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Biodiversity at Linnaeus' birthplace in Stenbrohult, southern Sweden. 4. The vascular plant flora and its changes.

Biologisk mångfald i Linnés hembygd i Småland. 4. Kärlväxtfloran och dess förändring i Stenbrohults socken
Författare:
Redaktör:
  • Bengt Carlsson
Publiceringsår: 2004
Språk: Svenska
Sidor: 65-160
Publikation/Tidskrift/Serie: Svensk Botanisk Tidskrift
Volym: 98
Nummer: 2
Dokumenttyp: Artikel
Förlag: Svenska Botaniska Föreningen

Sammanfattning

We review the history of floristic studies of the parish of Stenbrohult, southern Sweden, where Carl Linnaeus was born in 1707 and spent his summers until 1728. Unfortunately, Carl Linnaeus never made a list of the wild vascular plants at his birthplace, although he mentioned at least 64 species from the parish of Stenbrohult in various manuscripts and books. However, he said that Stenbrohult was “a queen among the sisters” and had “rare and peculiar herbs, which at other places in Sweden are rarely or never seen” (translated from Linnaeus 1729). Many botanists have later visited Stenbrohult, but few have made any serious studies of the flora. Nils J. Scheutz (1854, 1864, 1871) added 57 less common species to the known flora of Stenbrohult and Fredrik Hård av Segerstad (1924) added 26 species. The first systematic study was made by Nils Johnsson, a medical practioner, mainly in 1922–32. He published some data in 1929, but a species list with a frequency scale was also deposited at Uppsala together with lots of collected specimens. Much of this material have been examined by Thomas Karlsson, The Swedish Museum of National History. The next systematic study was made by the present authors, mainly in 1970–74 but with some later additional data. The project “Smålands Flora” have also later contributed material, especially from many older collections in museums.
Our study was more thorough than previous ones, which make detailed comparisons to examine changes of the flora difficult. We divided the parish into 124 squares, each of them 1 ´ 1 km (UTM-grid), and almost all of them were searched during several hours at 2–3 visits spread over 15 May–September. For common species only presence were noted, and the number of squares where a species were found in 1970–79 is in the species list above noted directly after the species name. For each species we also add if we consider it likely (L) or possible (L?) that the species was established in Stenbrohult in 1728, when Linnaeus left the parish (cultivated species excluded, but escapes from cultivation included). We call such species linnaean species and estimate that there were about 600 such species in 1728. This estimate includes disappeared species that have never been reported and a few still undiscovered species, possibly at most 35 species. Among the vascular plant species/subsp. known from Stenbrohult about 78 are now considered locally extinct and 48 of these were probably present in 1728 (Table 1). This value of 8% disappeared linnaean species is too low, and we think that more than 10% is a more realistic figure, since some species disappeared before being recorded. Most of the known disappeared species occurred in managed meadows, pastures and cultivated fields (Table 3). During the last 150 years more than 99% of the meadows in Stenbrohult, cut for hay in July or later, have been abandoned and mainly converted to cultivated fields, pastures and forests. Ceased traditional management of meadows, dense spruce Picea abies plantations, artificial fertilisation of pastures and drainage of numerous small wetlands have been especially destructive to the flora.
Many species are at present on the verge of extinction or decreasing (Table 2) and we suggest measures that may save some of them. The most important measure is to expand the area of hay meadows cut after the middle of July, preferably also with grazing by cattle and horses after harvest. These animals are now mainly grazing former fields with a relatively species poor flora due to previous cultivation and fertilization. Grazing of shores of lakes and streams were formerly ubiquitous but are now rare which have effected the flora and caused some extinctions. However, the large Lake Möckeln is only a little polluted and still unregulated, which is positive for many species. Bogs continue to be exploited for peat up to the present time, with mainly negative effects on the flora. The species that have probably decreased and increased in Stenbrohult during the last 100 years are presented in Table 2, and the habitat distribution of the linnean species in Table 3.
During the last 250 years at least 221 species have immigrated to Stenbrohult, mostly still generally expanding species in southern Sweden, and often spread by man. However, at least 30 of these new species are now considered disappeared (Table 1). Some introduced dominating species, e.g. Holcus mollis, Arrhenatherum elatius, Lupinus polyphyllus and Spiraea species, have a negative influence on smaller species. Nitrogen coming with the precipitation add to their effects.
The extinction rate of linnaean species have accelerated over the years in Stenbrohult and since our study mainly was made about 30 years ago, we consider the time ripe for a new study. If it is made with our method a much better estimate of changes of the flora can be made than at present. We have also noted the precise location and sometimes the habitat and number of flowering individuals of less common species, which will facilitate determination of the causes of population changes in the future.
The flora and fauna of Stenbrohult is still very rich, e.g. with about 200 red-listed species recorded in recent times among the organism groups studied until now (Nilsson 2002, unpubl.). We consider the preservation of the linnaean species as a true tribute to the work of Carl Linnaeus, but to do this several urgent measures must be done. We suggest some of them in this flora, including habitat restoration and management.

Disputation

Nyckelord

  • Biology and Life Sciences

Övrigt

  • MISTRA and Lund university
Published
  • SUFOR
Yes
  • ISSN: 0039-646X

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