Geographic and TaxonomicPatterns in the Distribution of Rare

Southeastern Endemics

James C. EstillUGA Center For Applied Genetic Technology

and Department of Plant Biology

Traits Increasing Extinction Risk

McKinney. 1997. Ann. Rev. Ecol. Syst. 28:495-516.

Short Term Goal : Use a biologically meaning definition of rarity to Identify the taxonomic and geographic patterns in the distribution of taxa potentially at risk of extinction in the southeastern US Ultimate Goal: Identify the traits associated with pattern

Ecological meaning of endemic:Species that are relatively spatially limited.

Rare Southeastern Endemics

Endemic 1st used in the medical literature to describe a disease that was limited to a certain geographic area

Jamie’s definition of rare endemic:“A species spatially limited to a biologically significant region with a limited number of occurrences”

Relative - As compared to other species… all species are endemic to Earth

Spatial limitation could be geographic or ecological

Defining the Geographic Area of Interest

When studying biogeographical trends in species richness, it is important to delineate areas that have biologically meaningful boundaries.

Goal: Delineate an area that had some sort of biologically meaningful borders.

Problem: Data that are available are typically delineated by political boundaries.

Defining the Geographic Area of Interest

States South of the Maximum Glacial Extent

Counties Occurringin the HT Domain - Bailey. 1998

1,231 Counties14 States

Obviously Not Perfect

Identifying Rare Southeastern Endemics

2. Distribution entirely limited to the geographic area of interest

3. Species that occur in less than 26 counties

1. Plant taxa that are commonly recognized at the species level (Kartesz, 1994 ). Including hybrids.

Data Sources

State Data Source

Arkansas (Smith 1988)

Florida (Wunderlin, Hansen et al. 1995)

Georgia (Jones and Coile 1988)(Patrick, Allison et al. 1995) (USDA 1999)

Kentucky (USDA 1999)

Louisiana (Thomas and Allen 1993; Thomas and Allen 1996; Thomas and Allen 1998)

North Carolina (Radford, Ahles et al. 1968) (USDA 1999)

South Carolina (Radford, Ahles et al. 1968)(Townsend and T.A.Mousseau )(USDA 1999)

Tennessee (Chester, Wofford et al. 1993; Chester, Wofford et al. 1997)State NHP

Texas (Carr and Diamond 1996) (Schneider 1999)

Virginia (Harvill, Bradley et al. 1992)(USDA 1999)

West Virginia (Strausbaugh and Core 1950s) (USDA 1999)

State Distributionshttp://plants.usda.gov

County DistributionsKral. R. 1983. State FlorasTaxonomic Monographs

Data Management in MS Access

SE Endemic Occurrence Data

Base data set of state occurrencesUSDA Plants Database: http://plants.usda.gov

• All data managed in MS Access

• Query of this database yielded initial list of 2,380 species limited to the 14 states of interest.

• County distribution info gained from numerous state floras and atlases

Species Removed- 766 Occur in dry domain of Texas- 329 Occur in Tropical Domain of Florida- 152 Occur outside United States- 326 Occur in >25 counties- 194 Nomenclature Problems- 117 Unresolved county distributions

482 Species(31 hybrids)

18

402

62ENDANGERED

THREATENED

NOT LISTED

Species: Federal Status

I have generated a unique data set.

Taxonomic Selectivity Patterns

McKinney. 1997. Ann. Rev. Ecol. Syst. 28:495-516.

Short Term Goal : Identify the taxonomic and geographic patterns in the distribution of rare southeastern taxa Ultimate Goal: Identify the traits leading to this pattern

Family Level Taxonomic Selectivity

Of the 307 families that occur in the SE United States, three have more endemics then predicted by a random selection model (p<0.001)

Family Number of SE Endemics

Asteraceae 78

Lamiaceae 38

Sarraceniaceae 14

http://www.masozravky.com/foto_galerie/fotosarracenia.htm

Sarraceniaceae Pitcher Plant Family

AsteraceaeSunflower Family

http://www.science.uwaterloo.ca/biology/jcsemple/heterotheca.htm http://www.uga.edu/~botgarden/GEPSN2b.html

LamiaceaeMint Family

Genus Level Taxonomic Selectivity

Of the 2,191 Genera of plants that occur in the Southeastern states, thirteen have outstanding numbers of rare southeastern endemics (p<0.001)

