Raquel Ortells

• PhD
• Assistant Professor at University of Valencia

Wind is expected to be one of the main vectors of passive dispersal for small zooplankters between discrete, unconnected habitats. However, little is known about the differences in the dispersal capacity of species in relation to their propagule traits. Here we assessed the effect of volume and weight of diapausing eggs and substrate granulometry o...

Freshwater zooplankter Brachionus plicatilis is able to inhabit different habitats and locally adapt to their environmental conditions. It also shows a high degree of population structuring in small geographical regions. Here we try to shed light on the evolution of reproductive isolation in populations of B. plicatilis with presumptive gene flow a...

In a world where it seems best to go unnoticed, many creatures display their beauty in plain sight. We could even say that we are surrounded by beauty. A diverse and overwhelming beauty that inspires artists and engineers, one that scientists have tried (and keep trying) to study and understand. In this Metode SSJ monograph we will see how science...

The emergence of reproductive isolation is key in maintaining within- and between-species diversity and one of the initial steps of speciation. In the Iberian Peninsula, the diverging populations of the Brachionus plicatilis rotifer create an ideal system to shed light on the mechanisms that give rise to the emergence of reproductive isolation. Her...

The development of reproductive barriers promotes within-species divergence and is a requisite for speciation to occur. Mate recognition in the rotifer B. plicatilis is mediated through a surface glycoprotein called Mating Recognition Protein (MRP). Here we investigate the genetic variation of the mmr-b, MRP coding, gene in different natural popula...

Zooplankton community assembly after flooding in temporary ponds depends mostly on abundance and diversity of the dormant propagule bank. However, our understanding of the hatching patterns of zooplankton is imperfect. We performed an ex situ experiment to study the species composition and temporal sequence of zooplankton emergence from sediments i...

Studying evolution in the face of environmental uncertainty is crucial to understand biological diversity, because diversifying life strategies is key to survival and reproduction in uncertain environments. Rotifers are planktonic microinvertebrates that live in inland water bodies. Their complex life cycle combines sexual and asexual reproduction...

Restoration is an ecological tool that aims to recover the prior conditions and functioning of a degraded habitat. Three restoration projects targeted a dune slack system in the Eastern Iberian Peninsula and created a mosaic of ponds restored over three different periods: 1998, 2003 and 2007, the latter coinciding with the start of our study. Resto...

Cyclically parthenogenetic rotifers are facultative sexual aquatic microinvertebrates that live in continental and coastal waters and attracted the scientific interest of Professor M. R. Miracle. Some of her early studies anticipated the use of these rotifers as model organisms to test hypotheses in population and evolutionary ecology. This short r...

In the area of La Devesa there are over 40 water bodies (Rueda-Sevilla et al. 2006; Rueda 2015). The main malladas, following the traditional toponymy and from north to south, are: mallada del Quarter, del Saler, de La Rambla, Redona, del Garrofer, Llarga, de la Mata del Fang, de l’Hospitalet, de la Torre, Malladeta, and del Canyar. There is also a...

Spatial distribution of Branchinectella media (Crustacea, Branchiopoda) in a saline pond from "La Mancha Húmeda": a case of habitat selection? Branchinectella media is a commonly observed anostracan in Mediterranean temporary saline ponds. Despite its wide distribution, many aspects of its natural history are unknown or poorly studied. In this work...

The production of diapausing eggs is an ecological strategy commonly used by zooplanktonic organisms to cope with adverse conditions in time-varying habitats. Traits related to diapause (e.g., the time spent in diapause, the hatching fraction of diapausing eggs, or the amount of reserves allocated to them) should be combined by natural selection to...

At some stage in their life cycle, most zooplankton in temporary waters produce dormant eggs that assemble in a persistent egg bank to cope with unfavourable conditions. As part of a risk-spreading strategy, only a fraction of the egg bank hatches during a single inundation. Besides this dispersal in time, resistant dormant eggs also disperse in sp...

Understanding the factors associated with the life cycle of organisms living in temporary wetlands as well as the mechanisms driving their spatio-temporal distribution are great challenges in population ecology. The anostracan Branchinectella media has a wide geographic distribution, however, little is known about its population dynamics. The aim o...

The toxicity of Bacillus thuringiensis var. israelensis on zooplanktonic microcrustaceans was evaluated using individuals collected in coastal wetlands where this larvicide has been used for mosquito control over the last decades. We tested five zooplankton species that coexist with mosquito larvae: two copepods (both nauplii and adults of Tropocyc...

Nutrients and carbon were studied in the temporary and permanent dune ponds of one of the few restored Mediterranean dune systems. The results indicate that small, low nutrient dune ponds can have a relevant role for carbon storage and processing, especially in the limestone areas. Despite the low percentage of organic matter in the sediment and wa...

