Alpine ungulate movement: Quantification of spatiotemporal environmental energetics and social interaction

Abstract

Species movement, an animal’s ability to change its location, is a fundamental property of life, and animals have diverse physical and behavioural attributes that are believed to enhance efficient travel and optimization of resources. Quantifying movement energetics and returns to examine these ideas over relevant time- and space scales is, however, problematic. In this thesis, I set out to develop and use advanced biologging tag technology to determine a second by second account of the behaviour and location of tagged animals to unveil where and when key behaviours are occurring, to answer key questions about feeding and social behaviour, allocation in space and the energetic costs associated with different movement decisions. Specifically, I used accelerometers, magnetometers, temperature and pressure sensors with GPS units in animal-attached loggers to examine key questions linking movement, energetics and feeding and aggressive behaviours in 3 wild- and 3 domestic ungulate species in mountainous landscapes in the French Alps, monitored for periods between 30 and 200 days. To obtain high-frequency data using electronic devices for long periods, I had to first design new housings to attach safely the loggers to the animals and develop methods for weather proofing the loggers. I designed, using CAD-designa and 3D printing, different housing types and used ‘Guronic’ resin to shockproof and waterproof circuit boards. This allowed me to obtain logging data for up to 200 days. To give a location per second but stay within ethical weight restrictions, the dead-reckoning method to reconstruct fine-scale movements between low resolution GPS fixes was adopted. To improve the accuracy of dead-reckoning estimates I improved the method using behavioural definition to identify real moves (steps, grazing, moving) and distinguish it from resting, grooming and other behaviours not leading to a displacement of the animal in space, allowing to selectively filter data to be dead-reckon. Using the data collected, I showed that central-place-based, but free-roaming, domestic goats exhibited efficient space-use by having time-dependent fanning out from their central place, which reduced local resource depletion. Models predicted that area-use increased logarithmically with herd size and duration. These finding could lead to improved livestock management in multi-functional alpine landscapes, to reduce the risk of over-grazing and manage interactions with other grazing species and clonflicts with other landuse needs. The goat grazing patterns were compared to those of wild ibex and revealed goats to be more adaptable, with the ibex being particularly vulnerable to changes in temperature, exacerbated by them preferring steep slopes with associated high metabolic costs and heat generation during ascent. These results could further inform management decisions regarding the survival of alpine ibex under projected climate change. Furthermore I developed new biologging approaches to investigate social interactions, specifically head-clashing in both species. This agonistic behaviour was associated with competition and the rut in ibex and was quantified using methods first developed for the domestic goat, where the behaviour appeared to relate primarily to competition for food. Using the goat as a surrogate species, the behaviour could be identified and mapped for the ibex, which highlighted areas and times important for head-clashing, including drastic increases during the rut. Finally, movement data and proxies for energy expenditure from three domestic species (sheep, cows and goats) and three wild species (ibex, mouflon and chamois) was utilised to produce species-specific energy landscapes across the terrains they used. This indicated that different anatomies and behaviours resulted in different, species-specific, movement costs for specific topographies and habitats. Energy use for travel across heterogeneous space depends, therefore, on the species concerned. These findings thus highlight the importance to consider that species with different life histories and ecological needs use landscapes in contrasting ways and my results can provide a more refined evidence base for the management and conservation of these species in alpine grasslands. These biologging approaches allow now also to address further management issues such as the responses to disturbances from tourists (hiking, skiers, etc.) and even reveal how species are more susceptible to climate change.

Environmental and individual-level drivers of movements and space use in three ungulate species

“…Dead-reckoning between GPS fixes was achieved using accelerometers (20 Hz recording frequency) and magnetometer (8 Hz recording frequency) to derive animal Vectorial Dynamic Body Acceleration (VeDBA) and heading with respect to magnetic North (subsequently corrected to true North). From Redcliffe (2021). (B) The same path subsampled at 1 location/20 min to which we apply a Hidden Markov Model with 3 latent states supposed to be proxies of Resting, Foraging and Relocating Behaviour.…”

“…As head clashes frequency also increased with distance moved (c) and time spent grazing by goats (d), the author argues that head clashes in the edges of goat ranges may indeed likely be related to interference competition for higher resources. From Redcliffe (2021)…”

“…. Further research investigating how females' spatial behaviours are related to their age, as well as the presence of conspecifics of varying ages, is thus required to disentangle the influence of experience, and dominance (Figure 5, the "landscape of rage", Redcliffe, 2021)., on chamois spatial ecology and energy acquisition, especially in a context of global warming where the earlier green-up and senescence of vegetation may accentuate the effects of competition. This is all the more important given that the age-related differences in energy acquisition, either related to experience or dominance, may lead to age-structured heterogeneity in survival and reproductive success , with potentially cascading consequences on population dynamics .…”