## Journal Articles

### 2019

• Bottom-Up Approaches to Synthetic Cooperation in Microbial Communities
D. Rodríguez Amor and M. Dal Bello
Life, Vol. 9, no. 1, 2019

Microbial cooperation pervades ecological scales, from single-species populations to host-associated microbiomes. Understanding the mechanisms promoting the stability of cooperation against potential threats by cheaters is a major question that only recently has been approached experimentally. Synthetic biology has helped to uncover some of these basic mechanisms, which were to some extent anticipated by theoretical predictions. Moreover, synthetic cooperation is a promising lead towards the engineering of novel functions and enhanced productivity of microbial communities. Here, we review recent progress on engineered cooperation in microbial ecosystems. We focus on bottom-up approaches that help to better understand cooperation at the population level, progressively addressing the challenges of tackling higher degrees of complexity: spatial structure, multispecies communities, and host-associated microbiomes. We envisage cooperation as a key ingredient in engineering complex microbial ecosystems.

@article{Rodriguez2019Life,
author = {Rodríguez Amor, Daniel and Dal Bello, Martina},
title = {Bottom-Up Approaches to Synthetic Cooperation in Microbial Communities},
journal = {Life},
volume = {9},
year = {2019},
number = {1},
article-number = {22},
url = {http://www.mdpi.com/2075-1729/9/1/22},
issn = {2075-1729},
doi = {10.3390/life9010022}
}

• Temporal clustering of extreme climate events drives a regime shift in rocky intertidal biofilms
M. Dal Bello, L. Rindi, and L. Benedetti-Cecchi
Ecology, Vol. 100, no. 2, pp. e02578, 2019

Research on regime shifts has focused primarily on how changes in the intensity and duration of press disturbances precipitate natural systems into undesirable, alternative states. By contrast, the role of recurrent pulse perturbations, such as extreme climatic events, has been largely neglected, hindering our understanding of how historical processes regulate the onset of a regime shift. We performed field manipulations to evaluate whether combinations of extreme events of temperature and sediment deposition that differed in their degree of temporal clustering generated alternative states in rocky intertidal epilithic microphytobenthos (biofilms) on rocky shores. The likelihood of biofilms to shift from a vegetated to a bare state depended on the degree of temporal clustering of events, with biofilm biomass showing both states under a regime of non-clustered (60 d apart) perturbations while collapsing in the clustered (15 d apart) scenario. Our results indicate that time since the last perturbation can be an important predictor of collapse in systems exhibiting alternative states and that consideration of historical effects in studies of regime shifts may largely improve our understanding of ecosystem dynamics under climate change.

@article{DalBello2019Ecology,
author = {Dal Bello, Martina and Rindi, Luca and Benedetti-Cecchi, Lisandro},
title = {Temporal clustering of extreme climate events drives a regime shift in rocky intertidal biofilms},
journal = {Ecology},
volume = {100},
number = {2},
pages = {e02578},
keywords = {abrupt changes, alternative states, biofilm, climate change, epilithic microphytobenthos, extreme events, regime shift, temporal clustering},
doi = {10.1002/ecy.2578},
url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2578},
eprint = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecy.2578},
year = {2019}
}


### 2018

• Attraction to pheromones in Caenorhabditis elegans can be reversed through associative learning
M. Dal Bello, A. Pérez-Escudero, F. C. Schroeder, and J. Gore
bioRxiv, Dec. 2018

Despite the ubiquity and importance of chemical signaling, we have only limited insight about the role of learning in the response to pheromones. Here, we demonstrate that responses to pheromones can be reprogrammed through associative learning. In particular, we show that attraction to ascaroside pheromones in the model nematode Caenorhabditis elegans can be reversed by training the animals to associate either a pheromone blend or single synthetic ascarosides with the lack of food. This behavioral plasticity alters worm preference for pheromones following consumption of a food patch, possibly improving foraging in natural environments. By bridging the gap between the current knowledge on the chemical language and the learning abilities of C. elegans, we provide insight on the possible links between learning and chemical signaling in animals.

