publications | Xavier Benito-Granell

2026

Environmental drivers of freshwater diatom assemblages in island streams: insights from the Canary Archipelago

Paula Mendoza-Casanova, Xavier Benito, Raúl Acosta, and 5 more authors

2026

DOI
River oligotrophication under global change: A systematic review of long-term nutrient trends and biological responses

Nguyễn Vũ {}textbackslash}DJức Thịnh, Camille Minaudo, Xavier Benito, and 2 more authors

2026

2025

Biodiversity and spatial distribution of potentially ciguatera-causing dinoflagellates using DNA metabarcoding

Rosa Trobajo, Javier Pérez-Burillo, Sandra Gimeno-Monforte, and 5 more authors

2025
OLIGOTREND, a global database of multi-decadal chlorophyll \textita and water quality time series for rivers, lakes, and estuaries

Camille Minaudo, Andras Abonyi, Carles Alcaraz, and 8 more authors

2025

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Reversed eutrophication, called oligotrophication, has been widely documented globally over the last 30 years in rivers, lakes, and estuaries. However, the absence of a comprehensive and harmonized dataset has hindered a deeper understanding of its ecological consequences. To address this data gap, we developed the OLIGOTREND database, which contains multi-decadal time series of chlorophyll a, nutrients (nitrogen and phosphorus), and related physicochemical parameters, totalling 4.3 million observations. These data originate from 1894 unique monitoring locations across estuaries (n = 238), lakes (687), and rivers (969). Most time series cover the period from 1986–2022 and comprise at least 15 years of chlorophyll a observations. Each location is associated with catchment and hydroclimatic attributes. Trend and breakpoint analyses were applied to all time series. Chlorophyll a showed temporally variable and ecosystem-specific responses to nutrient declines with an overall declining trend for 18 % of the time series, contrasting greatly with a majority of declining trends for nutrient concentrations. We harmonized the database to ensure reproducibility and ease of access and support future updates and contributions. Available at https://doi.org/10.6073/pasta/a7ad060a4dbc4e7dfcb763a794506524 (Minaudo and Benito, 2024), the OLIGOTREND database supports collaborative efforts aimed at further advancing our understanding of biogeochemical and biological mechanisms underlining oligotrophication and ecological impacts of global long-term environmental change.
Origins and history of human impact related to land use in Latin America

Paula Echeverría-Galindo, Xavier Benito, Julieta Massaferro, and 1 more author

Past Global Changes Magazine, Apr 2025

DOI

2024

Oligotrend, a global database of multi-decadal timeseries of chlorophyll-a and nutrient concentrations in inland and transitional waters, 1986-2023

Camille Minaudo and Xavier Benito-Granell

Apr 2024

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The Oligotrend database is a collection of multi-decadal chlorophyll-a and nutrient timeseries in inland and transitional waters. The objective of this Data Package was to explore how inland and transitional aquatic ecosystems respond to oligotrophication trends. Overall, the Oligotrend L1 database is made of 4.3 million valid observations originating from 1,894 stations. There are 238, 687 and 969 stations located in estuaries, lakes and rivers, respectively. The top 3 largest sources of data are the French national water quality monitoring (775 stations), the global database of lake datasets from Naderian et al. 2024 (378 stations), and the Chesapeake Bay Program (199 stations). The data was harmonized through a reproducible data processing pathway. In this Data Package, quality-checked level 1 data is provided, together with data sources, geographical coordinates of the stations, and the output of a trend analysis of all timeseries.
Ten simple rules to bridge ecology and palaeoecology by publishing outside palaeoecological journals

Nick Schafstall, Xavier Benito, Sandra O. Brugger, and 19 more authors

PLOS Computational Biology, Oct 2024

Publisher: Public Library of Science

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Owing to its specialised methodology, palaeoecology is often regarded as a separate field from ecology, even though it is essential for understanding long-term ecological processes that have shaped the ecosystems that ecologists study and manage. Despite advances in ecological modelling, sample dating, and proxy-based reconstructions facilitating direct comparison of palaeoecological data with neo-ecological data, most of the scientific knowledge derived from palaeoecological studies remains siloed. We surveyed a group of palaeo-researchers with experience in crossing the divide between palaeoecology and neo-ecology, to develop Ten Simple Rules for publishing your palaeoecological research in non-palaeo journals. Our 10 rules are divided into the preparation phase, writing phase, and finalising phase when the article is submitted to the target journal. These rules provide a suite of strategies, including improved networking early in the process, building effective collaborations, transmitting results more efficiently to improve cross-disciplinary accessibility, and integrating concepts and methodologies that appeal to ecologists and a wider readership. Adhering to these Ten Simple Rules can ensure palaeoecologists’ findings are more accessible and impactful among ecologists and the wider scientific community. Although this article primarily shows examples of how palaeoecological studies were published in journals for a broader audience, the rules apply to anyone who aims to publish outside specialised journals.
Planktic diatom responses to spatiotemporal environmental variation in high‐mountain tropical lakes

