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Description
In this programme meadow, woodland, bog and agricultural ecosystems are examined and compared.
In this programme meadow, woodland, bog and agricultural ecosystems are examined and compared.
| Module code and title: | S323, Ecology |
|---|---|
| Item code: | S323; 01 |
| First transmission date: | 12-02-1974 |
| Published: | 1974 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:00 |
| + Show more... | |
| Producer: | Edward Milner |
| Contributor: | Irene Ridge |
| Publisher: | BBC Open University |
| Keyword(s): | Beetle larvae; Blook Moor, Derbyshire; Cow dung; Flora; Grassland ecosystem; Herbivores; Ladybird beetle; Post Meadow, Oxford; Recycling of nutrients; Trophic structure; Vaccinium myrtillus; Woodland; Wytham Wood, Berks. |
| Footage description: | Film shots of Post Meadow, Oxford, common land which has been grazed for over 1000 years without man management. Commentary by Irene Ridge. She examines the trophic structure of this grassland ecosystem beginning- with the primary producers (mainly grasses). Shots of herbivores (cattle) grazing on the meadows. Shots of other herbivores (horses, slugs and geese). Ridge explains their contribution to the ecosystem. Shots of beetle larvae and ladybird beetle, two primary carnivores of the third trophic level of the meadow ecosystem. Irene Ridge, on the meadow, discusses the recycling of nutrients by organisms which live off the dead plant material. She looks at several ways in which nutrients are returned to the meadow. Shots of river in flood (minerals are returned by the flood waters). Shots of cow dung. Ridge explains how this is broken down by bacteria and dung fly larva (detritivores). Irene Ridge in Wytham Wood, Berks. She describes the ecosystem of the woodland and compares it with the meadow ecosystem. She discusses the growth habits and structures of the plants living there. Ridge stops on her walk through the wood and examines some of the sparse ground flora. Ridge relates the quantity of ground flora to the low light levels on the woodland floor where a leaf ratio of 8 is not uncommon. To demonstrate, the camera acts as a lightmeter and pans across the wood. The picture becomes more and more dim. In places the leaf canopy has absorbed 95% of the incident light. Shots of leaf eating caterpillar and damaged leaves in the wood. Irene Ridge on Blook Moor, near Glossop, Derbyshire, an acid peat moor 1000 ft above sea level. She describes and points out the primary producers in this eco-system - Sphagnum mosses bilberry (Vaccinium myrtillus) and heather (Calluna Vulgaris). Shots of peat being dug and carried away. Ridge explains how the wet acid conditions prevent decomposers from working on the dead organic matter thus allowing peat to form. Shots of bog corpses which have been preserved in the acid peat bog (These are still shots of bog men excavated in Denmark). Shots of a wheatfield at the Oxford University farm. Ridge contrasts this man-managed monoculture with the three previous eco-systems. Ridge examines the resources which go into a wheatfield to maintain high productivity. She expresses these in cash terms and arrives at a figure of £28.90 per acre for seed, fertiliser, herbicides, tractor fuel and man-hours for cultivation in 1973. |
| Master spool number: | 6HT/71218 |
| Production number: | 00525_1122 |
| Videofinder number: | 1024 |
| Available to public: | no |
