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Sandpits in the landscape
The being of sandpits in many areas of The Czech Republic - it presents a phenomenon that determines in an enough high measure the character of landscape or forms a new landscape, many times different of the primary. The ecological functions of landscape are harmed in many cases for a long time within exploitation of gravel-sands on big surface of earth. Restoration of such areas calls for big financial resources and is often amateurishly made. It has not always to mean a change to the worse. Application of the spontaneous processes of succession for restoration of areas damaged by exploitation presents economically-advantageous alternative which is too attractive like preservation in comparison to the man-made reclamation made on big surface.
Sandpits like alternative habitat?
They are in many cases the very left extracted spaces which in the intensively-cultivated landscape of The Czech Republic furnish refugees for many plants and animals being even rare and protected. Moreover, they are also able to raise heterogeneity of the landscape and under certain conditions its esthetical value. Their main significance for protection of the nature is in existence of so called oligotrophic habitats characterized in that they have very low amount of soil nutrients. Just these are lacking in the recent landscape, because the supply of nutrients associated with people activity is large.
To the most important oligotrophic habitats of the left sandpits there belong the sand grasslands. They are by nature in this land on sand dunes. However, they die in the recent time in many areas because of increasing supply of nutrients and step-by-step sprouting of the competitively-more efficient species. In sandpits there are sands so called the initial habitats, i.e, places on where the first vegetation starts when exploitation was finished. The next important group from point of protection there are various types of wetlands in sandpits; they can be differently large lakes and pools, wet grasslands and peatlands, as well. They create on the places where sand is exploited below groundwater table, possibly, very close to it. Namely, in the second case they are in many cases very precious biotopes having a lot of rare and endangered species.
The sandpits happened too by important roosts of sand martin. These by law protected birds nested originally in the pulled down banks, but the ones due to river regulation almost had disappeared out of landscape. Now, they dig out their nesting holes almost steadily in cliffs of sandpits. The noise of exploitation does not mind them and so we can meet them very often in the spaces of recent exploitation. It is then important to focus exploitation out of nesting face up to the moment when the nestlings leave their nest. After that the best is the cliff to draw out so that the parasites of sand martin could not hibernate there, because these markedly decrease successfulness of nestling. Therefore the main problem of roosts in the old extracted sandpits is a paradox; how to fix regular renewing of the sheer nesting cliff. And moreover, outside the cliff there cannot grow any woods.
Dry grasslands having solitary trees and shrubs spring up in the sandpits, in particular, in drier and warmer regions of The Czech Republic by natural evolution. Growing of woods is limited in the first phase by low nutrients content in the soil, possibly too, by deficit of the around diasporas, and further by competition of other species, namely certain grasses like wood small-reed is. Special types are grasslands on initial habitats of gravel-sand pits. In them in many cases there dominates, for example, grey hair-grass together with next species badly putting up with competition, however, excellently naturalized for radical ecological conditions of sand grasslands.
Dry grasslands have many species of animals having been at one time in this landscape in great numbers, but thanks to people activity they are rapidly dying. In The Czech Republic it can be praying mantis, meloid beetles, tiger beetles and next ones. The grassland sandpits are also important for presence of reptiles; it holds namely for sand lizard or for viper. A lot of birds nest here, from the rarer species it can be red-backed strike or wheatear.
In the warmer regions at the restoration places damaged by exploitation there can be like problem black locust being alien, that often occupies large surface of sandpits and drive away the domestic plant species. If black locust grows around, you will have always to consider that can enlarge into extracted space.
Creation of wetlands is conditioned by exploitation below the groundwater table or very closed to it. The most precious biotopes are formed in the second mentioned case. The sandpits in this land are in many events alternative habitats for dying wetlands species. For protection of the nature the wetlands having pools are much more valuated than big continuous lakes. It is possible many times to make a compromise; one part of locality will serve for relaxation, whereas, the remaining one will yield good conditions for plants and animals.
As for the interesting species of plants you can find out in the sandpits with wetlands roundleaf sundew, buckbean, bladderworts of genus Utricularia or marsh clubmoss. The last mentioned specie uses even the sandpits like main surroundings for its presence. In the wetlands sandpits there found out good conditions, too, many species of invertebrates. Beside other they are some rarer species of dragonflies, reed beetles and next ones. The pools in sandpits serve often for reproducing amphibians including endangered species like common spadefoot, natterjack toad, European fire-bellied toad, European tree frog, great crested newt and others. From reptiles it is plentiful and protected grass snake. In the rushes there nest many species of water birds including marsh harrier which is protected.
Natural evolution in the most of dry and wet sandpits tends to forests. The length of time of this process and final composition species of woodland depend, besides conditions of habitat like wetness is, also on that, what species of woods are near around. The natural evolution in dry sandpits tends to deciduous forests being formed with mixture of woods like pedunculate oak, mountain ash, European ash, silver birch are; in many cases there are abundant shrub and herb layer. Composition of woods is presented, too, by coniferous trees like above all Scots pine or also Norway spruce is. The wetlands sandpits are characterized mainly by alder and willow carrs.
Fauna and flora of these forests is mostly similar to sylvan biotopes around. As rarer plants you can meet northern running-pine, possibly, snowline wintergreen, for example. Even if it is impossible to list the species being typical only for them, there exist a lot of animals that appear in such forests good conditions for life.
Up to prezent time in The Czech Republic man-made reclamation is the most frequent way of restoration. Unfortunately in this way we have woodlands that are not able to keep fundamental biological functions and offer good conditions only for very limited number of species. Such forests usually have shrub and herb layer very poor, in many cases completely is away. Largely they are monocultures of woods having identical age, dominating type is Pinus silvestris. For afforesting in some extreme cases there are used geographically alien species like northern red oak. Transport of soil and making organic layer on habitats being poor of nutrients - it is also fully unsuitable intervention which often contributes to enlargement of ruderal and alien species of plants.
It is clear that the previous text results in conclusion that the natural evolution forms biologically more valuable communities than man-made reclamation. In any case one must observe concrete conditions in situ. In some events it is recommended expediently to help to natural restoration, in particular, by planting geographically and habitat native plants. If you accept such planting, it should be plantings being varied in species with important contribution of leafy woods. The sandpits having been restored should not be in any way plantations for production of pine timber.