Biology subjects

Maiorano, L.

Publications and source records attributed to Maiorano, L..

10 recordsLinked to original sources

bioRxiv2025

Tracking community change via network coherence

Understanding how ecological communities respond to environmental change remains a key challenge for biodiversity monitoring. To characterize such responses, we need tools that capture how coherently species respond across a community, and to predict their consequences, we must account for ecological interactions. We first introduce the Ecological Coherence (EC) framework, which describes how species co-responses are structured within a community. Building on this foundation, we extend it to Ecological Network Coherence (ENC), which embeds co-responses within the network of interactions by restricting them to interacting species. Both are expressed through two complementary representations: a response correlation matrix and the distribution of its values. The first can reveal aspects such as coherent or incoherent modules and the roles species play in shaping coherence, whereas the second provides a profile whose shape may serve as an early-warning indicator of instability. These can be applied to both intrinsic responses (environmental performance) and realized responses (abundance dynamics), derived from currently available monitoring data. We illustrate this approach in two empirical systems: a tropical pollination network, where interacting mutualists were more coherent in their temperature responses than the broader community, and a marine food web, where coherence in abundance trends shifted during collapse. Using a Lotka-Volterra model, we further show that ENC distributions with higher variance--reflecting stronger positive and negative co-responses--increase the risk of instability or amplification in dynamics. We also find that species influential in both the correlation matrix and the interaction matrix are key drivers of major dynamic shifts. These results point to the importance of further exploring ENC distributions as potential early-warning indicators of ecological disruption.

ecology↗

bioRxiv2025

Threats to Nature's Contributions to People provided by terrestrial vertebrates across Europe

Aim.Species and ecosystem processes offer essential benefits to people, known as Natures Contributions to People (NCP). However, we still lack a comprehensive understanding of NCP provided by terrestrial vertebrates on a large scale, and of the threats they face. To bridge this gap, we built a comprehensive dataset that documents the NCP provided by terrestrial vertebrate species in Europe, and analysed the conservation status and threats to NCP provider species. Location.Europe Methods.We synthesised existing literature on NCP associated with European terrestrial vertebrates, and leveraged ecological traits and trophic interactions from previously established datasets. We identified 15 NCP (10 regulating NCP and 5 non-material NCP), with 860 species providing at least one NCP (out of 1,168 vertebrate species considered in total). Then, we harnessed species distribution data and a novel European land system map to create species-mediated NCP maps across Europe at a 1km{superscript 2} resolution, including societal demand for each NCP. Results.We found that i) for each NCP, at least 25% of NCP provider species are assessed as threatened with extinction; ii) NCP multifunctionality is lowest in high-intensity land systems; and iii) direct exploitation and agricultural intensification are major threats to species-mediated NCP, impacting both non-material and regulating NCP provider species. Main conclusions.Protecting threatened NCP provider species, and reducing direct exploitation are key to maintain regulating and non-material NCP. Our results suggest that de-intensifying agricultural practices, through maintaining heterogeneous mosaic landscapes and promoting diversified practices, could increase NCP multifunctionality. Our work enables a comprehensive understanding of NCP provided by terrestrial vertebrates in Europe, their biogeography, and the threats they face, which can in turn inform spatial conservation planning to improve the conservation of both biodiversity and NCP.

ecology↗

bioRxiv2024

Human footprint and forest disturbance reduce space use of brown bears across Europe.

Three-quarters of the planets land surface has been altered by humans, with consequences for animal ecology, movements and related ecosystem functioning. Species often occupy wide geographical ranges with contrasting human disturbance and environmental conditions, yet, limited data availability across species ranges has constrained our understanding of how human impact and resource availability jointly shape intraspecific variation of animal space use. Leveraging a unique dataset of 752 annual GPS movement trajectories from 370 brown bears (Ursus arctos) across the species range in Europe, we investigated the effects of human impact (i.e., human footprint index), resource availability, forest cover and disturbance, and area-based conservation measures on brown bear space use. We quantified space use at different spatio-temporal scales during the growing season (May - September): home range size; representing general space requirements, 10-day long-distance displacement distances, and routine 1-day displacement distances. We found large intraspecific variation in brown bear space use across all scales, which was profoundly affected by human footprint index, vegetation productivity, and recent forest disturbances creating opportunity for resource pulses. Bears occupied smaller home ranges and moved less in more anthropized landscapes and in areas of higher resource availability. Forest disturbances reduced space use while contiguous forest cover promoted longer daily movements. The amount of strictly protected and roadless areas within bear home ranges were too small to affect space use. Anthropized landscapes may hinder the expansion of small and isolated populations, such as the Apennine and Pyrenean, and obstruct population connectivity, for example between the Alpine or Carpathian with the Dinaric Pindos populations. Our findings call for actions to maintain bear movements across landscapes with high human footprint, for example by maintaining forest integrity, to support viable bear populations and their ecosystem functions.

ecology↗

bioRxiv2024

Shaping the Future: the importance of land use when projecting the future distribution of Endangered Amphibians and Reptiles.

