Response to Bonsall & Hassell `Identifying Density-Dependent Processes: A Comment on the Regulation of Winter Moth'

10.2307/5859 ◽  
1995 ◽  
Vol 64 (6) ◽  
pp. 785
Author(s):  
Jens Roland
Keyword(s):  
Density Dependent ◽  
Winter Moth ◽  
Dependent Processes

Multiple density-dependent processes shape the dynamics of a spatially structured amphibian population

2018 ◽  
Vol 88 (1) ◽  
pp. 164-177 ◽  
Author(s):  
Hugo Cayuela ◽  
Benedikt R. Schmidt ◽  
Avril Weinbach ◽  
Aurélien Besnard ◽  
Pierre Joly
Keyword(s):  
Amphibian Population ◽  
Density Dependent ◽  
Dependent Processes

Density-dependent regulation of the growth of the hookworms Necator americanus and Ancylostoma ceylanicum

Parasitology ◽  
1994 ◽  
Vol 109 (1) ◽  
pp. 119-128 ◽  
Author(s):  
S. M. B. Norozian-Amiri ◽  
J. M. Behnke
Keyword(s):  
Worm Burden ◽  
Infection Intensity ◽  
Dry Weight ◽  
Ancylostoma Ceylanicum ◽  
Density Dependent ◽  
Necator Americanus ◽  
Infective Larvae ◽  
Length Width ◽  
Negative Relationships ◽  
Dependent Processes

SUMMARYLaboratory bred DSN hamsters were exposed to varying doses of infective larvae of Ancylostoma ceylanicum (orally) or Necator americanus (percutaneously) and were autopsied at times which corresponded to a period immediately before cessation of growth of worms or soon afterwards. A total of 829 (404 male and 425 female) A. ceylanicum and 1582 (781 male and 801 female) N. americanus were measured. At worm burdens of fewer than 100, the length of A. ceylanicum appeared to increase with infection intensity and no evidence was found that growth was retarded under crowded conditions. In an experiment comparing directly low (mean worm burden = 22) and heavy infections (mean worm burden = 180) significant negative associations between both weight and width, and worm burden were detected, but length again increased with worm burden. In contrast, 5 experiments with N. americanus indicated negative relationships between measures of worm size (length, width, wet and dry weight) and worm burden. It was concluded that N. americanus is subject to regulation by density-dependent processes within the host while A. ceylanicum is not sensitive to the same degree.

Estimating the Density and Mortality of Juvenile Western Rock Lobsters (Panulirus cygnus) in Nursery Reefs

1990 ◽  
Vol 47 (7) ◽  
pp. 1330-1338 ◽  
Author(s):  
Bruce F. Phillips
Keyword(s):  
Frequency Analysis ◽  
Larval Settlement ◽  
Alternative Methods ◽  
Length Frequency ◽  
Density Dependent ◽  
Additional Information ◽  
Single Night ◽  
Panulirus Cygnus ◽  
Dependent Processes ◽  
Length Frequency Analysis

Studies of juvenile rock lobsters (Panulirus cygnus) in the nursery reefs of Western Australia indicated that density-dependent processes on the reefs were the major determinant of year-class strengths of recruitment to the fishery. Reassessment of early data, plus additional information, indicates that these estimates may have been inaccurate. Alternative methods of estimating juvenile densities were examined; application of length–frequency analysis to calculate the age-classes; visual estimates, and single-night trapping. Length–frequency analysis indicated that either immigration onto the test reefs had occurred, or the data were inaccurate. Visual estimates and single-night trapping were more rapid and used less manpower and resources than mark–recapture methods, but the estimates were of unknown accuracy. No truly satisfactory method of making reliable estimates of either the density of natural mortality rate of juveniles in the nursery reefs is yet available. Nevertheless, the data on the levels of larval settlement and subsequent catches, suggest that density dependent processes probably have a significant effect on the levels of recruitment to the fishery, although the upper level to this recruitment has not been reached over the past 20 yrs.

Sign in / Sign up

Export Citation Format

Share Document