@article{DalBello2018BioRxiv,
author = {Dal Bello, Martina and P{\'e}rez-Escudero, Alfonso and Schroeder, Frank C and Gore, Jeff},
title = {Attraction to pheromones in Caenorhabditis elegans can be reversed through associative learning},
elocation-id = {476648},
year = {2018},
month = dec,
doi = {10.1101/476648},
publisher = {Cold Spring Harbor Laboratory},
url = {https://www.biorxiv.org/content/early/2018/11/26/476648},
journal = {bioRxiv}
}

• Hybrid datasets: integrating observations with experiments in the era of macroecology and big data
L. Benedetti-Cecchi, F. Bulleri, M. Dal Bello, E. Maggi, C. Ravaglioli, and L. Rindi
Ecology, Vol. 99, no. 12, pp. 2654-2666, 2018

Understanding how increasing human domination of the biosphere affects life on earth is a critical research challenge. This task is facilitated by the increasing availability of open-source data repositories, which allow ecologists to address scientific questions at unprecedented spatial and temporal scales. Large datasets are mostly observational, so they may have limited ability to uncover causal relations among variables. Experiments are better suited at attributing causation, but they are often limited in scope. We propose hybrid datasets, resulting from the integration of observational with experimental data, as an approach to leverage the scope and ability to attribute causality in ecological studies. We show how the analysis of hybrid datasets with emerging techniques in time series analysis (Convergent Cross-mapping) and macroecology (Joint Species Distribution Models) can generate novel insights into causal effects of abiotic and biotic processes that would be difficult to achieve otherwise. We illustrate these principles with two case studies in marine ecosystems and discuss the potential to generalize across environments, species and ecological processes. If used wisely, the analysis of hybrid datasets may become the standard approach for research goals that seek causal explanations for large-scale ecological phenomena.

@article{BenedettiCecchi2018Ecology,
author = {Benedetti-Cecchi, Lisandro and Bulleri, Fabio and Dal Bello, Martina and Maggi, Elena and Ravaglioli, Chiara and Rindi, Luca},
title = {Hybrid datasets: integrating observations with experiments in the era of macroecology and big data},
journal = {Ecology},
volume = {99},
number = {12},
pages = {2654-2666},
keywords = {causality, convergent cross-mapping, distributed experiments, empirical dynamic modelling, hybrid dataset approach, macroecology, species distribution models, time series},
doi = {10.1002/ecy.2504},
url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2504},
eprint = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecy.2504},
year = {2018}
}

• Experimental evidence of spatial signatures of approaching regime shifts in macroalgal canopies
L. Rindi, M. Dal Bello, and L. Benedetti-Cecchi
Ecology, Vol. 99, no. 8, pp. 1709-1715, 2018

Developing early warning signals to predict regime shifts in ecosystems is a central issue in current ecological research. While there are many studies addressing temporal early warning indicators, research into spatial indicators is far behind, with field experiments even more rare. Here, we tested the performance of spatial early warning signals in an intertidal macroalgal system, where removal of algal canopies pushed the system toward a tipping point (corresponding to approximately 75% of canopy loss), marking the transition between a canopy- to a turf-dominated state. We performed a two-year experiment where spatial early warning indicators were assessed in transects where the canopy was differentially removed (from 0 to 100%). Unlike Moran correlation coefficient at lag-1, spatial variance, skewness, and spatial spectra at low frequency increased along the gradient of canopy degradation and dropped, or did not show any further increase beyond the transition point from a canopy- to a turf-dominated state (100% canopy removal). Our study provides direct evidence of the suitability of spatial early warning signals to anticipate regime shifts in natural ecosystems, emphasizing the importance of field experiments as a powerful tool to establish causal relationships between environmental stressors and early warning indicators.

@article{Rindi2018Ecology,
author = {Rindi, L. and Dal Bello, M. and Benedetti-Cecchi, L.},
title = {Experimental evidence of spatial signatures of approaching regime shifts in macroalgal canopies},
journal = {Ecology},
volume = {99},
number = {8},
pages = {1709-1715},
keywords = {algal turfs, alternative states, canopy–turf transition, early warning signals, macroalgal canopies, regime shift, resilience, spatial ecology, spatial variance},
doi = {10.1002/ecy.2391},
url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.2391},
year = {2018}
}

• The role of wave-exposure and human impacts in regulating the distribution of alternative habitats on NW Mediterranean rocky reefs
F. Bulleri, A. Cucco, M. D. Bello, E. Maggi, C. Ravaglioli, and L. Benedetti-Cecchi
Estuarine, Coastal and Shelf Science, Vol. 201, pp. 114 - 122, 2018

