Interspecific interactions shape the structure of animal communities, and they rely on a number of multifactorial mechanisms, including e.g. activity rhythms, ectoparasite prevalence, predation ...pressure and food habits. Despite this, no study has analysed multispecies interactions by combining such a high number of aspects, mostly because the experimental manipulation of studied populations is rarely possible. In our work, we assessed several aspects of interspecific interactions in a rodent assembly composed by three species, by examining diet and temporal- niche partitioning, as well as relevant ectoparasite load and predation pressure, in a natural environment. We analysed stomach contents and ectoparasite load of 78 individuals belonging to all the species, whereas activity rhythms were measured with camera trapping (2200 night-traps, throughout 1 year). Our findings showed that the largest-sized species, i.e. the brown rat
Rattus norvegicus
was the strongest competitor and may affect diet, temporal behaviour and susceptibility to parasites of smaller-sized ones, i.e. the black rat
Rattus rattus
and the house mouse
Mus domesticus
. Larger-sized species showed a broader trophic niche with respect to smaller-sized ones, whereas the smallest species seemed to avoid the largest ones by shifting its temporal activity when the latter was mostly inactive. Larger-sized species may also act as potential predators towards smaller ones, which are also more vulnerable to ectoparasite infestation and to the predation by the only raptor bird present in the study area, the barn owl
Tyto alba
. We therefore highlight the importance to carry out community-wide studies, to understand interspecific intraguild relationships.
The Mediterranean Sea is a hotspot for shark conservation. A decline in large pelagic shark populations has been observed in this vast region over the last 50 years and a lack of data on the local ...population status of various species has been pointed out. Throughout history, the relation between people and sharks has been revolving around a mixture of mystery, fear, and attraction. Recently, however, a remunerative ecotourism industry has been growing in areas of shark aggregation globally. This growth has been accompanied by the establishment of a citizen science (CS) movement aimed to engage and recruit ecotourists in data collection for shark research. Several CS projects have generated interesting results in terms of scientific findings and public engagement. In the Mediterranean Sea, shark aggregations are not as relevant to support locally-focused CS actions on shark diving sites as in other parts of the world. However, a series of other initiatives are taking place and CS could offer an excellent opportunity for shark conservation in the Mediterranean Sea. The dramatic decline of shark populations shown in the region calls for alternative ways to collect data on species distributions and abundance. Obtaining such data to set proper conservation and management plans for sharks in the Mediterranean Sea will be possible if existing CS initiatives collaborate and coordinate, and CS is widely acknowledged and deployed as a valuable tool for public education, engagement, and scientific discovery. After providing an overview of multiple facets of the relationship between humans and sharks, we focus on the possibility of exploiting new technologies and attitudes toward sharks among some groups of ocean users to boost participatory research. CS is a great opportunity for shark science, especially for areas such as the Mediterranean Sea and for large pelagic sharks whose populations are highly impacted.
Species diversity assessments are an important step to evaluate the conservation status of a community, both in marine and terrestrial ecosystems. These assessments are pivotal if related to both, ...the constant increase of human pressure on ecosystems and the anthropogenic climate change occurring nowadays. Sharks and rays are globally threatened, and the situation is particularly alarming in the Mediterranean Sea where more than 50% of species are listed at risk of extinction by the International Union for Conservation of Nature (IUCN). In this paper, we revise and discuss the chondrichthyan species richness of the Mediterranean and the Black Sea. Through an accurate review of published taxonomic studies, historical data on species occurrence, analyses of scientific survey data and biodiversity databases and other scientific papers, we produced a revised list of species whose presence in the Mediterranean Sea is confirmed or highly probable and discussed on current taxonomic and occurrence disputes on the species that are instead rarer or claimed to be locally extinct. We listed a total of 88 species, representing 30 families and 48 genera that are currently present in the Mediterranean and the Black Sea. This number includes 48 shark species, 38 batoids, and 2 chimaeras. The review represents a reference for future conservation assessments of cartilaginous fish in the region and a guide for decision-makers when promoting the sustainable exploitation of fisheries resource within an ecosystem-based framework. This paper can help to set a baseline of the Mediterranean species and thus resolve some uncertainties regarding their conservation status, explaining the reasons for their prolonged absence in the reports. Indeed, failure to record over time may not be due to grubbing up, but because after careful review this species was not really part of the Mediterranean fauna.
