Understory vegetation of boreal tree plantations: Differences in relation to previous land use and natural forests     

Sophie Gachet  Alain Leduc  Yves Bergeron  Thuy Nguyen-Xuan  Francine Tremblay 《Forest Ecology and Management》2007

The aim of this study was to evaluate if and how the previous land use (here: agriculture versus forest) has influenced the floristic composition now observed in the understory of jack pine plantations of Abitibi-Temiscamingue (North-Eastern Canada). Floristic inventories were conducted in jack pine plantations which had been established on forest sites after logging and on sites previously utilized for agriculture. These were compared to one another and to inventories conducted in natural forests and on agricultural sites which had not (not yet) been planted with trees (old fields). The vegetation community composition of the sites is analysed using several multivariate techniques. Results show that the flora of plantations on old agricultural fields is markedly different than that of plantations established on sites which were previously forested and that the two types of plantation are unlikely to become floristically the same before the anticipated harvest time. Comparing old and young plantations and old fields in light of natural forests sites, we show that the previous land-use is a key determinant of future compositional differences in plantations. This must be considered when we evaluate the impact of establishing plantations on sites with different land-use histories.  相似文献   

Preventing invasions of Asian longhorn beetle and citrus longhorn beetle: are we on the right track?     

Branco  Sofia  Faccoli  Massimo  Brockerhoff  Eckehard G.  Roux  Géraldine  Jactel  Hervé  Desneux  Nicolas  Gachet  Emmanuel  Mouttet  Raphaelle  Streito  Jean-Claude  Branco  Manuela 《Journal of pest science》2022,95(1):41-66

Two Asian longhorn beetles, Anoplophora glabripennis and Anoplophora chinensis, are among the most serious alien invasive species attacking forest and urban trees, both in North America and Europe. Major efforts have been put into preventing further entry and establishment of the two species as well as promoting their successful eradication. Here, we review these efforts, their progress and outcome, and scientific advancements in monitoring and control methods. The combined international activities and harmonizing legislative changes in detection and eradication methods have proven worthwhile, with more than 45% of eradication programmes successful in the last 12 years. Some countries were able to completely eradicate all populations and others managed to reduce the area affected. Although the costs of the eradication programmes can be very high, the benefits outweigh inaction. Attempts to eradicate A. chinensis have been more challenging in comparison with those targeting A. glabripennis. For both species, efforts are hampered by the ongoing arrival of new beetles, both from their native regions in Asia and from other invaded regions via bridgehead effects. The methods used for eradication have not changed much during the last decade, and host removal is still the method most commonly used. On the other hand, detection methods have diversified during the last decade with advances in semiochemical research and use of detection dogs. The next decade will determine if eradications continue to be successful, particularly in the case of A. chinensis, which has been targeted in some countries for containment instead of eradication.

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Platelet-derived serotonin mediates liver regeneration     

Lesurtel M  Graf R  Aleil B  Walther DJ  Tian Y  Jochum W  Gachet C  Bader M  Clavien PA 《Science (New York, N.Y.)》2006,312(5770):104-107

The liver can regenerate its volume after major tissue loss. In a mouse model of liver regeneration, thrombocytopenia, or impaired platelet activity resulted in the failure to initiate cellular proliferation in the liver. Platelets are major carriers of serotonin in the blood. In thrombocytopenic mice, a serotonin agonist reconstituted liver proliferation. The expression of 5-HT2A and 2B subtype serotonin receptors in the liver increased after hepatectomy. Antagonists of 5-HT2A and 2B receptors inhibited liver regeneration. Liver regeneration was also blunted in mice lacking tryptophan hydroxylase 1, which is the rate-limiting enzyme for the synthesis of peripheral serotonin. This failure of regeneration was rescued by reloading serotonin-free platelets with a serotonin precursor molecule. These results suggest that platelet-derived serotonin is involved in the initiation of liver regeneration.  相似文献