Use of Riparian Buffer Strips as Movement Corridors by Forest Birds

Abstract

We conducted a 3‐year field experiment to measure the frequency of bird movements through riparian buffer strips before and after harvesting of adjacent forest. Our study was conducted in the boreal mixed wood forest of Alberta and was designed to determine empirically whether songbirds use riparian buffer strips of forest connecting forest reserves as corridors and if they move along these buffer strips more frequently than they cross adjacent clearcuts. We used mist nets to obtain an index of the frequency of bird movement in the forest, and we observed bird movements across adjacent clearcuts for comparison. We predicted that the frequency of movement would be greater (1) in buffer strips after harvesting of adjacent forest than before harvesting, (2) in buffer strips than across clearcuts and, (3) in buffer strips than at control sites (lakeshore forest with no adjacent clearcuts). After adjusting for year‐to‐year variation in abundance, we found that capture rates increased significantly from pre‐ to post‐harvest, but only for juveniles. Capture rates of adults decreased immediately after harvesting, probably because of the removal of an adjacent source of birds that previously moved through the lakeside forest. Movement rates of forest species in clearcuts were significantly lower than capture rates in the forest. The number of adults captured was positively correlated with the number of territories in the buffer strips, indicating that most birds captured were probably residents. The number of local territories was a poor predictor of juvenile captures, supporting the notion that juveniles were likely dispersing individuals. Our results indicate that buffer strips enhanced movements of juveniles (i.e., acted as corridors) and maintained movement rates of adults. Furthermore, there appeared to be a threshold distance between reserves below which birds may be less reluctant to fly across openings, making corridor use less important.

Riparian corridors enhance movement of a forest specialist bird in fragmented tropical forest

“…Gaps in forest cover may generally be perceived as inhospitable by forest birds (19,24,25), because they are more detectable by predators there (26). Other studies have suggested that forest birds avoid gaps over a certain threshold of size (19,27), but no previous corridor study has provided enough spatial resolution to assess cumulative gap crossing behavior at a landscape scale.…”

Environmental Services Provided from Riparian Forests in the Nordic Countries

“…These results indicate that streams may act as movement corridors for forest birds (Machtans et al 1996). The general value of corridors for dispersal has been questioned (Machtans et al 1996;Simberloff and Cox 1987;Gustafsson and Hansson 1987;Niemelä 2001;Ö ckinger and Smith 2008). Several factors may influence the general value of corridors.…”

LiDAR derived ecological integrity indicators for riparian zones: Application to the Houille river in Southern Belgium/Northern France

“…As ecotones located at the intersection of land and water, riparian zones are exceptionally rich in biodiversity (Naiman and Décamps, 1990;Naiman et al, 1993). They represent ecological corridors (Rodriguez-Iturbe et al, 2009) and provide a crucial habitat for terrestrial animals and for migrating birds (Hilty and Merenlender, 2004;Machtans et al, 1996;Skagen et al, 1998Skagen et al, , 2005. The width of a zone can range from a few metres to several kilometres.…”