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Since 2000, collaborative and multidisciplinary field inventories have helped quadruple park coverage in Peru’s richest region., Meeting international commitments to protect 17% of terrestrial ecosystems worldwide will require >3 million square kilometers of new protected areas and strategies to create those areas in a way that respects local communities and land use. In 2000–2016, biological and social scientists worked to increase the protected proportion of Peru’s largest department via 14 interdisciplinary inventories covering >9 million hectares of this megadiverse corner of the Amazon basin. In each landscape, the strategy was the same: convene diverse partners, identify biological and sociocultural assets, document residents’ use of natural resources, and tailor the findings to the needs of decision-makers. Nine of the 14 landscapes have since been protected (5.7 million hectares of new protected areas), contributing to a quadrupling of conservation coverage in Loreto (from 6 to 23%). We outline the methods and enabling conditions most crucial for successfully applying similar campaigns elsewhere on Earth.

Field photographs of plant species are crucial for research and conservation, but the lack of a centralized database makes them difficult to locate. We surveyed 25 online databases of field photographs and found that they harboured only about 53% of the approximately 125,000 vascular plant species of the Americas. These results reflect the urgent need for a centralized database that can both integrate and complete the photographic record of the world’s flora. Field photographs are essential for research and conservation, but are difficult to access since there is no central database or connection between archives. The 25 leading databases hold only 53% of the plant species of the Americas, illustrating the need for increased work on collecting and standardizing this valuable data.

Enhancing the magneto-optical (MO) response of magnetic films and nanostructures is an important issue for a wide variety of applications, including biosensing. Past success via multilayer stacking has been focused primarily on symmetric or periodic geometries. Here, however, the authors find that a quasiperiodic structure exhibits a far larger MO response than a similar periodic structure, over a broad spectral range, even though both samples have otherwise very similar magnetic and optical properties. Model calculations based on local optical properties fail to describe this behavior; more fundamental, nonlocal effects must be the origin of the massively enhanced MO signal.

Invasive plant species can alter belowground microbial communities. Simultaneously, the composition of soil microbial communities and the abundance of key microbes can influence invasive plant success. Such reciprocal effects may cause plant–microbe interactions to change rapidly during the course of biological invasions in ways that either inhibit or promote invasive species growth. Here we use a space-for-time substitution to illustrate how effects of soil microbial communities on the exotic legume Vicia villosa vary across uninvaded sites, recently invaded sites, and sites invaded by V. villosa for over a decade. We find that soil microorganisms from invaded areas increase V. villosa growth compared to sterilized soil or live soils collected from uninvaded sites, likely because mutualistic nitrogen-fixing rhizobia are not abundant in uninvaded areas. Notably, the benefits resulting from inoculation with live soils were higher for soils from recently invaded sites compared to older invasions, potentially indicating that over longer time scales, soil microbial communities change in ways that may reduce the success of exotic species. These findings suggest that short-term changes to soil microbial communities following invasion may facilitate exotic legume growth likely because of increases in the abundance of mutualistic rhizobia, but also indicate that longer term changes to soil microbial communities may reduce the growth benefits belowground microbial communities provide to exotic species. Our results highlight the changing nature of plant–microbe interactions during biological invasions and illustrate how altered biotic interactions could contribute to both the initial success and subsequent naturalization of invasive legume species.

In natural biological communities, species interact with many other species. Multiple species interactions can lead to indirect ecological effects that have important fitness consequences and can cause nonadditive patterns of natural selection. Given that indirect ecological effects are common in nature, nonadditive selection may also be quite common. As a result, quantifying nonadditive selection resulting from indirect ecological effects may be critical for understanding adaptation in natural communities composed of many interacting species. We describe how to quantify the relative strength of nonadditive selection resulting from indirect ecological effects compared to the strength of pairwise selection. We develop a clear method for testing for nonadditive selection caused by indirect ecological effects and consider how it might affect adaptation in multispecies communities. We use two case studies to illustrate how our method can be applied to empirical data sets. Our results suggest that nonadditive selection caused by indirect ecological effects may be common in nature. Our hope is that trait-based approaches, combined with multifactorial experiments, will result in more estimates of nonadditive selection that reveal the relative importance of indirect ecological effects for evolution in a community context.

Both competitors and natural enemies can limit plant population growth. However, demographic comparisons of the effects of these interactions on introduced versus co‐occurring, related native species are uncommon. We asked: (1) does plant competition, insect herbivory, or their combination reduce population growth rate, log λ, of the Eurasian thistle Cirsium vulgare sufficiently to explain its limited invasiveness in western tallgrass prairie; and (2) how do the effects of these interactions compare to those for C. altissimum, its co‐occurring, synchronously‐flowering native congener? We developed integral projection models (IPMs) to estimate log λ for both species, using parameter estimates from field experiments. Our models predicted that the growth potential (growth rate at minimal competition and herbivory) for the introduced thistle (log λ = 3.5 (2.5, 4.6)) was twice as large as for the native thistle (log λ = 1.6 (0.4, 3.1)); however, a high level of competition and ambient insect herbivory together reduced log λ to similar values for both thistle species (C. vulgare: log λ = −1.3 (−2.4, −0.3) vs C. altissimum: log λ = −0.9 (−1.4, −0.3)). This suggests that the introduced thistle was more affected by competition and insect herbivory. For the introduced thistle, neither competition nor insect herbivory alone led to negative log λ. In contrast, for the native thistle, high competition alone also led to negative population growth (log λ = −0.8, percentile limits do not overlap with zero). Ambient herbivory alone prevented the spread for both thistle species (percentile limits include zero). Overall, the results show that interspecific competition followed by ambient levels of insect herbivory strongly constrained log λ for both thistles, limiting C. vulgare invasiveness and C. altissimum abundance. The outcome highlights the importance of synergy between the two biological interactions in limiting plant population growth. Improved understanding of mechanisms limiting log λ for weedy plants enhances our ability to predict when biotic resistance will contribute to invasive plant species management.

