Endemics are organisms whose natural ranges are restricted to a particular geographic zone. The term is often confused with "indigenous", which simply means the species is native: existing in the specified region without having been planted there by modern humans. A species may be native, regardless of whether it is restricted; but all endemic species are native. The term "endemic" is relative to the area you chose to define. You can say that all known species are endemic to the world. Another suite of species are endemic to the Western States. This book focuses on endemics to the California biological region. 

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This may seem straightforward enough, but natural ranges can change. In this book, a "natural range" means the typical, native extent a species occurs in, or has occurred in during the modern epoch. The importance of endemism is not necessarily whether or not an organism can survive outside of the California biological region, but why it has had an affinity for it over thousands or millions of years. Therefore, I consider an organism endemic even if it may wander irregularly outside of the region (marine fishes during El Nino, for example); or if, in the case of the coast silktassle (Garrya elliptica) and California quail (Callipepla californica), it thrives in other parts of the world where humans transplanted them.  

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Endemism may be further specified to a particular habitat. Serpentine endemics are plants which occur only in serpentinite soils. Likewise plants and animals found only in Western Vernal pools, are "vernal pool endemics". For that matter, particular habitats (i.e. western vernal pools and California chaparral), minerals, and even languages can be described using this term.

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Broad endemics are those found widely within a region, or even just slightly beyond its borders. The desert candle (Caulanthus inflatus) is a broad endemic because it is found in both desert and coast ranges while still being limited to the state of California. Dozens of plants and animals' ranges form a near-exact footprint of the California Floristic Province. A butterfly, the California sister (Adelpha californica), has a range that closely matches this outline; as does the California bay laurel (Umbellularia californica); and the wrentit (Chamaea fasciatata).  

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More often, species are narrow endemics. The black toad (Anaxyrus exsul), for example, is found only within marshes of Deep Springs Valley. The Carpenteria (Carpenteria californica) is known only from the foothills outside Fresno. The alpine chipmunk (Tamias alpinus) is a narrow endemic to high elevation habitats of the Sierra Nevada.

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True Endemics of the region are species whose entire worldwide range exists 100% within a defined area. Within the the state of California, the yellow-billed magpie (Pica nuttalli) and the genus of web-toed salamanders (Hydromantes) fit this description. The coastal redwood (Sequoia sempervirens) and California legless lizard (Anniella pulchra) are among thousands of others that are truly endemic to the California Floristic Province. One can further define true endemism within the various ecological zones of California. The island fox (Urocyon littoralis), island scrub jay (Aphelocoma insularis), and island monkeyflower (Mimulus flemingii) are endemic to the Channel Islands.

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Near Endemics in this book are defined as taxa whose ranges are 80%-99% confined to the region. The oak titmouse (Baeolophus inornatus), which has a small population at the southern tip of Baja California is a classic example. Sugar pine (Pinus lambertiana) and incense cedar (Calodecrus decurrens) are near-endemics because their ranges continue into the Cascades of central Oregon. I have not strictly measured the areas of all the species included in this book to determine whether they fall within this percentage; it is a rough estimate. Near-endemic genera are those in which 80-99% of the species within it are endemic. The genus Arctostaphylos (the manzanitas), Batrachoseps (the slender salamanders), and Timema (the short-horned walking sticks) are prime examples. 

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Semi-Endemic organisms have worldwide ranges which are 50-80% restricted to an area. The term is adapted from the California Bird Species of Special Concern Bird Responsibility List, which emphasizes conservation implications for species found mostly within the state. In this book, I use it mostly with bird and mammal species, which are less easily defined as endemics due to their generally wider ranges and ability to migrate. Semi-endemism is certainly a weaker way to describe the ecological uniqueness of an area, but is a still an indication of its value in diversity, in addition to conservation value. This is particularly true in examining species which are endemic within a sub-ecoregion that straddles the boundaries of the California Biological Area as we've defined it. The North Coastal Ranges (home to the hermit warbler, Setophaga occidentalis); the combination of California and Baja (California towhee, Melozone crissalis; among others); and the full extent of the California Current (home to the Brandt's cormorant, Phalacorcorax penicillatus and western gull, Larus occidentalis) are examples. Semi-endemic genera are quite common among California plants, notably Ceanothus; and animals including the genus Tamias, the chipmunks.

