PRAIRIES AND GRASSLANDS

 

I. Distribution

A. Six major physiognomic types (Whittaker 1975)

B. Grassland structural types

alpine meadows, temperate grassland, tropical savannah

C. Temperate grasslands of North America:

tall-grass and mixed-grass prairies

short-grass plains of the midwest

palouse (bunchgrass) prairie

California grasslands

desert grasslands of the Southwest

D. Original extent

II. Environment and composition

A. Climate

B. Soils

C. Vegetation

III. Changes

A. Tall-grass prairie

B. Mixed-grass prairie

C. Short-grass prairie

D. California grasslands

E. Palouse prairie

F. Desert grasslands

G. South Puget Sound prairie

IV. Restoration

A. Must be tailored to region

B. Basic approaches:

upgrading an existing degraded prairie

establishing on sites without existing prairie species

C. Fire is an integral component in most prairie systems

CASE HISTORIES

V. Wisconsin Prairie (Cottam, G. 1987. Community dynamics on an artificial prairie. Pages 257-270 in W. Jordan, M. Gilpin and J. Aber (eds.) Restoration Ecology: A Synthetic Approach to Ecological Restoration. Cambridge University Press, New York, 342 p.)

A. Nothing worth preserving: removal of all vegetation

cultivate, herbicides, soil sterilization

B. If there are plants you wish to save:

light disking,burning,raking

C. Site preparation critical for seeds

D. Transplanting

pots, prairie sods

labor intensive, higher success rate

E. Scattering prairie hay (time specific)

F. Success varies, depending on:

quantity of weeds present

amount and timing of precipitation

seed stratification

numerous other variables

G. Prairies heterogeneous

distribution of many spp. clumped

plants generally have broad range of tolerance

if planted within their range, will interact and sort themselves out

VI. Greenspace project in Calgary (R.Revel 1993. Canada's rough fescue grasslands: Sod transplanting in Alberta shows promise. Restoration and Management Notes 11: 117-124)

A. Rough fescue (Festuca scabrella) grassland slated for development

B. Salvage used for a native prairie restoration

C. Seeding options rejected:

unavailability of natives

time, equipment for gathering and preparing native seeds

D. Used commercial, gasoline-powered sod cutters

cut 5 cm deep (thin sod)

raked to remove thatch

sods were rolled to transport (pickup trucks)

E. Restoration site preparation

tilled site

added 4" topsoil

Round-up

F. Installation

hilly site: planted from top of hill to bottom

shrubs and deeper rooted forbs interplanted after sod placed

site watered with hoses after planting

G. Follow-up

initial slow growth as roots established

high species composition, good establishment

VII. Prairie spp. seeding, Chicago (S.Packard 1994. Successional restoration: Thinking like a prairie. Restoration and Management Notes 12:32-39)

A. Collected seed of what he called "conservative" (less dominant) plants

B. Selected as seedbed well-established sodded areas

D. Raked or otherwise scarified sod surface

E. Scattered seeds then raked in

F. Found good representation of seeded plants after 4-5 years

VIII. Frequent mowing, Iowa prairie (M. O’Keefe 1995. Frequent mowing may increase quality of prairie restorations (Iowa). Restoration and Management Notes 13:109-110)

A. Two-hectare newly planted site

B. Planted 1992, hand-broadcast seeds

9 grasses, 42 forbs; collected from nearby remnants

C. Established mowing treatments:

mow when plants reach 12"; mow when plants reach 24"; no mow

D. Mowed to ht of 5"

E. Burned in spring

F. Results: plots mowed at 12" had most prairie spp.

plots mowed at 24" had next most spp.