Gayana

Misinterpretation of historical data for determining past huemul (Hippocamelus bisulcus) distribution and migratory patterns may threaten their conservation: A critique of Flueck et al. (2022)

Paulo Corti — 2023-08-08

Historical accounts documenting the presence of a species, despite several known spatial and temporal weaknesses, are useful to understand distribution patterns, to establish conservation baselines, and to develop effective conservation strategies. An article by Flueck et al. (2022), based on historical records, proposes to reinterpret the past distribution, population dynamics, and migratory behaviour of the huemul (Hippocamelus bisulcus), an endangered deer endemic of the southern Andes. Our analysis of the same historical data revealed a range of questionable interpretations of the sources. Because of this, we argue that the conservation strategies for huemul proposed by Flueck et al. (2022) may be counterproductive and even potentially harmful.

Range extension of the Endangered lizard Pristidactylus volcanensis Lamborot & Díaz, 1987 (Squamata, Leiosauridae): first record in the Yeso River andean sub-basin

Jorge Mella-Romero — 2023-08-08

Herein we describe the record of Gruñidor de El Volcán Pristidactylus volcanensis in a new locality, on the road to Embalse El Yeso, in the Metropolitan region (Chile), which extends its known geographic distribution (with only four previous localities) 5,8 km north. This is the first record of this Endangered species in the Yeso River sub-basin, tributary of the Maipo River.

Distribution extension of Adistemia convexa (Dajoz, 1974) (Coleoptera, Latridiidae) in Chile

Francisco Tello — 2023-08-08

Here we reported the presence of a minute brown scavenger beetles (Coleoptera, Latridiidae), Adistemia convexa (Dajoz, 1974) in an urban forest located at Valdivia city of Chile, collected using tree-trunk flight intercept traps. Based on this finding, the distribution of this genus and species is extended at 900 km towards the south of Chile, expanding the forest association to the Temperate Valdivian Forest.

Observation of the growth of a bifurcated tail in the Chilean Marked Gecko, Garthia gaudichaudii (Squamata, Phyllodactylidae)

Claudio Reyes-Olivares — 2023-08-08

Many lizards (Superorder Lepidosauria) can regenerate their tail after fully or partially autotomizing it. However, abnormalities in regeneration can sometimes occur, such as the growth of one or more additional tails from wounds produced, for example, by incomplete autotomy. In this work, we describe the growth of an additional tail (i.e., bifurcated tail formation) in the endemic Chilean gecko, Garthia gaudichaudii, which reached a total length of 7.1 mm in 48 days of captivity.

A global review of the American mink (Neovison vison) removal techniques – Patagonia as a case study for their potential application

Ronar López — 2023-08-08

American mink (Neovison vison) represents a threat to both biodiversity and economy in various regions of the world, including Patagonia. This invasive species has been successfully removed from many areas of Europe. In Chile and Argentina there have been only patchily distributed attempts of local control to date and large-scale removal has been considered unfeasible. We analyzed available scientific information, to determine best-fit strategies and improved methodologies that increase efficiency (capture per unit of effort) in American mink control. We reviewed published papers about programs that aimed at local control, functional or total eradication of minks in the Web of Science (WoS) database. Based on accessible information, the influence of some field variables on capture efficiency was determined through a General Lineal Model. From 1525 results in the WoS search, 51 papers refer to mink control action carried out in 28 areas of Europe and South America since 1992. Trapping has been the most used and efficient capture method. Short trapping periods that cover larger lineal distances per control program, and the use of attractants, specifically pheromones, have led to improved control efficiency. Chilean, Scottish and English experiences showed among the highest trapping efficiency values. We identify areas of research needed on mink ecology and behavior and trapping techniques that could improve trapping efficiency. A control program that incorporates the outcomes of this data assessment has the potential to improve feral mink removal. But further research is required to ensure that these efficiency measures result in cost-effective control in Patagonia.

Resource selection in colonies of Chinchilla laniger (Rodentia: Chinchillidae) from Las Chinchillas National Reserve (Aucó, Chile)

Víctor Bravo-Naranjo — 2023-08-08

Analizamos los factores del hábitat que influyen en la selección de sitios de la chinchilla costera Chinchilla laniger para el establecimiento de colonias en la Reserva Nacional Las Chinchillas en Aucó, Región de Coquimbo, Chile. Utilizamos modelos lineales generalizados y un diseño de presencia-ausencia con ajuste logístico, considerando la presencia y ausencia de Puya berteroniana, afloramientos rocosos, altitud, pendiente, exposición de la ladera y coberturas tanto vertical como horizontal de la vegetación como variables explicativas. Las variables del modelo que mejor explicarían la presencia de colonias de chinchilla en la Reserva serían la presencia de puya, seguida de la altitud, presencia de afloramientos rocosos y la cobertura vertical de la vegetación. Los resultados indican que cuando P. berteroniana se encuentra presente, la probabilidad de encontrar una colonia de chinchilla es del 97% (IC 95% = 56% – 99%), la que disminuye a 23% (IC 95% = 12% - 39%) cuando esta especie de bromelácea no se encuentra presente en el hábitat. Los resultados sugieren que C. laniger selecciona microhábitats específicos dentro del entorno heterogéneo del paisaje semiárido de la Reserva Nacional Las Chinchillas.

