Spatial patterns of female Ailanthus altissima across an urban-to-rural land use gradient

Abstract

Ailanthus altissima is an invasive, dioecious deciduous tree common at the interface between urban and rural areas in the mid-Atlantic region, U.S.A. To examine spatial patterns of abundance and associations with land use type, we mapped all mature female trees in nine 89.5 ha plots (805.5 ha total area) across a typical urban-to-rural land use gradient using aerial images obtained via remote sensing supplemented by detailed ground referencing. Rural plots were dominated by forest and had the lowest density of mature females (0.007 females ha −1 ); urban and suburban plots did not differ significantly in mean density (0.37 females ha −1 vs. 0.34 females ha −1 , respectively). Individuals in urban plots were more evenly distributed, but were not associated with a wider variety of land uses and were closer to roads or openings than those in suburban plots. Given less available habitat per unit area in urban than in suburban environments, these patterns suggest that Ailanthus fits the profile of an invasive species that may be proliferating outward from urban centers. With continued disturbances associated with development in the suburban areas, and timber harvesting in the rural areas, further spread of Ailanthus seems likely.

Citizen Science as a Tool in Biological Recording—A Case Study of Ailanthus altissima (Mill.) Swingle

“…Tree of heaven (Ailanthus altissima) is one of today's most invasive plant species, present on all continents except Antarctica [19][20][21], preferring urban and highly localised disturbed areas [1]. It was introduced from China to Europe (Paris) in the 1740s primarily as an ornamental tree [22].…”

“…Invasive species biological recording, mapping, and monitoring are prerequisites for successful biological invasion risk management [31][32][33] and to prevent invasive species expansion into large areas, where eradication becomes very difficult and costly [1]. Among invasive plants, trees are generally easiest to map because of their size [34], although there is currently no methodical, reasonably priced protocol for the estimation of tree invasions that can be used in invasive species management or scientific research [35].…”

“…Conducting invasive plant inventories is a critical component of an integrated approach to invasive plant management [26]. One of the first, crucial steps in an effective management strategy is the estimation of invasive species abundance and distribution [1]. Inventory data often provide the information necessary to evaluate the extent of plant invasion, allowing land managers to prioritise management efforts; however, these data are often expensive to collect [36].…”

“…Scientists have devoted significant energy to determining the principles of alien species invasions [1]. Alien species invasion is recognised as one of the most severe and demanding global environmental threats [2].…”

Fine-scale initiation of non-native Robinia pseudoacacia riparian forests along the Chikumagawa River in central Japan

“…To address this issue, it is essential to understand how the propagules of such species disperse from the parent plants. While an accurate history of the expansion of a naturalized species is difficult to obtain, the radiation of some invasive plants has been demonstrated through historical records of naturalization assimilated via landscape-scale analyses (Landenberger et al 2009) and population-genetic analysis (Bossdorf et al 2005, Rosenthal et al 2008, Sakio 2009, Pairon et al 2010. For example, landscape-scale information, such as aerial are known to be effective for analyzing the reproductive mechanisms of many organisms, ranging from fungi to higher plants and animals.…”