ENERGETICS AND ANIMAL PllODUCTIVITY
93
comprehensive framework, comparing different communities (pages 8,
9) as well as components within the communities. He used data from
several authors in the compilation of this table. The table contained
data from both forest (coniferous and deciduous) and grassland communities.
In Table VII are listed the percentage of animals comprising each
major trophic group as given by Macfadyen and the rank each group
held with equivalent trophic groups of the other communities. I have
used these data to compute a rough carnivore-herbivore ratio and
several generalizations emerge: (1) There is a rather constant percentage
(20 to 33%) of herbivores - this category includes anima@ which reside
in the soil and feed upon algae and roots of’ green plants but not upon
bacteria and fungi. (2) There is an inverse relationship between the percentages of predators and large decomposerig (sig. at the 5% level using
Spearman rank correlation (Siegel, 1956, page 202) ). (3) It would appear
that there is an inverse relationship between the percentages of large
decomposers and small decomposers; however, the rs equals 0.5, which
is not significant. Most of the deviation comw from a single observation
(Spruce, R. H. (6) ). If this item were removed, the relationship between
large and small decomposers would attain statistical significance at the
5% level (r, = 0.69), but since we have no justification for eliminating
the data on the Spruce, R. H. (6) communil;y, the relationship remains
doubtful.
It is also important to note that in Madadyen’s data the predatorherbivore ratio was not constant and did not seem to correlate either
directly or inversely with any other element of the community.
Macfadyen (1963b) points out that, although the various taxonomic
components vary considerably from community to community, the
total picture of metabolism remains remark ably constant. Although in
view of the adjustments and assumptions made, the figures thus derived
must be considered as tentative. From information on bacterial respiration and field experiments with soil reupirshion, Macfadyen estimated
that animal respiration represented from 10 to 20% of the total soil
metabolism. He concluded that the soil fauna is important in its
%atalytic” activity and control of the energy passing through the decomposition cycle.
When the studies on maintenance met,abolism are reviewed as a
group, at least three salient points emerge. First, annual maintenance
metabolism is a better indication of the impmt of a population or group
on an area than are numbers or biomass. However, it was pointed out
by Phillipson, Macfadyen, and O’Connor that respiratory metabolism
rates alone do not represent the full impact of the population. The eating habits, efficiency of digestion, and rate of reproduction can have
D*
93
comprehensive framework, comparing different communities (pages 8,
9) as well as components within the communities. He used data from
several authors in the compilation of this table. The table contained
data from both forest (coniferous and deciduous) and grassland communities.
In Table VII are listed the percentage of animals comprising each
major trophic group as given by Macfadyen and the rank each group
held with equivalent trophic groups of the other communities. I have
used these data to compute a rough carnivore-herbivore ratio and
several generalizations emerge: (1) There is a rather constant percentage
(20 to 33%) of herbivores - this category includes anima@ which reside
in the soil and feed upon algae and roots of’ green plants but not upon
bacteria and fungi. (2) There is an inverse relationship between the percentages of predators and large decomposerig (sig. at the 5% level using
Spearman rank correlation (Siegel, 1956, page 202) ). (3) It would appear
that there is an inverse relationship between the percentages of large
decomposers and small decomposers; however, the rs equals 0.5, which
is not significant. Most of the deviation comw from a single observation
(Spruce, R. H. (6) ). If this item were removed, the relationship between
large and small decomposers would attain statistical significance at the
5% level (r, = 0.69), but since we have no justification for eliminating
the data on the Spruce, R. H. (6) communil;y, the relationship remains
doubtful.
It is also important to note that in Madadyen’s data the predatorherbivore ratio was not constant and did not seem to correlate either
directly or inversely with any other element of the community.
Macfadyen (1963b) points out that, although the various taxonomic
components vary considerably from community to community, the
total picture of metabolism remains remark ably constant. Although in
view of the adjustments and assumptions made, the figures thus derived
must be considered as tentative. From information on bacterial respiration and field experiments with soil reupirshion, Macfadyen estimated
that animal respiration represented from 10 to 20% of the total soil
metabolism. He concluded that the soil fauna is important in its
%atalytic” activity and control of the energy passing through the decomposition cycle.
When the studies on maintenance met,abolism are reviewed as a
group, at least three salient points emerge. First, annual maintenance
metabolism is a better indication of the impmt of a population or group
on an area than are numbers or biomass. However, it was pointed out
by Phillipson, Macfadyen, and O’Connor that respiratory metabolism
rates alone do not represent the full impact of the population. The eating habits, efficiency of digestion, and rate of reproduction can have
D*