Giovanni StronaEuropean Commission | ec
Giovanni Strona
Ph.D.
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168
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Introduction
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September 2011 - June 2013
Publications
Publications (168)
A well-known problem in numerical ecology is how to recombine presence-absence matrices without altering row and column totals. A few solutions have been proposed, but all of them present some issues in terms of statistical robustness (that is, their capability to generate different matrix configurations with the same probability) and their perform...
Complex ecological networks appear robust to primary extinctions, possibly due to consumers' tendency to specialize on dependable (available and persistent) resources. However, modifications to the conditions under which the network has evolved might alter resource dependability. Here, we ask whether adaptation to historical conditions can increase...
Significance
Although oil palm cultivation represents an important source of income for many tropical countries, its future expansion is a primary threat to tropical forests and biodiversity. In this context, and especially in regions where industrial palm oil production is still emerging, identifying “areas of compromise,” that is, areas with high...
Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolation and reduced anthropogenic disturbance may incr...
Although theory identifies co-extinctions as a main driver of biodiversity loss, their role at the planetary scale has yet to be estimated. We subjected a global model of interconnected terrestrial vertebrate food webs to future (2020–2100) climate and land-use changes. We predict a 17.6% (± 0.16% SE) average reduction of local vertebrate diversity...
Rectangular association matrices with binary (0/1) entries are a common data structure in many research fields. Examples include ecology, economics, mathematics, physics, psychometrics, and others. Because their columns and rows are associated to distinct entities, these matrices can be equivalently expressed as bipartite networks that, in turn, ca...
Coral restoration plays a pivotal role in mitigating the decline of coral reefs, increasing the need for implementing effective techniques and methodologies. This study investigates the efficacy of stocking Acropora muricata and Pocillopora grandis using fishing line versus rope in mid‐water floating nurseries, offering valuable insights for coral...
The diversity and distribution of traits in an ecological community determine how it functions. Modern fish communities conserve trait space across similar habitats. However, little is known about trait-space variation through deep time. We examined two Devonian fish communities - a tropical reef (Gogo, Australia) and a tropical estuary (Miguasha,...
Although many studies predict extensive future biodiversity loss and redistribution in the terrestrial realm, future changes in marine biodiversity remain relatively unexplored. In this work, we model global shifts in one of the most important marine functional groups—ecosystem-structuring macrophytes—and predict substantial end-of-century change....
Protection from direct human impacts can safeguard marine life, yet ocean warming crosses marine protected area boundaries. Here, we test whether protection offers resilience to marine heatwaves from local to network scales. We examine 71,269 timeseries of population abundances for 2269 reef fish species surveyed in 357 protected versus 747 open si...
The probability of occurrence of a given species in a target locality and assemblage is conditioned not only by environmental/climatic variables but also by the presence of other species (i.e., species co‐occurrence). This framework, already complex in nature, becomes even more complicated if one considers the functional traits of species that, in...
Two dimensional matrices with binary (0/1) entries are a common data structure in many research fields. Examples include ecology, economics, mathematics, physics, psychometrics and others. Because the columns and rows of these matrices represent distinct entities, they can equivalently be expressed as a pair of bipartite networks that are linked by...
The natural world is under unprecedented and accelerating pressure. Much work on understanding resilience to local and global environmental change has, so far, focussed on ecosystems. However, understanding a system’s behaviour requires knowledge of its component parts and their interactions. Here we call for increased efforts to understand ‘biolog...
Permafrost thawing and the potential ‘lab leak’ of ancient microorganisms generate risks of biological invasions for today’s ecological communities, including threats to human health via exposure to emergent pathogens. Whether and how such ‘time-travelling’ invaders could establish in modern communities is unclear, and existing data are too scarce...
Species interactions play a fundamental role in ecosystems. However, few ecological communities have complete data describing such interactions, which is an obstacle to understanding how ecosystems function and respond to perturbations. Because it is often impractical to collect empirical data for all interactions in a community, various methods ha...
The biosphere is changing rapidly due to human endeavour. Because ecological communities underlie networks of interacting species, changes that directly affect some species can have indirect effects on others. Accurate tools to predict these direct and indirect effects are therefore required to guide conservation strategies. However, most extinctio...
