scholarly journals Integrating plant stoichiometry and feeding experiments: state-dependent forage choice and its implications on body mass

2021 ◽  
Author(s):  
Juliana Balluffi-Fry ◽  
Shawn J. Leroux ◽  
Yolanda F. Wiersma ◽  
Isabella C. Richmond ◽  
Travis R. Heckford ◽  
...  
Keyword(s):  
Black Spruce ◽  
Snowshoe Hare ◽  
Home Ranges ◽  
Nitrogen And Phosphorus ◽  
Plant Resource ◽  
Feeding Experiments ◽  
Growing Conditions ◽  
Feeding Choices ◽  
Quality Variation ◽  
Trapping Grid

AbstractIntraspecific feeding choices account for a large portion of herbivore foraging in many ecosystems. Plant resource quality is heterogeneously distributed, affected by nutrient availability and growing conditions. Herbivores navigate landscapes, making feeding decisions according to food qualities, but also energetic and nutritional demands. We test three non-exclusive foraging hypotheses using the snowshoe hare (Lepus americanus): 1) herbivores feeding choices and body conditions respond to intraspecific plant quality variation, 2) feeding responses are mitigated when energetic demands are high, and 3) feeding responses are inflated when nutritional demands are high. We measured black spruce (Picea mariana) nitrogen, phosphorus, and terpene compositions, as indicators of quality, within a snowshoe hare trapping grid and found plant growing conditions to explain spruce quality variation (R2 < 0.36). We then offered two qualities of spruce (H1) from the trapping grid to hares in cafeteria-style experiments and measured their feeding and body condition responses (n = 75). We proxied energetic demands (H2) with ambient temperature and coat insulation (% white coat) and nutritional demands (H3) with the spruce quality (nitrogen and phosphorus content) in home ranges. Hares that preferred higher-quality spruce lost less weight during experiments (p = 0.018). The results supported our energetic predictions: hares in colder temperatures and with less-insulative coats (lower % white) consumed more spruce and were less selective towards high-quality spruce. Collectively, we found variation in plant growing conditions within herbivore home ranges substantial enough to affect herbivore body conditions, but any plant-herbivore interactions are also mediated by animal energetic states.

Behavioural responses of lynx to declining snowshoe hare abundance

1985 ◽  
Vol 63 (12) ◽  
pp. 2817-2824 ◽  
Author(s):  
Richard M. P. Ward ◽  
Charles J. Krebs
Keyword(s):  
Home Range Size ◽  
High Rate ◽  
Snowshoe Hare ◽  
Home Ranges ◽  
Lynx Lynx ◽  
Lynx Canadensis ◽  
Long Distance ◽  
Behavioural Responses ◽  
Straight Line ◽  
Daily Travel

The behavioural responses of lynx (Lynx canadensis) to declines in snowshoe hare (Lepus americanus) abundance were examined in the southwestern Yukon. Between April 1982 and June 1984, 11 lynx were radio tagged and monitored in and near the Kluane Game Sanctuary. Lynx home range size increased from 13.2 to 39.2 km2 concurrent with a decline in snowshoe hare abundance from 14.7 to 0.2 hares/ha. Below about 0.5 hares/ha, several lynx abandoned their home ranges and became nomadic, although they remained within the general study area. Lynx concentrated their foraging efforts in areas of relatively high snowshoe hare abundance and abandoned these areas after hares declined. Straight-line daily travel distance remained constant at 2.2−2.7 km/day above 1.0 hare/ha. Below 1.0 hares/ha, straight-line daily travel distances increased rapidly, reaching 5.5 km/day at 0.2 hares/ha. Three of seven radio-tagged lynx dispersed 250 km or more from the study area during the 1982 period of rapid hare decline. No similar long-distance emigrations were recorded after hare densities stabilized at less than 1.0 hares/ha. Trapping mortality was responsible for the loss of seven of nine radio-tagged lynx that travelled outside the game sanctuary. One lynx probably starved during the winter or spring of 1984. The high rate of trapping mortality outside the game sanctuary suggests that refugia in wilderness areas are important in maintaining lynx populations during periods of low recruitment.