Melina Luethje, Pablo V. Mosquera, Henrietta Hampel, and 2 more authors

Freshwater Biology, Jan 2024

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Abstract Tropical lakes harbour high levels of biodiversity, but the temporal and spatial variability of biological communities are still inadequately characterised, making it difficult to predict the impact of accelerated rates of environmental change in these regions. Our goal was to identify the spatiotemporal dynamics of the planktic diatom community in the Cajas Massif in the tropical Andes. We analysed seasonal diatom and environmental data over a period of 1 year from 10 lakes located in geologically distinct basins and modelled community–environment relationships using multivariate ordination and variation partitioning techniques. Generalised additive models with a full‐subset information theoretic approach also were used to determine which environmental variables explain single‐species abundance. Although the lakes are monomictic and thus have variable thermal structure across the year, seasonal variability of water chemistry conditions was negligible, and seasonal differences in diatom community composition were small. Across space, diatom community composition was correlated primarily with ionic content (divalent cations and alkalinity), related to bedrock composition, and secondly with lake thermal structure and productivity. The ionic gradient overrode the effect of the thermal structure–productivity gradient at the diatom community level, whereas individual diatom species responded more sensitively to variables related to in‐lake and catchment productivity, including chlorophyll‐ a and iron, and the proportion of wetlands in the catchment. Our results indicate that the spatiotemporal variability of Cajas lakes and their diatom communities is the result of multiple intertwined environmental factors. The emergence of the ionic and thermal structure–productivity gradients in a rather small tropical lake district suggests segregation of ecological niches for diatoms that also may be important in other high‐elevation lake regions. Future studies that track tropical Andean lakes under natural and anthropogenically mediated change, both in contemporary times and in palaeoenvironmental reconstructions, would benefit from the modelling approach (community and species levels) developed here.

2023

Ecosystem-level effects of re-oligotrophication and N:P imbalances in rivers and estuaries on a global scale

Carles Ibáñez, Nuno Caiola, José Barquín, and 10 more authors

Global Change Biology, Jan 2023

_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.16520

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Trends and ecological consequences of phosphorus (P) decline and increasing nitrogen (N) to phosphorus (N:P) ratios in rivers and estuaries are reviewed and discussed. Results suggest that re-oligotrophication is a dominant trend in rivers and estuaries of high-income countries in the last two–three decades, while in low-income countries widespread eutrophication occurs. The decline in P is well documented in hundreds of rivers of United States and the European Union, but the biotic response of rivers and estuaries besides phytoplankton decline such as trends in phytoplankton composition, changes in primary production, ecosystem shifts, cascading effects, changes in ecosystem metabolism, etc., have not been sufficiently monitored and investigated, neither the effects of N:P imbalance. N:P imbalance has significant ecological effects that need to be further investigated. There is a growing number of cases in which phytoplankton biomass have been shown to decrease due to re-oligotrophication, but the potential regime shift from phytoplankton to macrophyte dominance described in shallow lakes has been documented only in a few rivers and estuaries yet. The main reasons why regime shifts are rarely described in rivers and estuaries are, from one hand the scarcity of data on macrophyte cover trends, and from the other hand physical factors such as peak flows or high turbidity that could prevent a general spread of submerged macrophytes as observed in shallow lakes. Moreover, re-oligotrophication effects on rivers may be different compared to lakes (e.g., lower dominance of macrophytes) or estuaries (e.g., limitation of primary production by N instead of P) or may be dependent on river/estuary type. We conclude that river and estuary re-oligotrophication effects are complex, diverse and still little known, and in some cases are equivalent to those described in shallow lakes, but the regime shift is more likely to occur in mid to high-order rivers and shallow estuaries.
Paleolimnological responses of Ecuadorian páramo lakes to local and regional stressors over the last two millennia