Assessing the spatiotemporal overlap amongst animal species living in sympatry helps to shed light on mechanisms of interspecific coexistence. We analysed the spatiotemporal coexistence in a ...predator–prey system through multiyear camera trapping, in a mountainous protected area of southern Italy (January 2012–January 2017). Temporal activity patterns and their interspecific overlap, as well as spatial overlap, were estimated for a top predator, that is the wolf Canis lupus, three species of wild ungulates, four mesocarnivores, one small herbivore, livestock and humans. A wide nocturnal temporal overlap was detected between the wolf and almost all the other species (71–91%). The highest temporal (91%) and spatial (63%) overlaps were reported between the wolf and the red fox Vulpes vulpes. For wolf‐ungulate pairs, the highest temporal overlap (88%) was reported for the wild boar Sus scrofa, its local main prey. Considering all the other species pairs, spatial overlap was low (i.e. lower than 45%), whereas temporal overlap was substantial (71–91%). Our findings support a significant role of interspecific spatial partitioning in shaping coexistence amongst considered species, which might be influenced by differences in spatial distribution of different food resources.
Spatiotemporal activity patterns and their interspecific overlap were estimated for the grey wolf, three species of wild ungulates, four mesocarnivores, one small herbivore, livestock and humans. A wide nocturnal overlap was detected between the wolf and most other species, and their spatial overlap was the highest with the red fox. We found a significant role of interspecific spatial partitioning in shaping coexistence among considered species, which might be influenced by differences in the spatial distribution of different food resources.
Relationships among carnivore species are complex, potentially switching from competition to facilitation on a context-dependent basis. Negative associations are predicted to increase with latitude, ...due to limited resources emphasising competition and/or intra-guild predation. Accordingly, a stronger negative correlation between large- and meso-carnivore abundances should be expected at higher latitudes, with a substantial spatio-temporal partitioning favouring interspecific coexistence. Human presence may influence spatio-temporal relationships between (meso)carnivore species, as it can be perceived as a risk factor, but anthropogenic food can also provide an important additional food resource. Using camera-trap data, we studied the spatio-temporal associations between two of the most widespread carnivores in Europe, i.e., the red fox and wolf. We compared their monthly/daily spatio-temporal partitioning between two different landscapes: Białowieża Primeval Forest (Poland) and the Mediterranean Maremma Regional Park (Italy). We predicted a stronger interspecific partitioning, as well as more attraction of red foxes to humans in the northern site (Poland). Temporal activity patterns of the two carnivores overlapped in both sites, and their detection rates were positively associated, even though in weaker way in Poland. We observed a positive spatial association of red foxes with human activity in Białowieża, but not in Maremma. This association occurred only at a monthly temporal scale and disappeared at a daily scale, suggesting some disturbance in the shorter term. Our results provided partial support to our predictions and suggest that, despite the ecological differences between our study areas, only weak differences in wolf-fox relations were observed, suggesting that red fox responses to wolves may be relatively comparable over large spatial scales.
To characterize HIV-infected patients with neurosymptomatic cerebrospinal fluid (CSF) 'escape', defined as detectable CSF HIV RNA in the setting of treatment-suppressed plasma levels or CSF RNA more ...than 1-log higher than plasma RNA.
Retrospective case series.
Four urban medical centers in the United States and Europe.
Virologically controlled HIV-infected patients on antiretroviral therapy (ART) with progressive neurologic abnormalities who were determined to have CSF 'escape'. INTERVENTION Optimization of ART based upon drug susceptibility and presumed central nervous system exposure.
Levels of CSF HIV RNA and inflammatory markers, clinical signs and symptoms, and MRI findings.
Ten patients presented with new neurologic abnormalities, which included sensory, motor, and cognitive manifestations. Median CSF HIV RNA was 3900 copies/ml (range 134-9056), whereas median plasma HIV RNA was 62 copies/ml (range <50 to 380). Median CD4 T-cell count was 482 cells/μl (range 290-660). All patients had been controlled to less than 500 copies/ml for median 27.5 months (range 2-96) and five of 10 had been suppressed to less than 50 copies/ml for median 19.5 months (range 2-96). Patients had documentation of a stable ART regimen for median 21 months (range 9-60). All had CSF pleocytosis or elevated CSF protein; seven of eight had abnormalities on MRI; and six of seven harbored CSF resistance mutations. Following optimization of ART, eight of nine patients improved clinically.
The development of neurologic symptoms in patients on ART with low or undetectable plasma HIV levels may be an indication of CSF 'escape'. This study adds to a growing body of literature regarding this rare condition in well controlled HIV infection.
Nest predation is reported as a cause of reproductive failure of ground‐nesting bird species whose populations in Europe are declining. Conversely, European populations of the wild boar Sus scrofa ...have been expanding, leading to increasing threats to habitats and ecological communities. The impacts of wild boar on ground‐nesting bird species are poorly known and have never been explicitly assessed. We conducted an artificial ground‐nest experiment in Mediterranean habitats of central Italy using camera traps to assess predator identities. Deployed nests contained quail or chicken eggs, and predation occurred within one week for 47/48 deployments carried out during March‐July 2020. The wild boar was the most common predator (36% deployments), followed by the magpie Pica pica (18%), the red fox Vulpes vulpes (10%) and the pine marten Martes martes (10%). Predation by other species was occasionally observed. Egg type and deployment habitat did not significantly influence time to predation or the likelihood that a nest was preyed upon by wild boar, respectively. The presence of a stuffed gull close to the nests significantly delayed predation. Nests preyed by birds and mammals other than wild boar were often subsequently scavenged by wild boar, which consumed the remaining eggs or eggshells. Time to predation increased from spring to summer, suggesting a reduction of predation intensity during periods when the availability of natural eggs is lowest. The likelihood of a nest being preyed upon by the wild boar compared to other predators increased when wild boar frequency of occurrence in 1‐week camera trap shootings was the highest, suggesting that higher abundance/activity of this species triggered increased egg predation. The wild boar might act as major predators of ground‐nesting bird species in Mediterranean habitats and the large‐scale population increase of this ungulate should be considered a significant threat to ground‐nesting species of European conservation concern.
