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Conservation practices in agricultural landscapes can greatly mitigate biodiversity loss. However, agricultural landscapes are embedded in complex, social-ecological systems and therefore require a strong social-ecological approach for... more
Conservation practices in agricultural landscapes can greatly mitigate biodiversity loss. However, agricultural landscapes are embedded in complex, social-ecological systems and therefore require a strong social-ecological approach for effective conservation measures. The Galapagos Islands are globally recognized for their high levels of biodiversity. Nevertheless, in recent years, Galapagos landbirds have suffered rapid declines, specifically in the agricultural zone. Our study is the first to examine the farmers’ perception of landbirds in the agricultural zone of Santa Cruz, Galapagos Islands. We conducted semi-structured interviews with 38 farmers to characterize the relationship between farmers and landbirds including how landbirds affect farmers and farmers’ perceptions of landbirds. The interviewed farmers managed a diverse array of farm types including coffee in agroforestry settings (23.7%), small-scale fruit and vegetable (60.5%) and livestock production (15.8%). We found that 86.9% of farmers had a positive or neutral perception of birds despite 52.6% of farmers finding finches bothersome. The most common techniques farmers employed to deter birds were putting out food and water, using nets to protect seedbeds and crops and using protective tubes around young plants. Our results suggest a positive potential for future conservation work targeted on farmland biodiversity. Future conservation projects should also address disservices and the mitigation of crop raiding by landbirds, the uninformed use of pesticides and other pest issues such as ants and rats.
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The fly, Philornis downsi Dodge & Aitken, was first collected in 1964 on the Galápagos Islands and is now widespread across the archipelago. Virtually nothing is known about the behaviour and ecology of the fly as well as for the... more
The fly, Philornis downsi Dodge & Aitken, was first collected in 1964 on the Galápagos Islands and is now widespread across the archipelago. Virtually nothing is known about the behaviour and ecology of the fly as well as for the genus in general. Here, we describe all larval instars for the first time, and discuss infection intensity and impacts of parasitism on nestling survival of Darwin's finches. Adult P. downsi are non-parasitic free-living flies, whereas the larvae are obligate blood-feeding parasites on nestling birds. The larvae show a marked shift in their host site specificity--a novel finding for the genus Philornis: the first and early second larval instars live as agents of myiasis in finch nostrils and other tissues, while the older second and third instar larvae reside in the nest material and feed externally on the blood of nestlings, leading to blood losses in nestlings of 18-55%. Pupation occurs in the bottom layer of the nest. The combined effects of tissue damage by the endoparasitic instar larvae and anaemia by nest-dwelling haematophagous instar larvae account for the high nestling mortality (76%) due to Philornis parasitism. This represents the highest mortality by Philornis reported in the literature and emphasizes the extremely serious threat this parasite poses for the endemic passerine fauna of the Galápagos Islands.
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SummaryThe endemic Galapagos MartinProgne modestais a rare species. Population sizes in the past are unknown, but the few reports available suggest that it has become rarer in some sites. To obtain a better understanding of its population... more
SummaryThe endemic Galapagos MartinProgne modestais a rare species. Population sizes in the past are unknown, but the few reports available suggest that it has become rarer in some sites. To obtain a better understanding of its population status, a simultaneous survey was conducted in 2017 around the coastline of 14 islands and 23 islets resulting in sightings of only 26 individuals. A simultaneous survey on Sierra Negra volcano on Isabela Island added five more individuals. However, observations from early expeditions and expeditions since 2015 have shown that the volcanoes of Isabela Island are important feeding areas and probable breeding areas for the Galapagos Martin, but these were largely excluded from the survey in 2017 due to logistical reasons. Historical and recent nesting sites include Tagus Cove on Isabela Island and Daphne Major Island. During our 2017 count, three possible new nesting sites were discovered: Daphne Minor, Santiago and a small crater on Punta Cristóbal on southwestern Isabela Island. From 2015 to 2018, 15 nests were also observed on the cliff in Tagus Cove. Two accessible nests were collected and revealed the first records ofPhilornis downsiin Galapagos Martin nests. The impact of parasitism byP. downsiis unknown but potentially severe. Given the lack of general knowledge about the biology of this species and its apparent low population sizes, further studies are urgently needed.