Melina Luethje, Xavier Benito, Tobias Schneider, and 3 more authors

Journal of Paleolimnology, Jan 2023

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Increasing surface air temperatures and human influences (e.g., agriculture, livestock grazing, tourism) are altering lacustrine ecosystems in the South American Andean páramo, and these influences are evident in changes in the diatom-species composition in sediment cores from the region that span the last ~ 150 years. Existing studies are limited by their short temporal scales and limited spatial extent. We analyzed two sediment cores spanning the last two millennia from the northern (Laguna Piñan) and southern (Laguna Fondococha) Andean páramo of Ecuador to provide a longer-term perspective on lake dynamics. Both lakes show shifts in the dominant diatoms through time. Fondococha diatoms shifted in dominance between two Aulacoseira species and in the planktic to benthic ratio, and these shifts are interpreted as evidence of changing lake level. The inferred shifts are corroborated by changes in sediment geochemistry. Piñan shows a directional shift in the diatom assemblage over the period of the record, from benthic diatoms tolerant of high dissolved organic carbon (DOC), low pH, and low nutrients, to an assemblage characteristic of lower DOC, higher pH, nutrients and lake levels. Shifts in Piñan’s diatoms are correlated with tephra layers in the sediment, suggesting that local volcanic deposition may have been responsible for altering the catchment and lake geochemistry. This is supported by relatively high δ13C values in organic matter associated with tephra layers, which become more negative up-section. Our study suggests that remote lakes in spatially heterogenous montane regions act as sentinels of different facets of environmental change and provide insights into Andean ecosystem responses to environmental perturbations.
My Teaching Is Not Gender Biased, Is It?

Clara Mendoza-Lera, Maria Anton-Pardo, Mireia Bartrons, and 15 more authors

Limnology and Oceanography Bulletin, Jan 2023

_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/lob.10598

DOI
pSESYNTH project: Community mobilization for a multi-disciplinary paleo database of the Global South

Charuta Kulkarni, I. A. Jara, M. Chevalier, and 1 more author

PAGES magazines, Jan 2023

Publisher: Past Global Changes
Integration of proxies in human–environmental systems: paleoecology, paleoclimatology, and archaeology

Macarena M. Zarza, Xavier Benito, Carola Flores, and 3 more authors

Past global changes magazine: annual records of the past, Jan 2023

Publisher: PAGES International Project Office

2022

Human practices behind the aquatic and terrestrial ecological decoupling to climate change in the tropical Andes

Xavier Benito, Blas Benito, Maria I. Vélez, and 4 more authors

Science of The Total Environment, Jun 2022

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Anthropogenic climate change and landscape alteration are two of the most important threats to the terrestrial and aquatic ecosystems of the tropical Americas, thus jeopardizing water and soil resources for millions of people in the Andean nations. Understanding how aquatic ecosystems will respond to anthropogenic stressors and accelerated warming requires shifting from short-term and static to long-term, dynamic characterizations of human-terrestrial-aquatic relationships. Here we use sediment records from Lake Llaviucu, a tropical mountain Andean lake long accessed by Indigenous and post-European societies, and hypothesize that under natural historical conditions (i.e., low human pressure) vegetation and aquatic ecosystems’ responses to change are coupled through indirect climate influences—that is, past climate-driven vegetation changes dictated limnological trajectories. We used a multi-proxy paleoecological approach including drivers of terrestrial vegetation change (pollen), soil erosion (Titanium), human activity (agropastoralism indicators), and aquatic responses (diatoms) to estimate assemblage-wide rates of change and model their synchronous and asynchronous (lagged) relationships using Generalized Additive Models. Assemblage-wide rate of change results showed that between ca. 3000 and 400 calibrated years before present (cal years BP) terrestrial vegetation, agropastoralism and diatoms fluctuated along their mean regimes of rate of change without consistent periods of synchronous rapid change. In contrast, positive lagged relationships (i.e., asynchrony) between climate-driven terrestrial pollen changes and diatom responses (i.e., asynchrony) were in operation until ca. 750 cal years BP. Thereafter, positive lagged relationships between agropastoralism and diatom rates of changes dictated the lake trajectory, reflecting the primary control of human practices over the aquatic ecosystem prior European occupation. We interpret that shifts in Indigenous practices (e.g., valley terracing) curtailed nutrient inputs into the lake decoupling the links between climate-driven vegetation changes and the aquatic community. Our results demonstrate how rates of change of anthropogenic and climatic influences can guide dynamic ecological baselines for managing water ecosystem services in the Andes.
Ecological resilience in tropical Andean lakes: A paleolimnological perspective

