Long-term monitoring of mammal communities in the Peneda-Gerês National Park using camera trap data

Study Extent

The dataset is obtained from a long-term monitoring campaign that is conducted every year since 2015. Currently, images from 2015 to 2021 are classified, but further data will be included in the future. In 2015 and 2016 camera traps were deployed from April to August and from 2017 to 2019 from May to October. In 2020, because of travel restrictions during the Covid pandemic camera traps could only be deployed in June and were left in the field until May, 2021. Due to theft and malfunction the number of operative cameras ranged from 61 in 2016 to 48 in 2020. Since 2020 cameras remain in the field all year with maintainance and data collection scheduled in May and October.

Sampling

For the study, 64 camera traps (Reconyx Hyperfire HC600, Holmen, WI, USA) were deployed in a 16 km² grid South-West of Castro Laboreiro. They were distributed as uniformly as possible across the different land-use types (e.g. 10% of cameras in land-use types that cover 10% of the area) with one camera per 0.25 ha grid cell (approx. 500 m spacing between each camera). Real locations could deviate by up to 100 meters from the planned locations due to accessibility and placement possibilities. Further, some locations had to be adjusted throughout the years because of changes in the vegetation structure or due to theft, but new locations were within 100 m of the original location and placed in similar habitats. The coordinates in the dataset were rounded to three decimals for safety reasons. The cameras remained active for 24 hours per day and were programmed on motion sensor to take three consecutive pictures each time they were trigged by an animal with no delay after a trigger event. The sensitivity of the sensor was set to high in 2015, 2016 and 2019, medium in 2017 and 2018 and medium/high in 2020 (see eventRemarks). Sampling effort was measured as the number of camera traps multiplied by the number of days they remained active (Rovero et al. 2010).

Quality Control

To ensure using the updated scientific name and common name of species, the taxonomic nomenclature followed the catalogue of life (https://www.catalogueoflife.org/). Additionally, we checked every species in the database of the IUCN Red List of Threatened species (https://www.iucnredlist.org) for their conservation status and populations trends.

Method steps

1. Each image obtained from the camera traps was classified manually. The images were later imported into Agouti (https://www.agouti.eu/) to be made publicly available. There they were automatically grouped into sequences of contiguous images with each sequence representing one distinct occurrence event. The pre-classified observations were linked to the respective sequences using the image name. Starting with the data from 2020, the images were directly imported into Agouti and classified within the software. The dataset was exported from Agouti in Camtrap DP format and manually converted to Darwin Core standard. It is structured as a sample event dataset including the event and the occurrence data and published as a Darwin Core Archive (DwC-A). Here, an event refers to a camera trap deployment at a certain location over a certain amount of time (equivalent to "deployment" in Camtrap DP format) and an occurrence refers to a distinct occurrence event (here: sequence, equivalent to "observation" in Camtrap DP format). The published DwC-A dataset only includes events that contained observations of an animal. As the DwC-A format currently doesn't allow for hierachical datasets with more than two levels, we included the first ten images of each occurrence event as associatedMedia in the occurence table. The original Camtrap DP dataset including also blank and unknown occurrences will be published as supplemental material to this publication and made available through GBIF in the future.

Mammals and birds were identified to the species level where possible.

1. Mammalia
   common name: Mammals rank: class
2. Aves
   common name: Birds rank: class

Castro Laboreiro and Lamas de Mouro, Peneda-Gerês National Park, Portugal.