Endemic Galapagos Tree Daisy Scalesia pedunculata Threatened by Competition with Nonnative Blackberry Rubus niveus

There is a debate whether invasive plants can induce extinction debt in native flora that is not immediately obvious. Competitive effects of invasions and how competition causes native biodiversity loss are complicated to evaluate. Experi-mental removal or introduction bears the most promise of demonstrating native species displacement mechanics. Over an eight- year period, we followed plots in the only remaining Scalesia pedunculata forest on Santa Cruz Island, Galapagos, where invading Rubus niveus was either removed or retained. Demographic param-eters and total recruitment failure in the presence of R. niveus suggest that S. pedun-culata may face local extinction in two decades without invasion management

Eat and be eaten : trophic interactions of the introduced frog Scinax quinquefasciatus in anthropogenic environments in Galápagos

While the Galapagos Archipelago is known for its endemic flora and fauna, many introduced species have also become naturalised there, especially on the human-inhabited islands. The only amphibian species known to have established on the islands, the Fowler's snouted treefrog (Scinar quinquefasciatus), is thought to have arrived about two decades ago. Since then, this treefrog has substantially extended its range to the islands of Santa Cruz and Isabela. Our study explores the potential influence of this introduced amphibian on native trophic systems on Santa Cruz and identifies potential antagonists likely to control larval frog populations. To understand the impact of S. quinquefasciaites as a predator of local invertebrate fauna, we performed a stomach-content analysis of 228 preserved adult specimens from seven different localities on Santa Cruz. Of the 11 macroinvertebrate orders recorded, Lepidoptera constituted more than 60% of the contents. We also identified active predators of S. quinquefasciazus tadpoles: larvae of the endemic diving beetle (Thermonectus basillarus galapagoensis). To determine the efficiency of this predator, we conducted predator-prey experiments in ex situ conditions. Tadpole predation was highest after first exposure to the predator and significantly decreased over time. Our experimental results demonstrate that although T. b. galapagoensis larvae are effective tadpole predators, their feeding saturation rates are likely inadequate for frog population control. Our findings provide the first baseline data necessary to make informed ecological impact assessments and monitoring schemes on Santa Cruz for this introduced treefrog

Limited natural regeneration of unique Scalesia forest following invasive plant removal in Galapagos

More than 60% of the flora of the Galapagos Islands is introduced and some of these species have become invasive, severely altering ecosystems. An example of an affected ecosystem is the Scalesia forest, originally dominated by the endemic giant daisy tree Scalesia pedunculata (Asteraceae). The remnant patches of this unique forest are increasingly being invaded by introduced plants, mainly by Rubus niveus (blackberry, Rosaceae). To help large-scale restoration of this ecologically important forest, we seek to better understand the natural regeneration of S. pedunculata after invasive plant control. We monitored naturally recruited S. pedunculata saplings and young trees over five years in an area where invasive plant species are continuously being removed by manual means. We measured survival, height and growth of S. pedunculata saplings and young trees along permanent transects. Percent cover of surrounding plant species and of canopy shade directly above each S. pedunculata individual were determined, as well as distance to the next mature S. pedunculata tree. We identified potential factors influencing initial sapling survival and growth by applying generalized linear models. Results showed a rapid growth of saplings and young trees of up to 0.45 cm per day and a high mortality rate, as is typical for pioneer species like S. pedunculata. Sapling survival, growth and mortality seemed to be influenced by light availability, surrounding vegetation and distance to the next adult S. pedunculata tree. We concluded that natural regeneration of S. pedunculata was high only five months after the last herbicide application but that 95% of these recruits had died over the 5-year period. Further studies are needed to corroborate whether the number of surviving trees is sufficient to replace the aging adult trees and this way maintain remnants of the Scalesia forest. Urgent action is needed to help improve future restoration strategies to prevent further degradation of this rapidly shrinking threatened forest ecosystem