Restored ponds are uniquely suitable for the study of successional processes on aquatic communities. In a set of dune slacks of different restoration ages, we monitored monthly the environmental and community shifts of one newly restored pond over 4 years and compared it with older ponds. Questions were (i) how does the community change with time i...

Zooplankton assemblages in neighboring ponds can show important spatial and temporal heterogeneity. Disentangling the influence of regional versus local factors, and of deterministic versus stochastic processes has been recently highlighted in the context of the metacommunity theory. In this study, we determined patterns of temporal and spatial var...

Malladas de El Saler is a mosaic of dune slacks scattered along a coastal sand bar in the Mediterranean region. Active populations of the fairy shrimp T. stagnalis are exclusively present in one of these ponds. We combined field observations and laboratory experiments to find the ecological requirements of T. stagnalis that determine this habitat e...

During the initial stages of population build‐up in new habitats, the time at which immigrants arrive may influence their contribution to the population and thus determine population genetic structure. While the numerical advantage associated with founder effects may promote dominance of the offspring of early colonizers, fitness differences associ...

We have tracked changes in the zooplankton assemblages of three temporary duneslacks (locally known as “malladas”) in Albufera Natural Park, during four consecutive years (from 2007 until 2011). These ponds were restored in different periods; 1998 (Old), 2003 (Intermediate) and 2007 (Recent). They were monthly sampled during the flooded periods (us...

In habitats recently colonized by cyclical parthenogens, founder events lead to genetic differences between populations that do not erode quickly despite ongoing dispersal. By comparing the genetic composition during initial colonization with that of the diapausing egg bank at a local scale, we here present the relative contribution of the founding...

In temporary ponds, reestablishment of zooplankton communities depends on recruitment from the egg bank, the arrival of dispersers from within the region, and on successful establishment of newly arrived species following interaction with local abiotic and biotic factors. When the ponds dry up, zooplankton species may survive as dormant eggs, and s...

New habitats are an interesting tool to monitor colonization processes in the light of changes in genetic structure and evolutionary potential of populations. Cladocerans are cyclical parthenogens that offer the possibility to track genetic changes during the colonization process due to the alternation of sexual and asexual phases. The locally call...

En el Parque Natural de l’Albufera (Valencia), la mayoría de las charcas situadas en la barra arenosa que separa el lago de la Albufera del mar Mediterráneo fueron aterradas en los años 60 para proceder a la urbanización de la zona. Este proceso se paralizó en los 70, y desde finales de los 80 hasta la actualidad se han llevado a cabo proyectos de...

A microsatellite-enriched genomic library was developed for the water flea Daphnia atkinsoni Baird, 1859, a dominant species of intermittent wetlands in Europe. Eight polymorphic microsatellite markers were successfully optimized. Characterization of 77 individuals from Belgium and Spain showed moderate (in the former) to high (in the latter) level...

Colonization dynamics may strongly influence within and among population genetic variation and evolutionary potential of populations. We here analyze the genetic structure during the first three years of 12 cyclical parthenogenetic Daphnia populations in newly created pond habitats. One to three genotypes were observed to colonize the populations,...

In a homogeneous aquatic environment, clonal diversity in cyclical parthenogens should decrease with time while the population is active in the water column due to directional clonal selection. On the contrary, if planktonic populations experience a heterogeneous environment the loss of clonal diversity with time could be neutralised. We tested the...

The genetic structure of cyclic parthenogenetic zooplankton populations is strongly determined by the consequences of combining sexual and asexual reproduction in the same life cycle. Since the pioneering population genetic studies on freshwater zooplankton in the 1970's, a distinction has been made between the genetic structure of permanent and in...

The hatching of diapausing eggs is a means of temporal dispersal that can provide populations with genotypes adapted to different environments. In a salinity-variable shallow lake, we predicted that the mixing of different age-classes of eggs in the sediment may yield genotypes with different salinity optima. The alternative would be the absence of...

1. The coexistence of five cryptic species of the rotifer species complex Brachionus plicatilis was investigated in four coastal Mediterranean ponds. Monthly sampling was undertaken for 15 months and species were characterised using allozyme electrophoresis. 2. We describe species-diagnostic allozyme loci that can be used for rapid identification o...

1. Only a few studies have compared patterns of genetic variation among populations of different Daphnia species on a regional scale. The present study addresses this gap and examines the relationship between diversity as revealed by allozyme variation and habitat size for populations of Daphnia pulex, D. obtusa and D. curvirostris in Flanders (Bel...

Here we present the first population study on the genetic diversity of a rotifer species complex (Brachionus plicatilis) in a geographic area (Eastern Spain), which includes inland and coastal habitats. A novel approach was used by hatching resting eggs from sediment samples rather than sampling rotifers from the water column. Hatchlings from resti...