Establishment Of Native Species Research Articles

Testing prescribed burning to shift an agronomic grass community to a diverse native plant community

Prescribed burning can be an effective land management tool. Here, we study changes in plant diversity and composition following experimental fire disturbance in microcosm units extracted from a twenty-five-year-old historically reclaimed grassland located at Highland Valley Copper mine in British Columbia (B.C.), Canada. Experimental microcosm units were dominated by agronomic grass species Elymus lanceolatus, Thinopyrum intermedium and Bromus inermis. The disturbance treatment was fire intensity, represented by three levels (light, moderate, and heavy), replicated six times per treatment. Fire intensity was controlled by modifying the weight of dried litter applied to each microcosm unit (50 g,150 g, 200g), along with the time each grass turf was burned (10 s, 15 s, 20 s). One day after the fire treatment was applied, microcosm units were seeded with a native species mix consisting of six grassland species common to southern B.C. to examine effectiveness of plant establishment postburn. Disturbance treatments resulted in higher overall alpha diversity, richness, evenness, and beta diversity. Plant community changes included colonization of seeded native forbs, grasses, and legumes in response to disturbance. Aboveground net primary productivity (ANPP) was net neutral within the light and moderate burning disturbance treatments but resulted in increased ANPP with heavy disturbance. Litter mass reduced plant diversity and ANPP, indicating that litter was a major factor in plant community dynamics. These results suggest disturbance by burning leads to short term positive plant community response towards increasing diversity of semi-arid grasslands, and aids in shifting plant communities to higher diversity composed of an increase in native plant species. Our results also suggest that without active management the gains observed in native species establishment might quickly be out shadowed and restricted by the previously dominant agronomic plant community.

A review of natural and managed revegetation responses in two de-watered reservoirs after large dam removals on the Elwha River, Washington, USA

Large dam removals are increasing in frequency and the response of natural and managed revegetation is a critical consideration for managed restoration of dewatered reservoir landscapes post dam removal. The removal of two large dams on the Elwha River in 2011-2014 provides insight into reservoir revegetation. We review literature and datasets from 2012 through 2018, 1-6 years since reservoir dewatering, to compare pre-dam removal predictions on the Elwha to post-dam removal of natural revegetation, managed revegetation effects and invasive non-native vegetation response. Pre-dam removal hypotheses about natural revegetation did not predict species performance on reservoir sediments, seed rain patterns, or seed bank response. Sediment texture and landform affected multiple aspects of revegetation, including vegetation cover, species richness, woody stem densities and species composition. Reservoir drawdown timing influenced species composition and seedling densities. Predictions about managed revegetation effects were mixed. Planting trees and shrubs did not accelerate woody cover but did increase species richness. Seeding reduced non-native vegetation frequency and species richness, had no effect on vegetation cover on fine sediments, but increased vegetation cover on coarse sediments. Planting trees and shrubs during drawdown appeared to result in higher survival rates compared to plantings installed 1+ years post drawdown. Seeding Lupinus rivularis (riverbank lupine) on coarse sediments was successful and increased foliar nitrogen in planted conifers. Invasive non-native vegetation was correctly predicted to be more abundant in the Aldwell reservoir but did not preclude native species establishment in either reservoir, likely due to rapid establishment of native species and robust management that occurred before, during and after dam removal.

Dominant species establishment may influence invasion resistance more than phylogenetic or functional diversity

