# Explain why a woodland ecosystem with high biodiversity is likely to be more stable than a woodland ecosystem with low biodiversity, following the removal of a herbivore species.

> OCR A-Level Biology A (H420) — 6.5 Ecosystems · Explain · 4 marks

> Two separate woodland ecosystems exist in the same region. Woodland A contains 47 plant species, 23 herbivore species, 12 predator species and numerous decomposer species. Woodland B contains 6 plant species, 4 herbivore species, 3 predator species and few decomposer species. In both woodlands, a single herbivore species is completely removed due to a novel disease.

## Mark scheme (4 marks)

1. In the high-biodiversity woodland, other herbivore species can fulfil a similar ecological role to the removed species
2. Predator species in the high-biodiversity woodland have alternative prey available, so predator populations are maintained
3. Plant species in the high-biodiversity woodland are less likely to undergo unchecked population growth following removal of the herbivore
4. In the low-biodiversity woodland the food web is simpler, so the loss of one species causes greater disruption to energy flow / population sizes throughout the ecosystem

## Key terms

- [biodiversity](https://www.gradenine.co.uk/glossary/biodiversity)
- [herbivore](https://www.gradenine.co.uk/glossary/herbivore)
- [ecosystem](https://www.gradenine.co.uk/glossary/ecosystem)

## Related

- [Revision notes for OCR A-Level Biology A (H420)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-a-woodland-ecosystem-with-8d8251cd) · Published by Druglandscape Ltd.