Invasive species are one of the main threats to biodiversity worldwide, and the Galapagos Islands are no exception. With the need to control many invasive plant species, accurate distribution maps of invasive plant species are crucial for cost-effective management actions. To guide the selection of appropriate multispectral satellite imagery for this, we evaluated the effects that spatial resolution has on the mapping accuracy of the most invasive plant species in Galapagos with different “growth forms”: (1) tall tree: Cuban cedar (Cedrela odorata), (2) medium tree: guava (Psidium guajava), and (3) shrub: blackberry (Rubus niveus). We developed a mapping methodology based on very high resolution (VHR, WorldView-2) imagery and visual interpretation from orthophotos obtained from unmanned aerial vehicles for training and validation. We then compared our VHR mapping results with medium resolution (MR, Landsat) mapping results and calculated the overall accuracy (OA) and Kappa from confusion matrices for each target species and resolution based on the visual interpretation of Google Earth imagery. The results showed that the OA of the maps produced with VHR was significantly higher than the ones produced with MR. The OA was higher for the tall tree growth form, followed by the shrub and the medium tree growth form. Kappa estimates of <0.5 for MR for the medium tree and shrub growth forms demonstrated its unsuitability for accurate mapping. While MR may be sufficient for mapping the tall tree growth form, we concluded that VHR is indispensable for mapping the medium tree and shrub growth forms.

Mosquera, D., B. Fessl, D. Anchundia, E. Heyer, C. Leuba, E. Nemeth, M. L. Rojas, C. Sevilla, and S. Tebbich. 2022. The invasive parasitic fly Philornis downsi is threatening Little Vermilion Flycatchers on the Galápagos Islands. Avian Conservation and Ecology 17(1):6. https://doi.org/10.5751/ACE-02040-170106

Invasive alien species control is recognized worldwide as a priority action to preserve global biodiversity. However, a lack of general life history knowledge for threatened species can impede the effectiveness of conservation actions. Galápagos pink land iguanas (Conolophus marthae) are endemic to Wolf Volcano, Galápagos, Ecuador. These iguanas are threatened by invasive alien species, particularly feral cats, that may affect their small population size. To guarantee the long-term survival of C. marthae, the Galápagos National Park Directorate is considering, along with an ongoing campaign of feral cat control, the implementation of a head-start program. However, the success of this management strategy necessarily relies on the identification of pink iguana nesting grounds, which were still unknown at the onset of this study. We modeled the movement patterns of male and female iguanas during the reproductive season, using location data collected from custom-made remote tracking devices installed on adult pink iguanas in April 2021. We first calculated for each individual the vector of distances from its starting location, which was defined as net displacement. We then used net displacement as the response variable in a generalized additive mixed model with day of the year as the predictor. Based on the hypothesis that males and females may behaviorally differ after mating, we looked for female-specific migratory behavior suggesting females were moving toward nesting areas. The results obtained confirmed our hypothesis, as females exhibited a distinct migratory behavior, reaching a small plateau area inside of Wolf Volcano’s caldera and ca. 400 m below the volcano’s northern rim. Moreover, once inside the caldera, females displayed a more aggregated distribution pattern. The movement data obtained allowed Galápagos National Park rangers to locate individual pink iguana nests and subsequently to sight and collect the first observed hatchlings of the species. This work constitutes a necessary baseline to perform dedicated studies of pink iguana nests and emerging hatchling iguanas, which is an essential step toward the development of an effective head-start program.

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The Galápagos Petrel (Pterodroma phaeopygia) is a long-lived Critically Endangered seabird endemic to the Galápagos Islands and faces severe threats from invasive species, particularly rodents. Until now, evidence of rat predation on Galápagos Petrel nestlings has been largely indirect, inferred from indirect evidence and predator control outcomes. Here, we present the first photographic documentation of a presumed black rat (Rattus rattus) preying on a Galápagos Petrel nestling, captured by a camera trap on private farmland on Santa Cruz Island. The predation event occurred during a period of parental absence, when the nestling was left unattended while adults foraged at sea. Notably, the parent Petrels continued returning to the nest for 91 days following nestling loss, suggesting strong nest fidelity and highlighting potential energetic costs associated with breeding failure. Our findings reveal critical vulnerabilities during the nestling-rearing phase and emphasize the urgent need to enhance rodent control efforts and protect nesting areas, particularly on farmland outside the Galápagos National Park boundaries. We conclude by providing targeted conservation recommendations to mitigate invasive predator impacts and improve breeding success for this emblematic and imperiled seabird.

(1) The importance of social structure and dominance hierarchies in cooperative-breeding species is well-documented, yet the inclusion of these processes in conservation translocation planning remains limited. Here, we empirically measured the social networks of three populations of the endangered Floreana Mockingbird, then used model simulations of different translocation scenarios to test the effects of social disruption on the social networks. (2) We used social network analysis and Exponential Random Graph Models (ERGMs) to characterise dominance hierarchies, group structure, and the consequences of selectively removing individuals from family groups. (3) Dominance hierarchies were strongly transitive, with age emerging as the primary determinant of dominance relationships. Simulated removals demonstrated that the loss of individuals occupying different network positions produced variable levels of social disruption. (4) Although age is the principal driver of antagonistic interactions, network properties such as high betweenness centrality and the presence of a broker (individuals that occupy a strategic position) are also critical considerations for translocation design. Incorporating social network structure into management strategies can minimise group disruption and enhance the success of conservation translocations for endangered cooperative breeders.