Major Threats to Wetlands
Threats to wetlands can be divided into two general groups those resulting from natural processes and those from human activities. This section will focus on the most common threats to wetlands as a result of human activity.
Being aware of the fact that they were entirely dependent on the proper functioning of wetlands and on the products and services they provide, ancient societies respected and protected their wetlands. Unfortunately, the increasing population pressure at the beginning of the last century, tightly interconnected with the growing need for food resources, and combined with a poor knowledge of the ecological functions of wetland ecosystems, put a very strong negative pressure on wetlands all around the world wetlands were regarded as "wasted lands" and even sources of disease. The rapid industrial development of North America and Europe at the beginning of the 19th century led to the present-day situation of wetlands being affected by human activities in their entire catchment areas (Commission Communication to the Council and the European Parliament, 1999). Moreover, the nature of the Earths atmosphere and hydrosphere spread the process of wetland pollution and deterioration all over the planet. The major threats to wetlands are considered to be (Commission Communication to the Council and the European Parliament, 1999; US Environmental Protection Agency, 2001):
Figure 16 Cleaning a canal during mating season, Menderes, Turkey (source the Convention on Wetlands website).
Figure 17 Dam construction on the Danube, Szigetköa, Hungary (source the Convention on Wetlands website).
Figure 18 Channeled section of the Mura river in Slovenia (source the Centre for Environmental Information and Education).
Figure 19 Unwise use of wetlands at Knoydard, Scotland (source the Convention on Wetlands website).
Figure 20 Industrial-scale peat mining (source the US Environmental Protection Agency website).
Figure 21 Agriculture and irrigation, Dadia Reserve, Greece (source the Convention on Wetlands website).
Figure 22 The Brazilian pepper (Schinus terebinthifolius) was first brought to southern Florida as an ornament. Now it destroys the habitat for wading birds by growing in tightly closed forests (source the National Wildlife Federation website on Non-Native Species).
According to the US Environmental Protection Agency, "[i]nvasive species are thought to have been involved in 70% of this century's extinctions of native aquatic species..." (US Environmental Protection Agency website on Invasive Non-Native Species).