The arrangement of plant species within a landscape influences pollination via changes in pollinator movement trajectories and plant–pollinator encounter rates. Yet the combined effects of landscape composition and pollinator traits (especially specialisation) on pollination success remain hard to quantify empirically.
We used an individual‐based m...
This report describes the maps on tree species distribution routinely produced at Joint Research Centre, and the data sets used to produce them. Its aim is to help those searching for information on forest tree species distribution in Europe and to identify which of the maps might fit their needs, what their strengths and weaknesses are, and what d...
Species interactions play a fundamental role in ecosystems. They affect where species can live, how their population sizes fluctuate through time, and how environmental perturbations cascade through communities. But few ecological communities have complete data describing such interactions, which is an obstacle to understanding how ecosystems funct...
Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species’ positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with c...
Due to the many challenges associated with collecting comprehensive information defining the nature and intensity of pairwise relationships between interacting species, often we have to rely on networks that provide a highly simplified picture of reality. Limitations arise, for example, from using undirected or unweighted links to represent scenari...
A simple way to model co-extinctions in resource–consumer networks (such as host-parasite networks or food webs) is: (i) removing nodes according to a particular criterion (either random or informed); and then, (ii) identifying which other nodes in the network are left without interacting partners (and, hence, doomed to co-extinction). Although int...
Networks offer a convenient model to represent countless real-world situations. The use of networks as a framework to explore ecological complexity has become increasingly popular in the last couple of decades. The study of food webs, which has a long history in ecology, has been complemented by a partially distinct and entirely novel research fiel...
The world is collapsing at breakneck speed. The detrimental effects of human presence and activities are so widespread that finding “naturalness” is becoming more challenging every day. This calls for the fundamental question of whether we can halt or, at least, slow down this process. From a pessimistic yet realistic perspective, we have to recogn...
The structure of interactions between species within a community plays a key role in maintaining biodiversity. Previous studies found that the effects of these structures might vary substantially depending on interaction type, for example, a highly connected and nested architecture stabilizes mutualistic communities, while the stability of antagoni...
Coral restoration initiatives are gaining significant momentum in a global effort to enhance the recovery of degraded coral reefs. However, the implementation and upkeep of coral nurseries are particularly demanding, so that unforeseen breaks in maintenance operations might jeopardize well established projects. In the last two years, the COVID‐19 p...
We present “EU-Trees4F”, a dataset of current and future potential distributions of 67 tree species in Europe at 10 km spatial resolution. We provide both climatically suitable future areas of occupancy and the future distribution expected under a scenario of natural dispersal for two emission scenarios (RCP 4.5 and RCP 8.5) and three time steps (2...
Network theory offers innovative tools to explore the complex ecological mechanisms regulating species associations and interactions. Although interest in ecological networks has grown steadily during the last two decades, the application of network approaches has been unequally distributed across different study systems: while some kinds of intera...
Smallholder farmers are some of the poorest and most food insecure people on Earth. Their high nutritional and economic reliance on home‐grown produce makes them particularly vulnerable to environmental stressors such as pollinator loss or climate change which threaten agricultural productivity. Improving smallholder agriculture in a way that is en...
Each species on Earth is linked to all other species by an elusive net of ecological interactions. This means that any extinction might affect to some degree of other species. Yet, conservation tends to focus on species—especially charismatic ones-instead of ecological processes. This attitude is problematic, as it might lead to disregarding critic...
Species dispersal ability has played a lead role in millions of years of evolutionary, biogeographical and ecological processes, eventually leading to modern communities. However, the increasing global mobility is now boosting the frequency of events where species are translocated to localities far beyond their natural dispersal range. For the larg...
The previous chapters have focused on the direct effects of resource loss on consumers. From that perspective, co-extinction events occur (either locally or globally) whenever a consumer runs out of resources, such as in the case of a plant left with no pollinators, a parasite left with no hosts, or a predator left with no prey. However, such direc...
Intuitively a consumer who relies on a limited set of resources for survival would be more at risk of going co-extinct than a generalist capable of using multiple resources. This simple idea contrasts with the fact that specialization is widespread in the natural world (e.g. most parasite species can use just one or a few hosts). The paradox can be...
