The U.S. state of California has instituted numerous conservation programs, policies, laws, reserves and Habitat restoration projects throughout the state to facilitate the health and migration of the western population of the monarch butterfly (Danaus plexippus). The population of western monarchs require very different breeding and overwintering habitat when compared to the eastern population of monarch butterflies. They require specific micro-climatic conditions to survive the winter and they are sensitive to habitat changes at the overwintering sites. The large aggregations of butterflies are seen as the most vulnerable at their overwintering locations along the coast. Many monarch overwintering sites are contained within the "coastal zone"; an area defined by the Coastal Zone Management Act [1] to be 1000 yards inland from the high tide mark. Large number of overwintering sites are outside the coastal zone. There are more than 450 overwintering sites in California.
Conservationists promote habitat conservation by identifying trees that are necessary for roosting. They suggest that roosting sites be identified and designed to prevent degradation of the area. They also suggest that an environmental impact statement be filed when construction is done near overwintering roasts. Removal of trees within the perimeter of the habitat should be prohibited. Tree maintenance should be performed by experts in the field. They propose that it should be unlawful to remove trees, under-story plants and vegetation near roosting sites. Reforestation efforts should be instituted. Erosion control needs to be taken into account to maintain suitable habitat. Conservationists suggest that wood-burning fireplaces and structures should not be built near roosting sites.[ citation needed ]
The International Environmental Law project issued a policy statement regarding eucalyptus management at monarch overwintering sites. [2] This group recognizes the wide variety of tree species that monarchs utilize in their overwintering roosts. The Xerxes society recommends that eucalyptus trees remain unmolested, if monarchs roost on the trees. [3] [4]
The International Environmental Law Project of 2012 has proposed model legislation and recommends the following:
Participants in Monarch Watch's waystation program have planted acres of native milkweeds to encourage larval growth for monarchs. These way stations also provide nectaring plants for adult monarchs. [18]
Most locales do not have laws or policies concerning the removal or alteration of trees within a designated monarch overwintering site. Alteration of trees requires a permit in Capitola and Goleta. Studies continue to determine the efficacy of the continued use of eucalyptus trees as roosting trees. [19] Large gaps in the tree canopies at the overwintering sites in California affect the suitability of the roosts. [20]
Large number of overwintering sites are outside the coastal zone. There are more than 450 overwintering sites in California documented since the 1980s.[ citation needed ]
Monarchs are protected from the effects of land development, tourism in the 270 California state parks. The activities of visitors to the parks are regulated to include the prohibition of molesting, hunting, disturbing, harming, feeding, touching, teasing, injuring, trapping, taking, netting, poisoning any animal or trees. [21] The collecting, capturing and killing of any animals and the destruction of native vegetation is prohibited in the parks. Overwintering sites occur near beaches, universities and other state lands. [22] State parks do not have specific policies regarding the maintenance of trees on which the monarchs overwinter. [23] California historical sites are exempt from having to create monarch conservation plans. [24]
Twenty of state parks contain monarch overwintering groves.
The habitat of the western population of monarch butterflies is protected from visitors and commercial activities on federal land. Plant collection, animal collection, and the disruption of habitat are not permitted. Federal lands do not possess policies or guidelines regarding the maintenance of trees on which the monarchs overwinter. [23]
Overwintering monarch roosts have been observed at the Los Padres National Forest, Sycamore Canyon, Pruitt Creek, the Marin Headlands, Stinson Beach, Tennessee Valley, Muir Beach, Fort Barry, Fort Baker, and the Point Reyes National Seashore. [34]
Lands are managed by the Department of Defense, Vandenberg Air Force Base and Camp Pendleton are known to host monarch overwintering sites. Monarch butterfly habitat protection does not supersede the land use needs of the military. [35]
The California Department of Fish and Game does not have the authority to regulate the collection and habitat changes that affect the monarch. Local ordinances sometimes provide guidelines for monarch conservation and any developmental activity. Local ordinances encourage the removal of non-native species. This is in conflict with the preservation of monarch overwintering sites because monarchs often overwinter in stands of non-native eucalyptus trees. There are some local ordinances that regulate tree removal and cutting. [36]
Overwintering monarchs, thousands to tens of thousands have historically roosted at Ardenwood Historic Farm in Fremont. [37] These roosts are protected by County regulations.
The East Bay Regional Park District raises awareness with its monarch educational programs to raise awareness of the wintering butterflies. The East Bay regional Park District has a master plan that "pledges to"identify, evaluate, conserve, enhance, and restore rare, threatened, endangered, or locally important species of plants and animals and their habitats". [38]
Los Angeles County contains at least 44 monarch overwintering roosts. These roosts exist mainly within public parks. The City of Santa Monica, City of Long Beach, and Redondo Beach hosts small sites of overwintering roosts.
Mendocino County hosts the northernmost roosting sites of the overwintering monarchs in the southern part of the county, but they are only present for several weeks during the winter. It is considered a transient site. [39]
Monterey County contains roosts of thousands of butterflies.
Pacific Grove contains two large overwintering sites, including Monarch Grove Sanctuary. These sites are populated on a consistent basis. [36] The city has passed ordinances specifically designed to protect the monarchs and the trees on which they produced. Tree removal and maintenance is highly regulated. [40] [41]
Huntington Beach contains four monarch overwintering roasts which are located in city-owned parks. The roosts are small but city regulations mandate their protection. [42]
There is only one roosting site in the Chula Vista containing about 50 individual butterflies. This site is protected by city ordinances. [43]
Overwintering roosts of monarchs have been observed in the city of San Diego since the 1920s. No regulations are in place to protect the monarchs' further habitat destruction. [44]
Santa Barbara County contains 132 overwintering roosts. These can be found on state or federal land, and public and private property.
