New study of terrestrial vertebrate fauna in Bosque Pehuén will be key to the conservation of the forests of the Andean Araucanía

Carried out by researchers from the Universidad Católica de Temuco, the study analyzed the population dynamics of the terrestrial vertebrate fauna in Bosque Pehuén, the conservation area of Fundación Mar Adentro.

Puma encontrado. en Bosque Pehuén

A study that lasted over a year and began with the elaboration of a catalog–based on diverse scientific literature related to terrestrial vertebrates (mammals, birds, reptiles and amphibians)–to identify the species that might be found in Bosque Pehuén, a privately protected area (PPA) that protects the headwaters of the Palguín’s watershed. The area covers 882 hectares and its altitude ranges between 860 and 1,400 meters above sea level, which includes a land dominated by secondary forests and mature remnant forests.

The researchers carried out seasonal samplings of terrestrial vertebrates throughout 2021 and early 2022. This allowed the team to put together the first annual faunal inventory of the reserve, which includes essential information for analyzing objects of conservation (OfC) when updating the protected area management plan.

To characterize the populations of wild fauna that were found, the research team analyzed their species richness, relative abundance of species, diversity index, similarity index, species concentration points and potential nesting points for certain studied faunal groups. The inventory was carried out through field records during each of the four seasons of the year through censuses, sightings, visual encounter surveys (VES), indirect methods such as search for animal footprints and signs, and thanks to the data provided by key informants with extensive knowledge of the area.

Main research findings

Imagen de gato guiña

80 species of terrestrial vertebrates were found in Bosque Pehuén, of which 25 correspond to mammals such as the puma (Puma concolor), the güiña (Leopardus guigna) and the culpeo fox (Lycalopex culpaeus); 44 bird species, including birds of prey such as the white-throated hawk (Buteo albigula), the rufous-legged owl (Strix rufipes) and the austral pygmy owl (Glaucidium nana); 4 species of reptiles; and 7 species of native amphibians, including the olive spiny-chest frog (Alsodes verrucosus) and Darwin’s frog (Rhinoderma darwinii), both of which are classified as endangered species by the Ministry of the Environment (D.S. 42/2011 MMA).

According to the inventory, a total of 25 mammal species were recorded, which include both native (15 species) and introduced (10 species) mammals. The highest proportion of species (17 species) was found in a sampling station of Bosque Pehuén that presents areas of transition, that is, an ecotone of forest associated with the edges of the river (wetland) and an ecotone between the grassland and forest, habitats with a great diversity of food and shelter for species. Meanwhile, the presence of invasive exotic species (IES) such as wild boar (Sus scrofa), American mink (Mustela vison), red deer (Cervus elaphus) and others, is attributed to the fact that Bosque Pehuén is close to anthropized areas, with its boundaries very close to private properties with multiple land uses, which also become habitats for these species.

Another highlight of the study were the records of small mammals such as the monito del monte marsupial (Dromiciops gliroides) and the long-tailed pygmy rice rat(Oligoryzomys longicaudatus) . In turn, the camera traps installed in the different sampling stations reported the presence of the culpeo fox, puma and güiña, species that have been classified in threatened species categories of least concern, almost threatened and vulnerable, respectively. They are also included in the Appendix II of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) and its hunting is prohibited throughout the country.

There were also registered 44 species of diurnal and nocturnal birds; 57% of the species that are expected to be found in ecosystems like the ones existing on this PPA. The highest species richness and the largest species abundance were found in the sampling station located in an area covers by an oak, raulí and coihue forest type, which presents two ecotones (forest-wetland and forest-grassland), with a total of 36 species and 139 inventoried individuals.

Regarding the registered birds, 43 species are native species and one was a non-native species–the house sparrow (- Passer domesticus) which was seen during spring. Among the native birds found by the group of researchers they are: the black-crowned night heron (Nycticorax nycticorax), the buff-necked ibis (Theristicus caudatus), the black vulture (Coragyps atratus), the red-backed hawk (Buteo polyosoma), the white-throated hawk (Buteo albigula), the southern crested caracara (Caracara plancus), the chimango caracara (Milvago chimango) and others.

Four species of reptiles were also registered in the inventory, of the 10 total potential species defined in the area’s catalog, among which 3 belong to the genus Liolaemus (L. araucaniensis, L. pictus and L. tenuis) and the other corresponds to the short-tailed snake (Tachymenis chilensis). The presence of the Araucanian lizard (L. araucaniensis) should be highlighted, a species classified as vulnerable and a species of which there are very few records in the Andes of the Biobío and La Araucanía regions of Chile.

Regarding the amphibians, 7 species were registered, in comparison to the 6 potential species defined in the catalog, representing a 116% record with respect to the expected occurrence. This group has high species diversity in a reduced area of Bosque Pehuén, which motivated the research team to add an additional sampling station after the first field trip, entitled Amphibian Sanctuary. The area is covered by an oak-raulí- coihue forest type with a humid undergrowth, where 100% of the inventoried species were found, including the Chiloe Island ground frog (Eupsophus calcaratus), the gray wood frog (Batrachyla leptopus) and Darwin’s frog (Rhinoderma darwinii), among others.

Research relevance

To develop effective conservation initiatives to protect native biodiversity, it is crucial to understand which and how many species can be found in a specific ecosystem, as well as the condition of the habitats where these species develop their life cycles. This way, it’s possible to carry out actions to protect the structure and functioning of these ecosystems. One way to do so, while also generating useful information to make management decisions, is through the establishment a fauna baseline and subsequent monitoring of the populations of inventoried species.

This study has brought knowledge on Bosque Pehuén’s contribution to the conservation of the ecosystems and habitats of the wild fauna communities of terrestrial vertebrates, which are found in fragile areas of the Andean foothills of the Araucanía region. It will make it possible to determine with a higher level of detail the objects of conservation in the PPA, and to identify critical threats to biodiversity and adopt new conservation and restoration strategies to reduce or eradicate priority threats. Together with the permanent wildlife monitoring, it will allow the establishment of a roadmap for Bosque Pehuén that contributes to the maintenance of these ecosystems and the faunal communities that inhabit it.

The Public protected areas of Chile currently are conservation “islands” within a landscape of multiple uses and they are being impacted by various human pressures. Therefore, the country’s protected surface that is inside privately protected areas (which reached 1,669,151 ha in 2013), such as Bosque Pehuén, allows for an ecosystemic connectivity to the landscape while also expanding the range of mobility of wild fauna, especially in highly threatened areas, promoting genetic variability.

It should be noted that this research, entitled “Study of the population dynamics of terrestrial vertebratesin the Bosque Pehuén privately protected area, Araucanía region”, is part of the Collaboration Agreement between Fundación Mar Adentro and Universidad Católica de Temuco. It was carried out by a team of researchers from the Laboratory of Applied Ecology and Biodiversity of the Universidad Católica de Temuco, from the Department of Environmental Sciences of the Faculty of Natural Resources; led by the ecologist Pamela Sánchez, professor and expert in wild fauna Basilio Guiñez, renewable natural resources engineers Sebastián Barra and Lesly Estrada, and the student Constanza Vera.