Long-term decline in white-tailed deer browse supply: can lichens and litterfall act as alternative food sources that preclude density-dependent feedbacks

2005 ◽  
Vol 83 (8) ◽  
pp. 1087-1096 ◽  
Author(s):  
Jean-Pierre Tremblay ◽  
Isabel Thibault ◽  
Christian Dussault ◽  
Jean Huot ◽  
Steeve D Côté
Keyword(s):  
Abies Balsamea ◽  
Balsam Fir ◽  
Alternative Food ◽  
Food Sources ◽  
Mature Trees ◽  
Deer Population ◽  
Recruitment Failure ◽  
Anticosti Island ◽  
Alternative Food Sources ◽  
The Impact

Selective browsing by cervids has persistent impacts on forest ecosystems. On Anticosti Island, Quebec, Canada, introduced white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) have caused massive changes to the native boreal forest. Despite the apparent stability of the deer population over recent decades, we suspected that they were not at equilibrium with their browse supply and that further degradation of the habitat had occurred. A comparison of two browse surveys conducted 25 years apart showed a strong decline in browse availability. Although balsam fir (Abies balsamea (L.) P. Mill.) remained the most available browse species, it declined or disappeared from most stands (n = 13). Preferred deciduous species that were still available 25 years ago have almost disappeared. The continuous decline of the browse supply confirmed our hypothesis. This situation may be exacerbated by a subsidy from the winter litterfall, a significant and stable alternative food source. The abundance of litterfall from mature trees is independent of browsing over a long time period, which introduces a temporal uncoupling between the impact of deer browsing on balsam fir seedlings and the negative feedback from recruitment failure of mature balsam fir on the deer population. This means that the system is susceptible to being forced into an alternative regime.

Establishment of natural regeneration under severe browsing pressure from white-tailed deer after group seed-tree cutting with scarification on Anticosti Island

2009 ◽  
Vol 39 (3) ◽  
pp. 596-605 ◽  
Author(s):  
Julien Beguin ◽  
Marcel Prévost ◽  
David Pothier ◽  
Steeve D. Côté
Keyword(s):  
Negative Impact ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
White Birch ◽  
Conifer Species ◽  
Double Pass ◽  
Advance Regeneration ◽  
Anticosti Island ◽  
The Impact ◽  
Tree Group

The use of large clearcuts with protection of advance regeneration is inappropriate for regeneration of balsam fir ( Abies balsamea (L.) Mill.) under severe browsing from white-tailed deer ( Odocoileus virginianus (Zimmermann)). However, little is known about the effects of tree-retention methods along with scarification on the establishment of balsam fir in a context of severe herbivory. Consequently, we hypothesized that seed-tree-group cutting in conjunction with soil scarification creates favourable conditions for balsam fir regeneration. In 1998 and 1999 we set up three circular forest groups of different sizes (40, 60, and 80 m in diameter) surrounded by three different intensities of scarification (no treatment, single pass, double pass) in two balsam fir stands on Anticosti Island, Quebec, Canada. Moreover, we used a network of fenced and unfenced regeneration plots to evaluate the impact of white-tailed deer browsing. The results showed that up to 7 years after harvest, seed-tree-group cutting did not improve the establishment of conifer species. Scarification had a negative impact on the abundance of conifer species, whereas white birch ( Betula papyrifera Marshall) density was significantly higher in areas scarified twice than in unscarified areas. Overall, the development of palatable tree species appears unlikely at deer densities >20 individuals/km2.

scholarly journals Replacing Red Meat with Alternative Food Sources of Protein on Risk of Type 2 Diabetes - Modeling Dietary Changes in a Causal Framework

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1418-1418
Author(s):  
Daniel Ibsen ◽  
Marianne Jakobsen ◽  
Jytte Halkjær ◽  
Erik Parner ◽  
Kim Overvad
Keyword(s):  
Type 2 Diabetes ◽  
Whole Grains ◽  
Red Meat ◽  
Risk Difference ◽  
Alternative Food ◽  
Food Sources ◽  
Incident Type ◽  
Exposure Effect ◽  
Alternative Food Sources