The global decline of canopy-forming macroalgae has stimulated research on the mechanism regulating shifts among alternative habitats on rocky reefs. The effects of sea urchin grazing and alterations of environmental conditions are now acknowledged as the main drivers of shifts between canopy-formers and encrusting coralline barrens and algal turfs, respectively. The conditions under which these mechanisms operate remains, however, somewhat elusive. This is mostly a consequence of the fact that our current understanding has been generated by envisioning habitat shifts as dichotomic, at odds with rocky reef landscapes being composed by mosaics of habitats and with evidence of strong interactions among the species that compose each of the alternative habitats. Using data from a long-term sampling program and path analysis, we investigated how wave-exposure and human-induced degradation of environmental conditions regulate the mechanisms maintaining algal canopies formed by Cystoseira crinita, barren habitats and algal turfs as alternative states on subtidal reefs in the NW Mediterranean. In the Tuscan Archipelago, wave-exposure had positive effects on sea urchins, which, likely due to their low mean density, had weak effects on each of the alternative habitats. Canopy-forming macroalgae resulted, instead, to exert strong negative effects on the abundance of algal turfs. Since data from the Tuscan Archipelago did not explain any of the variation in the abundance of C. crinita canopies, a further analysis was performed including data from the coast of Tuscany to assess the role of cumulative human impacts in regulating habitat shifts. This showed that degradation of environmental conditions is a direct cause of the decline of macroalgal canopies, indirectly favouring the dominance of algal turfs. Our study suggests that management of human impacts should be considered a priority for preserving subtidal canopies formed by Cystoseira in the NW Mediterranean and that conservation efforts based exclusively on the control of sea urchin populations might be doomed to failure in some areas.

@article{Bulleri2018ECSS,
title = {The role of wave-exposure and human impacts in regulating the distribution of alternative habitats on NW Mediterranean rocky reefs},
journal = {Estuarine, Coastal and Shelf Science},
volume = {201},
pages = {114 - 122},
year = {2018},
note = {Vectors of change in the marine environment},
issn = {14},
doi = {https://doi.org/10.1016/j.ecss.2016.02.013},
url = {http://www.sciencedirect.com/science/article/pii/S0272771416300567},
author = {Bulleri, Fabio and Cucco, Andrea and Bello, Martina Dal and Maggi, Elena and Ravaglioli, Chiara and Benedetti-Cecchi, Lisandro},
keywords = {Alternative habitats, Rocky shores, Algae, Grazing, Anthropogenic stressors, Mediterreanean, Tuscan Archipelago}
}


### 2017

• Spatio-temporal variability in Mediterranean rocky shore microphytobenthos
E. Maggi, L. Rindi, M. Dal Bello, D. Fontanini, A. Capocchi, L. Bongiorni, and L. Benedetti-Cecchi
Marine Ecology Progress Series, Vol. 575, pp. 17–29, Jul. 2017

Knowledge of spatio-temporal variability of assemblages is the first step in identifying key factors affecting the abundance and distribution of organisms. Despite a long history of ecological studies on rocky intertidal habitats, there is still a lack of basic knowledge about the microphytobenthic components. We investigated the spatio-temporal variability of microphytobenthos in the northwest Mediterranean at multiple scales, including both seasonal and daily observations, as well as its composition. Spatial variability of microphytobenthic biomass varied significantly with season, with an increase in small-scale variance from cold to warm periods. Furthermore, during warmer months, small-scale variances (tens to hundreds of centimeters) were larger than large-scale components (tens to thousands of meters). These results suggest large spatio-temporal variation in the processes driving variation in microphytobenthic assemblages, including interactive effects among stressful abiotic conditions, substratum topography and grazing. In addition, observed variability on a daily scale suggested that microphytobenthos at the study site (dominated by cyanobacteria) might cope with stressful environmental conditions through both physiological and behavioral strategies at micro-spatial scales, including small movements within the substratum. Additional research on ecological and physiological aspects of rocky shore microphytobenthos is needed to better understand its role within interaction webs and primary productivity processes.

