I'm looking for a Ph.D. and I would like to know what are the European most active Research Centers in the fields of Landscape Ecology and Ecosystem Conservation/Restoration.
It's good to be in a happening place, but for a PhD, your advisor is at least as important as the department. I would suggest searching on European landscape ecologists who are doing excellent work. For example, have a look at European members of the editorial and advisory boards for Landscape Ecology (http://www.springer.com/life+sciences/ecology/journal/10980?detailsPage=editorialBoard).
Have a look at UFZ-Helmholtz centre for environmental research, Leipzig (Germany). There is a department of Computational Landscape Ecology. They do a lot of work on landscape ecology and ecosystem services. You would be tied to University of Halle or Leipzig, while working at UFZ.
It's good to be in a happening place, but for a PhD, your advisor is at least as important as the department. I would suggest searching on European landscape ecologists who are doing excellent work. For example, have a look at European members of the editorial and advisory boards for Landscape Ecology (http://www.springer.com/life+sciences/ecology/journal/10980?detailsPage=editorialBoard).
I agree with Graeme's opinion. Try to find an advisor who is working on a topic related to your research interests and see if there is common ground for a PhD topic. Chances are this will also lead you to the most active research Centres in Europe.
Perhaps geoecological perspective of landscape ecology is interesting for you and then I would suggest Institute of Landscape Ecology (Slovak Academy of Sciences).
UFZ is surely an option (I am working there ;-), with different departments covering different aspects from community ecology and consveration biology to economics and landscape ecology.
Other options in Germany could be: University of Bayreuth (geoecology), University of Lüneburg (integrated sustainability research), University of Hanover (Chair for aldnscape ecology, C. von Haaren) ...
As people never think to France, I recommend the teams from CNRS and INRA in the University of Rennes as a good example of what can be done in community ecology, spatial ecology and agricultural planning etc. I have very good contact with some colleagues which scientific production is very good.
I strongly agree with Graeme's opinion. In Europe is not like in the USA where we can identify strong Landscape Ecology labs. In Europe, is more up to individuals that are well known within the Landscape Ecology community, it depends also the applications you are looking and the scales of work. After serving for 8 years in IALE as Vice president, I will strongly advise that you take some time to visit some of the key landscape ecology sites and follow the links to the people that serve on the board and also the ones that serve within Landscape Ecology Journal. Look at their production and the fields of applications. You can also search in the Journal of Landscape Ecology for authors and country affiliation. For more info: http://www.landscape-ecology.org / http://www.iale-europe.eu/ - http://iale.org.uk/