Xavier Benito, Melina Luethje, Tobias Schneider, and 7 more authors

Limnology and Oceanography, Jun 2022

_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11747

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Little is known about whether changes in lake ecosystem structure over the past 150 years are unprecedented when considering longer timescales. Similarly, research linking environmental stressors to lake ecological resilience has traditionally focused on a few sentinel sites, hindering the study of spatially synchronous changes across large areas. Here, we studied signatures of paleolimnological resilience by tracking change in diatom community composition over the last 2000 years in four Ecuadorian Andean lakes with contrasting ecoregions. We focused on climate and anthropogenic change, and the type of biological responses that these changes induced: gradual, elastic, or threshold. We combined multivariate ordination techniques with nonlinear time-series methods (hierarchical generalized additive models) to characterize trajectories of community responses in each lake, and coherence in such trajectories across lakes. We hypothesized that remote, high-elevation lakes would exhibit synchronous trends due to their shared climatic constraints, whereas lower elevation lakes would show less synchronous trends as a consequence of human density and land-cover alteration. We found that gradual and elastic responses dominated. Threshold-type responses, or regime shifts, were only detected in the less remote lake, after a long period of gradual and elastic changes. Unexpected synchrony was observed in diatom assemblages from geographically distant and human-impacted lakes, whereas lakes under similar broad-scale environmental factors (climate and ecoregion) showed asynchronous community trajectories over time. Our results reveal a complex ecological history and indicate that Andean lakes in Ecuador can gradually adapt and recover from a myriad of disturbances, exhibiting resilience over century to millennial timescales.
Tropical South America Diatom Database: a tool for studying the macroecology of microorganisms

Xavier Benito, Melina Feitl, Maria L. Carrevedo, and 5 more authors

Diatom Research, Jun 2022

Publisher: Taylor & Francis _eprint: https://www.tandfonline.com/doi/pdf/10.1080/0269249X.2022.2078429

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Determining the mechanisms of community assembly forms the foundation of biogeography and community ecology. Studies of the biodiversity and distribution of Neotropical macro-organisms have revealed the roles of environmental, spatial, and historical factors in structuring communities at different spatial and temporal scales. The role of these factors for species and communities of microorganisms are still poorly understood. Diatoms are a very species-rich group of algae, widely distributed, and sensitive to environmental variation because of their position at the base of aquatic food webs. Here, we present the Tropical South American Diatom Database (TSADB), which contains geographical and ecological information on diatom species across lentic and lotic environments, including predictors that describe local (limnological) and regional (geo-climatic) factors. The open access database can be used to ask fundamental questions in macroecology, including testing foundational theories of metacommunity ecology and biogeography, and evaluating the sensitivity of species and communities to the rapid environmental changes characteristic of tropical regions. The TSADB includes diatom taxa from 437 samples from 326 sites distributed across 26 regions (0–5,070 m a.s.l, and between 8°N–35°S; 58–90°W). In addition, long-term, diatom-based paleolimnological records are presented as a complementary tool for identifying geographically well-covered regions with modern and palaeo-datasets. We describe the TSADB structure and functionality, together with the R codes for data manipulation and visualization. Each of the 26 study regions is represented by three data matrices: sampling site information, environmental variables (limnology, climate, and landscape), and diatom community data (relative abundance or presence/absence). Access to data and future additions is through publicly available repositories and a guide to contributors, respectively. Thus, it offers ample opportunities to complement existing databases on diatoms, allowing optimal usage of TSADB by scientists including diatomists, limnologists, and aquatic ecologists.
Women in limnology: From a historical perspective to a present-day evaluation

Núria Catalán, Maria Anton-Pardo, Anna Freixa, and 11 more authors

WIREs Water, Jun 2022

_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/wat2.1616

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Research in limnology is nurtured by the work of many fascinating and passionate women, who have contributed enormously to our understanding of inland waters. Female limnologists have promoted and established the bases of our knowledge about inland waters and fostered the need of protecting the values of those ecosystems. However, on numerous occasions, their contribution to the advancement of limnology has not been duly recognized. Here, we review the presence of women in limnology through the history of the discipline: from the pioneers who contributed to the origins to present day’ developments. We aim at visibilizing those scientists and establish them as role models. We also analyze in a simple and illustrative way the current situation of women in limnology, the scientific barriers they must deal with, and their future prospects. Multiple aspects fostering the visibility of a scientist, such as their presence in conferences, awards, or representation in societal or editorial boards show a significant gap, with none of those aspects showing a similar visibility of women and men in limnology. This article raises awareness of the obstacles that women in limnology faced and still face, and encourages to embrace models of leadership, scientific management, and assessment of research performance far from those commonly established. This article is categorized under: Science of Water \textgreater Methods Water and Life \textgreater Methods