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Seasonal Endemics are species whose entire worldwide population exists within a region during a portion of the year. A breeding endemic, such as the Lawrence's goldfinch (Spinus lawrencei), may winter widely outside of California, but only summers within the province. Wintering endemics are rarer, but examples exist, particularly among subspecies of birds. The Aleutian cackling goose (Branta hutchinsii leucopareia) is found exclusively in the region prior to their departure north to breed.

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Paleoendemics are a California specialty. These are organisms that may have occurred widely during a different age, but naturally died out in all but a small portion of their former range. Both species of redwood, the California condor (Gymnogyps californianus), and the island ironwood (Lyonothamnus floribundus) are well-known examples. Most paloendemics are considered "living fossils", species that have not changed much since previous geologic times. 

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Conversely, neoendemics are species that evolved recently within a region. The Nuttall's woodpecker (Picoides nuttallii), split from the ladder-backed woodpecker within the last ice age, and has an obvious similarity to it. Most species of farewell-to-spring (Clarkia spp.) represent species that have diverged as California's geology has become more complex. Because the region is relatively young, geologically speaking, many of our neoendemics look very similar to each other.

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Former Endemic species are species that are traditionally endemic, but have recently expanded their ranges of their own volition (though often in response to human involvement). Anna's hummingbird (Calypte anna) used to breed exclusively within Southern California and northern Baja; but has expanded into Arizona and British Columbia, in part because of food associated with landscaping.

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Endangered Species

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"Endangered Species" is a broad term that is used to define organisms that are in danger of becoming extinct. There are many ways of interpreting this, based on different stakeholders, governing agencies, or research organizations.

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The Federal Endangered Species Act of 1973 (FESA) was set in place to prevent extinction of imperiled organisms within the United States through management efforts which either remove threats, prevent further threats, or even actively attempt to repopulate species. FESA is administered by the United States Fish & Wildlife Service (USFWS), which handles terrestrial and aquatic species; and the National Marine Fisheries Service (NMFS) which manages marine organisms. Species may be placed on the an Endangered Species List These agencies through these agencies, based on the following criteria:

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• Federally Endangered - a species is in danger of extinction throughout all or a significant portion of its range. 

• Federally Threatened - a species is likely to become endangered within the foreseeable future. 

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The California Endangered Species Act (CESA) states that all native species of fishes, amphibians, reptiles, birds, mammals, invertebrates, and plants, and their habitats, threatened with extinction and those experiencing a significant decline which, if not halted, would lead to a threatened or endangered designation, will be protected or preserved. 

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CESA is governed by the California Department of Fish and Wildlife (CDFW), and also lists species as:

 

• State Endangered - a species in danger of extinction within California

• State Threatened - a species likely to become endangered within the foreseeable future within California

• State Rare - a vintage term used for species which were considered "threatened" before that term was introduced. Some species still bear this title.

• State Fully Protected - species initially identified as requiring additional protection to those animals that were rare or faced possible extinction. Most of the species on these lists have subsequently been listed under the California and/or Federal Endangered Species Acts; the exceptions are white-tailed kite, golden eagle, trumpeter swan, northern elephant seal, and ring-tailed cat. 

• Species of Special Concern - Vertebrate species with declining population levels, limited ranges, and/or continuing threats have made them vulnerable to extinction.

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The International Union for Conservation of Nature (IUCN) has no legal sway in the United States or Mexico, but uses a standardized rubric for determining endangered species across the world. Therefore, when comparing the number of endangered species within our region to other world hotspots, we will use the IUCN's version of the endangered species list, the IUCN Red Book.

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• Extinct (EX) – No known individuals remaining.

• Extinct in the wild (EW) – Known only to survive in captivity, or as a naturalized population outside its historic range.

• Critically endangered (CR) – Extremely high risk of extinction in the wild.

• Endangered (EN) – High risk of extinction in the wild.

• Vulnerable (VU) – High risk of endangerment in the wild.

• Near threatened (NT) – Likely to become endangered in the near future.

• Least concern (LC) – Lowest risk. Does not qualify for a more at-risk category. Widespread and abundant taxa are included in this category.

• Data deficient (DD) – Not enough data to make an assessment of its risk of extinction.

• Not evaluated (NE) – Has not yet been evaluated against the criteria.

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