Ecological Archives A015-058-A2

Matthew A. Bowker, Jayne Belnap, Diane W. Davidson, and Susan L. Phillips. 2005. Evidence for micronutrient limitation of biological soil crusts: importance to arid-lands restoration. Ecological Applications 15:1941–1951.

Appendix B. Detailed results of regional and microscale community analyses, by environmental variable.

Correlations (r) with ordination axes
       
Habitat characteristic

Axis 1

Axis 2

Axis 3

Microhabitat

Discriminant analysis P

FC

Analyses§
               

Soil depth

0.002

0.077

-0.362

SC

0.01

-0.422

CR,CM,

               

Interspace size

0.021

-0.157

0.252

 -

 -

 -

CR

               

Litter

0.44

0.215

-0.245

SC

<0.0001

-0.261

CR,CM

               

Rock

0.104

-0.191

0.368

IS

<0.0001

0.064

CR,CM

               

Distance to top of slope

0.304

0.03

-0.203

 -

 -

 -

CR

               

P

0.571

0.136

-0.381

SC

<0.0001

-0.035

CR,CM,SEM

               

K-available

0.393

-0.067

-0.228

SC

<0.0001

0.339

CR,CM

               

pH

-0.121

-0.061

0.163

n.s.

0.84

0.230

CR,CM

               

EC, electrical conductivity

-0.131

0.033

0.057

SC

<0.0001

0.035

CR,CM

               

Sand

-0.519

-0.16

0.054

SC

<0.0001

-0.225

CR,CM

               

Clay

0.286

-0.305

0.080

n.s.

0.12

||

CR,CM

               

Silt

0.527

0.353

-0.108

IS

<0.0001

0.318

CR,CM

               

Zn

0.653

0.167

-0.244

SC

<0.0001

-0.039

CR,CM,SEM

               

Fe

0.396

0.214

-0.278

SC

<0.0001

0.290

CR,CM,SEM

               

Mn

0.196

0.476

-0.163

SC

<0.0001

-0.587

CR,CM,SEM

               

Cu

0.404

0.24

0.006

IS

<0.0001

0.286

CR,CM

               

Ca-exchangeable

0.509

0.009

0.019

n.s.

0.55

0.555

CR,CM

               

Mg-exchangeable

0.538

0.036

-0.216

SC

<0.0001

-0.652

CR,CM

               

K-exchangeable

0.469

-0.043

-0.227

SC

<0.0001

-0.627

CR,CM

               

Na-exchangeable

-0.084

-0.277

0.059

SC

0.001

0.340

CR,CM

               

ANP

-0.16

-0.207

0.100

n.s.

0.10

0.535

CR,CM

               

ANP: P

-0.126

-0.262

0.092

SC

<0.0001

-0.136

CR,CM,SEM

               

Solar radiation

-0.407

-0.142

0.157

 -

 -

 -

CR

               

Net radiation

-0.442

-0.125

0.251

 -

 -

 -

CR

               

Potential evapotranspiration

-0.433

-0.116

0.269

 -

 -

 -

CR

               

Average temperature maximum

-0.358

0.111

0.406

 -

 -

 -

CR

               

Average temperature minimum

-0.138

0.004

0.362

 -

 -

 -

CR

               

Precipitation

0.385

0.171

-0.263

 -

 -

 -

CR

               

Precipitation deficit

-0.504

-0.152

0.319

 -

 -

 -

CR

   Notes: Nutrients were measured as: diethylene triamine penta acetic acid-extractable micronutrients (Zn, Mn, Fe, Cu), NaHCO3-extractable P and K (P, K available), and exchangeable cations (Mg, K, Ca, Na exchangeable). 

†  The microhabitat column indicates which microsite class a variable is significantly associated with, when applicable: SC, shrub canopy; IS, interspace.

‡  Fisher's standardized discriminant function coefficients (FC) indicate a variable's relative contribution to a function that distinguishes between microhabitat types.

§  The analyses column lists the analyses in whicheach variable was used: community regional (CR), community microscale (CM), species-level structural equation modeling (SEM).

|| Clay was not used in the discriminant function because it offers no additional information when sand and silt are included.

¶ ANP = acid-neutralizing potential.  



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