Human-induced high densities of large wild herbivores may pose a threat to natural ecosystems, modifying biodiversity and ecosystem functioning. Although the negative impacts on individual taxa and processes are well documented, a comprehensive understanding of how ecosystem integrity responds to high herbivore densities remains limited. This study addresses this gap through an extensive herbivore-density manipulation experiment conducted in two Mediterranean woodlands. We established two scenarios of high red deer (Cervus elaphus) density, representative of some protected areas (~30 individuals·km2) and intensively managed hunting estates (~90 individuals·km2). We monitored 38 metrics encompassing a broad spectrum of biodiversity and functional responses to synthesize the short-term impacts of high herbivore densities. We revealed an overall 13% decline in ecosystem integrity after one year of exposure to high herbivore densities, with particularly widespread impacts on functional responses and detrimental effects on biodiversity components. We detected rapid declines in plant diversity and a positive response of epigeic invertebrate orders. Conversely, ants (analyzed separately), birds, and small mammals remained mostly unaffected. Functional responses were consistently impaired, including declines in plant regeneration and physiological performance, simplified pollination networks, degraded soil structure, and increased disease vectors. These findings show that human-induced high herbivore densities rapidly create conditions that disrupt ecosystem integrity, reveal early signs of ecological degradation, and underscore the urgent need for population regulation.

Large herbivores foster direct and indirect cascading effects on ecosystems, being considered key elements for ecological functioning and restoration. Empirical knowledge supporting restoration programs involving large herbivores is still very limited in Mediterranean ecosystems. For instance, few studies have explored how small mammals’ body condition vary across different levels of herbivore pressure. Small mammals are keystone species in the dynamics of Mediterranean habitats due to their role as seed dispersers and prey. In this study, we performed a seasonal and fine-scale experiment in a fenced Mediterranean area in north-eastern Portugal, to assess the population and individual response of small mammals (one rodent, wood mouse Apodemus sylvaticus and one insectivorous, greater white-toothed shrew Crocidura russula) to the effects of herbivores pressure, seasonality, landscape structure, and sex-related differences. Our results showed that the wood mouse was more abundant in the spring, while the shrew was particularly abundant in open areas with higher herbivory pressure, which may be related to a greater abundance of dung-associated arthropods. Body condition of both species improved in spring, while the presence of rocky outcrops also promoted a positive effect on wood mouse body condition. These structures can contribute to thermoregulation and offer refuge from disturbances caused by large herbivores. This study suggests that the coexistence of small mammals and large herbivores is mediated by several factors governed by the complexity of Mediterranean habitats.

Sarcoptic mange, a widespread and highly contagious disease caused by Sarcoptes scabiei mites, affects a wide range of mammals, including the red fox (Vulpes vulpes). Being a zoonosis, mange can be considered a potential public health issue, of conservation relevance, as many wildlife species are susceptible to mite infection, with impacts on individuals’ fitness and populations’ viability. This study aimed to estimate the prevalence and investigate the factors associated with the occurrence of sarcoptic mange compatible lesions in red fox populations in Portugal. Using camera trap datasets and a Generalized Linear Mixed Effects Models (GLMM) approach, we inspected images of foxes for probable signs of mange and tested hypotheses related to ecological and environmental drivers of disease occurrence: climate conditions, land use composition and structure, host community abundance, soil composition, and altitude. Our results showed that 2.9

