Reproductive differentiation in a Saxifraga hirculus population along an environmental gradient on a central Swedish mire

• Published in: Ecography
• Main Author: Ohlson, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1986
• Subjects: Ecology, Evolution, Behavior and Systematics; Saxifraga hirculus
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1986.tb01210.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1986.tb01210.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1986.tb01210.x

The perennial herbaceous mire plant Saxifraga hirculus was studied in different population densities along an environmental gradient on a mire in central Sweden. Tests were made whether the habitat conditions influenced the balance between vegetative growth of runners and seed production. Along a 30 m long transect the gradient was analysed for vegetation, hydrology, temperature and contents of ions in groundwater and surface peat. Three main zones were distinguished, a spring area, a rich fen area and an intermediate fen area. Range in concentration of ions in groundwater along the transect (mg 1 −1 ): Ca 4–59, Mg 0.3–3.5, K 0.1–3.0, Na 1.0–4.1 and Fe 0.4–4.5. Range in pH: 5.8–7.5. Despite the gradient in ion concentration, the element content in S. hirculus was constant along the transect. Population density reached maximum in the rich fen, 52 floral shoots 0.25 m −2 . In the spring area, S. hirculus was characterized by few flowers per floral shoot, low height, numerous runners and a large total length of runners. In the rich fen, high seed production was characteristic; in the intermediate fen, production of both runners and seeds were low. The flowering of S. hirculus starts early in the spring area. Consequences of this with regard to genetic variation along the transect are briefly discussed.