Natural World

Natural Features & Ecosystems

The significance of Channel Islands National Park stems from the islands' remote, isolated position at the confluence of two major ocean currents, a region of persistent oceanic upwelling, and the border of two tectonic plates. The park contains examples of two biogeographical provinces in the ocean, the Oregonian and the Californian, and a dynamic transition zone between them. In a remarkably small area, the park harbors the biologic diversity of nearly 1,000 miles of the West Coast of North America. In addition to this diversity, park waters are also exceptionally productive. Swirling around the islands, cool, nutrient-rich oceanic waters rise into abundant sunlight and mix with warm coastal waters, accelerating photosynthesis and growth rates of myriad forms of sea life from microscopic plankton to blue whales.

The park preserves some of the finest remnants of the coastal Mediterranean-type ecosystem in America. The most endangered in the world, this type of ecosystem is found in only five places. The unique suite of plants and animals that have colonized the islands and their isolation over eons has resulted in the evolution of many endemic species and subspecies. The park also harbors a prolific paleontological record; archeological resources that record nearly 13,000 years of continuous human occupation; and historical features that represent ranching, fishing, hunting, navigation, and other endeavors from a wide variety of cultures.

The Channel Islands National Park provides the public with unparalleled opportunities for solitude, tranquility, wildlife viewing, and appreciation of natural history, outdoor recreation, and education.

Fire Regime

There is relatively less fire on the Channel Islands than on the mainland because ignition sources are much less common there and the foggy maritime climate generally limits fire spread. Although similar plant communities on the mainland experience regular fire, fire on the islands would have been much less frequent during the evolutionary history of island plant communities until evidence of human occupation on Channel Islands that extends back some 13,000 years. Several island taxa have relaxed fire-adapted traits such as serotiny and seed germination characteristics.

Sediment cores from Santa Cruz and Santa Rosa Island were used to evaluate historic fire occurrence on the islands. Cores from an upland site on Santa Rosa (Soledad Pond) showed that fire occurred throughout the 12,000 years of the sediment record with large scale, major fire events occurring with a minimum frequency of between 1 event/1000 years and 4.5 events/1000 years. A second coastal site on Santa Rosa Island (Abalone Rocks) yielded estimates of large scale fire events ranging from 5.5 to more than 9 events/1000years. Records from both Santa Cruz and Santa Rosa show that fire frequencies increased over the last 5000 years and reached their peaks during the historic period, approximately the last 200 years. Although it seems logical that the increase in fire activity could be attributed to Native American burning, the data could not distinguish between climatic or anthropogenic causes. Whatever the source of the fires represented in the charcoal record was, the historic fire return intervals on the Channel Islands are significantly longer than estimates of modern fire return intervals in mainland shrubland communities.

Weather

Channel Islands National Park has a Mediterranean-type climate. This climate type is characterized by cool, wet winters with average annual rainfall of 8-40” and hot, dry summers. These climate regions occur in only five locations throughout the world including parts of California, along the Mediterranean Sea, central Chile, parts of southwestern Western and South Australia, and the southwestern Cape region of South Africa.

On the Channel Islands the climate is moderated by the marine influence with the result that summers are milder, there is generally higher humidity, and there is more frequent nocturnal fog compared to the mainland. In the Köppen system of climate classification this is a cool Mediterranean climate (Csb) or a Mediterranean Dry Summer Subtropical climate type, with a cool summer regime.

There are currently five Remote Automated Weather Stations (RAWS) stations at Channel Islands National Park. Current and historic data from these stations are available at the Western Regional Climate Center (WRCC) website at http://www.wrcc.dri.edu/channel_isl/.  Historic data from San Miguel Island are also located at the WRCC website.

Unfortunately data collected from these stations has been irregular so that the historic weather analysis provided below is derived from other published records of Channel Islands climate data.

Temperature

December-March are the coolest months and July-October the hottest months in the Channel Islands. The average mean temperature in January ranges from 53-59 degrees F; summers are a little warmer with an average mean temperature in July that ranges from 62-70 degrees F. Both winter and summer temperature extremes are moderated by the moist ocean air with generally high nighttime humidities and frequent fog. Diurnal temperature differences are small with cool days and warm nights. The exception to the norm of relatively cool temperatures and high humidities occurs occasionally in the fall with Santa Ana wind conditions when temperatures dramatically increase and humidities decrease. As with rainfall, fog duration, and relative humidity there are significant variations in temperature between the islands. The Channel Islands are frost free for the most part. The one exception is the central valley of Santa Cruz Island where its inland location and surrounding high mountains create a microclimate more characteristic of a warm Mediterranean climate (Csa) such as that found on the mainland away from the immediate coast. This microclimate experiences freezing temperatures most years, higher average summer temperatures, and greater diurnal temperature variation.

Humidity

Relative humidity in and around the Channel Islands varies diurnally. At night and in the early morning relative humidity often reaches 100%. In the afternoon, readings on average reach around 60%.

Rainfall

On average, 95% of the rainfall in the Channel Islands occurs between November and April. January and February are the rainiest months (45% of average totals). Most rain comes from large storms that last for several days. The dry season generally extends from May-October. June, July and August are the driest months (1% of annual mean rainfall). Evaporation exceeds precipitation from April to November. Regional rainfall patterns are highly variable and unpredictable. Long periods may occur between storms in a single season, and enormous variation exists in yearly rainfall totals. Extended multi-year droughts punctuated by moderate to extremely wet years are not uncommon. Rainfall patterns also vary geographically within the Channel Islands National Park. Annual rainfall is about 14” per year but depending upon the topographical features of a particular location, rainfall on the islands might range from less than 10 inches to more than 20 inches annually.

Fog

Fog is a common weather feature, especially at San Miguel and Santa Rosa Islands. Fog is most common in spring and summer, and west of the Santa Cruz Channel. The marine layer fog flows down the coast with the prevailing NW wind, and bends around Point Conception, usually blanketing San Miguel and Santa Rosa, and often the western portion of Santa Cruz Island. Fog frequently is thicker and lingers longer into the day offshore than along the mainland coast. Preliminary data from Santa Cruz Island suggests that geographic variation in the presence and duration of the fog layer has a profound influence on the temperature and humidity regimes.

Wind

Throughout the year, winds are primarily from the west-northwest, tending to increase throughout daylight hours and becoming east-northeasterly at night. Periodically, southern California experiences extreme foehn-type winds locally called Santa Ana winds. These high velocity winds are often associated with high temperatures and extremely low humidities. They have been identified as the primary driver of the wildfire regime in southern and central California shrublands. Santa Ana winds result from a regional, large scale weather pattern caused by the atmospheric pressure differential between a Great Basin high-pressure cell and a Pacific Coast trough of low pressure. On the mainland these winds average 20-25 mph and maximum gusts over 100 mph have been recorded (http://www.nasm.si.edu/exhibitions/lae/html/what_new.htm). The Channel Islands experience Santa Ana winds, but in the northern Channel Islands the intensity becomes less severe as the winds move from east to west. In contrast, the severity of the Santa Ana winds on Catalina Island seems to be as great as in the Los Angeles basin.

Although Santa Ana winds can occur in any month, they predominate from September to December. In the Santa Monica Mountains the occurrence of major fires coincides with this peak of Santa Ana wind activity when vegetation is dry and temperatures high. A second small peak of Santa Ana wind activity occurs in March, but this is usually a time of high live fuel high moisture and does not create the severe fire conditions that occur during the fall Santa Ana winds.