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The obligate dipterian bird parasite Philornis downsi and the facultative parasitic fly Sarcodexia lambens were, until recently, unknown on the Galápagos archipelago. The first sign of parasitism of P. downsi on Darwin's finches was... more
The obligate dipterian bird parasite Philornis downsi and the facultative parasitic fly Sarcodexia lambens were, until recently, unknown on the Galápagos archipelago. The first sign of parasitism of P. downsi on Darwin's finches was found in 1997. Parasitism data were collected from 177 nests of 12 bird species, including eight endemic species. In this study we examined host specificity, infection prevalence (percentage of infested nests), parasite load per nest and per nestling, and breeding success for two climatically different years, 1998 and 2000. We found Philornis downsi in 97% of the investigated nests, Sarcodexia lambens in 32% of the nests and a still unidentified endoparasitic Muscidae in 87% of the clutches investigated. The first two ectoparasites showed no host preference and were found in the dry deciduous coastal zone as well as in the evergreen moist forest. Parasite load per nest varied through the breeding stages, with no parasites during incubation, but with numbers increasing with nestling development. Parasite load per nest showed little variation, but variation in brood size led to different infestation rates per nestling. Small broods suffered higher parasite loads and higher nestling mortality, thus inducing a possible impact on population dynamics.
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Toxoplasma gondii is a zoonotic intracellular parasite of particular concern in the conservation of wildlife due to its ability to infect all homeotherms and potentially cause acute fatal disease in naive species. In the Galapagos... more
Toxoplasma gondii is a zoonotic intracellular parasite of particular concern in the conservation of wildlife due to its ability to infect all homeotherms and potentially cause acute fatal disease in naive species. In the Galapagos (Ecuador), an archipelago composed of more than a hundred islets and islands, the presence of T. gondii can be attributed to human-introduced domestic cats, but little is known about its transmission in wildlife populations. We compared the prevalence of antibodies against T. gondii in sympatric Galapagos wild bird species that differ in diet and contact with oocyst-contaminated soil to determine the relative importance of trophic habits as an exposure factor. Plasma samples were obtained from 163 land birds inhabiting Santa Cruz, one of the cat-inhabited islands, and from 187 seabirds breeding in cat-free surrounding islands (Daphne Major, North Seymour, and South Plaza). These samples were tested for the presence of T. gondii antibodies using the modifie...
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Conservation practices in agricultural landscapes can greatly mitigate biodiversity loss. However, agricultural landscapes are embedded in complex, social-ecological systems and therefore require a strong social-ecological approach for... more
Conservation practices in agricultural landscapes can greatly mitigate biodiversity loss. However, agricultural landscapes are embedded in complex, social-ecological systems and therefore require a strong social-ecological approach for effective conservation measures. The Galapagos Islands are globally recognized for their high levels of biodiversity. Nevertheless, in recent years, Galapagos landbirds have suffered rapid declines, specifically in the agricultural zone. Our study is the first to examine the farmers’ perception of landbirds in the agricultural zone of Santa Cruz, Galapagos Islands. We conducted semi-structured interviews with 38 farmers to characterize the relationship between farmers and landbirds including how landbirds affect farmers and farmers’ perceptions of landbirds. The interviewed farmers managed a diverse array of farm types including coffee in agroforestry settings (23.7%), small-scale fruit and vegetable (60.5%) and livestock production (15.8%). We found ...
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<jats:p>Emerging pathogens can have devastating effects on naive hosts, but disease outcomes often vary among hosts. Comparing the cellular response of different host species to infection can provide insight into mechanisms of host... more
<jats:p>Emerging pathogens can have devastating effects on naive hosts, but disease outcomes often vary among hosts. Comparing the cellular response of different host species to infection can provide insight into mechanisms of host defense and the basis of host susceptibility to disease. Here, we used RNA-seq to characterize the transcriptomic response of Darwin's finches to avian poxvirus, which is introduced to the Galapagos Islands. We tested whether gene expression differs between infected and uninfected birds, and whether transcriptomic differences were related either to known antiviral mechanisms and/or the co-option of the host cellular environment by the virus. We compared two species, the medium ground finch (Geospiza fortis) and the vegetarian finch (Platyspiza crassirostris), to determine whether related species have similar responses to the same novel pathogen. We found that medium ground finches had a strong transcriptomic response to infection, upregulating genes involved in the innate immune response including interferon production, inflammation, and other immune signaling pathways. In contrast, vegetarian finches had a more limited response to infection. Our results also revealed evidence of viral manipulation of the host's cellular function and metabolism, providing insight into the ways in which poxviruses affect their hosts. Many of the transcriptomic responses to infection mirrored known processes seen in model and in-vitro studies of poxviruses indicating that many pathways of host defense against poxviruses are conserved among vertebrates and present even in hosts without a long evolutionary history with the virus. At the same time, the variation we observed between closely related species indicates that some endemic species of Galapagos finch may be more susceptible to avian pox than others.</jats:p>
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ABSTRACT Previous intensive surveys on Floreana, the smallest inhabited island of the Galápagos archipelago, in 2015 and 2016, produced reliable population estimates for all landbirds but failed to find 4 species that formerly occurred on... more
ABSTRACT Previous intensive surveys on Floreana, the smallest inhabited island of the Galápagos archipelago, in 2015 and 2016, produced reliable population estimates for all landbirds but failed to find 4 species that formerly occurred on the island: Gray Warbler Finch (Certhidea fusca), Vegetarian Finch (Platyspiza crassirostris), Little Vermilion Flycatcher (Pyrocephalus nanus), and Galápagos Rail (Laterallus spilonota). We revisited the island in February 2018 to extend our search to additional areas but again found none of the 4 lost species. As there is no longer any suitable habitat, we are certain that Galápagos Rail is now extinct on Floreana. It is possible that the remaining 3 species still survive in pockets of habitat that have not yet been surveyed. The very distinct subspecies of Gray Warbler-Finch (C. f. ridgwayi) especially merits further investigation.
