Monitoring's techniques of the wildlife: an in-depth analysis

The wildlife's monitorings and studies, within the protected areas, have a great value to the protection and the safeguard of the Island's natural heritage.

The wild species are difficult to sample and any counting must be considered as an approximate estimate of the animals' real number.

The various factors, which can effect the numerical estimation of the wildlife, are:

• the morphological and eco-etological of the different species (mobility, activities, etc.);

• the population's density and their spreading into natural habitats;

• the conformation of the interested area.

  As regards the types of counting, they can be distinguished in:
  - complete censuses (complete counting of the present animals in a determinate area and at specific time);
  - sample censuses (complete counting in a representative proportion in determinate area and at specific time);
  - counting per indices (index of presence, expressed as relative values for linear units or surface)

  In relation to the accounting, the censuses can also be:

  - direct countings in specified districts (direct and simultaneous observation carried out by operators that work within a defined area, along predetermined itineraries or from fixed locations using optical instruments);
  - direct searches along linear paths (the countings are realized along predetermined itineraries within an interested area by various means at constant velocity);
  - territories' mapping: direct or indirect searches along at an equal distance paths within an area of interest. The areas of animals' presence are signed on a map and they are useful to understand the species' spread and their vital areas;
  - capturing–re-capture: a small part of the population is captured, marked and released and then re-captured in order to count the marked animals;
  - indirect countings: searches of the presence signs in sample zones as indirect proof of the animals' presence, using acoustic methods as the listening of characteristics sounds (the song of bird, roar, etc.).