Obtaining reliable predictions of future species distributions under global change scenarios is fundamental for identifying priority conservation sites. This requires incorporating the main drivers of distribution shifts into the modeling process. Climate change and land use change are the two primary drivers of species distributions, yet they have been considered differently in studies exploring future scenarios. Most studies focus solely on bioclimatic variables, given that climate is a major determinant of species distributions on a large spatial scale. In our study, we explored the impact of including dynamic land use variables in species distribution models, examining predicted range loss and spatial mismatch of suitable areas compared to models using only bioclimatic variables. Our findings indicate that including land cover can significantly alter model outputs. While incorporating land use and land cover variables did not enhance the predictive power for most species, it substantially affected the predicted future suitable areas for 60% of the species (mean change = 69%, range: 4% to 167%). This trend was consistent across all spatial resolutions. The two modeling approaches also differed in the spatial location of suitable areas. The level of disagreement varied across species but was generally high for both current and future scenarios, increasing with coarser resolutions. Our results underscore the significant implications of excluding land use change variables and highlight the necessity of considering these factors on a taxon-specific basis.

ecology↗

bioRxiv2024

Keeping common species common: the role of future climate refugee in species conservation

Climate change is one of the most important challenges for biodiversity conservation. Species may respond to changing climates by moving, adapting, and/or adjusting. The move response is the easiest and quickest as it does not imply any evolutionary and/or physiological response. However, moving in space to track changing climate is not an option for species with restricted movement capacities (e.g., many amphibians) or species endemic to islands. Therefore, the impact of climate change on these species is potentially dramatic, even when they are currently widespread and least concern. Planning for the conservation of these species in a global change context requires a proactive approach, with the identification of climatic refugia, i.e., areas climatically suitable for a given species under both current climate and future scenarios. Here, we demonstrated our approach considering the Hyla sarda, an amphibian endemic of the islands of Sardinia and Corsica, currently widespread in its range, and Least Concern according to the IUCN Red List. We calibrated an SDM for the species focusing on Sardinia and projected it into the future, identifying all areas that can act as future climatic refugia. We also evaluated the coverage of the refugia by the existing protected areas. According to our results, Hyla sarda will experience a significant restriction of its distribution range due to projected climate changes, with small and highly fragmented climatic refugia mostly located outside of existing protected areas. Our findings highlight the importance of considering common species in global change studies. All our conservation strategies should be more proactive if we want to conserve common species before they become rare.

ecology↗

bioRxiv2023

Including biotic interactions in species distribution models improves the understanding of species niche: a case of study with the brown bear in Europe

Biotic interactions are expected to influence species responses to climate change, but they are usually not included when predicting future range shifts. We assessed the importance of biotic interactions to understand future consequences of climate and land use change for biodiversity using as a model system the brown bear (Ursus arctos) in Europe. By including biotic interactions using the spatial variation of energy contribution and habitat models of each food species, we showed that the use of biotic factors considerably improves our understanding of the distribution of brown bears. Predicted future range shifts, which included changes in the distribution of food species, varied greatly when considering various scenarios of change in biotic factors, warning about future indirect climate change effects. Our study confirmed that advancing our understanding of ecological networks of species interactions will improve future scenarios of biodiversity change, which is key for conserving biodiversity and ecosystem services.

ecology↗

bioRxiv2020

Assessing the reliability of species distribution projections in climate change research