Ongoing global environmental changes demand cost-effective strategies to restore ecosystem functioning. Within this context, the reintroduction of large mammalian herbivores has emerged as a promising approach to recover ecological processes and foster self-sustaining, biodiverse ecosystems. However, the impacts of such initiatives remain poorly understood, particularly regarding their effects on soil functions and ecological processes. We tested whether large herbivore densities (wild horses (Garrano breed) and cattle (Maronesa breed, an ancient lineage close to aurochs) modulates soil multifunctionality (the simultaneous provision of multiple ecosystem functions) across habitats (grasslands, shrublands, and forests) and seasons (fall and spring) in a Mediterranean landscape. Using composite multivariate indices describing soil functions related to biogeochemical cycles (i.e., enzymatic activities) and physicochemical properties (pH, conductivity, organic matter, and nutrient loads), we found that soil enzymatic activities varied seasonally, being higher in spring, and interacted with habitat and herbivore pressure gradients. Habitat and herbivore pressure explained the variation in soil multifunctionality during spring, while in fall it was mainly driven by herbivore pressure. Enzymatic stoichiometry, particularly C:P ratios, strongly predicted soil fertility and multifunctionality, showing positive relationships in forest habitats and under herbivore pressure. A mechanistic approach confirmed that herbivore impacts on soil functioning operated primarily through changes in soil properties and nutrient cycling rather than direct effects. Mediterranean landscapes are rapidly changing, and our results highlight herbivore management as a key tool to sustain soil ecological processes under the rewilding framework. ### Competing Interest Statement The authors have declared no competing interest. Fundação para a Ciência e Tecnologia, CEECIND/01428/2018,, 2021.00690.CEECIND/CP1659/CT0029), 2021.05387.BD, PD/BD/150645/2020, 2023.00109.RESTART, UID/50017/2025 and LA/P/0094/2020 National Science Foundation, DEB# 2120677)

Large herbivores drive ecosystem functions and processes through their direct or indirect impact on different habitats and wildlife communities. Some studies have assessed the impact of large herbivores on the small mammal diversity and abundance, but fewer have assessed how rewilding with large herbivores impact seed dispersal by rodents. Here, we assessed the impact of “Maronesa” cows, a cattle breed closely related to the extinct aurochs (Bos primigenius), on acorn removal and dispersal dynamics in a typical Mediterranean habitat. This study was conducted in the Faia Brava Reserve located in the Greater Côa Valley (North-Eastern Portugal) as part of the Rewilding Europe program, where it was possible to distinguish three areas: 1) current “Maronesa” herbivory (since 2012), 2) historical herbivory (2012–2022), and 3) control area (i.e., without any records of large herbivores). Our results showed that acorn removal rates were significantly higher in areas with large ungulate herbivory (historical and current) than in the control area. Acorn removal in historical herbivory was caused only by scatter-hoarding rodents, whereas in current herbivory it was mainly caused by large herbivores that act as acorn predators. Interestingly, dispersal distances were greater in the historical herbivory compared to the current herbivory. Microsites of seed deposition also varied with large herbivore rewilding, as rodents dispersed the seeds to open microsites when large herbivores were present, whereas without herbivory, seeds were mostly deposited and predated under plant cover. These findings highlight the potential consequences of large herbivore rewilding on the regeneration of oak-dominated Mediterranean ecosystems through cascading effects on the seed dispersal process.

Identifying the drivers and ecological mechanisms that shape species occupancy patterns at large scales is decisive in understanding how species respond to environmental changes. In this study, we compiled camera trapping data from different scientific projects and monitoring programs to conduct the first assessment of the relevant ecological drivers of red fox (Vulpes vulpes) occupancy patterns at the national level in Portugal. Here, using single-species/single-season occupancy models, we targeted Portugal divided into two regions with different environmental contexts - north and south of the Tagus River. Our results show that the red fox occupancy drivers change depending on the environmental context. In the northern region (more mountainous and densely forested), occupancy patterns were shaped mostly by direct human-associated disturbance, positively associated with dogs’ relative abundance index. On the other hand, in the southern region (mainly plain areas dominated by agroforestry systems), the variation in red fox occupancy patterns was best explained by the habitat characteristics, with foxes showing a higher probability of occupying areas with greater habitat diversity. Considering these results, we conclude that the red fox’s generalist character is highlighted by its capacity to adopt different occupancy strategies depending on the environmental context: the use of more humanized areas, along with free-ranging dogs, in the Northern region, and the use of areas with more diversified resources in the Southern region. Therefore, our study reinforces the red fox’s highly adaptive character, adding crucial information to tailor red fox management and conservation actions to Portugal’s different regional environmental contexts.

