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Background: In the seasonal tropics, fire generally occurs in the dry season. Consequently, the effects of fire and dry season drought on seedling establishment of different tree functional types are correlated. Therefore, factors that are more important for tree recruitment in forest-savanna ecotones are still poorly understood. Methods: We studied seedling establishment success of seven tropical tree species (of forest and forest-savanna transition origins) in a common garden experiment using combinations of dry season (irrigation vs no-irrigation) and fire (burning vs no-burning). Results: We found that burning caused a significant decline in survival of forest species, but not of forest-savanna transition species. The combination of burning without dry season irrigation (which typifies dry season fire) had the largest overall effect on survival, mass and height of plants. The separate effect of burning was larger than that of dry season drought. Seedling size at the onset of the dry season significantly predicted root starch content and, hence, dry season survival probability of forest-savanna transition species, but not of forest species. Dry season irrigation increased post-fire survival of forest-savanna transition species, but not of forest species, possibly linked to differences in resprout capacity and root starch reserves. Conclusion: Our work shows that fire and dry season drought produce a stronger negative effect together, than their separate effects on seedling establishment particularly of forest species. This provides a mechanistic explanation for the existence of forest-savanna transition species in fire-prone humid savannas. Implications for Conservation: The mosaic of forest, transitional and savanna vegetation within the forest-savanna ecotone reflects the influences of fire and dry season drought. Any changes in these elements will influence vegetation dynamics within the forest-savanna ecotone. [ABSTRACT FROM AUTHOR]

Animal activity patterns vary on a daily, circalunar and seasonal scale in response to abiotic (e.g. light availability and temperature) and biotic factors (e.g. predation and competition). In the presence of humans and their livestock, carnivores, for example, have been found to become more nocturnal. The aim of this paper is to compare daily, circalunar and seasonal activity patterns of cheetah Acinonyx jubatus in the western Kalahari of Botswana between areas where there is no livestock present (i.e. game farms with a relatively low risk of cheetah mortality) and areas where livestock is present (i.e. cattle farms with a higher risk of cheetah mortality). Using two years of camera trap data, we recorded 88% of cheetah observations on game farms and 12% on cattle farms. Our results showed that cheetahs were more nocturnal in the absence of cattle and more crepuscular on cattle farms compared to game farms. Overall, cheetah activity on cattle farms showed a peak in activity after inferred cattle activity and before human activity during the day, specifically during the dry season. We recommend management strategies on a local scale such as temporal zoning of grazing activities during the different seasons or keeping cattle in an enclosure at night. This study sheds new light on our understanding of the impact of land use on free-ranging carnivores in the face of livestock expansion on the African continent. [ABSTRACT FROM AUTHOR]

Ungulates serve as the primary carrion source for facultative scavengers in European ecosystems. In the absence of large carnivores, such as wolves (Canis lupus), human hunting leftovers are the main source of carrion for these scavengers. Additionally, wild boars (Sus scrofa) are heavily culled in many ecosystems and are both a significant prey species for wolves as well as a key scavenger. Nowadays, wolves and wild boars are re‐establishing their historical home ranges. However, it remains unclear how their presence influences the population dynamics of facultative scavengers under different scenarios of human hunting strategies. We simulated the biomass densities of all states in the trophic web including European scavengers and wolves using an ordinary differential equations (ODE) model. The presence of wolves led to a positive trend in scavenger biomass in general. However, in general, we found that plant‐based resources were more important for scavenger dynamics than carrion, regardless of whether the carrion originated from human hunting or wolf predation. Only when wolves were absent but boars present, the human hunting strategy became important in determining scavenger dynamics via carrion supply. In conclusion, our model indicates that population dynamics of facultative scavengers are not mainly driven by the availability of carrion, but rather by the presence of and competition for vegetation. Furthermore, our simulations highlight the importance of adapting human hunting strategies in accordance with the re‐establishment of wolf and boar as these can cause fluctuating population patterns over the years. [ABSTRACT FROM AUTHOR]

The Rhine sculpin (Cottus rhenanus) is a benthic rheophilic fish species that is endemic to tributaries of the rivers Rhine and Meuse in North-western Europe. Little is known about its occurrence and individuals density in relation to habitat characteristics. A core population of C. rhenanus occurs in the River Geul in the Netherlands. Since the late 19th century, this river was heavily polluted by communal and industrial wastewater, causing a strong population decline. As the core population of C. rhenanus is recovering, the status, distribution, and habitat use could be studied to facilitate recovery in other locations. Cottus rhenanus density of individuals significantly increased over the period 2005–2015 and it became one of the most abundant fish species in assemblages. Negative relationships were observed between C. rhenanus densities and a high abundance of boulders (>200 mm), large structures such as woody debris, and water depth. The population increase and recolonization of C. rhenanus coincided with water quality improvement, which suggests that this fish species can be used to assess small streams ecosystem integrity. The recent range expansion of the Ponto-Caspian round goby (Neogobius melanostomus) poses a high risk of negative effects on C. rhenanus populations via food and shelter competition. Further water quality improvement, habitat conservation, and prevention of the spread of invasive gobies could favour C. rhenanus populations within their natural range.

Raptors exert top‐down influences on ecosystems via their effects on prey population dynamics and community composition. Most raptors are sympatric with other predators, thus complicating our understanding of their relative influence in these systems. Estimates of kill rates and prey biomass recycling have been used as predation metrics that allow quantitative comparison among species and assessment of the relative role of single species within complex food webs. Few studies have produced findings of kill rates or prey biomass recycling for raptors. We used a supervised machine learning algorithm to behaviourally classify high resolution accelerometer informed GPS locations of tagged adult non‐breeding martial eagles Polemaetus bellicosus in the Maasai Mara region of Kenya to estimate kill rates and prey biomass recycling. Eagle locations classified as feeding were clustered using distance and time thresholds to identify kills and calculate kill rates. Identified kill sites were quickly ground‐truthed to confirm kills and identify prey species. We estimated kill rates for martial eagles at 0.59 kills day‐1 for males and 0.38 kills day‐1 for females, and we estimated biomass recycling per ground‐truthed kill at 1796 g for males and 3860 g for females. From our sample of identified ground‐truthed kills, 'gamebirds' was the most frequently recorded prey category for male eagles and 'small ungulates' was the most frequently recorded prey category for female eagles. These results position martial eagles close to sympatric mammalian top predators in trophic pyramids and provide evidence for their classification as a top predator. [ABSTRACT FROM AUTHOR]