AimForecasting changes in species distribution under future scenarios is one of the most prolific areas of application for species distribution models (SDMs). However, no consensus yet exists on the reliability of such models for drawing conclusions on species distribution response to changing climate. In this study we provide an overview of common modelling practices in the field and assess model predictions reliability using a virtual species approach. LocationGlobal MethodsWe first provide an overview of common modelling practices in the field by reviewing the papers published in the last 5 years. Then, we use a virtual species approach and three commonly applied SDM algorithms (GLM, MaxEnt and Random Forest) to assess the estimated (cross-validated) and actual predictive performance of models parameterized with different modelling settings and violations of modelling assumptions. ResultsOur literature review shows that most papers that model species distribution under climate change rely on single models (65%) and small samples (< 50 presence points, 62%), use presence-only data (85%), and binarize models output to estimate range shift, contraction or expansion (74%). Our virtual species approach reveals that the estimated predictive performance tends to be over-optimistic compared to the real predictive performance. Further, the binarization of predicted probabilities of presence reduces models predictive ability considerably. Sample size is one of the main predictors of real accuracy, but has little influence on estimated accuracy. Finally, the inclusion of irrelevant predictors and the violation of modelling assumptions increases estimated accuracy but decreases real accuracy of model projections, leading to biased estimates of range contraction and expansion. Main conclusionsOur study calls for extreme caution in the application and interpretation of SDMs in the context of biodiversity conservation and climate change research, especially when modelling a large number of species where species-specific model settings become impracticable.

ecology↗

bioRxiv2020

Drivers of change in the realised climatic niche of terrestrial mammal species

The breadth of a species climatic niche is an important ecological trait that allows adaptation to climate change, but human activities drive niche erosion. Life-history traits, such as dispersal ability and reproductive speed, instead allow species to cope with climate change. But how do these characteristics act in combination with human pressure to determine niche change? Here we investigate the patterns and drivers of change in the realised climatic niche of 589 terrestrial mammal species. Our goal is to disentangle the impacts of humans, climate change, and life history. We calibrated the past and present climatic niches of each species by considering past climatic conditions (Mid Holocene) within their pre-human impact distributions, and current climatic conditions within the current distributions. Depending on the relationship between past and current niche, we defined four categories of change: "shrink", "shift", "stable", and "expand". We found over half of the species in our sample have undergone niche shrink, while only 15-18% of species retained a stable niche. After controlling for biogeography, climatic factors were the strongest correlates of species niche change, followed by anthropogenic pressure and species life history. Factors that increased the probability of niche shrink include: overall climatic instability in the area (both intermediate or high), large body mass, long gestation time, highly carnivorous or herbivorous diets, historical land-use change, and current human population density. We identified the conditions under which species are less likely to maintain their niche breadth, potentially losing adaptation capacity under climate change. Species with these characteristics require interventions that facilitate natural dispersal or assisted colonisation, to survive to rapidly changing climates.

ecology↗

bioRxiv2018

Drilling down hotspots of intraspecific diversity to bring them into on-ground conservation of threatened species

Unprecedented rates of biodiversity loss rise the urgency for preserving species ability to cope with ongoing global changes. An approach in this direction is to target intra-specific hotspots of genetic diversity as conservation priorities. However, these hotspots are often identified by sampling at a spatial resolution too coarse to be useful in practical management of threatened species, hindering the long-appealed dialog between conservation stakeholders and conservation genetic researchers. Here, we investigated the spatial and temporal variation in species presence, genetic diversity, as well as potential risk factors, within a previously identified hotspot of genetic diversity for the endangered Apennine yellow bellied toad Bombina pachypus. Our results show that this hotspot is neither a geographically homogeneous nor a temporally stable unit. Over a time-window spanning 10-40 years since previous assessments, B. pachypus populations declined in large portions of its hotspot, and their genetic diversity levels decreased. Considering the demographic trend, genetic and epidemiological data, and models of current and future climatic suitability, populations at the extreme south of the hotspot area still qualify for urgent in-situ conservation actions, whereas northern populations would be better managed through a mix of in-situ and ex-situ actions. Our results emphasize that identifying hotspot of genetic diversity, albeit essential step, does not suffice to warrant on-ground conservation of threatened species. Hotspots should be analysed at finer geographic and temporal scales, to provide conservation stakeholders with key knowledge to best define conservation priorities, and to optimize resource allocation to alternative management practices.

evolutionary biology↗

bioRxiv2016

Climate change promotes hybridisation between deeply divergent species of European toads

Rare hybridisations between deeply divergent animal species have been reported for decades in a wide range of taxa, but have often remained unexplained, mainly considered chance events and reported as anecdotal. Here, we combine field observations with long-term data concerning natural hybridizations, climate, land-use, and field-validated species distribution models for two deeply divergent and naturally sympatric toad species in Europe (Bufo bufo and Bufotes viridis species groups). We show that climate warming and seasonal extreme temperatures are conspiring to set the scene for these maladaptive hybridisations, by differentially affecting life-history traits of both species. Our results identify and provide evidence of an ultimate cause for such events, and reveal that the potential influence of climate change on interspecific hybridisations goes far beyond closely related species. Furthermore, climate projections suggest that the chances for these events will steadily increase in the near future.

evolutionary biology↗