In addition to the regional Santa Ana winds, the Santa Barbara area experiences another type of local wind event that is associated with severe wildfires. These are downslope winds that occur primarily in the late afternoon to early evening known as “Sundowners”. These winds are heated adiabatically as they descend downslope from the north on the lee side of the east-west trending Santa Ynez Mountains, creating a temperature increase much higher than the seasonal norms. Sundowners have been associated with numerous severe wildfires in the Santa Barbara area, the most recent of which was the June, 1990 Painted Cave Fire when 640 structures burned. Unlike Santa Ana winds, Sundowners are more common in the summer (June, July, September) than the fall (September, October, November, December). Sundowners vary in duration and intensity. Light sundowners (Category 1) cause irregular increases in temperature and light offshore breezes. Strong sundowners (Category 2) can occur 2-3 times/ year with a sharp increase in temperature and local gale force winds. Severe sundowners occur every 5-10 years and develop hot damaging winds along the south side of the Santa Ynez Mountains and the adjacent littoral (Category 3). There are anecdotal reports that Category 3 Sundowner events can push across to the Channel Islands, however a Sundowner event monitored on June 30, 1996 did not reach either Santa Rosa or Santa Cruz islands.  Because of the infrequency of the most severe Sundowners, they probably play a less significant role in fire weather on the northern Channel Islands than do Santa Ana winds.

Environmental Factors

Natural areas, such as Channel Islands National Park, play an important role in indicating when critical changes are happening on the earth, our life support system. Parks can play the role of "the canary in the mine." Just as the miner's canary alerted mine workers to poison gases in a shaft, natural areas can alert us to biological, chemical, and environmental changes that will affect our quality of life and the survival of species.

The Channel Islands played a role in two events in 1969 that galvanized our nation to take seriously the growing warning signs of our deteriorating environment. In January 1969, an environmental disaster occurred in the Santa Barbara Channel. An offshore oil platform suffered a blowout. 200,000 gallons of crude oil escaped into the ocean over a period of eleven days. The oil created an 800-square- mile slick that impacted all of the northern Channel Islands and nearby mainland beaches. Thousands of seabirds and marine mammals died.

At the same time, scientists were becoming aware of a serious decline in the breeding success of California brown pelicans. Adult brown pelicans appeared to still be numerous, providing a deceptive façade that things were all right. However, when the scientists looked more closely, they realized with horror that the pelicans were unable to nest successfully because the eggshells were too thin to withstand incubation and thus were crushed in the nest. For several years, the pelicans suffered nearly total reproductive failure. In 1970, only one chick was successfully raised on Anacapa Island, an island that had historically been the largest breeding colony for California brown pelicans on the west coast of the U.S.

The cause of the failed pelican breeding was DDT, an organochlorine pesticide. In the late 1960s and early 1970s the mean eggshell thickness was found to be approximately 50% thinner than normal. High levels of DDT residues were correlated with the eggshell thinning--the higher the DDT levels the thinner the eggshells. Later analysis of museum eggshells collected before 1943 and the notes of biologists showed that the eggshells of California brown pelicans were substantially thinner by 1962. Also, a long-term decline of brown pelicans had started along the California coast as early as the mid-1950s. DDT similary affected bald eagles and peregrine falcons. However, because there was no standardized biological monitoring of pelicans (or any other wildlife), the problem wasn't identified until the populations had nearly collapsed.

Pollutants have hit other species hard on the Channel Islands. Bald eagles were once an important component of the island ecosystem. It is estimated that at least twenty nesting pairs of bald eagles occurred on the park islands in the early 1900s. Hunting, egg collection, and DDT all took their toll and resulted in the total elimination of bald eagles by the 1950s.

Fortunately, the American public and government reacted strongly to the loss of wildlife and the growing pollution of the environment. Many consider the publicity surrounding the Santa Barbara oil spill and the fate of the California brown pelican a major impetus to the environmental movement. Just one year later, in the spring of 1970, Earth Day was born.

Rare Plants

Federally listed plants of Channel Islands National Park

The following is the list of 14 threatened or endangered plants found in Channel Islands National Park. A strict legal process is needed in order for a plant or animal species to be listed. Information about the Endangered Species Act and the listing process can be found at the U.S. Fish & Wildlife Service website at the U.S. Fish & WIldlife Service website at http://www.fws.gov/endangered/wildlife.html.

Plants

Channel Islands National Park supports a diverse terrestrial flora, including many rare, relict, and endemic species, as well as many nonnative species. Numerous plants are rare on the islands but have a wider distribution on the mainland. On the other hand, due to environmental conditions and isolation from the mainland, many of the plants that are native on the California mainland do not grow here. A total of about 790 plant taxa, including species, subspecies, varieties, and forms, have been identified in the park, of which about 578 are native and 205 are nonnative.

Each island supports a unique assemblage of vegetative communities, which differ due to climate, microhabitats, topography, geology, soils, plant colonization history, isolation, and land use history. Many of the islands' native vegetative communities have been greatly altered by people and the introduction of nonnative species and are in various stages of recovery. The major vegetative community types on the islands include coastal dune, coastal bluff, coastal sage scrub, grasslands, chaparral, island oak woodlands, mixed hardwood woodlands, pine stands, and riparian areas. Currently, the most extensive vegetation communities on the islands are grassland and coastal sage scrub with significant areas of chaparral on Santa Cruz Island, and to a lesser degree, on Santa Rosa Island. Various phases of coastal bluff scrub constitute the next largest category. Mixed broadleaf woodland stands, oak woodlands, and pine stands are scattered throughout on sheltered slopes and canyons, or on ridges exposed to frequent moist fogs. Smaller but no less significant vegetation communities include coastal dune, baccharis scrub, caliche scrub, and wetlands.

Animals

A variety of organisms can be found on and around the Channel Islands, from top predators like bald eagles and sharks, to intertidal residents such as seastars and barnaces, to the tiniest parasites living on other animals and plants. For this page we have organized the information into Birds, Marine Animals, and Terrestrial Animals, although many animals utilize resources from both the ocean and the land.

Because of their isolation and remote nature, the Channel Islands support fewer native animal species than similar habitats on the mainland. Species that reached the islands were aerial, such as birds and bats, or rafted across the water on debris and other material. Over time some vertebrate species evolved into distinct subspecies on the islands. For example, the deer mouse and island fox are recognized as distinct subspecies on each of the islands they occur. A total of 23 endemic terrestrial animals have been identified in the park, including 11 land birds, that are Channel Island subspecies or races.

Loggerhead Shrike

Common Name
Loggerhead Shrike

Scientific Name
Lanius ludovicianus anthonyi

Conservation Status
Breeding population is unknown. Due to lack of research on demographics of this subspecies, population trends are uncertain.

Habitat
Loggerhead shrikes utilize ecotones, grasslands, and other open habitats with scattered shrubs and trees, suitable perches, bare ground, and low or sparse herbaceous cover as primary habitat and breeding territories.

Natural History
The loggerhead shrike is an endemic subspecies of the California Northern Channel Islands. They are predatory songbirds with strong, hooked bills they use to kill and dismember prey, which include insects or small vertebrates, birds, and small reptiles.

Additional Information
An in-depth look at the status of the loggerhead shrike can be found at islandloggerheadshrike.org.

Xantus's Murrelet

Common Name
Xantus's Murrelet

Scientific Name
Synthliboramphus hypoleucus

Conservation Status
After feral cats were removed from Santa Barbara Island in 1978, numbers of this species increased from zero in 1939 to approximately 1,500 in 1992. Programs are underway at many of the current or former nesting islands to remove feral cats and other introduced predators and to educate island residents about the importance of predator-free islands for the survival of these and other colonial nesting seabirds.

Habitat
Nests on steep sea-slopes, canyons and cliffs with a sparse cover of herbaceous and shrubby plants on Anacapa and Santa Barbara Islands.

Natural History
As a member of the auk family that usually favors norhtern waters, the Xantus's Murrelet is found mostly off Baja and southern California in pairs or faimily groups, but not flocks. It nests on offshore islands and is rarely seen from the mainland.