2021

Virtual Past Socio-Environmental Systems: An interdisciplinary ECR workshop

X. Benito, I. Jara, G. Camperio, and 7 more authors

Past Global Changes Magazine, May 2021

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2020

Diatom Diversity and Biogeography Across Tropical South America

Xavier Benito and Sherilyn C. Fritz

In Neotropical Diversification: Patterns and Processes, May 2020

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Determining the mechanisms of community assembly forms the foundation of biogeography and community ecology. Studies of the biodiversity of Neotropical macro-organisms have recognized the roles of environmental, spatial, and historical factors in structuring communities at different spatial and temporal scales, but the influences on microorganisms are not well studied. Diatoms (unicellular siliceous algae) are a very species-rich group of algae, disperse widely, and respond rapidly and sensitively to environmental variation. In this chapter, we use a newly constructed database of tropical South American diatoms (8°N–30°S and 58–79°W) to analyze the distribution and diversity patterns of species across lentic and lotic environments, including predictors that describe local (limnology) and regional (geo-climatic) factors. We provide a conceptual framework that examines community responses (species composition and diversity) to environmental and spatial factors by applying paleolimnology and macroecological approaches (Theory of Island of Biogeography and metacommunity theory). Diatom biogeographic patterns emerge for (1) identifying regionally distinct floras with a significant association with geographic groups of lakes, (2) determining latitudinal gradients of species richness and community structure, and (3) estimating the joint contribution of environmental filtering and dispersal dynamics in affecting diatom community composition across time. We emphasize the potential for incorporating diatom ecology and paleolimnology into a macroecology framework to further develop multiple, interdisciplinary hypotheses on the mechanisms driving microbial diversity and community assembly in the Neotropics.
The adoption of agropastoralism and increase in ENSO frequency in the Andes

Majoi N. Nascimento, Nicole Alana Sublette Mosblech, M. F. Raczka, and 6 more authors

Quaternary Science Reviews, May 2020

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Benthic Foraminifera and Diatoms as Ecological Indicators

Xavier Benito

In Modern Trends in Diatom Identification: Fundamentals and Applications, May 2020

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Ecology can be defined as the study of causes that govern the distribution and abundance of organisms and their relation to the environment. Among benthic microorganisms (10 μm–500 mm), diatoms and foraminifera are of great importance in aquatic ecosystems worldwide because (1) their species react in a rapid and sensitive way to environmental changes in water bodies, and (2) they preserve in sediments for a long time due to their shells, which are made of silica (diatoms) or calcium carbonate or cemented detrital material (foraminifera). In shallow coastal ecosystems (coastal lagoons, marshes), these attributes make foraminifera and diatoms extremely valuable for both ecology and geology because modern communities indicate the dynamic transition between terrestrial and marine habitats, and fossil assemblages record past sea-level changes. While many other works provide specific information on the taxonomy, biology, and ecology of foraminifera and diatoms independently, this chapter aims to provide a comprehensive joint perspective of the applications and uses of these two groups of organisms for environmental studies in coastal habitats. Given the ongoing and future threats associated with sea-level rise and water scarcity, and the lack of long-term monitoring data to assess ecosystems’ deviation from natural baseline conditions, palaeoecological applications of foraminifera and diatoms are also discussed in the context of environmental and restoration policies.
Spatial and Temporal Ecological Uniqueness of Andean Diatom Communities Are Correlated With Climate, Geodiversity and Long-Term Limnological Change

Xavier Benito, Annika Vilmi, Melina Luethje, and 3 more authors

Frontiers in Ecology and Evolution, May 2020

Publisher: Frontiers

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High-elevation tropical lakes are excellent sentinels of global change impacts, such as climate warming, land-use change, and atmospheric deposition. These effects are often correlated with temporal and spatial beta diversity patterns, with some local communities contributing more than others, a phenomenon known as local contribution to beta diversity (LCBD) or ecological uniqueness. Microorganisms, such as diatoms, are considered whole-ecosystem indicators but little is known about their sensitivity and specificity in beta diversity studies, mostly because of the lack of large spatial and temporal datasets. To fill this gap, we used a tropical South American diatom database comprising modern (144 lakes) and paleolimnological (6 sediment cores) observations to quantify drivers of spatial and temporal beta diversity and evaluate implications for environmental change and regional biodiversity. We used methods of beta diversity partitioning (replacement and richness components) by determining contributions of local sites to these components (LCBDrepl and LCBDrich), and studied how they are related to environmental, geological, and historical variables using Generalized Additive Models. Beta replacement time series were also analyzed with GAM to test whether there is widespread biotic homogenization across the tropical Andes. Modern lake ecological uniqueness was jointly explained by limnological (pH), climatic (mean annual precipitation), and historical human impacts. Limnological (conductivity) and geodiversity variables (terrain ruggedness, soil variability) were inversely correlated to replacement and richness components of local contribution to beta diversity, suggesting that not all lakes contributing to regional diversity are targets for conservation actions. Over millennial time scales, decomposing temporal trends of beta diversity components showed different trajectories of lake diatom diversity as response of environmental change. This is shown by i) increased hydroclimatic variability (as inferred by decreased temperature seasonality) mediating higher contribution of richness to local beta diversity patterns ca. 1000 years ago in Ecuador Andean lakes; and ii) lake-specific temporal beta diversity trends for the last ca. 200 years, indicating that biotic homogenization is not widespread across the tropical Andes. Our approach for unifying diatom ecology, metacommunity studies, and paleolimnology can facilitate the understanding of future responses of tropical Andean lakes to global change impacts.

