Figure 1.
Map of the distribution of Mediterranean sclerophyllous woodlands and shrublands and planted pine forest in the study area.
The distribution of forests and woodlands and all sampled sites (stars) is shown on the entire map of the Mediterranean region of Israel (A), with a zoom into the area of the Judean Mountains (B). The immediate landscape buffers (black circles) mark a 500 m radius area surrounding each plot. Other land covers (e.g., infrastructure, agriculture, meadows, urban) are not shown (white areas in the figure).
Table 1.
Model comparison.
Table 2.
Set of maximum likelihood estimated (MLE) parameters and parameter support intervals for the most parsimonious models.
Figure 2.
Sources of Pinus halepensis propagule pressure.
The proportion of regional and landscape components of the propagule pressure from the total propagule pressure as calculated by the most parsimonious model for all 470 sampled plots, as a function of the density of pine seed sources in the 500(m2 cover). Proportion of the regional propagule pressure is shown in open circles and a dashed (declining) line, and landscape propagule pressure is shown in filled circles and a black solid (increasing) line (n = 470). Best fitted lines are exponential 3 parameter functions (p<0.0001).
Figure 3.
Predicted functional forms of the components of the most parsimonious pine colonization model.
(A) Exponential distance dependent decay of landscape propagule input (proportion of seed input per plot relative to maximum input from a seed source stand at distance = 0) as a function of distance from the pine seed source. (B) Predominant seed dispersal directions. Potential colonization as a function of the effects of local resistance factors including: (C) Bedrock type (parameter ± 2-unit support intervals), (D) Gaussian effect of mean annual precipitation, (E) Grazing regime (parameter ± 2-unit support intervals), and (F) Mediterranean woody vegetation cover. The potential colonization as a function of resistance factors is the relative effect by which each factor scales (decreases) the propagule pressure (ranging from 0–1).
Figure 4.
Maps of expected Pinus halepensis colonization.
Map of the expected distribution of densities of pine colonists (trees ha−1) (A), calculated for each location in the Mediterranean region of Israel based on the predictions of the most parsimonious model for: (B) propagule pressure (number of propagules per 200 m2 plot) – as a function of the regional propagule input and the distance-dependent input from pine seed sources in the landscape; and (C) potential colonization – calculated by the combined effects of local habitat factors (soil type, precipitation, grazing and woody vegetation cover). White areas in the map are outside the scope of the analysis (developed or agricultural land or different soil type).