Sorry Carl took me a little while to get back to you….you make some interesting points.
Of course not all the protected areas are suitable for European Turtle Doves many are mountainous or densely forested. Those that are suitable also are having a torrid time of it with encroaching agriculture, over grazing, reduced water levels (important for TDs) due to unsustainable crop irrigation, pollution, abandonment and poor management, issues of spray drift etc. For example – Doñana is a complete mess right now, much of it becoming unsuitable for many species including Turtle Doves – there is nothing sustainable, extensive or suitable for a protected area there, it is close to becoming some kind of messed up theme park!
In The Straits here there are many areas suitable for the species but there are expanding areas such as La Janda which are becoming ever more volatile for the species with a complete lack of food for them due to modern herbicides and intensive cultivation.
The species population is rapidly in decline, of up to 78%, throughout its distribution range in Europe (>93% in the UK!). The declines are especially pronounced in the European western migratory flyway of the species – so despite hunting in the Eastern med the declines in Balkan breeding populations are not as pronounced (one major difference being agriculture but changes there are now driving declines too!). Spain supports c.40% of the entire breeding population of the species in Europe and maybe 60-75% of the population use this migratory route.
At the same time there are positive trends in areas with complex and extensive farming and cultivation (small parcels, diverse coping, scrub, organic management etc) which reinforces the importance of extensive agricultural practices for this species.
If you ever get chance to visit La Brenne in France during May / June, the management of the area and its extensive agriculture is brilliant, as a result an early morning walk there is full with purring Turtle Doves ! (although intensive cropping is starting to encroach in the less forested and more open areas around the park hence why they lost Little Bustards!).