Invasive Mammals of the Pacific Completed
The terrestrial biota of the Central Pacific is primarily defined by its degree of isolation. At the center lies the Hawaiian Archipelago, which is more than 3,200 km from any continental land mass. After tens of millions of years of evolutionary isolation from all mammals except bats, islands of the Central Pacific were quite suddenly besieged by a number of alien rodents, carnivores and both large and small herbivores. The first mammals were introduced by early canoe voyagers of the Pacific more than 1,000 years ago. The discovery of the Hawaiian Islands by Cook in 1778, like many other islands of the Pacific, marked the second wave of introductions of many hoofed animals for beasts of burden, milk, hides and meat as well as small predators to keep an assortment of stowaway rodents at bay.
Overview:
The terrestrial biota of the Central Pacific is primarily defined by its degree of isolation. At the center lies the Hawaiian Archipelago, which is more than 3,200 km from any continental land mass. After tens of millions of years of evolutionary isolation from all mammals except bats, islands of the Central Pacific were quite suddenly besieged by a number of alien rodents, carnivores and both large and small herbivores. The first mammals were introduced by early canoe voyagers of the Pacific more than 1,000 years ago. The discovery of the Hawaiian Islands by Cook in 1778, like many other islands of the Pacific, marked the second wave of introductions of many hoofed animals for beasts of burden, milk, hides and meat as well as small predators to keep an assortment of stowaway rodents at bay.
Rapid ecological degradation ensued and whole groups of endemic plants and animals suffered extinctions, including virtually all flightless birds, and roughly nine percent of all Hawaiian flora. After a century of settlement by westerners, the concept of eradicating non-native species came about as a solution to primarily agricultural, public health, or economic problems, and only more recently to solve ecological problems. Reversing the devastating effects of alien mammals has proven to be difficult, but limited successes have resulted in the dramatic recovery of native biota.
Mammals General Overview
Most of the isolated islands of the Pacific existed for tens of millions of years in the absence of terrestrial mammals except for bats, which were able to fly over vast oceans and establish themselves. The first human colonists of these islands brought with them domestic pigs (Sus scrofa) from island southeast Asia and Polynesian rats (Rattus exulans). European colonists brought an assortment of other mammals with them nearly 1,000 years later, including domestic goats (Capra hircus), sheep (Ovis aries), cattle (Bos taurus), other types of wild and domestic pigs, cats (Felis catus), rabbits (Oryctolagus cuniculus), rats (R. rattus and R. norvegicus), and mice (Mus musculus). In the absence of natural predators and competitors, these species became abundant on nearly every island, which caused rapid ecological degradation. Native plants of the islands were poorly defended against the newly established herbivores, and native wildlife were naïve to tree-climbing predators with teeth. Species which had never been previously domesticated such as axis deer (Axis axis), European mouflon sheep (O. musimon), and mongooses (Herpestes javanicus) were brought to the islands later and proved to be particularly challenging to manage. Diseases associated with introduced mammals such as toxoplasmosis (Toxoplasma gondii), bovine tuberculosis (Mycobacterium bovis), and bubonic plague (Yersinia pestis) have all caused major problems for wildlife, livestock, and human health in Hawai‘i. Invasive mammals have caused the decline and extinction of numerous native plants and animals, but researchers and land managers have developed progressively more effective strategies for managing these species, allowing the recovery and restoration of native species in increasingly larger natural areas.