2019

Identifying temporal and spatial patterns of diatom community change in the tropical Andes over the last ~150 years

X. Benito, M. Feitl, S. C. Fritz, and 5 more authors

Journal of Biogeography, May 2019

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Basin-scale land use impacts on world deltas: Human vs natural forcings

C. Ibáñez, C. Alcaraz, N. Caiola, and 6 more authors

Global and Planetary Change, May 2019

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A new global database of 86 deltas and river basins was analyzed to investigate the relative importance of deforestation and land use changes versus natural forcings in determining long-term total delta size. Results show that mean river flow and shelf slope were the most important variables, whereas population density and sediment load had a much lower importance. Deforestation and other variables related to land-use generally had a very small effect, but were more influential in a subset comprising Mediterranean and Black Sea deltas. As most deltas have developed over thousands of years, the much shorter-lived anthropogenic signals from deforestation and other landscape perturbations have had only secondary impact on the total area of deltas. Also, delta progradation is strongly influenced on sand deposition, whereas anthropogenic impacts on sediment load have more often impacted mostly the finer sediment being deposited offshore (prodelta deposits) or in the deltaic plain. These data disproves the hypothesis that delta size and growth is strongly influenced by human forcings, particularly for larger deltas, since Holocene delta building is mainly determined by natural forces. However, humans are influencing the geomorphology of deltas, particularly over the last century when the Anthropocene nature of deltas has become manifest. A more precise terminology is proposed to clarify concepts such as “human-made”, “human-engineered” or “human-influenced” deltas.
Long-term and regional perspectives on recent change in lacustrine diatom communities in the tropical Andes

Sherilyn C. Fritz, Xavier Benito, and Miriam Steinitz-Kannan

Journal of Paleolimnology, May 2019

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Understanding and managing the responses of natural systems to climate change requires knowing whether recent changes in ecosystem structure and function are within the bounds of natural variation or whether the systems are entering new states that are unprecedented. Several recent studies of the fossil diatom record of the last ~ 150 years in Andean lakes have shown changes in diatom species composition that suggest changes in lake thermal structure in response to regional climate warming. Yet these paleolimnological records are only a few hundred years in length, so it is unclear whether the systems have entered new states, with potentially severe consequences for ecosystem structure and function, or whether current trends are within the natural variability of the systems. Here, we use a recently compiled diatom database from tropical South America to explore the regional distribution and ecological controls of selected planktic diatom taxa that are associated with warming and changes in the lake thermal structure. We also review published Andean stratigraphic records that span thousands of years to characterize the long-term dynamics of relevant planktic species in response to past climate change. The contemporary data show that many planktic taxa have broad latitudinal and elevational distributions. The distributions of several taxa are correlated with surface water temperature, but most also are correlated with pH and/or conductivity. A review of existing stratigraphic data from Andean lakes demonstrates that rapid changes in diatom abundance, including abrupt increases followed by decades to centuries of near extirpation, are a common mode of population variation for some planktic taxa. Yet the majority of these published paleolimnological investigations are of lakes that are larger and differ in nutrient status and conductivity from the small dilute systems where recent species shifts have been observed. We propose that assessing the resilience of contemporary diatom communities and, by inference, lake ecosystems is best done by generating new records from Andean lakes of varied size and chemistry that span a millennium or more and hence a broader spectrum of climate conditions, coupled with new ecological and biogeographic studies that build upon ongoing research programs in the tropical Andes.
Pristine vs. human-altered Ebro Delta habitats display contrasting resilience to RSLR

Patricia Prado, Carles Alcaraz, Xavier Benito, and 2 more authors

Science of the Total Environment, May 2019

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2018

Aquatic ecosystems in a newly formed ecospace: Early Pliocene lakes in the Central Andean Altiplano