ED011. Levantamiento de línea base de la diversidad de insectos en 40 fincas en Santa Cruz, Galápagos

Agricultural production in Galapagos began in the early 20th century on the 4 inhabited islands. Currently, very little is known about the number, abundance and distribution of insect and plant species in the agricultural area. Information on the presence of invasive species and their impacts on agricultural production is also limited. To ensure the sustainability of human life and the conservation of Galapagos species, it is essential to know the terrestrial biodiversity and the interactions with socio-ecological systems. To fill this information gap, a baseline of insects was established on 40 farms on Santa Cruz Island. Transects were set up to carry out foliage sweeps with entomological nets and manual collections of insects in the crops of each farm. A total of 16,533 individuals were collected and identified at different taxonomic levels, 10,331 were identified at the species level. 135 species of insects were identified, of which 18.7 % corresponded to endemic, 13.3 % to native, and 46.7 % to introduced species. The species: Bromeloecia wolverinei, Ceraeochrysa everes, Coproica bisphanta, Cosmosciara hartii, Dettopsomyia formosa, Pseudolycoriella cavatica, Psychoda alternata, Pullimosina heteroneura, Zagrammosoma lineaticeps are new records for Galapagos. This information is a useful tool to incorporate into sustainable agricultural practices. For this reason, it is recommended to strengthen the entomological survey system and technical support in the agricultural area of Santa Cruz.La producción agrícola en las Galápagos empezó a principios del siglo XX en las cuatro islas habitadas. Actualmente, se conoce muy poco acerca del número, abundancia y distribución de especies de insectos y plantas en el área agropecuaria. La información sobre la presencia de especies invasoras y sus impactos en la producción agrícola también es escasa. Para asegurar la sostenibilidad de la vida humana y la conservación de las especies de las Galápagos, es fundamental conocer esta biodiversidad terrestre y las interacciones con los sistemas socio-ecológicos. Con el propósito de llenar esta brecha de información, se levantó una línea base de insectos en 40 fincas de la Isla Santa Cruz. Para esto, se establecieron transectos en los que se realizaron barridos del follaje con redes entomológicas y colectas manuales de insectos en los cultivos de cada finca. Se colectaron e identificaron a diferentes niveles taxonómicos 16 533 individuos y de estos, 10 331 fueron identificados a nivel de especie. Se identificaron 135 especies de insectos, de estas el 18,7 % corresponde a insectos endémicos, el 13,3 % a nativos, y el 46,7 % a introducidos. Las especies: Bromeloecia wolverinei, Ceraeochrysa everes, Coproica bisphanta, Cosmosciara hartii, Dettopsomyia formosa, Pseudolycoriella cavatica, Psychoda alternata, Pullimosina heteroneura, Zagrammosoma lineaticeps son nuevos registros para Galápagos. Esta información constituye una herramienta útil a la hora de incorporar prácticas agrícolas sostenibles. Por esto, se recomienda reforzar el sistema de vigilancia entomológica y acompañamiento técnico en la zona agropecuaria de Santa Cruz

Biological invasions in World Heritage Sites: current status and a proposed monitoring and reporting framework

UNESCO World Heritage Sites (WHS) are areas of outstanding universal value and conservation importance. They are, however, threatened by a variety of global change drivers, including biological invasions. We assessed the current status of biological invasions and their management in 241 natural and mixed WHS globally by reviewing documents collated by UNESCO and IUCN. We found that reports on the status of biological invasions in WHS were often irregular or inconsistent. Therefore, while some reports were very informative, they were hard to compare because no systematic method of reporting was followed. Our review revealed that almost 300 different invasive alien species (IAS) were considered as a threat to just over half of all WHS. Information on IAS management undertaken in WHS was available for fewer than half of the sites that listed IAS as a threat. There is clearly a need for an improved monitoring and reporting system for biological invasions in WHS and likely the same for other protected areas globally. To address this issue, we developed a new framework to guide monitoring and reporting of IAS in protected areas building on globally accepted standards for IAS assessments, and tested it on seven WHS. The framework requires the collation of information and reporting on pathways, alien species presence, impacts, and management, the estimation of future threats and management needs, assessments of knowledge and gaps, and, using all of this information allows for an overall threat score to be assigned to the protected area. This new framework should help to improve monitoring of IAS in protected areas moving forward

