Managed Grazing in Riparian Areas

MANAGED GRAZING IN RIPARIAN AREAS PAGE 15

cording to environmental conditions (Clary andLeininger 2000) For example Four-inch (10 cm) stubble will usually main-

tain plant vigor trap sediment and protectsoils from compaction when trampled

In woody streambanks moving livestock af-ter they have grazed the forage to 68 inches(1520 cm) may be necessary to ensure thatthey are not feeding on willows or other ri-parian trees because of a lack of non-woodyforages

Stubble height is not a useful guide in areaswhere streambanks are rocky or wherewoody vegetation dominates in the riparianzone

Seasonality of rSeasonality of rSeasonality of rSeasonality of rSeasonality of rotational grazing prac-otational grazing prac-otational grazing prac-otational grazing prac-otational grazing prac-tices in healthy riparian areastices in healthy riparian areastices in healthy riparian areastices in healthy riparian areastices in healthy riparian areas Besides du-ration of grazing the time of year when livestockare allowed access to riparian areas is also criti-cal to maintaining and restoring riparian healthFactors that determine the appropriate time tograze animals in riparian areas include Riparian soil moisture following snowmelt

rainfall and heavy streamflows

Dominant type of riparian vegetation and itsperiods of peak growth and dormancy

Reproductive characteristics of critical ripar-ian plants do they reproduce vegetatively orby seed If by seed when does it set

Freeze and thaw cycles during the winterRiparian areas should not be grazed when

they are wet and most vulnerable to compactionIn the northern US this means excluding ani-mals from riparian areas during late winter snow-melts and spring rains and not allowing animalsin until the soil dries Similarly in areas withheavy late-season rains livestock should bemoved out of riparian areas in the fall

Timing of riparian grazing is important forpreventing erosion and the degradation of soiland water quality In the spring grazing shouldbe delayed until vegetation completely covers theriparian soil This ensures that animals do notdislodge bare soils and cause erosion Fall graz-ing can be used in some areas if it is carefullymonitored leaving enough vegetation at the endof the season to protect against spring runoff anderosion Thus riparian areas should either begrazed in the early fall to allow for forage re-

growth before winter or grazed later in the fallbut only on a limited and well-monitored basis

Timed grazing can also be used to protecthealthy vegetative growth in riparian areas Pe-riodic grazing can be used to remove the apicalmeristems or top portions of grasses and sedgesThis promotes vegetative reproduction by stimu-lating the sprouting of additional stalks or tillers(Mosley et al 1998) However in areas whereannual plants are critical components of the ri-parian ecosystem grazing should not occur whenthese species are setting seed

Table 5 provides a summary of environmen-tal conditions to consider when deciding whichseasons are most appropriate for riparian graz-ing in your area

A report from the Saskatchewan RiparianProject (Huel 1998) describes how careful tim-ing and reduced duration of grazing in ripar-ian areas improved environmental conditionsand productivity on a ranch in the east-cen-tral part of the province

The 3700 acre pasture had previously beendivided into two very large paddocks whichwere grazed continuously throughout the sum-mer by two herds of cattle The cattle spentmost of their time close to the creek over-grazing this area while areas farther awaywere hardly grazed at all This resulted inpoor riparian condition productivity and se-vere damage to the streambanks In 1993 agrazing management plan divided the twolarge paddocks into eleven smaller units andcreated additional water sources The ripar-ian area was divided into three paddocks oneor two of which are rested each year Whenthese paddocks are grazed gazing is deferreduntil the end of summer These practiceshave improved the condition and productivityof the riparian area considerably as indicatedby plants returning to the areas of bare soilon the streambanks These environmentalbenefits have been achieved with no overallreduction in livestock numbers

Understand How Different LivestockUnderstand How Different LivestockUnderstand How Different LivestockUnderstand How Different LivestockUnderstand How Different LivestockSpecies GrazeSpecies GrazeSpecies GrazeSpecies GrazeSpecies Graze Grazing managers should un-derstand the grazing patterns of the animals theymanage (Stuth 1991) Different species prefer