Roosts in the city of Carpinteria are near Carpinteria Creek, Recon Creek, the Carpinteria business Park, and the Carpinteria oil and gas plant buffer zone. "Also known as Chevron Park". These roosts contain tens of thousands to thousands of monarchs on a consistent basis. Carpinteria restricts the removal of trees and requires that development be restricted near the trees.
The city of Goleta butterfly counts in recent years have identified tens of thousands of monarchs roosting there. A fire in the past destroyed one of the sites. The overwintering sites in the city of Goleta are protected by relatively rigorous regulations. [45]
California's monarch population has declined sharply from 4.5 million in the 1980s. The population initially dropped to nearly 200,000 and had an even greater decrease during 2018. That year, the population fell to nearly 30,000. By November 2020, the population had dropped to fewer than 2,000, representing a 99% collapse in three decades. [46]
The Xerces Society for Invertebrate Conservation has issued a brochure identifying priority action zones in California for recovering western monarchs. The brochure identifies measures for restoring monarch populations in each of five zones within the state. [47]
The monarch butterfly or simply monarch is a milkweed butterfly in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. It is among the most familiar of North American butterflies and an iconic pollinator, although it is not an especially effective pollinator of milkweeds. Its wings feature an easily recognizable black, orange, and white pattern, with a wingspan of 8.9–10.2 cm (3.5–4.0 in). A Müllerian mimic, the viceroy butterfly, is similar in color and pattern, but is markedly smaller and has an extra black stripe across each hindwing.
Fitzgerald Marine Reserve is a marine reserve in California on the Pacific Ocean, located just north of Pillar Point Harbor and Mavericks in the San Mateo County community of Moss Beach. Moss Beach is located approximately 20 miles (32 km) south of San Francisco and 50 miles (80 km) north of Santa Cruz. The reserve is a 32-acre (0.13 km2) holding which extends from Montara light station at the north to Pillar Point on the south. The reserve consists of a three-mile stretch of beach, tidepool habitat, marsh, erosive bluffs, clifftop trail and cypress and eucalyptus forests. The property is owned by the State of California and managed by San Mateo County as a county park and nature preserve. The reserve is administratively assigned to be part of the Monterey Bay National Marine Sanctuary. Adjacent to and possibly within the reserve is an endangered species of butterfly, the San Bruno elfin butterfly.
The Xerces Society for Invertebrate Conservation is a non-profit environmental organization that focuses on the conservation of invertebrates considered to be essential to biological diversity and ecosystem health. It is named in honor of an extinct California butterfly, the Xerces blue.
Asclepias incarnata, the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a garden plant for its flowers, which attract butterflies and other pollinators with nectar. Like most other milkweeds, it has latex containing toxic chemicals, a characteristic that repels insects and other herbivorous animals.
Natural Bridges State Beach is a 65-acre (26 ha) California state park in Santa Cruz, California, in the United States. The park features a natural bridge across a section of the beach and a eucalyptus grove provides habitat for monarch butterflies. During monarch butterfly migration, Monarch Butterfly Natural Preserve has up to 150,000 monarch butterflies from October through early February.
Robert Michael Pyle is an American lepidopterist, writer, teacher, and founder of the Xerces Society for Invertebrate Conservation. Much of his life story is told in the 2020 feature film The Dark Divide, where Pyle is played by David Cross.
Butterfly gardening is a way to create, improve, and maintain habitat for lepidopterans including butterflies, skippers, and moths. Butterflies have four distinct life stages—egg, larva, chrysalis, and adult. In order to support and sustain butterfly populations, an ideal butterfly garden contains habitat for each life stage.
The Pacific Grove Museum of Natural History is a museum of natural history located near the Monterey Bay Aquarium in Pacific Grove, California, United States. The museum is a living field guide of the California Central Coast showcasing local native plants, animals, geology, and cultural histories.
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Asclepias viridis is a species of milkweed, a plant in the dogbane family known by the common names green milkweed, green antelopehorn and spider milkweed. The Latin word viridis means green. The plant is native to the midwestern, south central and southeastern United States, as well as to the southeastern portion of the western United States.
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Monarch butterfly migration is the phenomenon, mainly across North America, where the subspecies Danaus plexippus plexippus migrates each autumn to overwintering sites on the West Coast of California or mountainous sites in Central Mexico. Other populations from around the world perform minor migrations or none at all. This massive movement of butterflies has been recognized as "one of the most spectacular natural phenomena in the world".
Setirostris eleryi is a species of small insectivorous bat found in inland eastern Australia. It is the sole species of the molossid genus Setirostris, a name that refers to the coarse bristles on their faces. Earlier common names have referred to this unique feature, and the 'free-tail' that is a common feature of its microchiropteran family, the Molossidae; no single common name emerged during the taxonomic revisions that identified what was referred to as the bristle-faced freetail.
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The North American migratory populations, however, have experienced dramatic declines over the past twenty years due to a suite of interrelated factors including habitat loss in breeding and overwintering sites, habitat degradation, disease, pesticide exposure, and climate change. The most recent population census of the western population, conducted annually by The Xerces Society for Invertebrate Conservation, revealed that fewer than 2,000 individual butterflies currently seek shelter in California's coastal groves. Western monarch numbers have dropped by 99% from an estimated 4 million butterflies just twenty years ago.