scholarly journals Territory size decreases minimally with increasing food abundance in stream salmonids: Implications for population regulation

2017 ◽  
Vol 86 (6) ◽  
pp. 1308-1316 ◽  
Author(s):  
James W. A. Grant ◽  
Laura K. Weir ◽  
Stefán Ó. Steingrímsson
Keyword(s):  
Population Regulation ◽  
Food Abundance ◽  
Territory Size ◽  
Stream Salmonids

Female Choice in Middendorff's Grasshopper-Warbler (Locustella Ochotensis)

The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 694-700 ◽  
Author(s):  
Hisashi Nagata
Keyword(s):  
Mate Choice ◽  
Female Choice ◽  
Morphological Characteristics ◽  
Female Mate Choice ◽  
Food Abundance ◽  
Territory Size ◽  
Territory Quality ◽  
Female Mate ◽  
Nest Sites ◽  
Grasshopper Warbler

Abstract Morphological and territorial factors that influence female mate choice were examined in the monogamous Middendorff's Grasshopper-Warbler (Locustella ochotensis) on an islet near Fukuoka, Japan. I assumed that pairing date corresponded with female mate choice. Pairing date was correlated with both territory size and food abundance but was not correlated with selected morphological characteristics of males. Territorial quality was assumed to be correlated with territory size because preferable food resources and nest sites were distributed randomly. I conclude that female mate choice was influenced by territory quality rather than by the morphological characteristics of males.

OPTIMAL TERRITORY SIZE IN THE CONVICT CICHLID

Behaviour ◽  
1999 ◽  
Vol 136 (10-11) ◽  
pp. 1347-1363 ◽  
Author(s):  
James W.A. Grant ◽  
Jason Praw
Keyword(s):  
Growth Rate ◽  
Social Stress ◽  
Patch Size ◽  
Growth Efficiency ◽  
Food Abundance ◽  
Territory Size ◽  
Initial Increase ◽  
Archocentrus Nigrofasciatus ◽  
Convict Cichlids ◽  
Intermediate Size

AbstractModels of optimal territory size are usually tested only by demonstrating that territory size is inversely related to food abundance or intruder number. The most fundamental predictions of the models, however, have rarely been tested: i.e. the fitness of the defender is a function of territory size and the optimal territory is one of intermediate size. We tested these predictions by measuring the growth rate of large convict cichlids (Archocentrus nigrofasciatus, formerly Cichlasoma nigrofasciatum) while defending food patches against smaller intruders over a 10-day period. Food patches differed in area by more than two orders of magnitude. We manipulated food abundance so that it increased with patch size in a decelerating way. As assumed, the realized benefits of defence (weight of food eaten by the defender) and the costs of defence (chase rate and chase radius) both increased in a decelerating way with increasing patch area. As predicted, the growth rate of the defender first increased and then decreased with increasing patch size. The initial increase in defender growth rate with increasing patch size was related to an increase in food eaten, but the decrease in growth rate for fish defending the largest patches was related to the costs of defence. Fish defending large patches had a low growth efficiency, apparently because of the social stress caused by intruders in their territories. Taken together, these results support the assumptions and predictions of optimal territory size models.

Territorial Defense, Territory Size, and Population Regulation

2005 ◽  
Vol 166 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Andrés López‐Sepulcre ◽  
Hanna Kokko
Keyword(s):  
Population Regulation ◽  
Territory Size ◽  
Territorial Defense

scholarly journals Implications of territory size for the measurement and prediction of salmonid abundance in streams

1998 ◽  
Vol 55 (S1) ◽  
pp. 181-190 ◽  
Author(s):  
JWA Grant ◽  
S Ó Steingrímsson ◽  
E R Keeley ◽  
R A Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Point Of View ◽  
Food Abundance ◽  
Effective Density ◽  
Sampling Unit ◽  
Territory Size ◽  
Salmonid Fishes ◽  
Age Classes ◽  
Order Of Magnitude ◽  
Habitat Saturation

Information about territory size is useful for both the measurement and prediction of salmonid abundance. Percent habitat saturation (PHS), the percentage of the stream area occupied by the territories of salmonid fishes, is a better measure of abundance than population density because the former integrates the effects of (a) several age-classes or species in a stream, and (b) variation in growth rate or sampling date. "Effective density" or "effective PHS," calculated by weighting crude density (no.·m-2) or PHS by the number of organisms in the sampling unit, more accurately reflects density from the organism's point of view than does crude density or PHS. Effective density and PHS of Atlantic salmon (Salmo salar) in Catamaran Brook, New Brunswick, increased by 0.4 fish per m2 and 4%, respectively, for each order of magnitude decrease in the area of the sampling unit. Literature data suggested that territory size is inversely related to food abundance and can be used to predict changes in salmonid abundance that accompany changes in food abundance. The allometry of territory size was a better predictor of the decline in density of a cohort of Atlantic salmon in Catamaran Brook than the allometry of metabolic requirements.

Food abundance and territory size in juvenile coho salmon (Oncorhynchus kisutch)

1981 ◽  
Vol 59 (9) ◽  
pp. 1801-1809 ◽  
Author(s):  
Lawrence M. Dill ◽  
Ronald C. Ydenberg ◽  
Alex H. G. Fraser
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Food Abundance ◽  
Territory Size ◽  
Feeding Territory ◽  
Effect Of Food ◽  
Benthic Food ◽  
The Relationship ◽  
Potential Food ◽  
Behavioural Mechanism

Feeding territory size and potential food abundance were measured simultaneously in a field population of juvenile (40–50 mm) coho salmon. Territory size was inversely related to the density of benthic food on the territory, as predicted from an energy-based model of territoriality. The relationship between the abundance of drift food and territory size was in the predicted direction, but was not significant. Territories were also smaller where intruder pressure was higher, but intrusion rate and food abundance were not directly correlated. Therefore, the effect of food abundance on territory size was not caused indirectly by attraction of nonterritorial fish to areas where food was abundant. In the laboratory, the distance from which a resident coho attacked an approaching model intruder increased asymptotically with hunger. The fish therefore appear to possess an appropriate behavioural mechanism (tactic) to adjust territory size to local food abundance.

Coyote space use in relation to prey abundance

1991 ◽  
Vol 69 (6) ◽  
pp. 1516-1521 ◽  
Author(s):  
L. Scott Mills ◽  
Frederick F. Knowlton
Keyword(s):  
Home Range ◽  
Great Basin ◽  
Space Use ◽  
Mortality Rates ◽  
Food Abundance ◽  
Prey Abundance ◽  
Territory Size ◽  
Home Ranges ◽  
Prey Scarcity ◽  
The Impact

Food abundance is an important factor determining space use in many species, but its effect on carnivore home range and territory size has rarely been investigated. We explored the relationship between food abundance for the coyote (Canis latrans) and space use in two study areas in the northern Great Basin, where the primary prey, the black-tailed jackrabbit (Lepus californicus), fluctuates dramatically in abundance. At one site, home ranges and territories were significantly larger during a time of prey-scarcity than when prey was abundant. Coyotes on the second site had similar-size home ranges and territories at low and high prey abundance, but a higher proportion and probably a higher number of individuals were transients during the prey-scarcity period. We propose mortality rates of coyotes as an important factor mediating adjustments in space use to food abundance, and suggest two mechanisms by which mortality might interact with food abundance. Higher mortality rates may simply permit more rapid adjustment of home range size to changing food conditions. Alternatively, higher mortality may selectively eliminate transients, thus reducing the impact of intruders in limiting the size of the remaining territories.

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