Report - ICP Forests

82 3. Intensive Monitoring
Table 3.4.4-7: Change in mean Ellenberg indicator value (+ number of species) between the first and last relevé.
Only relevés made at intervals of > 6 years were used. Mean = mean value over both observation dates, N = number
of observations (i.e., number of plots with Ellenberg value present in both years), Diff = MEAN [(Ellenberg value
in last relevé) - (Ellenberg value in first relevé)], T = t-value of difference, P = P-value of difference.
Indicator Mean N Diff T P
light (L) 5,0 152 0,016 0,489 0,63
temperature (T) 5,3 113 0,000 0,002 1,00
continentality (K) 3,4 141 -0,023 -0,972 0,33
humidity (F) 5,2 128 0,046 1,648 0,10
acidity (R) 5,5 112 -0,013 -0,287 0,77
nutrients (N) 5,2 122 0,107 2,569 0,01
number of species 11,8 161 1,410 4,742 0,00
Table 3.4.4-8: 'Minimal' model to explain the change in Ellenberg's N using EMEP deposition estimates in the
initial 'full' model. TMV = Top Marginal Variance = the drop in explain variance when omitting this term from the
model. Significance: the sign is the sign of the regression coefficient, absolute value: 1 = P < 0.05, 2 = P < 0.01, 3 =
P < 0.001. N = 99. The negative 'unexplained' variance is due to interaction effects.
Variable
TMV
Latitude climate 7,80% -2
Fagus tree 4,19% -1
mediterr. oak tree 6,01% -2
NO3 (1995) EMEP 8,65% 2
undetermined -14,50%
total expl.
var. 12,14%
Table 3.4.4-10: 'Minimal' model to explain the change in the number of species. EMEP deposition estimates were
included in the 'full' model however removed in the selection process because their effect was not significant. N =
133. Further explanation see Table 3.4.4-8.
Variable
TMV
Compartment
significance
Table 3.4.4-9: 'Minimal' model to explain the change in Ellenberg's N, using throughfall, bulk, calculated and
EMEP estimated deposition as terms in the initial 'full' model. Explanation see Table 3.4.4-8. N = 42.
Variable Compartment
TMV significance
Ca organic 7,22 1
N/C mineral 13,09 -2
Fagus tree 17,29 -2
mediterr. oak tree 15,22 -2
Latitude climate 29,29 -3
NO3 throughfall 12,87 2
NO3 (1995) EMEP 7,41 1
undetermined -64,37
total expl. var. 38,03
Compartment
significance
K organic 10,34 3
CEC mineral 13,14 3
Mediterranean climate 6,77 -2
undetermined -9,05
total expl. var. 21,2