Spatially segregated foraging patterns of moose (Alces alces) and mountain hare (Lepus timidus) in a subarctic landscape: different tables in the same restaurant?

2015 ◽  
Vol 93 (5) ◽  
pp. 391-396 ◽  
Author(s):  
Sara M. Öhmark ◽  
Glenn R. Iason ◽  
R. Thomas Palo
Keyword(s):  
Environmental Heterogeneity ◽  
Plant Density ◽  
Unit Area ◽  
Alces Alces ◽  
Niche Separation ◽  
Mountain Hare ◽  
Foraging Patterns ◽  
Lepus Timidus ◽  
Body Sizes ◽  
Moose Browsing

Differences in body sizes of mountain hares (Lepus timidus L., 1758) and moose (Alces alces (L., 1758)) affect their ability to perceive and respond to environmental heterogeneity and plant density. Therefore, we expect these species to show niche separation at different scales in the same environment. Results showed that the numbers of mountain birches (Betula pubescens subsp. czerepanovii L.) browsed by moose per unit area was inversely related to hare browsing. Moose browsed larger birches compared with hares, and while hares targeted areas with high birch densities regardless of tree sizes, moose preferentially browsed areas with high densities of large birches. Moose browsing was clustered at spatial intervals of 1000–1500 m, while hare browsing was clustered at intervals of less than 500 m. Willows (genus Salix L.) in the study area were heavily browsed by moose, while few observations of hare browsing on willow were made. Regarding both hare and moose, numbers of birch stems with new browsing per sample plot were positively correlated with the numbers of birch stems with old browsing, indicating that hare and moose preferred the same foraging sites from year to year. These findings have implications for management of the species because they show the importance of scale and landscape perspectives in planning and actions.

The relationship between crop yield (or mean plant weight) of lettuce and plant density, length of growing period, and initial plant weight

1976 ◽  
Vol 86 (1) ◽  
pp. 83-91 ◽  
Author(s):  
M. A. Scaife ◽  
D. Jones
Keyword(s):  
Time Course ◽  
Plant Density ◽  
Unit Area ◽  
Subterranean Clover ◽  
Plant Weight ◽  
Relative Growth ◽  
Growing Period ◽  
Lettuce Growth ◽  
Log Linear ◽  
The Relationship

SUMMARYLettuce obeys the Shinozaki–Kira relationship in which the reciprocal of plant weight is linearly related to plant density. The intercept (a) represents the reciprocal of the weight of an isolated plant and the slope (b) represents the reciprocal of yield/unit area at high densities (the ‘ceiling yield’). This work examines the time course of (a) and (b) in an ‘ideal environment’ in which water and nutrients are non-limiting, and the light/temperature regime is constant.Two pot experiments are described: the first showed that the growth of isolated lettuces follows a logistic expression, which can therefore be substituted for a–1 in the Shinozaki-Kira equation. It was then hypothesized that b–1, the ‘ceiling yield’ would be constant over time. This was confirmed by the second experiment, giving the equationw–1t = w–10 e1–kt × w–1max × bd,in which wt is mean plant weight at time t, w0 and wmax are the initial and final weights of isolated plants, k is the early relative growth rate of such plants, b–1 is the constant ceiling yield, and d is the plant density.Two examples of the use of the equation are given: one shows how it predicts the interaction between seed size and plant density within a species (subterranean clover): the other illustrates how it can be used to explain why lettuce growth appears to be log-linear against time whereas cereal growth is more nearly just linear.

scholarly journals The seasonal trade-off between food and cover in the Alpine mountain hare (Lepus timidus)

2015 ◽  
Vol 62 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Maik Rehnus ◽  
Veronika Braunisch ◽  
Klaus Hackländer ◽  
Lea Jost ◽  
Kurt Bollmann
Keyword(s):  
Mountain Hare ◽  
Lepus Timidus ◽  
Trade Off

scholarly journals Migratory lineages rapidly evolve larger body sizes than non-migratory relatives in ray-finned fishes

