Diversität der natürlichen Gebirgsvegetation Grönlands - "Artenvielfalt" im Niemandsland
Authors: Schwarzenbach Fritz H. , Kaiser Sigrid , Geißdörfer Rainer 
Published: March 2017

This study analyzes the diversity of the natural vegetation in mountains of eastern and northeastern Greenland. The botanical field-work has been done during the Danish East-Greenland Expeditions (leader Dr. Lauge Koch) in the summers 1948-1952, 1954, 1956, and during three iourneys
in the summers 1991, 1994 and 1995. The analysis is based on botanical observations in nine selected areas (calied "provinces A to I'~ between 70"30'N and 80"30'N. The total file has 9348 records (called "observations"). An "observation" says that at least
one plant of a certain species of vascular plants has been observed at a given place. The date of the observation, the topographical position, the altitude and the exposition of the place as weilas some information on the pheno/ogy of the plant, on the local vegetation and on the documentation
(photo of the plant or of the place, herbarium specimen) complete the individual records. A list of the most important variables is shown in Table 2. The records are grouped as nine subfiles corresponding to the provincesA to I. Within each subfile the numbers of observations/species are counted
and expressed as percents of the total number of recordslprovince. In a next step the observations of each province are grouped according to the altitudes of the places where the plants have been observed. The definition of these altitudinal zones H1-H8 is given in Table 3. The same table
shows the numbers of observations, of places and of species for the provinces and for the altitudinal subtiles. The diversity of the vegetation is based on the relative frequency of observations/species. This type of distribution is called "Arten/PräsenzVerteilung" (distribution
"specieslpresence"). The diversity of sampIes is estimated by three different indices: Shannon-Index (Sh-Index), Simpson-Index (Si-Index) and the Q-Statistic. The definitions and the algorithms for the estimation are given in Table5. The Sh-Index hasa theoretical maximum value fora
given combination "number of species/sample" and "number of observations/sample ". The maxima are reached when each species is evenly represented in the sampIe. The quotient "estimated indexlca/culated maximum of the index" gives a measurement of evenness and
is called "Maß für Ausgeglichenheit" with the symbol (V)-Sh. The results of the calculations are shown in Tables 6 and 8. The estimated values of the three indices have only a small variation between the provinces (Table 7). This result indicates that the diversity of
the natural vegetation in the mountains of northeastern and eastern Greenland has reached astate of equilibrium. The estimated values of all three indices are decreasing with the increasing altitude of observations. This effect is explained by the lower numbers of species and observations
at higher altitudes. The measurements of evenness (V)-Sh increase with increasing altitudes of observations (Table 8) showing a clear tendency to equal frequencies of species near the vegetation line. The same principle seems to be valid for other types of vegetation reaching the limit for
plant-life caused by another factor as, for instance, the vegetation of late-melting snow-patches. The diversity is higher in sampIes of lower altitudinallevels with high numbers of species. This tendency is explained by the fact that additional ecological niches are occupied by specialized
species of rare occurrence. A third principle influencing the natural diversity might be the influence of competition and selection in c/osed vegetation. This hypo thesis cannot be tested, however, due to the fact that types of c/osed vegetation are rare in the mountains of Greenland. The
results show that the so-called "optimal diversity" ofa natural vegetation in Greenlandian mountains cannot be predicted on a theoretical basis but might be estimated empirically, estimating the values for the Sh-index, the Si-index and the Q-statistic for the species/ presence distribution,
and calculating the measurements of evenness (V)-Sh.