As the rate and extent of environmental change increases, traditional perspectives on ecosystem management and restoration are being juxtaposed with approaches that focus on the altered settings now being encountered or anticipated. We suggest that a combination of traditional and emerging frameworks is necessary to achieve the multiple goals of ecosystem management, including biodiversity conservation and provision of other ecosystem services such as food and fiber production, recreation, and spiritual enrichment.An effective approach entails a move away from partitioning the environment into dichotomous categories (eg natural/unnatural, production/conservation, intact/degraded). Instead, landscapes are increasingly characterized by a complex mosaic of ecosystems or "patches" in varying states of modification, each of which delivers various combinations of services and presents assorted management challenges and opportunities. These patches interact and affect broader-scale processes (such as water flows and animal migrations), necessitating the urgent development of a conservation and restoration strategy that recognizes these rapid spatial changes.Here, we focus on an emerging framework that differentiates patches according to the degree of change from a historical state (resulting from altered abiotic factors and biotic compositions), the likely extent to which such changes are reversible, and the effect of altered patches on other patches within the landscape (WebPanel 1). This framework, derived from recent research on novel ecosystems (Hobbs et al. 2009, helps to identify the relative values of ecosystems in different conditions and the management options available in each case. As seen from a landscape perspective, this framework provides a comprehensive approach to decision making and management, including much-needed prioritization of resource allocations.n Managing the whole landscape Recent analyses have highlighted the need for management and restoration efforts to go beyond site-focused interventions and to consider landscape and regional scales (Mentz et al. 2013). Ecosystem managers increas- REVIEWS REVIEWS REVIEWSManaging the whole landscape: historical, hybrid, and novel ecosystems The reality confronting ecosystem managers today is one of heterogeneous, rapidly transforming landscapes, particularly in the areas more affected by urban and agricultural development. A landscape management framework that incorporates all systems, across the spectrum of degrees of alteration, provides a fuller set of options for how and when to intervene, uses limited resources more effectively, and increases the chances of achieving management goals. That many ecosystems have departed so substantially from their historical trajectory that they defy conventional restoration is not in dispute. Acknowledging novel ecosystems need not constitute a threat to existing policy and management approaches. Rather, the development of an integrated approach to management interventions can provide options that are in tune with ...

Weed seed return and seedbank composition, with particular reference to common lambsquarters, were studied in four tillage systems established on a site near Fingal, Ontario. The tillage treatments were moldboard plow, chisel plow, ridge-till, and no-till. The cropping system was a cornsoybean rotation. Tillage effects on weed population composition were assessed after all weed control measures had been implemented. More than 60% of the weed seedbank was concentrated in the upper 5 cm of soil in chisel plow and no-till. The seedbank of the moldboard plow system was more uniformly distributed over depth and larger than the other systems. Common lambsquarters comprised more than 50% of the seedbank in all systems except ridge-till, but only dominated the aboveground weed population in chisel plow. Seedbank populations of common lambsquarters with moldboard plowing were greater than those with ridge-till and no-till, and chisel plow seedbank populations were greater than those in ridge-till. Chisel and moldboard plow systems generally had higher aboveground plant populations of common lambsquarters than the other two systems. Seed production per plant by common lambsquarters was equivalent among the four systems, but estimated seed production per unit area was higher in moldboard plow and chisel plow systems than in the other systems. Populations of common lambsquarters and similar species may produce more seeds and persist in moldboard plow and chisel plow systems; these weeds may produce fewer seeds per unit area and be easier to manage in no-till and ridge-till systems.

Field experiments were conducted from 1995 to 1997 in southern Ontario to determine the influence of tillage and ground cover on the quantity of postdispersal seed predation of common lambsquarters and barnyardgrass. Ground-dwelling invertebrates were the dominant seed predators and were responsible for 80 to 90% of all seeds consumed. Predation was highest in no-till and moldboard-plowed environments (averaging 32% in both) and lowest in chisel-plowed environments (averaging 24%). This indicates that the relationship between the level of disturbance and predation is nonlinear and that other factors, such as the mobility of invertebrates and food availability, may also play important roles in determining the quantity of seed predation. In no-till, the type of crop residue also influenced the quantity of predation, with highest seed predation found in plots with corn residue (averaging 31%) and lowest in those with soybean and wheat residue (24 and 21%, respectively). It is apparent that there is an optimum combination of residue quantity and quality that maximizes the quantity of seed predation. Based on the experimental design used in this study, no feeding preference by seed predators was detected between common lambsquarters and barnyardgrass. Density-dependent feeding, however, was evident for both species. Most biological control efforts have centered around predators with specific feeding habits. We contend that invertebrates with opportunistic feeding strategies that feed on weed seeds may be the most significant broad spectrum and natural form of biological weed control affecting weed population dynamics. Populations of beneficial arthropods should be conserved, and management strategies that augment the size of their natural populations should be encouraged.

In a 6-yr study on four farms (36 fields) in Ontario, Canada, we tested the effects of tillage (moldboard, chisel plow, no tillage) and crop rotations (continuous corn, corn-soybean, corn-soybean-winter wheat) on emerged and seedbank weed species diversity and density. Aside from the imposed experimental treatments, all other management was generally consistent among farms. Tillage had the largest effect on weed diversity and density. No tillage promoted the highest weed species diversity, chisel plow was intermediate, and moldboard plow resulted in the lowest species diversity. These results are consistent with ecological succession theory. The increase in weed species diversity resulted from 20 species being associated with no tillage systems, 15 of which were winter annuals, biennials, or perennials. Emerged weed density was affected only by tillage. Over 6 yr, seedbank declined in no-tillage systems from 41,000 to 8,000 seeds m Ϫ3 . Crop yields were not affected by tillage or crop rotation. In practical terms, reduced tillage in combination with a good crop rotation may reduce weed density and expenditures on weed management.Nomenclature: Glyphosate; corn, Zea mays L. 'Pioneer 3902'; soybean, Glycine max (L.) Merr. 'KG 40'; winter wheat Triticum aestivum L.

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