Ecological restoration is a multibillion dollar industry critical for improving degraded habitat. However, most restoration is conducted without clearly defined success measures or analysis of costs. Outcomes are influenced by environmental conditions that vary across space and time, yet such variation is rarely considered in restoration planning. Here, we present a cost-effectiveness analysis of terrestrial restoration methods to determine how practitioners may restore the highest native plant cover per dollar spent. We recorded costs of 120 distinct methods and described success in terms of native versus non-native plant germination, growth, cover, and density. We assessed effectiveness using a basic, commonly used metric (% native plant cover) and developed an index of cost-effectiveness (% native cover per dollar spent on restoration). We then evaluated success of multiple methods, given environmental variation across topography and multiple years, and found that the most successful method for restoring high native plant cover is often different from the method that results in the largest area restored per dollar expended, given fixed mitigation budgets. Based on our results, we developed decision-making trees to guide practitioners through established phases of restoration-site preparation, seeding and planting, and maintenance. We also highlight where additional research could inform restoration practice, such as improved seasonal weather forecasts optimizing allocation of funds in time or valuation practices that include costs of specific outcomes in the collection of in lieu fees.

We examined the effects of species, habitat type (open pasture, forest, and beneath isolated pasture trees), and distance from the forest/pasture edge (25 m and 250 m) on post‐dispersal seed predation of ten animal‐dispersed species near the Las Alturas Biological Station in southern Costa Rica. We also compared the amount of seed predation due to vertebrate and insect predators. Levels of seed predation were extremely species‐specific, ranging from 20–100 percent of seeds consumed during the 30 day study period. However, the proportion of seeds remaining was not correlated with seed size. Overall, seed mortality did not differ between the forest and open pasture habitats, but was significantly lower under isolated pasture trees. Individual species differed in which habitat they suffered the highest levels of predation. For eight of ten species studied, levels of seed predation did not vary significantly with distance from the foredpasture edge in any habitat. The majority of the post‐dispersal seed predation was due to mammalian predators. The results of this and other studies suggest that post‐dispersal seed predation may influence patterns of forest regeneration in disturbed areas. RESUMEN Investigamos el efecto de la especie, el tipo de hábitat (pastizal abierto, bosque, y debajo de árboles aislados en el pastizal), y la distancia a la orilla del bosque, sobre la depredación de semillas de diez especies dispersadas por animales cerca de la Estación Biológica Las Alturas en el sur de Costa Rica. Además comparamos la depredación causada por vertebrados e insectos. Los niveles de depredación fueron muy variables entre especies, entre el 20 y 100 por ciento fué depredado durance los 30 dias del estudio. No hubo correlación entre la proporción de semillas no depredadas y su tamaño. No existió una diferencia entre el bosque y el pastizal en la mortalidad total de las semillas, pero la mortalidad fue menor debajo de 10s árboles aislados. La depredación de semillas de diferentes especies varió en relación al hábitat. Para ocho de las diez especies los niveles de depredación no variaron en relación con la distancia a la orilla del bosque en ninguno de 10s hábitats. La mayoría de la depredación fué ocasionada por mamíferos. Los resultados de éste y otros estudios sugieren que la depredación de semillas influye en la regeneración del bosque en tierras degradadas.

Summary1. In general, conservation seeks to prevent further habitat loss but in many cases there is a need to reverse habitat degradation. Restoration of habitat is necessary to achieve biodiversity conservation goals but often it is a costly and time-intensive process. Prioritization of where and when habitat is restored can help to ensure the cost-effective delivery of desired outcomes. 2. We develop a restoration prioritization decision support tool to identify the combination of restoration sites and the schedule for their implementation most likely to deliver the greatest utility for a fixed budget and operational constraints. We use a case study to apply our prioritization approach in order to illustrate the data that can be employed to parameterise the analysis and the outputs that are able to inform restoration planning. We compare restoration schedules under alternative utility functions to demonstrate trade-offs associated with different objectives, assumptions and preferences for particular outcomes. 3. Our prioritization approach is spatially and temporally explicit and accounts for the costs and benefits of restoration, the likelihood of restoration success, the probability of stochastic events, feedbacks, time lags and spatial connectivity. 4. Through collaboration with restoration practitioners we derive quantitative and spatially explicit data on each site requiring restoration. We determine the relative priority for restoring each site and develop a restoration schedule over 20 years. 5. Our results showed that after 20 years a little over a half of the sites requiring restoration are likely be successfully restored, while the total expenditure at our site will be c. US$13AE7 millionalmost the entire budget of $14 million. 6. Synthesis and applications. Our restoration prioritization approach provides a schedule for where and when restoration should occur, and also provides operational guidance and support for cost-effective restoration planning such as informing the likely total cost of restoration.

The Central Valley of California is noted for its dearth of remnant native grass populations and for low native grass seedling establishment within grasslands now dominated by non-native annual species. In contrast, remnant populations are common along the coast, and studies have shown an ability for seedlings and adults to compete with nonnative annual grasses. The invasibility of well-established populations of native grasses in the Central Valley remains unclear. The objectives of this study were to compare the invasibility of native grasses differing in density and species composition and, given the species in this study, to assess the ability of mixes with greater species richness to resist invasion relative to their abilities in monoculture. In the Sacramento Valley of California, six species of native grasses were planted at three densities in monospecific and mixed-species plots. Percent cover of native perennial and non-native annual grasses was measured in years 2 and 3, and biomass was sampled in year 5. Native grass biomass and, to a lesser extent, species composition were important in explaining variation in non-native grass invasibility in the fifth year. Species-rich treatments did not experience less invasion than would be expected by the proportional invasibility of each species in monoculture. However, invasibility of plots consisting of slower growing, shorter statured species decreased over time, suggesting a successional benefit to diverse communities. This study demonstrates that established stands of native grasses in the Sacramento Valley can resist invasion by non-native annual grasses and that stand biomass is a particularly important factor in determining invasibility.

No abstract