Wild ungulate-vehicle collisions (UVC) in Europe have dramatically increased, creating serious conservation, economic and health problems. To examine which temporal and environmental features promote UVC involving the three most abundant and widely distributed wild ungulate species in Portugal (wild boar, red deer and roe deer), we used Generalized Linear Models, using a database of 3,374 UVC (2019–2022). We evaluated the influence of hour, day, month, hunting season, breeding season, lunar phase, meteorological conditions and land cover on the patterns of the wild ungulate-vehicle collisions. Temporally and spatially, UVC were not randomly distributed and the distribution was species-specific. Different factors explained the vehicle collisions for different species, being precipitation, time after dusk, forest and urban area around the collisions the drivers common for all the species. Hunting season also explained the wild boar collisions and both hunting and breeding season explained both wild boar and roe deer vehicle-collisions. Our results may be considered an important step towards the development of nationwide and space-time collision risk maps to be incorporated on navigation and mapping services. The information provided in this study emphasis the need for the optimization of ongoing mitigation measures and the need to focus them on periods of elevated collision risk, namely during twilight periods.

ABSTRACT The Iberian Peninsula is witnessing ever‐faster environmental changes, and new challenges for wild ungulates are continuously emerging as they become more abundant and widespread. We conducted a systematic review to analyse the knowledge on wild ungulates inhabiting the Iberian Peninsula. We used Web of Science and Scopus search engines, complemented by searches in nonindexed journals, to examine peer‐reviewed articles published between January 1990 and July 2023. The annual average growth rate in the number of publications was 17%. Most studies focussed on diseases and pathogens (36%), physiology, endocrinology and reproduction (19%), and behaviour, population and community ecology (17%). Red deer and wild boar are the most targeted species in scientific literature, followed by the Iberian wild goat, roe deer, fallow deer, Southern chamois, mouflon and aoudad. We identify key knowledge gaps that deserve further attention such as the ecological and social impacts of (re)introductions, the effects of increasing ungulate densities on ecosystem integrity and the impact of different hunting and management techniques (some unique to the Iberian Peninsula) on population dynamics. We also highlight the need to stimulate Iberian collaboration and extend the discussion to a wider range of stakeholders to integrate different perspectives on the research agenda for Iberian wild ungulates.

Fiber is essential for rumen health, microbial fermentation, and the energy supply of herbivores. Even though the study of fecal fiber contents (neutral detergent fiber NDF, acid detergent fiber ADF, and acid detergent lignin ADL) using near-infrared reflectance spectroscopy (NIRS) has allowed investigating nutritional ecology of different herbivore species, NIRS calibrations are species-specific and require a large number of samples for predictions. A multispecies calibration would be an advantage since samples from different herbivores could be used to calibrate a model capable of predicting the fecal fiber content of other herbivores. To date, however, multispecies models have not been developed to predict fiber contents in the feces of herbivores. Here, we fill this gap by calibrating three fiber multispecies models (NDF, ADF and ADL) using fecal samples from domestic and wild herbivore species. We also evaluated the effect of incorporating sodium sulfite in fiber determination protocol. The initial dataset consisting of 445 samples of six herbivore species was used to calibrate (80% of the samples) and validate (20% of the samples) the models. Subsequently, 63 samples of five herbivores not included in the calibration set were used for the external validation of the model. Since sodium sulfite did not significantly improve fecal fiber prediction, our model was developed without this compound. The multispecies models obtained were highly accurate determining NDF, ADF and ADL (R2CAL, coefficient of determination in calibration, ≥ 0.93, R2VAL, coefficient of determination in validation, ≥ 0.91) and independent of external confounders. For external validation, the accuracy in predicting fecal samples in other herbivore species was also satisfactory, with consistently better values for NDF (R2VAL, 0.86-0.94) and ADF (R2VAL, 0.80-0.95) than for ADL (R2VAL, 0.66-0.89). We show that multispecies NIRS calibrations can be used with high accuracy to assess fecal fiber contents across diverse herbivore species. This finding represents a significant advance in the study of the nutritional ecology of herbivores with contrasting foraging patterns. In the future, widening the data range (e.g., species and locations) of the initial dataset could further improve the accuracy of these models.

