Bio-Economics of Large-Scale Eradication of Feral Goats From Santiago Island,Galápagos

ABSTRACT Invasive mammals are premier drivers of extinction and ecosystem change, particularly on islands. In the 1960s, conservation practitioners started developing techniques to eradicate invasive mammal populations from islands. Larger and more biologically complex islands are being targeted for restoration worldwide. We conducted a feral goat (Capra hircus) eradication campaign on Santiago Island in the Galápagos archipelago, which was an unprecedented advance in the ability to reverse biodiversity impacts by invasive species. We removed >79,000 goats from Santiago Island (58,465 ha) in <4.5 years, at an approximate cost of US$6.1 million. An eradication ethic combined with a suite of techniques and technologies made eradication possible. A field-based Geographic Information System facilitated an adaptive management strategy, including adjustment and integration of hunting methods. Specialized ground hunting techniques with dogs removed most of the goat population. Aerial hunting by helicopter and Judas goat techniques were also critical. Mata Hari goats, sterilized female Judas goats induced into a long-term estrus, removed males from the remnant feral population at an elevated rate, which likely decreased the length and cost of the eradication campaign. The last 1,000 goats cost US$2.0 million to remove; we spent an additional US$467,064 on monitoring to confirm eradication. Aerial hunting is cost-effective even in countries where labor is inexpensive. Local sociopolitical environments and best practices emerging from large-scale, fast-paced eradications should drive future strategies. For nonnative ungulate eradications, island size is arguably no longer the limiting factor. Future challenges will involve removing invasive mammals from large inhabited islands while increasing cost-effectiveness of removing low-density populations and confirming eradication. Those challenges will require leveraging technology and applying theory from other disciplines, along with conservation practitioners working alongside sociologists and educators.     

The numbers of land birds, waders, sea birds, land Crustacea, and certain insects on the lagoon islands of Aldabra Atoll

A study was made of the determinants of numbers of species of land birds, waders, breeding sea birds, land Crustacea, and insects on 77 of the lagoon islands of Aldabra Atoll in the Western Indian Ocean. By comparison with other studies, number of plant species and the structural complexity of the vegetation are not significantly related to the number of land bird species; log area accounts for 66.5% of the variance in number. Log area is also the most important factor influencing the number oI wader species. The variables considered account for only 36.2% of the variance in breeding sea bird species; this low figure suggests that other factors are of importance. Isolation of an island is the most important of those considered. Nearly half the variance in the number of insects groups is determined by log number of plant species, while the complexity of the vegetation structure is the only significant variable predicting the number of species of land Crustacea. Differences between the findings of this and other studies are attributed to the particular characteristics or the islands and species considered.
Relatively low z values are found (0.205 for land birds, 0.174 for waders, and 0.136 for land Crustacea), suggesting that inter-island distances do not represent great barriers to the species concerned and immigration and extinction rates are probably in equilibrium.     

The Origin and Genetic Status of Insular Caprines in the Eastern Mediterranean: A Case Study of Free-Ranging Goats (Capra aegagrus cretica) on Crete

The history and species status of free-ranging goats inhabiting the Eastern Mediterranean islands is discussed with reference to morphometric, archaeological and genetic findings. A case study on the free-ranging goats on Crete (Capra aegagrus cretica) is presented. The phenotype of the Cretan goat resembles that of the wild bezoar goat (C. aegagrus). However, the mitochondrial DNA of cytochrome b and d-loop sequences shows affinity with domestic goats. It has been suggested that the Cretan goat represents a feral animal that was introduced onto the island during the 6th millennium b.c. as a primitive domestic, and has retained the wild morphotype but has undergone significant genetic change. An alternative explanation, and the one that is proposed here, is that the goat was introduced onto the island in wild form and released as a food source. Subsequent introgressions with domestic animals, especially ewes, have influenced its genotype. These conclusions are applicable to other free-living goats and sheep which inhabit islands in the Eastern Mediterranean.     

Geographic Tools for Eradication Programs of Insular Non-native Mammals

Non-native mammals are major drivers of ecosystem change and biodiversity loss; this is especially apparent on islands. However, techniques exist to remove non-native mammals, providing a powerful conservation tool. Conservation practitioners are now targeting larger islands for restoration. Leveraging existing and developing new techniques and technologies will prove critical to successful eradications on large islands. Using the removal of introduced goats (Capra hircus) from Santiago Island, Galápagos as a case study, we present a suite of Geographic Information System (GIS) tools that aid island conservation actions. GIS tools were incorporated into the three phases of the eradication campaign: planning, hunting, and monitoring. Further, these tools were adopted for three eradication techniques: ground-based hunting, aerial hunting by helicopter, and Judas goats. These geographic approaches provide a foundation for statistical, spatial, and economic analyses that should increase the capability and efficiency of removal campaigns. Given limited conservation funds and the dire status of many insular species, efficiently removing non-native mammals from islands is of paramount global conservation importance.     