Brown Pelican

Pelecanus occidentalis Pelecanus occidentalis californicus

Pelicans breed in nesting colonies on islands without mammalian predators and permanent human habitation. They typically build a nest on the ground and on low shrubs. On West Anacapa and Santa Barbara pelicans generally nest on inaccessible slopes, canyons, and high bluff tops and edges. Brown pelican are asynchronous nesters. The nesting season can extend from January through October. Normal clutch size is three eggs. The peak of egg laying is usually March or April; however, eggs are often laid through June. Pelican breeding success is largely determined by the availability of their primary prey items, northern anchovies (Engraulis mordax) and Pacific sardines (Sagax sarinops), which during the breeding season comprises nearly their whole diet.

In the 1970s the park's colonies almost disappeared due to eggshell thinning and consequent reproductive failure. Pelicans are extremely sensitive to bioaccumulation of the organochlorine contaminants in the marine environment, particularly DDT and its metabolites, and polychlorinated biphenyls (PCBs). DDT has been shown to alter the birds' calcium metabolism, resulting in egg-shell thinning.

The park's breeding populations have steadily increased since 1980, although they are now believed to be fairly stable. An estimated 6,000 pairs were found on West Anacapa in 2002, although this was an unusually high number. Between 1979 and 2001 the colony produced a mean of about 3,600 nests per year. On Santa Barbara there are an estimated 1,200 pairs. Pelicans were not known to nest on Santa Barbara in recent times until 1980; the first significant nesting occurred in 1985. From 1985 to 2001 the colony produced a mean ofabout 770 nests per year. Starting in 2000 the pelicans started moving their nesting area around on the island. Santa Barbara is unusual in that it is the only island known along the Pacific Coast where both nesting pelicans and humans cohabit.

California brown pelicans still face several threats. Breeding populations and productivity vary dramatically yearly, depending on climatic and oceanographic conditions, which affect food availability and abundance. Other threats include disturbance of roosting and nesting birds, oil spills and other pollution, entanglement with hooks and fishing lines, and disease outbreaks resulting from overcrowding at winter roosts.

Nesting and roosting birds are very sensi­tive to human disturbance. Pelicans are affected by ancillary fishing activities, including the presence of vessels, noise, and lights, near roosting and breeding areas. Increased light levels are known to alter the behavior of diurnal species such as pelicans, leading to nest abandonment and increased egg and chick mortality. In 1999 large increases in nighttime squid fishing activity on park waters probably affected nesting pelicans — higher than average rates of nest abandonment and chick mortality were recorded and could not be explained by other environmental factors.

Activities such as sea kayaking and recreational boating also can disrupt nesting and significantly lower breeding success, as well as affect distribution patterns of roosting pelicans in both breeding and nonbreeding seasons. It has been suggested that people not be allowed within 328 feet (100 meters) of nesting or roosting pelicans to prevent disturbance due to the presence of people.

In the past human activities affected pelicans in the Channel Islands. Boaters and kayakers often approached within meters of the park's main islands and rocks that supported roosting and nesting pelicans. Maintenance of the U.S. Coast Guard lighthouse and foghorn also may have affected roosting pelicans. Scientists conducting seabird research occasionally flush small numbers of roosting birds. And research by the National Marine Fisheries Service at Point Bennett on San Miguel sometimes may disturb roosting birds. Some disturbance from recreational visitors in boats may still occur, although visitor access restrictions are believed to be largely limiting this potential impact.

Park visitor access is restricted on West Anacapa. A no-entry closure from January 1 through October 31 also keeps boats well offshore to protect fledglings in the vicinity of the nesting colony and provides a buffer zone to nesting pelicans. On Santa Barbara the pelican nesting area is closed to visitors and trails are closed when birds nest or show initial nesting behavior.

Bald Eagle

Common Name
Bald Eagle

Scientific Name
Haliaeetus leucocephalus

Conservation Status
Population declined seriously during the first two-thirds of the 20^th century. Even after eagles were fully protected their numbers continued to decline because of DDT and other pesticides. The numbers have increased steadily since the banning of DDT in the 1970s.

Habitat
The bald eagle explores coasts, rivers, large lakes, and mountainous open country.

Additional Information
Bald eagles were once permanent residents of Channel Islands National Park. Historical records indicate that bald eagles bred on all islands within the park, with at least two dozen nesting pairs over the 8 Channel Islands. Persecution by humans and the effects of organochlorine chemicals such as DDT eliminated breeding bald eagles on the Channel Islands by the mid-1950's.

Breeding bald eagles provided some ecosystem functions that are currently missing in the northern Channel Islands. For example, bald eagles were once the top marine aerial predator and probably fed upon a variety of seabirds and fish. Bald eagles are generally highly territorial, and in the past this behavior may have prevented golden eagles from colonizing the islands. The existence of breeding golden eagles on the islands at present may therefore be partially due to the absence of bald eagles.

In 2002, with funding from the Montrose Trustees Restoration Program, the park (in conjunction with partner, Institute for Wildlife Studies) began to introduce juvenile bald eagles to the northern Channel Islands. This was done using a technique called “hacking”. Birds of approximately 8 weeks of age were kept in one of two hack towers on Santa Cruz Island until they were ready to fly (at approximately 3 months of age). Sixty-one young bald eagles were introduced to the northern Channel Island between 2002 and 2006.

2006 marked the first successful bald eagle nest on the Channel Islands in over 50 years. In fact, there were two successful nests; both on Santa Cruz Island. One of the nests has a “web cam” and can be watched live during the nesting season.

Bald eagles were an important part of the island ecosystems. It is still unknown whether pollutant levels at the northern Channel Islands are sufficiently low to allow the eagles to consistently produce strong eggs and naturally hatch their young.

Snowy Plover

Common Name
Western Snowy Plover

Scientific Name
Charadrius alexandrinus

Conservation Status
The snowy plover is declining on the Pacific coast and considered threatened due to human disturbance of nesting.

Habitat
Snowy plovers look for flat, sandy beaches and dunes with little vegetation.

Additional Information
Western snowy plovers (Charadrius alexandrinus nivosus) breed from Washington State to Baja, California, and winter in coastal areas from southern Washington to Central America. Most western snowy plovers return to the same site in subsequent breeding seasons. They breed primarily above the mean high tide line. Their preferred coastal nesting habitats are sand spits, dune-backed beaches, unvegetated beach strands, open areas around estuaries, and beaches at river mouths. Their nests typically are shallow scrapes or depressions on the ground on flat, open areas with sandy or saline substrates, where vegetation and driftwood is sparse or absent. The nesting season extends from early March through September, with peak nesting occurring from mid-April through mid-August. Chicks reach fledging age about one month after hatching. Adults forage on invertebrates primarily along the water’s edge. On the Channel Islands they forage in the wet sand and amidst surf-cast kelp in the intertidal zone and in dry, sandy areas above the high tide. In winter, snowy plovers are found on many of the beaches used for nesting as well as on beaches where they do not nest, and on estuarine sand and mud flats.

The Pacific coast population of the western snowy plover was listed as threatened by the U.S. Fish and Wildlife Service on March 5, 1993. The population has declined due to many factors. Recreational and other human disturbance, loss of habitat to urban development, introduction of beachgrass (Ammophila spp.) and other nonnative species, and expanding predator populations have all contributed to a decline in active nesting areas and in the size of the breeding and wintering populations. It is estimated that about 2,000 snowy plovers may breed along the U.S. Pacific coast and that there are 157 current or historical snowy plover breeding or wintering locations along the U.S. Pacific coast.