Blastocystis is a ubiquitous intestinal protist in humans and animals worldwide. The traditional livestock free-roaming raising system in rural communities increases the risk of infection with contact with a wider range of pathogens transmitted via the faecal-oral route associated with that wildlife-livestock-human interface. However, no studies have been conducted to determine the occurrence and subtype distribution of Blastocystis in livestock in Portugal. Here, we collected 180 faecal samples from herbivore livestock (cattle, goats, horses, and sheep) in different regions of the country to investigate Blastocystis prevalence and subtype diversity using PCR and next-generation amplicon sequencing. Blastocystis was present in 40.6% (73/180; 95% CI: 33.31-48.11) of the samples (goats, 81.0%; sheep, 60.9%; cattle, 32.2%). None of the horse samples were Blastocystis-positive. Eighteen subtypes were detected (ST1-ST3, ST5-ST7, ST10, ST13, ST14, ST21, ST23-ST26, ST30, ST42-ST44). Mixed infections were detected in 97.3% of the Blastocystis-positive samples. Potentially zoonotic subtypes were identified in 75.0%, 96.4%, and 100% of the Blastocystis-positive specimens collected from cattle, sheep, and goats, respectively. These results demonstrate that cattle, sheep, and goats harbour a high diversity of Blastocystis subtypes in the study regions. Importantly, our data provide novel molecular evidence strongly suggesting that some Blastocystis STs/ST subgroups may have differential host specificity.

Trophic rewilding is considered a conservation measure that aims to restore the trophic interactions. In north‐central Portugal, the Iberian wolf ( Canis lupus signatus ) is endangered mainly due to human persecution, triggered by wolf depredation on livestock. Several initiatives have occurred in this area to increase wolf wild prey availability by reintroducing/reinforcing roe deer ( Capreolus capreolus ) populations. However, the success of trophic rewilding initiatives relies on up‐to‐date scientific evidence, considering both ecological and social settings. Favorability models can be used to infer the most suitable habitats for roe deer settlement and expansion by analyzing the environmental variables known to influence species ecology and behavior. In this study, we infer how the prey habitat favorability can contribute to plan prey populations reinforcement processes as a tool for trophic chain restoration. Using 330 camera traps, we monitored the roe deer population over 8,940 km 2 in north‐central Portugal. Field data were used to evaluate the environmental determinants of roe deer presence. By using the favorability function, we created a spatially explicit gradient of habitat favorability that allowed us to define key areas for the application of management measures. The selected sites are strategically positioned to promote the natural expansion of established roe deer populations and overlap the current distribution of Iberian wolf. These results are an important step toward the restoration of the trophic chain and to reduce human–wolf conflicts. Our proposal paves the way for future rewilding initiatives, especially where prey species are central to the survival of top predators.

The combination of logging, burning, and livestock farming has been the main driver of European landscape sustainability for thousands of years. Whether or not livestock could keep these habitats on their own is under debate when extensive livestock grazing is kept understory in forests of high environmental value that, in turn, are affected by global warming. In this work, the impact of beef cattle on the diversity, shrub cover, and primary production of the Atlantic Pyrenean oak (Quercus pyrenaica Willd.) in northern Spain has been evaluated. The research studied their feeding habits using the faecal cuticle micro histological analysis in dung samples. Then, the effects of cattle grazing on the cover and alpha diversity of woody plants were evaluated. Finally, oaks’ primary production and phenology in grazed and control areas were compared. The results show that cattle feed on woody (an average of 30% of non-leguminous woody) and annual plant species (more than 20% of forbs) but do not affect plant cover or alpha diversity of vegetation. However, oak phenology differed between grazed and ungrazed treatments, probably due to the spatial variability of grazed forests. It can be concluded that understory grazing in Pyrenean oak forests could be considered a sustainable silvopastoral activity with a neutral impact on forest integrity.

