[CT Birds] Trees on Charles island
sangari at yahoo.com
Fri Jan 6 03:07:47 EST 2017
We have asimilar problem in Doñana National Park, in southern Spain. There we havedocumented roosting and nesting colonies of different species (herons, eggrets,spoonbills) in big cork trees since the XVIII century. Only recently (last 50years) the nitrates and phosphates from the bird droppings are contributing tothe death of these trees.
We haveseveral factors playing together here; less photosynthesis, less efficient useof water from the tree due to the salts, reduced numbers of big trees (in theXVIII century the cork trees covered aprox 20% of the area with severalthousands of centenary trees; today only a hundred of century-old trees remain,some estimated to be 500 years old), increasing numbers of birds due toprotection and reduced predation, lower phreatic level (up to 20 mts in someareas) due to water extraction for agriculture (legal and illegal), increased temperatures and drought, and a fungalinfection (Phytophthora).
So, indifferent areas we see different causes, and depending on the subject toprotect (could be the birds, could be the trees, etc), there is a differentaction. I think that Winie has made a wonderful resume of the situation inCharles Island, and I fully support her conclusion, this is an opportunity toengage citizens about something that they see as “weird”. Knowledge is neverbad..
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