Small Mammal/Toxoplasmosis Overview
Many factors have contributed to the decline and extinction of birds in Hawai‘i, not the least of which has been introduced mammalian predators like rats, mongooses, and cats. These predators take eggs, kill nestlings, or nesting adults, but are also sources of diseases that kill birds. One such disease known as toxoplasmosis can cause severe developmental disabilities and occasional mortality in humans but can also have lethal consequences for marine mammals. The infectious agent of the disease, Toxoplasma gondii, is a protozoan, a single-celled organism which behaves like an animal. It is considered a parasite, causing infection directly rather than by producing toxins. It is a zoonosis because it is a disease of animals that can also be transmitted to humans. Only cats –regardless of whether they are domestic or wild species– can support sexual reproduction of this parasite, and thereby serve as the definitive host of the disease. Any other warm-blooded animal, most commonly rodents, can also carry the parasite but can only serve as an intermediate host. Intermediate hosts of the parasite and may sometimes be consumed by people, leading to infection. Known intermediate hosts include feral pigs (Sus scrofa) and mouflon sheep (Ovis musimon), both popular game mammals in Hawai‘i. Birds can also be intermediate hosts, and populations that have been infected and killed by T. gondii include the critically endangered ‘Alalā (Corvus hawaiiensis), the endangered Nēnē (Branta sandvicensis), Red-footed Booby (Sula sula), and Erckel’s Francolin (Pternistis erckelii), a common gamebird. Flowing water may transport T. gondii oocysts –hardy, thick-walled, environmentally resistant spores– in runoff from land to streams and then into marine environments. Thus, T. gondii represents a land-based pathogen that can pollute nearshore marine ecosystems and infect a wide variety of animals in this environment including whales, seals dolphins, and sea otters. The leading cause of death of the endangered Hawaiian monk seal (Monachus schauinslandi) is now known to be T. gondii infection. Many aspects of T. gondii are poorly understood, but current research may soon lead to more effective management strategies to protect native wildlife from both toxoplasmosis and predation.
Below are publications associated with this project.
Is the model a misfit in Hawaii? The North American model in our most recent state
By land and by sea: The widespread threat of feral cats on Hawaiian wildlife
Sheep vs. Palila on Mauna Kea: after 200 years of damage, can these native birds recover?
Effects of ungulate management on vegetation at Hakalau Forest National Wildlife Refuge, Hawai'i Island
An adaptive strategy for reducing feral cat predation on endangered Hawaiian birds
Home range and movements of feral cats on Mauna Kea, Hawai'i
Wild sheep and deer in Hawai'i: a threat to fragile ecosystems
Using population genetic tools to develop a control strategy for feral cats (Felis catus) in Hawai'i
Evidence of feline immunodeficiency virus, feline leukemia virus, and Toxoplasma gondii in feral cats on Mauna Kea, Hawaii
Efficacy of feral pig removals at Hakalau Forest National Wildlife Refuge
A preliminary assessment of mouflon abundance at the Kahuku Unit of Hawaii Volcanoes National Park
Feral Cats: Too Long a Threat to Hawaiian Wildlife
Below are partners associated with this project.
- Overview
The terrestrial biota of the Central Pacific is primarily defined by its degree of isolation. At the center lies the Hawaiian Archipelago, which is more than 3,200 km from any continental land mass. After tens of millions of years of evolutionary isolation from all mammals except bats, islands of the Central Pacific were quite suddenly besieged by a number of alien rodents, carnivores and both large and small herbivores. The first mammals were introduced by early canoe voyagers of the Pacific more than 1,000 years ago. The discovery of the Hawaiian Islands by Cook in 1778, like many other islands of the Pacific, marked the second wave of introductions of many hoofed animals for beasts of burden, milk, hides and meat as well as small predators to keep an assortment of stowaway rodents at bay.
Overview:
The terrestrial biota of the Central Pacific is primarily defined by its degree of isolation. At the center lies the Hawaiian Archipelago, which is more than 3,200 km from any continental land mass. After tens of millions of years of evolutionary isolation from all mammals except bats, islands of the Central Pacific were quite suddenly besieged by a number of alien rodents, carnivores and both large and small herbivores. The first mammals were introduced by early canoe voyagers of the Pacific more than 1,000 years ago. The discovery of the Hawaiian Islands by Cook in 1778, like many other islands of the Pacific, marked the second wave of introductions of many hoofed animals for beasts of burden, milk, hides and meat as well as small predators to keep an assortment of stowaway rodents at bay.
Rapid ecological degradation ensued and whole groups of endemic plants and animals suffered extinctions, including virtually all flightless birds, and roughly nine percent of all Hawaiian flora. After a century of settlement by westerners, the concept of eradicating non-native species came about as a solution to primarily agricultural, public health, or economic problems, and only more recently to solve ecological problems. Reversing the devastating effects of alien mammals has proven to be difficult, but limited successes have resulted in the dramatic recovery of native biota.
