Cf. Dormann et Jp. Bakker, The impact of herbivory and competition on flowering and survival during saltmarsh succession, PLANT BIO, 2(1), 2000, pp. 68-76
For succession, the establishment and turnover of plants, in terms of gener
ative spreading and renewal, is of crucial importance. Especially the succe
ss of seedling establishment into the existing vegetation might be of prime
importance for the further development of plant species composition. Flowe
ring, on the other hand, is the necessary first step towards generative out
put and later seed set. In a chronosequential gradient of a saltmarsh succe
ssion, we investigated the performance of transplants of three common speci
es under different conditions: Artemisia maritime, Atriplex portulacoides a
nd Plantago maritime were transplanted as seedlings and mature plants into
plots in early-, mid-, and late-successional stages (15, 30 and 40 years) o
n the Dutch island of Schiermonnikoog. Natural herbivory (by hares and gees
e) and neighbourhood competition were excluded in a factorial design. Flowe
ring and survival rates of the three species were generally greatly reduced
under natural conditions, compared to competition- and herbivory-free plot
s. The survival rates of Artemisia maritima and Plantago maritima reflect t
heir position as early-successional species: early in succession, both show
their highest survival and abundance. For late-dominant Atriplex portulaco
ides a different explanation has to be invoked for the medium-high survival
and low abundance: probably winter grazing by hares and the importance of
a high nitrogen supply rate, rather than flowering and survival, determine
its low abundance in the early and mid-phase of this saltmarsh succession.
Some long-term impacts of herbivores affecting flowering and survival are d
iscussed.