Recovery time of snowshoe hare habitat after commercial thinning in boreal Quebec

2012 ◽  
Vol 42 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Guylaine Bois ◽  
Louis Imbeau ◽  
Marc J. Mazerolle
Keyword(s):  
Habitat Use ◽  
Black Spruce ◽  
Keystone Species ◽  
Snowshoe Hare ◽  
Negative Effects ◽  
Boreal Ecosystems ◽  
Commercial Thinning ◽  
Long Term Impact ◽  
Habitat Parameters

As short-term effects of partial cuts generally decrease available cover for snowshoe hare ( Lepus americanus Erxleben), most studies have shown negative effects of such treatments on this keystone species in boreal ecosystems. This study aims to determine the long-term impact of commercial thinning on snowshoe hare habitat, and we hypothesized that habitat quality, as well as habitat use, recovers with time since treatment. We selected stands aged 50–90 years dominated by black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) in Abitibi (Quebec). We used models of habitat parameters to explain the abundance of snowshoe hare tracks and pellets in 20 commercially thinned stands treated between 1989 and 1999 and 12 control stands. Lateral cover was the dominant parameter influencing snowshoe hare habitat use. On average, commercially thinned stands had a lower lateral cover than controls (–18%). We also found that snowshoe hare use of commercially thinned stands increases with time since treatment. However, 11–18 years are needed before commercially thinned stands return to the same level of lateral cover and snowshoe hare signs as control stands. Commercial thinning is generally followed by harvesting all merchantable stems 15 years after treatment. Thus, we suggest that commercial thinning as currently practiced should be avoided if the objective is to maintain quality habitat for snowshoe hare and its associated predators.

scholarly journals Strip Thinning and Spacing Increases Tree Growth of Young Black Spruce

1996 ◽  
Vol 13 (2) ◽  
pp. 68-72 ◽  
Author(s):  
Joanie Burns ◽  
Klaus J. Puettmann ◽  
Don Perala
Keyword(s):  
Tree Growth ◽  
Growth Response ◽  
Black Spruce ◽  
Economic Feasibility ◽  
Stand Volume ◽  
Spruce Stands ◽  
Growing Conditions ◽  
Increased Growth Response

Abstract Two different thinning methods were applied to three 6- or 7-yr-old black spruce stands in northern Minnesota which were measured after 20 yr. Overall, thinning improved the growing conditions for crop trees. Strip thinning with a 0.6 m leave strip and three widths of cleared strips (1.5 m, 2.1 m, and 2.7 m), and spacing to 1.5 m, 2.1 m, and 2.7 m resulted in reduced numbers of crop trees, but with larger diameters and, in the spacing thinned plots, greater heights. Because of these contradicting trends, stand volume was unaffected by thinning. Crop tree growth was not affected by the width of the cleared strip, but the distances between the leave trees in the square spacing were positively related to the increased growth response after thinning. The study is still too young to evaluate the economic feasibility of both thinning treatments, but shorter rotations or substantially increased volume seem possible by early thinnings of black spruce. North. J. Appl. For. 13(2):68-72.

Nitrogen and phosphorus nutrition and nutrient cycling by evergreen and deciduous understory shrubs in an Alaskan black spruce forest

1983 ◽  
Vol 13 (5) ◽  
pp. 773-781 ◽  
Author(s):  
F. Stuart Chapin III
Keyword(s):  
Nutrient Cycling ◽  
Aboveground Biomass ◽  
Black Spruce ◽  
Leaf Biomass ◽  
Nitrogen And Phosphorus ◽  
Plant Parts ◽  
P Concentration ◽  
Aboveground Production ◽  
Understory Shrubs ◽  
Leaf N