Channel Islands National Park is one of the few locations in southern California that still supports breeding and wintering populations of western snowy plovers. In the 1990s Santa Rosa and San Miguel Islands had both breeding and wintering populations, but numbers have declined precipitously. A few birds also lived on The Nature Conservancy portion of Santa Cruz. On Santa Rosa the birds inhabited about 16 miles of coastline, while on San Miguel they were present on about 10 miles of shoreline. The Skunk Point area on Santa Rosa is an important nesting area and foraging area for juvenile and migrating plovers. Forty to fifty percent of the nests in this area have been found on rocky outcrops in the backdunes, about 490 to 980 feet (150 to 300 meters) from the shoreline.

Nesting snowy plovers are sensitive to disturbance. Activities that are detrimental to nesting birds include walking, jogging, unleashed dogs, and beachraking, among other uses. Recreationists can inadvertently step on eggs and chicks, destroying them. In addition, adults will stay away from a nest while people are present. Birds generally flush from nests when people come within 328 feet (100 meters). Separation of plover adults from their eggs or chicks may result in increasing mortality due to overheating in the sun, cold, blowing sand, or predators such as gulls or ravens. Trash left on a beach also may attract predators. People may cause broods of snowy plovers to run away from favored feeding areas.

To avoid disturbance of the birds, several of the beaches where snowy plovers currently nest are closed to recreational use. Specifically, all of the shoreline of San Miguel is closed to pubic landing or entry with the exception of Culyer Harbor. On Santa Rosa the coastline from and including Skunk Point to just north of East Point is closed to visitors, including landing or hiking, from March 1 to September 15. However, some people occasionally land or hike on these beaches during the nesting season. From South Point to Sandy Point and from Sandy Point to Carrington Point, camping also is permitted on the beaches only from September 1 through December 31. Camping and landing are prohibited year-round at the beaches around Sandy Point.

In the park, population numbers have declined on both Santa Rosa and San Miguel, concurrently with an overall decline in the breeding population in southern California. On Santa Rosa it is estimated that less than 30 breeding pairs were on the island in 2002 (most recent survey), down from 60 pairs in 1993. An estimated 200 birds still winter on the island’s beaches. On San Miguel, snowy plovers are sometimes sighted on beaches during the breeding season, but they are no longer known to breed on the island. An unknown number of birds also winter here.  

Different factors may be responsible for these declines on the islands. On San Miguel human disturbance of plovers has not been documented, nor have data been collected on the impacts of people on the Cuyler Harbor beach — the only beach visitors are permitted to use and once an important nesting area. It is believed that the decline in the breeding population on San Miguel may be due to a large increase in the number of northern elephant seals and California sea lions that have occupied snowy plover nesting habitat. This increase occurred simultan­eously with the western snowy plover decline.

Several factors may be responsible for the decline of western snowy plovers on Santa Rosa. In the past, ranch activities affected the plovers, including cattle and horses trampling nests and flushing birds from nests. Ungulate carcasses may have attracted predators such as ravens. Raven numbers are thought to be unnaturally high on Santa Rosa, which may be resulting in an increase in predation by ravens on plover eggs. Accumulations of trash also may have attracted predators. In the past, visitors, including hikers, surfers, and kayakers, affected the plovers at Skunk Point. But with the beach closures these impacts are happening less frequently on the beaches. High winds and predators are still a frequent cause of nest loss. In the past winds accounted for 28% to 34% of all nest losses, while predators (e.g., ravens, Santa Rosa Island spotted skunks) accounted for another 26% to 44% of losses. Both Santa Rosa and San Miguel have 20–30 knot winds on a regular basis through the plover nesting season, which can cause eggs to be sandblasted or blown out of the nest when the adult steps off the nest. It is also possible that ravens, which eat plover eggs and chicks, live on the island and may be more numerous than thought due to the presence of ungulate carcasses. In addition, increasing numbers of elephant seals hauling out on the south beaches of Santa Rosa could be reducing nesting habitat.

Marine Animals

An extremely rich and diverse community of marine mammals is found on and around the Channel Islands. Many species of pinnipeds (seals and sea lions) and cetaceans (whales and dolphins) either breed on the islands or feed in the productive waters of the Santa Barbara Channel.

Visitors to the islands often spot huge pods of common dolphins and smaller groups of Risso's dolphins, and occasionally see the more rare pacific white-sided and bottlenose dolphins. Dolphins feed on anchovies and other small fish, and follow schools of these prey as they move around the channel. Often groups of dolphins will come to a boat and ride the bow wave for long distances. Why do they do this? It may simply be fun, or it may allow them to conserve energy; no one really knows.

During the winter pacific gray whales migrate between summer feeding grounds in Alaska and breeding areas in Baja, Mexico, passing through the Santa Barbara Channel. Gray whales are often seen by passengers on whale-watching trips between December and March. Other whale species such as humpbacks, blue, orca and fin whales are less common, but can occasionally be seen during the summer when they come to the channel to feed.

California sea lions are often seen by boaters as they haul-out on sea buoys and offshore rocks, and are frequently encountered by divers and snorkelers in the kelp forest. Less often seen by most people are the enormous colonies of sea lions and seals that come to island beaches to breed. At Point Bennett, on the west end of San Miguel Island, hundreds of thousands of northern elephant seals, California sea lions, northern fur seals and harbor seals all breed at varying times throughout the year. The sight is remarkable, and seen by only a few hundred visitors a year who make the trip out to San Miguel Island and then the six mile hike out to the Point, the westernmost point of all the California Islands.

In many ways pinnipeds are as much terrestrial animals are they marine. For much of their lives they haulout on islands and offshore rocks, either for breeding, to give birth or simply to rest. Their presence in large numbers can have significant impacts on terrestrial systems. For example pinniped carcasses, particularly those of non-surviving pups, provide food for seabirds and bald eagles on the islands. And when animals come farther up the shore away from the beaches and the rocks, they can severly impact the vegetation in those areas. Some pinniped species, especially California sea lions and elephant seals, appear to be increasing in abundance while others like harbor seals may be fewer in number around the islands than they were in the past. Significant changes in sea water temperature like those caused by El Nino events appear to have significant effects on pinniped populations around the Channel Islands.

Birds

Seabirds
Channel Islands National Parkis recognized as an important breeding and resting area for a variety of seabirds. The rich marine food sources and isolated islands support numerous colonies of seabirds. Indeed, the park’s colonies and the surrounding waters that are used for foraging are vital for the survival of several seabird species. Although the mainland may provide roosting areas, in many cases seabirds depend on the islands for breeding and nesting success. Collectively, the islands constitute a major seabird breeding area in the eastern north Pacific, the largest such area in the United States south of the Farallon Islands. For example, half of the world’s population of ashy storm-pestrels and western gulls, 80% of the U.S. breeding population of Xantus's murrels (33.5% of the world’s population and the only breeding ground north of Mexico), and the only major breeding population of California brown pelicans in the western U.S. occur in the park.

Landbirds
Landbird populations and species compo­sitions on the islands can change from year to year, depending on mainland species that reach the islands, changes in habitats, com­petitors or predators that arrive or leave the islands, or areas that are disturbed by people. Most of the bird species probably have experienced a loss of preferred food and shelter due to the alteration of the islands’ scrub habitats.

Nine raptor species live in the park and are primarily seen on Santa Cruz and Santa Rosa. Hawks and owls also occur intermittently on Anacapa, San Miguel, and Santa Barbara, which have limited habitat to support these birds.

