T his volume contains a variety of chapters about the demonstrated and suspected effects of natural and human-related agents on biodiversity. The effects of human-related agents may be indirect (such as habitat or climate change) or inadvertent—perhaps even the result of well-inten-tioned efforts to preserve biodiversity, such as the isolation of nature preserves or the potential for disturbanc...

Over 100 native herbaceous forest perennials are harvested in the United States. Management of these populations for continued survival requires information on the long-term effects of varied harvesting levels on populations of forest perennials. Allium tricoccum Ait. is a species that is harvested throughout its range for its edible bulb. We examined the recovery of A. tricoccum populations ov...

Turbidity regimes vary dramatically among small streams in north coastal California. In an analysis of turbidity data from 27 small streams in the region, turbidity at the 10-percent exceedence level ranged from 3 to 116 formazin nephelometric units (FNU) for the 2005 wet season, translating to 1.7 to 65 days above an oft-cited biological threshold of 25 FNU. Watersheds draining to the streams ...

A demonstration was conducted to examine the stored forage yield and stored forage quality of two different hay forage management systems. The forage management systems were a hay harvest only system or a complimentary hayround bale silage harvest system. The hay system harvested bermudagrass forage as hay during the summer when weather conditions allowed, the complimentary system harvested ber...

Regulatory efforts to reduce bycatch fulfill multiple management goals -from protecting overfished and depleted species, to preventing over-harvest of species of unknown abundance, to acknowledging that vessels using different gear types require different harvest strategies, to matching within-year harvest rates to within-year abundance and congregation habits of managed species. These goals mu...

Spatial heterogeneity plays an important role in complex ecosystem dynamics, and therefore is also an important consideration in sustainable resource management. However, little is known about how spatial effects can influence management targets derived from a non-spatial harvest model. Here, we extended the Schaefer model, a conventional non-spatial harvest model that is widely used in resourc...

Plant harvest is one of the most important management practices in constructed wetlands. In this study, we evaluated the impact of harvesting Phragmites australis (Cav.) Trin. ex Steudel on the activity and community structure of nitrifiers and denitrifiers in a free-water surface constructed wetland. The nitrifiers were targeted using bacterial and archaeal-amoA that encode ammonia monooxygena...

Populations of small pelagic fish are strongly influenced by climate. The inability of managers to anticipate environment-driven fluctuations in stock productivity or distribution can lead to overfishing and stock collapses, inflexible management regulations inducing shifts in the functional response to human predators, lost opportunities to harvest populations, bankruptcies in the fishing indu...

Forest harvest scheduling has been modeled using deterministic and stochastic programming models. Past models seldom address explicit spatial forest management concerns under the influence of natural disturbances. In this research study, we employ multistage full recourse stochastic programming models to explore the challenges and advantages of building spatial optimization models that account ...

Ecosystem approaches to natural resource management are seen as a way to provide better outcomes for ecosystems and for people, yet the nature and strength of interactions among ecosystem components is usually unknown. Here we characterize the economic benefits of ecological knowledge through a simple model of fisheries that target a predator (piscivore) and its prey. We solve for the managemen...