Plant Control 
TVA's control of plants contributing to anopheline breeding s Be ei numerous 
species that are also objectionable in waterfowl habitat. Examples : ete 
vegetation are alligator-weed (Alternanthera philoxereides) lotus | Betumbe 
pentapetala), lizardtail (Saururus cernuus), cattail (Typha latifolia), giant 
cutgrass (Zizaniopsis miliacea), and water~tolerant woody species, mainly button- 
bush (Cephalanthus occidentalis) and willow (Salix SPPeo)o On the desirability 
of controlling these pest plants there is complete unanimity, but on the manage- 
ment of other vegetation there is likely to be divergence. The objectives are 
basically different in that for malaria control, permanent removal of practically 
all kinds of vegetative growth is desirable, whereas for wildlife, certain kinds 
of plants need to be controlled if they compete with or preclude the growth of 
more valuable vegetation. In other words, the object in developing wildlife 
environment is not so much the destruction of plants as the replacement of pest 
species by more useful ones. 
Shoreline Conditioning 
Shoreline conditioning for malaria control in the TVA reservoirs involves 
several practices. Among these are shoreline grazing, cutting of coppice, and 
area mowing and burning. These different procedures have diverse effects on 
waterfowl habitat -- some of them harmful and some beneficial. 
Intensive grazing of shoreline vegetation along the zone of fluctuation is 
harmful since some waterfowl plants, such as wild millet (Echinochloa crusgalli), 
are eaten readily by cattle. Where ducks are to receive consideration in the TVA 
region, restriction of grazing is advisable. 
Control of woody growth by fall and winter cutting is advantageous since it 
allows herbaceous species to dominate along the reservoir margins. In such 
herbaceous vegetation there usually are valuable waterfowl plants, such as wild 
millet, rice cutgrass (Leersia oryzoides), smartweeds (Polygonum spp.), and chufa 
(Cyperus esculentus). Unfortunately, control of coppice does not contribute to 
the suppression of weedy herbaceous species, such as purpletop grass (Panicum 
agrostoides), and cattail. 
Area mowing and burning of vegetation on reservoir margins may or may not 
hamper waterfowl, depending on when the operations occur. Early removal of 
vegetation by these methods before seeds are matured and dropped destroys food 
supplies for ducks and limits reproduction of duck food plants during future 
seasons. However, if mowings or burnings are delayed until after the seeds have 
been dropped, usually after the first frost, the loss of waterfowl food will not 
be severe. 
Investigations made on the Wheeler Refuge in 192-3 revealed that TVA crews 
burning the marginal zone of marsh vegetation scared birds away from the immediate 
locality. Continued observations showed that birds stayed away from these places 
from a few days to three weeks depending on a variety of factors, such as rising 
water level, influx of new birds, or other conditions that might cause waterfowl 
redistribution. Eventually, however, the ducks returned to the burned areas and 
