Abstract Native to Asia, the spotted lanternfly, Lycorma delicatula (White), is an emerging pest of many commercially important plants in Korea, Japan, and the United States. Determining its potential distribution is important for proactive measures to protect commercially important commodities. The objective of this study was to assess the establishment risk of L. delicatula globally and in the United States using the ecological niche model MAXENT, with a focus on Washington State (WA), where large fruit industries exist. The MAXENT model predicted highly suitable areas for L. delicatula in Asia, Oceania, South America, North America, Africa, and Europe, but also predicted that tropical habitats are not suitable for its establishment, contrary to published information. Within the United States, the MAXENT model predicted that L. delicatula can establish in most of New England and the mid-Atlantic states, the central United States and the Pacific Coast states, including WA. If introduced, L. delicatula is likely to establish in fruit-growing regions of the Pacific Northwest. The most important environmental variables for predicting the potential distribution of L. delicatula were mean temperature of driest quarter, elevation, degree-days with a lower developmental threshold value of 11°C, isothermality, and precipitation of coldest quarter. Results of this study can be used by regulatory agencies to guide L. delicatula surveys and prioritize management interventions for this pest.
National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211), current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2) and at a fine spatial resolution (90 m) is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum.
Luizza, M. W., T. Wakie, P. H. Evangelista, and C. S. Jarnevich. 2016. Integrating local pastoral knowledge, participatory mapping, and species distribution modeling for risk assessment of invasive rubber vine (Cryptostegia grandiflora) in Ethiopia's Afar region. Ecology and Society 21(1):22.http://dx.doi.org/10.5751/ES-07988-210122
Agricultural systems are enormously variable in space and time. New and developing artificial intelligence (AI)-based tools can leverage site-based science and big data to help farmers and land managers make site-specific decisions. These tools are improving information about soils and vegetation that forms the basis for investments in management actions, provides early warning of pest and disease outbreaks, and facilitates the selection of sustainable cropland management practices. Continued progress with AI will require more observational data across a wide range of agricultural settings, over long time periods.
The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is a highly destructive pest of cherries (Prunus spp.) (Rosaceae) in Europe and Asia. In 2016, R. cerasi was detected in Ontario, Canada, and in 2017 in New York State, USA, the first records of this pest in North America. The initial detections in Canada caused concern for the major cherry-growing states of Michigan, Washington, Oregon, and California in the United States. Establishment of R. cerasi in the United States could restrict cherry exports to other markets and increase costs needed for fly control, but it is unknown if R. cerasi can establish in U.S. commercial cherry regions. Here, we used the CLIMEX ecological niche model to determine the risk of establishment of R. cerasi in the United States and globally. Within the United States under a no-irrigation scenario, R. cerasi would establish in the East and West Coasts; however, under an irrigation scenario, its distribution would expand to the major cherry-growing regions in the interior of central and eastern Washington and in California. Results also showed that if introduced, R. cerasi would likely establish in eastern China, Japan, the Koreas, Australia, New Zealand, South America, South Africa, Mexico, and Canada. Host plant (Prunus spp. and Lonicera spp. [Caprifoliaceae]) presence, although not included in models, would affect fly establishment. Our results stress the importance of surveying for R. cerasi to prevent its spread and establishment within the United States and other countries.
We used correlative models with species occurrence points, Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation indices, and topo-climatic predictors to map the current distribution and potential habitat of invasive Prosopis juliflora in Afar, Ethiopia. Time-series of MODIS Enhanced Vegetation Indices (EVI) and Normalized Difference Vegetation Indices (NDVI) with 250 m2 spatial resolution were selected as remote sensing predictors for mapping distributions, while WorldClim bioclimatic products and generated topographic variables from the Shuttle Radar Topography Mission product (SRTM) were used to predict potential infestations. We ran Maxent models using non-correlated variables and the 143 species- occurrence points. Maxent generated probability surfaces were converted into binary maps using the 10-percentile logistic threshold values. Performances of models were evaluated using area under the receiver-operating characteristic (ROC) curve (AUC). Our results indicate that the extent of P. juliflora invasion is approximately 3,605 km2 in the Afar region (AUC = 0.94), while the potential habitat for future infestations is 5,024 km2 (AUC = 0.95). Our analyses demonstrate that time-series of MODIS vegetation indices and species occurrence points can be used with Maxent modeling software to map the current distribution of P. juliflora, while topo-climatic variables are good predictors of potential habitat in Ethiopia. Our results can quantify current and future infestations, and inform management and policy decisions for containing P. juliflora. Our methods can also be replicated for managing invasive species in other East African countries.
The oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), is a primary pest of stone fruits that cause significant economic damage. Larvae, which enter the host plant through shoot tips, damage shoots, and ripe fruits. Native to Asia, this pest now occurs in many fruit-growing countries, including the United States and Canada. Though the pest was previously reported from many states within the United States, its current distribution and the environmental variables that influence its distribution are not properly identified. The objectives of this study were to 1) identify the environmental factors associated with G. molesta current distribution, 2) predict the current distribution of G. molesta in Washington State (WA) using Maxent and Climex models, 3) identify those areas within WA best suited for establishment of pest free zones, areas of low pest prevalence, and pest free production areas, and 4) identify regions most at risk for further expansion of G. molesta populations as a function of climate change. The current models predicted a small portion of central WA is suitable to support G. molesta, which is consistent with observed distributions. However, climate change models predict that more areas will become suitable for the pest. These results indicate that action should be taken to monitor and reduce current populations of G. molesta to stem its potential expansion into the major commercial tree fruit production areas in the state.
Abstract Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a serious pest of apple (Malus domestica [Borkh.]), pear (Pyrus communis [L.]), and occasionally, stone fruit (Prunus persica [L.]). Its presence in sweet cherries is rare and presumed to occur in areas where high populations in pome fruits occur near sweet cherries, Prunus avium (L.). Nevertheless, the potential of codling moth residing in a sweet cherry destined for an export market, especially to Asian Pacific countries, has led to the continued use of methyl bromide, an ozone-depleting fumigant, to prevent the accidental spread of this pest. Over the past 20 yr, internationally accepted alternative phytosanitary treatments using ionizing radiation have been developed. This is the first report of an irradiation dose response of codling moth in sweet cherries. We treated the first three instars of codling moth in export-quality sweet cherries and found that the third instar was the most radio-resistant, requiring a dose of approximately 250 Gy to prevent adult emergence. This dose is higher than those reported for fifth-instar codling moth in apples and artificial diet but should not delay any efforts in using this highly effective treatment to meet quarantine restrictions against this pest.