Molecular Characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from Goats in the Western Part of India by LSU of Nuclear Ribosomal DNA

The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India.     

A 10-year study of changes in forest vegetation on Silhouette island, Seychelles

A 10 year study of forest communities on Silhouette island, Seychelles demonstrates stability of forest composition in most areas over this time-scale. Areas with heavy invasion by alien species were found to be regenerating, particularly with the rapid loss of Clidemia hirta. This is attributed to the abundance of well-adapted native plants allowing competitive exclusion to take place, throughout competition for light. It was noted that invasive plant species tend to be unstable on the rocky slopes covered by native high forest. A high rate of tree fall and limited seed dispersal may reduce the impact of the invasive tree Paraserianthes falcataria in the future. Other species such as Cinnamomum verum and Psidium cattleianum may persist as major invaders due to wider seed dispersal.     

Understanding Attitudes Toward the Control of Nonnative Wild and Feral Mammals: Similarities and Differences in the Opinions of the General Public,Animal Protectionists,and Conservationists in New Zealand (Aotearoa)

Lethal control is used extensively in New Zealand to control nonnative nonhuman mammals. Respondents were surveyed about 8 mammal groups considered pests and their attitudes toward their control and pest status. They also identified the most appropriate method of control for the 8 different mammals. Information was gathered from 3 groups of respondents: nonhuman animal protectionists, conservationists, and the general public. Conservationists routinely rated all animal groups as more severe pests than the general public or animal protectionists, who provided the lowest scores. Rats, stoats, brushtail possums, and rabbits were identified as the 4 most serious pests by all 3 groups. Conservationists were 5.7 and 2.6 times more likely to prefer a lethal method of control than protectionists and the general public, respectively. For all 3 groups an increase in pest score for a given animal saw a decline in importance placed upon the animal's welfare. This relationship was strong for the general public but weak for conservationists and animal protectionists. Understanding aspects of potentially opposing viewpoints may be invaluable in supporting the development of new welfare-focused control methods.     

Effects of adult chill treatments on mate attracting potential for irradiated Mexican fruit fly males

Mexican fruit flies, Anastrepha ludens (Loew), that are reared, sterilized and released for maintenance of a fly free zone in south Texas and for population eradication in California are routinely chilled for 1 to 2 h to facilitate handling and dispersal. While a number of behavioral, physical and physiological characteristics are routinely monitored as part of a quality control program, the effect of the chilling process on the ability of these males to attract wild females has not been evaluated. Tests were performed to compare the mate attracting effectiveness of mass reared, sterilized, chilled males with sterile males that had not been chilled and with recently colonized males. Tests were performed with two recently colonized strains of females in a large cage and males of the three types in plastic cups set on top of the cage. Controls consisted of empty cups. Results showed no significant differences among the three types of males. In tests with the most recently collected (least laboratory adapted) wild strain of females, the chilled males attracted the most females. Fly age and time of day were both significantly related to total attractiveness of males. Number of females responding to males per day increased over the five-day test period. The time period when female response was greatest was variable among the tests.     

Evidence for Introgressive Hybridization of Captive Markhor (Capra falconeri) with Domestic Goat: Cautions for Reintroduction

Markhors (Capra falconeri) are among the most endangered mammal species, and several conservation measures, including ex situ breeding, are implemented to prevent their extinction. We studied sequence diversity and differentiation of the first hypervariable segment of the mitochondrial DNA control region among C. f. heptneri and C. f. megaceros kept in four zoos in relationship to lineages of other wild and domestic goats, to assess for the first time the level of molecular distinctness and variability among those subspecies, and to check for possible introgression by related Capra taxa, such as domestic goats. Levels of differentiation between some Capra falconeri lineages and modern domestic goats were similar to levels between other wild goat species (i.e., Capra aegagrus, Capra ibex) and domestic goats. Among pure markhor lineages, paraphyly was observed for C. f. heptneri, suggesting occurrence of shared ancestral polymorphism among markhor subspecies and/or ancient or recent gene exchange between subspecies. Interestingly, 35.7% of all studied markhors from three zoos are introgressed by the domestic goat. Furthermore, despite relatively small breeding group sizes, markhors have maintained a relatively high proportion of mtDNA variation within zoo groups. In any case, the existence of markhors introgressed with domestic goat DNA in zoos should be considered when selecting markhors for ex situ breeding programs with the aim of building up a stock for later reintroduction into the wild.     