Abstract Objectives We investigated whether decreasing the intake of red meat and simultaneously increasing the intake of alternative food sources of protein affects the risk of type 2 diabetes compared with no changes in the substituted foods. We also examined interaction with the age at which participants changed their diet. Methods We used the Danish Diet, Cancer and Health cohort including men and women, two measures of diet taken roughly 5 years apart using food frequency questionnaires and information on incident type 2 diabetes derived from the Danish National Diabetes Register (n = 39,349; aged 55 to 72 years at the second diet measure; n cases = 3759). The pseudo-observation method was used to estimate the average exposure effect of decreasing the intake of red meat (processed and unprocessed) while increasing the intake of either poultry, fish, cheese, eggs or whole grains compared with no changes in the substituted foods on the subsequent 10-year risk of development type 2 diabetes. Results In multivariable adjusted models, we found that replacing 1 serving/day (100 g) of red meat with 1 serving/day of eggs (50 g) (risk difference −2.4%, 95% confidence interval −3.7 to −1.1%) or whole grains (30 g) (−1.4%, −2.2 to −0.6%) was associated with a reduced risk of type 2 diabetes. No effects were observed for other replacements. In general, the lowest risk was observed for replacements at age 55 years compared with older ages (up to 70 years) for all replacements. Conclusions Replacing red meat with eggs or whole grains may reduce the risk of type 2 diabetes compared with no changes in the substituted foods. Changing red meat intake in midlife may be more beneficial than at older ages. Funding Sources Aarhus University.

Effects of fenitrothion on the arthropod food of tree-foraging forest songbirds

1990 ◽  
Vol 68 (11) ◽  
pp. 2235-2242 ◽  
Author(s):  
Rhonda L. Millikin
Keyword(s):  
Active Ingredient ◽  
Significant Relationship ◽  
Tree Species ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Betula Papyrifera ◽  
White Birch ◽  
Forest Songbirds ◽  
The Impact

The impact of fenitrothion on the arthropod food of songbirds was measured using white birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.) branch sample and drop trays. Following ground application of fenitrothion at 293 g active ingredient/ha, there was a significant decrease in the biomass of arthropods as determined using branch samples from both tree species, but not until 5 days after the application (29% reduction for balsam fir, 35% for white birch). Samples from drop trays indicated an immediate kill of arthropods not associated with the tree. Most remaining arthropods on treated balsam fir trees were dead. These dead arthropods would not be suitable food for birds that require movement to detect their prey. There was no significant relationship between amount of deposit (treated trees only) and the reduction of arthropods for either tree species.

Alternative food sources of native and non-native bivalves in a subtropical eutrophic lake

Hydrobiologia ◽  
2013 ◽  
Vol 735 (1) ◽  
pp. 263-276 ◽  
Author(s):  
Soledad Marroni ◽  
Carlos Iglesias ◽  
Néstor Mazzeo ◽  
Juan Clemente ◽  
Franco Teixeira de Mello ◽  
...  
Keyword(s):  
Eutrophic Lake ◽  
Alternative Food ◽  
Food Sources ◽  
Alternative Food Sources

Stochastic simulation of growth loss in thinned balsam fir stands defoliated by the spruce budworm in Newfoundland

1998 ◽  
Vol 28 (5) ◽  
pp. 703-710 ◽  
Author(s):  
Erhard John Dobesberger
Keyword(s):  
Stochastic Simulation ◽  
Larval Density ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Damage Function ◽  
Balsam Fir ◽  
Negative Exponential Function ◽  
Attack Pattern ◽  
Growth Loss ◽  
The Impact

