AimThe spatial extent (scale) at which landscape attributes are measured has a strong impact on inferred species-landscape relationships. Consequently, researchers commonly measure landscape variables at multiple scales to select one scale (the 'scale of effect') that yields the strongest species-landscape relationship. Scales of effect observed in multiscale studies may not be true scales of effect if scales are arbitrarily selected and/or are too narrow in range. Miscalculation of the scale of effect may explain why the theoretical relationship between scale of effect and species traits, e.g. dispersal distance, is not empirically well supported.Location World-wide.Methods Using data from 583 species in 71 studies we conducted a quantitative review of multiscale studies to evaluate whether research has been conducted at the true scale of effect.Results Multiple lines of evidence indicated that multiscale studies are often conducted at suboptimal scales. We did not find convincing evidence of a relationship between observed scale of effect and any of 29 species traits. Instead, observed scales of effect were strongly positively predicted by the smallest and largest scales evaluated by researchers. Only 29% of studies reported biological reasons for the scales evaluated. Scales tended to be narrow in range (the mean range is 0.9 orders of magnitude) and few (the mean number of scales evaluated is four). Many species (44%) had observed scales of effect equal to the smallest or largest scale evaluated, suggesting a better scale was outside that range. Increasing the range of scales evaluated decreased the proportion of species with scales of effect equal to the smallest or largest scale evaluated. Main conclusionsTo ensure that species-landscape relationships are well estimated, we recommend that the scales at which landscape variables are measured range widely, from the size of a single territory to well above the average dispersal distance.

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Past studies with spatially structured herbivore populations have emphasized the primacy of intrinsic factors (e.g., patch quality), patch geometry (e.g., patch size and isolation), and more recently landscape context (e.g., matrix composition) in affecting local population abundance and dispersal rate. However, few studies have examined the relative importance of each factor, or how they might interact to affect herbivore abundance or dispersal. Here, we performed a factorial field experiment to examine the independent and interactive effects of patch quality (plant biomass, leaf protein, leaf phenolics) and matrix composition [mudflat or non-host grass (Bromus inermis)] on planthopper (Prokelisia crocea) emigration from host-plant patches (prairie cordgrass, Spartina pectinata). In addition, a field survey was conducted to examine the relative importance of patch quality, geography, and matrix composition on planthopper occupancy and density. In the experiment, we found that rates of emigration from low and intermediate quality patches were, on average, 21% percent higher for patches embedded in brome than mudflat. In contrast, the emigration rate was unaffected by matrix composition in nutrient-rich patches. Within matrix types, plant quality had little effect on emigration. In the survey, planthopper density and the patch occupancy rate of planthoppers increased nonadditively with increasing patch size and the percentage of the surrounding matrix composed of mudflat. This study suggests that landscape-level factors, such as the matrix, may be more important than factors intrinsic to the patches.

Conservation organizations must redouble efforts to protect habitat given continuing biodiversity declines. Prioritization of future areas for protection is hampered by disagreements over what the ecological targets of conservation should be. Here we test the claim that such disagreements will become less important as conservation moves away from prioritizing areas for protection based only on ecological considerations and accounts for varying costs of protection using return-on-investment (ROI) methods. We combine a simulation approach with a case study of forests in the eastern United States, paying particular attention to how covariation between ecological benefits and economic costs influences agreement levels. For many conservation goals, agreement over spatial priorities improves with ROI methods. However, we also show that a reliance on ROI-based prioritization can sometimes exacerbate disagreements over priorities. As such, accounting for costs in conservation planning does not enable society to sidestep careful consideration of the ecological goals of conservation.

Spatial optimization approaches that were originally developed to help conservation organizations determine protection decisions over small spatial scales are now used to inform global or continental scale priority setting. However, the different decision contexts involved in large‐scale resource allocation need to be considered. We present a continuous optimization approach in which a decision‐maker allocates funding to regional offices. Local decision‐makers then use these funds to implement habitat protection efforts with varying effectiveness when evaluated in terms of the funder's goals. We illustrate this continuous formulation by examining the relative priority that should be given to different counties in the coterminous United States when acquiring land to establish new protected areas. If weighting all species equally, counties in the southwest United States, where large areas can be bought cheaply, are priorities for protection. If focusing only on species of conservation concern, priorities shift to locations rich in such species, particularly near expanding exurban areas facing high rates of future habitat conversion (e.g., south‐central Texas). Priorities for protection are sensitive to what is assumed about local ecological and decision‐making processes. For example, decision‐makers who doubt the efficacy of local land protection efforts should focus on a few key areas, while optimistic decision‐makers should disperse funding more widely. Efforts to inform large‐scale conservation priorities should reflect better the types of choice that decision‐makers actually face when working over these scales. They also need to report the sensitivity of recommended priorities to what are often unstated assumptions about local processes affecting conservation outcomes.

The ability to disperse among patches is central to population dynamics in fragmented landscapes. Although saproxylic (=dead wood dependent) insects live in extremely fragmented forest ecosystems and comprise a significant proportion of the biodiversity therein, few studies have focused on dispersal of members in this group. We quantified the terrestrial movements of Odontotaenius disjunctus Illiger, a common saproxylic beetle in eastern North American forests. Movement behavior of individual beetles was measured in deciduous forest and two common matrix (=unsuitable) habitats (urban lawn and cattle pasture). Probability of emigrating from a forest fragment was assessed at the high-contrast boundary between forest and pasture. Seasonal, diurnal, and sex-biased patterns of O. disjunctus dispersal were determined from captures at drift fences encircling inhabited logs. Movement was 1.6 and 2.7 times faster and 1.1 and 1.5 times more linear in suitable habitat (forest) than in unsuitable matrix (lawn and pasture, respectively). Net displacement in the forest exceeded predictions of a correlated random walk, but net displacement in matrix habitats was less than expected. When confronted with a high-contrast boundary, O. disjunctus was 14 times more likely to move toward the forest than the pasture. The importance of temperature was indicated by its positive relationship with movement rate and increased diurnal and warm season dispersal activity. Reluctance to cross boundaries into open fields and slow movement within open fields suggest a low likelihood of terrestrial O. disjunctus movement among forest fragments.

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