth maritime chaparral habitat. S. isidiifera has experienced major habitat loss due to urban development, while facing ongoing threats from wildfires, land conversion, and climate change. In 2019, S. isidiifera was listed on the IUCN Red List. The Red List assessment recommended that the species be monitored to track abundance, reintroduced where extirpated, and listed as an endangered species in the USA. Our study aimed to follow up on recommended conservation actions by characterizing occupied habitat, obtaining comprehensive abundance data, and performing a translocation experiment. Population data collected during our study resulted in estimates of 13841-25064 individuals growing on 3588-7772 host shrubs distributed across a range of 24 km2. S. isidiifera was more abundant in areas exhibiting greater winter-to-summer swings in relative humidity. The foliose lichen Leucodermia leucomelos was identified as an indicator species for S. isidiifera. To determine whether the IUCN recommendation of reintroducing S. isidiifera to previously occupied habitat is feasible, we translocated individuals of S. isidiifera to nearby putative suitable habitat and monitored their health using chlorophyll fluorescence. After 3.5 yr, we report 92% survival of translocated individuals with no notable negative impacts on their health. The population size and restricted range of this species indicate that management activities like translocation, and Endangered Species Act listing are warranted to conserve S. isidiifera.

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