@article{Maggi2017MEPS,
author = {Maggi, E and Rindi, L and {Dal Bello}, M and Fontanini, D and Capocchi, A and Bongiorni, L and Benedetti-Cecchi, L},
doi = {10.3354/meps12216},
issn = {01718630},
journal = {Marine Ecology Progress Series},
keywords = {Bacterial diversity,Daily variation,Mediterranean Sea,Microphytobenthos,Rocky shore,Spatio-temporal variability},
month = jul,
pages = {17--29},
title = {Spatio-temporal variability in Mediterranean rocky shore microphytobenthos},
url = {http://www.int-res.com/abstracts/meps/v575/p17-29/},
volume = {575},
year = {2017}
}

• Direct observation of increasing recovery length before collapse of a marine benthic ecosystem
L. Rindi, M. D. Bello, L. Dai, J. Gore, and L. Benedetti-Cecchi
Nature Ecology & Evolution, Vol. 1, no. 6, pp. 0153, May. 2017

Ecosystems can experience catastrophic transitions to alternative states, yet recent results have suggested that slowing down in rates of recovery after a perturbation may provide advance warning that a critical transition is approaching. Perturbation experiments with microbial populations have supported this hypothesis under controlled laboratory conditions, but evidence from natural ecosystems remains rare. Here, we manipulated rocky intertidal canopy algae to test the hypothesis that the spatial scale at which the system recovers from a perturbation in space should increase as the system approaches the tipping point, marking the transition from a canopy-dominated to a turf-dominated state. Empirical estimates of recovery length, a recently proposed spatial indicator of an approaching tipping point, were obtained by comparing the spatial scale at which algal turfs propagated into canopy-degraded regions with decreasing canopy cover. We show that recovery length increased along the gradient in canopy degradation, providing field-based evidence of spatial signatures of critical slowing down in natural conditions.

@article{Rindi2017NEE,
author = {Rindi, Luca and Bello, Martina Dal and Dai, Lei and Gore, Jeff and Benedetti-Cecchi, Lisandro},
doi = {10.1038/s41559-017-0153},
issn = {2397-334X},
journal = {Nature Ecology {\&} Evolution},
keywords = {Ecology,Marine biology},
month = may,
number = {6},
pages = {0153},
publisher = {Nature Publishing Group},
title = {Direct observation of increasing recovery length before collapse of a marine benthic ecosystem},
url = {http://www.nature.com/articles/s41559-017-0153},
volume = {1},
year = {2017},
prize = {Science},
}

• Legacy effects and memory loss: how contingencies moderate the response of rocky intertidal biofilms to present and past extreme events
M. Dal Bello, L. Rindi, and L. Benedetti-Cecchi
Global Change Biology, Vol. 23, no. 8, pp. 3259-3268, 2017

Understanding how historical processes modulate the response of ecosystems to perturbations is becoming increasingly important. In contrast to the growing interest in projecting biodiversity and ecosystem functioning under future climate scenarios, how legacy effects originating from historical conditions drive change in ecosystems remains largely unexplored. Using experiments in combination with stochastic antecedent modelling, we evaluated how extreme warming, sediment deposition and grazing events modulated the ecological memory of rocky intertidal epilithic microphytobenthos (EMPB). We found memory effects in the non-clustered scenario of disturbance (60 days apart), where EMPB biomass fluctuated in time, but not under clustered disturbances (15 days apart), where EMPB biomass was consistently low. A massive grazing event impacted on EMPB biomass in a second run of the experiment, also muting ecological memory. Our results provide empirical support to the theoretical expectation that stochastic fluctuations promote ecological memory, but also show that contingencies may lead to memory loss.

@article{DalBello2017GCB,
author = {Dal Bello, Martina and Rindi, Luca and Benedetti-Cecchi, Lisandro},
title = {Legacy effects and memory loss: how contingencies moderate the response of rocky intertidal biofilms to present and past extreme events},
journal = {Global Change Biology},
volume = {23},
number = {8},
pages = {3259-3268},
keywords = {antecedent conditions, biofilm, ecological memory, epilithic microphytobenthos, extreme climatic events, grazing, hierarchical Bayesian model, legacy effects, temporal clustering},
doi = {10.1111/gcb.13656},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13656},
year = {2017}
}

• Consistent patterns of spatial variability between NE Atlantic and Mediterranean rocky shores
M. Dal Bello, J.-C. Leclerc, L. Benedetti-Cecchi, G. Andrea De Lucia, C. Arvanitidis, P. Van Avesaath, G. Bachelet, N. Bojanic, S. Como, S. Coppa, and et al.
Journal of the Marine Biological Association of the United Kingdom, Vol. 97, no. 3, pp. 539–547, 2017