Seasonality in the feeding ecology of Black-necked swans (Cygnus melancoryphus) in a temperate wetland of southern Chile

Cecilia Norambuena — 2023-08-08

The concomitant effects of environmental physical constraints associated with the availability and quality of food will finally affect the energy budget of wild animals. This study aimed to determine the effect of seasonality on water level, behavioural and nutritional status of Black-necked swans inhabit the Budi Lake, Chile. In winter and spring, the water level was recorded using a graduated rod and a time budget of 60 swans/hours was recorded from 8 am to 6 pm using binoculars and the focal method. In order to determine nutritional status a subset of 20 birds were captured and weight, length, wingspan, and tarsal length were measured. Also, blood sample was collected to determine cholesterol, triglycerides, and total proteins plasma concentrations. Budi Lake’s water level increase in winter (111 ± 3 cm vs 54 ± 0.6 cm, P = 0.04). In addition, winter swan population increased significantly the time allocated to foraging at morning, and the proportion of effortful foraging behaviour (37/222 vs 14/185, P = 0.01), assigning less time to resting activities (7 ± 4 % vs 11 ± 2 %, P = 0.05) compared with spring population. Nutritional status was not compromised in swan populations in both seasons. In conclusion, behavioral adjustments allow Black-necked swan populations to maintain an adequate nutritional status despite the increase in water level during winter season.

Range expansion of the screaming cowbird (Molothrus rufoaxillaris) mediated by a new brood parasite-host interaction in central Chile

Vicente Pantoja — 2023-08-08

The Screaming Cowbird (Molothrus rufoaxillaris) is a brood-parasite specialized in parasitizing the Grayish Baywing (Agelaioides badius). Recently, it started to parasite a new host, the Austral Blackbird (Curaeus curaeus), which has driven the expansion of its range to central Chile. However, its actual and potential distribution and the natural history of this interaction are scarcely known. In this note, we describe the distribution, habitat use and phenology of the species in Chile. Additionally, we present data on feeding events of Screaming Cowbird fledglings by Austral Blackbirds. For doing so, we analyzed data from a citizen-science project using Maxent and Random Forest models. We found that the Screaming Cowbird is distributed mainly in urban and agricultural habitats, avoiding native shrublands and forests. The potential distribution is driven by the temperature and the Austral Blackbird distribution. This note confirms the relationship between both species of icterids and gives new insights into how new host-parasite interactions can drive the range expansion of brood parasitic birds.

New records for the pleustonic snails Janthina and Recluzia (Gastropoda: Epitoniidae) for Chile

Marina Fuentes — 2023-08-08

Janthina and Recluzia species are pleustonic snails that feed on cnidarians and can be easily differentiated by their shells, which are of a striking purple to violet-blue hue in Janthina, and whitish to brownish in Recluzia. In the southeastern Pacific off Chile, four of the five extant Janthina species and a single species of Recluzia have been recorded. In this work, we present new records for Janthina janthina (Linnaeus, 1758) for specimens collected at San Felix Island, in the Desventuradas Islands, and for Recluzia lutea (Bennet, 1840) for a specimen collected at Robinson Crusoe Island, in the Juan Fernandez Archipelago. These records fill a gap in the geographical distribution of J. janthina in the southeastern Pacific and extend the distribution of R. lutea in about 3000 km from its previous record at Easter Island, being the most easterly record for the species.

Phase changes between corals in Chinchorro Bank, Mexican Caribbean reef complex

Daniel Torruco — 2023-08-08

Records of the scleractinian and alcyonarian communities in 9 sampling areas of Banco Chinchorro were analyzed in relation to their spatial distribution in two no consecutive years (2013 and 2018). The area similarities comparison was determined by the values of the second order information index. Cluster analysis show strong differences in the spatial structure of the two groups and resulting in different responses to the control forces in the ecosystem. The indicator species of the characteristics of the ecosystem are Mycetophyllia lamarckiana and Muricea muricata for the hard and soft corals respectively; but in general, a change of dominance in the community of corals from scleractinians to octocorals is perceived. The combination and pressures of these forces make the ecosystem more vulnerable to modifications that cannot be reversed later, resulting in permanent unwanted changes or at least a decrease in its capacity to generate ecosystem services. It is necessary to continue documenting these unwanted alterations and transformations to discover causes and, where appropriate, intervene in an active management towards more desired configurations.

Habitat preference and abundance of Coscoroba coscoroba and Cygnus melancoryphus in Petrel wetland (O'Higgins region, Chile): Implications in the conservation

Marcelo Miranda-Cavallieri — 2023-08-08

Wetlands are environments with a high diversity and global importance due to the ecosystem services they provide. In Chile, most wetlands are threatened, including their avifauna, especially the two southern hemisphere swans (Coscoroba coscoroba and Cygnus melancoryphus). Here, we made three years of monitoring of abundance of both species in the Petrel wetland. Our results show that the Petrel wetland is an important site for the conservation of South American swan populations, with an abundance average of 38.5 ± 18.8 individuals of C. coscoroba (peak of 60 ind.) and 11.6 ± 12.4 individuals of C. melancoryphus (peak of 40 ind.). These swan species avoid sites close to urban areas and show a preference for habitats distant from anthropogenic activities. The detection probability of swans was influenced by minimum and maximum temperature and wind speed. The vegetation aquatic and riverine are key variables to the abundance of these swans. Our large monitoring highlights the importance of Petrel wetland for the conservation of southern swans and provide value information about their abundance patterns and the population dynamics of C. coscoroba and C. melancoryphus. These data support the need to develop conservation and management plans for this wetland.

“Rescue”, relocation, and monitoring of translocated fauna in Chile

Fabian M. Jaksic — 2023-08-08