The richness of an area can be of general interest in the field of envi-ronmental planning and nature conservation, because a high richness stands for a high number of species living in the area under investi-gation. The species-richness is a good measure (indicator) of biodi-versity. Additionally information about the kind of species living there is very helpful: Endangered species can give reason for special protection of their habitats for example. Furthermore the species composition itself often inform about the kind and to a certain degree about the ecological quality of a habitat (Flade 1994).
As described above the Hassediagram of Figure 4 provides informa-tion about the species-richness of the churchyards as well as the spe-cies composition. The richness is mapped at four levels. The spespe-cies composition can be analysed by looking at the antagonistic indica-tors, which explain the incomparabilities between different yards.
Looking for example at the churchyards with the highest richness, one find the bird species which has been observed only in one of these three yards (Table 3). These differences in the species composi-tions are with a high probability caused by environmental structures, for example the kind of habitat of the yard, the surrounding area or the size of the habitat. Comparing the Yards No. 14, 19 and 28 for example there are ten species were only observed in yard no. 14, seven species only in yard no. 19 and three only in yard no. 28. Fur-thermore eleven species are observed in both yards no. 19 and no. 28 but not in yard no. 14. There are only 5 species living in both yards no. 14 and no. 28 but not in no. 19 and there are no species at all liv-ing in both yards no. 14 and 19 but not in 28. Figure 5 shows sche-matically the distribution of bird species among these three church-yards.
only: 14
only:
14 ∩ 19 ∩28
only:
19 ∩ 28 only:
14 ∩ 19
only: 28 only: 19
10 species
3 species
7 species
11 species
many species only:
14 ∩ 28 5 species
0 species
Figure 5: Schematical representation of bird species in 3 churchyards, 14, 19 and 28. In ellipses the churchyard-combinations are shown. In rectangles below the bird species which are inhabitants of that combination
From Figure 4 and 5 we deduce that 14 and 19 must be very specific with respect to the habitat conditions, whereas churchyard 28 allows a wide variety of birds.
Table 3: Example of unique species on churchyards. *: Bird of the Red List of endangered bird in Berlin.
Churchyard No. Species only observed in this churchyard
14 Bullfinch*, Linnet, Crested Tit, Dunnock, Raven*, Black Wood-pecker, Firecrest*, Coal Tit, Treecreeper, Goldcrest
19 Middle-Spotted Woodpecker*, Golden Oriole, Mallard, Marsh Warbler, Collared Dove, Tawny Owl, Wryneck*
28 Whitethroat, Common Buzzard, Long-eared Owl*
Thinking about species as indicators for certain habitats one can as-sume that the habitat of yard no. 14 should be somehow different especially from no. 19. Whereas the habitats of yards no. 19 and 28 seem to be more similar to each other because the number of common species is definitely higher. By looking at the species composition one finds that the habitats are of forest type. In yard no. 19 birds like the Marsh Warbler and the Mallard make it likely, that there is some water or marsh in the yard itself or in the nearby surrounding. Com-paring the species, which are unique for only one yard with the key-species (Flade 1994) that yard no. 14 should be mainly a coniferous forest riddled with broad-leafed trees. Yards no. 19 and 28 should be mainly deciduous forest. Species like the Magpie, the Common Red-start or the Tree Sparrow shows that the habitat can be classified as of settlement-type in general. Thus the difference between yard no. 14
deciduous) and (2) the influences of the settlement. In yard no. 14 these influences seem to be lower. These statements are confirmed by observation and are helpful if further management decisions are nec-essary. Looking at the species mentioned in Table 3 one can find six species which are members of the so called “Red List” of endangered breeding birds of Berlin. In Table 3 they are marked with a *. Despite the high level of richness, this fact also confirms the special quality of these three yards. As written above the habitat of yard no. 31 seem to be very special as well, as the yard is an isolated element. The reason is the presence of the Grey Partridge, which is also a bird of the Red List of endangered species of Berlin. The Grey Partridge and the Common Pheasant in this yard may lead to the assumption that the habitat or the nearby surrounding might be field-like. Analysing the species composition of the yards of the lowest level of richness, one can find only very common species like the Greenfinch.
The abundancies of the species can be visualised by a Hassediagram as well (Figure 6). The species, which has been found in many yards, are listed in the upper part of the Hassediagram, whereas rare species living only in a few areas are at the bottom of the diagram. As it is to be expected, the abundancies of the species of the 28 yards shows a good accordance with the statement of the Red List and general or-nithologic knowledge.
Trying to find the reasons for the high or low richness of the yards, it is very likely to examine the size of the yards should be examined.
Indeed in general there is good evidence as the three yards with greatest biodiversity are also the biggest in size and the ones of low-est richness are the smalllow-est. Of cause there are exceptions from this rule. Yard no. 9 for example belongs to the second level of richness but is relatively small, whereas yard no. 17 is quite large, but only at richness-level 3. Here the reasons should be searched in the sur-rounding area of the yards. Looking at the geographical position of the yards, it seems to be of minor influence if an area is located in the centre or the periphery of the city.
A
Ba Bm
B Bs
Dg Ei E
Fa Fe
F
Gb Gg
Gro Gp
Gim Gi
Gs Gf
Gue
Hf
Hr H
He Kb
Kg
Kl
Ksp K
Mb Msp
Moe
N Ne
P
Re
Rt
Rk Sm
Si
Sg
Hx S
Sti Sto
Sum
Su
Ts Tt
Wl
Wm
Za Zl
Figure 6: Extension of bird-species. Species with equivalent extensions are: (Hf, Kra, Sap, Wb), (Mb, Wo), (Msp, Wz, Wh), (Gim, Hm, Tm, Wg) and (Fa, Ku). Abbreviation of German names, for English and scientific names see Table 5.