scholarly journals Nest-predator prevalence along a mountain birch - alpine tundra ecotone

2011 ◽  
Vol 38 (6) ◽  
pp. 525
Author(s):  
Åshild Ø. Pedersen ◽  
Lasse Asmyhr ◽  
Hans Christian Pedersen ◽  
Nina E. Eide
Keyword(s):  
Nest Predation ◽  
Alpine Tundra ◽  
Mountain Birch ◽  
Pine Marten ◽  
Willow Ptarmigan ◽  
Generalist Species ◽  
Management Actions ◽  
Nest Predator ◽  
Predation Rates ◽  
Birch Forests

Context Nest predation is a major factor influencing life history and population dynamics of ground-nesting birds. The transitions between the northern boreal mountain birch forests and the low-alpine tundra are important habitats for the willow ptarmigan, Lagopus lagopus (Linnaeus, 1758). During the past decades, these landscapes have been extensively developed with cabin resorts in southern Norway, which has led to an increased number of roads and foot paths in relatively undisturbed habitats. Aims The aim of the present study was to investigate relative nest-predation rates in elevation gradients (ecotones) spanning from northern boreal mountain birch forests to low-alpine tundra in three locations with contrasting willow ptarmigan densities. Methods We conducted an artificial nest study by using baited track boards (n = 108). Track boards were placed along transects (200 m) in the following three habitat types: birch forest, edge habitat and low-alpine tundra. Predator prevalence was analysed in relation to study-design variables (location, habitat, study period) and the load of human infrastructure (i.e. distance to foot paths and roads), using generalised linear mixed-effect models assuming binomial distribution for the response variable. Key results Prevalence of avian predators was consistently high (range 38.2–85.3%), in contrast to much lower prevalence of mammalian predators (range 2.8–22.9%). Raven (Corvus corax) was the dominant nest predator, followed by hooded crow (C. cornix) and pine marten (Martes martes). Location, as contrasted by differences in willow ptarmigan density, was not significantly related to total relative predation rates. Species-specific predator prevalence was habitat specific and related to human infrastructure, but with opposite relative predation patterns between pine marten and raven. Hooded crow predation was similar across the ecotone and not related to human infrastructure. Conclusions Predator prevalence was habitat specific and affected by human infrastructure (distance to human foot paths). Our study confirmed that human activity might alter the predation rates by generalist species in these low-alpine environments. Implications We recommend that attractive willow ptarmigan habitat should be avoided when planning human infrastructure in alpine ecosystems. To reduce predation pressure in this ecosystem, it appears that generalist predators should be considered for management actions. Further research is needed to explain the underlying mechanism driving expansion of generalist species into alpine habitats. Such knowledge is also important in developing alternative management actions with focus other than predator control.

Response to logging by a limited but variable nest predator guild in the boreal forest

2008 ◽  
Vol 38 (7) ◽  
pp. 1974-1982 ◽  
Author(s):  
Randy G. Thompson ◽  
Ian G. Warkentin ◽  
Stephen P. Flemming
Keyword(s):  
Boreal Forest ◽  
Nest Predation ◽  
Forest Cover ◽  
Landscape Fragmentation ◽  
Artificial Nests ◽  
Gray Jays ◽  
Predator Guild ◽  
Nest Predator ◽  
Predation Rates ◽  
Nest Predators

Predation rates on the eggs and young of forest-nesting songbirds typically rise in association with anthropogenic fragmentation, but predator responses depend on the spatial scale of disturbance, context, and predator assemblages present. For landscapes that are naturally fragmented, such as the boreal forest, our understanding of nest predation patterns associated with harvest may be further confounded by an additive response of nest predators to the loss of forest cover and the extension of habitat edges. We examined predation rates on artificial nests across a range of values for landscape metrics reflecting natural and anthropogenic forest fragmentation during two summers in boreal forest stands of western Newfoundland, Canada. Nest predation by gray jays ( Perisoreus canadensis (L.)) increased significantly in logged areas, and gray jay abundance was positively linked to increasing amounts of logged edge; however, there was no response to the extent of natural openings suggesting that nest predation by jays was additive in the presence of harvest-created openings. In contrast, neither mammalian nest predators nor the unidentified predators (responsible for the largest proportion of nest losses) showed any association with the landscape fragmentation metrics assessed. Year effects shown by the unidentified nest predator category did coincide with a marked increase in small mammal and Newfoundland marten ( Martes americana (Turton) subsp. atrata (Bangs)) populations during our study. Thus, we were able to identify an additive predation response to logging, but also that the activities of predators may vary over space and time and, in turn, may variably influence the success of songbirds nesting in forests fragmented by logging.