Genus Number of SE Endemics

Agalinis 8

Chrysopsis 7

Deeringothamnus 2

Dicerandra 7

Hexastylis 5

Leavenworthia 6

Lesquerella 7

Polygonella 4

Rudbeckia 6

Sarracenia 14

Scutellaria 11

Trillium 11

Triphora 3

Family

Scrophulariaceae

Asteraceae

Annonaceae

Lamiaceae

Aristolochiaceae

Brassicaceae

Brassicaceae

Bignoniaceae

Asteraceae

Sarraceniaceae

Lamiaceae

Liliaceae

Orchidaceae

Taxonomic Selectivity Patterns

McKinney. 1997. Ann. Rev. Ecol. Syst. 28:495-516.

Short Term Goal : Identify the taxonomic and geographic patterns in the distribution of rare southeastern taxa Ultimate Goal: Identify the traits leading to this pattern

Occurrence of Endemics

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Total Counties of Occurrence

Nu

mb

er o

f S

pec

ies

Endemics in States

State Rare SE Endemics in StateTotal Number of County

OccurrencesProportion of Counties Containing Endemics

Florida 227 1,370 1.00

Georgia 126 607 0.89

North Carolina 90 399 0.70

Alabama 87 268 0.88

South Carolina 71 165 0.85

Tennessee 64 216 0.60

Texas 55 315 0.71

Louisiana 43 161 0.80

Virginia 31 110 0.31

Mississippi 23 50 0.24

Kentucky 16 53 0.43

Arkansas 16 101 0.65

Oklahoma 10 20 0.12

West Virginia 8 21 0.20

Richness of Rare Southeastern Endemics

Corrections for Species Richness ?

Corrections for total plant species richness are currently not possible given the inconstancies of the data

• Inconsistency in sampling among states- Data not available for AL, MS, and OK- Primary data not available for most states

The county level distribution of most of the native US plants is unknown, and is becoming increasingly unknowable

• Inconsistency in sampling within counties- Distance to herbaria and interstates are currently great indicators of species richness

Epidemic Loss of Herbaria

Data derived from Index Herbariorum (http://www.nybg.org/bsci/ih/ih.html) .

Richness of Rare Southeastern Endemics

Richness of Rare Southeastern Endemics

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

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0.4

0.5

0 500 1000 1500 2000

99.9 % Confidence

Observed I

Spatial Autocorrelation of Endemic Species Richness

Lag Distance (km)

Glo

bal

Mo

ran

’s I

Local Indicators of Spatial Autocorrelation

The counties contributing to the positive global spatial autocorrelation at the 0-60km lag distance.

Global Moran’s I = 0.430

Rarity Weighted Richness Index (RWRI)

∑ == n

ii

county hRWRI

1

1

In addition to richness may want to consider rarity of the endemic species flora for that county

hi = the number of counties that species i occurs inn = number of endemic species in that county

The contribution of any species to the RWRI for a county will range from 0.04 to 1.00

Identifying Outstanding Endemic Floras

Can identify counties with “outstanding endemic floras” by comparing theEndemic Richness to the RWRI.

Outside of 95% and 99% confidence intervals of a linear model

R2 = 0.8836

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12

0 10 20 30 40 50 60

Endemic Species Richness

Rar

ity-

Wei

gh

ted

Ric

hn

ess

Ind

ex (

RW

RI)

Significantly More Unique Significantly Less Unique

Geographic Centers of Endemic Species Richness

Gulf Coastal Plain

Central BasinSouthern Appalachians

AppalachicolaFlorida Panhandle

Central Pennisular Florida

Atlantic Coastal Plain

Combining the geographic analyses allows for the identification of six centers of endemic species richness

Geographic Centers of Endemic Species Richness

Ouachita Mts.

Two minor centers of endemism are also less apparent

NE Alabama

Summary

• Taxonomic selectivity exists for rare southeastern endemics at the Family and Genus level

• Geographic selectivity exists for rare southeastern endemics with well defined centers of endemism

• Overall species richness at the county level is relatively unknown, thus it is difficult to determine the association between endemism and overall species richness

• Now the real work begins

I’d be happy to answer any questions or concernsJamie Estill: jestill@uga.edu

Estill, J.C and Cruzan M.B. 2001. Phytogeography of Rare Plant Species Endemic to the Southeastern United States. Castanea. 66(1-2): 3-23.