27 Nov. 2012 - Anna Visconti

Diversità trofica e fonti di carbonio a supporto della rete trofica pelagica del Lago Maggiore: il ruolo della stagionalità studiato attraverso l'analisi degli isotop stabili

Presenta: Anna Visconti*
Responsabili*: Marina Manca, Antonio Di Guardo e Riccardo de Bernardi
Collaboratori**: Amedeo Fadda, Rossana Caroni, Pietro Volta, Igor Cerutti
*C.N.R.‐Istituto per lo Studio degli Ecosistemi, Verbania Pallanza
**Università dell’Insubria di Como

Le variazioni stagionali della rete trofica pelagica del Lago Maggiore e il contributo delle fonti di carbonio litorale e pelagico sono stati indagati attraverso l’utilizzo dell’analisi degli isotopi stabili (SIA) di carbonio ed azoto prendendo in esame le componenti considerate più rilevanti: dalle fonti di supporto ai consumatori primari e secondari dello zooplancton, fino ai pesci zooplanctivori.

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15 Nov. 2012 - Manuel Lopez-Lima

Ecology, conservation and genetics of European freshwater mussels: challenges and opportunities

Presenta: Manuel Lopez-Lima (CIMAR-‐LA/CIIMAR and ICBAS,Porto, Portugal)

Freshwater ecosystems are at risk and invertebrates are particularly vulnerable. However, this situation is not recognized since major conservation efforts are directed to vertebrate species (particularly deserve conservation attention. Although some attention is been given to the situation in North America (particularly on unionid species) Europe still does not give too much attention to this faunistic group. Therefore in Europe there is an urgent need for a more integrated and holistic conservation approach on these taxa. Specific areas of research are required from taxonomy and systematics, through biological research (with emphasis on ecological aspects and life history traits) to more effective applied conservation and propagation strategies. This lecture presents the distribution and conservation status of freshwater bivalves in Europe and the research efforts of our team in the ecology and biology of freshwater mussels from densities and distribution through growth and host fish interactions to phylogeny and genetic diversity. The integration of all these data is regard interested groups, from local communities to governmental and European agencies for successful implementation

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20 Nov. 2012 - Anna Visconti

Interaction between cyanobacteria and gastropods of a fluvial lake of the St. Lawrence system (Canada)

Presenta: Anna Visconti*
Responsabili*: Antonella Cattaneo e Marina Manca
Collaboratori**: Antonella Cattaneo, Christiane Hudon, Levesque David, Wauthy Maxime
*C.N.R.‐Istituto per lo Studio degli Ecosistemi, Verbania Pallanza
**Université de Montreal

Following environmental perturbation, benthic cyanobacteria can become an important component of primary producers replacing chlorophytes, epiphytes and macrophytes. In some sectors of the St Lawrence fluvial lakes, the proliferation of the benthic cyanobacterium Lyngbya wollei was detected. To test the interaction between cyanobacteria and gastropods, substratum choice experiments and growth experiments were performed on different gastropod species exposed to L. wollei, chlorophytes and submerged vascular macrophytes.

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13 Nov. 2012 - Vincent Berthon

Using fossil diatoms and rotifer resting eggs to reconstruct past anthropogenic impacts on large lakes

Presenta: *Vincent Berthon
Collaboratori: Benjamin Alric*, Aldo Marchetto**, Emmanuelle Dormia*, Frédéric Rimet*, Marina Manca**, Marie-Elodie Perga*
* INRA – Thonon Las Bains, France; ** CNR-ISE Verbania, Italia

During the XX century, lacustrine ecosystems have undergone deep changes due to increased human activities. Although significant restoration efforts have been undertaken since the 1980es, their efficiency can be limited. For instance, although phosphorous concentrations of Lake Geneva have been cut by a factor of 10 in the last 30 years (for a total cost of four billlions euros), the algal biomass and the primary production remain as high as during the eutrophication maximum, even if water transparency increased. So, the counter-intuitive response of lakes to restoration measures emphasizes that although phosphorous concentration is a major driver of phytoplankton, there is a need to consider the interaction with other environmental drivers, such as climate or top-down controls. Our objective is to understand such scenario by investigating high-resolution paleolimnological data focusing on the planktonic communities (diatoms and rotifers) of three lakes (Geneva, Annecy and Bourget), disentangling the effect of changes in nutrient concentrations, fisheries management practices and climate change.

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6 Nov. 2012 - Francesco Santini

Specializzazione ecologica e radiazioni adattive nei pesci teleosti

Presenta: Francesco Santini (University of California Los Angeles)

Durante gli ultimi 5 anni recenti progressi nel campo della filogenesi molecolare e dei metodi comparativi hanno permesso le prime analisi quantitative della relazione fra specializzazione ecologica e radiazioni nei pesci teleostei, rivelando una relazione molto complessa fra habitat, ecomorfologia e cladogenesi. Durante questo seminario presentero' alcuni aspetti della mia ricerca sulla relazione fra invasione di nuovi ambienti e tassi di diversificazione nei pesci teleostei, con particolare attenzione alle transizioni fra ambienti di acqua dolce e ambienti marini, e fra ambienti di barriere coralline e ambienti costieri non di barriera nei percomorfi, il principale clade di teleostei. Verranno discussi alcuni dei meccanismi che possono permettere alle linee di invasori di radiare nei nuovi habitat, e alcune delle cause della mancata radiazione di altre linee

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