Goats as Grazing Animals for Invasive
Plant Management 2005-2006
Goats eating Oriental bittersweet.Jordan
Bill Jacobs, Kathy Schwager, Marilyn Jordan: The Nature Conservancy
Karen Kazel: Suffolk County Farm
SUMMARY: The Nature Conservancy carried out this goat grazing project at the Suffolk
County Farm in 2005-2005. Results were presented at the August 24, 2006 meeting of the
Long Island Invasive Species Management Area (LIISMA).
Goats are great at eating woody plants, and will even eat the bark off of trees. They also
eat some herbaceous plants, but first they eat woody species, then they move on to
herbaceous plants in order of their gastronomic preference. Mugwort (Artemisia vulgaris)
is down near the bottom of the goat menu. Swallow-wort (Cynanchum rossicum and C.
louisae) are toxic. Grass cover tends to either increase slightly, or remain unchanged, as
long as there are plenty of other plants to eat.
Goats eat more intensively "close to home" (i.e. location of water and shelter) than farther
away. Thus a long narrow pen like the one we used is not the ideal shape for uniform
woody control, though good for seeing effects of browse along an intensity gradient.
Browsing doesn't kill woody plants after just one summer of goat exposure, so when goats
are removed the woodies (and other plants) grow back. Repeated browsing for a couple
of years, or following one year of browse with herbicide in year two, would be required for
permanent kill of woody plants (and possibly herbaceous perennials).
So goats are good for woody control in grasslands. Not good for forests where abundant
deer already fill the goat niche much too well.
Text, data analysis and photograph by Marilyn J. Jordan, Ph.D. Senior Conservation Scientist, The
Nature Conservancy on Long Island. Uplands Farm Sanctuary. 250 Lawrence Hill Rd., Cold Spring
Harbor, NY 11724 USA (631) 367-3225 mjordan@tnc.org
Goat pen 25 ft x 370 ft
1
plot 1 plot 2
post #
7
10
PEN #1
plot 3
13
1
20 21
PEN #2
Pen 1 grazed 4/14/06 to 5/21/06
Monitored 1st time: August 15, 2005
2nd
Monitored
time: June 29, 2006
Grazed 5 weeks; ungrazed 6 weeks
2
24
1
27
2
37 38
PEN #3
Pen 2 & 3 grazed 5/21/06
Monitored: June 29, 2006
Grazed 5 weeks
4=UNGRAZED
Pen 1 Before & After Grazing
2005 (before)
2006 (after)
Grazed 5 weeks; ungrazed 6 weeks
Effect of Goat Grazing
2005 vs. 2006 (pen 1, plots 1-3)
100
90
Before grazing
After grazing
80
Percent Cover
70
60
50
40
30
20
10
0
Celastrus
orbiculata
Lonicera
japonica
Prunus
serotina
Rosa
multiflora
Grasses
Artemisia
vulgaris
Goat pen | Sheep pen
Goats prefer woody vegetation whereas sheep prefer herbaceous.
Grazed Pen #2 | Ungrazed Pen #4
June 29, 2006
Grazed and Ungrazed
Grazed Pen #3 | Ungrazed Pen #4
Grazed and Ungrazed Hedgerow, 2006
<2 m height
80
70
Ungrazed <2m
Grazed <2m
Percent Cover
60
50
40
30
20
10
0
Celastrus
orbiculata
Lonicera
japonica
Prunus
serotina
Rosa
multiflora
Grasses
Artemisia
vulgaris
Bark eaten
off trees
Japanese honeysuckle
Multiflora rose
THE END