Examining how variability in population abundance and distribution is allotted among different spatial scales can inform of processes that are likely to generate that variability. Results of studies dealing with scale issues in marine benthic communities suggest that variability is concentrated at small spatial scales (from tens of centimetres to few metres) and that spatial patterns of variation are consistent across ecosystems characterized by contrasting physical and biotic conditions, but this has not been formally tested. Here we quantified the variability in the distribution of intertidal rocky shore communities at a range of spatial scales, from tens of centimetres to thousands of kilometres, both in the NE Atlantic and the Mediterranean, and tested whether the observed patterns differed between the two basins. We focused on canopy-forming macroalgae and associated understorey assemblages in the low intertidal, and on the distribution of Patella limpets at mid intertidal levels. Our results highlight that patterns of spatial variation, at each scale investigated, were consistent between the Atlantic and the Mediterranean, suggesting that similar ecological processes operate in these regions. In contrast with former studies, variability in canopy cover, species richness and limpet abundance was equally distributed among spatial scales, possibly reflecting the fingerprint of multiple processes. Variability in community structure of low intertidal assemblages, instead, peaked at the largest scale, suggesting that oceanographic processes and climatic gradients may be important. We conclude that formal comparisons of variability across scales nested in contrasting systems are needed, before any generalization on patterns and processes can be made.

@article{DalBello2017JMBAUK,
title = {Consistent patterns of spatial variability between NE Atlantic and Mediterranean rocky shores},
url = {https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/consistent-patterns-of-spatial-variability-between-ne-atlantic-and-mediterranean-rocky-shores/77D18C4C86B0227CE921FEDEC9D0A675},
volume = {97},
doi = {10.1017/S0025315416001491},
number = {3},
journal = {Journal of the Marine Biological Association of the United Kingdom},
publisher = {Cambridge University Press},
author = {Dal Bello, Martina and Leclerc, Jean-Charles and Benedetti-Cecchi, Lisandro and Andrea De Lucia, Giuseppe and Arvanitidis, Christos and Van Avesaath, Pim and Bachelet, Guy and Bojanic, Natalia and Como, Serena and Coppa, Stefania and et al.},
year = {2017},
pages = {539–547}
}

• The role of physical variables in biodiversity patterns of intertidal macroalgae along European coasts
A. Puente, X. Guinda, J. A. Juanes, M. ... Dal Bello, and et al.
Journal of the Marine Biological Association of the United Kingdom, Vol. 97, no. 3, pp. 549–560, 2017

In the frame of the COST ACTION ‘EMBOS’ (Development and implementation of a pan-European Marine Biodiversity Observatory System), coverage of intertidal macroalgae was estimated at a range of marine stations along the European coastline (Subarctic, Baltic, Atlantic, Mediterranean). Based on these data, we tested whether patterns in macroalgal diversity and distribution along European intertidal rocky shores could be explained by a set of meteo-oceanographic variables. The variables considered were salinity, sea surface temperature, photosynthetically active radiation, significant wave height and tidal range and were compiled from three different sources: remote sensing, reanalysis technique and in situ measurement. These variables were parameterized to represent average conditions (mean values), variability (standard deviation) and extreme events (minimum and maximum values). The results obtained in this study contribute to reinforce the EMBOS network approach and highlight the necessity of considering meteo-oceanographic variables in long-term assessments. The broad spatial distribution of pilot sites has allowed identification of latitudinal and longitudinal gradients manifested through species composition, diversity and dominance structure of intertidal macroalgae. These patterns follow a latitudinal gradient mainly explained by sea surface temperature, but also by photosynthetically active radiation, salinity and tidal range. Additionally, a longitudinal gradient was also detected and could be linked to wave height.

