Relationship of Neotropical otter vestiges with environmental and anthropogenic factors

Abstract

The Neotropical otter, Lontra longicaudis (Mustelidae) is a semi-aquatic mustelid that exploits a variety of freshwater habitats. To understand the relative influence of human activities and environmental factors affecting its distribution and habitat use, we conducted systematic, seasonal surveys of otter signs along the middle Guamá River, in Pará state in the eastern Brazilian Amazon. We applied generalized additive models to compare distribution of otters along the river with data collected on environmental factors (landcover type derived from satellite imagery, and in situ measurements of physicochemical water characteristics) and anthropogenic factors (fishing gear in the river and human habitation along the river). Most otter signs (indicators of otter habitat use) occurred along the shoreline of the main river channel during the dry season; we observed fewer signs during peak flow, probably because the shoreline and floodplain are flooded, which hid signs and made access to the floodplain difficult. The best-fit model included variables for proportion of forest, presence of fishing gear and boats, bank steepness, and presence of rock formations and sand banks. Otter occurrence was negatively related to forested area and positively related to the presence of fishing gear and boats. Otters are likely attracted to fish trapped in fishing gear because they can easily predate on the trapped fish.

Habitat selection of Eurasian otters (Lutra lutra) in urban rivers: the effects of urbanization, water quality, and river structure

“…Floating population within a 300-m radius buffer. Direct human activity negatively affects otter activities (Andrade et al 2019).…”

Middle‐out ecology: small carnivores as sentinels of global change

“…Unlike large carnivores, which are absent and unlikely to recover in many systems, Temperate grassland in North America: red foxes Vulpes vulpes and human development (Kellner et al 2020), black-footed ferrets Mustela nigripes and disease (Matchett et al 2010), bobcats Lynx rufus and riparian health (Mosby et al 2012), swift foxes Vulpes velox and land-use change (Butler et al 2021). Tropical forest in South America: margays Leopardus wiedii and anthropogenic disturbance (Horn et al 2020), South American coatis Nasua nasua and habitat fragmentation (Massara et al 2016), Neotropical otters Lontra longicaudis and human impact (Andrade et al 2019), ocelots Leopardus pardalis and forest loss (Cruz et al 2019). Arid savanna in southern Africa: yellow mongooses Cynictis penicillata and bush encroachment (Blaum et al 2007), black-backed jackals Canis mesomelas and disease (Bellan et al 2012), African wild cats Felis silvestris and habitat fragmentation (Le Roux et al 2015), meerkats Suricata suricatta and climate change (van de Ven et al 2020).…”

New records of Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) in El Salvador

“…Lontra longicaudis is classified as Near Threatened by International Union for Conservation of Nature and has been included in Appendix I of the Convention on International Trade in Endangered Species due to illegal hunting for the use of their pelts in some Latin American countries (Parera 1993;Kruuk 2006;Rheingantz and Trinca 2015;de Almeida and Pereira 2017). Furthermore, this species is affected by anthropogenic threats such as habitat fragmentation, frequent road killings, conflicts with artisanal fishing, and pollution of habitat by industrial and urban waste (Reynoso 1997;Rheingantz and Trinca 2015;de Almeida and Pereira 2017;Andrade et al 2019). In El Salvador, L. longicaudis is listed as an endangered species under national legislation (MARN 2015), and its main threats are the contamination of rivers and the drastic reduction of forest cover (MARN 2019).…”