Ecology Guadalupe Island

1 ecology

1.1 habitat types
1.2 endemism
1.3 extinctions

ecology

nasa satellite image



great white shark off isla guadalupe



great white shark off isla guadalupe

guadalupe island major destination russian , american fur hunters seeking guadalupe fur seal (arctocephalus townsendi) in 18th , 19th centuries, until extinct 1844. captain auguste duhaut-cilly reported in 1827 sandwich islands (hawaiian islands) brig had spent several months there , collected 3 thousand sealskins . northern elephant seal (mirounga angustirostris) ruthlessly hunted oil in blubber. thought extinct in 1884 until remnant population of 8 individuals discovered on guadalupe island in 1892 smithsonian expedition, promptly killed 7 of them collections. elephant seals managed survive, , protected mexican government in 1922. surviving northern elephant seals share same male ancestor.

guadalupe shares california chaparral , woodlands ecoregion channel islands of california in united states, island @ 1 time practically denuded of plants higher few centimeters 100,000 feral goats.

originally brought there in 19th century european whalers , sealers provisions when stopping over, population eliminated vegetation; number of goats declined few thousand. main impact of goat population before collapse, turn of 19th/20th century. naturalist a.w. anthony wrote in 1901:

directly due despised billy-goat many interesting species of plants formerly abundant extinct, , 1 or more of birds peculiar island has disappeared, , others following rapidly.

after crash, goat population once again grew, time more slowly, until had reached new, lower carrying capacity @ maybe 10,000–20,000 in modern times. island had been nature conservancy area since august 16, 1928, making 1 of oldest reserves in mexico. eradication of goats long envisioned, logistical difficulties such island size , lack of suitable spots landing , encamping hunters , material prevented this. of june 2005, after many years of false starts, mexican government has completed round-up , evacuation of remaining goat population , guadalupe has been designated biosphere reserve.

french sea captain auguste duhaut-cilly remarked on tall trees on north of guadalupe island sailed past on january 2, 1827. of large tree species on guadalupe island (guadalupe palm, guadalupe cypress, island oak, , guadalupe pine), there old individuals left; california juniper had entirely disappeared. goats ate seedlings managed germinate, no regeneration of trees possible. water, formerly plentiful common fogs condensed in forests of northern end of island, today occurs in few scattered pools , springs. because springs critical emergency water supply human inhabitants, protective measures including goat fences installed beginning in 2000, allowing new seedlings of many species survive first time in 150 years. seacology, non-profit environmental group located in berkeley, ca, provided funding island conservation & ecology group construction of ten fenced exclosures keep goats out of sensitive areas of guadalupe island.

in november 1850, u.s. army lt. george h. derby passed island on expedition in u.s. transport invincible. described thus: island 15 miles length , 5 in width. rocky + mountainous capped vegetation , reputed thickly inhabited wild goats of unusual size. water found upon eastern shore , island visited small vessels engaged in capture of sea elephant numbers of animals found upon coast.

many island or marine species reside on or near guadalupe frequent channel islands, , vice versa. in stark contrast rampant extinction of terrestrial life happened @ same time, guadalupe last refuge northern elephant seal (mirounga angustirostris) , guadalupe fur seal (arctocephalus townsendi) in 1890s. island has been pinniped sanctuary since 1975.

guadalupe considered 1 of best spots in world sightings of great white shark, possibly because of large population of pinnipeds.

habitat types

before removal of goats, surveys found 8 major land habitats on guadalupe:

giant coreopsis (coreopsis gigantea)



cylindropuntia prolifera



perityle emoryi



pinus radiata cone

a ninth habitat type, california juniper woodland , extending on central plateau below cypress forest, entirely gone 1906. other endemic lifeforms underwent coextinction forever remain unknown.

endemism

animals:

guadalupe fur seal (arctocephalus townsendi)



guadalupe fur seal (arctocephalus townsendi) – major breeding site
townsend s storm petrel (oceanodroma socorroensis) – known breeding site
ainley s storm petrel (oceanodroma cheimomnestes) – known breeding site
guadalupe rock wren (salpinctes obsoletus guadalupensis) – endemic
guadalupe house finch (carpodacus mexicanus amplus) – endemic
guadalupe pipefish (syngnathus insulae) – endemic
guadalupe junco (junco insularis) – endemic
guadalupe caracara (caracara lutosa) – endemic, extinct
endemic spiders:

habronattus gigas
herpyllus giganteus
kibramoa isolata
sergiolus guadalupensis

plants:

baeriopsis guadalupensis – near-endemic
brahea edulis (guadalupe palm) – endemic
camissonia guadalupensis ssp. guadalupensis – endemic
castilleja fruticosa – endemic
cistanthe guadalupensis – endemic
cupressus guadalupensis var. guadalupensis (guadalupe cypress) – endemic
cryptantha foliosa – endemic
deinandra frutescens – endemic
deinandra greeneana ssp. greeneana – endemic
deinandra palmeri – endemic
dudleya guadalupensis – endemic
dudleya virens ssp. extima – endemic
eriogonum zapatoense – endemic
erysimum moranii – endemic
eschscholzia elegans – near-endemic
eschscholzia palmeri – endemic
galium angulosum – endemic
githopsis diffusa var. guadalupensis – endemic
hemizonia frutescens – endemic
hemizonia greeneana ssp. greeneana – endemic
hemizonia palmeri – endemic
heteromeles arbutifolia var. macrocarpa – endemic
lavatera lindsayi – endemic
lupinus niveus – endemic
marah guadalupensis – near-endemic or endemic
perityle incana – endemic
phacelia phyllomanica – endemic
pinus radiata var. binata (guadalupe island monterey pine) – near-endemic or endemic
satureja palmeri – endemic; rediscovered in 2001–2003 surveys
senecio palmeri – endemic
sphaeralcea palmeri – endemic
sphaeralcea sulphurea – endemic
stephanomeria guadalupensis – endemic
triteleia guadalupensis – endemic

extinctions

numerous taxa have gone extinct due habitat destruction goats, in turn rendered endemic fauna vulnerable predation introduced cats , adverse weather depriving them of shelter.

there have been 5–6 extinctions of birds:

guadalupe bewick s wren (thryomanes bewickii brevicauda), late 1890s,
guadalupe spotted towhee (pipilo maculatus consobrinus), late 1890s
the guadalupe caracara (polyborus lutosus) intentionally made extinct humans around 1901, ironically because preyed on young goats.
guadalupe flicker (colaptes cafer rufipileus), c. 1910 – island later recolonized individuals of nominate subspecies
guadalupe storm petrel (oceanodroma macrodactyla), 1910s
the guadalupe ruby-crowned kinglet (regulus calendula obscurus) close extinction, if indeed still exists. not observed in 2000 despite thorough searches.

globally extinct plant taxa guadalupe island are:

castilleja guadalupensis
hesperelaea palmeri
pogogyne tenuiflora

and 1 species of plant incertae sedis

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