People are now driving the sixth mass extinction in Earth’s history, and yet biodiversity enhances many of nature’s benefits to people. The influence and dependence of people on biodiversity have mainly been studied separately and at contrasting scales of space and time but new ecological theory is beginning to link these relationships across scales. This theory shows that biodiversity loss substantially diminishes many ecosystem services by altering ecosystem functioning and stability especially at the large temporal and spatial scales that are most relevant for policy and conservation. The influence and dependence of people on biodiversity also generate an important if poorly understood feedback loop between humans and nature. New models of social-ecological systems emphasize the role of feedbacks and scales in human-nature interactions and the importance of foresight for the sustainability of human societies. They call for the development of integrative management approaches that account for the coupled dynamics of human populations biodiversity and ecosystems across multiple spatial and temporal scales.

     Speciation is a continuous process and analysis of species pairs at, "different stages of divergence provides insight into how it unfolds. Spanning the speciation continuum stickleback species pairs are ideal for investigating how genomic divergence builds up during speciation. However attention has largely focused on young postglacial species pairs with little known of the genomic signatures of divergence and introgression in older systems. The Japanese stickleback species pair Gasterosteus aculeatusG. nipponicus which co-occur in the Japanese islands is at a late stage of speciation. Here we use coalescent analyses and Approximate Bayesian computation to show that the two species split approximately 0.68-1 million years ago but that they have continued to hybridise at a low rate throughout divergence. Population genomic data revealed that high levels of genomic differentiation are maintained across the majority of the genome when gene flow occurs. However despite this we identified multiple small regions of introgression strongly correlated with recombination rate. Our results demonstrate that a high level of genome-wide divergence can establish in the face of persistent introgression and that gene flow can be localized to small genomic regions at the later stages of speciation with gene flow, composed of the Pacific Ocean three-spined stickleback and the Japan Sea stickleback.

     Wide-spreading of antibiotic resistance is one of the most important issues in not only public health but also a huge economic burden. Dissemination of multidrug resistance (MDR) gene(s) resulted in emergence of MDR bacteria, or casually called “superbugs”. These transmissions were often carried out by conjugative plasmids that also encode genes sufficient for a means of horizontal gene transfer, namely conjugation which is carried out by cell-to-cell contact. We are interested in dynamics of dissemination of MDR conjugative plasmid, using pESBL as our model plasmid. This plasmid was originally identified in Escherichia coli O104 outbreak strain in Germany in 2011, and participated the severity of outbreak as it provided MDR phenotype to the host cells.
     Taking advantage of Transposon insertion site sequencing (Tnseq), a recently developed technique which allows the high-throughput quantitative fitness assessment of individual genomic loci, we identified genes involved in the conjugative transfer of pESBL. Surprisingly, Tnseq also unveiled a small regulatory region in pESBL: mutations in this region result in highly elevated transfer efficiency of the plasmid. This and other lines of evidence indicate that single mutations can create plasmids with substantially increased ability to spread, threatening emergence of ’superspreader’ mutants.
     Transferred plasmid molecule has to be established in the recipient cell for the completion of the conjugative DNA transfer. I will also discuss our recent studies on various factors involved in this establishment, such as plasmid partitioning and a system counteracting host immunity.