Impact of the invasive crazy ant Anoplolepis gracilipes on Bird Island, Seychelles

The crazy ant (Anoplolepis gracilipes) invaded Bird island, Seychelles, in the 1980s. In 1997, its range expanded and population densities increased. The impacts of this change were studied in 2001 using a combination of arthropod collecting methods. The ant population excluded larger invertebrates (principally the large ant Odontomachus simillimus and the crabs, principally Ocypode spp.). Cockroaches, however, remained abundant in ant-infested areas and tree-nesting birds (Lesser Noddy Anous tenuirostris) appear to be able to breed successfully in the presence of the crazy ant. The ants are only abundant in areas of deep shade which provide cool nesting areas, yet enabling them to forage in the open when ground temperatures fall. The expansion of the ants was correlated with the regeneration of woodland on the island. Recommendations are made for the management of the woodland which may reduce the impacts of the crazy ant.     

Prospects for Bonobo Insectivory: Lui Kotal, Democratic Republic of Congo

Chimpanzees (Pan troglodytes) are well-known to eat invertebrates, especially social insects, across Africa, but allopatric bonobos (P. paniscus) are not. Bonobo insectivory is sparsely documented and apparently sporadic. However, the availability to bonobos of social insect prey and raw materials with which to make tools to exploit them is unknown. Here, we test a set of hypotheses that relates to questions of presence, abundance, density, and distribution of taxa that Pan consume and of vegetation suitable for making extractive foraging tools. We worked at Lui Kotal, Democratic Republic of Congo, where unprovisioned bonobos live in intact forest, far from villages. We collected insect and fecal specimens, transected for prey and assessed raw materials, and monitored mounds of Macrotermes. All but 1 of the major taxa of relevant termites, ants, and (stinging) honey bees were present. The 3 main taxa of insects that chimpanzees elsewhere eat —Macrotermes (fungus-growing termites), Dorylus (Anomma; army or driver ants), and Apis (honey bees)— were abundant and widespread, and usually at densities exceeding those at well-known chimpanzee study-sites. Similarly, woody and nonwoody vegetation suitable for making fishing probes was common at mounds of Macrotermes. There is no obvious ecological reason why bonobos should not use elementary technology in extractive foraging, e.g., termite-fish, ant-fish, ant-dip, honey-dip, to obtain social insects.     

Impact of the introduced yellow crazy ant Anoplolepis gracilipes on Bird Island, Seychelles

The introduced yellow crazy ant or long-legged ant Anoplolepis gracilipes was first reported in Seychelles in 1969 and now occurs on at least nine islands in the Central Seychelles. We describe the yellow crazy ant's effects on vegetation and invertebrate communities on one of these, Bird Island; in 2000, Anoplolepis (first reported in 1991) occurred there at densities at least 80 times higher than on other islands in the Central Seychelles. They were associated with high densities of coccid scale insects on foliage, especially of the native tree Pisonia grandis, in some instances causing tree death. Yellow crazy ants on Bird Island also significantly affected invertebrate communities on foliage and on the ground, both in terms of taxonomic composition and the density of specific taxa, apparently causing the local exclusion of some invertebrates.     

The Selection of an Isolate of the Hyphomycete Fungus,Metarhizium anisopliae,for Control of Termites in Australia

Ninety-three isolates ofMetarhizium anisopliae,mostly derived from a survey of termite material, were screened for activity againstNasutitermes exitiosusandCoptotermes frenchiorC. acinaciformisusing a grooming assay technique. Twenty-six of the most promising isolates were further evaluated by bioassay againstN. exitiosusandC. acinaciformis.All isolates were pathogenic withCoptotermesspp. being more susceptible thanN. exitiosus.A group of nine isolates, chosen for their level of pathogenicity for one or other genus of termites and to represent a genetically diverse group, was finally compared in a minicolony test using termite colonies in 1 liter jars. The isolate, code-named FI-610 (derived from nest-mound material ofC. lacteusin SE New South Wales), was one of the most effective isolates against termites from both of the two colonies tested. This isolate also grew relatively well on agar plates at 36°C. FI-610 was thus selected for field trials and was found to be effective in killing colonies ofC. acinaciformiswhen 10 g (=3 × 10¹¹conidia) or more of conidial powder was blown into the center of the large mound colonies.     

