Wild horses
19/04, 2021
Rewilding
Study site (Mols Bjerge National Park)
- 22 sites (Blocks)
- 5 Treatments in each
Methods
Treatments
In each block 5 treatments
- Control: All year grazing no exclousure
- Mowing: permanent exclousure but mowing once a year
- Permanent exclosure: No grazing all year
- Summer exclosure: winter grazing
- Winter exclosure: summer grazing
Mixed effects linear model
- Richness: GLMM, Poisson family
- Diversity: LMM, for shannon index
Plant litter GLMM, Binomial family
- Blocks as random effect
control for the effect of regional drought in 2018 (Abs(Year - 1))
Model
y ~ aspect + Elevation + InitialHabitat + I(abs(YEAR -
1)) + I((YEAR - 1)^2) + slope + Treatment:InitialHabitat +
YEAR:InitialHabitat + YEAR:Treatment + YEAR:Treatment:InitialHabitat +
(1 | BlockNo)
- All possible combination of models
- Rank by AICc
- Full Model Average of delta AICc < 2
Effect of drought
Effect of drought (Abs value - 1)
Results
Species richness
Species richness (Selected models)
| (Intercept) | I((YEAR - 1)^2) | I(abs(YEAR - 1)) | aspect | Elevation | InitialHabitat | slope | InitialHabitat:YEAR | Treatment:YEAR | R2m | R2c | AICc | delta | weight |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.94 | NA | 0.16 | NA | 0.01 |
|
NA |
|
|
0.51 | 0.79 | 2511.75 | 0.00 | 0.21 |
| 2.07 | NA | 0.16 | NA | NA |
|
NA |
|
|
0.49 | 0.79 | 2512.31 | 0.56 | 0.16 |
| 1.92 | -0.03 | 0.22 | NA | 0.01 |
|
NA |
|
|
0.51 | 0.79 | 2512.61 | 0.86 | 0.14 |
| 1.97 | NA | 0.16 | NA | 0.01 |
|
-0.01 |
|
|
0.51 | 0.79 | 2512.80 | 1.05 | 0.12 |
| 2.05 | -0.03 | 0.22 | NA | NA |
|
NA |
|
|
0.49 | 0.79 | 2513.16 | 1.41 | 0.10 |
| 1.91 | NA | 0.16 | 0 | 0.01 |
|
NA |
|
|
0.51 | 0.79 | 2513.29 | 1.53 | 0.10 |
| 2.11 | NA | 0.16 | NA | NA |
|
-0.01 |
|
|
0.48 | 0.79 | 2513.54 | 1.79 | 0.09 |
| 1.95 | -0.03 | 0.22 | NA | 0.01 |
|
-0.01 |
|
|
0.51 | 0.79 | 2513.67 | 1.91 | 0.08 |
Species richness (Response plot)
Species richness Treatment significance
| term | estimate | std.error | statistic | p.value |
|---|---|---|---|---|
| TreatmentControl:YEAR | 0.046 | 0.019 | 2.399 | 0.016 |
| TreatmentMowing:YEAR | 0.041 | 0.020 | 2.006 | 0.045 |
| TreatmentSummerExclosure:YEAR | 0.043 | 0.019 | 2.223 | 0.026 |
| TreatmentWinterExclosure:YEAR | 0.068 | 0.019 | 3.586 | 0.000 |
Species richness Treatment significance plot
Species diversity
Species diversity (Selected models)
| (Intercept) | I(abs(YEAR - 1)) | InitialHabitat | InitialHabitat:YEAR | Treatment:YEAR | AICc | delta | weight |
|---|---|---|---|---|---|---|---|
| 1.41 | 0.11 |
|
|
|
466.67 | 0.00 | 0.65 |
| 1.56 | 0.11 |
|
NA |
|
467.91 | 1.24 | 0.35 |
Species diversity (Response plot)
Species diversity Treatment significance
| term | estimate | std.error | statistic | p.value |
|---|---|---|---|---|
| TreatmentControl:YEAR | -0.013 | 0.082 | 0.157 | 0.875 |
| TreatmentMowing:YEAR | -0.048 | 0.088 | 0.543 | 0.587 |
| TreatmentSummerExclosure:YEAR | -0.046 | 0.082 | 0.566 | 0.571 |
| TreatmentWinterExclosure:YEAR | 0.004 | 0.082 | 0.049 | 0.961 |
| TreatmentPermanentExclosure:YEAR | -0.155 | 0.026 | 6.023 | 0.000 |
Species diversity Treatment significance plot
Plant litter
Plant litter (Selected models)
| (Intercept) | I((YEAR - 1)^2) | I(abs(YEAR - 1)) | aspect | InitialHabitat | slope | Treatment:YEAR | R2m | R2c | AICc | delta | weight |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 4.56 | 1.66 | -3.60 | NA |
|
NA |
|
0.74 | 0.74 | 268.34 | 0.00 | 0.51 |
| 4.78 | 1.66 | -3.61 | NA |
|
-0.03 |
|
0.74 | 0.74 | 269.76 | 1.43 | 0.25 |
| 4.83 | 1.66 | -3.61 | 0 |
|
NA |
|
0.74 | 0.74 | 269.79 | 1.45 | 0.25 |