@article{Puente2017JMBAUK,
title = {The role of physical variables in biodiversity patterns of intertidal macroalgae along European coasts},
url = {https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/role-of-physical-variables-in-biodiversity-patterns-of-intertidal-macroalgae-along-european-coasts/35FF88CC36A85F01E5A8B52AA9A2FE4F},
volume = {97},
doi = {10.1017/S0025315416001673},
number = {3},
journal = {Journal of the Marine Biological Association of the United Kingdom},
publisher = {Cambridge University Press},
author = {Puente, Araceli and Guinda, Xabier and Juanes, Jose A. and ... Dal Bello, Martina and et al.},
year = {2017},
pages = {549–560}
}

• Essence of the patterns of cover and richness of intertidal hard bottom communities: a pan-European study
J. Kotta, H. Orav-Kotta, H. Jänes, M. ... Dal Bello, and et al.
Journal of the Marine Biological Association of the United Kingdom, Vol. 97, no. 3, pp. 525–538, 2017

Coastal ecosystems are highly complex and driven by multiple environmental factors. To date we lack scientific evidence for the relative contribution of natural and anthropogenic drivers for the majority of marine habitats in order to adequately assess the role of different stressors across the European seas. Such relationship can be investigated by analysing the correlation between environmental variables and biotic patterns in multivariate space and taking into account non-linearities. Within the framework of the EMBOS (European Marine Biodiversity Observatory System) programme, hard bottom intertidal communities were sampled in a standardized way across European seas. Links between key natural and anthropogenic drivers and hard bottom communities were analysed using Boosted Regression Trees modelling. The study identified strong interregional variability and showed that patterns of hard bottom macroalgal and invertebrate communities were primarily a function of tidal regime, nutrient loading and water temperature (anomalies). The strength and shape of functional form relationships varied widely however among types of organisms (understorey algae composing mostly filamentous species, canopy-forming algae or sessile invertebrates) and aggregated community variables (cover or richness). Tidal regime significantly modulated the effect of nutrient load on the cover and richness of understorey algae and sessile invertebrates. In contrast, hydroclimate was more important for canopy algae and temperature anomalies and hydroclimate separately or interactively contributed to the observed patterns. The analyses also suggested that climate-induced shifts in weather patterns may result in the loss of algal richness and thereby in the loss of functional diversity in European hard bottom intertidal areas.

@article{Kotta2017JMBAUK,
title = {Essence of the patterns of cover and richness of intertidal hard bottom communities: a pan-European study},
url = {https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/essence-of-the-patterns-of-cover-and-richness-of-intertidal-hard-bottom-communities-a-paneuropean-study/9DBCE02834F2CD347E6BE03198066E2D},
volume = {97},
doi = {10.1017/S0025315416001351},
number = {3},
journal = {Journal of the Marine Biological Association of the United Kingdom},
publisher = {Cambridge University Press},
author = {Kotta, Jonne and Orav-Kotta, Helen and Jänes, Holger and ... Dal Bello, Martina and et al.},
year = {2017},
pages = {525–538}
}

• Geographic patterns of biodiversity in European coastal marine benthos
H. Hummel, P. Van Avesaath, S. Wijnhoven, M. ... Dal Bello, and et al.
Journal of the Marine Biological Association of the United Kingdom, Vol. 97, no. 3, pp. 507–523, 2017

Within the COST action EMBOS (European Marine Biodiversity Observatory System) the degree and variation of the diversity and densities of soft-bottom communities from the lower intertidal or the shallow subtidal was measured at 28 marine sites along the European coastline (Baltic, Atlantic, Mediterranean) using jointly agreed and harmonized protocols, tools and indicators. The hypothesis tested was that the diversity for all taxonomic groups would decrease with increasing latitude. The EMBOS system delivered accurate and comparable data on the diversity and densities of the soft sediment macrozoobenthic community over a large-scale gradient along the European coastline. In contrast to general biogeographic theory, species diversity showed no linear relationship with latitude, yet a bell-shaped relation was found. The diversity and densities of benthos were mostly positively correlated with environmental factors such as temperature, salinity, mud and organic matter content in sediment, or wave height, and related with location characteristics such as system type (lagoons, estuaries, open coast) or stratum (intertidal, subtidal). For some relationships, a maximum (e.g. temperature from 15–20°C; mud content of sediment around 40%) or bimodal curve (e.g. salinity) was found. In lagoons the densities were twice higher than in other locations, and at open coasts the diversity was much lower than in other locations. We conclude that latitudinal trends and regional differences in diversity and densities are strongly influenced by, i.e. merely the result of, particular sets and ranges of environmental factors and location characteristics specific to certain areas, such as the Baltic, with typical salinity clines (favouring insects) and the Mediterranean, with higher temperatures (favouring crustaceans). Therefore, eventual trends with latitude are primarily indirect and so can be overcome by local variation of environmental factors.