Mammals General Overview
Most of the isolated islands of the Pacific existed for tens of millions of years in the absence of terrestrial mammals except for bats, which were able to fly over vast oceans and establish themselves. The first human colonists of these islands brought with them domestic pigs (Sus scrofa) from island southeast Asia and Polynesian rats (Rattus exulans). European colonists brought an assortment of other mammals with them nearly 1,000 years later, including domestic goats (Capra hircus), sheep (Ovis aries), cattle (Bos taurus), other types of wild and domestic pigs, cats (Felis catus), rabbits (Oryctolagus cuniculus), rats (R. rattus and R. norvegicus), and mice (Mus musculus). In the absence of natural predators and competitors, these species became abundant on nearly every island, which caused rapid ecological degradation. Native plants of the islands were poorly defended against the newly established herbivores, and native wildlife were naïve to tree-climbing predators with teeth. Species which had never been previously domesticated such as axis deer (Axis axis), European mouflon sheep (O. musimon), and mongooses (Herpestes javanicus) were brought to the islands later and proved to be particularly challenging to manage. Diseases associated with introduced mammals such as toxoplasmosis (Toxoplasma gondii), bovine tuberculosis (Mycobacterium bovis), and bubonic plague (Yersinia pestis) have all caused major problems for wildlife, livestock, and human health in Hawai‘i. Invasive mammals have caused the decline and extinction of numerous native plants and animals, but researchers and land managers have developed progressively more effective strategies for managing these species, allowing the recovery and restoration of native species in increasingly larger natural areas.
Small Mammal/Toxoplasmosis Overview
Many factors have contributed to the decline and extinction of birds in Hawai‘i, not the least of which has been introduced mammalian predators like rats, mongooses, and cats. These predators take eggs, kill nestlings, or nesting adults, but are also sources of diseases that kill birds. One such disease known as toxoplasmosis can cause severe developmental disabilities and occasional mortality in humans but can also have lethal consequences for marine mammals. The infectious agent of the disease, Toxoplasma gondii, is a protozoan, a single-celled organism which behaves like an animal. It is considered a parasite, causing infection directly rather than by producing toxins. It is a zoonosis because it is a disease of animals that can also be transmitted to humans. Only cats –regardless of whether they are domestic or wild species– can support sexual reproduction of this parasite, and thereby serve as the definitive host of the disease. Any other warm-blooded animal, most commonly rodents, can also carry the parasite but can only serve as an intermediate host. Intermediate hosts of the parasite and may sometimes be consumed by people, leading to infection. Known intermediate hosts include feral pigs (Sus scrofa) and mouflon sheep (Ovis musimon), both popular game mammals in Hawai‘i. Birds can also be intermediate hosts, and populations that have been infected and killed by T. gondii include the critically endangered ‘Alalā (Corvus hawaiiensis), the endangered Nēnē (Branta sandvicensis), Red-footed Booby (Sula sula), and Erckel’s Francolin (Pternistis erckelii), a common gamebird. Flowing water may transport T. gondii oocysts –hardy, thick-walled, environmentally resistant spores– in runoff from land to streams and then into marine environments. Thus, T. gondii represents a land-based pathogen that can pollute nearshore marine ecosystems and infect a wide variety of animals in this environment including whales, seals dolphins, and sea otters. The leading cause of death of the endangered Hawaiian monk seal (Monachus schauinslandi) is now known to be T. gondii infection. Many aspects of T. gondii are poorly understood, but current research may soon lead to more effective management strategies to protect native wildlife from both toxoplasmosis and predation.
- Publications
Below are publications associated with this project.
Filter Total Items: 37Is the model a misfit in Hawaii? The North American model in our most recent state
No abstract available.AuthorsChristopher A. Lepczyk, Edwin D. Johnson, Steven C. HessBy land and by sea: The widespread threat of feral cats on Hawaiian wildlife
No abstract available.AuthorsSteven C. HessSheep vs. Palila on Mauna Kea: after 200 years of damage, can these native birds recover?
