Habitat characteristics and odonate diversity in mountain ponds of central Italy

1. In central Italy mountain ponds represent an important habitat for the conservation of dragonflies; however, human disturbance of these fragile environments is threatening the stability of their biodiversity. 2. Thirty-one ponds, ranging in altitude from 1014 to 2004 m, were qualitatively sampled for odonate larvae twice during 1998. On each occasion a range of physical, chemical and biotic habitat variables were also measured. 3. The mountain ponds sampled had fewer species of Odonata than lowland ponds, and there was a large presence of pioneer species. 4. Multiple regression analysis showed that the number of odonate species was positively affected by the amount of macrophyte coverage of the pond surface and negatively affected by increasing ammonium concentration. 5. A Canonical Correspondence Analysis revealed that species number decreased with altitude, chlorophyll a and phosphorus concentrations. The presence/absence of each odonate species was weakly related to the habitat variables. 6. The intensive use of ponds for livestock watering results in damage to the peripheral vegetation, which tends to cause high turbidity and lower macrophyte coverage of the pond water. The inevitable outcome in these situations is a reduction of the odonate diversity. Copyright © 2005 John Wiley & Sons, Ltd.