@article{Hummel2017JMBAUK,
title = {Geographic patterns of biodiversity in European coastal marine benthos},
url = {https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/geographic-patterns-of-biodiversity-in-european-coastal-marine-benthos/34E1ACF08EF157D9007AACBC1FF63114},
volume = {97},
doi = {10.1017/S0025315416001119},
number = {3},
journal = {Journal of the Marine Biological Association of the United Kingdom},
publisher = {Cambridge University Press},
author = {Hummel, Herman and Van Avesaath, Pim and Wijnhoven, Sander and ... Dal Bello, Martina and et al.},
year = {2017},
pages = {507–523}
}


### 2015

• Effects of grazer diversity on marine microphytobenthic biofilm: a ‘tug of war’ between complementarity and competition
C. Sanz-Lázaro, E. Maggi, L. Rindi, M. Dal Bello, and L. Benedetti-Cecchi
Marine Ecology Progress Series, Vol. 540, pp. 145–155, Nov. 2015

Species loss is one of the most striking problems related to human-driven environmental changes. Nevertheless, biodiversity and ecosystem functioning experiments have mainly focused on primary producers, paying less attention to the consequences of changing diversity at higher trophic levels. We performed a field experiment using cage enclosures to test the effects of species richness, identity and density of gastropod grazers on the photosynthetic efficiency and biomass of intertidal biofilm on an exposed rocky shore in the northwest Mediterranean. The diversity and composition of intertidal grazers affected the photosynthetic efficiency of biofilm with only negligible effects on biomass. Individual species showed strong identity effects. In assemblages of 2 or more species, positive or negative complementarity effects occurred. The magnitude of the ecosystem response is expected to depend on the particular species assemblage and its density, which will determine whether niche partitioning or competition is the prevailing process. Grazer preference in specific components of biofilm, characterized by different photosynthetic efficiency and competitive abilities, might explain concomitant changes in photosynthetic efficiency and comparable levels in biomass among treatments. The effects of grazers declined following the natural trend of decreasing biomass of biofilm during the study period, highlighting the importance of considering temporal variability in the effects of biodiversity on ecosystem functioning. This work emphasizes the key role of species identity to predict effects on their resources and ecosystem functioning.

@article{SanzLazaro2015MEPS,
author = {Sanz-L{\'{a}}zaro, Carlos and Maggi, Elena and Rindi, Luca and Dal Bello, Martina and Benedetti-Cecchi, Lisandro},
doi = {10.3354/meps11507},
issn = {0171-8630},
journal = {Marine Ecology Progress Series},
keywords = {Biodiversity and ecosystem functioning,Density-dependent effects,Intertidal,Limpet,Patella sp.,Photosynthetic efficiency,Temporal heterogeneity,Topshell},
month = nov,
pages = {145--155},
title = {Effects of grazer diversity on marine microphytobenthic biofilm: a ‘tug of war' between complementarity and competition},
url = {http://www.int-res.com/abstracts/meps/v540/p145-155/},
volume = {540},
year = {2015}
}

• Multifractal spatial distribution of epilithic microphytobenthos on a Mediterranean rocky shore
M. Dal Bello, E. Maggi, L. Rindi, A. Capocchi, D. Fontanini, C. Sanz-Lazaro, and L. Benedetti-Cecchi
Oikos, Vol. 124, no. 4, pp. 477-485, 2015

Understanding how patterns and processes relate across spatial scales is one of the major goals in ecology. 1/f models have been applied mostly to time series of environmental and ecological variables, but they can also be used to analyse spatial patterns. Since 1/f noise may display scale-invariant behaviour, ecological phenomena whose spatial variability shows 1/f type scaling are susceptible to further characterization using fractals or multifractals. Here we use spectral analysis and multifractal techniques (generalized dimension spectrum) to investigate the spatial distribution of epilithic microphytobenthos (EMPB) on rocky intertidal surfaces. EMPB biomass was estimated from calibrated colour-infrared images that provided indirect measures of rock surface chlorophyll a concentration, along two 8-m and one 4-m long transects sampled in January and November 2012. Results highlighted a pattern of spectral coefficient close to or greater than one for EMPB biomass distribution and multifractal structures, that were consistent among transects, implying scale-invariance in the spatial distribution of EMPB. These outcomes can be interpreted as a result of the superimposition of several biotic and abiotic processes acting at multiple spatial scales. However, the scale-invariant nature of EMPB spatial patterns can also be considered a hallmark of self-organization, underlying the possible role of scale-dependent feedback in shaping EMPB biomass distribution.

