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Andy Green’s Research Activities

Past projects

Ongoing projects

Phd students

Postdocs

Other activities

SOME RECENT RESEARCH PROJECTS IN ANDY’S LAB

Population structure, dispersal and gene flow in Artemia: comparing native and exotic species.

The brine shrimp Artemia franciscana is native to the Americas but has been introduced into the Iberian Peninsula and other Mediterranean countries, where it threatens native Artemia species: the sexual A. salina plus a set of parthenogenetic clones often grouped as A. parthenogenetica. All these species produce resting eggs (cysts) that are readily dispersed by migratory waterbirds after passing through the digestive tract. Artemia provide an excellent model for the study of passive dispersal of invertebrates by birds, and we have compared the rates of dispersal of cysts of different Artemia species among bird species, localities and seasons. We also compared the population structure of each Artemia species across the Mediterranean region using mitochondrial and microsatellite markers. By combining the molecular data with data on bird movements, we gain insights into the extent to which dispersal by birds explains the genetic structure of each species of Artemia. Published results show that A. salina is highly structured with little contemporary gene flow between sites separated by >50 km. In contrast, diploid A. parthenogenetica have very little genetic variation and appear to have undergone a rapid expansion from a point of origin in Asia, consistent with their ready transport by birds.

Unfortunately, flamingos, shorebirds and other birds provide excellent vectors for the spread of the invasive A. franciscana. We have characterized the genetic diversity of A. franciscana in its introduced range, in order to determine the number of introductions and patterns of spread via waterbirds or other means. We also compared the levels of diversity with those observed in the natural range and in native Artemia species (publications in preparation). Our work on Artemia is in collaboration with Francisco Amat and colleagues at the Instituto de Acuicultura de Torre de la Sal, which houses an extensive collection of cysts from different populations.

Teal as major vectors of dispersal in the Camargue and beyond

This is the latest in a series of research projects in our lab on the role of waterbirds as vectors of passive dispersal, which remains one of our main research interests. In collaboration with several French institutions, we have studied the role of the population of Eurasian Teal Anas crecca wintering in the French Camargue in the passive dispersal of plants, invertebrates and parasites. By studying live-trapped and hunter-killed birds, as well as by conducting controlled feeding experiments in captivity, we found massive rates of internal dispersal of a variety of aquatic and semi-aquatic plants, including several alien species. Internal dispersal (endozoochory) was much more frequent for seeds than external dispersal (epizoochory), although there was less difference for invertebrate eggs. As well as massive transport within the Camargue, modelling of ringing data shows that teal are important vectors of long-distance dispersal across Europe for avian influenza viruses and many other organisms. We have found that teal have particularly intense interactions with seed shrimps (ostracods), dispersing them both as eggs and as adults that survive gut passage. Furthermore, teal carry cestode parasites that parasitize ostracods as their intermediate host, notably the cloacal cestode Cloacataenia megalops. Analysis of long-term ringing data from the Camargue shows that the prevalence of Cloacataenia in teal has increased steadily since the 1950s, for unknown reasons.

Lead poisoning in Andalusian wetlands

Together with Rafa Mateo’s team in the IREC, we have studied the distribution of Pb shot in the major wetlands in western Andalusia and the prevalence of Pb poisoning in different populations of waterbirds (especially Anatidae) and raptors. Anatidae (especially greylag geese) and raptors (including the Spanish Imperial Eagle) are affected by this problem in Doñana. As well as spent shot, the geese have been affected by the toxic Aznalcóllar mine spill of 1998. Hunting is now banned in most of the study sites, but Pb shot remain from hunting activities prior to protection in the 1980s. We found very high densities of Pb shot in the sediments of two Ramsar sites in Cadiz province: Laguna de Medina and Laguna Salada de Puerto de Santa María. We have studied how Pb is affecting the birds and other aquatic organisms (including terrapins and fish) in these lagoons, and identified ways to reduce the prevalence of lead poisoning in waterfowl by providing grit to reduce the rate of shot ingestion. We also monitored how geese and swamphens in Doñana were affected by the mine spill, throughout the first ten years after (up to 2008).