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Habitat destruction and predation by invasive alien species has led to the disappearance of several island populations of Darwin's finches but to date none of the 13 recognized species have gone extinct. However, driven by rapid... more
Habitat destruction and predation by invasive alien species has led to the disappearance of several island populations of Darwin's finches but to date none of the 13 recognized species have gone extinct. However, driven by rapid economic growth in the Galápagos, the effects of introduced species have accelerated and severely threatened these iconic birds. The critically endangered mangrove finch ( Camarhynchus heliobates ) is now confined to three small mangroves on Isabela Island. During 2006–2009, we assessed its population status and monitored nesting success, both before and after rat poisoning. Population size was estimated at around only 100 birds for the two main breeding sites, with possibly 5–10 birds surviving at a third mangrove. Before rat control, 54 per cent of nests during incubation phase were predated with only 18 per cent of nests producing fledglings. Post-rat control, nest predation during the incubation phase fell to 30 per cent with 37 per cent of nests pro...
Research Interests: Geography, Biology, Ecology, Invasive Species, Ecuador, and 15 moreEndangered Species, Medicine, Biological Sciences, Computer Simulation, Female, Animals, Male, Pest control, Introduced species, Ecosystem, Nesting Behavior, Conservation of Natural Resources, Finch, Finches, and Medical and Health Sciences
The Critically Endangered mangrove finch Cactospiza (=Camarhynchus) heliobates is now confined to Isabela Island in the Galápagos Islands and is exclusively found in mangrove forests. Formerly it occurred also on neighbouring Fernandina... more
The Critically Endangered mangrove finch Cactospiza (=Camarhynchus) heliobates is now confined to Isabela Island in the Galápagos Islands and is exclusively found in mangrove forests. Formerly it occurred also on neighbouring Fernandina Island, but is apparently extinct there. The population size and ecology of the species was relatively unknown until 1994. We conducted surveys, habitat assessments and behavioural observations of the species between 1996 and 2000. Although Isabela Island has approximately 760 ha of mangrove forests, breeding was confirmed at only two sites, comprising 32 ha in total, on the north-western coast. Our estimate of the population in these two areas is 100 individuals. Additionally, 3–5 territories (which probably contained breeding individuals) were discovered on the south-eastern coast. A comparison of habitat parameters showed that tree height and amount of dead wood were significantly higher within than outside territories, and these are therefore lik...
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This study investigates nest defence and fledging success in relation to nest concealment in two closely related, socially monogamous Acrocephalus warblers: the moustached warbler Acrocephalus melanopogon and the reed warbler Acrocephalus... more
This study investigates nest defence and fledging success in relation to nest concealment in two closely related, socially monogamous Acrocephalus warblers: the moustached warbler Acrocephalus melanopogon and the reed warbler Acrocephalus scirpaceus. We test predictions of the nest exposure hypothesis, and propose that nest defence represents dynamic risk assessment as a function of nest concealment and predator type. During the late nestling feeding phase we placed one of three predator types (plastic snake, stuffed stoat, stuffed harrier) at 1 m from the nest. Nest defence was calculated as a composite factor score using: (i) number of alarm calls, (ii) latency to approach, and (iii) minimum distance to approach. In the moustached warbler, nest concealment was negatively associated with predation, whereas no effect was found in the reed warbler. Nest defence differed significantly in relation to the interaction effect between nest concealment and predator type. In both species, ne...
