Impacto de animales sinantrópicos sobre el éxito reproductivo del Pilpilén común (Haematopus palliatus) en el Humedal marino de Coihuín y Chamiza, Puerto Montt, Chile.

Abstract

Las amenazas a las aves playeras costeras son un tema relevante debido a que se han visto potenciadas por efectos del cambio global y actividades antrópicas. Dentro de estas últimas, es usual observar tránsito de vehículos, desarrollo costero de tipo inmobiliario, depredación y pisoteo por animales asociados al humano. Uno de los sitios que se ha visto afectado por aquellas actividades es el Humedal marino de Coihuín y Chamiza, ubicado en la Región de los Lagos, Chile. Este sitio posee una vasta zona de humedales altamente dinámicos abarcando 1765 hectáreas y una planicie intermareal de hasta 1 kilómetro en baja mar. Estas características hacen que este sitio sea propicio para la reproducción y descanso de aves, por ello es considerado un Área Importante para la Conservación de las Aves y la Biodiversidad (AICA) por BirdLife International y sitio de la Red Hemisférica de Reservas para Aves Playeras (RHRAP). En el área señalada nidifica el Pilpilén común (Haematopus palliatus), ave clasificada según la UICN como Preocupación Menor (LC) y Casi Amenazada (NT) en Chile, país en el que reside desde el norte hasta la Península de Taitao (Región de Aysén). Se estima que el éxito reproductivo de H. palliatus ha declinado desde el año 2009, por lo cual la presente investigación tuvo por objetivo evaluar el impacto, por medio del uso de monitoreo autónomo mediante cámaras trampa, del humano y las especies de animales sinantrópicos que intervienen en la reproducción de H. palliatus en el Humedal marino de Coihuín y Chamiza.

Threats to coastal shorebirds are relevant because global change and anthropogenic activities have enhanced them. Among the latter, it is common to observe vehicle traffic, coastal real estate development, predation, and trampling by animals associated with humans. One site affected by these activities is the Coihuín and Chamiza marine wetland in Los Lagos Region, Chile. This site has a vast area of highly dynamic wetlands covering 1765 hectares and an intertidal plain of up to 1 kilometer at low tide. These characteristics make this site conducive to breeding and resting birds, which is why it is considered an Important Bird and Biodiversity Area (IBA) by BirdLife International and a site of the Western Hemisphere Shorebird Reserve Network (WHSRN). The nesting area is home to the American Oystercatcher (Haematopus palliatus), a bird classified by the IUCN as Least Concern (LC) and Near Threatened (NT) in Chile, where it resides from the north to the Taitao Peninsula (Aysén Region). It is estimated that the reproductive success of H. palliatus has declined since 2009, so the present research aimed to assess the impact, through autonomous monitoring by camera traps, of synanthropic animal species involved in the reproduction of H. palliatus in the marine wetland of Coihuín and Chamiza. For this purpose, 11 nests were monitored through camera traps installed during the breeding seasons of 2021 and 2022, with an average sampling effort of 209.4 hr/camera. Each nest was characterized, and through monitoring the type of threat and impact on the bird's behavior was identified. We also recorded activities that are typical of the birds' reproductive behavior. We identified eight threats in the vicinity of the nests; according to the total number of photographs of the threats observed 39.2% of them corresponded to Canis lupus familiaris, 20.5% to Homo sapiens, 14.9% to Bos taurus, 14.9% to motorcycles, 6.5% to Lepus europaeus, 1.8% to Equus caballus, 0.9% to rodents and 0.9% to carts. We recorded direct impacts on the nests, such as egg predation in five nests by C. lupus familiaris individuals, one egg crushing by a motorized vehicle, and egg extraction in two nests by humans. In addition, it was possible to see reproductive aspects of H. palliatus, with their main activity being nest visiting (67.3%) mainly during the afternoon, followed by incubation (27.2%), both in a biparental manner. Although the presence of C. lupus familiaris, humans, and motorcycles have a more significant impact on H. palliatus, all the threats observed generate a certain degree of impact and interruption in the reproductive activities necessary to increase the population size of this species; during the monitoring period, there was no reproductive success of H. palliatus in the nests monitored in the Coihuín and Chamiza wetlands.