Common garden data

The file contains all data used in the statistical analyses described in the materials and methods section of the article. Abbreviated headlines are as follows: "Pop"=Population; "Code"= number of family associated with the population; "Fam"=family; "Number"=number of each plant within a family; "PB"=plunge bed; "Treatment"=water treatment ("D"=drought stress; "W"= ambient water treatment); "Beetles"=number of beetles; "Aphids_(cm)"=cm covered by aphids; "Aph"=Aphids_(cm)+0.1; "Stem"=number of holes produced by C.quadridens larvae in the plant stem; "Weight"=above-ground biomass (g); "Infl."=number of inflorescences; "Damage"=percent damage by herbivores; "Height_Aft"=plant height

Characteristics of the study species.

<p>Seed morphology, mean falling velocity of painted seeds (10 replicates, in brackets: unpainted seeds) and association to transport corridors of the four study species.</p

Effect of the number of vehicle passes on the shape of the fitted dispersal kernel (Lognormal function).

<p>(A) <i>Ailanthus altissima</i>, (B) <i>Clematis vitalba</i>, (C) <i>Ambrosia artemisiifolia</i>, and (D) <i>Brassica napus</i>. The y-axis is on a log scale and 0.0001 was added to all probabilities to show zero values. Inset tables show parameter estimates (<i>a</i> = scale parameter, <i>b</i> = shape parameter) for the different numbers of vehicle passes.</p

Dispersal distances for the study species after different numbers of vehicle passes.

<p>Note our recapture rates given under ‘results’. Also note that movement along the road decreased considerably for multiple vehicle passes but resulted in increased lateral transport. Dispersal distances might change greatly when dispersal by car's airflow interacts with other forms of dispersal (e.g. wind) transporting seeds back to the driving lane.</p

Probability distributions of seeds along the study road after 80 vehicle passes.

<p>(A) <i>Ailanthus altissima</i> (B) <i>Clematis vitalba</i>, (C) <i>Ambrosia artemisiifolia</i> and (D) <i>Brassica napus</i>. Filled circles represent the mean (±95% CI) probabilities of 10 replicates. The grey lines show the fitted dispersal functions. Open triangles show mean probabilities for seeds to reach the road verge at that distance along the line of travel. The y-axis is on a log scale and 0.0001 was added to all probabilities to show zero values. Note that this is not a total dispersal kernel but solely shows secondary dispersal by car's airflow.</p

Influence of the starting section on parallel and lateral movement of seeds by a passing car.

<p>Dispersal patterns of <i>Ailanthus altissima</i> seeds after one vehicle pass for seeds initially placed in the verge (left panel), the left side (second panel from left) the driving lane (centre panel), the right side (second panel from right) and the opposite lane (right panel). Probabilities of reaching the different sections of the study road are indicated by different grey shading. Probabilities are averaged over 50 replicates.</p

Parameter estimates and AIC for different dispersal functions.

<p>Models were fit to the probability distributions for the four study species after 80 vehicle passes. The model with the lowest AIC for each species is in bold.</p

Lateral movement of seeds of <i>Ailanthus altissima</i> in relation to the number of vehicle passes.

<p>(A) Mean probabilities of seed deposition of <i>Ailanthus altissima</i> in the parallel road sections in relation to the number of vehicle passes. (B) Proportion (±95% CI) of seeds of <i>Ailanthus altissima</i> accumulating at the verge in relation to the number of vehicle passes. At the start of experiment seeds were laid out only on the driving lane.</p

Sections of the study road.

<p>The car remained within the driving lane, making this the section most directly impacted by the passing vehicle. The adjoining sections (left and right) were not driven over, but would have been strongly affected by the vehicle's airflow. Seed settlement is considered to occur in the verge, which provides the most immediate establishment opportunity for seeds. The opposite lane represents the area beyond the midpoint of the lane, where, on a real road, the seed would be in the path of oncoming traffic.</p

Relative value of four different vegetation types, situated along a successional gradient, for biodiversity and provision of ecosystem services.

<p>(a) Biodiversity value, presented as the mean number of records per hectare of species of conservation concern, (b) carbon density, presented as mean values of total (above- and below-ground) carbon storage per unit area (t C ha^-1), (c) aesthetic value, presented as mean preference scores elicited from a visitor survey, and (d) recreational value, presented as the results of a correlation test between the number of heathland visitors and area of vegetation type (n.s., not significant; * P< 0.05, *** P< 0.001; y axis represents correlation coefficient). For (a)-(c), mean values grouped by the same letter are not significantly different (P< 0.05, Mann Whitney U test). For timber value, see text.</p