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Context The Mediterranean basin is characterized by a heterogeneous landscape historically shaped by human activities. Land abandonment and extensive monocultures, however, have led to increasing homogeneity of Mediterranean habitats. Albeit the effects of habitat heterogeneity on wildlife have been widely studied, the available information on how habitat homogenization impacts the organization of mesocarnivore communities is still scant. Objectives We investigated the relationship of environmental characteristics with occupancy, activity, community organization, and co-occurrence of mesocarnivore species in space and time. We focused on five key species ( Vulpes vulpes , Genetta genetta , Meles meles , Herpestes ichneumon , and Martes foina ) widely distributed throughout Mediterranean ecosystems. Methods The study was conducted in north-central Portugal between June 2019 and June 2020. We used 300 camera trap sampling points coupled with occupancy, activity, and co-occurrence analysis to assess how different environmental characteristics influence mesocarnivores community. Results We found that the occupancy of mesocarnivores is influenced by topography, landscape composition and structure, and human activity. We observed that landscape homogeneity limits the co-occurrence of mesocarnivores. In heterogeneous landscapes we recorded a greater overlap in activity (seven of ten species pairs) and spatial co-occurrence (six of the seven species pairs analyzed) of mesocarnivores species. Conclusions We demonstrated the importance of landscape characteristics in the composition of the mesocarnivores community. Our findings support the adoption of management measures able to mitigate the impacts of landscape homogenization. Maximizing the heterogeneity is an important step to benefit the mesocarnivore community in altered Iberian landscapes.

Livestock depredation is a common cause of human-carnivore conflicts. In Portugal, free-ranging dogs are increasingly abundant and overlap endangered Iberian wolf territories, with reports of livestock depredation. However, the lack of awareness about dogs’ possible role as predators leads to bias against wolves in cases of damages. Our goal was to assess and compare wolf and free-ranging dog’s diet composition at southern wolf range in Portugal, to offer insights on dogs’ predatory role on livestock and its implications for the conservation of an endangered wolf subpopulation. We assessed diet composition from 107 to 95 genetically confirmed wolf and dog scats, respectively, and complemented the analysis with data from 40 attacks on livestock with successful genetic predator assignment. Scat analysis highlighted goats as the most consumed dog prey in all analysed regions, with lagomorphs, small mammals, and wild boars as second most consumed in each region, respectively. Wolves mainly relied on goats and wild boars in the west, whereas in the central region they mostly fed on birds. The dietary overlap between both canids was very high (Pianka’s index O = 0.93), showing potential for competition. Additionally, we found that dogs were the sole predators detected in most attacks (62%). Our findings highlight dogs’ role as predators of livestock, and possibly also wild species, posing a further challenge to wolf conservation. Alongside adequate husbandry practices, we emphasise the need for a stronger enforcement of the legislation on dog ownership and an effective management of the stray population to reduce human-wolf conflict.

Abstract Background There is need of information on ecological interactions that keystone species such as apex predators establish in ecosystems recently recolonised. Interactions among carnivore species have the potential to influence community-level processes, with consequences for ecosystem dynamics. Although avoidance of apex predators by smaller carnivores has been reported, there is increasing evidence that the potential for competitive-to-facilitative interactions is context-dependent. In a protected area recently recolonised by the wolf Canis lupus and hosting abundant wild prey (3 ungulate species, 20–30 individuals/km2, together), we used 5-year food habit analyses and 3-year camera trapping to (i) investigate the role of mesocarnivores (4 species) in the wolf diet; (ii) test for temporal, spatial, and fine-scale spatiotemporal association between mesocarnivores and the wolf. Results Wolf diet was dominated by large herbivores (86% occurrences, N = 2201 scats), with mesocarnivores occurring in 2% scats. We collected 12,808 carnivore detections over > 19,000 camera trapping days. We found substantial (i.e., generally ≥ 0.75, 0–1 scale) temporal overlap between mesocarnivores—in particular red fox—and the wolf, with no support for negative temporal or spatial associations between mesocarnivore and wolf detection rates. All the species were nocturnal/crepuscular and results suggested a minor role of human activity in modifying interspecific spatiotemporal partitioning. Conclusions Results suggest that the local great availability of large prey to wolves limited negative interactions towards smaller carnivores, thus reducing the potential for spatiotemporal avoidance. Our study emphasises that avoidance patterns leading to substantial spatiotemporal partitioning are not ubiquitous in carnivore guilds.

