ENERQETICS AND ANIMAL PRODUCTIVITY
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am specifically referring to that portion of the literature which is concerned with caloric values and transfers.
The first major source of information on energetics of natural communities has its origins in physiological studies dating from the investigations of Lavoisier in the late 18th century. They emphasize the
homeostatic mechanisms of the organism, the iinvestigator exploring the
individual’s response to an environmental stress. Some aspect of the
animal’s metabolic rate is measured during the various stress situations.
When respiration rate or heat production is used as the measure of
response of the animal to stress, the data aro potentially useful in an
energetics analysis. The stress studies themselves, however, are usually
not sufficient for energetics analysis because field data on numbers or
biomass are lacking. The studies of the physiological ecologist (or the
ecological physiologist) are concerned primarily with the individual and
form a tremendous and diverse reservoir of information, useful in
making field estimates.
The second major source of information on energetics of natural communities comes from analysis of maintenance energy by what I refer’
to as the “Bornebusch” approach, which is b,ased on the assessment of
three key parameters - numbers of individuals, biomass, and oxygen
consumption. When these parameters are known for different populations in the field or for different communities, the resulting data can
then be used to compare the impact of the dijfferent populations on the
community or the relative amounts of energy flow through the different
communities. The key factor in a Bornebusch type study is comparison
of the total metabolism of different populations as reflected by respiration rates. Respiration rates can be a sound means of comparing populations, because in most animals about 70% of the assimilated calories
are used for maintenance and thus show up as respiration. From the
community point of view, all of the calories captured aa radiant energy
will eventually be dissipated as heat via respiration (exceptions are peat
bogs and rapidly buried organic deposits). On the other hand, population or community analysis using species diversity or numbers presents
great problems. Here we are comparing unlike elements and more or
less objectively making them equivalent, i.e a species as a unit. The
Bornebusch approach utilizes units which are common to all animals
and plants, i.e. mass and respiratory metabolism. Thus, the comparisons are less subjective.
The third approach to this subject of energetics of natural communities comes from the trophic-dynamic or Undeman school of community
metabolism. The guiding principle in this type of study is the Lindeman
(1942) model. It consists of a flow diagram of energy made up of the
following components: A, , the energy coming into a trophic or feeding
75
am specifically referring to that portion of the literature which is concerned with caloric values and transfers.
The first major source of information on energetics of natural communities has its origins in physiological studies dating from the investigations of Lavoisier in the late 18th century. They emphasize the
homeostatic mechanisms of the organism, the iinvestigator exploring the
individual’s response to an environmental stress. Some aspect of the
animal’s metabolic rate is measured during the various stress situations.
When respiration rate or heat production is used as the measure of
response of the animal to stress, the data aro potentially useful in an
energetics analysis. The stress studies themselves, however, are usually
not sufficient for energetics analysis because field data on numbers or
biomass are lacking. The studies of the physiological ecologist (or the
ecological physiologist) are concerned primarily with the individual and
form a tremendous and diverse reservoir of information, useful in
making field estimates.
The second major source of information on energetics of natural communities comes from analysis of maintenance energy by what I refer’
to as the “Bornebusch” approach, which is b,ased on the assessment of
three key parameters - numbers of individuals, biomass, and oxygen
consumption. When these parameters are known for different populations in the field or for different communities, the resulting data can
then be used to compare the impact of the dijfferent populations on the
community or the relative amounts of energy flow through the different
communities. The key factor in a Bornebusch type study is comparison
of the total metabolism of different populations as reflected by respiration rates. Respiration rates can be a sound means of comparing populations, because in most animals about 70% of the assimilated calories
are used for maintenance and thus show up as respiration. From the
community point of view, all of the calories captured aa radiant energy
will eventually be dissipated as heat via respiration (exceptions are peat
bogs and rapidly buried organic deposits). On the other hand, population or community analysis using species diversity or numbers presents
great problems. Here we are comparing unlike elements and more or
less objectively making them equivalent, i.e a species as a unit. The
Bornebusch approach utilizes units which are common to all animals
and plants, i.e. mass and respiratory metabolism. Thus, the comparisons are less subjective.
The third approach to this subject of energetics of natural communities comes from the trophic-dynamic or Undeman school of community
metabolism. The guiding principle in this type of study is the Lindeman
(1942) model. It consists of a flow diagram of energy made up of the
following components: A, , the energy coming into a trophic or feeding