EXCHANGE INTERACTIONS IN THE QUASI-LINEAR-CHAIN ANTIFERROMAGNET KFES2

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Recent emergence and worldwide spread of the red tomato spider mite, [i]Tetranychus evansi[/i]: genetic variation and multiple cryptic invasions

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699Plant biosecurity is increasingly challenged by emerging crop pests. The spider mite Tetranychus evansi has recently emerged as a new threat to solanaceous crops in Africa and the Mediterranean basin, with invasions characterized by a high reproductive output and an ability to withstand a wide range of temperatures. Mitochondrial (868 bp of COI) and nuclear (1,137 bp of ITS) loci were analyzed in T. evansi samples spanning the current geographical distribution to study the earliest stages of the invasive process. The two sets of markers separate the samples into two main clades that are only present together in South America and Southern Europe. The highest COI diversity was found in South America, consistent with the hypothesis of a South American origin of T. evansi. Among the invaded areas, the Mediterranean region displayed a high level of genetic diversity similar to that present in South America, that is likely the result of multiple colonization events. The invasions of Africa and Asia by T. evansi are characterized by a low genetic variation associated with distinct introductions. Genetic data demonstrate two different patterns of invasions: (1) populations in the Mediterranean basin that are a result of multiple cryptic introductions and (2) emerging invasions of Africa and Asia, each likely the result of propagules from one or limited sources. The recent invasions of T. evansi illustrate not only the importance of human activities in the spread of agricultural pests, but also the limits of international quarantine procedures, particularly for cryptic invasion

Mapping native and non-native vegetation in the Brazilian Cerrado using freely available satellite products

This is the final version. Available on open access from Nature Research via the DOI in this recordNative vegetation across the Brazilian Cerrado is highly heterogeneous and biodiverse and provides important ecosystem services, including carbon and water balance regulation, however, land-use changes have been extensive. Conservation and restoration of native vegetation is essential and could be facilitated by detailed landcover maps. Here, across a large case study region in Goiás State, Brazil (1.1 Mha), we produced physiognomy level maps of native vegetation (n = 8) and other landcover types (n = 5). Seven different classification schemes using different combinations of input satellite imagery were used, with a Random Forest classifier and 2-stage approach implemented within Google Earth Engine. Overall classification accuracies ranged from 88.6-92.6% for native and non-native vegetation at the formation level (stage-1), and 70.7-77.9% for native vegetation at the physiognomy level (stage-2), across the seven different classifications schemes. The differences in classification accuracy resulting from varying the input imagery combination and quality control procedures used were small. However, a combination of seasonal Sentinel-1 (C-band synthetic aperture radar) and Sentinel-2 (surface reflectance) imagery resulted in the most accurate classification at a spatial resolution of 20 m. Classification accuracies when using Landsat-8 imagery were marginally lower, but still reasonable. Quality control procedures that account for vegetation burning when selecting vegetation reference data may also improve classification accuracy for some native vegetation types. Detailed landcover maps, produced using freely available satellite imagery and upscalable techniques, will be important tools for understanding vegetation functioning at the landscape scale and for implementing restoration projects.ShellFAPESPNatural Environment Research Council (NERC