Estación Biológica de Doñana - CSIC

Un proyecto con participación del CSIC une a 33 países para secuenciar el genoma de las especies europeas

77176912K — Mon, 16 Sep 2024 07:56:56 +0000

16 September 2024

Project with the participation of the CSIC brings together 33 countries to sequence the genome of European species

Researchers from the Institute of Evolutionary Biology (IBE, CSIC-UPF), the Spanish National Science Museum (MNCN-CSIC), the Doñana Biological Station (EBD-CSIC) and the Botanical Institute of Barcelona (IBB-CSIC) participate in this project

The initiative pave the way for a new inclusive equitable model for biodiversity genomics

A new project led by the European Reference Genome Atlas, the European node of the global Earth BioGenome Project (EBP) has brought together a group of researchers and institutions across 33 countries to produce high-quality reference genomes of 98 European species. Institutes of the National Spanish Research Council (CSIC) have played a key role as the genomic node of this pilot project, participating in setting the highest standards for genome sequencing in the species studied, both vertebrates and invertebrates. Researchers from the Institute of Evolutionary Biology (IBE, CSIC-UPF), the Spanish National Science Museum (MNCN-CSIC), the Doñana Biological Station (EBD-CSIC) and the Botanical Institute of Barcelona (IBB-CSIC), as well as the Spanish National Centre for Genomic Analysis (CNAG) and the Barcelona Computing Center (BSC) among others, have taken part in this project.

The initiative aims at creating a high-quality reference genome database for all the animals, plants, and fungi. Among many of the project's milestones are the first chromosome-level genome assemblies of species from Greece, one of Europe’s most biodiverse countries. Species such as the Cretan wall lizard and Aristotle’s catfish were sampled by local researchers in Greece to produce genomes that are now openly available for anyone across the world to access and study.

“The Pilot Project has highlighted key challenges, positioning ERGA as a model for decentralised, inclusive, and equitable biodiversity genomics initiatives around the world”, as reported in a new collection of research articles published today in the journal NPJ Biodiversity.

One of the biggest challenges facing the consortium was to establish a quality standard for DNA extraction and processing for all species in the project that would allow the highest quality sequencing and data analysis and that could be shared within the scientific community. Rosa Fernández, principal investigator at IBE, and currently a member of the ERGA executive committee, has been involved in setting this standard, raising the quality of the genomes to chromosome-level precision.

So far, many genomics efforts have employed techniques such as Illumina, PacBio or Nanopore, which are capable of analysing short or long DNA sequences that must then be assembled to reconstruct the genome of the species under study. But this is not enough to have a genome of the highest quality. The IBE team has taken a step forward by employing the novel Hi-C technique, which allows the sequencing of complete chromosomes and the reconstruction of the three-dimensional structure of the genome, optimising protocols for non-model species that are complicated to process in the laboratory.

‘The genome is packed like a ball inside the cell nucleus. With this new technique we are able to unravel and read the ball chromosome by chromosome. In addition, we preserve the folding information, which is key to deciphering how the genome is assembled and, above all, to being able to reconstruct its three-dimensional structure,’ explains Fernández.

Fernández's team at IBE, led by Judit Salces-Ortiz and Nuria Escudero as key players in the optimisation of the protocols, participated in the sequencing of more than 14 genomes in the pilot project, accompanying several European groups in the fine-tuning of the technique, both in vertebrate and invertebrate species.

The project emphasises equity and inclusiveness, with the aim of making research and genomic resources accessible regardless of geographical boundaries. For many of the participating countries and researchers, the project has been the first opportunity to actively participate in the generation of state-of-the-art reference genomic resources to analyse local native biodiversity.

‘The programme has allowed us to establish a network of infrastructures and collaborations between research groups to generate high quality genomes that is allowing us to more easily tackle the sequencing of new genomes,’ emphasises Maria José Ruiz, CSIC researcher at the EBD. This scientist is a member of the ERGA data analysis committee, which aims to improve the development of genomics applications, establish standard data analysis protocols for different taxonomic groups and promote collaboration and knowledge sharing in genomic data analysis.

European effort with global impact

The ERGA pilot project has also succeeded in generating visibility for the growing importance of biodiversity genomics in Europe and beyond. Genomic data has immense potential to inform conservation actions for endangered species and generate discoveries in the fields of evolution, human health, bioeconomics, biosecurity and many other applications.

Among the species sequenced by the project is, for example, the Argentine grouper, a commercially important fish species of the North Atlantic. This new reference genome will allow scientists to make more accurate assessments of the genetic status of the species' stocks, which will ultimately guide management decisions to ensure that fishing practices are sustainable and responsible.

‘As the global scientific community strives to harness the full potential of genomic data, the creation of a Europe-wide collaborative network within ERGA project accelerates scientific progress and facilitates its translation into tangible benefits for biodiversity,’ says MNCN researcher Ana Riesgo, who coordinates the project in Spain with Brent Emerson and Rosa Fernández. ‘In addition, the network helps researchers at all stages of their career to find and share training, collaboration and funding opportunities,’ she continues.

‘This project is also important because access is equitable. One of the objectives was to generate a Europe-wide network that was as inclusive as possible and involved countries where resources for genomic studies are usually limited. And this has been achieved, making access affordable for everyone,’ concludes Ruiz.

ERGA, part of the BioGenome of the Earth project (EBP)

ERGA is the European node of the Earth BioGenome Project (EBP). To achieve its goal of sequencing all eukaryotic life on Earth, the EBP needs global participation and new decentralised models of genome production.