M. I. Vélez, C. Jaramillo, A. Salazar-Ríos, and 6 more authors

Palaeogeography, Palaeoclimatology, Palaeoecology, May 2018

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Geo-climatic factors drive diatom community distribution in tropical South American freshwaters

X. Benito, S. C. Fritz, M. Steinitz-Kannan, and 3 more authors

Journal of Ecology, May 2018

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Data from: Geo-climatic factors drive diatom community distribution in tropical South American freshwaters

X. Benito, S.C. Fritz, M. Steinitz-Kannan, and 3 more authors

Feb 2018

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1.Patterns that maintain and generate biodiversity of macro-organisms in the Neotropics are widely discussed in the scientific literature, yet the spatial ecology of microorganisms is largely unknown. The unique character of the tropical Andes and adjacent Amazon lowlands generates a wide gradient of environmental conditions to advance our understanding of what drives community assembly and diversity processes. 2.We analyzed the distribution patterns of benthic diatoms (unicellular siliceous algae) as a model group of microbial passive dispersers, including predictors that describe limnological and geo-climatic gradients for a total of 113 waterbodies (0–28ºS and 58–80ºW), including lakes and streams. Complementary multivariate statistical analyses were performed to correlate i) community composition, and ii) diatom species richness with environmental and spatial factors to infer niche-based and dispersal-based assembly processes, respectively. 3.Results showed that two gradients structured both diatom assemblages and waterbodies, namely climate and landscape configuration. Variance partitioning revealed that broad-scale spatial variables (distance-based Moran’s Eigenvectors) outperformed the two environmental components (limnological and geo-climatic), suggesting dispersal-assembled communities. However, diatom assemblages were structured by geo-climatic (regional) factors in certain lakes in the northern and central Andes, although their effects were partially manifested via local variables after the geographical distances were factored out. In a similar way, climatic and topographic structuring homogenized lake and stream communities within ecoregions, as indicated by the strong overlap between the two community types and the weak correlation between biota and limnological variables. Notably, a significant increase in diatom species richness was related to increased water connectivity, interpreted to indicate that a decrease in the remoteness of the system increase species number. 4.Synthesis. We emphasize the strength of macroecological gradients (landscape configuration and climatic factors) in affecting both diatom diversity and community composition in the South American tropics. In this context, our results and the commonalities of ecoregion patterning with groups of macroorganisms (vegetation), suggest the need to integrate microbial ecology into a macroecology framework to unravel mechanisms behind diversity gradients.
Data from: Lake regionalization and diatom metacommunity structuring in tropical South America

X. Benito, S.C. Fritz, M. Steinitz-Kannan, and 2 more authors

Jul 2018

Abs DOI

Lakes and their topological distribution across Earth’s surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8ºN–30ºS and 58–79ºW) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables that inherently assessed the relative role of dispersal. Using complementary multivariate statistical techniques (Principal Component Analysis, cluster analysis, non-metric multidimensional scaling, Procrustes, variance partitioning), we examined diatom-environment relationships among different lake habitats (sediment surface, periphyton and plankton) and partitioned community variation to evaluate the influence of niche- and dispersal-based assembly processes in diatom metacommunity structure across lake clusters. The results showed a significant association between geographic clusters of lakes based on gradients of climate and landscape configuration and diatom assemblages. Six lake clusters distributed along a latitudinal gradient were identified as functional metacommunity units for diatom communities. Variance partitioning revealed that dispersal mechanisms were a major contributor to diatom metacommunity structure, but in a highly context-dependent fashion across lake clusters. In the Andean Altiplano and adjacent lowlands of Bolivia, diatom metacommunities are niche assembled but constrained by either dispersal limitation or mass effects, resulting from area, environmental heterogeneity, and ecological guild relationships. Topographic heterogeneity played an important role in structuring planktic diatom metacommunities. We emphasize the value of a guild-based metacommunity model linked to dispersal for elucidating mechanisms underlying latitudinal gradients in distribution. Our findings reveal the importance of shifts in ecological drivers across climatic and physiographically distinct lake clusters, providing a basis for comparison of broad-scale community gradients in lake-rich regions elsewhere. This may help guide future research to explore evolutionary constraints on the rich Neotropical benthic diatom species pool.
Lake regionalization and diatom metacommunity structuring in tropical South America