Abstract Phylogenetic and functional diversity are theorised to increase invasion resistance. Experimentally testing whether plant communities higher in these components of diversity are less invasible is an important step for guiding restoration designs. To investigate how phylogenetic and functional diversity of vegetation affect invasion resistance in a restoration setting, we used experimental prairie restoration plots. The experiment crossed three levels of phylogenetic diversity with two levels of functional diversity while species richness was held constant. We allowed invaders to colonise plots; these included native species from neighbouring plots and non‐native invasive species from a surrounding old field. We tested if invader biomass was influenced by phylogenetic and functional diversity, and phylogenetic and hierarchical trait distances between invaders and planted species. We binned each invader into three categories: native species from neighbouring experimental plots (site‐specific invaders), native species not part of the experimental species pool (native invaders) or non‐native species (non‐native invaders). Counter to expectation, both non‐native and native invaders became more abundant in more phylogenetically diverse plots. However, plots with higher abundance of planted Asteraceae, a dominant family of the tallgrass prairie, had lower invader biomass for both native and non‐native invaders. We also found that hierarchical trait differences shaped invasion. The species that became most abundant were non‐native invaders that were taller, and native invaders with low specific leaf area relative to planted species. Site‐specific invaders were not influenced by any plot‐level diversity metrics tested. Synthesis and application: Our results suggest that greater phylogenetic diversity may lower resistance to invasion. This effect may be due to more even but sparser niche packing in high‐diversity plots, associated with greater availability of unsaturated niche space for colonisation. However, trait composition fostered invasion resistance in two ways in our study. First, establishment of native species with strongly dominant traits may confer invasion resistance. Second, species mixes that optimise trait differences between planted vegetation and likely invaders may enhance invasion‐resistance.

Road Impact on Plant Colonization in the Arid Timanfaya National Park.

Roads have the potential to alter local environmental conditions, such as the availability of water and nutrients, and rapidly create suitable habitats for the establishment of both native and non-native plant species, transforming the ecosystems. This is a challenge in Timanfaya National Park and Los Volcanes Natural Park on Lanzarote Island, protected areas that have experienced primary succession after recent volcanic eruptions. In arid ecosystems, changes in abiotic conditions along roadsides might facilitate colonization and plant growth. We analyzed the effect of roads and road type on plant species composition and richness at a spatiotemporal scale. Vascular plant species were systematically recorded at three distances from the road edge on both sides, across fourteen zones in the wet and dry seasons, for three years. Results showed that there were slight differences on species composition depending on the distance to the road edge, as well as on the zones. Species richness was also determined by the interaction of the position, zones, and season, being higher at the road edge. Furthermore, zones with higher traffic intensity showed a higher presence of both native and non-native species. This study highlights the importance of the awareness about the road impacts on species composition by enhancing the colonization capacity of species while facilitating the entry of invasive ones. Good management practices regarding infrastructures in natural protected areas are crucial for the conservation of their unique flora, landscapes, and natural succession processes.

Wood density and leaf traits independently relate to growth rate of naturally regenerated tree species in Araucaria angustifolia plantations in the Atlantic Forest, Argentina

Tree plantations can facilitate the establishment of native trees, thus providing opportunities for the ecological restoration or rehabilitation of degraded forest lands. Stand variables can influence the establishment of native tree species, but few studies have been carried out to determine how sapling growth response to stand variables varies among functionally different species. We evaluated the effect of stand age, stand basal area, tree density, and time since last logging on stem diameter growth rates, as well as the dependence of such effect on whole plant, stem, and leaf functional traits. We measured the stem diameter increment on 280 individuals of 22 species in permanent plots for a period of 2 years in araucaria ( Araucaria angustifolia (Bertol.) Kuntze) plantations in the Atlantic Forest, NE Argentina. Increasing all-species basal area and plantation age negatively affected the growth rates, and such effect tended to be higher in species with low wood density. Two functional axes independently explained growth rate differences between species in growth rate. Growth rates increase with decreasing wood density, increasing leaf phosphorus and potassium content, and decreasing specific leaf area. Among species that are similar in the traits associated with the first functional axis, plant growth increases with increasing leaf nitrogen content.