The ERGA pilot project has demonstrated that a fully distributed, collaborative and coordinated genome production model is not only feasible, but also effective, even on a continental scale and without a central source of funding available. In fact, most of the project's budget came from the efforts of individual members and partner institutions, with additional support from sequencing partners and commercial sequencing companies that provided various contributions.

The initiative has also helped to identify and address the many challenges involved in working on an international scale. These challenges include the legal and logistical hurdles of shipping biological samples across borders, resource disparities between countries, and balancing decentralisation with the need for standardisation to ensure that the project produces reference genomes of the highest possible quality.

Cartney A M Mc, Formenti G, Mouton A, (...) Fernandez R, (...) Mazzoni C J, et. al. The European Reference Genome Atlas: piloting a decentralised approach to equitable biodiversity genomics; npj Biodiversity. DOI: 10.1038/s44185-024-00054-6

Un estudio analiza la distribución de los mosquitos transmisores de la malaria en España

outreach@ebd.csic.es — Mon, 09 Sep 2024 12:41:47 +0000

06 May 2024

New study analyses the distribution of malaria-transmitting mosquitoes

Although the disease was eradicated in Spain six decades ago, about 800 new imported cases are detected every year

Malaria is endemic in Africa, Central and South America and a large part of Asia. / EBD-CSIC

A recent study coordinated by researchers of the Doñana Biological Station – CSIC and the Spanish National Centre for Epidemiology (ISCIII-CNE) and the CIBER of Epidemiology and Public Health (CIBERESP) have analyzed the distribution of the main malaria vector mosquito in Spain. In this study, where researchers from different universities, research centres, pest control companies and mosquito control services, has shown that the mosquito Anopheles maculipennis is widely distributed in Spain, with special predilection for river mouths and valleys with irrigated farming areas.

Malaria is a serious disease present in many tropical countries, caused by infection by protozoa of genus Plasmodium transmitted by mosquitoes of the genus Anopheles. However, in the past, transmission of this disease was also common in other parts of the world, including most of Europe and other economically developed countries. Eradication campaigns in the mid-20th century succeeded in eradicating it in many countries, with Spain officially becoming malaria-free in 1964. Since then, very sporadic cases of local transmission have been recorded due to the arrival of infected travelers and the presence in the territory of mosquitoes capable of transmitting the parasite. In Spain, only two cases of local transmission due to mosquito bites have been reported during the 21st century.

The researchers have analyzed the mosquitoes present in more than 3,000 localities in the Iberian peninsula and the Balearic Islands. Every year between 700 and 850 cases of imported malaria are detected in Spain, i.e. in patients who have been infected in an endemic area, mainly in Africa. Only 15% of these cases are related to malaria species that could be effectively transmitted by the Anopheles maculipennis mosquito.

"Although the risk of local transmission is very low, these models are useful to identify areas with a higher risk of local transmission. It is necessary to follow prophylactic measures when traveling to malaria-endemic countries," says Jordi Figuerola, researcher at the Doñana Biological Station (EBBD-CSIC) and principal investigator of CIBERESP. Since mosquitoes are transmitters of diseases to humans, Understanding the climatic and ecological factors that impact their abundance and distribution is crucial.

"Travelers must be aware of the risks present in the areas they plan to visit and know how to act when coming back. In addition, healthcare professionals should know how to recognize and respond to cases of imported diseases such as malaria, including reporting them to the Public Health System for surveillance and to be able to carry out the appropriate actions", conclude Diana Gómez Barroso and Beatriz Fernández, researchers at the Spanish National Epidemiology Center and CIBERESP.

Referencia

Taheri S, González MA, Ruiz-López MJ, Magallanes S, Delacour-Estrella S, Lucientes J, Bueno-Marí R, Martínez de la Puente JM, Bravo-Barriga D, Frontera E, Polina A, Martinez-Barciela Y, Pereira JM, Garrido J, Aranda C, Marzal A, Ruiz-Arrondo I, Oteo JA, Ferraguti M, Gutiérrez-López R, Estrada R, Miranda MÁ, Barceló C, Morchón R, Montalvo T, Gangoso L, Goiri F, García-Pérez AL, Ruiz S, Fernandez-Martinez B, Gómez-Barroso D, Figuerola J. Modeling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases. Emerg Microbes Infect. 2024. DOI: https://doi.org/10.1080/22221751.2024.2343911

Recrean el accidente de Chernóbil en el laboratorio para estudiar los efectos de la radiación en la biodiversidad

outreach@ebd.csic.es — Mon, 02 Sep 2024 12:33:33 +0000

10 May 2024

Recreating the Chernobyl accident in the lab to study the effects of radiation on biodiversity

The aims include to assess if melanin is a protective factor against radiation and if there are patterns of adaption to radioactivity

The researcher Pablo Burraco, in one of the climatic chambers of the Doñana Biological where he is conducting one of the experiments. Photo: Banco de Imágenes EBD-CSIC

On April 26, 1986, reactor 4 of the Chernobyl nuclear power plant accidentally exploded causing the largest release of reactive material in history. 38 years later, the Chernobyl area has become an excellent natural laboratory to study how radiation affects fauna and flora and to investigate how species recolonize territories abandoned by humans. A scientific team from the University of Oviedo and the Doñana Biological Station - CSIC has been working in this area for eight years. Today, while the war makes it impossible for them to return to Chernobyl to continue their research, the scientists have launched a series of experiments to recreate the accident and study how radiation affects amphibians and beetles.

