This article looked at a study analyzing the effects on birds, around raillines, motorways, rivers and bridges. This is quite a significant study as it will determine some facts in the movements of birds around these areas. Camley Street nature reserve has a strong link with birds and is surrouded by some of these features, including rail, river and road.
Some of the findings were quite significant.
- "In areas with vegetation gaps of 45 meters, birds were half as likely to cross as they were in uninterrupted forest cover. It may be that songbirds fear predation by raptors, and so they avoid gaps in vegetation.
- Traffic volume was a negative factor for bird crossing, though less important than vegetation gap. This is consistent with other studies, which have found that traffic volume has a greater effect on the crossing of large mammals while vegetation gap is more important for smaller species such as birds.
- Railways and light transit lines were the most permeable features to bird crossing. The researchers suspect that this is likely due to their relatively narrow width and low traffic volume.
- Surprisingly, rivers were the least permeable to bird crossing. The researchers speculate that rivers may serve as natural territorial boundaries that birds are reluctant to cross.
Not so surprising, birds were much more likely to cross over bridges than under them even when it was less direct". http://www.conservationmaven.com/frontpage/2009/11/10/the-permeability-of-the-urban-landscape-to-wildlife-movement.html
http://www.cartoonstock.com/lowres/mba0796l.jpg
No comments:
Post a Comment