Wildlife and Fisheries Habitat Management
What this domain tests
Habitat elements, seral stage diversity, snags and down wood, stream and riparian habitat, and trade-offs between timber harvest and species needs.
Core rules
- Habitat requires food, cover, water, and space arranged at the right scale. A stand with cover but no foraging area supports fewer animals than a mosaic.
- Seral stage diversity supports more species than any single stage. Early seral favors deer, elk, and many songbirds; late seral favors cavity users and interior species.
- Snags and coarse woody debris are habitat structures, not waste. Retain hard snags for cavities, soft snags for foraging, and down logs for cover and moisture.
- Edge is not automatically good; interior species lose habitat when a block is fragmented because nest predation and parasitism rise near edges.
- Riparian zones and large wood create pools, cover, and temperature refugia; removing wood simplifies channels and reduces salmonid rearing capacity.
- Habitat suitability models are screening tools, not population estimates.
Worked example
A 40-acre harvest unit needs 3 snags per acre larger than 15 inches DBH, or 120 snags. The pre-harvest cruise finds 0.8 snags per acre of that size, about 32 trees. The difference is 88 trees that must be retained or created, so the marking crew protects 88 existing candidates and may girdle additional trees to meet the density.
Traps
Treating old growth as the only valuable habitat; leaving only cull trees, which are often too small or too decayed; assuming more edge always means more wildlife; ignoring the difference between a snag and a live den tree.