"Amphibians are a good study model for this type of research. They are exposed to both aquatic and terrestrial environments and move little, so their exposure to radiation is usually more stable," says Pablo Burraco, a researcher at the Doñana Biological Station - CSIC. The scientist is directing, together with researcher Iván Gómez-Mestre, the first of the experiments in the laboratories of his research center, located on Isla de la Cartuja in Seville. The aim is to simulate a nuclear accident to test whether melanin is a protective factor against radiation, something already suggested by the observational studies they were carrying out in Chernobyl, before the pandemic put the brakes on their projects.

In 2016, researcher Germán Orizaola of the University of Oviedo initiated a study to investigate the effect of radioactivity on the oriental tree frog (Hyla orientalis). The following year he was joined by researcher Pablo Burraco. After three years of exhaustive sampling at Chernobyl, the results seemed to indicate that radiation had little apparent effect on the frogs, except for one thing: their coloration. Those living in the Exclusion Zone, the area that was evacuated after the disaster, had a darker skin than those living outside it. Some even had a completely black coloration, as opposed to the bright green that this species usually has.

"The results suggested that melanin had protected them from ionizing radiation, which is released in a nuclear accident, in a similar way that it protects us from ultraviolet radiation," explains Germán Orizaola. Natural selection must have acted implacably after the nuclear explosion, causing darker frogs to survive in greater proportion than those with greener colorations.

Coloration gradient of the study frog in northern Ukraine. Photo: Germán Orizaola and Pablo Burraco.

Recreating a nuclear accident

The study was merely observational. They had found a correlation that suggested that melanin was a protective factor, but it did not prove it. To do so, they decided to reproduce the nuclear accident under controlled conditions, something they could do in laboratories far from Chernobyl under strict compliance with European regulations.

The researcher Pablo Burraco first place the larvae of the same clutch of Iberian spadefoot toad (Pelobates cultripes), which is very abundant in Doñana, in black and white buckets. It is known that, like many other amphibians and reptiles, the larvae of this species have a great plastic capacity and are able to change the color of their skin depending on the environment. Thus, he would make some toads darker and others lighter. With the collaboration of the National Accelerator Center, the larvae were subjected to different levels of radiation for a short period of time.

"The doses were not lethal so, at first, we did not detect differences in mortality related to coloration," explains Pablo Burraco. The experiment has been ongoing for over a year now and during this time, the toads have been kept in climatic chambers under very controlled conditions to avoid the incidence of other factors. "At the moment they look very good and there are practically no differences in size, but something is starting to happen inside them. We are beginning to see differences in mortality," says the researcher. We will have to wait a few more months to obtain the definitive results.

Los investigadores Pablo Burraco y Germán Orizaola en Stirling (Escocia), donde han iniciado un experimento para investigar cómo afecta la radiación al desarrollo larvario de las ranas del género Xenopus // Foto: Germán Orizaola

The team has recently started another experiment with frogs of the genus Xenopus, following a similar approach. The experiment was conducted at the University of Stirling in Scotland with funding from the Spanish Nuclear Safety Council. In this case, radiation exposure is less intense but longer in duration, replicating the varied radiation levels found in present-day Chernobyl. "With this experiment we want to see what happens if frogs are exposed to radiation throughout embryonic development," explains Pablo Burraco. The researchers will study the effects of radioactivity on the frogs' survival, physiology and morphology.

During these weeks, the team is carrying out tests to start a third experiment with beetles that will also be carried out at the Doñana Biological Station, in collaboration with Francisco García's research group and with the National Accelerator Center. One problem in this type of research is that vertebrates typically have long reproductive cycles. Beetles, on the other hand, have a new generation every 20 days. "Working with beetles we can see if there are transgenerational effects and adaptation patterns to radiation exposure and thus see the evolution in real time," says the researcher.

Working with Przewalski's horse

Another of the projects that the scientific team planned to develop in Chernobyl was related to the study of the recolonization processes of the Przewalski's horse. At one point, there were only a dozen of this horse breed in captivity, but now, due to conservation efforts, hundreds roam freely in Europe and Asia. In 1998, a few individuals were introduced in Chernobyl and the population has grown to around 200 specimens.

As long as the safety conditions are not ideal to return to Chernobyl, the team has decided to start investigating with the population in Burgos (Spain) recently reintroduced as part of the Paleolítico Vivo project. The objective is to initiate genomic research and develop methodologies that can be used later at Chernobyl to study the renaturalization processes of Przewalski's horse and also the effect of radiation on them, which are more similar to humans than amphibians.

Chernobyl, 38 years later

"Chernobyl is not what appears in documentaries," says Germán Orizaola. "It has become a spectacular wildlife refuge." After the nuclear accident, an Exclusion Zone of 4,700 km2 was created around the Chernobyl power plant. Over several decades with minimal human presence, the area has turned into a oasis for biodiversity inhabited by wolves, bears, lynx, and wild horses like Przewalski's.

"We have national parks like Doñana or Picos de Europa in Spain that we should leave only for conservation. There is no need for excursions or roads," says Orizaola. The explosion of the Chernobyl nuclear power plant was one of the most dangerous accidents in the history of mankind. 38 years later, once radiation levels have dropped, the area has become a perfect natural laboratory to understand what happens when humans withdraw from a territory. Sometimes the best solution to conserve nature is simply, according to the researcher, not to disturb it.

On the horizon, the steel "sarcophagus" covering reactor 4 of the Chernobyl nuclear power plant // Photo: Germán Orizaola.