SOME ONGOING RESEARCH PROJECTS IN ANDY’S LAB

An ecogenomics approach to biological invasions of two crustaceans

In Europe, a range of invasive crustaceans have negative impacts on aquatic ecosystems. Among them, the American brine shrimp Artemia franciscana and the Asiatic oriental shrimp Palaemon macrodactylus are of particular importance due to their strong interactions with their European congeners (A. salina & A. parthenogenetica; P. longirostris). Both alien species have undergone major demographic and geographical expansions within a few years of arrival. Both are highly competitive under extreme environmental conditions (e.g. high salinity or low dissolved oxygen). This project, in collaboration with Ciro Rico, tests the role of higher physiological tolerance and enemy release in explaining the success of these invasive species. We are testing four predictions: (1) P. macrodactylus has been introduced repeatedly by commercial shipping traffic from source populations from two continents into multiple locations within Europe. (2) The two invasive crustaceans support higher levels of environmental stress than the natives. (3) Genes involved in the adaptive response to the new, invaded environment have differential levels of expression between native and invasive species. (4) Parasite release from their original area together with lower infestation rates by native parasites, and reduced expression of genes involved in parasite defence, enhances the fitness of invasive compared to native species. We are studying the geographical origin, number of introduction events and the structure of both the native and the invasive Palaemon species using microsatellites and mitochondrial markers (we already did this for Artemia in previous projects). Using eco-genomics, we are examining traits that might be under selection by identifying the genes involved in the stress response to environmental variables, and measuring the level of gene expression. We plan to experimentally manipulate temperature, salinity and dissolved oxygen levels in the laboratory and carry out reciprocal transplant experiments in the field to measure the response of native and invasive species, both in terms of survival and gene expression. We also aim to characterise parasitic infection in the wild and measure the levels of expression of genes such as the proPhenolOxidase which are involved in the response to parasitism.

Interactions between brine shrimps Artemia, waterbirds and their cestode parasites

Brine shrimps (Artemia spp.) are intermediate hosts for 14 cestode (tapeworm) species, which are parasitic in aquatic birds as adults. For some years now, we have been collaborating with Boyko Georgiev and his group in Sofia on the study of complex interactions between the species of the genus Artemia and their cestode parasites. These interactions have a major impact on hypersaline wetlands by changing the spatial distribution, metabolism, fecundity and survival rate of the dominant zooplankter (Artemia), as well as its availability as a feeding resource for waterbirds. In addition, these interactions may have a key role in regulating the biological invasion of the American brine shrimp Artemia franciscana in Europe, by influencing its competitive interactions with the native species Artemia salina and A. parthenogenetica. Because they were introduced as cysts, A. franciscana escaped their natural cestode parasites, and suffer much lower rates of parasitism in Spain than the native Artemia. We are currently studying the seasonal dynamics of cestode infections in native and exotic Artemia species in the Iberian Peninsula. Together with Juan Aguilar Amat and other colleagues, we are also studying the tritrophic interactions between black-necked grebe Podiceps nigricollis, A. parthenogenetica and their cestode parasite Confluaria podicipina in the Odiel marshes where grebes concentrate to moult and feed on Artemia. The parasite causes a bright red coloration in infected Artemia, owing to an increase in carotenoid pigments, thus providing a benefit to the grebes that may compensate for any cost of parasitism.

Restoration ecology of the fauna and flora in the Caracoles estate: colonization of new ponds

The Caracoles estate is an area of 2,700 ha of marshland within the Doñana area that was drained for agriculture in the 1960s. As part of the Doñana 2005 project for the restoration of the Doñana marshes, this area was incorporated within the Doñana National Park in 2004, and has now been restored into seasonal marshes that have recovered their natural hydrological connectivity with surrounding areas. We are investigating the ecological processes involved in the restoration of plant and animal communities in these Mediterranean marshes, and comparing them with a series of reference sites. The priorities for our lab are the study of plankton, macroinvertebrate and waterbird communities. We are concentrating on the colonization of a network of 96 new, seasonal ponds made within the marsh by removing 30 - 60cm of topsoil in 2004-2005. Our work on planktonic communities has partly been carried out within the framework of the Eurocores Biopool project coordinated from Belgium. We are working on the metacommunity ecology of these ponds, as well as the population genetics of some zooplankters and the importance of avian vectors in the arrival of new species to the ponds. In a new PhD project, we are paying special attention to the colonization of these ponds by the alien bug Trichocorixa verticalis.

Ecology of the glossy ibis in Doñana.

Doñana holds the largest breeding colony of glossy ibis (Plegadis falcinellus) in the west Mediterranean. Breeding only began in 1996, but now we have several thousand pairs. Jordi Figuerola, myself and our PhD student are studying the breeding ecology, survival rates and dispersal, taking advantage of an annual ringing programme. Habitat use is also being investigated both during and outside the breeding period. There is a strong relationship between the productivity and survivorship in the ibis population and the fluctuations in water level in the Doñana marshes. We have studied the diet, and founding the breeding colony to be heavily dependent on aquatic beetles and dragonflies. The ecological consequences of a marked sexual dimorphism in this species are also being investigated. If you read an ibis ring, please send an email to anillamiento@ebd.csic.es

Restoration of Laguna Medina

Laguna Medina near Jerez de la Frontera is semi-permanent and the second largest (108 ha) natural closed-basin lake in Andalusia. It is a Ramsar site and a Natural Reserve, famous for its threatened waterbirds. Its biodiversity value was heavily impacted by the introduction of carp , but these were eradicated in late 2007 using rotenone. At the same time, some of the arable fields close to the lake were restored to natural vegetation. Using both remote sensing and traditional limnological methods, we are studying how these restoration measures are changing the water quality in the lagoon, as well as the planktonic communities and the rates of sedimentation. We have also quantified the historical changes in land use and hope to conduct a paleolimnological study.

