Decadal trends in marine reserves reveal differential rates of change in direct and indirect effects

Decadal-scale observations of marine reserves suggest that indirect effects on taxa that occur through cascading trophic interactions take longer to develop than direct effects on target species. Combining and analyzing a unique set of long-term time series of ecologic data in and out of fisheries closures from disparate regions, we found that the time to initial detection of direct effects on target species (±SE) was 5.13 ± 1.9 years, whereas initial detection of indirect effects on other taxa, which were often trait mediated, took significantly longer (13.1 ± 2.0 years). Most target species showed initial direct effects, but their trajectories over time were highly variable. Many target species continued to increase, some leveled off, and others decreased. Decreases were due to natural fluctuations, fishing impacts from outside reserves, or indirect effects from target species at higher trophic levels. The average duration of stable periods for direct effects was 6.2 ± 1.2 years, even in studies of more than 15 years. For indirect effects, stable periods averaged 9.1 ± 1.6 years, although this was not significantly different from direct effects. Populations of directly targeted species were more stable in reserves than in fished areas, suggesting increased ecologic resilience. This is an important benefit of marine reserves with respect to their function as a tool for conservation and restoration

Large-Scale Disturbance and the Structure of Marine Systems: Fishery Impacts on Georges Bank

Georges Bank, a shallow submarine plateau located off the New England coast, has supported valuable commercial fisheries for several centuries. The region is characterized by high levels of primary productivity and, historically, high levels of fish production. Within the last four decades Georges Bank has been subjected to major perturbations that have profoundly altered levels of catch, abundance, and species composition. The arrival of distant water fleets during the early 1960s resulted in dramatic increases in effective fishing effort and the subsequent commercial collapse of several fish populations. Total fish biomass is estimated to have declined by \u3e50% on Georges Bank during the period of operation of the distant water fleets. The implementation of extended jurisdiction (the 200-mile [370.4-km] limit) in 1977 was followed by modernization and increased capacity of the domestic fleet, resulting in a second perturbation to the system that resulted in further declines in groundfish populations to historically low levels. A subsequent increase in the abundance of species of low commercial value was documented, with an apparent replacement of gadid and flounder species by small elasmobranchs (including dogfish sharks and skates). Examination of feeding guild structure suggests that this switch in species dominance may have been linked to a competitive release. The small elasmobranchs, notably dogfish sharks, also prey on species of commercial importance (primarily small pelagics, including herring and mackerel). The cumulative impacts on the groundfish populations as a result of intense exploitation and predation pressure may have been further exacerbated by effects of fishing gear on the physical structure of the habitat. Implications for the development of an ecosystem-based management approach are described

Indoor thermal comfort control based on fuzzy logic

Control and monitoring of indoor thermal conditions represent crucial tasks for people’s satisfaction in working and living spaces. In the first part of the chapter we address thermal comfort issues in a working office scenario. Among all standards released, predicted mean vote (PMV) is the international index adopted to define users thermal comfort conditions in moderate environments. In order to optimize PMV index we designed a novel fuzzy controller suitable for commercial Heating, Ventilating and Air Conditioning (HVAC) systems. However in a residential scenario it would be extremely expensive to gather real time measures for PMV computation. Indeed in the second part of the chapter we introduce a novel approach for residential multi room comfort control based on humidex index. A fuzzy logic controller is introduced to reach and maintain comfort conditions in a living environment. Both control systems have been experimentally tested in the central east coast of Italy. Temperature regulation performances of both approaches have been compared with those of a classical PID based thermostat. © 2016, Springer International Publishing Switzerland 2016