Humans exert a growing influence over climate characterized by rising temperatures and associated regional changes in weather patterns affecting the quantity and timing of precipitation. This is particularly preoccupying in arid and semi-arid ecosystems, such as southern African savannas, which have experienced a significant decline in rainfall, an increase in the severity of droughts and an extension of the dry season, and for which models generally predict that rainfall will continue decreasing. This increasing aridity is expected to alter the functioning of natural ecosystems. In this context, a key issue is how species interactions will evolve with changes in environmental conditions. The aim of the project FUTURE-PRED is to provide one of the first empirical study to measure the impacts of changes in environmental conditions on predator-prey interactions in a large mammalian system. Whereas cursorial predators chase down their prey over long distances and are therefore more likely to kill weak individuals, ambush predators rely on concealment to hunt by surprise prey moving within a chasing distance, and hence their hunting success is mainly dependent on concealment opportunities. Arid and semi-arid ecosystems are characterized by two contrasting (wet and dry) seasons. As the dry season progresses, there are fewer leaves on woody plants, grass becomes sparser and shorter, and vegetation quality decreases, leading to two major changes likely to affect predator-prey interactions: (i) large herbivores become in poorer body condition and hence are expected to become easier to catch by cursorial predators, and (ii) vegetation provides less concealment opportunities for ambush predators, which should then become less efficient hunters. We will first evaluate how environmental conditions (through comparison of dry and wet seasons, changes as the dry season progresses, and comparison of 2 areas) affect the hunting success of the two most common African apex carnivores characterized by contrasting hunting modes (the African lion - ambush predator - and the spotted hyaena - cursorial predator -). We will equip 15 individuals of each species for 3 years with GPS-collars with satellite transmission of the GPS data and integrated tri-axial accelerometers-magnetometers to test the hypotheses that as the dry season progresses, the hunting success of cursorial predators increases while that of ambush predators decreases. Thanks to the field investigation of feeding sites, we will further assess the type of prey eaten (prey species, age class, livestock vs. wild prey, body condition), the characteristics of the surrounding vegetation, and whether the contribution of scavenging to foraging tactics changes. Finally, we will investigate the consequences of increasing dryness and associated changes in carnivore hunting success on carnivore population dynamics by (i) assessing whether higher carnivore hunting success leads to higher carnivore reproduction success, (ii) studying the role of environmental conditions on carnivore survival and population dynamics through the analysis of a long-term individually based lion dataset (840 individuals in 45 groups since 1999), and (iii) modelling carnivore population dynamics under different scenarios of climate change based on our findings. To our knowledge, such a mechanistic approach to bridge the gap between individual behaviour and population dynamics has never been done for a large carnivore species. FUTURE-PRED will be led and coordinated by Marion Valeix, and carried out in the CNRS LTSER (Zone Atelier) Hwange, Zimbabwe. By combining original new data with long-term individually based monitoring of large mammalian carnivores, the project FUTURE-PRED has the ambition to provide an integrative study of the effect of environmental conditions on large mammalian predator-prey interactions.