Several bird species disappeared from the park during the 20th century. An endemic subspecies of song sparrow (Melospiza melodia graminea) on Santa Barbara was driven to extinction due to habitat destruction by introduced rabbits, direct predation by feral cats, and a fire in 1959 that destroyed much of its habitat. Both bald eagles (Haliaeetus leucocephalus) and peregrine falcons (Falco peregrinus anatum) also formerly bred on the islands, but largely disappeared due to harassment, shooting, egg stealing, and reproductive failure caused by organochlorine pesticides, such as DDT. However, both of these species are making a comeback due to reintroduction efforts. Peregrines were reintroduced on the islands in the 1980s, and there are now about 10 active peregrine falcon nests in the park. A study to determine the feasibility of reintroducing bald eagles began on Santa Cruz Island in summer 2002. Twelve eagles will be released annually on the island during a five-year period.

Garibaldi

Common Name
Garibaldi

Scientific Name
Hypsypops rubicundus

Conservation Status
The Garibaldi is the California State fish and is protected from fishing.

Habitat
These fish mainly live in the kelp forest ecosystem.

Additional Information
This species of damselfish inhabits the warmer waters of the Pacific Ocean from Monterey Bay, California to Baja California along rocky coastal reefs and among kelp forests. They are especially common to the more southern Channel Islands. Easily distinguishable by their vibrant orange color, adult fish may reach up to 17 inches. Juvenile garibaldi fish are yellow-orange with iridescent blue spots and do not mature until five or six years old and eight inches long. They feed on various invertebrates.

Adult male garibaldi carefully constructs circular nest sites about one foot in diameter in shallow reef habitats. They weed out all organisms except for red algae. The more well-prepared and maintained the nests are, the more likely a female will choose that nest to deposit her eggs for fertilization by the hosting male. Once the eggs are fertilized, the male continues to guard the nest often warning divers of their close proximity with a loud thumping noise.

Giant Black Seabass

Common Name
Giant (Black) Sea Bass

Scientific Name
Stereolepis gigas

Habitat
Kelp forests and deep, rocky reefs.

Conservation Status
There is no formal conservation status, but fishing is prohibited in California.

Additional Information
This gentle giant is the largest and most magnificent species of fish in the kelp forest. They are capable of growing to lengths of over 7 feet and weighing 750 pounds! Adults are dark brown to black with large dark spots and a light belly. It is believed that they have the ability to alter their spot pattern at will. As carnivores, they eat many things including Pacific mackerel, shrimp, small sharks, crabs, lobster, anchovies, and squid.

Prior to the 1950’s, this species of bony fish was very common to the near shore waters of Southern California. Due to over-fishing, their population was reduced to critically low levels. In 1982, both commercial and sport fishing of Giant Black Sea Bass was banned in California waters. Since then, the populations have been steadily recovering and encounters by divers are becoming more common.

California Spiny Lobster

Pinnipeds

Point Bennett on the west end of San Miguel Island is known as the only place in the world where six species of pinnipeds breed. San Miguel Island is the northern extent of the range of Guadalupe fur seals and the southern limit of the Northern or Steller sea lion’s range. Both of these animals are listed as threatened and are extremely rare at the Channel Islands now because of declining populations. The other pinnipeds are northern fur seals, California sea lions, northern elephant seals, and harbor seals. Information about each species can be found at the National Marine Mammal Laboratory. the Channel Islands are important to the survival of pinnipeds because most need protected undisturbed beaches to raise their young. Point Bennett is particularly important because it is centrally located, so close to rich feeding grounds for most of these species. Their biggest threats tend to be encounters with fishing gear, pollution, disease, and El Niño.

Common Name
Northern Elephant Seal

Scientific Name
Mirounga angustirostris

Habitat
Elephant seals primarily live on and around sand beaches.

Additional Information
Northern elephant seals, Mirounga angustirostris, are large true seals common in the winter and spring months at the islands. True seals do not have external ear flaps and cannot walk using their hind flippers like sea lions, thus they move by pulling with their front flippers and undulate like slugs.  Hunted nearly to extinction elephant seals have made a phenomenal comeback, numbering around 100,000. Males may weigh up to 6,000 pounds. Females are generally less than 2,000 lbs. After breeding in December and January at the Channel Islands they swim to the Bering Sea to feed on squid and deep water fish. They return to the islands in the spring to molt, then return to Alaska to feed some more. Elephant seals dive continuously during their migrations and have been recorded diving to 4500 ft and up to two hours, though typically shallower and shorter. Pups are weaned after only about one month though they typically triple their birth weight during that time. They are then abandoned and left to learn to swim and find food on their own.

Common name
California Sea Lion

Scientific name
Zalophus californianus

Habitat
Sea lion habitat ranges from sandy beaches to rocky shore cliffs.

Additional Information
California sea lions, Zalophus californianus, are probably the most familiar marine mammal at the islands. These smart, playful animals are often seen playing in the surf or lounging on beaches around San Miguel, Anacapa, and Santa Barbara Islands in particular. Males may reach 8 feet in length and 1000 lbs, females about 220 lbs. They are easily recognized by their pointed nose, external ear flap, “Charlie Chaplin” walk, and loud sometimes incessant barking. Sea lions are very social animals. They can be quite curious in the water coming to investigate divers and boats. On the breeding they are very skittish and will retreat into the water if disturbed. Males set up beach territories and defend their harems from other males. Pups are generally born in June and July and females nurse their pups for nearly year. Sea lions feed on fish and squid near the surface generally but can dive to 500 ft. The 2001 population of California sea lions was estimated at about 200,000 and 80,000 might live at San Miguel Island. The population has been growing steadily since 1975 except for set backs in El Niño years.

Common Name
Harbor Seal

Scientific Name
Phoca vitulina

Habitat
Harbor seals live around sandy beaches.

Harbor seals,

, stick closer to shore than their larger cousins but they are more widespread and are found in both the Pacific and Atlantic oceans. Harbor seals are very shy on land but can be very curious in the water, often coming up to divers to investigate their fins or other gear. Their faces are somewhat rounded and their fur is usually dark gray with darker rings. Adults only reach about 500lbs. Pups are able to swim about an hour after birth, an adaptation to life on small isolated beaches that may become inundated by high tides. Mothers often leave their pups alone on a beach while feeding but will return, so it is important to leave pups alone.

Sunflower Star

Common Name
Sunflower Star

Scientific Name
Pycnopodia helianthoides

Habitat
Near-shore sand and rocky bottom.

Additional Information
The magnificent sunflower star inhabits low intertidal and subtidal areas ranging from Alaska to San Diego, California. Juvenile stars begin life with 5 arms, but once mature, adults have close to 24! They have very soft, spongy skin that comes in a kaleidoscope of colors - purple, green, brown, orange, pink and yellow. They are the largest sea star in the kelp forest reaching lengths of over a meter from tip to tip.

The sunflower star is a voracious predator often traveling up to 40 inches per minute to chase down its prey. This unique species of sea star has a skeleton composed of disconnected pieces. This allows for them to open their mouths wide enough to engulf large prey. They eat sea urchins, snails, clams, sea cucumbers, crabs and even other sea stars.

Island Scrub-Jay

Common Name
Island Scrub-Jay

Scientific Name
Aphelocoma insularis

Conservation Status
Channel Islands National Park has afforded some protection for the island scrub-jay. Sheep and pigs have severely degraded habitat on the islands, but efforts to control their impact have been underway.

Habitat
This species breeds in coast live oak woodland or chaparral dominated by scrub oak on Santa Cruz Island.

Natural History
This species has been split from the Western Scrub-Jay because of its brighter plumage and different genetic makeup. It is restricted to the island of Santa Cruz off the California coast, where its entire population would be threatened by any major disturbance.

Additional Information
Please visit http://audubon2.org/watchlist/viewSpecies.jsp?id=109 for more island scrub-jay facts.

