Present address: Linda E. Green, Georgia Institute of Technology, School of Biology, 310 Ferst Drive, Atlanta, GA 30332-0230, U.S.A.
Salamander occupancy in headwater stream networks
Article first published online: 12 MAR 2009
Published 2009. This article is a US Government work and is in the public domain in the U.S.A.
Volume 54, Issue 6, pages 1370–1378, June 2009
How to Cite
GRANT, E. H. C., GREEN, L. E. and LOWE, W. H. (2009), Salamander occupancy in headwater stream networks. Freshwater Biology, 54: 1370–1378. doi: 10.1111/j.1365-2427.2009.02166.x
- Issue published online: 8 MAY 2009
- Article first published online: 12 MAR 2009
- (Manuscript accepted 22 December 2008)
- dendritic ecological network;
- headwater stream;
- protected areas;
- stream salamander
1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches.
2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders.
3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information–theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history.
4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region.
5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.