El urogallo cantábrico, en peligro crítico de extinción, necesita un rescate genético para tener una oportunidad

outreach@ebd.csic.es — Fri, 30 Aug 2024 13:01:07 +0000

14 May 2024

The critically endangered Cantabrian capercaillie needs a genetic rescue to have an opportunity

A scientific team from the Doñana Biological Station – CSIC shows that the Cantabrian population of capercaillie has clear symptoms of genetic depression due to inbreeding

The idea of the uniqueness of this population, currently without scientific support, has so far excluded the possibility of mixing it with birds from other populations.

Male of Cantabrian capercaillie. Photo: José Luís Rodríguez, proyecto LIFE+ Urogallo Cantábrico

The western capercaillie population in the Cantabrian Mountains has undergone an seemingly unstoppable decline for decades and it is currently Critically Endangered. Researchers from the Doñana Biological Station – CSIC has just published a study in the journal Evolutionary Applications indicating that the population may be involved in an extinction vortex related to endogamy and genetic depression. In similar situations, there are successful examples of genetic rescue, alleviating the negative effects of endogamy by introducing individuals from other populations. However, Cantabrian capercaillie has been considered a unique subspecies (Tetrao urogallus cantabricus), so the possibility of mixing with other populations has not been considered. Today it is known that this classification has not solid bases and the results of this study suggest that the pretended exclusivity of the Cantabrian capercaillie has been a trap for its conservation.

The capercaillie has a continuous distribution across the vast Eurasian taiga forests, as well as a set of relict, isolated populations in different European mountain ranges. Up to twelve of these populations were described as subspecies during the 20^th century. The last one, in the 1960s, was the Cantabrian capercaillie. The definition of those subspecies was never solid and today there is no scientific basis for the subspecies classification of capercaillie in general, and the Cantabrian subspecies in particular. The proliferation of capercaillie subspecies is an example of taxonomic inflation, i.e., the description of taxonomic units (in this case, subspecies) that would not deserve that status.

In general, the conservation status of the montane populations of capercaillie is very poor, and that is particularly true for the Cantabrian capercaillie. It is believed that the population would have occupied a territory of some 30,000 km2 before the 20th century. This area would have been reduced to 10,000 km2 in the early 1970s, and to barely 1000 km2 at present. Between 1978 and 2019 the number of capercaillie in the western Cantabrian Mountains, their last refuge, has been reduced by at least 90%. The Cantabrian population of capercaillie is considered, like the Pyrenean one, to be critically endangered.

There are several factors that may have contributed to this decline, but it is probable that hunting, whether legal (until 1979) or illegal, was the main one. “Since the middle of the 20th century, around 7,000 capercaillies have been hunted, mostly males. This is an exhuberant number if we think that there were less than 200 individuals in the Cantabrian mountains in 2019”, says Miguel Clavero, lead author of the study. But the factors that triggered the decline years ago, such as hunting, may not be relevant today.

Isolated populations that have been decimated may lose genetic diversity due to interbreeding between related animals, leading to genetic depression. The genetic depression may trigger an extinction vortex, a process that is independent from the initial threats. This is a self-fuelled phenomenon, in which the negative effects of inbreeding (on reproduction, survival or both) generate population losses, which in turn worsen inbreeding and lead to further declines.

The extinction vortex and the genetic rescue

Is the Cantabrian capercaillie caught in an extinction vortex? The genetic diversity of the Cantabrian capercaillie is notably low and many individuals have high kinship levels. But identifying low genetic diversity is not enough to infer inbreeding depression, as depression must result in a loss of biological potential. To investigate these possible effects, the research team compiled, from many different sources, data on 32 clutches located in the field between 1950 and 2020. “In 70 years, the number of eggs per nest has decreased by more than half, from almost 10 to just over 4”, explains Javier Naves, researcher at the Doñana Biological Station and coauthor. In addition to the decrease in the amount of eggs detected in the field, there are also problems with captive breeding, such as low laying and hutching rates and the very high mortality of chicks.

Currently, different management actions are being developed to stop the decline of the Cantabrian capercaillie. “But these works are not helpful if something in the animals themselves does not work anymore. And there are very solid indications that this is happening. In fact, the population has not responded positively to any of the actions undertaken and genetic rescue seems to be necessary. This implies translocating individuals from other populations”, explains Miguel Clavero. This operation, already successfully tested in birds related to the capercaillie, seeks to increase genetic diversity and mitigate the negative effects of inbreeding. It is not a simple operation, as it faces significant technical challenges. The management inertia, based on the belief in the uniqueness of the Cantabrian capercaillie, exacerbates these challenges.

The putative exclusivity of the Cantabrian subspecies of capercaillie has been so widely emphasized that the idea of mixing with individuals from other populations has never been seriously considered. Now that it is known that the Cantabrian capercaillie is not so exclusive, that its subspecific status does not hold true and that inbreeding depression may make the population unviable, it only remains to see whether genetic rescue can restore the population's status or reproductive potential. "In general, it is assumed that the uniqueness of a subspecies will be positive, as it would encourage conservation efforts, but instead has worked as a trap for the Cantabrian capercaillie," concludes Miguel Clavero.