Terrestrial Animals

The number of different animal species found on the Channel Islands, defined as species diversity, is small compared to what would likely be found on a mainland area of similar size. The level of species diversity on islands reflects the challenges to a species of first arriving and then of adapting to unique island conditions. Consequently the ecology of islands is often simpler, but the relationships between species more important and the persisting plants and animals often more unique, than what might be found in mainland habitats. For example the islands within Channel Islands National Park support only four native mammals, the island fox, the island deer mouse, the harvest mouse and the spotted skunk. The fox and the deer mouse have evolved into separate sub-species on each island, resulting in eight unique mammal species found only on the Channel Islands.

The number of reptile and amphibian species (herptiles) is likewise low, and includes four lizards, one salamander, one frog, and two non-venomous snakes. None of these species is found on all of the islands, and no island supports all the species. For example the island night lizard, a threatened species found nowhere else in the world, occurs on only three islands, one within the park and two owned by the U.S. Navy outside park boundaries.

Because it is easier for birds to reach islands than it is for animals that can't fly, bird species diversity on islands is often relatively high. Although the high number is due to migrants, infrequent visitors, and rare species that have arrived on the islands only after being blown off course during spring and summer migrations. Like the island fox, two bird species, the Santa Cruz Island scrub jay and the San Miguel Island song sparrow, have evolved into unique (endemic) island species. The largest landbird native to the islands is the bald eagle -- a species that has recently been reintroduced to the islands.

Bats, though infrequently seen by most visitors, are common on Santa Cruz and Santa Rosa islands. Bats fulfill an important role, or niche, by consuming large numbers of insects and pollinating some plants. Eleven species of bats have been found on Santa Cruz, and the island is home to an important maternity colony of rare Townsend's long-eared bats.

Current research focusing on terrestrial animals includes several studies on the island fox, one on the role of deer mice in affecting vegetation community recovery, and one on the response of lizards to the removal of rats on Anacapa. Ongoing monitoring efforts are measuring changes in amphibian and reptile population biology in response to pig removal on Santa Cruz Island, the number of bats occupying important maternity colonies on Santa Cruz, and mouse population dynamics as they relate to changes in fox numbers on San Miguel Island.

Each island has a unique complement of animals, dependant in many ways on the size of the island. Over time some of these species have evolved into new species, and are present today, while others, like the pygmy mammoth, the Santa Barbara Island song sparrow, and the giant deer mouse, evolved into unique island species before becoming extinct. While it may not appear so to relatively short-lived humans, the islands are still changing and evolving, and what lives here in the future may be very different than what we see today.

Golden Eagle

Common Name
Golden Eagle

Scientific Name
Aquila chrysaetos

Habitat
The golden eagle seeks open terrain throughout mountains, foothills, and plains.

Natural History
This powerful bird of pretty is widespread in the wilder country of North America, Europe, and Asia. Approximately the size of the bald eagle, the golden is less of a scavenger and more of a predator, regularly taking prey up to the size of foxes and cranes. Also spiritually important to many Native American tribes.

Additional Information
Golden eagles are currently being removed from the park because golden eagle predation is the primary source of mortality for island foxes and is likely responsible for the massive island fox decline from 1994–2000. Until recently, golden eagles never bred on the Channel Islands. They are able to exist in the park because of the occurrence of feral pigs on Santa Cruz Island, and because bald eagles no longer are present to deter them. They were discovered in the winter of 2002–03 to also be nesting on Santa Rosa. The Santa Cruz Predatory Bird Research Group, with the support of the Park Service and The Nature Conservancy, has been relocating golden eagles to distant sites on the California mainland. To date, 32 golden eagles have been removed from Santa Cruz and Santa Rosa Islands, and as of February 2005 it is thought that at least 10 golden eagles remain on the islands. However, until bald eagles become reestablished and/or feral pigs are removed, other golden eagles may come from the mainland to the islands.

Island Spotted Skunk

Common Name
Island Spotted Skunk

Scientific Name
Spilogale gracilis amphiala

Habitat
Hills and steep canyons covered by grasses, chaparral, coastal sage, and scrub oak throughout Santa Rosa and Santa Cruz Islands.

Natural History
The recent decline of the endemic island fox (Urocyon littoralis) on the northern Channel Islands prompted investigation on the status of the island spotted skunk on Santa Rosa Island. Little is known about the island spotted skunk on Santa Cruz Island, and no data have been collected on the status of the Santa Rosa Island population.

Island Fox

The island fox (Urocyon littoralis) is the largest of the Channel Islands' native mammals. A descendent of the mainland gray fox, the island fox evolved into a unique species over 10,000 years ago. The island fox has similar markings to its ancestor, but is one-third smaller.

Environmental and ecological factors such as drought or food scarcity may have contributed to the natural selection for a smaller size. At 12 to 13 inches in height and 4 to 5 pounds, the island fox is about the size of a housecat. Island foxes have gray coloring on the back, rust coloring on the sides, and white underneath. The face has a distinctive black, white, and rufous-colored patterns.

Scientific Classification & Taxonomy

The scientific name of the Island fox is Urocyon littoralis. It shares the genus with its mainland ancestor the gray fox, Urocyon cineroargenteus. Littoralis translates from Latin as "situated or growing on or near a shore especially of the sea." Island foxes are distributed as six different subspecies, one on each of the six Channel Islands on which they occur. Foxes from separate islands are still capable of interbreeding, but are physically and genetically distinct enough to be recognized as separate subspecies. For example, the average number of caudal (tail) vertebrae differs significantly from island to island. Subspecies are named for their island of origin.

Island Fox Subspecies

Taxonomy is the orderly classification of living things in terms of their relationships with one another. Here is how the island fox relates to other animals.

Island Fox Fossil Record

The fossil record shows evidence of foxes on Santa Rosa Island dating back 10,400 to 16,000 years ago. How did the gray fox get across the water barrier of Santa Barbara Channel? The most plausible and accepted theory is one of "rafting." During the last Ice Age, as the ocean levels lowered and the distance between the mainland and the islands shrunk, the northern islands became one large island called "Santarosae." The gray fox could have rafted on debris propelled by storms and/or currents. As the climate warmed and the ocean levels began to rise, Santarosae became the islands of Anacapa, Santa Cruz, Santa Rosa, and San Miguel. Due to the lack of a fresh water source, the foxes did not persist on Anacapa, but the other three islands had suitable habitat for foxes.

Island foxes were probably brought to the southern Channel Islands of Santa Catalina, San Nicolas, and San Clemente by the Chumash native people who traded with the Gabrielino people of the southern islands. The Chumash considered the fox to be a sacred animal--a pet of the sun, and possibly a dream helper. The island Chumash performed a fox dance and probably used the pelts of foxes to make articles like arrow quivers, capes, and headdresses.

Island Fox Habits and Behavior

Island foxes communicate with one another through sight, sound, and smell. Visually, island foxes show signs of dominance or submission through facial expressions and body posture. They communicate auditorily by barking and sometimes growling. Their keen sense of smell plays an important role in the marking of territories. Island foxes are known to scent-mark their territories with a few drops of urine and tend to concentrate scats in particular areas, often conspicuously positioned on well-traveled paths. Island fox tracks are similar to those of the gray fox only smaller.

Compared with the gray fox, island foxes are relatively diurnal (active during daylight hours) with peaks in activity occurring at dusk and dawn. Island fox diets consist primarily of fruits from plants like the sea fig, insects like the Jeruasalem cricket, and one of the few small mammals found on the islands, the deer mouse. Occasionally, foxes forage along the shoreline for crabs and other marine invertebrates.

Island Fox Reproduction

Island foxes are generally monogamous (mate for life), and breed only once a year. Pairs are seen together frequently beginning in January, and mating takes place in late February to early March. The gestation period is thought to be similar to the gray fox, which is around 52 days, and pups are born from late April through early May. Litter size ranges from one to as many as five pups, but two or three is considered average. Born in the protection of a den, pups are blind and helpless with short dark brown hair at birth. They emerge from the den at about one month of age, much furrier but still considerably darker than adults. They begin to resemble their parents by late summer.