@article{DalBello2015Oikos,
author = {Dal Bello, Martina and Maggi, Elena and Rindi, Luca and Capocchi, Antonella and Fontanini, Debora and Sanz-Lazaro, Carlos and Benedetti-Cecchi, Lisandro},
title = {Multifractal spatial distribution of epilithic microphytobenthos on a Mediterranean rocky shore},
journal = {Oikos},
volume = {124},
number = {4},
pages = {477-485},
doi = {10.1111/oik.01503},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.01503},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/oik.01503},
year = {2015}
}


## Theses

### 2014

• The coincidence of environmental and climatic extremes and the response of primary producers in marine coastal habitats and open systems
M. Dal Bello
University of Pisa, Apr. 2014

Understanding how global change affects primary productivity in natural systems is of crucial importance. The majority of ecological studies on climate change focused the attention on the impact of mean changes in environmental conditions, but there is increasing evidence indicating that ecological responses may depend as much upon environmental variation and extremes. Extreme weather events, such as severe droughts, heavy rainfalls, heat waves and hot spells, are increasing in severity and frequency and are likely to cause severe impacts at all levels of biological organization. So far, most manipulative field experiments have examined the effects of individual extreme events, with little attention to the possible synergistic effects of multiple extreme disturbances. My thesis addresses the need to examine the combined effects of compounded extreme events on natural population. I focused on phytoplankton and intertidal epilithic microphytobenthos (EMPB) biofilms as model systems. EMPB has been used to test the hypothesis that the concomitance of distinct environmental extreme events elicits larger effects compared to the expected cumulative effect of individual extreme events. The importance of stochastic and determinist environmental changes in driving extreme events has been evaluated through the environmental bootstrap method applied at the scale of the Mediterranean basin. Research on biofilms started from basic descriptions of spatial organization, as understanding these patterns is necessary to interpret the effects of climate extremes. Results indicated that microalgae develop scale-invariant structures, reflecting the influence of multiple processes operating at different spatial scales and possibly self-organization. A manipulative experiment was set up in order to test the separate and combined effects of warming and runoff following heavy rainfalls. Although a general pattern of reduced EMPB biomass in the clustered than the non-clustered scenario emerged in the first trial of the experiment, the hypothesis that compounded extreme events would elicit larger impacts than extremities of individual disturbances was not supported. EMPB biomass was susceptible to both warming and runoff, but the effects of the combination of these stressors was complex and context-dependent. Thus, repeating this experiment at different times will be necessary before generalities about EMPB responses to environmental extremes can be drawn. The environmental bootstrap method resampled short-term data of sea surface temperature and patterns of geostrophic currents to obtain an ensemble of hypothetical time series that, when combined with a predictive model of chlorophyll a concentration allowed me to make inferences on primary productivity response to environmental extremes. The output of this analysis is a map of the distribution of chlorophyll a concentration values with 100 years return time periods for the Mediterranean basin, which highlights the areas that are likely to harbour exceptional greening events.

@phdthesis{DalBello2014,
author = {Dal Bello, Martina},
keywords = {phytoplankton, multifractal analysis, global change, extreme events, epilithic microphytobenthos, environmental bootstrap method, spectral analysis},
month = apr,
school = {University of Pisa},
title = {The coincidence of environmental and climatic extremes and the response of primary producers in marine coastal habitats and open systems},
year = {2014}
}


### 2010

• Influenza dell’eterogeneità ambientale nella valutazione dell’effetto riserva: il caso dei popolamenti ittici dell’Arcipelago Toscano
M. Dal Bello
University of Pisa, Oct. 2010

@mastersthesis{DalBello2010,
author = {Dal Bello, Martina},
month = oct,
school = {University of Pisa},
title = {Influenza dell'eterogeneità ambientale nella valutazione dell'effetto riserva: il caso dei popolamenti ittici dell'Arcipelago Toscano},