Savanna Restoration

Pinyon-juniper savanna

Predominantly juniper

Western U.S. and Sierra Madre of Mexico

Warm, dry limit of coniferous forests

Foothills, low mountains, mesas

1500-2000 m in western mountains

300-600 m in plains

 

Montane

Juniperus occidentalis, J. osteosperma,            J. scopulorum

Pinus monophylla, P. edulis

Plains

Juniperus virginiana

 

Pine savannas

Ponderosa pine (Pinus ponderosa)

Mostly in central and southern Rocky Mtns. and south into Mexico

Also in xeric regions of Pacific Northwest

On the Great Plains

South Dakota, Idaho, Washington, Oregon, British Columbia

Ponderosa pine is lowest-elevation commercially valuable tree throughout its range.

300 m in northern Rockies

2200 m in Sierra Madre

At upper limit, merges with forests of Ponderosa pine, Douglas fir, white fir, grand fir

At lower limit, grades into bunchgrass-dominated grasslands and shrublands.

 

Longleaf pine (Pinus palustris)

About a quarter of longleaf pine forest is considered to be savanna.

Natural range is a belt 150-250 km wide along the Atlantic and Gulf coasts

Formerly continuous below 70 m and occasionally in sites up to 600 m; now quite fragmented

Warm, humid subtropical climates typical in longleaf pine savannas.

Soils highly weathered, dry or wet

Sandier soils support grassy understories and fires are common

Aristida stricta (wiregrass) is common associate

Slash pine (P.elliotii) and loblolly pine (P. taeda) have better establishment and faster growth.

They often are used to replace longleaf pine in forests grown for harvest.

 

Oak savannas

Californian

Dominated by blue oak (Q. douglasii)

Encircle central valley at 60-1200 m.

Southwestern

Mostly Mexico, rest in Arizona, New Mexico and trans-Pecos in Texas

At low (1000-2000 m) and dry locations where encinal (oak woodland) grades into desert grassland.

Emory oak (Q. emoryi) has broadest distribution

Midwestern

Discontinuous from Minnesota to Texas

At time of settlement, made up a continuous band of 20 million ha.

Currently a “globally imperiled” ecosystem

Dominated by winter-deciduous oaks: post oak (Q. stellata), blackjack oak (Q. marilandica). 

Commonly found: black hickory, white oak, black oak, eastern redcedar.

 

Mesquite savannas

Mesquite savannas cover 35  million ha in southwestern U.S. and northern Mexico.

They are expanding into grasslands

Occur at low elevations (below 1800 m in U. S.)

Often form abrupt boundary with pine, P-J or oak woodlands above and desert grasslands below.

In humid areas they may grade into thorn woodlands or pine forests.

 

Mesquite

Often mesquite savannas are dominated by a single species of mesquite.

In S. Texas and N. Mexico, co-dominant with Acacia spp.

Rocky mountains and Sierra Nevadas form a divide:

Velvet mesquite (Prosopis velultina) to west

Honey mesquite(Prosopis glandulosa) to east

 

Case Histories:

Kerr Wildlife Management Area, Texas Hill Country

Management actions:

1.  1964-66, large acreage of juniper cleared for posts

2.  500 acre plot left for Golden Cheek Warbler habitat

3.  Grazing and rotation were tried, did not suppress juniper regrowth

4.  1979, burning instituted

5.  Cattle grazed immediately after burns, taking 65% of prickly pear cactus

6.  Each year 800-1000 acres set aside for late winter burn

7.  Bare hotspots under burned brushpiles are baited with saltlicks; cattle deposit seeds in manure

8.  Deer population exploded (1 deer per 10 acres is carrying capacity), lowered diversity of everything, juniper began to spread.

9.  Currently added to management is a both sex deer hunt to lower density to carrying capacity.

10.  7 ˝  foot tall game fence was installed around perimeter of site to keep out neighboring deer and non-native game animals

11.  Dense cedar left in canyons and steep lands for black-capped vireo and golden cheek warbler.

12.  Birds are parasitized by brown-headed cowbird. (Follows livestock; originally called the buffalo bird)

13.  Cowbirds are trapped by grazing prior to vireo nesting period; this attracts cowbirds; mobile cowbird trap moves with the herd; they are fairly easy to trap.

 

Water Quality Protection Lands, Barton Creek Aquifer Recharge Zone, Austin, Texas

A.  Development threatened source of water and water quality in Barton Springs, an Austin sacred site.

B.  Proposition 2, a 65 million dollar bond election was passed in 1998 to purchase land in the Barton Springs watershed and recharge zone

C.  Lands were purchased for protection, currently up to 15,000 acres.

D.  Lands to be managed for water quality and recharge quantity protection

E.  Best science indicated that <15% woody plant cover provided maximum  recharge.

F.  Management available:

                                1.  Prescribed fire most cost-effective

                                2.  Prescribe grazing more expensive, but viable option

                                3.  Prescribed mowing

                                4.  Brush removal and invasive species control

                                5.  Seeding

                                6.  Container plants.

 

Example prescription for a parcel

  1. All management should take place outside of golden cheek warbler breeding season (Mar 15 to May 15), or when warblers are not present.
  1. If deer population is high, and site is greater than 500 acres, authorize public hunt.
  1. Maintain mature juniper stands as golden cheek warbler habitat.
  1. Maintain open grassland with initial mechanical brush removal, followed by burning, mowing or haying every 2-4 years.

5.  If any juniper removed, sow sites with rapid revegetation seed mix.