X. Benito, S.C. Fritz, M. Steinitz‐Kannan, and 2 more authors

Ecology and Evolution, Aug 2018

Abs DOI

Lakes and their topological distribution across Earth’s surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8°N–30°S and 58–79°W) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables that inherently assessed the relative role of dispersal. Using complementary multivariate statistical techniques (principal component analysis, cluster analysis, nonmetric multidimensional scaling, Procrustes, variance partitioning), we examined diatom–environment relationships among different lake habitats (sediment surface, periphyton, and plankton) and partitioned community variation to evaluate the influence of niche- and dispersal-based assembly processes in diatom metacommunity structure across lake clusters. The results showed a significant association between geographic clusters of lakes based on gradients of climate and landscape configuration and diatom assemblages. Six lake clusters distributed along a latitudinal gradient were identified as functional metacommunity units for diatom communities. Variance partitioning revealed that dispersal mechanisms were a major contributor to diatom metacommunity structure, but in a highly context-dependent fashion across lake clusters. In the Andean Altiplano and adjacent lowlands of Bolivia, diatom metacommunities are niche assembled but constrained by either dispersal limitation or mass effects, resulting from area, environmental heterogeneity, and ecological guild relationships. Topographic heterogeneity played an important role in structuring planktic diatom metacommunities. We emphasize the value of a guild-based metacommunity model linked to dispersal for elucidating mechanisms underlying latitudinal gradients in distribution. Our findings reveal the importance of shifts in ecological drivers across climatic and physiographically distinct lake clusters, providing a basis for comparison of broad-scale community gradients in lake-rich regions elsewhere. This may help guide future research to explore evolutionary constraints on the rich Neotropical benthic diatom species pool.
Open-data practices and challenges among early-career paleo-researchers

A. Koch, K.C. Glover, B. Zambri, and 3 more authors

Past Global Changes Magazine, Aug 2018

2017

A combined morphological and molecular approach to Nitzschia varelae sp. nov., with discussion of symmetry in Bacillariaceae

Rafael Carballeira, Rosa Trobajo, Manel Leira, and 3 more authors

European Journal of Phycology, Aug 2017

DOI

2016

Holocene palaeoenvironmental evolution of the Ebro Delta (Western Mediterranean Sea): Evidence for an early construction based on the benthic foraminiferal record

A. Cearreta, X. Benito, C. Ibáñez, and 2 more authors

Holocene, Aug 2016

Abs DOI

© 2016, © The Author(s) 2016.Major Mediterranean deltas began to develop during a period between 8000 and 6000 yr BP when the rate of fluvial sediment input overtook the declining rate of sea-level rise. However, different authors have argued that the Ebro Delta primarily formed during the late Middle Ages as a consequence of increased anthropogenic pressure on its river basin and these arguments are supported by the scarcity of previous geological studies and available radiocarbon dates. To reconstruct the environmental evolution of the Ebro Delta during the Holocene, we used micropalaeontological analysis of continuous boreholes drilled in two different locations (Carlet and Sant Jaume) on the central delta plain. Different lithofacies distributions and associated environments of deposition were defined based on diagnostic foraminiferal assemblages and the application of a palaeowater-depth transfer function. The more landward Carlet sequence shows an older and more proximal progradational delta with a sedimentary record composed of inner bay, lagoonal and beach materials deposited between 7600 and }textgreater2000 yr BP under rising sea-level and highstand conditions. This phase was followed by a series of delta plain environments reflected in part by the Carlet deposits that formed before 2000 yr BP. The Sant Jaume borehole is located closer to the present coastline and contains a much younger sequence that accumulated in the last 2.0 ka during the development of three different deltaic lobes under highstand sea-level conditions. The results of this study reinforce the idea that the Ebro Delta dates to the early Holocene, similar to other large Mediterranean deltas.
Benthic foraminifera as indicators of habitat in a Mediterranean delta: implications for ecological and palaeoenvironmental studies

Xavier Benito, Rosa Trobajo, Alejandro Cearreta, and 1 more author

Estuarine, Coastal and Shelf Science, Aug 2016

DOI

2015

Benthic diatoms in a Mediterranean delta: ecological indicators and a conductivity transfer function for paleoenvironmental studies

Xavier Benito, Rosa Trobajo, and Carles Ibáñez

Journal of Paleolimnology, Aug 2015

DOI
Benthic foraminifera as indicators of habitat change in anthropogenically impacted coastal wetlands of the Ebro Delta (NE Iberian Peninsula)

Xavier Benito, Rosa Trobajo, Carles Ibáñez, and 2 more authors

Marine Pollution Bulletin, Aug 2015

DOI

2014

Modelling Habitat Distribution of Mediterranean Coastal Wetlands: The Ebro Delta as Case Study

Xavier Benito, Rosa Trobajo, and Carles Ibanez

Wetlands, Aug 2014