Seasonal patterns of biomass, nitrogen (N), and phosphorus (P) were determined for major plant parts of the deciduous shrub Vacciniumuliginosum L. and the evergreen shrub Ledumgroenlandicum Oeder. in a black spruce (Piceamariana (Mill.) B.S.P.) forest in interior Alaska. New growth comprised 52 ± 7% of aboveground biomass in Vaccinium compared with the evergreen Ledum for which a maximum of 38 ± 3% of aboveground biomass was new growth. In Vaccinium the spring decline in leaf N and P concentration was due to dilution by increasing leaf biomass, whereas the autumn decline in N and P concentration was due to retranslocation, at which time 68–72% of leaf N and P was retranslocated from leaves. In contrast, the entire decline in N and P concentration of new growth in Ledum was due to dilution by increasing leaf biomass. Uptake contributed 60–68% of the maximum N and P requirement for aboveground growth of Vaccinium, with the remainder coming from stored reserves. Ledum supported 71–79% of its aboveground nutrient requirement by direct uptake from soil and may have been less dependent upon stored nutrient reserves. Vaccinium and Ledum together comprised only 0.8–2.8% of the standing crop of aboveground vascular biomass and N and P pools at Washington Creek but contributed 16% of vascular aboveground production and 19–24% of the N and P cycled annually by vascular plants. The importance of understory shrubs is due to their small support structure and rapid turnover of biomass and nutrients (34–43% of aboveground pools annually) relative to that of the trees (2–5% annually). Understory shrubs at Washington Creek and in other evergreen forests are much more important in nutrient cycling than their small biomass would suggest.

scholarly journals Influence of Different Factors on Productivity of Reed Growths

2015 ◽  
Vol 1 ◽  
pp. 106
Author(s):  
Edgars Čubars ◽  
Gotfrīds Noviks
Keyword(s):  
Water Body ◽  
Total Concentration ◽  
Regression Equation ◽  
Water Bodies ◽  
Winter Period ◽  
Nitrogen And Phosphorus ◽  
Factors Influencing ◽  
Artificial Water Bodies ◽  
Growing Conditions ◽  
Artificial Water

The study shows results of research on reed productivity and on factors influencing this productivity. The research was performed during winter period from 2010 until 2012 in 23 natural and artificial water bodies of Latvia. The author of this study analyzed indexes of reed growth productivity and found regularities that statistically significantly (p less then 0,05) explain changes of reed productivity in water bodies depending on individual reed growing conditions in each water body. It is established that the productivity of reed growth depends on the amount of nutrients in the water of water body and that this productivity rises if the total concentration of nitrogen and phosphorus in the water is increased. The reed productivity is lower in clearer water. This parameter may be used in order to evaluate the amount of extractable biomass. The coherence is characterized by statistically significant (p less then 0,05) regression equation.

Midwinter aggregation in the northern red-backed vole, Clethrionomys rutilus

1977 ◽  
Vol 55 (9) ◽  
pp. 1404-1409 ◽  
Author(s):  
Stephen D. West
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Early Spring ◽  
Dispersion Pattern ◽  
Short Supply ◽  
Advantages And Disadvantages ◽  
Composition And Structure ◽  
Moss Layer ◽  
Clethrionomys Rutilus ◽  
Trapping Grid

Livetrapping in black spruce (Picea mariana) taiga 60 km north of Fairbanks, Alaska, during 1972–1973 revealed that the dispersion pattern of the capture points for a population of northern red-backed voles varied greatly with season. The population was distributed without apparent aggregation from midsummer (July) until early winter (mid-November). During midwinter all animals were found in one section of the trapping grid. In early spring (April) the voles moved apart, and by May they appeared once more evenly distributed. The composition and structure of vegetation inside and outside of the area of aggregation was analyzed, and a significantly thicker moss layer was found within the area of aggregation. Possible advantages and disadvantages of the midwinter aggregation to individual voles are discussed. It is suggested that habitat limitation in terms of a short supply of suitable overwintering sites is a reasonable explanation for the observed aggregation.

scholarly journals Development of Black Spruce Layers in Quebec and Ontario

1968 ◽  
Vol 44 (2) ◽  
pp. 25-28 ◽  
Author(s):  
W. Stanek
Keyword(s):  
Black Spruce ◽  
Mineral Soil ◽  
Stem Form ◽  
Spruce Stands ◽  
Long Time ◽  
Seed Origin ◽  
Growing Conditions ◽  
Similar Growth