Can legume seeds establish after land degradation by buffelgrass? Evidence to initiate restoration in Central Sonora, Mexico

AbstractBuffelgrass (Pennisetum ciliare) has been introduced in many localities of northwestern Mexico for cattle grazing. Recent studies have documented how the conversion of natural vegetation to buffelgrass pastures affects several ecological processes that result in high levels of desertification and the subsequent abandonment of lands. However, no previous study has documented successful restoration in these habitats. In this paper we report the results of several experiments focused on the restoration of these areas using native legume species of the region. We selected a degraded buffelgrass pasture considered unproductive by local ranchers in central Sonora. We carried out experiments to evaluate seed removal, seedling emergence, and seedling establishment of native legumes species (Prosopis glandulosa, Parkinsonia microphylla and P. praecox). Our results showed that P. microphylla had greater emergence (10%) than the other two species despite the high seed removal recorded. In addition, P. microphylla was the species with the highest survival (1.4%). Thus, our results show that ecological recovery using native species is possible in desertified buffelgrass pastures. Considering the ecological benefits of P. microphylla in the Sonoran Desert (i.e., nurse plant, positive associations, plant‐growth promoting), this species could be considered highly valuable in restoration procedures.

Establishment of native seedlings species as an indicator of ecological restoration of riparian forest, Cerrado, DF, Brazil

This study evaluated the survival of seedlings of native species of Cerrado - Brazil and its potential as an indicator of ecological restoration of riparian forests. The factors affecting survival were also analyzed. The experiment consisted of three planting models with three replications (T1 = nucleation: Anderson model; T2 = nucleation: Anderson model + artificial perches; T3 = filling line and diversity line). The influence of factors such as leaf herbivory, stem herbivory, absence of leaves (predation, dehydration or malnutrition) and sprouting/regrowth survival were assessed by cluster analysis. The survival rates ranged from 58.6 to 100% (average 73.6%). Out of eighteen species, fifteen showed survival rate above 60%, and could be potentially used in the restoration of degraded areas. The hierarchical clustering using survival efficiency and biotic factors resulted in the distinction of two groups of species with high frequency of leaves and stem herbivory, differing statistically (test “t”, p < 0.05) in the sprouting and regrowth. The survival efficiency shows potential of being used as a restoration indicator.

Tree diversity in riparian forests immersed in a pasture with Urochloa decumbens (Stapf) R.D. Webster (Poaceae) grass under domain of the Atlantic Forest, Brazil

The riparian vegetation along water courses and the health of the river’s basin, regarding the aquatic and terrestrial ecosystems associated with them, are widely discussed in literature. However, the maintenance of the services and the conservation role that riparian forests provide to flora and fauna may be affected by the regional matrix that surrounds the water course and by the length and composition of the riparian vegetation associated with them. This study aimed to evaluate the relationships among the grass cover and arboreal species diversity in three watercourses surrounded by a pasture dominated with the alien grass Uroclhoa decumbens (Stapf) R.D. Webster (former Brachiaria decumbens). Two hypotheses were tested: (i) watercourses with larger riparian forest width present higher richness and abundance of native and zoochoric tree species and those associated to late succession stages, and (ii) watercourses with larger riparian forest width present a lower grass cover on their interior. The study was conducted under domain of Semideciduous Seasonal Forest, belonging to the Atlantic Forest biome, municipality of Londrina, Paraná State, south Brazil. The regional climate is Köppen’s Cfa humid subtropical. The soil is classified as a mosaic of eutroferric red nitosols and lithosols. The studied sites mostly comprise pasture with U. decumbens alien grass and small patches of woody vegetation amidst an open pasture dominated by species attributed to the first’s stages of secondary succession. The studied site is immersed in Cambé’s River watershed and contain three watercourses, Cristal River, tributary to São Lourenço River, that, in turn, is tributary to Cambé River. All watercourses are classified as small rivers (Brazilian Forestry Code, federal law: n. 12.651/2012), with length inferior to 10 m between both riversides. The riparian vegetation shares similar characteristics and structure, encompassing woody vegetation with pioneer trees species and high canopy openness. All riparian forests are immersed in pastures with U. decumbens grass. Transects of 200 meters long, measuring one meter wide from the line on both sides of the transect, and one square plot (25 m2) were allocated on the interior of each riparian forest. Transects were evaluated as arboreal species richness and the length of the riparian forest strip. In each plot, the arboreal vegetation was inventoried as species richness, abundance and density, and the U. decumbens cover was measured. The riparian forest width was arranged in two classes, forests with width ≤ 5 m or ≥ 10 m. The studied forests were compared as richness, abundance, density, and grass cover. The correlations among the riparian vegetation with the forest width and grass coverage (%) were evaluated. Species richness, abundance and density did not differ among the watercourses. However, species abundance and density presented positive correlations with the riparian forest width, indicating that the larger is the riparian vegetation, the higher is the species density. Grass cover presents a strong negative correlation with the riparian forest width, indicating that narrow strips of woody vegetation present higher grass cover. A high positive correlation was observed with riparian strip width and native trees, suggesting that native woody species establishment is limited by the riparian strip width and that those rustic trees species are more capable to colonize these environments. Also, the correlation found with species that present abiotic syndromes and pioneer species indicates that trees that can colonize open areas are more suitable to establish on narrow strips of vegetation amidst a pasture. The relationships observed with zoochoric trees suggests that the fauna that visits these forests are tolerant to open areas and visit these areas independently of their vegetation width. The larger riparian forests present lower grass cover and these can be related to shadow micro-sites that reduce the luminosity which can affect the permanence potential of the dominance of U. decumbens. In this way, the data suggests that few plants can establish in these pasture landscape, and those more rustic trees which are able to establish under open areas, high grass cover and canopy openness, and that re-sprout after a fire, became more dominant. For these watercourses, with narrow riparian vegetation strips surrounded by an U. decumbens pasture, the high grass cover can restrict and plant diversity, acting on the course and velocity of secondary succession in these areas.

