Contrasting population genetic structures of sympatric, mass-spawning Caribbean corals

Coral reef conservation management policy often focuses on larval retention and recruitment of marine fish with scant data available on important, less motile reef-building species such as corals. To evaluate the concept of population connectivity in corals, we tested whether broadcast spawning reproduction per se confers the same degree of dispersal to two sister species, Montastraea annularis (Anthozoa: Scleractinia; Ellis and Solander 1786) and M. faveolata (Ellis and Solander 1786), both dominant taxa in reefs of the northern Caribbean. Genetic analyses of ten nuclear DNA loci (seven microsatellite and three single-copy RFLP) reveal strikingly different patterns of population genetic subdivision for these closely related, sympatric species, in spite of likely identical dispersal abilities. Strong population genetic structure typified the architecture of M. annularis, whereas M. faveolata populations were principally genetically well mixed. A higher level of clonality was observed in M. annularis potentially because of a susceptibility to physical fragmentation. Clonality did not, however, significantly contribute to population genetic structure or low-level Hardy–Weinberg and linkage disequilibria observed in some populations. The lack of consistent association between reproductive mode and dispersal reinforces the perspective that population connectivity is not so much a function of predictable marine population source and sink relationships as is due to a more complex interface of oceanic currents interacting with and amplifying stochastic fluctuations in larval supply and settlement success. Our results support others promoting an overall ecosystem approach in marine protected area design.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Policy roots of land degradation in the arid region of the United States: An overview

The roots of land degradation in the arid region of the United States are set firmly in the era of open range conditions that led to the depletion of rangeland resources in the late 19th and early 20th centuries. Upon closure of the open range and establishment of the U.S. Forest Service and the Bureau of Land Management, public lands in the arid region were protected from the classic tragedy of the commons. Private lands, in turn, fell under the stewardship guidance of such organizations as the Soil Conservation Service, the Agricultural Stabilization and Conservation Service, and the Cooperative Extension Service. Despite these institutional protections, arid land degradation continues at an ecologically and socially unacceptable rate. The most likely explanation for this degradation resides in the institutions and public policies that shape and control livestock grazing. Flaws and disincentives endemic to the grazing permit system have encouraged destructive grazing. Federal subsidies to public- and private-land ranchers have encouraged rangeland stocking rates in excess of carrying capacity on economically and ecologically marginal lands and consistently favored unsound land management practices over superior ones. Policy-generated distortions of market forces have lead to unanticipated and environmentally undesirable land use outcomes. Land management, technical support, and educational institutions have also inadvertently contributed to land degradation in the arid region. Reversing the trend of land degradation in an advanced country like the United States demands that we understand the role of public policy in land use outcomes and that we structure future public policies in accordance with the lessons of recent history.     

Testing individual capability to lift material: Repeatability of a dynamic test compared with static testing

This paper describes a new dynamic testing procedure of individual lift capability and its laboratory evaluation with 39 subjects. In test-retesting, the isoinertial “LIFTEST” proved to be less variable than standard isometric lift tests.