2020 ◽  
Vol 287 (1918) ◽  
pp. 20192615 ◽  
Author(s):  
Michael D. Burns ◽  
Devin D. Bloom
Keyword(s):  
Body Size ◽  
Life History Theory ◽  
Environmental Heterogeneity ◽  
Empirical Studies ◽  
Adaptive Landscape ◽  
Migratory Species ◽  
Size Evolution ◽  
Body Sizes ◽  
Body Size Evolution ◽  
First Time

Migratory animals respond to environmental heterogeneity by predictably moving long distances in their lifetime. Migration has evolved repeatedly in animals, and many adaptations are found across the tree of life that increase migration efficiency. Life-history theory predicts that migratory species should evolve a larger body size than non-migratory species, and some empirical studies have shown this pattern. A recent study analysed the evolution of body size between diadromous and non-diadromous shads, herrings, anchovies and allies, finding that species evolved larger body sizes when adapting to a diadromous lifestyle. It remains unknown whether different fish clades adapt to migration similarly. We used an adaptive landscape framework to explore body size evolution for over 4500 migratory and non-migratory species of ray-finned fishes. By fitting models of macroevolution, we show that migratory species are evolving towards a body size that is larger than non-migratory species. Furthermore, we find that migratory lineages evolve towards their optimal body size more rapidly than non-migratory lineages, indicating body size is a key adaption for migratory fishes. Our results show, for the first time, that the largest vertebrate radiation on the planet exhibited strong evolutionary determinism when adapting to a migratory lifestyle.

scholarly journals Habitat selection and activity patterns in Alpine mountain hare (Lepus timidus varronis)

2013 ◽  
Vol 78 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Francesco Bisi ◽  
Mosé Nodari ◽  
Nuno Miguel Dos Santos Oliveira ◽  
Federico Ossi ◽  
Elisa Masseroni ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Activity Patterns ◽  
Mountain Hare ◽  
Lepus Timidus

The effect of plant density on populations of the cabbage root fly (Erioischia brassicae (Bch.)) and the cabbage stem weevil (Ceutorhynchus quadridens (Panz.)) on cauliflowers

1976 ◽  
Vol 66 (1) ◽  
pp. 113-123 ◽  
Author(s):  
S. Finch ◽  
G. Skinner
Keyword(s):  
Plant Density ◽  
Unit Area ◽  
Individual Plant ◽  
Cabbage Root Fly ◽  
Plant Densities ◽  
Equivalent Area ◽  
Concentric Circles ◽  
The Absolute ◽  
Absolute Population

AbstractTo study the effects of plant density on populations of the cabbage root fly (Erioischia brassicae (Bch.) ) and the cabbage stem weevil (Ceutorhynchus quadridens (Panz.)), cauliflowers were planted in 24 concentric circles to achieve spacings of 10–90 cm at 22 plant densities (1·5–83/m2). Some plants were treated with a root drench of chlorfenvinphos. Each week female cabbage root flies laid approximately three times as many eggs per individual plant at the lowest than at the highest plant densities tested. This was equivalent to approximately 350 and 5000 eggs/m2, respectively. The numbers of cabbage root fly pupae produced ranged from 11/m2 at the lowest to 210/m2 at the highest plant density. In the absence of an insecticide, increasing the plant density considerably increased the absolute population of the pest without affecting cauliflower yield. Approximately seven times as many flies were produced per unit area of untreated mini-cauliflowers as from an equivalent area of plants growing at a conventional density. When chlorfenvinphos was not applied, damage by the cabbage stem weevil occurred in 30% and 70% of the plants grown at the lowest and highest densities, respectively.

Mountain hare, Lepus timidus, bags and moor management

2009 ◽  
Vol 204 (4) ◽  
pp. 563-565 ◽  
Author(s):  
D. M. Stoddart ◽  
Raymond Hewson
Keyword(s):  
Mountain Hare ◽  
Lepus Timidus
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