Data for: Effects of terrestrial transport corridors and associated landscape context on invasion by forest plants

<p>The construction, use, and maintenance of roads and railroads (terrestrial transport corridors, TTCs) facilitate spread of invasive plants, but the distances at which plants spread away from TTCs, and how that process is mediated by landscape context, is not well understood. We analyzed data from 44,000+ forest inventory plots in the eastern USA to investigate how invasive richness, defined as the number of invasive plant species per ~672 m<sup>2</sup> plot, is influenced by distance from the nearest TTC, surrounding land use type, and ecological province using a generalized linear model framework. Invasive richness in forests decreased as distance from the nearest TTC increased. Directly adjacent to TTCs, there were an estimated 1.4 ± 0.01 SE invasive plant species per plot compared to 0.7 ± 0.01 and 0.2 ± 0.01 species at 1 km and 3 km, respectively, away from the nearest TTC. Invasive richness was highest on plots associated with a combination of agriculture/development (2.1 ± 0.03 species per plot) and in the Midwest Broadleaf Forest province (2.1 ± 0.06). Our macroscale analysis also demonstrated that rates of decay in invasive richness away from TTCs was mediated by the types of land use and ecological provinces within which plots were located. The influences of TTCs and associated activities (e.g., construction, travel) on invasive plant richness were widespread across forests of the eastern USA, but the relative importance of TTCs for facilitating spread appear to be highly context dependent.</p>

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