Reference

Clavero, M., Naves, J., Lucena-Pérez, M., Revilla, E. (2024). Taxonomic inflation as a conservation trap for inbred populations. Evolutionary Applications. DOI: https://doi.org/10.1111/eva.13677

Las características del hábitat determinan la presencia de parásitos de la malaria aviar en mosquitos

outreach@ebd.csic.es — Fri, 30 Aug 2024 12:51:08 +0000

22 May 2024

Habitat characteristics determine the presence of avian malaria parasites in mosquitoes

A scientific team led by the Doñana Biological Station – CSIC has revealed that the prevalence of avian malaria parasites in mosquitoes was higher in areas farther from saltmarshes and rivers

After analysing over 16,000 mosquitoes, the team found that the richness of avian malaria parasite lineages was greater in natural environments compared to rural areas

Common mosquito (Culex pipiens). Photo: Josué Martínez de la Puente

A scientific team from the Doñana Biological Station – CSIC, the University of Granada and the Mosquito Control Service from the Huelva Provincial Council has analysed the presence of avian malaria parasites in the common mosquito with molecular techniques. The study, published in the journal iScience, was conducted in localities in the provinces of Seville, Huelva, and Cádiz in southern Spain with different land uses. The aim of the study was to determine if habitat type influenced the presence of avian malaria parasites.

The team analysed over 16,500 mosquitoes, which were grouped into more than 750 pools of common mosquitoes (Culex pipiens). In total, parasites were found in 32,7% of the mosquito pools, including 13 different genetic lineages of avian malaria parasites of the genus Plasmodium. This supports the significant role of this species as a potential vector of a wide range of this genus lineages. Martina Ferraguti, first author of the study and Ramón y Cajal researcher at the Doñana Biological Station, explains, “We find higher Plasmodium richness in natural than rural areas, suggesting that habitat characteristics notably impact the diversity of parasites circulating in mosquitoes in southern Spain”. The team also found that Plasmodium prevalence and richness in mosquitoes were higher in areas farther from marshes and rivers.

The common mosquito, a key vector species of avian malaria

Culex pipiens is a common species in Spain, involved in the transmission of different pathogens. Studying the transmission dynamics of avian malaria parasites can help to understand the environmental factors that influence the epidemiology of vector-borne diseases in nature.

According to Josué Martínez de la Puente, a researcher at the Doñana Biological Station, “Our studies have shown that the common mosquito plays a significant role in the transmission of avian malaria parasites”. These parasites naturally circulate in nature and infect birds through mosquito bites. While aian malaria affects bird health, reproductive success, and survival, but it does not pose any danger to humans.

The results have been obtained within research projects funded by the Junta de Andalucía (Andalusian government) (P11-RNM-7038), the Organismo Autónomo Parques Nacionales (PN2022-2945), and the Leonardo Grant of the BBVA Foundation. This study is a fundamental step in understanding how environmental characteristics affect the epidemiology of mosquito-borne parasites.

Reference

Ferraguti M, Martínez-de la Puente J, Ruiz S, Soriguer RC, Figuerola J. 2024. Landscape and mosquito community impact the avian Plasmodium infection in Culex pipiens. iScience. 27(3):109194. doi: https://doi.org/10.1016/j.isci.2024.109194

Describen nuevas especies de insectos acuáticos que habitaban en las selvas prehistóricas de Australia

outreach@ebd.csic.es — Tue, 27 Aug 2024 09:51:34 +0000

27 August 2024

Scientists describe new prehistoric aquatic insect species living in the ancient forests of Australia

In 2022, the scientists, led by the Australian Museum in Sidney participated in the discovery of a spectacular Lagerstätte in Australia. This study provides the first detailed analysis of the community of aquatic insects from this deposit

The study provides new information about what the insects of Australia were like before the continent went through a process of aridification

Larva of Slidaea // Viktor Baranov

A scientific team led by the Estación Biológica de Doñana – CSIC has described for the first time one new species and several morphotypes of aquatic insects from the Miocene Epoch found in the McGraths flats, in New South Wales, Australia. The Australian Museum Research Institute and the University of Canberra have collaborated with CSIC on this study, which was published in the journal Papers in Palaeontology

Findings of the study shed new light on the long term changes in Australian climate and biota. Today, a large part of Australia is arid, with vast extensions of shrublands, grasslands and deserts. However, in Miocene, between 16 and 11 millions ago, the region was dominated by mesic (wet) forests. Today, due to changes in temperature and rainfall, these wet environments only exist in small patches in the north of the continent, close to the coastline. “A lack of well-preserved fossils has made it difficult to study climate and biota of Australia”, explains Viktor Baranov, a researcher at the Doñana Biological Study and first author of the study.

It was in 2022 when a scientific team, led by the Australian Museum’s Curator of Palaeontology, Dr. Matthew R. McCurry and including Dr. Baranov and many other colleagues, revealed an extraordinary discovery. In central New South Wales, eastern Australia, Nigel McGrath found a great variety of unique rocks on its property. Fossil organisms were visible, as if printed, on the rocks. After several rounds of excavations, scientists confirmed that they were in the presence of one of the most spectacular Lagerstätte, (deposit of fossils rich with the remnants of the soft-bodied organisms) in the world, named McGrath Flat after its discoverer. Deposit’s fossils are exceptionally preserved a rich diversity of plants, insects, spiders and vertebrates. This discovery enabled scientists to deepen their understanding of the organisms that once lived in the region before the Miocene’s cooling and reduced rainfall led to the disappearance of wet forests.

Chaoborus abundans reveals how fossilization process may occur

The new paper is the result of Baranov’s field work and collection work in the Australian Museum in early 2020. The team have identified one new species of Chaoboridae or “phantom midges”, named Chaoborus abundans after its great abundance, with thousands of larvae and pupae found in the McGraths Flat deposit. Likewise, they have described several morphotypes of other groups of aquatic insects. The team have found three new morphotypes of family Chironomidae (non-biting midges), one of Limoniida (Crane flies) and another one of Sialidae (Alderflies).

