9780521861724htl 1..2

The scaling exponents for annual P/B versus M (summed taxa) ranged from

0.24 to0.27 (p<0.01) for Ball Creek, Sutton Stream and Stony Creek, and

were remarkably similar to the predicted exponent of0.25 (Figs.4.3& 4.5). The

scaling exponent for the Ogeechee River (0.50, p<0.01), however, diverged

substantially from this prediction (Figs.4.3& 4.5).

The regression of P versus M was not significant, as predicted, for Ball Creek,

Sutton Stream and Stony Creek, with scaling exponents ranging from0.13 to

0.03 (Fig.4.6). Each of these fell within one SE of the predicted exponent of 0

(Fig.4.3). The scaling exponent for the Ogeechee River, however, indicated a

strong negative relationship between P and M (summed taxa, Fig.4.6) and, like

the P/B values estimated for this community (Fig.4.5), showed a significant

departure from the expected exponent (Fig.4.3). Production by the snag com-

munity of the Ogeechee River was much greater than the other streams, as

indicated by the relative height of the normalization constant for the relation-

ship between P and M (summed taxa, Fig.4.6). This is to be expected, given the

three- to four-fold greater average annual temperature of the Ogeechee River

compared with the other streams (Brownet al., 2004).

The scaling exponents for N versus M (individual taxa) ranged from0.79 to

0.52 (Fig.4.7). Those for the Ogeechee River and Ball Creek fell within one SE,

Stony Sutton

Upper BallOgeechee

Stony Sutton Upper BallOgeechee

–0.60

–0.50

–0.40

–0.30

–0.20

–0.10

0.00

0.10

0.20

0.30

• 1.50


• 1.25


• 1.00


• 0.75


• 0.50


• 0.25

0.00

0.25

0.50

0.75

1.00

N

B

* * *

*

*

* * * *

P

P/B

*

Scaling coefficient (b)
Figure 4.3Summary of regression coefficients
describing the slopes of the relationships
between body size (M) and N, B, P/B and P for the
snag-community of the Ogeechee River and
benthic communities of Ball Creek, Sutton
Stream and Stony Creek. The solid black lines
indicate predicted slopes of the relationships
(i.e. N/M0.75,B/M0.25, P/B/M0.75and
P/M^0 ). The error bars are1 SE.

BIOMASS TURNOVER AND BODY SIZE 61