Alain Maasri

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global...

Opportunities to understand and protect natural aquatic diversity in both relatively pristine and managed rivers can be enhanced with a comprehensive, system-wide understanding of a river’s hydrogeomorpholgy and its effects on ecological structure and functioning from the river’s headwaters to its terminus in an ocean, lake, or natural endorheic ba...

The decline of wet-grassland breeding bird populations across Europe, and Germany more specifically, continues unabated. In an effort to address this ongoing issue, we conducted a Horizon Scanning survey to identify the current strengths, weaknesses, future opportunities, and threats for wet-grassland breeding bird conservation across both continen...

Identification and Ecology of Freshwater Arthropods in the Mediterranean Basin covers the entire Mediterranean basin, including parts of Europe, Asia, Africa and the Mediterranean islands, but excluding other biogeographic locations with Mediterranean climates located outside the region. The book provides an extensive description of the taxonomy an...

In this chapter, we provide an overview of the characteristics of the Mediterranean climate, the human imprint and anthropogenic disturbances around the Mediterranean basin that shaped its ecosystems for millennia, and a description of Mediterranean streams, rivers, lakes, and wetlands. We also discuss the role of natural and anthropogenic disturba...

Fish assemblages, defined by taxonomy or functional traits, –respond to regional and local habitat variation. Our hypothesis was that fish assemblages could be best predicted using reach‐scale (RS) hydrology variables over valley‐scale (VS) hydrogeomorphology variables for US and Mongolian rivers. We further predicted that fish traits were predicte...

Motivation Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macr...

Quantifying the trophic basis of production for freshwater metazoa at broad spatial scales is key to understanding ecosystem function and has been a research priority for decades. However, previous lotic food web studies have been limited by geographic coverage or methodological constraints. We used compound‐specific stable carbon isotope analysis...

Background: Critical thinking (CT) is recognised as an essential component of higher education, and many academic institutions are working on improving their students’ CT skills. To date, the complex relationships between students’ ability to think critically and their age, sex, academic performance, major and prior experience taken all together ha...

The cover image is based on the Viewpoint A global agenda for advancing freshwater biodiversity research by Alain Maasri et al., https://doi.org/10.1111/ele.13931. Image Credit: Solvin Zankl. image

Stream fishes are restricted to specific environments with appropriate habitats for feeding and reproduction. Interactions between streams and surrounding landscapes influence the availability and type of fish habitat, nutrient concentrations, suspended solids, and substrate composition. Valley width and gradient are geomorphological variables that...

We cover basic concepts and advances in stream ecology related to the River Continuum Concept (RCC). The RCC describes how position in the watershed influences rivers and streams. These influences include materials washing in from the watershed above and those properties dictated by terrestrial habitats that border the rivers or streams in the vici...

Current understanding of how streamflow in terminal basins is driven by climatic and hydrogeomorphic characteristics is limited, despite the fact that these closed systems show an increased sensitivity to climate change in terms of streamflow and an increase in demand for water resources. We examined streamflow patterns in 2 major terminal basins,...

River metabolism modeled from diurnal dissolved oxygen (DO) has become a widely used metric of ecosystem function, yet many papers provide insufficient methodological detail for replication. Only 79% of 43 sampled papers published from 2015 to 2019 mention calibration, 44% describe sensor placement, and 34% did not describe estimation approaches su...

We examined how communities of macroinvertebrates occurring in functional process zones (FPZs) are affected by the location of FPZs in the river continuum. We delineated FPZs for three rivers displaying significant disparities in elevation, annual precipitation, valley shape, and other valley-scale hydrogeomorphic variables. We extracted correspond...

River hydrogeomorphology is a major driver shaping biodiversity and community composition. Here, we examine how hydrogeomorphic heterogeneity expressed by Functional Process Zones (FPZs) in river networks is associated with fish assemblage variation. We examined this association in two distinct ecoregions in Mongolia expected to display different g...

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pres...

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pres...

The invasion of freshwater ecosystems by non‐native species can constitute a significant threat to native species and ecosystem health. Non‐native trouts have long been stocked in areas where native trouts occur and have negatively impacted native trouts through predation, competition, and hybridization. This study encompassed two seasons of sampli...

A recent global meta‐analysis reported a decrease in terrestrial but increase in freshwater insect abundance and biomass (van Klink et al., Science 368, p. 417). The authors suggested that water quality has been improving, thereby challenging recent reports documenting drastic global declines in freshwater biodiversity. We raise two major concerns...

We analyze here the nature of research in freshwater macrosystem biology (especially lotic studies) from both conceptual and current research perspectives. The boundaries of permanent and transitional lotic macrosystems from the smallest to largest spatial extents are described. We contrast ecosystem vs. macrosystem research and macroecology vs. ma...

Macrosystems are integrated human–natural systems, in recognition of the fact that virtually every natural system on Earth influences and is influenced by human activities, even over long distances. It is therefore crucial to incorporate inherent properties of broad‐scale systems, such as human–nature connectivity and feedbacks at multi‐scales, int...