Spatial ecology of Western Ratsnakes (Pantherophis obsoletus) : implications for bird nest predation

2014 ◽  
Author(s):  
◽  
Andrew D. George
Keyword(s):  
Nest Predation ◽  
Resource Selection ◽  
Activity Patterns ◽  
Bird Species ◽  
Thermal Conditions ◽  
Weather Data ◽  
Near Surface ◽  
Bird Nest ◽  
Nest Predator ◽  
Predation Rates

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] In fragmented Midwestern forests, many birds face high rates of nest predation, to the point where this region may serve as a population sink for some species. That is, so many of their eggs and young are eaten by predators that these birds cannot produce enough offspring to replace themselves, rendering regions like central Missouri a drain on some bird populations. One important difference between fragmented and contiguous forests (e.g., the Ozarks of southern Missouri where birds seem to be doing better) is that for some bird species, western ratsnakes (Pantherophis obsoletus) are by far the most important nest predator in the fragmented forests. Nest predation rates have been indirectly linked to ratsnake activity patterns or habitat, and recent nest camera studies have directly attributed nest predation by ratsnakes to increased forest fragmentation and weather conditions that are likely favored by ratsnakes. We conducted a large-scale radio-telemetry study of ratsnakes to evaluate their activity patterns and resource selection in study sites where they have been identified as the predominant bird nest predator. First, we used local weather data to model seasonal ratsnake movements as they relate to bird nesting phenology and climate change. Next, we used spatio-temporal temperature models to investigate the thermal conditions available to snakes. We used remote temperature sensors and high-resolution spatial data to develop a dynamic temperature surface for our study area. Models predicted near-surface air temperatures with high accuracy during the winter and growing season, and permitted us to include thermal conditions in resource selection models. Finally, we used discrete choice models to evaluate and predict ratsnake resource selection. We found strong evidence that ratsnakes preferentially select forest-field edges and other habitats that provide structural heterogeneity. Our findings support the hypothesis that edge effects explain increased predation rates in Midwestern forest fragments.

scholarly journals Herbaceous Encroachment from Mountain Birch Forests to Alpine Tundra Plant Communities Through Above- and Belowground Competition

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 170 ◽  
Author(s):  
Xinyuan Tan ◽  
Hong He ◽  
Shengwei Zong ◽  
Miaomiao Wu ◽  
Kai Liu ◽  
...  
Keyword(s):  
Plant Communities ◽  
Belowground Biomass ◽  
Alpine Tundra ◽  
Herbaceous Plants ◽  
Changbai Mountains ◽  
Mountain Birch ◽  
Native Plant ◽  
Alpine Plant ◽  
Alpine Plant Communities ◽  
Birch Forests

Alpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.

scholarly journals Do Repugnant Scents Increase Survival of Ground Nests? A Test with Artificial and Natural Duck Nests

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière
Keyword(s):  
Human Hair ◽  
Nest Predation ◽  
Survival Rates ◽  
Olfactory Cues ◽  
Artificial Nests ◽  
Treatment Groups ◽  
Mammalian Predators ◽  
High Predation ◽  
Ground Nesting ◽  
Predation Rates

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.

Above ground biomass changes in the mountain birch forests and mountain heaths of Finnmarksvidda, northern Norway, in the period 1957–2006

2009 ◽  
Vol 257 (1) ◽  
pp. 244-257 ◽  
Author(s):  
H. Tømmervik ◽  
B. Johansen ◽  
J.Å. Riseth ◽  
S.R. Karlsen ◽  
B. Solberg ◽  
...  
Keyword(s):  
Mountain Birch ◽  
Above Ground Biomass ◽  
Northern Norway ◽  
Ground Biomass ◽  
Birch Forests

scholarly journals No evidence for disruption of global patterns of nest predation in shorebirds

2019 ◽  
Author(s):  
Martin Bulla ◽  
Jeroen Reneerkens ◽  
Emily L. Weiser ◽  
Aleksandr Sokolov ◽  
Audrey R. Taylor ◽  
...  
Keyword(s):  
Climate Change ◽  
Nest Predation ◽  
The Arctic ◽  
Statistical Support ◽  
Methodological Problems ◽  
Global Patterns ◽  
The 1950S ◽  
Predation Rates

AbstractKubelka et al. (Science, 9 November 2018, p. 680-683) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.

scholarly journals Changes in mountain birch forests and reindeer management: Comparing different knowledge systems in Sápmi, northern Fennoscandia

Polar Record ◽  
2019 ◽  
Vol 55 (6) ◽  
pp. 507-521 ◽  
Author(s):  
Bruce C. Forbes ◽  
Minna T. Turunen ◽  
Päivi Soppela ◽  
Sirpa Rasmus ◽  
Terhi Vuojala-Magga ◽  
...  
Keyword(s):  
Scientific Knowledge ◽  
Practical Knowledge ◽  
Knowledge Systems ◽  
Mountain Birch ◽  
Reindeer Husbandry ◽  
Social Ecological Systems ◽  
Northern Fennoscandia ◽  
Northern Areas ◽  
Birch Forests

AbstractMountain birch forests in the northern areas of Sápmi, the Saami homeland, serve as pastures for semi-domesticated reindeer. Recent reindeer management of the area has, to date, proceeded with little involvement of reindeer herders or their knowledge. To get more in-depth understanding of recent changes, we present together herders’ knowledge and scientific knowledge concerning the impacts of herbivory and climate change on mountain birch forests in three Saami communities in Norway and in Finland. Most of the herders interviewed reported changes in weather during the preceding decades. Herders agreed that the canopy and understorey of mountain birch forests have changed. The observed transformations in the quality of pastures have increased the financial costs of reindeer husbandry. Our study demonstrates that herders have practical knowledge of the present state and recent changes of birch forests, and of the responses of reindeer caused by these. This knowledge generally coincides with scientific knowledge. We call for better integration of knowledge systems and a better protocol for co-production of knowledge as it relates to more adaptive future reindeer management regimes. Such integration will facilitate understanding of cultural adaptation within rapidly changing social-ecological systems in which sustainable reindeer husbandry continues to be an important livelihood.

Sign in / Sign up

Export Citation Format

Share Document