most important threats to the populations. Nonnative species Nonnative species serve as competition and habitat modifiers that can limit cypress success. Acacia dealbata and Genista monspessulana impact Santa Cruz populations by blocking sunlight and by competing for soil space to germinate. More nonnative invasions are possible in the future due to the cypress’ closeness to residential areas. The foot travel and human activities in these areas can bring more invasive species. Genetic Introgression In 2016, the conservation status of the Santa Cruz cypress was reduced to threatened. The cited reasoning was a decrease in threats against their habitat. However, a lengthy section of the 2016 federal report titled "Genetic introgression" (also known as introgressive hybridization) explains how the integrity of this species is also threatened by nearby horticultural plantings of a sister species, Monterey cypress, whose historically native range is nearby: on the opposite side of Monterey Bay. Hybridization is known to occur between the two endemics — as well as with a widely planted sister species native to Arizona: Arizona cypress. The ease of hybridization of cypress species in the American southwest has fostered a parallel history of taxonomic disagreements of where genus and species distinctions should apply. It thus provides a case study of neoendemism in conifers. As well, it illustrates an element of ongoing human impact — wind-dispersed pollen contamination from horticultural plantings — that cannot easily be corrected to meet conservation goals. Additional threats Another major human-derived threat to the species is climate change. Rising temperatures may push populations northwards, as well as further alter the fire regime. The species is also damaged by vandalism and unauthorized recreational activities. Actions like carving into bark damage the trees, encouraging infections and disease. In the past, the conversion of habitat into agricultural lands and residential areas was a major threat. But as populations became protected and preserved, the threat has since decreased. Current conservation efforts The U.S. Fish and Wildlife Service released the first recovery plan for the Santa Cruz cypress in 1998. In 2009, the updated recovery plan recommended the reclassification of the species to threatened when protection for all five populations and their habitat is secured. Downlisting from endangered to threatened was authorized in the 2016 update of the recovery plan. The listed primary threats to control are logging, agricultural conversion, and development. The U.S. Fish and Wildlife Service lists all 356 acres of habitat as