Details of adult male of Chaoborus abundans // Viktor Baranov

In addition to taxonomic results, the fossils have also provided some clues about the ecology of the animals from McGrath Flat. Representatives of the genus Chaoborus were especially informative, as their abundance allowed detail analysis of the species’ morphology and development (ontogeny). “We have shown that all four larval instars of the Chaoborus were present in the fossil record of McGraths Flat. That indicates that fossils were deposited in-situ rather than brought by water from elsewhere”, says Viktor Baranov. “This is important, because Chaoborus representatives have rather well-defined ecological preferences. Their larvae tend to live in the standing water-bodies with little to no fish. This ecological preference of the Chaoborus larvae, tells us about the kind of environment in which the preservation of the fossils happened – a small lake, or likely an oxbow”

McGrath Flat, a window into the past and the future

Fossils of McGraths Flat serve as a window into a unique time in the history of the Earth – the Middle Miocene Climatic Optimum – warm and wetter period that followed with gradual cooling and drying of the planet’s climate. Australian climate has been getting drier and drier ever since, but at much higher rate as of late, due to the climate change. With this study of this fossil deposit, scientist can better understand the impact of aridification of natural ecosystems over large periods of time, a task that is pertinent to understanding future changes in the environment.

“Spain in particular is grappling with aridification of many areas. In these conditions, observing progression of environmental change in the past, is one of the best tools we have to estimate where our own environment, agriculture and societal adaptations are heading in the future”, points Baranov. “The fossils of McGrath flats are more than just traces of the past, they are the proverbial canary in the mine, showing us, how lush forest turns to dry, semid-deserted grasslands. Hopefully, being more informed about long-term effects of aridification will make us more prepared to deal with its consequences.”

Reference

Viktor Baranov, Michael Frese, Robert Beattie, Tara Djokic, Matthew R. McCurry. New aquatic insects form the Miocene of Australia with notes on the ecology and ontogeny of a new species of Chaoborus (Diptera, Chaoboridae). Papers in Palaeontology. https://doi.org/10.1002/spp2.1580

Matthew R. McCurry, David J. Cantrill, Patrick M. Smith, Robert Beattie, Mary Dettman, Viktor Baranov, Charles Magee, Jacqueline M. T. Nguyen, Marnie A. Forster, Jack Hinde, Ross Pogson, Helen Wang, Christopher E. Marjo, Paulo Vasconcelos, Michael Frese. A Lagerstätte from Australia provides insight into the nature of Miocene mesic ecosystems. Science Advances. https://doi.org/10.1126%2Fsciadv.abm1406

El aumento de la temperatura acelera el desarrollo de los insectos neurópteros

outreach@ebd.csic.es — Mon, 26 Aug 2024 09:06:40 +0000

23 August 2024

Increasing temperature accelerates growth and development in lacewings

New study reveals higher temperatures are associated with an acceleration of growth and development in Neuroptera

Faster development in lacewings may be associated with lower survival and reproduction as temperatures warm

Nemoptera bipennis. Credit: Vanesa Castejón

Scientists from the Estación Biológica de Doñana - CSIC performed a scientific literature review to find out how temperature influences development in insects. Specifically, the research has focused on Neuroptera, predatory insects that play an essential role in ecosystem pest management. How do the life cycles of these species vary and how much of this variation is explained by temperature?

The results indicate that higher temperatures are associated with an acceleration of growth and development in Neuroptera, along with increased metabolic activity, facilitating faster development of eggs, larvae and pupae. However, such faster development may be associated with lower survival and reproduction as temperatures warm. The results are in line with previous studies suggesting that high and low temperatures may decrease survival and reproductive output and thus population viability. For instance, if individuals develop faster and have relatively smaller body sizes, high temperatures may cause them more stress and cause females to suffer higher relative moisture loss, higher evaporation and overheating, which negatively affects their survival and reproductive function.

Important research in the face of climate change

Insects play an essential role in all ecosystems and are increasingly exposed to higher temperature extremes under climate change. Unlike birds or mammals, they lack the ability to maintain a constant body temperature and are very sensitive to variations in environmental temperature. To mitigate potential risks, they have developed mechanisms and molecular responses to different temperature conditions, which can influence their development and growth and lead to phenological alterations.

The results show that it is necessary to predict how not only charismatic species, but also less studied but very important animals for the functioning of ecosystems such as insects, respond to temperature conditions throughout their life cycle. Faster development times may not necessarily lead to higher abundances due to differential temperature responses across life cycle.

Reference

Hanna Serediuk, John Jackson, Sanne Maria Evers, Maria Paniw. Comparative life-history responses of lacewings to changes in temperature. Ecology and Evolution. https://onlinelibrary.wiley.com/doi/10.1002/ece3.70000

El mosquito tigre presenta una baja relevancia en la transmisión de la malaria aviar

77176912K — Thu, 25 Jul 2024 08:13:06 +0000

25 July 2024

The relevance of the tiger mosquito in the transmission of avian malaria is low

The researchers have analyzed the role of this mosquito as vector of avian malaria pathogens.

The tiger mosquito may play a minor role in avian Plasmodium transmission in the wild, likely due to its mammal-biased blood-feeding pattern

Asian tiger mosquito (Aedes albopictus) // James Gathany, CDC

Besides its relevant role in the transmission of several diseases affecting humans, the Asian tiger mosquito may not be so involved in the transmission of avian malaria. This is the conclusion of a recent scientific review published in the journal Animals where the impact of Aedes albopictus, the tiger mosquito, in the transmission of avian malaria pathogens has been assessed. This review, carried out by the Doñana Biological Station – CSIC, the University of Granada and the Lithuanian Nature Research Centre, highlights the expansion of the tiger mosquito’s distribution range to almost all continents and the potential alteration of the transmission dynamics of wildlife diseases. This work is part of the COST European Action WIMANET.

