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Ecologists have explored community assembly through the framework of ecological filters, which predicts that species must overcome a series of challenges (i.e. pass through "filters") to successfully establish in a given community. In the context of restoration, these filters (dispersal, abiotic, and biotic) can be manipulated to alter the resulting plant community by favoring native species or disadvantaging non‐native invasive species. We conducted two studies manipulating assembly filters at two California grassland sites previously dominated by non‐native species. At Site 1, we explored how variations in sequential seeding of native grasses and forbs (to overcome dispersal and biotic filters caused by priority effects) influenced the resulting community. At Site 2, we explored how thatch removal (to overcome the abiotic filter of light limitation) and herbicide‐based weed control (to overcome the biotic filter of competition from non‐native species) influenced the addition of native forbs into a partially restored grassland. Native forbs at Site 1 did not suffer from arriving after grasses, but native grasses benefited when given 1 year priority over forbs. At Site 2, dethatching increased native forb cover in a high rainfall year. Herbicide application reduced non‐native grass cover in dethatched plots without negatively affecting native cover. Native forb and grass cover were significant predictors of non‐native grass cover. However, they accounted for only 29% of the variation observed, suggesting there are other influential factors not considered in this study. Our results suggest that forbs can be incorporated into established native grasslands more successfully after dethatching. [ABSTRACT FROM AUTHOR]

Feral rye is an invasive North American weed that evolved from domesticated rye in the last century. In order to determine how this weed diverged from its cultivated ancestor and whether it has evolved regional differences across its new range in the western United States, we planted both feral rye from different regions and its progenitor in three common garden sites spanning the North-South axis of that range (eastern Washington, northern California, and southern California, respectively). We measured seedling emergence, survival, vegetative growth, flowering phenology, and reproductive output concurrently across sites over a single growing season. All traits were found to be genetically based. All feral populations were typically shattering contrasting with domesticated rye's typically non-shattering seed head. They also flowered later, tillered more, grew shorter, and produced smaller seeds in at least one population. Near the center and proposed origin of its introduced range, all feral rye populations produced significantly more seed than cultivars. Northern feral populations flowered later than southern populations and cultivars. Shifts were not symmetrical: southern populations performed well at all sites. But northern populations showed more evidence of local adaptation, faring poorly in southern California. Clearly, feral rye has evolved from its cultivated progenitor by more than just acquiring shattering. Furthermore, it has diverged regionally, although not all populations are fully locally adapted. Notably, feral rye populations exhibited a greater range of phenotypes than rye cultivars, suggesting that its evolution is not simply due to selection acting on existing variation within individual cultivars. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. 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$13·7 million - almost the entire budget of $14 million. 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. [ABSTRACT FROM AUTHOR]

The evolution of problematic plants, both weeds and invasives, is a topic of increasing interest. Plants that have evolved from domesticated ancestors have certain advantages for study. Because of their economic importance, domesticated plants are generally well-characterized and readily available for ecogenetic comparison with their wild descendants. Thus, the evolutionary history of crop descendants has the potential to be reconstructed in some detail. Furthermore, growing crop progenitors with their problematic descendants in a common environment allows for the identification of significant evolutionary differences that correlate with weediness or invasiveness. We sought well-established examples of invasives and weeds for which genetic and/or ethnobotanical evidence has confirmed their evolution from domesticates. We found surprisingly few cases, only 13. We examine our list for generalizations and then some selected cases to reveal how plant pests have evolved from domesticates. Despite their potential utility, crop descendants remain underexploited for evolutionary study. Promising evolutionary research opportunities for these systems are abundant and worthy of pursuit. [ABSTRACT FROM AUTHOR]