We found that the wild boar was the most common predator of ground nests in Central Italy, followed by the magpie, the red fox and the pine marten. Nests preyed by birds and mammals other than wild boar were often subsequently scavenged by wild boar which consumed the remaining eggs or eggshells. The wild boar might act as a major predator of ground‐nesting bird species in Mediterranean habitats and the large‐scale population increase of this ungulate should be considered a significant threat to ground‐nesting birds of European conservation concern.
We report a 2000-year Antarctic ice-core record of stable carbon isotope measurements in atmospheric methane (delta¹³CH₄). Large delta¹³CH₄ variations indicate that the methane budget varied ...unexpectedly during the late preindustrial Holocene (circa 0 to 1700 A.D.). During the first thousand years (0 to 1000 A.D.), delta¹³CH₄ was at least 2 per mil enriched compared to expected values, and during the following 700 years, an about 2 per mil depletion occurred. Our modeled methane source partitioning implies that biomass burning emissions were high from 0 to 1000 A.D. but reduced by almost approximately40% over the next 700 years. We suggest that both human activities and natural climate change influenced preindustrial biomass burning emissions and that these emissions have been previously understated in late preindustrial Holocene methane budget research.
Abstract
Female density and distribution are dependent on resource phenology and female availability strongly influences male mating behaviour and success. When a male adopts a ‘resource defence’ ...tactic, his reproductive success depends on the location and attractiveness of his territory. Environmental factors associated with territory quality are expected to influence mating success, for example, through territory features or male–male competition. In a protected population of a mountain‐dwelling polygynous herbivore, the Alpine chamois
Rupicapra r. rupicapra
, we investigated the relationships among mating opportunities, some environmental variables (snow depth, topographic features and size of territories) and male intra‐sexual competition for mating. We recorded the mating behaviour and territory size of 15 GPS‐GSM radio‐tagged territorial males, during five rutting seasons (early November to early December:
N
= 8 individuals in 2011,
N
= 9 in 2012,
N
= 8 in 2015,
N
= 11 in 2016,
N
= 7 in 2017; 80% of them were observed for more than one mating season) and related them to snow depth and topography of territories. In ruts with deep snow cover, territorial males had smaller territories and higher number of mating opportunities than in ruts with lower snow cover. Smaller territories showed the highest values of terrain roughness, in turn with little or no snow cover in the mating season, and were visited by a greater number of females, than larger territories. Number of wins was positively influenced by snow depth and negatively related to the frequency of aggressions. The frequency of male–male aggressive interactions was greater during ruts with deep snow cover and for males with territories at higher elevations; additionally, it was negatively related to interactions won. Thus, snow depth, which influences resource distribution and female movements, is confirmed as a strong determinant of male mating opportunities and mating behaviour.
Ecological theory predicts that sympatric species should avoid competition through diet, spatial and/or temporal partitioning. In carnivores, interference is widespread between species with similar ...diets. Smaller species are expected to differentiate their diet from that of larger, dominant ones, to reduce the risk of potentially lethal encounters. Interference has been reported between tigers and common leopards, with the former dominant over the latter. In 2009–2011, in an area of Terai, South‐West Nepal, we assessed food habits and prey selection of tigers and common leopards, to evaluate whether prey partitioning occurred between these large cats. Prey availability was high, both in terms of number of species (at least seven wild ungulates beside livestock, two primates and an array of smaller prey) and density (large ungulates, livestock and primates: 130.8–174.8 individuals per km2). Wild vertebrates were the staple of both cats (tigers: 82.7%; common leopards: 66.6%), but common leopards used livestock significantly more than tigers did. Diet breadth of leopards was c. 20% larger than that of tigers, indicating a broader trophic niche. Significant differences in prey use and selection occurred between tigers and leopards, with the former using large (i.e. >100 kg) prey more often and small (i.e. 5–25 kg) prey less often than the latter did. Medium‐sized prey were taken in comparable proportions by the two cats, with a great overlap of diet (Pianka index: 0.85). In conclusion, in our study area, apparently tigers and leopards did not base their coexistence on diet partitioning, suggesting a major role for spatial and/or temporal partitioning.
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