The Asian tiger mosquito is an invasive species with a wide current distribution range. In addition to being a nuisance due to its bites, this mosquito is a public health problem since it is a vector of several diseases affecting humans, such as dengue or Zika. Changes in its distribution area could facilitate the transmission of these diseases in the invaded areas, where most of the studies have been focused on diseases affecting humans. However, their role in the transmission of diseases such as avian malaria, affecting wild birds, is scarcely studied. The research team aimed at reviewing the information available to clear out the role of Asian tiger mosquitoes as vectors of these pathogens.

The reviewed studies, monitoring the presence of avian malaria pathogens in mosquitoes captured in the wild, showed a minimum infection rate, suggesting that, although the tiger mosquito is able to interact with these pathogens, its role as vector is limited. “We suggest that it may be due to its tendency to feed mainly on the blood of mammals, and not so much on birds,” explains Jesús Veiga, researcher at the Doñana Biological Station – CSIC and first author of the study. However, the number of studies exploring this possibility is small, and they have only been carried out in a few countries where this invasive mosquito is present.

This work also reviewed studies analyzing the development of avian malaria pathogens, genus Plasmodium, in the laboratory. A great variability was found depending on the species of pathogen involved. Species such as Plasmodium vaughani and Plasmodium circumflexum may not seem to be able to complete their development in the tiger mosquito. Others, such as Plasmodium gallinaceum seem to develop relatively well and even transmit effectively from one bird to another. Plasmodium gallinaceum significantly affects poultry and causes major economic losses due to the mortality of untreated birds, loss of meat quality, and reduction in egg production. Therefore, special attention should be given to the presence of tiger mosquitoes in these environments.

Por otro lado, en este trabajo también se revisaron los estudios que analizaron específicamente el desarrollo de los parásitos de la malaria aviar, del género Plasmodium, en el laboratorio, donde se encontró una gran variabilidad dependiendo de la especie de parásito que se tratase. Mientras que especies como Plasmodium vaughani y Plasmodium circumflexum no parecen ser capaces de desarrollarse en el mosquito tigre, otras como Plasmodium gallinaceum pueden completar su desarrollo e incluso transmitirse de manera efectiva de unas aves a otras. Plasmodium gallinaceum afecta de manera significativa a aves de corral y provoca graves pérdidas económicas debido a la mortalidad de aves no tratadas, la pérdida de calidad de su carne y la reducción en la producción de huevos. Por ello se debe poner especial atención a la presencia de mosquito tigre en estos entornos.

“However, the results obtained to date are limited to a few species and genetic lineages of avian Plasmodium, limiting the conclusions that we may reach for the role of this invasive mosquito in the circulation of avian malaria”, says Veiga. “This is especially relevant considering that there are more than 50 morphospecies and 1500 genetic lineages of avian Plasmodium.” Further studies considering other avian Plasmodium species and lineages are essential to forecast how the introduction of the tiger mosquito in new ecosystems may affect the epidemiology of avian malaria in nature.

This study was financed by the Spanish Ministry of Science and Innovation, the European Union, and other sources.

Reference

Veiga, J.; Garrido, M.; Garrigós, M.; Chagas, C.R.F.; Martínez-de la Puente, J. A Literature Review on the Role of the Invasive Aedes albopictus in the Transmission of Avian Malaria Parasites. Animals 2024, 14, 2019. https://doi.org/10.3390/ani14142019

ICTS-DOÑANA | El número de mariposas de pradera en Europa ha descendido casi un 30% en tres décadas

77176912K — Tue, 23 Jul 2024 12:20:29 +0000

23 July 2024

ICTS-DOÑANA | The number of grassland butterflies decreased almost 30% in Europe in three decades

Data from 18 EU Member States show that between 1991 and 2020, populations of 15 grassland butterfly species are experiencing major declines.

The ICTS-Doñana participates in this index with data collected in the Doñana Biological Reserve

European common blue butterfly (Polyommatus icarus) in the Doñana National Park // Credit: J. Manuel Vidal Cordero

Butterfly populations are characterised by year-to-year fluctuations, however long-term trends reveal their actual status. Between 1991 and 2020, the numbers of 15 typical grassland butterfly species declined strongly by 29.5%, according to data from 18 EU Member States. Although this indicator uses 1991 as a baseline, substantial decreases in species abundance, richness and diversity had occurred before this date. Data from the European Butterfly Monitoring Scheme (eBMs) has been used for this index. The ICTS-Doñana of the Doñana Biological Station – CSIC actively participates in this program by providing periodical monitoring data of butterflies in the Doñana National Park.

The main drivers of the decline in grassland butterfly numbers are agricultural intensification and changes in land use, such as habitat loss, fragmentation and degradation. Agricultural intensification entails high inputs of agrochemicals, including pesticides, which can dramatically reduce insect populations, including butterflies.

According to the European Environment Agency publishes this index, it is difficult to forecast how soon butterfly populations can recover, as they are influenced by a combination of socio-economic and environmental factors and policy measures. Although some measures set out in the Habitat Directive have helped some populations, the declines continue to occur both inside and outside of protected areas.

Index included in the new Nature Restoration Law

Butterflies react rapidly to changes in their habitats, hence they are a valuable indicator of the health of the environment and can help measure progress towards EU biodiversity targets. In addition, they play an important role in the functioning of ecosystems and provide a range of services. They pollinate crops and wild plants and serve as a food source for other animals throughout all stages of their life cycle.

