Contents lists available at ScienceDirect Remote Sensing Applications: Society and Environment journal homepage: www.elsevier.com/locate/rsase Monitoring and predicting the potential distribution of alien plant species in arid ecosystem using remotely-sensed data Marwa Waseem A. Halmy a, ⁎ , Manal Fawzy a , Dalia A. Ahmed b , Nouran M. Saeed a , Mohamed A. Awad a a Department of Environmental Sciences, Faculty of Science, Alexandria University, Alexandria, Egypt b Botany Department, Faculty of Science, Tanta University, Tanta, Egypt ARTICLE INFO Keywords: Invasion Maxent Predictive species modeling Desert Spectral indices ABSTRACT Human activities cause introduction of alien species to new areas, which may cause serious problems and threats to biodiversity and ecosystem services. Omayed biosphere reserve (OBR) at the northwestern desert of Egypt, recognized for its rich flora, has recently encountered new human-induced disturbances. The current study sought to identify alien species that might have invaded OBR as a result of such activities; and to estimate the area affected by alien species using remotely-sensed data. Field surveys of 300 sampling plots representing different habitats were conducted from spring 2011 to spring 2014, whereby occurrences of alien plant species were recorded. We evaluated the use of combined environmental and remotely-sensed data for developing predictive distribution models for 21 alien species recorded in the area using Maxent modeling technique. The inclusion spectral predictors with other environmental predictors has improved the performance of the dis- tribution models (mean test AUC 0.88 ± 0.06) for most of the alien species. Environmental variables that contributed the most to prediction of alien species distribution included soil, elevation and slope; in addition to predictors that represented disturbance proxies such as distance from irrigation canals and distance from roads. The results revealed that more than 40% of the area is predicted to be infested by at least one alien species. Results also manifest the merit of incorporating remotely-sensed data in prediction of alien species distribution, which hold promise for development of proactive management approaches to identify and control areas of high infestation of alien species and prevent further spread of invasive plants. 1. Introduction Alien plants species are species that are introduced due to human activities to new areas in which they get established, flourish then spread causing socioeconomic consequences and negatively impact ecosystems (Vitousek et al., 1997). Infestation by non-indigenous and alien plant species are causing major problems in many regions worldwide and are viewed as an important component of human- caused global change (Vitousek et al., 1997; Nigatu and Sharma, 2013). Generally, the spread of invasive species is associated with the dis- turbance caused by human activities associated with expansion of croplands, road networks construction, and urbanization (Roy, 1990; Vilà et al., 1999). Alien invasive species are one of the main threats to the existence and conservation of native species (Ehrenfeld, 2010; Duncan et al., 2013). The expansion of invasive alien plant can lead to biodiversity impoverishment (Huston, 1994), reduce yields from agri- culture, reduce water availability, contribute to land degradation, block transport routes, and facilitate spread of disease (Nigatu and Sharma, 2013) and can alter disturbance regimes (D’Antonio and Vitousek, 1992). Moreover, alien species can have significant socioeconomic impact through negatively influencing the provisioning of natural ecosystems services in the affected areas, thus, contributing to the social instability and economic hardship, restraining sustainable development and economic growth (McNeely et al., 2001). A thorough understanding of the invasion process is needed to avert the threats posed by invasive species (Roy, 1990). Any attempts to avoid invasions or to control established invasive species need to be based on comprehensive knowledge on the ecology of the alien species and the characteristics of habitats and their susceptibility to invasion (D’Antonio and Vitousek, 1992; Vitousek et al., 1997). Remote sensing techniques can contribute to the efforts aimed at controlling and avoiding invasions by providing approaches for accurately mapping actual distribution of alien species, in addition to the possibility of ef- ficiently predicting regions at potential risk of invasion (Rocchini et al., https://doi.org/10.1016/j.rsase.2018.10.005 Received 1 February 2018; Received in revised form 1 July 2018; Accepted 18 October 2018 ⁎ Correspondence to: Department of Environmental Sciences, Faculty of Science, P.O. Box: 21511, Alexandria, Egypt. E-mail address: marwa.w.halmy@alexu.edu.eg (M.W.A. Halmy). Remote Sensing Applications: Society and Environment 13 (2019) 69–84 Available online 26 October 2018 2352-9385/ © 2018 Elsevier B.V. All rights reserved. T