A stochastic simulation model was developed to derive a damage function for the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), and balsam fir, Abies balsamea (L.) Mill., herbivore interaction at the stand level for open-grown trees. Both aggregated and uniform models of attack pattern by late-instar larvae based on k of the negative binomial were evaluated to determine the impact of larval density and attack pattern on the loss in stemwood volume increment of young, thinned balsam fir stands in Newfoundland. Percentage loss in stemwood increment was a nonlinear, negative exponential function of initial larval density. Implementation of control measures to prevent 50% defoliation that is caused by about 14 larvae/branch tip would result in saving 24% of the annual stemwood increment after 1 year of defoliation and about 32% after 2 years of cumulative defoliation. Aggregation of spruce budworm larvae among trees within a forest stand results in less growth loss compared with a uniform pattern of attack. The nonlinear damage function may suggest tolerance and possibly compensatory growth after herbivory by low population levels of the spruce budworm.

Winter habitat selection by white-tailed deer on Anticosti Island 2: relationship between deer density from an aerial survey and the proportion of balsam fir forest on vegetation maps

2004 ◽  
Vol 82 (4) ◽  
pp. 671-676 ◽  
Author(s):  
François Potvin ◽  
Barry Boots
Keyword(s):  
Habitat Management ◽  
Abies Balsamea ◽  
Window Size ◽  
Aerial Survey ◽  
Balsam Fir ◽  
Winter Habitat ◽  
Deer Density ◽  
Vegetation Maps ◽  
Anticosti Island ◽  
The Relationship

Determining at what scale to operate and how much cover is needed are important questions for winter habitat management of white-tailed deer, Odocoileus virginianus (Zimmermann, 1780), through logging. We used binary cover maps (reclassified forest vegetation maps) and windows of different sizes (0.2 km × 0.2 km, 0.5 km × 0.5 km, 1 km × 1 km, 2 km × 2 km, and 3 km × 3 km) to describe the relationship between deer density from an aerial survey and the proportion of balsam fir, Abies balsamea (L.) P. Mill., forest (BF) cover in a 270-km2 block on Anticosti Island, Quebec. Maximum white-tailed deer densities reached were quite similar (31–34 deer/km2) irrespective of window size, except for the 3 km × 3 km window for which maximum density remained half lower. Density increased with the amount of BF cover and then reached a plateau above 60% or 70% (two smaller windows) or decreased above 50% or 60% (1 km × 1 km and 2 km × 2 km windows). Results confirm goals previously used for habitat management of deeryards. This new method allows greater flexibility in research applications for describing density–cover relationships because both scale and proportion of cover can be analysed simultaneously.

Comparative responses of small mammals, vegetation, and food sources to natural regeneration and conifer release treatments in boreal balsam fir stands of Quebec

1999 ◽  
Vol 29 (7) ◽  
pp. 1128-1140 ◽  
Author(s):  
Nancy Gagné ◽  
Louis Bélanger ◽  
Jean Huot
Keyword(s):  
Small Mammals ◽  
Natural Regeneration ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Rubus Idaeus ◽  
Balsam Fir ◽  
Food Sources ◽  
Ground Vegetation ◽  
Growing Seasons ◽  
Advance Regeneration

Abundance and species diversity of small mammals were compared among three regeneration methods used in boreal balsam fir (Abies balsamea (L.) Mill.) forests. Those methods were natural regeneration after "careful logging" to retain advance regeneration and planting (black spruce, Picea mariana (Mill.) BSP) followed by herbicide (Vision®) release or brushsaw cutting release. Deciduous vegetation was reduced for two growing seasons in both plantation types after treatment, and foliar arthropods decreased for one growing season. In herbicide-treated plantations, red raspberry (Rubus idaeus L.) shrub cover, near-ground vegetation, and production of berries were reduced for two growing seasons. After herbicide release, the abundance of the red-backed vole (Clethrionomys gapperi (Vigors)) was significantly lowered for two growing seasons. This negative effect was associated with reduced cover during the first two post-treatment growing seasons. In the short term, herbicide-treated plantations constitute poorer red-backed vole habitats than brushsaw plantations. In early successional boreal balsam fir stands, planting did not markedly affect small mammals probably because natural regeneration was common in these plantations.

Sign in / Sign up

Export Citation Format

Share Document