McCaffrey, Biggam, Johnson-Maynard, and Umiker:
June 04
Week long pitfall and core samples are being taken weekly from the Mosman and
Ramsey farms before and after specific treatments. Sample processing is slow given the large
number of organisms in each sample. In fact, we are still processing samples from last season.
Collecting, sorting, counting, and curating the large number of specimens requires considerable
amounts of time and resources, but until we know which species are of specific importance, we
assume that they all are. This will continue and with a new graduate student in place, it should
proceed faster. We are beginning to classify the organisms into functional groups in order to
better understand their role and importance. We classified the organisms as predators, parasites,
detritivores, herbivores, fungivores or non-trophic. Predators and parasites attack many of the
other trophic groups and non trophic groups, respectively. Detritivores feed on decaying organic
matter, further breaking it down. Herbivores feed on the grass directly. Fungivores feed on the
fungi that are an important group involved in breaking down the organic matter. The non trophic
group related to organisms that are not directly involved with the crop, but are using the habitat.
For example, insects that produce nests in the soil may be important in terms of improving water
infiltration. A limited data set is graphed in Fig. 1.
A new graduate student, Jeff Neufeld, has taken on the specific task of dealing with the
taxonomic issues relating to an important group of insects called springtails. These insects are
generally fungivores and are important in the food web associated with the breakdown of plant
residues. We will be assessing their populations and species compositions across thermal and
nonthermal treatments. We have identified a researcher at Michigan State University who could
be helpful to us and I am trying to arrange a trip for Mr. Neufeld to that lab for instruction on
curating and identification of these insects.
We hypothesize that a multivariate statistical approach will be necessary to identify
associations among the biological and physical response variables. With that in mind, we
undertook preliminary multivariate analyses to assess the relationship between specific insect
functional groups (detritivores, fungivores, and herbivores) and physical factors, including
residual carbon, residual nitrogen, C/N ratios, and ash free residue weight. Of special interests
was the potential role of insects in the process of carbon sequestration. The results were
inconclusive with regard to that specific question, other than to say that there were differences in
responses across years. There were some interesting relationships between herbivores and
nitrogen and C/N ratios, but again, it’s too early to draw too much from this very limited subset
of data: further analyses will be conducted once the full data set is available.
We are ready to have our soil mite species identified and samples will soon be sent to a
specialist at the Ohio State University. We are also collecting mesofauna associated with the
thermal and nonthermal treatments. These insects and spiders are primarily natural enemies of
other insects, including potential grass seed pests such as webworms, cutworms, and grass bugs.
Processing of these samples from last year has begun and I hope to have another graduate student
start soon to work with us on this aspect of the project in coordination with the new Sustainable
Agric. Res. Grant (SARA) that we are working on. I’m waiting to hear about a no cost extension
of the project. I know of a person who would like to start in Aug. If I can’t put him on an
Mean (± SE) no. of organisms
Predators
Parasites
Detritivores
Herbivores Ramsey
Field
Fungivores
Non-trophic
1000
100
10
1
0.1
BMHS
BMH
B&B
0.01
FLB
Mean ± SE no. of organisms
assistantship, I may hire him for summer to help with sampling, etc. Finally, we are establishing
our pitfall traps, etc. at the new SARA location. .
10000
1000
Predators
Parasites
Detritivores
Herbivores
Fungivores
Non-trophic
100
10
M osman
Field
1
0.1
F-R Ch
F-R M
B1H2 Ch
B1H2 M
Treatments
Fig. 1 Number of organisms representing different functional
roles in two grass seed fields. Treatm ent codes for
each field are listed below.
Ramsey Field
FLB
= Full load burn
B&B
=Bale and burn
BMH
=Bale, Mow and Harrow
BMHS
=Bale, Mow, Harrow, System
Mosman Field
F-RCh
=Fallowed Roundup,Chem.
F-RM
=Fallowed, Chem, Mow
B1H2Ch
=Burned01, Harvested 02, Chem.
B1H2M
=Burned01, Harvested 02, Chem, Mow