The biotic resistance hypothesis is a dominant paradigm for why some introduced species fail to become invasive in novel environments. However, predictions of this hypothesis require further empirical field tests. Here, we focus on evaluating two biotic factors known to severely limit plants, interspecific competition and insect herbivory, as mechanisms of biotic resistance. We experimentally evaluated the independent and combined effects of three levels of competition by tallgrass prairie vegetation and two levels of herbivory by native insects on seedling regeneration, size, and subsequent flowering of the Eurasian Cirsium vulgare, a known invasive species elsewhere, and compared its responses to those of the ecologically similar and co-occurring native congener C. altissimum. Seedling emergence of C. vulgare was greater than that of C. altissimum, and that emergence was reduced by the highest level of interspecific competition. Insect leaf herbivory was also greater on C. vulgare than on C. altissimum at all levels of competition. Herbivory on seedlings dramatically decreased the proportion of C. vulgare producing flower heads at all competition levels, but especially at the high competition level. Competition and herbivory interacted to significantly decrease plant survival and biomass, especially for C. vulgare. Thus, both competition and herbivory limited regeneration of both thistles, but their effects on seedling emergence, survival, size and subsequent reproduction were greater for C. vulgare than for C. altissimum. These results help explain the unexpectedly low abundance recorded for C. vulgare in western tallgrass prairie, and also provide strong support for the biotic resistance hypothesis.

Premise of the Study Biological collections are uniquely poised to inform the stewardship of life on Earth in a time of cataclysmic biodiversity loss. Efforts to fully leverage collections are impeded by a lack of trained taxonomists and a lack of interest and engagement by the public. We provide a model of a crowd-sourced data collection project that produces quality taxonomic data sets and empowers citizen scientists through real contributions to science. Entitled MicroPlants, the project is a collaboration between taxonomists, citizen science experts, and teachers and students from universities and K–12. Methods We developed an online tool that allows citizen scientists to measure photographs of specimens of a hyper-diverse group of liverworts from a biodiversity hotspot. Results Using the MicroPlants online tool, citizen scientists are generating high-quality data, with preliminary analysis indicating non-expert data can be comparable to expert data. Discussion More than 11,000 users from both the website and kiosk versions have contributed to the data set, which is demonstrably aiding taxonomists working toward establishing conservation priorities within this group. MicroPlants provides opportunities for public participation in authentic science research. The project's educational component helps move youth toward engaging in scientific thinking and has been adopted by several universities into curriculum for both biology and non-biology majors.

Both competition and herbivory have been shown to reduce plant survival, growth, and reproduction. Much less is known about whether competition and herbivory interact in determining plant performance, especially for introduced, weedy plant species in the invaded habitat. We simultaneously evaluated both the main and interactive effects of plant neighbors and insect herbivory on rosette growth and seed reproduction in the year of flowering for Cirsium vulgare (bull thistle, spear thistle), an introduced Eurasian species, in tallgrass prairie in 2 years. Effects of insect herbivory were strong and consistent in both years, causing reduced plant growth and seed production, whereas the effects of competition with established vegetation were weak. The amount of herbivore damage inflicted on rosettes did not depend on the presence of neighbor plants. We also found no interaction between competition and herbivory on key parameters of plant growth and fitness. The results of this study contradict the hypothesis that competitive context interacts with insect herbivory in limiting the invasiveness of this introduced thistle. Further, the results provide additional, experimental evidence that high levels of herbivory on established rosettes by native insects exert significant biotic resistance to the invasiveness of C. vulgare in western tallgrass prairie.

Tolerance, or the capacity of a genotype to survive and reproduce following herbivore damage, varies widely across the plant kingdom. One proximate cause of this variation is resource availability, which can influence tolerance through mechanisms such as growth rate and photosynthesis. We examined the effect of high and low soil nutrient levels on the relationship between tolerance and two of its underlying mechanisms, biomass regrowth and photosynthetic upregulation, among genotypes of the Mediterranean annual grass Avena barbata. Although defoliated plants did not reach the same biomass as controls, biomass regrowth was higher at high nutrients. However, increased seed abortion at high nutrients caused tolerance to be the same in both nutrient treatments. Increased seed abortion also uncoupled biomass regrowth from tolerance at high nutrients. We found no evidence for photosynthetic upregulation in defoliated compared to control plants in either nutrient treatment. However, tolerance was positively correlated with predefoliation photosynthetic efficiency at high nutrients. Thus, constitutive photosynthetic efficiency may be a better predictor of tolerance than photosynthetic responses following herbivory in A. barbata. More generally, our results highlight the possibility that the mechanisms of tolerance can differ across resource environments even if tolerance is the same.