Crop-wild hybridization has been documented in many cultivated species, but the ecological and genetic factors that influence the likelihood or rate that cultivar alleles will introgress into wild populations are poorly understood. Seed predation is one factor that could mitigate the spread of otherwise advantageous cultivar alleles into the wild by reducing seedling recruitment of crop-like individuals in hybrid populations. Seed predation has previously been linked to several seed characters that differ between cultivated and wild sunflower, such as seed size and oil content. In this study, seed morphological and nutritional characters were measured in a segregating population of sunflower crop-wild hybrids and wild and cultivated lines. Seed predation rates among lines were then assessed in the field. The relationship between seed predation and seed characters was investigated and quantitative trait loci (QTL) were mapped for all traits. There was no effect of seed type (hybrid vs. parents) on seed predation, although a trend toward more early predation of wild seeds was observed. Within the hybrids, seed predators preferred seeds that contained more oil and energy but were lower in fibre. The relationship between seed predation and oil content was supported by co-localized QTL for these traits on one linkage group. These results suggest that oil content may be a more important determinant of seed predation than seed size and provide molecular genetic evidence for this relationship. The cultivar allele was also found to increase predation at all QTL, indicating that post-dispersal seed predation may mitigate the spread of cultivar alleles into wild populations. [ABSTRACT FROM AUTHOR]

• Introgression of cultivar alleles into wild plant populations via crop–wild hybridization is primarily governed by their fitness effects as well as those of linked loci. The fitness of crop–wild hybrids is often dependent on environmental factors, but less is understood about how aspects of the environment affect individual cultivar alleles. • This study investigated the effects of naturally occurring herbivory on patterns of phenotypic selection and the genetic architecture of plant–herbivore interactions in an experimental sunflower crop–wild hybrid population in two locales. • Phenotypic selection analyses suggested that cultivar alleles conferring increased size were generally favored, but at one site cultivar-like flowering time was favored only if three types of herbivory were included in the selection model. Quantitative trait locus (QTL) mapping identified three regions in which the cultivar allele conferred a selective advantage for a number of co-localized traits. Quantitative trait loci for several measures of insect herbivory were detected and, although the cultivar allele increased herbivory damage at the majority of these QTLs, they rarely colocalized with advantageous cultivar alleles for morphological traits. • These results suggest that a subset of cultivar traits/alleles are advantageous in natural environments but that herbivory may mitigate the selective advantage of some cultivar alleles. [ABSTRACT FROM AUTHOR]

The domestication and improvement of crop plants have long fascinated evolutionary biologists, geneticists, and anthropologists. In recent years, the development of increasingly powerful molecular and statistical tools has reinvigorated this now fast-paced field of research. In this paper, we provide an overview of how such tools have been applied to the study of crop evolution. We also highlight lessons that have been learned in light of a few long-standing and interrelated hypotheses concerning the origins of crop plants and the nature of the genetic changes underlying their evolution. We conclude by discussing compelling evolutionary genomic approaches that make possible the efficient and unbiased identification of genes controlling crop-related traits and provide further insight into the actual timing of selection on particular genomic regions. [ABSTRACT FROM AUTHOR]

Feral rye ( Secale cereale) is a serious, introduced weed of dry land agricultural regions of the western United States. It closely resembles cultivated cereal rye ( Secale cereale cereale L.) with the exception of having a shattering seed head. Feral rye may have originated from hybridization of cultivated rye with mountain rye, Secale strictum, as past studies of northern Californian populations suggest, or directly from volunteer cultivated rye. We characterized the genetic structure of feral rye populations across a broad geographical range and reexamined evidence for hybrid origin versus direct evolution from domesticated cultivars. Eighteen feral populations were examined from three climatically distinct regions in the western United States. Seven cultivars, four mountain rye accessions, and one wild annual relative ( Secale cereale ancestrale) were included in our analysis as possible progenitors of feral rye. Individual plants were scored for 14 allozyme and three microsatellite loci. Estimates of genetic diversity in feral populations were relatively high compared to those of the possible progenitors, suggesting that the weed had not undergone a genetic bottleneck. Weed populations had no geographical structure at either a broad or a local scale, suggesting idiosyncratic colonization and gene-flow histories at each site. Feral rye populations were no more closely related to mountain rye than cultivars were. They were, however, weakly clustered as a distinct lineage relative to cultivars. Our results do not support an interspecific hybrid origin for feral rye, but do suggest that the sampled populations of feral rye share a common ancestry that may explain its weedy nature. [ABSTRACT FROM AUTHOR]

Tests the effects of above- and below ground competition and evaluates insect herbivory on the growth of a common cactus, Opuntia fragilis. Manipulation of prairie vegetation and surface water availability; Effect of water supplementation on cactus growth or on insect herbivory; Indirect effect of habitat-mediated variation in feeding by insects.