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Emerging pathogens can have devastating effects on naïve hosts, but disease outcomes often vary among hosts. Comparing the cellular response of different host species to infection can provide insight into mechanisms of host defense and... more
Emerging pathogens can have devastating effects on naïve hosts, but disease outcomes often vary among hosts. Comparing the cellular response of different host species to infection can provide insight into mechanisms of host defense and the basis of host susceptibility to disease. Here, we used RNA-seq to characterize the transcriptomic response of Darwin’s finches to avian poxvirus, which is introduced to the Galápagos Islands. We tested whether gene expression differs between infected and uninfected birds, and whether transcriptomic differences were related either to known antiviral mechanisms and/or the co-option of the host cellular environment by the virus. We compared two species, the medium ground finch (Geospiza fortis) and the vegetarian finch (Platyspiza crassirostris), to determine whether related species have similar responses to the same novel pathogen. We found that medium ground finches had a strong transcriptomic response to infection, upregulating genes involved in t...
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The critically endangered mangrove finch is now limited to one small population on the west coast of Isabela Island in the Galápagos, but 100 years ago multiple populations were found on the islands of Isabela and Fernandina. By accessing... more
The critically endangered mangrove finch is now limited to one small population on the west coast of Isabela Island in the Galápagos, but 100 years ago multiple populations were found on the islands of Isabela and Fernandina. By accessing genetic datasets through museum sampling, we are able to put current levels of genetic diversity and hybridization with congenerics into a historical context for enhanced conservation. In this study, we compared neutral genetic diversity of the now extinct Fernandina population to historical and current diversity of the Isabela population using 14 microsatellite markers. We found that current genetic diversity of the last remnant population (~80–100 individuals) is far below levels 100 years ago, with only about half of the allelic diversity retained. Current genetic diversity is close to levels in the Fernandina population that went extinct by the 1970s. Bottleneck analysis did not show a strong signature of recent decline, and instead implies that this species may have consistently had low population sizes with wide fluctuations. Hybridization with congeneric woodpecker finches was found in the modern Isabela population, implying that some individuals within the few remaining breeding pairs are finding mates with woodpecker finches. Within the context of historical low population sizes and wide fluctuations, current conservation efforts may help the mangrove finch face current extinction threats and avoid the fate of the Fernandina population. However, this historically small lineage will likely continue to face challenges associated with small specialist species surrounded by a widely-distributed sister lineage producing viable hybrids.
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The Avian Vampire Fly, Philornis downsi, has invaded the Galapagos Islands, where it causes high mortality of endemic and native landbird species, including most species of Darwin’s finches. Control methods are under development, but key... more
The Avian Vampire Fly, Philornis downsi, has invaded the Galapagos Islands, where it causes high mortality of endemic and native landbird species, including most species of Darwin’s finches. Control methods are under development, but key information is missing about the reproductive biology of P. downsi and the behavior of flies in and near nests of their hosts. We used external and internal nest cameras to record the behavior of P. downsi adults within and outside nests of the Galapagos Flycatcher, Myiarchus magnirostris, throughout all stages of the nesting cycle. These recordings showed that P. downsi visited flycatcher nests throughout the day with higher fly activity during the nestling phase during vespertine hours. The observations also revealed that multiple P. downsi individuals can visit nests concurrently, and that there are some interactions among these flies within the nest. Fly visitation to nests occurred significantly more often while parent birds were away from the ...
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The introduced smooth-billed ani Crotophaga ani has become widespread across the Galápagos archipelago in the past half-century. It is known to predate upon a range of native and endemic species, and is a potential vector for the spread... more
The introduced smooth-billed ani Crotophaga ani has become widespread across the Galápagos archipelago in the past half-century. It is known to predate upon a range of native and endemic species, and is a potential vector for the spread of invasive plants and parasites. Here we report previously undocumented examples of smooth-billed ani predation in Galápagos, including that of an endemic racer snake and a scorpion. We highlight the possibility of smooth-billed anis having a serious impact on the endemic Galápagos carpenter bee, a major pollinator, as well as native and endemic Lepidopterans and other invertebrates. In addition, we report smooth-billed ani predation of other introduced species and note the importance of further research on the wide-scale impacts of smooth-billed anis in Galápagos and their role within the archipelago’s ecological networks.
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Aichi Target 12 of the Convention on Biological Diversity (CBD) aims to ‘prevent extinctions of known threatened species’. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal... more
Aichi Target 12 of the Convention on Biological Diversity (CBD) aims to ‘prevent extinctions of known threatened species’. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993 - 2020 (the lifetime of the CBD) and 2010 - 2020 (the timing of Aichi Target 12). We found that conservation prevented 21–32 bird and 7–16 mammal extinctions since 1993, and 9–18 bird and 2–7 mammal extinctions since 2010. Many remain highly threatened, and may still become extinct in the near future. Nonetheless, given that ten bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9–4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions.
