Table 1 Descriptions and expected direction of occurrence probability (ѱ) models for Megathyrsus maximus [M], Leucaena leucocephala [L], and Uniola virgata [U] along the 570-m bulldozed trail in the Ensenada sector of the Guánica Forest. All models tested for significance at α = 0.05
Hypothesis | Model | Structure of model | Expected results |
|---|---|---|---|
1. [All]: no influence of any factor over species | ѱ (.) | β 0 | – |
2. [M, L]: negative influence of trail distance from road | ѱ (Dist_z) | β 0 + β 1 (Dist_z) | β 1 < 0 |
[U]: positive influence of trail distance from road | ѱ (Dist_z) | β 0 + β 1 (Dist_z) | β 1 > 0 |
3. [All]: positive influence of distance and temporal patterns | ѱ (Time) | β 0 + β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) | β 1 < 0, β 2 < 0, β 3 > 0, β 4 > 0 |
4. [M]: negative influence of U. virgata and L. leucocephala presence | ѱ (NatColo) | β 0 + β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (U. virgata and L. leucocephala) | β 1 < 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0 |
5. [U]: negative influence of M. maximus and L. leucocephala presence | ѱ (InvColo) | β 0 + β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (M. maximus and L. leucocephala) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0 |
6. [L]: negative influence of M. maximus and U. virgata presence | ѱ (GrassColo) | β 0 + β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (M. maximus and U. virgata) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 > 0 |
7. [All]: negative influence of the presence of native trees and other vegetation | ѱ (NatVeg) | β 0 + β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (other vegetation) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0 |
8. [M]: negative influence of all effects on M. maximus presence | ѱ (AllColoNat) | β 0+ β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (U. virgata and L. leucocephala) + β 6 (other vegetation) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0, β 6 < 0 |
9. [U]: negative influence of all effects on U. virgata presence | ѱ (AllColoInv) | β 0+ β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (M. maximus and L. leucocephala) + β 6 (other vegetation) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0, β 6 < 0 |
10. [L]: negative influence of all effects on L. leucocephala presence | ѱ (AllColoGrass) | β 0+ β 1 (Dist_z) + β 2 (July 2012) + β 3 (December 2012) + β 4 (July 2013) + β 5 (M. maximus and U. virgata) + β 6 (other vegetation) | β 1 ≤ 0, β 2 < 0, β 3 > 0, β 4 < 0, β 5 < 0, β 6 < 0 |