Black spruces of layer or seed origin develop into merchantable trees with similar growth in height, diameter and volume. Layerings tend to have a poorer stem form than seedlings, especially under adverse growing conditions. However, stem form of old layering trees is considerably better. The proportion of layerings and seedlings is influenced by stand history. Black spruce stands undisturbed for a long time consist largely of layerings. After fire, scarification, or exposure of mineral soil, stands regenerate mainly from seedlings. Stocking of black spruce is satisfactory where advance growth has been preserved after cutting, whether it is of layer or of seed origin.

scholarly journals Seasonal Nutrient Cycling and Enrichment of Nutrient-Related Soil Microbes Aid in the Adaptation of Ramie (Boehmeria nivea L.) to Nutrient-Deficient Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Shenglan Wu ◽  
Shuai Xue ◽  
Yasir Iqbal ◽  
Hucheng Xing ◽  
Yucheng Jie
Keyword(s):  
Nutrient Cycling ◽  
Illumina Miseq ◽  
Field Trials ◽  
Soil Conditions ◽  
Nitrogen And Phosphorus ◽  
Adverse Conditions ◽  
Boehmeria Nivea ◽  
Lack Of Information ◽  
Growing Conditions ◽  
Poor Soil

The breeding for varieties tolerant of adverse growing conditions is critical for sustainable agriculture, especially for ramie (Boehmeria nivea L.). However, a lack of information on the tolerance of ramie to nutrient-deficient conditions has hindered efforts to breed ramie varieties tolerant of such conditions. The main objective of this study was to explore the tolerance strategies of ramie plants under poor soil conditions using long-term (8–9 years) field trials. Genotypes of Duobeiti 1 and Xiangzhu XB were highly tolerant of poor soil conditions. The contributions of seasonal nutrient cycling and rhizobacteria to the ability of ramie to tolerate poor soil were tested. Nitrogen and phosphorus retranslocation to the root at the end of the growing season helped ramie adapt to poor soil conditions. The contribution of the microbial community was analyzed using high-throughput Illumina MiSeq sequencing technology. The enrichment of beneficial bacteria (mainly Bradyrhizobium, Gaiella, and norank_o_Gaiellales) and the reduction of harmful fungi (mainly Cladosporium and Aspergillus) also contributed to the ability of ramie to tolerate poor soils. The results of this study provide new insight into the ability of ramie to tolerate adverse conditions and aid future efforts to breed and cultivate ramie tolerant of adverse conditions.

The ecology of the lynx (Lynx canadensis) on Cape Breton Island

1983 ◽  
Vol 61 (4) ◽  
pp. 770-786 ◽  
Author(s):  
G. R. Parker ◽  
J. W. Maxwell ◽  
L. D. Morton ◽  
G. E. J. Smith
Keyword(s):  
Limited Range ◽  
Forest Harvesting ◽  
Snowshoe Hare ◽  
Home Ranges ◽  
Lynx Lynx ◽  
Lynx Canadensis ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Hunting Success ◽  
Main Component

Recruitment of lynx (Lynx canadensis) on Cape Breton Island declined from 1977–1978 through 1979–1980 concurrent with a decrease in snowshoe hare (Lepus americanus) densities. Suppressed recruitment resulted from a decline in pregnancy rates, especially in the yearling cohort, and increased mortality of kits during the first 6 months of life. Snowshoe hare was the main component in the diet of lynx during both winter and summer. Lynx rarely travelled together except for females with kits. Hunting success (percent successful chases) increased wth group size. Overall hunting success increased through the winter. Winter kill rates averaged one hare per lynx per 24 h. Home ranges of adults were larger in summer (25–32 km2) than in winter (12–18 km2). Daily cruising distances (kilometres per 24 h) were greater in summer (~9 km) than in winter (~8 km). Although lynx used all habitats within their home ranges, they selected for the advanced successional habitat (~20 years after cutting) both winter and summer. Mature conifer habitat was used more in summer than in winter. The short-term impact of extensive forest harvesting within the limited range of lynx on the highlands of Cape Breton Island is uncertain; in the long-term it should prove beneficial by increasing the availability of preferred advanced successional habitat. Harvesting of lynx should be closely controlled, especially during periods of reduced densities of snowshoe hares and suppressed recruitment of lynx.

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