R. Holderegger et al., IS THE RELIC FLORA OF THE FALLATSCHE ENDA NGERED - CHANGES IN THE FLORA AND VEGETATION OF AN EROSION SLOPE NEAR ZURICH, Botanica helvetica, 106(2), 1996, pp. 209-225
The Fallatsche is an impressive erosion slope in the shape of a semici
rcular funnel in the vicinity of Ziirich. Its vegetation is characteri
zed by a succession series which starts on slopes of bare marl or calc
areous sandstone. These patches offer suitable habitats for early-succ
essional species and pioneers. The final serial stage is a sparse pine
forest. Intermittent erosion can interrupt the successional series at
any stage. In the resulting mosaic of various habitats we registrated
309 taxa of vascular plants and 48 taxa of bryophytes. They mainly be
long to species which are characteristic for pine forests (Molinio-Pin
etum), nutrient-poor meadows (Mesobrometum), and nutrient-poor fens do
minated by small sedges (Caricion davallianae), as well as to a group
of subalpine species. Many of them are mentioned in the Red List of va
scular plants of Switzerland. The comparison of the recent flora of th
e Fallatsche with its former flora (before 1970) by means of informati
on taken from literature revealed that only two plant species have dis
appeared from this location, but that the numbers of weeds, of ruderal
s, and of species indicating nutrient-rich conditions have increased.
This fact parallels a decrease in open habitat patches and an increase
of denser vegetation. Both phenomena are caused by the stabilizing ef
fects of protective measures like river breaks and possibly by aerial
nitrogen deposition. Despite its small area but due to its natural lan
dscape dynamics, the Fallatsche is a regional hot-spot for the conserv
ation of atonal vegetation in the northeastern Swiss Plateau.