Human disturbance

Powerpoint presentation with findings of a 4 week vegetation fieldvisit on Saba:

• what is vegetation (research)?
• historic findings (1956 and 1999)
• current findings (49 repeated plots, 28 additional plots)
• preliminary results for different zonation belts
  • elfin forest (highest zone)
  • elephants ears scrub
  • transitional forest
  • dry tropical forest
  • grasslands, shrubland and coastal cliffs (lower zone)
• conclusions
  • elfin forest far from 'original'
  • zonation 2,3 and 4: no big changes, some expansion of elephant ears, more forest succesion resulting in more closed vegetation and poorer in bio-diversity
  • invasive species are more abundant in the lower zone: coralita, rubber vine,'india grass' and others

Abstract:

Recent surveys for the Snowy Plover (Charadrius alexandrinus) on St. Martin reveal that the species is no longer a resident on the island. Following surveys from 1997–2005, when the species was annually detected and observed breeding, plovers were no longer observed on the island. Both human disturbance to nesting birds and predation by invasive species are potential causes of the extirpation.