It is believed that island fox pups undergo a period of extended parental care. In a recent study of island foxes, scientists found adults and pups in the same trap on 22 occasions. In 24 traps containing only pups, they found killed mice and other prey items outside the traps, apparently left by the parents for their young. As with most wild canids, males play an important role in the rearing of young.

Island Night Lizard

Common Name
Island Night Lizard

Scientific Name
Xantusia riversiana

Conservation Status
Listed as threatened in 1977, the night lizard population has rebounded since then.

Habitat
The island night lizard prefers boxthorn, prickly pear cactus, and cracks and crevices in and around rock outcrops and surface boulders.

Additional Information
Island night lizards (Xantusia riversiana) are an endemic Channel Islands reptile, known only to occur on Santa Barbara Island in the park and on San Nicolas and San Clemente Islands. They are the most morphologically distinct of the endemic vertebrates on the Channel Islands, indicating they have been isolated from the mainland for a long time. The best habitats for the lizards are boxthorn (Lycium californicum), prickly pear cactus (Opuntia oricola and O. littoralis), and cracks and crevices in and around rock outcrops and surface boulders. These areas provide protection from predators. They are also often found under rocks, driftwood, and fallen branches. Suitable habitat on Santa Barbara is in all of the canyons and on some of the sea cliffs, especially on the south side of Signal Peak. Island night lizards are very sedentary and have very small home ranges, averaging about 183 square feet (17 square meters). They are most active at midday. The lizards breed in April, with young being born in September.

Fellers and Drost found densities of 1,300 lizards per acre in boxthorn and 1,000 lizards per acre in prickly pear. This high density is probably due to a combination of factors, including the lizard’s low metabolism, diverse diet, sedentary nature, and small, overlapping home ranges.

Although abundant in their favored habitats, island night lizards are still sensitive to disturbance. Individual lizards can be trampled and habitat damaged by people walking off trail.

On August 11, 1977, the U.S. Fish and Wildlife Service listed the island night lizard as a threatened species because of its restricted range and apparently low population levels on Santa Barbara and San Nicolas islands. Their populations were thought to have been reduced due to past farming and grazing, fire, and the introduction of nonnative animals and plants. However, Feller and Drost estimated that the total population on Santa Barbara was at least 17,600, and concluded that the population was not threatened with extinction as was previously thought.

Townsend's Big-eared Bat

Common Name
Townsend's Big-eared Bats

Scientific Name
Corynorhinus townsendii

Conservation Status
Townsend's big-eared bats are listed as an Endangered species in Washington, a Sensitive species in Oregon, a Species of Special Concern in Texas, Montana and California, and are on the Blue List in British Columbia.

Habitat
They prefer open roosting areas in large rooms and do not tuck themselves into cracks and crevices like many bat species do.

Additional Information

Townsend's big-eared bats are medium-sized, light brown bats with very large ears. They specialize in eating moths and other insects. They occur throughout the Western U.S. and use a variety of habitats, almost always near caves or cave-like roosting areas. They prefer open roosting areas in large rooms and do not tuck themselves into cracks and crevices like many bat species do. Their preference for open spaces in caves makes them easy to detect and vulnerable to vandalism.

Summer maternity colonies range in size from a few dozen to hundreds of individuals. These colonies form between March and June (depending on climate), with pups born between May and July. Maternity colonies choose sites that have warm, stable temperatures for pup rearing. Males remain solitary during the maternity season. Winter hibernation colonies are comprised of males and females and range in size from a few individuals to several hundred bats.Townsend's big-eared bats are very sedentary, with movement by females during the nursing season rarely exceeding 15 km., and movement at other times usually being less than 50 km. If undisturbed, colonies will occupy the same site indefinitely.

Status

Townsends big-eared bats occur throughout the Western U.S from Texas to British Columbia, from sea-level to over 10,000 feet. Distribution is strongly correlated with the availability of caves and cave-like roosting habitat, with population centers occurring in areas dominated by exposed, cavity forming rock and/or historic mining districts. They are generally in decline in most areas, and are listed as an Endangered species in Washington, a Sensitive species in Oregon, a Species of Special Concern in Texas, Montana and California, are on the Blue List in British Columbia ('rare or uncommon, and may be susceptible to large-scale disturbances'). They are considered Sensitive by the U.S. Forest Service.

A study sponsored by the California Department of Fish and Game in the late 1980's documented a population decline of between 40 and 60% in the past 30 years. Only about half of the maternity colonies known to exist in California prior to 1980 were relocated by 1991, resulting in an estimated 54% decline of adult females. Only three maternity colonies increased in size during the period, and all three are located in National Park areas (Point Reyes National Park, Lava Beds National Monument, and Pinnacles National Monument). Of the 23 roosts that are no longer available to bats, 9 (mostly buildings) have been demolished, 4 (all buildings) have burned, 4 (all buildings) have been renovated in such a way that bats were excluded, and 6 (including buildings, caves, mines, and a water diversion tunnel) have had the entrance closed.

Threats

The primary threat to C. townsendii is almost certainly disturbance or destruction of roost sites (e.g., recreational caving, mine reclamation, renewed mining in historic districts). Surveys conducted in Oregon and California indicate that historic roost sites have been negatively impacted in recent years with most reported colonies exhibiting moderate to sizable reduction in numbers. Additional surveys in Utah indicate that several historic maternity sites have been abandoned, although it is not known if these colonies have relocated.

This species is very sensitive to disturbance events and has been documented to abandon roost sites after human visitation. In California and at a number of sites in the east, depressed populations have recovered with the protection (i.e., gating) of roosts. In large portions of its western range, dependence upon abandoned mines puts this species at risk if mine reclamation and renewed mining projects do not mitigate for roost loss, or do not conduct adequate biological surveys prior to mine closure. Both roosting and foraging habitat my be impacted by timber harvest practices. Pesticide spraying in forested and agricultural areas may affect the prey base.

Townsend's big-eared bats on Santa Cruz Island 

Townsend's big-eared bats were first observed on Santa Cruz Island in the historic 2-story ranch house at Prisoner's Harbor in 1939. At that time the maternity roost was estimated to contain "well over 300" individuals. During the mid-1960's UCSB researchers found the colony still active at Prisoners, but this building was removed around that time. Despite extensive searching from 1974 to 1988, no other big-eared bats were seen on Santa Cruz.

In 1991 Dr. Pat Brown of UCLA was made aware of a colony of Townsend's roosting in the bakery room of the Scorpion adobe building. This room was closed until 1984, so it is unknown whether or not there was a maternity colony on the island between the period when the Prisoners' building was lost and the Scorpion bakery room was opened. Dr. Brown believes that prior to building construction, natural caves and rock formations served as roost sites.

Dr. Brown's research in the early 1990's included radio-tracking of bats mist-netted at the Scorpion colony in the late summer of 1992. (Bats were netted at the end of the maternity season when young bats were old enough to fly on their own.) Radio-tracking showed that the Scorpion bats foraged up to 5 kilometers away to feed on moths and other insects among the native oak and ironwood forest on the north-facing slopes of Scorpion Canyon, returning to the roost each morning. She found that the bats used shallow rock caves as night roosts but rarely as day roosts, and no reproduction was noted from these cave areas.

Bi-annual emergence counts (May and August) and visual surveys of the bakery colony conducted since 2002 indicate that a large maternity colony continues to use the building between April, when the room is made available, and at least early September. According to the 1994 Department of Fish and Game report, the Scorpion roost is one of only two or three coastal maternity colonies known to exist south of Pt.