Differently from previous mass extinct events identifying the main culprits of the ongoing diversity loss is relatively straightforward. We kill animals, we destroy habitats, we pollute the environment, we promote biological invasions. And, of course, we fuel global warming. These mechanisms are not the only ones behind the ongoing Sixth Mass Extin...
The rapid technological development is generating unprecedented opportunities for scientific research. In particular, the development of artificial intelligence (AI) techniques, with computers becoming increasingly independent in performing tasks and—to a certain degree—taking decisions, is opening new frontiers. Machine learning techniques are now...
This book provides, for the first time, a comprehensive overview of the fundamental roles that ecological interactions play in extinction processes, bringing to light an underground of hidden pathways leading to the same dark place: biodiversity loss.
We are in the midst of the sixth mass extinction. We see species declining and vanishing one after...
The ecological concept of “nestedness” has been initially formulated in the context of biogeography and conservation biology, referring, in particular, to non-random distribution patterns of species within a set of localities. There, nestedness quantifies the tendency for the species composition of a community to be a subset of any other species-ri...
Many organisms have complex life cycles characterized by multiple, substantially different stages of development. Often, different stages depend on different resources and are characterized by a different degree of specificity. There are various potential selective advantages associated with a complex life cycle. For example, in the case of trophic...
The direct pressures exerted by global change and human activity on global biodiversity—alteration of local environmental conditions, habitat destruction, mass and selective killing of individuals—account for only one part of the current biodiversity crisis. Increasing theoretical and empirical evidence supports the idea that secondary (co-) extinc...
Simulating progressive, multiple species extinctions in ecological networks while keeping track of the network’s response to subsequent species loss can be an informative exercise. However, the nature of the information emerging from such exercise strongly depends on the identity of nodes (species) removed from the network and the order in which we...
Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. Bottom–up cascades occur when changes in the primary producers in a network elicit flow‐on effects to higher trophic levels. However, it remains unclear what determines a species' vulnerability to bottom–up cascades and whether such cascades were a larg...
An integrated approach using morphological and genetic data is needed to disentangle taxonomic uncertainties affecting the hydrozoan families Sphaerocorynidae and Zancleopsidae. Here we used this approach to accurately characterise species in these families, identify the previously unknown polyp stages of the genera Euphysilla and Zancleopsis, whic...
Significance
Species loss can weaken the trophic interactions that underpin ecosystem functioning. Coral reefs are the world’s most diverse marine ecosystem, harboring interaction networks of extraordinary complexity. We show that, despite this complexity, global coral reef food webs are governed by a suite of highly consistent energetic pathways,...
Reef fishes are a treasured part of marine biodiversity, and also provide needed protein for many millions of people. Although most reef fishes might survive projected increases in ocean temperatures, corals are less tolerant. A few fish species strictly depend on corals for food and shelter, suggesting that coral extinctions could lead to some sec...
Wildfires represent an important factor in the disturbance in Mediterranean ecosystems, although the effects of wildfires on the insect communities of mountain environments remain largely unknown. This research investigated the effect of fire on dung beetles in a Mediterranean high-altitude area, located in Central Italy (1500m elevation). Sampling...
Marginal areas of rice production have the potential to meet increasing oil palm demand in India, without sacrificing forests and associated biodiversity.
The causes of Sahul’s megafauna extinctions remain uncertain, although several interacting factors were likely responsible. To examine the relative support for hypotheses regarding plausible ecological mechanisms underlying these extinctions, we constructed the first stochastic, age-structured models for 13 extinct megafauna species from five funct...
The species–area relationship (SAR) describes a range of related phenomena that are fundamental to the study of biogeography, macroecology and community ecology. While the subject of ongoing debate for a century, surprisingly, no previous book has focused specifically on the SAR. This volume addresses this shortfall by providing a synthesis of the...
Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. However, it remains unclear whether trophic cascades were a large contributor to the megafauna extinctions that swept across several continents in the Late Pleistocene. The pathways to megafauna extinctions are particularly unclear for Sahul (landmass c...