This grassland butterfly index is included among three indicators in agricultural ecosystems included in the EU regulation on nature restoration, recently adopted. The member states have to select at least two of the three indicators, including indicators on the share of agricultural land with high-diversity landscape features and the stock of organic carbon in cropland mineral soil, to put measures aiming to achieve increasing trends before 2030.

Reference

Grassland butterfly index - EU aggregate, Butterfly Conservation Europe, European Butterfly Monitoring Scheme partnership, SPRING project. Data Set: https://ec.europa.eu/eurostat/databrowser/view/sdg_15_61/default/table?lang=en

Un estudio liderado por el CSIC evalúa el riesgo de la presencia de fitosanitarios en Doñana y Tablas de Daimiel

77176912K — Mon, 22 Jul 2024 08:29:28 +0000

22 July 2024

A study led by the CSIC evaluates the risk of phytosanitary products presence in Doñana and Tablas de Daimiel

• The study, the most comprehensive conducted to date, has revealed the widespread presence of pesticides, some of them banned since 2009, in both National Parks

• The compounds detected have an important environmental impact and may pose a high risk to aquatic ecosystems.

Doñana National Park has been suffering serious drought problems for more than a decade. However, not only the quantity of water is worrying, but also its quality. This has been reflected in a study carried out by researchers from the Spanish National Research Council (CSIC), which has detected the widespread presence of pesticides in both National Park of Doñana and Tablas de Daimiel.

This research, led by the Institute of Environmental Assessment and Water Research (IDAEA-CSIC), in which Doñana Biological Station (EBD-CSIC), the National Museum of Natural Sciences (MNCN-CSIC), and the Desertification Research Center (CIDE, CSIC-UV) have participated, aimed to evaluate the environmental impact of agricultural activities in the surroundings of these protected areas.

This work, published in the journal Chemosphere, is the most comprehensive study to date on pesticides in Protected Areas of Spain. It includes the analysis of over a hundred hydrophilic and hydrophobic pesticides in water and sediment samples. A risk assessment was also conducted to highlight the potential dangers to aquatic organisms from pesticide loads.

“Although the regulations of National Parks are the ones of the greatest legal protection, pesticides from nearby agriculture activities are affecting the living beings that inhabit them. In fact, a previous study by our group already indicated that the accumulation of pesticides in some species of birds in the Doñana National Park reduced their reproductive capacity,” says Ethel Eljarrat, IDAEA-CSIC researcher and lead author of the study.

Impact of agricultural activity

In the last few years, problems related to intensive agriculture have been found in protected areas due to its potential damage to wildlife. Another study carried out by the same research group had already warned of the presence of some pesticides, such as bifenthrine, a pyrethroid insecticide banned for agricultural use, in samples of birds' eggs collected in Doñana. These findings encouraged the continuation of the study to evaluate the level of contamination in water and sediments and to identify potential illegal practices in the agriculture developed in the surroundings of these protected areas.

The results show the widespread presence of phytosanitary products in Doñana and Tablas de Daimiel, although the levels are higher in Doñana. Pesticides prohibited since 2009 by the European Union for agricultural use have been found both in water and sediment samples. Although the presence of banned pesticides in sediments may be due to the persistence of these compounds in the medium, the detection of up to seventeen banned pesticides (such as chlorpyrifos, terbutryn or diazinon) in water samples would indicate recent use. It is also common to find other products that, even though they were suitable in 2021 when the sampling was carried out, cannot be used since 2022, such as oxadiazon or cyfluthrin, among others. “It is important to carry out more studies like this that allow us to verify whether the new compounds introduced in the regulations of 2022 have been discontinued and, if not, act accordingly”, points Eljarrat.

“We observed the influence of phytosanitary products used in the surrounding crops in the contamination of Doñana and Tablas de Daimiel. This contamination in many cases shows that it can be dangerous for aquatic fauna and, above all, an important capacity to affect biodiversity”, summarizes Yolanda Picó, co-author of the study and researcher at CIDE.

Another interesting fact is the detection of higher contamination levels at certain points where the flow was lower at the time of sampling. “This highlights that water scarcity leads to increased contamination concentration,” says Miguel Ángel Bravo, conservationist at Doñana Natural Area and co-author of the study.

Risk assessment

The study also includes an assessment of the risk of the presence of pesticides for aquatic organisms, so the research provides valuable knowledge about the impact of agricultural activities in two protected areas. “Our results include the evaluation of potential risks of pesticide contamination in waters, but also in sediments, and suggest moderate to high potential risks at all sampling points in both National Parks,” indicates Ethel Eljarrat.

This study is part of the project “Impact of agricultural activities on wildlife in national parks (APAN)”, funded in 2017 by the then Ministry of Agriculture and Fisheries, Food and Environment under the Call for Research Grants in matters related to the Spanish National Parks Network.

Reference

A. Peris, Y. Soriano, Y. Picó, M.A. Bravo, G. Blanco, E. Eljarrat. Pesticides in water and sediments from natural protected areas of Spain and their associated ecological risk. Chemosphere. DOI: 10.1016/j.chemosphere.2024.142628

A. Peris, R. Baos, A. Martínez, F. Sergio, F. Hiraldo, E. Eljarrat. Pesticide contamination of bird species from Doñana National park (southwestern Spain): Temporal trends (1999–2021) and reproductive impacts. Environmental Pollution. DOI: 10.1016/j.envpol.2023.121240