No abstract

Hemlock woolly adelgid (Adelges tsugae Annand) (HWA) is an invasive forest insect sweeping across the native range of eastern (Tsuga canadensis [L.] Carr.) and Carolina (Tsuga caroliniana Engelm.) hemlocks, threatening to severely reduce eastern hemlock extent and to push Carolina hemlock to extirpation. HWA poses a significant threat to these eastern US natives, now infesting hemlocks across 19 states and more than 400 counties. For the long-term preservation of the species, ex situ genetic resource conservation efforts such as seed collection, storage, and adelgid-resistant hemlock breeding may all be necessary. To ensure the efficient and effective application of these efforts, it will be necessary to prioritize locations within the native ranges, because it is logistically impossible to apply these efforts to all populations. To build upon 12 years of seed banking for eastern and Carolina hemlock, we applied a novel approach for incorporating multiple dissimilar data sets into a geographic prioritization of areas for the most effective and efficient conservation of genetic diversity. The approach involves integration of geographic information systems with the multi-attribute frontier mapping technique to Electronic supplementary material The online version of this article (identify locations across the ranges of these two imperiled species most in need of conservation actions. Specifically, our assessment incorporated four genetic diversity parameters, a climate component, a measure of population disjunctiveness, a measure of local hemlock abundance, and seed collection density to prioritize areas of eastern and Carolina hemlock occurrence for ex situ gene conservation. For each species, the result was a mapped index of locations prioritized by the combined significance of these factors. For eastern hemlock, this assessment assigned the highest priority to disjunct populations and to some areas within the main-body range. With Carolina hemlock, disjunct northern populations and central main-body locations received the highest prioritization. Our prioritization approach could be applied similarly to other species facing pressure from invasive pests or other environmental threats.

Solid wood packaging material (WPM) is widely recognized as a high-risk pathway for transport and potential introduction of wood-boring insects, including longhorned beetles in the family Cerambycidae. These beetles also are occasionally imported in finished wood products, such as furniture and decorative items. A targeted effort to identify wood borers intercepted as larvae in WPM at U.S. ports between 2012 and 2018 revealed that one of the most frequently intercepted species was Trichoferus campestris (Faldermann), a cerambycid native to Asia. Trichoferus campestris is a pest of quarantine concern in the United States, Canada, and Europe. The establishment risk of this beetle in the United States is high because of its frequent introduction through multiple pathways and its potential to inhabit natural and urban forests as well as agricultural systems. In this study, we compiled port interception and detection data to examine risk based on historical introductions and pathways. We tested whether the intended destination of cargo intercepted with T. campestris-infested WPM can be used as a predictor of inland introductions, assuming that individuals of T. campestris are likely to be moved through established trade routes between export–import partners. We also developed maps to predict likely areas of introduction and establishment in the United States based on pathway analysis and climate suitability data. The maps will enable informed prioritization of resources in pest surveillance, and may serve as models for other wood borers identified in the WPM and wood products pathway.

CLIMEX and MED-FOES models integrate climate and data on Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), biology and use it to define the environmental suitability for the pest at specific geographical locations. CLIMEX calculates growth indices as indicators of conditions that are suitable for medfly population growth. MED-FOES incorporates additional information on pest management interventions to simulate the process and timing of medfly eradication. CLIMEX simulations of climatic suitability in California and Florida indicated that the most favorable periods for medfly population growth are March through May and October through November, whereas the environment would be especially stressful during the summer months, except when irrigation is applied. With irrigation, California is highly suitable for medfly population growth during the summer months. Due to cool temperatures, medfly populations are likely to decline significantly in January through February in Los Angeles, Tampa, and Miami, and probably not survive in San Francisco. According to MED-FOES simulations, it possibly would take longer to eradicate medfly from California than Florida, particularly if the incursions are initiated in the summer months. Medfly annual growth indices for the ENSO La Niña years are relatively low for San Francisco and Los Angeles but above neutral for Tampa and very high for Miami. During the El Niño phase, the growth index remains unchanged for San Francisco, increases for Los Angeles, and decreases for Tampa and Miami. CLIMEX and MED-FOES models are useful for informing plans to manage invasion threats from medfly and other invasive insects.