Issues Concerning the Eradication or Establishment and Biological Control of the Mediterranean Fruit Fly,Ceratitis capitata(Wiedemann) (Diptera: Tephritidae), in California

Classical biological control is suggested as a tool worth developing now for possible future use in the integrated pest management of the Mediterranean fruit fly (Medfly),Ceratitis capitata(Wiedemann), in California. Three factors that impact broadly on developing and implementing such a biological control program are: (1) the question of Medfly establishment, (2) quarantine considerations, and (3) agricultural and urban concerns. Each of these factors and their combined effects must be considered when discussing biological control of Medfly in California as shaped by historical perspectives on Medfly invasions, methods of Medfly eradication, and past biological control efforts against Medfly. We believe that biological control research should play a foundational role in any future Medfly management programs in California. Development of biological control should involve life history studies of Medfly and its natural enemies in their area of endemicity in sub-Saharan, southeast Africa. Medfly has been studied and should continue to be studied in areas it has invaded, because information derived from such studies provides insights into the potential distribution, abundance, and impact of Medfly populations in California. A plan for a biological research program on Medfly and its relatives and a biological control strategy are presented.     

Effect of Two Opiine Parasitoids (Hymenoptera: Braconidae) Introduced for Fruit Fly Control on a Native Hawaiian Tephritid,Trupanea dubautiae(Diptera: Tephritidae)

Diachasmimorpha longicaudata(Ashmead) andPsyttalia fletcheri(Silvestri) are opiine parasitoids introduced into Hawaii for control of the Oriental fruit fly,Bactrocera dorsalis(Hendel) and the melon fly,Bactrocera cucurbitae(Coquillett), respectively. Both species have recently been mass-reared and released for research in augmentative biocontrol programs. Laboratory and field sleeve cage experiments were conducted to investigate the potential impact of mass-producedD. longicaudataandP. fletcherion a native Hawaiian tephritid,Trupanea dubautiae(Bryan), infesting the flowerheads of the native composite shrubDubautia raillardioidesHillebrand. Gravid females ofD. longicaudataandP. fletcheriwere confined with bloomingD. raillardioidesflowerheads infested with late instarT. dubautiae.BothD. longicaudataandP. fletcherilacked positive oviposition responses toT. dubautiaelarvae in infested flowerheads and caused neither parasitism nor mortality to the flies. However, when larvae were removed from the flowerheads and presented in screened dishes containing artificial diet of the parasitoids' normal rearing hosts (B. dorsalisandB. cucurbitae), bothD. longicaudataandP. fletcherireadily oviposited in the test larvae. Oviposition byD. longicaudatadid not significantly affect the percentage pupation ofT. dubautiae,but did reduce the emergence of adult flies. Oviposition byP. fletcherisignificantly reduced both pupation and adult fly emergence. All progeny of both parasitoid species died as eggs or first-instar larvae. Results from our experiments demonstrate that biological control programs targeted against frugivorous tephritid pests byD. longicaudataandP. fletcherihave no harmful impact on flowerhead-infestingT. dubautiae.     

Control of Muscidae on cattle by flucythrinate ear-tags, the behaviour of these flies on cattle and the effects on fly-dislodging behaviour

In two trials using diary heifers, in the south of England, ear-tags, containing flucythrinate, completely controlled Haematobia irritans (L). Musca autumnalis De Geer on the face were reduced by 41% using one tag and by 76% using two tags per heifer. A single ear-tag reduced numbers of Hydrotaea irritans (Fallén) on the body by 90% and on the teats by more than 55%. Other minor pestering flies were similarly controlled. Control was sustained over the entire 14 weeks duration of the trials which effectively encompassed the fly season of the three main pests.Ear-flicks by the heifers were related to dislodging M. autumnalis from the face, and tail flicks to dislodging Hy. irritans from the belly. These are the two commonest species of nuisance flies and are known to carry pathogenic bacteria.A management plan intended to maximise effective use of insecticidal ear-tags while minimising risks of insecticide resistance is described.

