ENERGETICS A N D ANIMAL PItODUCTIVITY
95
marked effect upon the community - effects which are not indicated
in the Bornebusch type of analysis. Finally, it is of interest to note that
the majority of the investigations were on soil animals or soil communities. This could be due either to tradition or to the fact that the soil provides many species and complex relationships readily accessible in small
areas. The added fact that this system plays an important role in the
economy of man probably also lends impetus to the pursuit of soil study.
ANALYSIS OF COMMU:YITIES
This last group of studies gives us our best figures on animal productivity in natural communities. These studies are concerned not only
with estimates of maintenance energies, but also with the incorporation
of calories into new protoplasm. These growth calories can either fall
prey to another trophic level, or increase the biomass of the population.
The capacity of the population to produce these surplus calories determines the ultimate structure of the community as well as the usefulness
of that community to man. With regard to this last point, we must bear
in mind that the net productivit,y of a natural population is not equivalent to its yield useful to man. If man were to utilize the complete net
production of a population, he would have to aasume the role of predator and decomposer for the entire population. Man begins to approach
this relationship with his domestic animals, but the natural community
presents a different situation.
Investigators utilizing the trophic dynamic approach at the population level were: Golley and Gentry (1964), Odum and Smalley (1959),
Odum et al. (1962), Petrides and Swank (1965), Smalley (1960), and
Wiegert (1964). Only one author (Golley, 1960) has approached the subject of field energetics from the standpoint of energy flow through a
food chain, while two investigators (Engelmann, 1961; Teal, 1962) have
attempted some kind of analysis at the conimunity level. Three of the
papers reported data on homiotherms (Golley, 1960; Odum et al., 1962;
Petrides and Swank, 1965), while the remainder dealt with poikilotherms, particularly insects. Most of the investigators used field data to
create complete energy budgets.
VI. STUDIES WHICH EMPHASIZE THE TROPHIC SCHEME
A. TROPHIC D Y N A M I C A N A L Y S I S O F THE SALT MARSH E C O T O N E
Smalley (1960) working on the insects of a salt marsh has provided
basic information utilized by other authow. His data for the grasshopper, OrchelimumJidicinium, were used in his own 1960 paper, the
paper by Odum and Smalley (1959) and the paper by Teal (1962). His
basic sampling tool was a sweep net, standardized against captures in a
square meter cage placed randomly on the sampling area. With these
95
marked effect upon the community - effects which are not indicated
in the Bornebusch type of analysis. Finally, it is of interest to note that
the majority of the investigations were on soil animals or soil communities. This could be due either to tradition or to the fact that the soil provides many species and complex relationships readily accessible in small
areas. The added fact that this system plays an important role in the
economy of man probably also lends impetus to the pursuit of soil study.
ANALYSIS OF COMMU:YITIES
This last group of studies gives us our best figures on animal productivity in natural communities. These studies are concerned not only
with estimates of maintenance energies, but also with the incorporation
of calories into new protoplasm. These growth calories can either fall
prey to another trophic level, or increase the biomass of the population.
The capacity of the population to produce these surplus calories determines the ultimate structure of the community as well as the usefulness
of that community to man. With regard to this last point, we must bear
in mind that the net productivit,y of a natural population is not equivalent to its yield useful to man. If man were to utilize the complete net
production of a population, he would have to aasume the role of predator and decomposer for the entire population. Man begins to approach
this relationship with his domestic animals, but the natural community
presents a different situation.
Investigators utilizing the trophic dynamic approach at the population level were: Golley and Gentry (1964), Odum and Smalley (1959),
Odum et al. (1962), Petrides and Swank (1965), Smalley (1960), and
Wiegert (1964). Only one author (Golley, 1960) has approached the subject of field energetics from the standpoint of energy flow through a
food chain, while two investigators (Engelmann, 1961; Teal, 1962) have
attempted some kind of analysis at the conimunity level. Three of the
papers reported data on homiotherms (Golley, 1960; Odum et al., 1962;
Petrides and Swank, 1965), while the remainder dealt with poikilotherms, particularly insects. Most of the investigators used field data to
create complete energy budgets.
VI. STUDIES WHICH EMPHASIZE THE TROPHIC SCHEME
A. TROPHIC D Y N A M I C A N A L Y S I S O F THE SALT MARSH E C O T O N E
Smalley (1960) working on the insects of a salt marsh has provided
basic information utilized by other authow. His data for the grasshopper, OrchelimumJidicinium, were used in his own 1960 paper, the
paper by Odum and Smalley (1959) and the paper by Teal (1962). His
basic sampling tool was a sweep net, standardized against captures in a
square meter cage placed randomly on the sampling area. With these