RESUMEN
Conservation grazing uses semi-feral or domesticated herbivores to limit encroachment in open areas and to promote biodiversity. However, we are still unaware of its effects on wild herbivores. This study investigates the influence of herded sheep and goats on red deer (Cervus elaphus) spatial behavior by testing three a-priori hypotheses: (i) red deer are expected to avoid areas used by livestock, as well as adjacent areas, when livestock are present, albeit (ii) red deer increase the use of these areas when sheep and goats are temporarily absent and (iii) there is a time-lagged disruption in red deer spatial behavior when conservation grazing practice ends. Using GPS-telemetry data on red deer from a German heathland area, we modelled their use of areas grazed by sheep and goats, using mixed-effect logistic regression. Additionally, we developed seasonal resource selection functions (use-availability design) to depict habitat selection by red deer before, during, and after conservation grazing. Red deer used areas less during conservation grazing throughout all times of the day and there was no compensatory use during nighttime. This effect mostly persisted within 21 days after conservation grazing. Effects on habitat selection of red deer were detectable up to 3000 meters away from the conservation grazing sites, with no signs of either habituation or adaption. For the first time, we demonstrate that conservation grazing can affect the spatio-temporal behavior of wild herbivores. Our findings are relevant for optimizing landscape and wildlife management when conservation grazing is used in areas where wild herbivores are present.
Asunto(s)
Ciervos , Animales , Biodiversidad , Conservación de los Recursos Naturales , Ecosistema , Cabras , Herbivoria , Ovinos , Conducta EspacialRESUMEN
Seed dispersal critically influences plant community composition and species distributions. Increasingly, human mediated dispersal is acknowledged as important dispersal mechanism, but we are just beginning to understand the different vectors that might play a role. We assessed the role of mountain bikes as potential dispersal vectors and associated social-ecological consequences in areas of conservation concern near Freiburg, Germany. Seed attachment and detachment on a mountain bike were measured experimentally at distances from 0 to 500 m. We assessed effects of seed traits, weather conditions, riding distance and tire combinations using generalized linear mixed effect models. Most seeds detached from the mountain bike within the first 5-20 m. However, a small proportion of seeds remained on tires after 200-500 m. Attachment was higher, and the rate of detachment slower, in semi-wet conditions and lighter seeds travelled farther. Seed dispersal by mountain bikes was moderate compared to other forms of human mediated dispersal. However, we found that lighter seeds could attach to other bike parts and remain there until cleaning which, depending on riders' preferences, might only be after 70 km and in different habitats. Ecological impacts of mountain biking are growing with the popularity of the activity. We demonstrate that mountain bikes are effective seeds dispersers at landscape scales. Thus, management to mitigate their potential to spread non-native species is warranted. We suggest bike cleaning between rides, control of non-native species at trailheads and increased awareness for recreationalists in areas of conservation concern to mitigate the potential negative consequences of seed dispersal.