The effect of tallgrass prairie fragmentation on the diversity of
insects.
Kristal Stoner
University of Nebraska at Lincoln
School of Biological Science 348 Manter Hall, Lincoln 68588
Insects are affected by decreasing and fragmented habitat. It is
important to
determine the factors that are important to identify optimal
conditions in
remaining
fragments to support insect diversity. The factors evaluated in this
study
that may
impact insect diversity include degree of fragmentation, habitat
heterogeneity and
management practices. The degree of habitat fragmentation, or patch
isolation could
affect insects with restricted dispersal ability more severely.
Habitat
heterogeneity describes how much variation exists within the
landscape.
In
Lancaster county, prairie is limited to primarily two types of land
management that
influence insect habitat: grassland grazed by cattle, and managed for
hay
production. I sampled insects using a sweep net in 36 fragments
ranging
from .25
acres to 600 acres from both types of management. The diversity of
plants,
biomass
of vegetation and number of flowering plants was sampled for each
site.
Preliminary results suggest that the area of a fragment does not
have an
effect on
overall insect diversity. I separated the insects into feeding guilds;
herbivores,
predators and pollinators. Herbivore diversity appears to decline as
biomass
increases. I also separated groups by family. Orthoptera,
Curculionidae
and
Cicadellidae appear to be affected by decreasing area. Currently I am
in
the
process of sorting insects from summer of 2001. I also plan to
determine
if the
diversity of the plant community affects insect diversity and guild
diversity. I
also plan to determine if patch isolation affects insects
differentially
based on
dispersal ability.