Summary The endemic Galapagos Martin Progne modesta is a rare species. Population sizes in the past are unknown, but the few reports available suggest that it has become rarer in some sites. To obtain a better understanding of its... more
Summary The endemic Galapagos Martin Progne modesta is a rare species. Population sizes in the past are unknown, but the few reports available suggest that it has become rarer in some sites. To obtain a better understanding of its population status, a simultaneous survey was conducted in 2017 around the coastline of 14 islands and 23 islets resulting in sightings of only 26 individuals. A simultaneous survey on Sierra Negra volcano on Isabela Island added five more individuals. However, observations from early expeditions and expeditions since 2015 have shown that the volcanoes of Isabela Island are important feeding areas and probable breeding areas for the Galapagos Martin, but these were largely excluded from the survey in 2017 due to logistical reasons. Historical and recent nesting sites include Tagus Cove on Isabela Island and Daphne Major Island. During our 2017 count, three possible new nesting sites were discovered: Daphne Minor, Santiago and a small crater on Punta Cristób...
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SummaryWe documented the consequences of large-scale habitat loss on a community of Galápagos native bird species on San Cristóbal island, based on point counts conducted between 2010 and 2017. Surprisingly, despite considerable habitat... more
SummaryWe documented the consequences of large-scale habitat loss on a community of Galápagos native bird species on San Cristóbal island, based on point counts conducted between 2010 and 2017. Surprisingly, despite considerable habitat change and a variety of other threats, the landbirds of San Cristóbal have fared much better than on the neighbouring islands Floreana or Santa Cruz. While two species went extinct very soon after human colonisation, the majority have adapted well to subsequent vegetation change and habitat loss. The endemic San Cristóbal Mockingbird Mimus melanotis is more widespread than previously thought and its population seems to be stable since the 1980s. We thus propose a change in IUCN classification from ‘Endangered’ to ‘Near threatened’. We present evidence gained by interviewing locals which suggests that a small population of the Least Vermilion Flycatcher Pyrocephalus dubius, classified as ‘Extinct’ by BirdLife International, may have persisted until ve...
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El Pinzón de Manglar Camarhynchus heliobates es la especie más rara del grupo de los pinzones de Darwin, y su distribución está restringida a los manglares de la costa de Isabela. Aproximadamente 100 individuos sobreviven y están... more
El Pinzón de Manglar Camarhynchus heliobates es la especie más rara del grupo de los pinzones de Darwin, y su distribución está restringida a los manglares de la costa de Isabela. Aproximadamente 100 individuos sobreviven y están amenazados principalmente por la depredación de la rata introducida Rattus rattus y por el parasitismo de la mosca Philornis downsi. Un amplio programa de conservación se inició en 2006 con el fin de estudiar las aves sobrevivientes, reducir sus amenazas y restaurar la especie en sitios históricos donde anteriormente se la registró. Un número creciente de pinzones en los sitios donde actualmente existe significará mayores probabilidades de dispersión a los sitios históricos. La identificación correcta es necesaria para seguir y monitorear la dispersión de las aves. Esta publicación pretende ayudar a la identificación de la especie y da pautas para distinguirla del Pinzón Carpintero Camarhynchus pallidus, una especie estrechamente emparentada al Pinzón de Ma...
Birds are characterized by a constant body temperature, a pulmonary respiratory system, beaks, bodies covered in feathers, two legs, and two wings. Their reproduction is oviparous.Of the 178 species recorded in Galapagos, 56 are endemic... more
Birds are characterized by a constant body temperature, a pulmonary respiratory system, beaks, bodies covered in feathers, two legs, and two wings. Their reproduction is oviparous.Of the 178 species recorded in Galapagos, 56 are endemic and native. At present, no birds are known to be extinct in the Archipelago, but extinctions have occurred locally on some islands. For marine species distribution data cited in the CDF Galapagos Checklists refer to the five main bioregions of the archipelago (Far Northern, Northern, Western, South Eastern and the Elithabeth Bay Bioregion). For the terrestrial species the more than 120 islands, islets and small rocks have been aggregated into Islands Groups, thus, for example, the island group "Santa Cruz" includes smaller islands like Santa Fé, Plaza Norte, Plaza Sur, Baltra, Daphne Mayor, Daphne Minor, and others. Please be aware that the distribution data presented here is automatically generated from specimen records and does not always...