The metacommunity concept has received increasing interest in the past two decades. However, there has been limited research examining metacommunity structure of communities in high mountain streams. These ecosystems are often physically constrained and can display large environmental gradients within a relatively small spatial extent. Here, we exa...

The dissolved oxygen diel cycle is an inherent feature of stream ecosystems, and the amplitude in this diel fluctuation is thought to strongly influence the composition of stream communities. For instance, extremely low dissolved oxygen saturation (DDO) values have well-documented effects on stream macroinvertebrates. Less is known, however, about...

Picture of Khovd River in Western Mongolia, taken in 2010 during my postdoc at the Academy of Natural Sciences of Philadelphia.

We assessed the potential influence of hydrological connectivity among subdrainages on the structural and functional organization of stream macroinvertebrate metacommunities in 2 adjacent, large Asian watersheds (~1.4 million km2). To examine the structural organization of metacommunities, we used multisite β-diversity partitioning and applied the...

Abstract – Patterns of metacommunities are the product of heterogeneous combinations of local and regional influences driven by asymmetric dispersal, uneven energy flow, and disparities in habitat availability. Thus, from a macroecological research standpoint, the focus is on the structural and dynamical properties that dictate metacommunity struct...

Streams in the Mongolian Altai Mountains are mostly fed from glaciers and are extreme conditions for may-flies because of high elevation, low temperatures and low annual precipitation. Previous information about mayflies of Western Mongolia is scarce, but with this study a total of 38 species belonging to 26 genera and subgenera and 8 families of m...

Environmental flow is a key component of an Integrated Water Resources Management and accounts for the volume of water allocated for ecosystem functioning. As in return ecosystems provide services to people, an environmental flow is not exclusively a matter of sustaining a healthy ecosystem but also a matter of supporting riparian livelihoods. Sin...

The Lower Jordan River stretching between the Sea of Galilee and the Dead Sea constitutes the main transboundary freshwater resource shared between Jordan, Israel, and Palestine. Over extraction and pollution were identified as the main disturbances affecting the river leaving it in a critical condition. Thus, an effective partnership of the three...

Background Mongolia’s riverine landscape is divided into three watersheds, differing in extent of permafrost, amount of precipitation and in hydrological connectivity between sub-drainages. In order to assess the vulnerability of macroinvertebrate communities to ongoing climate change, we consider the taxonomic and functional structures of stream c...

Mongolia, a landlocked country of the Central Asian plateau, is experiencing a significant modification of herding practices coupled with an increase in livestock numbers. These modifications lead to increasing impacts of grazing on the Mongolian steppes with major consequences on the waterbodies. We researched the impacts of grazing intensity on t...

Human-caused climate change as a leading threat for biodiversity conservation of the aquatic biota has been the emergent discussion of the last two decades. Climate change scenarios forecast a global increase of temperatures, annual rainfall, atmospheric moisture and the shrinkage of permafrost. The plasticity and adaptation capacities of the strea...

Chaoborus larvae are voracious predators of zooplankton able to change their specific composition and size structure. Thus they appear as competitors of fish. They also represent food for planktophage fish. The temporal dynamics of Chaoborus larvae was studied (from january to october 1997) in the fishery of Bakro (5°33’N and 3°15’W) situated in la...

Water enrichment has been described to have major impact on the freshwater food-webs structure. We investigated the structure of the epilithic algal assemblage and the gut contents of a rheophilic orthoclad in situ in a nutrient enriched stream. 4-th instar larvae of Eukiefferiella claripennis, a widespread orthoclad in the Palearctic ecozone and a...

The Bolmon lagoon (south-eastern France) is located in the coastal hinterland of the Mediterranean Sea. It is connected to the salty Berre pond and in the other hand receives fresh waters from the La Cadiere River. This hyper-shallow lagoon has been classified in the early 70's as β mixo-mesohaline. Bolmon lagoon is important for human activities (...

The taxonomic richness erosion and the role of tributaries in the maintenance of the taxonomic richness were considered in a Mediterranean catchment in southeastern France. Nine stations were chosen along the Arc stream (three stations downstream from an organic effluent and one station upstream from the pollution source) and on two groups of tribu...

The effects of nutrient enrichment of stream water on epilithic chironomid larval assemblages were examined during spring in a Mediterranean catchment. Three reaches that differed in degree of enrichment were selected for comparison. Water chemistry, epilithon biomass (as ash-free dry mass [AFDM]), epilithic algal biomass (as chlorophyll a [chl a])...

The chironomid fauna was examined in a Mediterranean stream under different degrees of water enrichment. Epilithic chironomid larvae and algae were sampled during the spring season in order to elucidate the effect of the algae taxonomic composition on the chironomid community structure. It is suggested that epilithic algae may be an important facto...

The chironomid species inhabiting a natural dead arm (the Pilet dead Arm), two artificial backwaters (the Saxy Dyke field and the Ranchier Dyke Field) and the main channel of the lower Rhône River (South of France) were studied. A between-class (between-station) Correspondence Analysis (CA) showed that, on the scale of the alluvial plain, habitat i...