{"id":11778,"date":"2019-10-03t05:00:58","date_gmt":"2019-10-03t05:00:58","guid":{"rendered":"http:\/\/dpetrov.2create.studio\/planet\/wordpress\/invasive-species-control-in-the-galapagos-scientists-propose-fighting-fire-with-fire\/"},"modified":"2019-10-03t05:00:58","modified_gmt":"2019-10-03t05:00:58","slug":"invasive-species-galapagos-tactics","status":"publish","type":"post","link":"\/\/www.getitdoneaz.com\/story\/invasive-species-galapagos-tactics\/","title":{"rendered":"invasive species control in the gal\u00e1pagos: scientists propose fighting fire with fire"},"content":{"rendered":"
according to the gal\u00e1pagos conservation trust<\/a>, controlling invasive species is one of the biggest problems facing the gal\u00e1pagos islands.<\/p>\n gal\u00e1pagos park guides say that goats were first brought to the islands by fishermen as food reserves in the early 20th century. unexpectedly, goats survived quite well on the islands where they were released. but predators like coyotes and wolves that normally keep goats in check are not found in the gal\u00e1pagos, so the population exploded. <\/p>\n goats became so numerous on isabela and santiago islands that native species like the giant tortoise began to decline because they were outcompeted by goats for food. in 1997, when the goat population on isabela island had reached 100,000, action was finally taken. <\/p>\n we all share a soft spot for ch\u00e8vre and goat yoga. so why did these passive plant-eaters need to be stopped? <\/p>\n the gal\u00e1pagos islands is not only important for its consistent rank among \u201cmust see places before you die\u201d lists, the flora and fauna of the islands is biologically unique. in other words, most of the native species on the islands do not exist anywhere else in the world. in biology, uniqueness is valuable. these islands are as unique as it gets. and once the giant tortoises are wiped out, we cannot bring them back. protection of gal\u00e1pagos giant tortoises and all other unique species on the islands is therefore critical.<\/p>\n to eradicate the goats, park rangers were trained in marksmanship and flown in helicopters low over the islands. goats were shot one by one. eventually, so few goats remained that they became difficult to find in the underbrush. scientists developed a brutally clever strategy to remove those that remained: \u201cjudas goats.\u201d <\/p>\n because goats like to congregate in herds, several females were captured, marked, and sent back into the wild with gps trackers. these marked goats were the judas goats. naturally, these females eventually found and joined existing herds and by doing so, exposed the locations of the remaining goats. <\/p>\n the ingenious solution of judas goats led to one of the most successful invasive species eradications on the islands to date. what makes invasive species control so fascinating is the fact that with each new invasive species, a completely new management plan is needed. <\/p>\n the same level of ingenuity in the goat solution is needed to overcome the intricacies of each new invasive situation. it is impossible to predict the downstream result of every action, so creative problem-solving along the way is essential. <\/p>\n as with goats, black rats were introduced by mariners long ago. black rats prey on the eggs of native birds and reptiles. as explained by park guide anah\u00ed concari, \u201cproject pinz\u00f3n\u201d was the park\u2019s response to native species population declines from black rat predation on pinz\u00f3n island. <\/p>\n in 2012, helicopters were used to drop rodenticide in a grid pattern across the island. it was quickly discovered that lava lizards, which are native to the gal\u00e1pagos, also were eating the rodenticide. though the lava lizards were unaffected by the poison, they stored it in their livers. <\/p>\n which only moved the problem up the food chain. the gal\u00e1pagos hawks that ate these lava lizards were affected by the rodenticide and the hawk population declined. the quick thinking solution was to capture as many remaining hawks as possible and hold them in captivity until the rodenticide concentration in lava lizards dropped to safe levels \u2014 which took about two years. <\/p>\n project pinz\u00f3n ultimately was successful on pinz\u00f3n island, but the increased mortality of gal\u00e1pagos hawks was an unexpected and unfortunate price to pay. <\/p>\n the loss of the hawks demonstrates the risks associated with invasive species control in such delicate, interconnected ecosystems. each situation is unique and the stakes are always incredibly high as there\u2019s always the possibility that a seemingly sound idea will unexpectedly do more harm than good.<\/p>\n when a parasitic fly<\/a> is destroying the populations of 20 species of birds, judas goats and rodenticide will be of no help. unfortunately one such fly is currently terrorizing the gal\u00e1pagos. these flies lay eggs in the nests of birds and their larvae suck the blood from baby birds as soon as they hatch. this gruesome invasive fly has pushed several gal\u00e1pagos finches to the brink of extinction.<\/p>\n according to the charles darwin research station, 20 gal\u00e1pagos bird species are at risk from the fly. because the birds are only preyed on as hatchlings, raising birds in captivity until they are no longer hatchlings protects them from the fly. <\/p>\n the mangroves that these birds nest in are sometimes as tall as 20 meters (a little over 65 feet), so professional tree climbers were hired to remove eggs from nests before they hatch. the birds are reintroduced when they are too big to be preyed on by flies. <\/p>\n this strategy has helped, but it is not scalable. there is not enough space or resources to raise enough of each bird species in captivity. other stop-gap methods involving insecticide have been tested but no one strategy has been effective enough. <\/p>\n park guide concari mentioned a controversial management strategy called biological control that has recently been circulating in the conversation about this parasitic fly. <\/p>\n invasive species like these goats, rats, and flies, are able to take over in the gal\u00e1pagos because their normal predators did not travel with them, and none of the predators that keep these animals in check in their native habitats exist in the gal\u00e1pagos. <\/p>\n biological control involves locating a predator or pathogen that checks an invasive in its native habitat and introducing it into the non-native habitat in which it currently lives. in other words, scientists want to introduce another introduced species to deal with a previously introduced species. (got that?) according to information provided by gal\u00e1pagos national park guides, there are already more introduced species on the islands than there are native species. could purposefully introducing more really be worth it?<\/p>\n the strategy of biological control is incredibly risky and still controversial. when the conversation shifts to invasive plants however, biological control does not seem as far fetched. though goats, rats, and flies may seem challenging to eradicate, invasive plants are in fact much more difficult. <\/p>\n