Plant Litter (Response plot)
Plant litter Treatment significance
| term | estimate | std.error | statistic | p.value |
|---|---|---|---|---|
| TreatmentPermanentExclosure:YEAR | 0.3579814 | 0.3193980 | 1.1208003 | 0.2623729 |
| TreatmentControl:YEAR | -0.1814919 | 0.3469593 | 0.5230927 | 0.6009097 |
| TreatmentMowing:YEAR | -1.3336411 | 0.7263086 | 1.8361908 | 0.0663294 |
| TreatmentSummerExclosure:YEAR | 0.2506042 | 0.3254375 | 0.7700532 | 0.4412683 |
| TreatmentWinterExclosure:YEAR | -0.2686538 | 0.3528684 | 0.7613428 | 0.4464523 |
Plant litter Treatment significance plot
Graminoids
Graminoids (Selected models)
| (Intercept) | I((YEAR - 1)^2) | I(abs(YEAR - 1)) | aspect | Elevation | InitialHabitat | slope | InitialHabitat:YEAR | Treatment:YEAR | R2m | R2c | AICc | delta | weight |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -1.45 | NA | 0.59 | NA | NA |
|
NA | NA |
|
0.88 | 0.88 | 462.68 | 0.00 | 0.26 |
| -1.78 | NA | 0.60 | 0 | NA |
|
NA | NA |
|
0.81 | 0.82 | 463.33 | 0.65 | 0.19 |
| -1.26 | NA | 0.59 | NA | NA |
|
-0.03 | NA |
|
0.88 | 0.88 | 463.92 | 1.23 | 0.14 |
| -1.58 | NA | 0.60 | 0 | NA |
|
-0.03 | NA |
|
0.79 | 0.80 | 464.03 | 1.35 | 0.13 |
| -1.55 | NA | 0.59 | NA | 0 |
|
NA | NA |
|
0.79 | 0.80 | 464.60 | 1.92 | 0.10 |
| -1.20 | 0.28 | NA | NA | NA |
|
NA | NA |
|
0.89 | 0.89 | 464.61 | 1.93 | 0.10 |
| -1.03 | NA | 0.58 | NA | NA |
|
NA |
|
|
0.90 | 0.90 | 464.67 | 1.99 | 0.09 |
Graminoids (Response plot)
Graminoids Treatment significance
| term | estimate | std.error | statistic | p.value |
|---|---|---|---|---|
| TreatmentPermanentExclosure:YEAR | -0.441 | 0.167 | 2.645 | 0.008 |
| TreatmentControl:YEAR | -0.247 | 0.212 | 1.164 | 0.244 |
| TreatmentMowing:YEAR | 0.559 | 0.267 | 2.094 | 0.036 |
| TreatmentSummerExclosure:YEAR | -0.397 | 0.215 | 1.846 | 0.065 |
| TreatmentWinterExclosure:YEAR | -0.220 | 0.214 | 1.030 | 0.303 |
Graminoids Treatment significance plot
Forbs
Forbs (Selected models)
| (Intercept) | I((YEAR - 1)^2) | I(abs(YEAR - 1)) | aspect | Elevation | InitialHabitat | slope | Treatment:YEAR | R2m | R2c | AICc | delta | weight |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -2.84 | 0.55 | NA | NA | NA |
|
NA |
|
0.89 | 0.89 | 163.81 | 0.00 | 0.21 |
| -2.46 | 0.55 | NA | NA | -0.02 |
|
NA |
|
0.81 | 0.81 | 164.01 | 0.20 | 0.19 |
| -2.37 | 1.07 | -1.04 | NA | NA |
|
NA |
|
0.89 | 0.89 | 165.37 | 1.56 | 0.09 |
| -3.23 | NA | 0.89 | NA | NA |
|
NA |
|
0.85 | 0.85 | 165.45 | 1.64 | 0.09 |
| -2.79 | 0.56 | NA | 0 | -0.02 |
|
NA |
|
0.51 | 0.51 | 165.48 | 1.67 | 0.09 |
| -3.16 | 0.55 | NA | 0 | NA |
|
NA |
|
0.49 | 0.49 | 165.49 | 1.68 | 0.09 |
| -2.00 | 1.08 | -1.04 | NA | -0.02 |
|
NA |
|
0.79 | 0.79 | 165.58 | 1.77 | 0.08 |
| -2.66 | 0.55 | NA | NA | NA |
|
-0.02 |
|
0.89 | 0.89 | 165.66 | 1.85 | 0.08 |
| -2.86 | NA | 0.89 | NA | -0.02 |
|
NA |
|
0.81 | 0.81 | 165.66 | 1.85 | 0.08 |
Forbs (Response plot)
Forbs Treatment significance
| term | estimate | std.error | statistic | p.value |
|---|---|---|---|---|
| TreatmentPermanentExclosure:YEAR | -0.221 | 0.400 | 0.552 | 0.581 |
| TreatmentControl:YEAR | -0.681 | 0.505 | 1.347 | 0.178 |
| TreatmentMowing:YEAR | -0.447 | 0.511 | 0.875 | 0.382 |
| TreatmentSummerExclosure:YEAR | -0.110 | 0.405 | 0.271 | 0.786 |
| TreatmentWinterExclosure:YEAR | -0.404 | 0.439 | 0.919 | 0.358 |
Forbs Treatment significance plot
Discussion
- Most patterns make sense with what is expected
- Drought has a very large effect on most measures
- Test of Beta diversity change spatially and over time
- Check lidar over time to see changes
- Soil measures instead of initial habitat classes