Understanding species’ roles in food webs requires an accurate assessment of their trophic niche. However, it is challenging to delineate potential trophic interactions across an ecosystem, and a paucity of empirical information often leads to inconsistent definitions of trophic guilds based on expert opinion, especially when applied to hyperdivers...
The causes of Sahul’s megafauna extinctions remain uncertain, although multiple, interacting factors were likely responsible. To test hypotheses regarding plausible ecological mechanisms underlying these extinctions, we constructed the first stochastic, age-structured models for 13 extinct megafauna species from five functional/taxonomic groups, as...
Found throughout the tree of life and in every ecosystem, parasites are some of the most diverse, ecologically important animals on Earth—but in almost all cases, the least protected by wildlife or ecosystem conservation efforts. For decades, ecologists have been calling for research to understand parasites' important ecological role, and increasin...
Ecosystems are under unprecedented and accelerating pressures. Much work on understanding resilience to these pressures has, so far, focussed on the ecosystem. However, understanding a system’s behaviour also requires knowledge of its component parts and their interactions. Here we present a framework for understanding ‘biological resilience’, or t...
Accurate delimitation of species and their relationships is a fundamental issue in evolutionary biology and taxonomy and provides essential implications for conservation management. Scleractinian corals are difficult to identify because of their ecophenotypic and geographic variation and their morphological plasticity. Furthermore, phylogenies base...
The diversity of life on our planet has produced a remarkable variety of biological traits that characterize different species. Such traits are widely employed instead of taxonomy to increase our understanding of biodiversity and ecosystem functioning. However, for species’ trophic niches, one of the most critical aspects of organismal ecology, a p...
The concept of generic diversity expresses the ‘diversification’ of species into genera in a community. Since niche overlap is assumed to be higher in congeneric species, competition should increase generic diversity. On the other hand, generic diversity might be lower in highly selective environments, where only species with similar adaptations ca...
Outbreaks of a plant disease in a landscape can be meaningfully modelled using networks with nodes representing individual crop-fields, and edges representing potential infection pathways between them. Their spatial structure, which resembles that of a regular lattice, makes such networks fairly robust against epidemics. Yet, it is well-known how t...
We introduce a suite of software tools aimed at investigating multiple bio-ecological facets of aquatic Groundwater Dependent Ecosystems (GDEs). The suite focuses on: (1) threats posed by pollutants to GDE invertebrates (Ecological Risk, ER); (2) threats posed by hydrological and hydromorphological alterations on the subsurface zone of lotic system...
Aims
Quantifying β‐diversity (differences in the composition of communities) is central to many ecological studies. There are many β‐diversity metrics, falling mostly into two approaches: variance‐based (e.g., the Sørensen index), or diversity partitioning (e.g., additive β‐diversity). The former cannot be used when species–sites matrices are unava...
Recent studies have highlighted the importance of higher‐order competitive interactions in stabilizing population dynamics in multi‐species communities. But how does the structure of competitive hierarchies affect population dynamics and extinction processes? We tackled this important question by using spatially explicit simulations of ecological d...
Climate change and human activity are dooming species at an unprecedented rate via a plethora of direct and indirect, often synergic, mechanisms. Among these, primary extinctions driven by environmental change could be just the tip of an enormous extinction iceberg. As our understanding of the importance of ecological interactions in shaping ecosys...
Europe’s major X. fastidiosa outbreaks have progressed steadily in the past years as data on the bacterial strains causing them, and on the host range and vectors of the pathogen in various regions, became available. The initial uncertainty around these critical epidemiological aspects of the X. fastidiosa invasions hampered estimates of their rate...
The Curveball algorithm is an efficient and unbiased procedure for randomizing bipartite networks (or their matrix counterpart) while preserving node degrees. Here we introduce two extensions of the procedure, making it capable to randomize also unimode directed and undirected networks. We provide formal mathematical proofs that the two extensions,...
A network analysis has been developed exploiting WiFi localization technique. The paper demonstrates how the use of Wi-Fi localization techniques to build high-resolution contact networks is highly relevant for various aspects of global security; for example, in the case of public event people flow monitoring can be analyzed and how a specific even...