Biology Reference
In-Depth Information
species. However, Phlox, Rosa, and Rhus all showed significant negative cor-
relations between seed mass and leaf removal. Meristem removal had a more
negative effect than leaf removal on flower number in Phlox and on both
flower number and seed mass in Rosa.
Conclusions
Meristem removal caused a greater response than defoliation alone in both
Phlox and Rosa, which suggests that meristem loss has a greater effect on re-
production. The combination of leaf and meristem removal as well as recruit-
ment limitation by deer, which selectively browse for these species, is likely to
be one factor contributing to their low abundance in prairies.
Background
Herbivory has the potential to impact every stage in a plant's life [1], and thus
influences where a plant can grow and its abundance [2]. Different kinds of her-
bivory have differential impacts on plants. Herbivory can reduce resource avail-
ability and subsequently have indirect impacts on plant reproduction [3]. Both
meristem damage [4] and leaf damage [3] have been shown to negatively impact
components of plant fitness such as survival, flower number, and fruit production
[1,4-6].
Herbivores may also feed selectively on specific plant species or tissues, which
can lead to increased mortality or slower growth rates of damaged individuals [2].
Insect herbivores can directly limit seed production and lifetime fitness by feeding
on inflorescences [7]. Mammalian herbivory has been shown to be strong enough
to significantly limit the abundance of a plant species [8-10]. Deer in particular
have influenced the composition of plant communities in the northeastern and
north-central United States [11,12].
Deer have been shown to reduce the proportional rate of increase in the height
of some woody species [13]. It also has been suggested that deer browsing can
significantly reduce the growth rate of herbaceous plants [11]. Deer herbivory
typically involves the removal of entire leaves and terminal meristems, and re-
duces the proportion of flowering shoots [11], and has the potential to effect
reproductive success of browsed plants. For example, deer browsing reduced the
number of flowers and proportion of large fruits produced by the forb, Lactuca
canadensis[14]. However, there is little known how browsing influences plant
fecundity [11].
The objective of this study was to identify the effects of leaf and meristem
damage on fruit and flower production in four species of prairie plants that are
