- Biodiversity in quarries
Typical quarry habitats and species
Mining sites as habitats
When extracting minerals, we change nature and the landscape. Our mining activities are handled with most care and take into account the existing biodiversity of the site. Indeed many animals and plants also benefit from our quarrying activities thanks to the large number of different habitats which develop during the quarrying activities.
These ecological niches offer animals and plants an area of retreat that they would rarely find nowadays outside our quarries. Some examples of these species are: Sand Martin, Bee eater, Eagle Owl and Peregrine Falcon, Yellow-bellied Toad, Natterjack Toad as well as the Bee Orchid and other rare orchids.
Before an area is cleared for quarrying, HeidelbergCement must pass an environmental impact assessment. A detailed after-use plan is part of the authorisation procedure and integrates new concepts of rehabilitation and renaturation. As a result of preserving and creating valuable habitats, the natural flora and fauna of the area surrounding the quarry is promoted.
Habitats with unique living conditions
In order to properly carry out the renaturation and rehabilitation of a quarry, it is important to be familiar with the individual habitats and their living conditions. The wide variety of habitats in which different animals and plants settle can be divided into the following groups:
- Wetlands (such as lakes or ponds)
- Open areas of rocky ground (rock faces or scree slopes)
- Wet meadow areas (such as bedding and wet meadows)
- Meager meadow areas (such as neglected, semi-dry, and dry grassland)
- Woody plant areas (e.g. hedges or bushes)
Wetland biotopes found in quarries are primarily formed by species of reed, tall perennial herb, and willow groves. Besides numerous species of snail, dragonfly, amphibian, and other insects, they offer breeding sites and sufficient food for specific bird species. Often concealed, ponds are particularly suitable homes for dragonflies and amphibians such as Yellow-bellied Toad, Warty Newt, and European Toad. Lakes act as a resting place and hunting site for birds such as Cormorants, Grey Herons and the Common Tern.
Rocky areas, steep rock faces, and protosoils (immature soils) in mining site provide a habitat for very specialised animal and plant species. For example, steep rock faces formed from unconsolidated rock are important breeding sites for bird species that build holes, such as the Sand Martin, or wild bees. Escarpments provide nesting places for rock breeding bird species such as Eagle Owls, Jackdaws and Kestrels, while endangered plant species – such as the Carline Thistle or Catsfoot – can be found on rocky knolls and scree slopes. Open areas of protosoil are valuable habitats for numerous species of birds, grasshoppers, ground beetles, and spiders, for example.
The combination of grasses and herbs is particularly significant for biological diversity, as these biotope types are found less and less frequently in the cultural landscape because of intensive use, drainage, or abandonment. Bedding and wet meadows represent valuable habitats for native animal species such as the Lapwing and the Whinchat, as well as for butterflies and grasshoppers. Amphibians, such as the common frog, also use the meadows as a summer habitat, as the moist to wet soil provides a good hiding place.
Meager meadow areas play important roles in maintaining the ecological balance. The diversity of their structure and species creates an important habitat for animals considered worthy of protection, such as wild bees, the Blue-winged Grasshopper, or the Sand Lizard. Certain plants like orchids or the Pasque Flower also find their ecological niche in these “extreme” locations. Because of their tolerance for dryness and a lack of nutrients, they are able to conquer a habitat that remains inaccessible to other plants. Humans also benefit from the (medical) herbs found in these locations, such as Arnica.
Woody plant biotopes in the middle of agricultural landscapes or large areas significantly increase the biological diversity. Many rare species like butterflies, beetles, reptiles and birds such as the Red-backed Shrike, or mammals such as bats need the woody plants as a protected breeding site and a base for hunting. The fruits of the bushes are an important basic food resource. Grasses and herbs at the edge of the woody plants and in the undergrowth are home to numerous insects that in turn provide food for other animals. In this way, even small woody plant biotopes result in large numbers of species.
In the ground layer of the wood, fungi, mosses, and low flowering plants form a habitat for insects, spiders, amphibians, and small mammals. The herbaceous layer, composed of grasses, ferns, flowering plants, and young trees act primarily as a source of food for game animals.
The third layer, the shrub layer, extends up to a height of approx. 3 meters, consists of bushes such as elder, hawthorn, and hazel, and is a source of food for the protected hazel dormouse as well as for birds and insects. The canopy or tree layer is the final and biggest layer; its translucency determines the structure and species diversity of the lower layers. It forms a habitat, for example, for birds of prey, bats, pine martens, squirrels, and insects.
Spatial changes in the extraction areas may create development zones for animals and plants. These zones are of various ages, have different structures, and are closely connected to one another (succession zones). Whenever minerals are extracted again from one of these areas, a replacement has already developed elsewhere. The biotopes, together with their animals and plants, that are affected by quarrying and have emerged as a result of quarrying therefore “wander“ back and forth across the quarrying site. These continually re-developing succession zones are called wanderbiotopes.
Wanderbiotopes allow enormous structural diversity to develop, enabling rare plant and animal species to settle in the area. Shallow, temporary bodies of water without vegetation or the tracks left by heavy-duty lorries, which can appear within a very short period of time during the extraction process, are typical wanderbiotopes for some amphibians such as the Yellow-bellied Toad or the Green Toad. During ongoing extraction activities, the Little Ringed Plover will happily settle on spacious areas of rock, gravel, or virgin soil that are almost free from vegetation, provided that there are at least temporary bodies of water nearby.