Birds in the Midst of Change

Great Salt Lake Dynamics

• Natural

• Man caused

Natural Conditions

• Climate: a factor in long term trends

• Annual variation

Historic Lake ElevationsAn Indicator of Climate

Historic Lake ElevationsAn Indicator of the Annual Water Cycle

Lake elevation measurement sites

Anthropogenic Influences on Lake Ecology

• Highlights from history

• Substantive effects

1850Highlights from History

1870188018901900191019201930194019501960197019801990

Substantive Effects:

Diking is responsible for the creation of four distinct ecological units.

• North Arm• South Arm• Bear River Bay• Farmington Bay

Substantive Effects:

Necessary construction to the Southern Pacific causeway in the 1980s has created a salt trap in the North Arm.

Substantive Effects:

Current upstream water consumption reduces the standing lake elevation by an estimated five feet (Arnow 1980).

Substantive Effects:

Of 400,000 acres of lacustrine wetlands 50% are currently under management by state, federal and non-government organizations.

Substantive Effects:

Exotic fish (i.e., carp and gizzard shad) were introduced into managed wetland systems and water storage impoundments.

Substantive Effects:

Nearly 200,000 acres on the periphery of Great Salt Lake are leased properties for mineral extraction and other industrial uses (DSLF 1996).

Substantive Effects:

In addition to mineral extraction, shorelines have been significantly altered by:

• road and railroad construction• WMA diking• power line development• other human activities

Substantive Effects:

The commercial harvest of brine shrimp cysts, and other shrimp biomass, at times exceeds 200,000,000 lbs. annually.

Avian Use and Responses to Change

• Nine examples of GSL species and their response to change.

American White PelicansTwo decades of breeding adults

1963-2000 Gunnison Island White Pelican Breeding Adult Population

0

5,000

10,000

15,000

20,000

25,000

196319641972197319741976198019811982198319841985198619871988198919901991199219931994199519961997199819992000

Bre

ed

ing

Ad

ult

s

Eared Grebes

Great Salt Lake Eared Grebe Geographic Distribution Measured against Lake Elevation

Year Elevation Salinity (%) North Arm

Salinity (%) South Arm

Grebe Pop. North Arm

Grebe Pop. South Arm

1982 4200 26 10.5 Few 1,400,000 1986 4211 17 6 4,000 Few 1987 4210 17 6 3,500 Few 1989 4205 18 10 17,732 30,006 1990 4203 19 13 72,472 84,093 1991 4202 22 13.5 2,830 47,379 1992 4200 25 15 Few 156,210 2000 4202 26 9.5 Few 1,127,300

Tundra Swan

1960-70Swan concentration area

1990s Swan concentration area

Ogden Bay WMA

Bear River Refuge

White-faced IbisStrategic Nesters

1998

1999

2000

2001

California GullBreeding Adult Population

Year Breeding Adults Surveyors 1931 81,700 Behle 1983 80,237 Paul 1992 154,200 Robinette 1994 160,000 Paul/Jehl

Snowy Plover

Snowy Plover, master of dynamic habitats:

• Double brood in optimum conditions

• Long lived ( survival rate 2.7)

• Exploiter of ephemeral habitats

Changes in Distribution and Available Snowy Plover Nesting Habitat 1990-93 at Focal Study Sites, (Paton 1994) Focus Area % Habitat Decline Factor for Decline Howard Slough 56 Re-vegetation Layton Marsh 74.7 Re-vegetation

Wilson’s Phalarope

Annual WIPH Estimates

-

100,000

200,000

300,000

400,000

500,000

600,000

700,000

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Year

The New Horizon:Integrated Conservation