Mammals are threatened worldwide, with ~26% of all species being included in the IUCN threatened categories. This overall pattern is primarily associated with habitat loss or degradation, and human persecution for terrestrial mammals, and pollution, open net fishing, climate change, and prey depletion for marine mammals. Mammals play a key role in maintaining ecosystems functionality and resilience, and therefore information on their distribution is crucial to delineate and support conservation actions. MAMMALS IN PORTUGAL is a publicly available data set compiling unpublished georeferenced occurrence records of 92 terrestrial, volant, and marine mammals in mainland Portugal and archipelagos of the Azores and Madeira that includes 105,026 data entries between 1873 and 2021 (72% of the data occurring in 2000 and 2021). The methods used to collect the data were: live observations/captures (43%), sign surveys (35%), camera trapping (16%), bioacoustics surveys (4%) and radiotracking, and inquiries that represent less than 1% of the records. The data set includes 13 types of records: (1) burrows | soil mounds | tunnel, (2) capture, (3) colony, (4) dead animal | hair | skulls | jaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8), observation in shelters, (9) photo trapping | video, (10) predators diet | pellets | pine cones/nuts, (11) scat | track | ditch, (12) telemetry and (13) vocalization | echolocation. The spatial uncertainty of most records ranges between 0 and 100 m (76%). Rodentia (n =31,573) has the highest number of records followed by Chiroptera (n = 18,857), Carnivora (n = 18,594), Lagomorpha (n = 17,496), Cetartiodactyla (n = 11,568) and Eulipotyphla (n = 7008). The data set includes records of species classified by the IUCN as threatened (e.g., Oryctolagus cuniculus [n = 12,159], Monachus monachus [n = 1,512], and Lynx pardinus [n = 197]). We believe that this data set may stimulate the publication of other European countries data sets that would certainly contribute to ecology and conservation-related research, and therefore assisting on the development of more accurate and tailored conservation management strategies for each species. There are no copyright restrictions; please cite this data paper when the data are used in publications.

The mechanisms of interactions among carnivore species range from facilitation (mainly through increased availability of prey carcasses) to competition. We assessed the potential for facilitative/competitive interactions between the two most widespread carnivores in the world, the wolf and the red fox, in a prey-rich area recently recolonized by the apex predator. One could expect that the superior competitor would ecologically suppress the inferior one, leading to avoidance of the former by the latter. In a Mediterranean coastal area (2017–2018), we assessed spatiotemporal and dietary interspecific overlap and investigated whether the recovery of wolves affected food habits of foxes. Spatiotemporal overlap was extensive (0.84–0.89). Wild ungulates were the staple of the wolf diet (~88–90%); foxes used mainly invertebrates and fruits (~78%), with ungulates being a substantial food category (13% of diet; 66% of occurrences among vertebrate prey). Interspecific dietary overlap was low (0.23), but extensive (0.89) for vertebrate prey. In comparison to a preceding wolf-free period, the volume and occurrence of large mammals in the diet of foxes showed a 2.8- to 3.5-fold increase. Apparently, foxes did not avoid wolves, which provided additional food to the foxes as prey leftovers. In a rich community, the presence of wolves may increase the food spectrum of foxes. Temporal variation of facilitation vs. competition should be assessed in relationship to spatiotemporal changes of predator–prey numbers.