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Résumé Des boucles, contenant du flucythrinate, ont protégé totalement des génisses pour la production de lait contre Haematobia irritans L. lors de deux traitements expérimentaux dans le sud de l'Angleterre.Les effectifs de Musca autumnalis De Geer sur la face des génisses ont été réduits de 41% en utilisant un boucles et de 76% en utilisant deux. Un seul boucles réduit les effectifs d'Hydrotaea irritans Fallén de 90% sur le corps et de plus de 55% sur les pis. Les effectifs d'autres mouches nuisibles de moindre intérêt ont été réduits eux aussi. L'efficacité a été maintenue pendant les 14 semaines du traitement ce qui déborde efficacement le période de vol des 3 principales espèces de mouches nuisibles. Les battements d'oreille des génisses sont destinés à chasser M. autumnalis du visage, et les coups de queue à chasser H. irritans du ventre.Ce sont les deux principales espèces de mouches nuisibles connues comme vecteurs de bactéries pathogènes.Un programme est proposé pour optimaliser l'efficacité des boucles, tout en limitant les risques de résistance aux insecticides.

     

Control ofThrips tabaci [Thysanoptera: Thripidae] on glasshouse cucumber using large introductions of predatory mitesAmblyseius barkeri [Acarina: Phytoseiidae]

The phytoseiid miteAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) was used for biological control ofThrips tabaci Lind. in 7 commercial glasshouses with cucumber (a total of 5780 m²). Predatory mites were introduced 3–4 times in densities ranging from 40 to 300/m² at each release. In 6 of the 7 glasshouses, control of thrips was satisfactory throughout the growing season. Thrips densities were kept below 15 individuals per leaf. In 1 glasshouse, thrips damage was seen on the fruits at densities of 25 thrips per leaf, but the thrips population was quickly reduced and remained at low densities for the next 3 months.      

Biological Control of the Cassava Mealybug in Africa: A Review

Among several natural enemies introduced to combat the cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae), the neotropical parasitoid Apoanagyrus (Epidinocarsis) lopezi (Hymenoptera: Encyrtidae) was the most successful. It established in 26 African countries, causing a satisfactory reduction in the population density of P. manihoti in most farmers' fields. Four conclusions concerning the possible application of the research results to other biological control projects are discussed. (1) Foreign exploration was intensive and should be maintained at this level in other projects, if necessary at the cost of other activities. (2) In the controversy about the amount of research results needed before first releases are made, an understanding of the proper role of quarantine is essential. Whereas quarantine (preferably outside the continent) guarantees nonnoxiousness of natural enemies, only research in the experimental release sites can determine whether a given natural enemy will be efficient. It was confirmed that the released exotic insects did not affect the diversity of the indigenous fauna. Modalities used in this project for the execution of releases, i.e., always on request by and in collaboration with national programs, are recommended for adoption in future projects. (3) Laboratory and field studies established the scientific basis for quantifying the impact of the pest insect and its control by A. lopezi. This was expressed as reduction in pest population levels and yield loss and gain in revenue. Behavior of adult females in searching and choosing hosts was identified as a better predictor of efficiency of a species in the field than life table studies under controlled temperatures. (4) It is concluded that biological control is the basis for integrated pest management. Other interventions, such as cultural methods or the use of resistant varieties, need to be in harmony with biological control because the impact of natural enemies cannot usually be manipulated by the farmer. To achieve sustainability, the aim is to optimize tritrophic interactions among the plant, the phytophagous pest organisms, and their natural enemies, rather than to maximize the effect of a single intervention.     

Restoration of Botshol (The Netherlands) by reduction of external nutrient load: recovery of a characean community,dominated by Chara connivens

Till about 1965 a rich characean community occurred in the shallow peat lake Botshol with six species of which the rare Nitellopsis obtusa and Chara major dominated at many sites. In the period 1980–1988 characean biomass strongly decreased and only two species, Chara globularis and C. connivens, remained in small populations at a few localities. Of the macrophyte Najas marina also some small populations remained, while the aquatic moss Fontinalis antipyretica and the filamentous alga Vaucheria dichotoma predominated at many sites. These phenomena may have been due to eutrophication by the input of polluted water. This process of impoverishment was stopped by restoration measures in 1989, resulting in a lower phosphorus concentration (ca 25 µg l^-1) and a higher water transparency. Immediately after these measures the Characeae community increased in abundance and number of species. During the summer of 1990, and especially 1991, a spectacular growth occurred of Chara connivens. C. connivens was often accompanied by C. major. Other species with scattered occurrence were C. aculeolata, C. aspera, C. contraria and C. globularis. The reasons for the shift in dominance from Nitellopsis obtusa to Chara connivens are discussed. From growth experiments evidence was obtained that neither the recent higher chloride level, nor the lowered phosphate concentration were the main factors for the domination of Chara connivens.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.