Interactions between flamingos and microbial communities in saline wetlands

In a new project in collaboration with Isa Reche at the University of Granada, we are applying molecular techniques to analyze microbial communities in saline wetlands across the Western Mediterranean region, and studying the role of the Greater flamingo in the metacommunity dynamics of aquatic bacteria and viruses. Flamingos are excellent long-distance dispersers of plants and invertebrates (e.g. Ruppia or Artemia), but their significance for microbe dispersal remains unexplored. Flamingos typically represent the majority of avian biomass in saline wetlands, and extensive ringing data and satellite tracking provides a unique understanding of their movements between wetlands. Our main goal is to determine the influence that dispersal via flamingos has in microbial gene flow and in shaping microbial metacommunities. We will also assess the effect that guanotrophication, due to the extremely high concentration of flamingos during breeding in colonies, has on microbial communities.

PHD STUDENTS WORKING WITH ANDY IN THE PAST AND PRESENT (Pdfs of theses available on request)

Jordi Figuerola completed his PhD on “The role of waterfowl in the passive transport of aquatic organisms: from local processes to long-distance dispersal” in 2002. Jordi now has tenure in our Department of Wetland Ecology.

Cristina Fuentes completed her PhD on the ecology of the Marbled Teal Marmaronetta angustirostris and White-headed Duck Oxyura leucocephala in El Hondo and Salinas de Santa Pola, Alicante in 2005. This included extensive work on the invertebrate and aquatic plant communities.

Marta Sánchez completed her PhD on “ecological relationships between waders and aquatic invertebrates in the salines of the Odiel marshes” in 2005. After completing a postdoc on host-parasite relations at CNRS in Montpellier, Marta is back with us at the EBD.

Violeta Muñoz completed her PhD on the study of genetic introgression between the White-headed Duck and North American Ruddy Duck in 2005, and is currently at Uppsala University.

Héctor Rodríguez-Pérez completed his PhD on the effects of waterbirds on macrophytes and invertebrates in Doñana in 2006, and is currently at the Tour du Valat in the Camargue. His work was centred on a series of exclosure experiments to study the effects of flamingos and other waterbirds on macrophytes and invertebrates.

Joaquin Muñoz completed his PhD in 2009 on the population genetics of Artemia in the Mediterranean region, including the native sexual A salina, native parthenogenetic clones and the invasive A. franciscana introduced from North America. He is a postdoc in our department, and remains interested in zooplankton.

Mónica Martinez-Haro completed her PhD in 2010 on heavy metal contamination of waterbirds and other aquatic fauna in Western Andalusia, and did her lab work with Rafa Mateo at the Instituto de Investigación en Recursos Cinegéticos in Ciudad Real. The main focus of her thesis was the impact of historical lead shot contamination in Laguna Medina at Jerez de la Frontera.

Anne-Laure Brochet completed her PhD in late 2009 on the movements of teal Anas crecca in the French Camargue, and their consequences for the dispersal of seeds, invertebrates and pathogens. She was based at Tour du Valat, and worked in the framework of an extensive ONCFS teal project.

Cecilia Calabuig completed her Phd in 2010 on the conservation biology of Coscoroba swans, with special emphasis on the impact of collisions with power lines. Her main director was Miguel Ferrer.

Simone Santoro started his Phd in 2008 on the population ecology of glossy ibis (especially mark-recapture analysis of the Doñana population) and is co-directed by Jordi Figuerola.

Cristina Coccia started her PhD in 2009 on the metacommunities of macroinvertebrates in restored marshes in Doñana, and the invasion biology of alien bug Trichocorixa verticalis.

POSTDOCS WORKING WITH ANDY, PAST AND PRESENT

Dagmar Frisch has done extensive work on zooplankton ecology in Doñana, and is now collaborating with us on Artemia genetics, but since September 2010 is based in Larry Weider’s lab in Oklahoma).

Anna Badosa came to work with us on zooplankton ecology and genetics in restored marshes in Doñana in 2007, straight after completing her PhD at the Universidad de Girona.

Christophe Lejeusne has a JAE postdoc to work on the genetics and genomics of Palaeomonid shrimps, especially the invasive Palaeomon macrodactylus. He has previously worked on cave shrimps and sponges in Marseilles and Ontario.

Marta Sánchez has a Juan de la Cierva postdoc and is working on relations between native and alien Artemia, their cestode parasites, and their avian final hosts.

TECHNICIANS WORKING WITH ANDY

Raquel López is focusing mainly on the restoration project and limnological monitoring for Laguna de Medina, Jerez de la Frontera.

OTHER ACTIVITIES THAT ANDY IS INVOLVED IN

Andy has been heavily involved in the IUCN-SSC / Wetlands International Threatened Waterfowl Specialist Group since its creation in 1990, and was Chair of the group between 1992 and 1999. This group exists to promote conservation of the globally threatened species and subspecies of Anatidae (ducks, geese and swans).

Andy is a board member of the international NGO Wetlands International.

Andy is a member of the scientific committee for the Ministry of Environment’s Doñana 2005 project for the restoration of the Doñana marshes.

Andy represents the Ministry of Science and Innovation on the Andalusian Wetlands Committee

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Updated September 2010