Endemic species predation by the introduced smooth-billed ani in Galápagos

Funder: International Community FoundationFunder: Christ's College, University of Cambridge; doi: http://dx.doi.org/10.13039/501100000590Abstract: 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

Invasive Blackberry Outcompetes the Endemic Galapagos Tree Daisy Scalesia pedunculata

Island florae are under threat from habitat loss and competition with introduced species worldwide. In the Galapagos Islands, the endemic tree daisy Scalesia pedunculata (Asteraceae) is the dominant tree in the cloud forest of Santa Cruz Island but suffers from competition with the invasive blackberry Rubus niveus. At the site Los Gemelos, a S. pedunculata population was monitored from 2014 to 2021 following mechanical and chemical removal of R. niveus from 17 plots and compared with 17 additional plots where R. niveus remained. The aim of this study was to evaluate the impacts of the R. niveus invasion on S. pedunculata by characterizing the effects of R. niveus removal. Parameters measured in S. pedunculata were diameter at breast height (DBH, from which annual growth rates were determined), total height, survival of individual plants, and recruitment. In the presence of R. niveus, S. pedunculata trees had smaller DBH stems and shorter asymptotic maximum heights, growth rates declined for thin trees, the mortality of larger trees was elevated, and S. pedunculata recruitment was absent. R. niveus removal resulted in DBH-ratios of S. pedunculata more frequently meeting our threshold for fast growth (1.2), trees growing significantly thicker and taller, annual mortality being lower (12.5% vs. 16.2% per year), and recruitment being successful. In the presence of R. niveus, lower survival, growth, and absent recruitment suggested that S. pedunculata could reach quasi-extinction in ~20 years. Swift and decisive management action is needed to prevent the Scalesia forest on Santa Cruz Island from disappearing in less than two decades

The Importance of Very-High-Resolution Imagery to Map Invasive Plant Species: Evidence from Galapagos

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

The Importance of Very-High-Resolution Imagery to Map Invasive Plant Species: Evidence from Galapagos

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

Eat and be eaten: trophic interactions of the introduced frog Scinax quinquefasciatus in anthropogenic environments in Galápagos

While the Galápagos Archipelago is known for its endemic flora and fauna, many introduced species have also become naturalised there, especially on the human-inhabited islands. The only amphibian species known to have established on the islands, the Fowler’s snouted treefrog (Scinax quinquefasciatus), is thought to have arrived about two decades ago. Since then, this treefrog has substantially extended its range to the islands of Santa Cruz and Isabela. Our study explores the potential influence of this introduced amphibian on native trophic systems on Santa Cruz and identifies potential antagonists likely to control larval frog populations. To understand the impact of S. quinquefasciatus as a predator of local invertebrate fauna, we performed a stomach-content analysis of 228 preserved adult specimens from seven different localities on Santa Cruz. Of the 11 macroinvertebrate orders recorded, Lepidoptera constituted more than 60% of the contents. We also identified active predators of S. quinquefasciatus tadpoles: larvae of the endemic diving beetle (Thermonectus basillarus galapagoensis). To determine the efficiency of this predator, we conducted predator-prey experiments in ex situ conditions. Tadpole predation was highest after first exposure to the predator and significantly decreased over time. Our experimental results demonstrate that although T. b. galapagoensis larvae are effective tadpole predators, their feeding saturation rates are likely inadequate for frog population control. Our findings provide the first baseline data necessary to make informed ecological impact assessments and monitoring schemes on Santa Cruz for this introduced treefrog