Paleo Animals

The most notable animal fossils, and the best studied aspect of island paleontology, are the pygmy mammoth (Mammuthus exilis). Remains of this species have been known on the Channel Islands since 1856 when they were discovered by a coast and geodetic survey. In 1994 a nearly complete adult skeleton was discovered and excavated on Santa Rosa.

Terrestrial Invasive

Plants and animals living on islands are especially vulnerable to extinction due to the physical boundaries, limited populations, and lack of genetic variability. One threat to these island species are invasive weeds. The term "invasive weed" is generally used to describe non-native plants that are unwanted and grow or spread aggressively. Invasive weeds can take over important wildlife habitat, devastating shelter and forage while reducing the diversity and quality of native habitat. Weeds often do not hold and protect the soil the way native plants do, so erosion increases and causes sedimentation of streams, harming fish populations and water quality. The primary visitor landing points on the park islands are often where we first find non-native plants. Nearly half of the endangered plants and animals in the United States have been negatively affected by invasive species. Invasive species cause an estimated $138 billion in economic damage each year in the United States.

Channel Islands National Park is vulnerable to colonization and recolonization by non-native plants because of human transport to the islands and natural processes such as wind and sea currents. As a result, more than 25 percent of the plants known from the park are introduced. As the number and variety of non-native plants increase on the nearby mainland and as the park visitation and operations increase, the chance of accidental introductions of plants also increases. Recently arrived non-native plants are easy to eliminate if detected and acted upon promptly. The cost and feasibility of control increases exponentially each year a non-native species is left to spread uncontrolled.

Paleontological Resources

The Channel Islands, particularly San Miguel, Santa Rosa, and Santa Cruz, contain numerous plant and animal fossils that illuminate the past natural history of the California coastal region. This fossil record offers the opportunity to study fauna speciation and evolution, the development of plant and animal communities, their adaptations to varying climate conditions, and the effects of human colonization on the fauna. As a result, the Channel Islands are of special interest to researchers, and a number of paleontological studies have been done on the islands.

Research indicates that the Pleistocene fauna of the Channel Islands is unique in several respects. First, it contains several extinct species, including pygmy mammoth, an owl, a flightless goose, a puffin, and a vampire bat, and two species of giant mouse. The park also contains the best representation of Pleistocene marine avifauna on the Pacific coast, with over 70 species having been discovered on San Miguel.

The most notable animal fossils, and the best studied aspect of island paleontology, are the pygmy mammoth (Mammuthus exilis). Remains of this species have been known on the Channel Islands since 1856 when they were discovered by a coast and geodetic survey. In 1994 a nearly complete adult skeleton was discovered and excavated on Santa Rosa. Pygmy mammoths descended from full-sized Columbia mammoths that swam across the Santa Barbara Channel to the islands during the Pleistocene. It is believed that during that period the northern Channel Islands were connected into one large island because of the lowered sea levels. Apparently pygmy mammoths died off at about the end of the Pleistocene (12,000 years ago). Pygmy mammoth fossil bones have been found on more than 140 sites on San Miguel, Santa Rosa, and Santa Cruz. These are the only known remains in the world. On Santa Rosa, fossils are often exposed in sands, silts, and gravels of Pleistocene age anywhere on the island. Most specimens have been found in the sediments comprising the coastal terraces of the island. Due to the numerous questions about many aspects of this species' evolution and development, any fossil may potentially be of crucial importance in answering important research questions.

Another important paleontological resource is the caliche fossil forests, or rhizoconcretions, on San Miguel. Three major caliche forests are found on the island. These fossils are calcium carbonate-encrusted casts of vegetation buried by sand dunes more than 14,000 years ago. They provide evidence that the island once supported large trees and shrubs. These caliche casts are fragile and easily broken.

The Channel Islands are a continuation of the Santa Monica Mountains on the main­land, though they were never connected above sea level, and are composed of many of the same Tertiary marine formations. As such, they also have many of the same marine invertebrate fossils. Although there are studies on the invertebrate paleontology of these formations in the Santa Monica Mountains, there has not been research done on their counterparts on the islands. There have been some studies of the Pleistocene invertebrate fauna of the islands, but as is the case of the invertebrates from the Tertiary marine sediments much remains to be done.

Although researchers have learned quite a bit about some of the park's fossils, such as the pygmy mammoth, paleontological resources on the Channel Islands have not been very well studied. Fossil localities containing smaller terrestrial species of Pleistocene age and invertebrate fossils embedded in the Miocene strata of the islands remain unstudied. In addition, natural and human-induced erosion probably has degraded or destroyed fossil sites; unless collected properly and promptly, bones that are exposed by erosion may be scattered and lost.

Kelp Forests

Ecology and Importance

Kelp forests are true forests providing shelter and food for over 1,000 species of animals and plants that live within them. Fish such as rockfish, kelp bass and California Sheephead hide among kelp fronds to avoid predators and to search for smaller prey. The tall fronds rising to the surface provide substrate and protection for many invertebrate species. Others, like the sea urchins, wavy turban snails, and abalone are there to dine on the kelp blades.

Giant kelp, Macrocystis pyrifera, may grow at depths below 100ft, sending their leaf like fronds to the surface to create a dense canopy. Holdfasts, root like structures that anchor the kelp to the bottom, are excellent hiding places and act as nurseries to juvenile invertebrates such as spiny lobster, sea cucumber, and sea urchins. The blades of kelp help slow water movement within the kelp forest, providing more refuges for smaller organisms such as juvenile rockfish.

Kelp forests of the Channel Islands experience both warm water currents from the South and cold water currents from the North. This mixing of currents creates a highly productive system and a diversity of organisms that is only found over a much greater area of the California coast. Some examples of warmer water species include Garibaldi, moray eels, and the spiny lobster. Examples of colder water organisms include black rockfish, and the sunflower star.

Kelps are harvested for alginates, products that are used as thickeners and stabilizers in many foods and other products from ice cream to soaps and shampoos. Kelp forests also provide the diversity, color, and structure that make them a favorite of divers and photographers.

Rocky Intertidal Zone

Undisturbed tidepools are one of the many exquisitely rich seascapes greeting a visitor who ventures into an island's splash zone at Channel Islands National Park. Covered and uncovered twice each day by tides, the Park's rocky intertidal (roughly meaning "between tides") is home to an abundance and diversity of marine life, unparalleled by even the most unspoiled, remote shorelines along California's mainland.

Few other places promise such a captivating and wonderful array of marine life in such a relatively short distance - from the lush intertidal algal and plant growth that provide habitat for so many marine animals, to the strange and wonderful invertebrate creatures that lie beneath. Whether exploring the tideline by foot, kayak or snorkel, or just spending an hour or two with a naturalist at the pier on East Anacapa Island, one can't help but come away with an heightened appreciation of just how remarkably rich and diverse these islands are for its intertidal (and subtidal) habitats and inhabitants!

Several major factors contribute to the richness of sea life around the Channel Islands: 1) their location near the boundary of two major biogeographic provinces (the Oregonian and the Californian); 2) their diversity of habitat types and exposure to varying oceanographic conditions; 3) their high productivity resulting from upwelling of cold nutrient-rich water off Pt. Conception; and 4) their isolation from the mainland, leaving the islands' coastline further removed from the risks of some human-induced impacts.

However remote, trampling by visitors, harvest of resources, foraging and/or invasion by alien species, and episodic (or chronic) pollution including oil spills remain the biggest threats to this fascinating group of marine flora and fauna occurring among the islands' remote rocky intertidal boulder fields, headlands, sandy beaches, and within surfgrass or kelp-dominated habitats. These strangely wonderful plants and animals - mostly resilient and adapted to the rise and fall each day of the tide and to the variable nature of the area's ocean currents - remain ever vulnerable to rapid and/or irreversible changes affecting the adjacent marine ecosystem.