Monitoring of Temporary Ponds as Indicators of Environmental Quality

*Claudia Campanale, Vito Felice Uricchio and Carmine Massarelli*

### **Abstract**

Temporary ponds represent a specific type of ecosystem extensively widespread worldwide. They are better known as copular pools, ephemeral waters, karst sinkholes, seasonal wetlands, and vernal pools. Among these, Mediterranean Temporary Ponds (MTPs) represent a priority habitat according to the Natura 2000 network of the European Union. Their main characteristic is represented by their depth of only a few centimeters and lack of communication with permanent water bodies. MTPs habitats are vulnerable to human activities, especially agriculture, and they are considered priority habitats to safeguard. Threats affecting this habitat are various and many and depend on specific site conditions, including intensive agriculture, tree planting, abandonment of traditional land use, and excessive grazing. In the present manuscript, we report the results of monitoring activity of some of these sites in Southern Italy aimed at understanding the ecological status of these ephemeral ecosystems with a specially developed methodology based on data integration.

**Keywords:** temporary ponds, microplastic pollution, pesticides, data integration, GIS

#### **1. Introduction**

Temporary ponds are a common natural habitat, abundantly widespread in all biogeographical regions [1]. Other ecological studies indicate that temporary ponds are habitats of some biological importance because they can host a considerable number of rare and endemic species [2–4]. These habitat types are currently highly threatened. Almost all temporary ponds are shallow, and most can be easily destroyed by drainage works for agricultural or urban development purposes [5]. Their small water volumes influence their high susceptiblity to pollution [6, 7], including emerging pollutants such as microplastics (MPs) and pesticides [8, 9]. To these threats is added that deriving from a lack of awareness: even if located within protected areas, temporary ponds have not always been evaluated by professionals in the same way as other freshwater ecosystems better known as lakes, rivers, and permanent ponds. Consequently, the conservation of the temporary ponds has never been to the

attention of the administrators, and without any criteria, they have been destroyed over time for various purposes [2].

Among the threatening factors for these environments, we must also consider the ongoing climate changes on a global scale: it is probable that temporary ponds, with their delicately balanced hydrological regimes, are susceptible particularly to these changes and over a few years they could significantly reduce [10]. Another aspect of difficulty in providing correct information to the administrators of the territory to combine development needs with conservation criteria for these habitats is the lack of information.

Studies on temporary ponds are at least 50 years late compared to those of betterknown water bodies, so this article aims to propose a multidisciplinary methodology to carry out the monitoring of temporary ponds to identify the pressures that insist on the hydrographic basin and sub-basin of interest. Temporary ponds (**Figure 1**) can be defined simply, as "lentic water bodies with a recurrent dry phase" [1]. This description includes a large range of water bodies, including tiny puddles that can hold water for only a few days and water bodies subjected to dryness after a few weeks or years. Like other freshwater habitats, temporary ponds are also changeable: as the duration of the hydroperiod increases, they turn into semi-permanent ponds and dry out only in years of drought.

A distinctive feature of temporary ponds is that they can form almost anywhere, it is only necessary for water to accumulate in a depression in the ground and silt to prevent water from infiltrating underground quickly. Their ease of formation and, at times, their persistence over time means that they are present almost everywhere in different types of ecosystems, both of natural and non-natural origin. They can form as a result of small barriers created by the fall of trees as in depressions caused by man: vehicle furrows, quarry bottoms, etc.

Among the temporary ponds, the ponds located in the Mediterranean region, socalled Mediterranean Temporary Ponds (MTPs) [11] are classified as priority habitats according to the Natura 2000 network of the European Union (Natura code 3170, Habitats Directive 92/43/EEC). They are situated in many Mediterranean countries. They are categorized as "priority" due to their elements with a unique and important meaning for one or more living species. They include a peculiar flora composition,

**Figure 1.** *Some temporary ponds in the Puglia region (South Italy).*

#### *Monitoring of Temporary Ponds as Indicators of Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.107885*

succession stage, and/or structural factor. Since they are humid depressions, periodically subject to temporary seasonal submersions, they host plant communities of great richness and originality even if not very showy, they are rich from a floristic point of view with rare and exclusive species of these environments [12, 13]. Several temporary ponds in the Mediterranean region vary from small copular ponds 50 cm deep hollowed out in rocks to almost permanent lakes, sometimes covering more than several hectares. They present a consistent variability in size, shape, depth, biodiversity (flora and fauna), and time of flooding [14–18]. The increased urbanization and agriculture combined with climate change has led to the extinction of a vast number of temporary ponds in the Mediterranean region [18].

Temporary Mediterranean ponds exhibit significant variability regarding the length of their hydrological period. They often form in karst areas and are in equilibrium with the aquifer, which in some circumstances can lead to a rise in the water level. In natural karst environments, the permeability and slope and other geological properties determine how much water the duration of the hydroperiod and therefore the composition of the ecosystem generated by the temporary ponds.

As temporary ecosystems, MTPs represent an important and sensitive transition between aquatic and terrestrial environments and act as retention basins for macroplastics and MPs [8]. However, only a very few works to date have investigated the presence of MPs in temporary ponds and in particular in mountain karst ponds [19], rainwater retention ponds [20–22], and sport fishing ponds [23], or small water bodies [24].

Mediterranean temporary pond habitats are very susceptible to anthropic pressures [25], due to their particular physical and ecological features. Their value is frequently overlooked [26, 27] due to their small size and seasonality.

In many Mediterranean temporary ponds, human activities create great pressure. However, the high biodiversity that can be found has been preserved thanks to balances with human activities that have become less and less impacting [12, 27].

The development of agriculture and urbanization in the Mediterranean region influence the health status of numerous sites with temporary ponds [27, 28].

The increase in urbanization in the Mediterranean region has led, due to urban expansion and connecting infrastructures, to the extinction of numerous temporary ponds. Inadequate management practices, such as soil removal, drainage, overgrazing, and intensive agriculture, have seriously endangered these fragile ecosystems [29].

Intensive farming practices can lead to significant changes in the catchment area. Since a large part of the territory is ploughed, consequently, an increase in erosion is induced and the transported sediments are increasingly filling the small depressions of the ponds, thus modifying the hydroperiod.

The same phenomenon always has another consequence, namely an additional supply of nutrients to the ponds, thus contributing to their eutrophication and a decrease in environmental quality.

Furthermore, the pollution of temporary ponds is increased by intensive agricultural activities due to the extensive use of pesticides and fertilizers. Not infrequently, there is also the abandonment of domestic and industrial and polluting waste (as in the previous image) [30, 31]. The overload of nutrients reaching temporary ponds is a widespread danger in the Mediterranean-macroclimate territories. This occurs mainly due to the fertilizers run-off from neighboring areas [32].

Temporary ponds can be used to understand the quality of the environment of the basin concerned as being small areas in which pollutants transported in run-off water

are deposited. So they can provide an assessment of the quality of the soil and water matrices of large areas by sampling at a single point and having some information about the places, also available from open-source databases [33]. Following this methodology, it is possible to use temporary ponds as indicators of quality and possible environmental degradation.
