Is Ammophila arenaria (Marram grass) a threat to South African dune fields?

Ammophila arenaria (marram grass) was introduced to South Africa from Europe as a means of stabilizing the Cape Flats in the 1870s, but was only successfully established in the 1890s as it was found that seeds from the first introductions did not readily germinate. By the end of the last century, it was successfully used as a dune stabilizing grass. It is now widely used in stabilization projects along the Cape coastline, being established by planting cuttings or whole plants. Because of problems experienced of marram becoming invasive, especially on the west coast of North America, and the fact that we have many invasive species which threaten our indigenous dune fields, studies have been initiated on this plant in South Africa. Most work to date has involved investigating the methods used to establish the plant in stabilization sites, and very little has been done on the biology of the species in this country. Marram is generally thought not to seed in South Africa, and thus its spread has been limited. However, in the light of recent reports of successful germination of the seed, detailed studies on the phenology of seed production and establishment in natural areas will be undertaken. Studies on the natural control by fungal species and nematodes will be carried out in conjunction with work done in the Netherlands, so that a comparison of the biology of the species in South Africa can be made with that in Europe, where it is used extensively to stabilize dunes.     

IsAmmophila arenaria (Marram grass) a threat to South African dune fields?

Ammophila arenaria (marram grass) was introduced to South Africa from Europe as a means of stabilizing the Cape Flats in the 1870s, but was only successfully established in the 1890s as it was found that seeds from the first introductions did not readily germinate. By the end of the last century, it was successfully used as a dune stabilizing grass. It is now widely used in stabilization projects along the Cape coastline, being established by planting cuttings or whole plants. Because of problems experienced of marram becoming invasive, especially on the west coast of North America, and the fact that we have many invasive species which threaten our indigenous dune fields, studies have been initiated on this plant in South Africa. Most work to date has involved investigating the methods used to establish the plant in stabilization sites, and very little has been done on the biology of the species in this country. Marram is generally thought not to seed in South Africa, and thus its spread has been limited. However, in the light of recent reports of successful germination of the seed, detailed studies on the phenology of seed production and establishment in natural areas will be undertaken. Studies on the natural control by fungal species and nematodes will be carried out in conjunction with work done in the Netherlands, so that a comparison of the biology of the species in South Africa can be made with that in Europe, where it is used extensively to stabilize dunes. Nomenclature: Arnold & de Wet (1993) for vascular plants.     

Microhabitat selection in the simple oribatid community dwelling in epilithic moss cover (Acari: Oribatida)

The moss cover of a roof was studied as the model of a simple habitat divided into microhabitats by the members of a community of saprophagous mites. This community consisted of two species of oribatid mites: Scutovertex minutus and Trichoribates trimaculatus. They were extracted from moss onto moist paper, and subsequently, their mobility, responses to moisture fluctuation, and food selection were tested in laboratory experiments. For the nutritional biology, the microanatomy of their alimentary tract was examined according to the system of histological characteristics formulated in the laboratory of the author (type of food, digestive activity of gut walls, etc.). The paraplast sections of the mites were stained by Masson triple stain for these purposes. Moreover, the enzymological tests (chitinase and cellulase activities) were performed to detail the digestive processes. Such an approach was applied to field-sampled specimens as well as to those in the laboratory experiments. These above-mentioned data were discussed with respect to microhabitat selection, vertical and horizontal distribution, and dispersal ability of these two oribatid mites sharing this habitat. These two species differ in several characteristics from each other and these differences resulted in their different microhabitat choices and role in the habitat as a whole.