No abstract availableAuthorsSteven C. Hess, Paul C. BankoEffects of ungulate management on vegetation at Hakalau Forest National Wildlife Refuge, Hawai'i Island
We compiled and analysed data from 1987-2004 on vegetation monitoring during feral ungulate management at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai'i All areas in the study had previously been used by ungulates, but cattle (Bos taurus) were removed and feral pig (Sus scrofa) populations were reduced during the study period. We monitored six line-AuthorsS.C. Hess, J.J. Jeffrey, L.W. Pratt, D.L. BallAn adaptive strategy for reducing feral cat predation on endangered Hawaiian birds
Despite the long history of Feral Cats Felis catus in Hawai'i, there has been little research to provide strategies to improve control programmes and reduce depredation on endangered species. Our objective Was to develop a predictive model to determine how landscape features on Mauna Kea, such as habitat, elevation, and proximity to roads, may affect the number of Feral Cats captured at each trap.AuthorsS.C. Hess, P.C. Banko, H. HansenHome range and movements of feral cats on Mauna Kea, Hawai'i
Feral cats Felis catus in dry subalpine woodland of Mauna Kea, Hawai?i, live in low density and exhibit some of the largest reported home ranges in the literature. While 95% fixed kernel home range estimates for three females averaged 772 ha, four males averaged 1 418 ha, and one male maintained a home range of 2 050 ha. Mean daily movement rates between sexes overlapped widely and did not differAuthorsDan M. Goltz, S.C. Hess, K.W. Brinck, P.C. Banko, R.M. DannerWild sheep and deer in Hawai'i: a threat to fragile ecosystems
The unique native flora of the Hawaiian Islands, which evolved in the absence of ungulates (grazing animals), is highly vulnerable to damage by trampling and browsing. Wild ungulates introduced into Hawai'i in the past 150 years, including mouflon, axis deer, and mule deer, have severely harmed the native flora. Control measures used against feral animals do not work as well against these wild aniAuthorsSteven C. HessUsing population genetic tools to develop a control strategy for feral cats (Felis catus) in Hawai'i
Population genetics can provide information about the demographics and dynamics of invasive species that is beneficial for developing effective control strategies. We studied the population genetics of feral cats on Hawai'i Island by microsatellite analysis to evaluate genetic diversity and population structure, assess gene flow and connectivity among three populations, identify potential source pAuthorsH. Hansen, S.C. Hess, D. Cole, P.C. BankoEvidence of feline immunodeficiency virus, feline leukemia virus, and Toxoplasma gondii in feral cats on Mauna Kea, Hawaii
We determined prevalence to feline immunodeficiency virus (FIV) antibodies, feline leukemia virus (FeLV) antigen, and Toxoplasma gondii antibodies in feral cats (Felis catus) on Mauna Kea Hawaii from April 2002 to May 2004. Six of 68 (8.8%) and 11 of 68 (16.2%) cats were antibody positive to FIV and antigen positive for FeLV, respectively; 25 of 67 (37.3%) cats were seropositive to T. gondii. AntiAuthorsR.M. Danner, Dan M. Goltz, S.C. Hess, P.C. BankoEfficacy of feral pig removals at Hakalau Forest National Wildlife Refuge
We compiled and analyzed data from 1987–2004 on feral pig (Sus scrofa) management and monitoring activities at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai`i. These data included annual surveys of feral pig and cattle (Bos taurus) activity, the number of feral ungulates removed from closed management units, age and reproductive status from necropsieAuthorsSteven C. Hess, John J. Jeffrey, Donna Ball, Lev BabichA preliminary assessment of mouflon abundance at the Kahuku Unit of Hawaii Volcanoes National Park
Hawaii Volcanoes National Park (HAVO) recently acquired the 115,653 acre Kahuku Ranch unit adjacent to the existing Mauna Loa section of HAVO. Kahuku contains numerous exceptional natural resources including many federally listed threatened and endangered species. An apparently large and growing population of alien mouflon sheep (Ovis gmelini musimon), however, threatens sensitive native plants anAuthorsSteven C. Hess, Ben Kawakami, David Okita, Keola MedeirosFeral Cats: Too Long a Threat to Hawaiian Wildlife
BACKGROUND Domestic cats (Felis catus) were first brought to Hawai`i aboard sailing ships of European explorers and colonists. The job of these predators was to control mice and rats on the ships during the long voyages. As in other places, cats were taken in and adopted by the families of Hawai`i and soon became household pets known as popoki. But cats have always been very well equipped to liAuthorsSteven C. Hess, Paul C. Banko - Partners
Below are partners associated with this project.