Assessing species’ habitat associations from occurrence records, standardised monitoring data and expert opinion: a test with British butterflies

Accurate knowledge of species’ habitat associations is important for conservation planning and policy. Assessing habitat associations is a vital precursor to selecting appropriate indicator species for prioritising sites for conservation or assessing trends in habitat quality. However, much existing knowledge is based on qualitative expert opinion or local scale studies, and may not remain accurate across different spatial scales or geographic locations. Data from biological recording schemes have the potential to provide objective measures of habitat association, with the ability to account for spatial variation. We used data on 50 British butterfly species as a test case to investigate the correspondence of data-derived measures of habitat association with expert opinion, from two different butterfly recording schemes. One scheme collected large quantities of occurrence data (c. 3 million records) and the other, lower quantities of standardised monitoring data (c. 1400 sites). We used general linear mixed effects models to derive scores of association with broad-leaf woodland for both datasets and compared them with scores canvassed from experts. Scores derived from occurrence and abundance data both showed strongly positive correlations with expert opinion. However, only for occurrence data did these fell within the range of correlations between experts. Data-derived scores showed regional spatial variation in the strength of butterfly associations with broad-leaf woodland, with a significant latitudinal trend in 26% of species. Sub-sampling of the data suggested a mean sample size of 5000 occurrence records per species to gain an accurate estimation of habitat association, although habitat specialists are likely to be readily detected using several hundred records. Occurrence data from recording schemes can thus provide easily obtained, objective, quantitative measures of habitat association.

Conflicts of law and the mutual recognition of same-sex unions in the EU

My thesis uses legal arguments to demonstrate a requirement for recognition of same-sex marriages and registered partnerships between EU Member States. I draw on the US experience, where arguments for recognition of marriages void in some states previously arose in relation to interracial marriages. I show how there the issue of recognition today depends on conflicts of law and its interface with US constitutional freedoms against discrimination. I introduce the themes of the importance of domicile, the role of the public policy exception, vested rights, and relevant US constitutional freedoms. Recognition in the EU also depends on managing the tension between private international law and freedoms guaranteed by higher norms, in this case the EU Treaties and the European Convention on Human Rights. I set out the inconsistencies between various private international law systems and the problems this creates. Other difficulties are caused by the use of nationality as a connecting factor to determine personal capacity, and the overuse of the public policy exception. I argue that EU Law can constrain the use of conflicts law or public policy by any Member State where these are used to deny effect to same-sex unions validly formed elsewhere. I address the fact that family law falls only partly within Union competence, that existing EU Directives have had limited success at achieving full equality and that powers to implement new measures have not been used to their full potential. However, Treaty provisions outlawing discrimination on grounds of nationality can be interpreted so as to require recognition in many cases. Treaty citizenship rights can also be interpreted favourably to mandate recognition, once private international law is itself recognised as an obstacle to free movement. Finally, evolving interpretations of the European Convention on Human Rights may also support claims for cross-border recognition of existing relationships.