Multi-Seed Zea Pellets (MSZP) for increasing agroecosystem biodiversity

AbstractIntensive agricultural crop production is typically associated with low biodiversity. Low biodiversity is associated with a deficit of ecosystem services, which may limit crop yield (e.g., low pollination of insect-pollinated crops) at the individual field level or exacerbate the landscape-level impacts of intensive agriculture. To increase biodiversity and enhance ecosystem services with minimal loss of crop production area, farmers can plant desirable non-crop species near crop fields. Adoption of this practice is limited by inefficiencies in existing establishment methods. We have developed a novel seed-molding method allowing non-crop species to be planted with a conventional corn (Zea mays L.) planter, reducing labor and capital costs associated with native species establishment. Common milkweed (Asclepias syriaca L.) was selected as a model native species, because Asclepias plants are the sole food source for monarch butterfly (Danaus plexippus L.) larvae. Stratified A. syriaca seeds were added to a mixture of binder (maltodextrin) and filler (diatomaceous earth and wood flour) materials in a 3D-printed mold with the dimensions of a corn seed. The resulting Multi-Seed Zea Pellets (MSZP), shaped like corn seeds, were tested against non-pelleted A. syriaca seeds in several indoor and outdoor pot experiments. Molding into MSZP did not affect percent emergence or time to emergence from a 2-cm planting depth. Intraspecific competition among seedlings that emerged from an MSZP did not differ from competition among seedlings that emerged from a cluster of non-pelleted seeds. These findings demonstrate the potential of MSZP technology as a precise and efficient method for increasing agroecosystem biodiversity.

LARGER SEED MASS PREDICTS HIGHER GERMINATION AND EMERGENCE RATES IN SANDY GRASSLAND SPECIES WITH NON-DORMANT SEEDS

The lack of knowledge on the traits related to the germination and establishment of native plant species represents obstacles to restoration. Seed mass, germination and emergence variability from two characteristic grasses (Festuca vaginata and Stipa borysthenica), and two dicots (Centaurea arenaria and Dianthus serotinus) of Hungarian sandy grasslands from altogether 34 localities were tested. Our results showed that seed mass had a significant positive effect on germinability of the dicots and on seedling emergence of all species. The laboratory germination capacity of S. borysthenica was low due to dormancy. We found a significant variability among seed traits and emergence between localities in all the species except for the germination of S. borysthenica. This significant variation among populations might be explained by local adaptation or maternal effects. We conclude that germination under laboratory-regulated conditions is a good predictor of seedling emergence for restoration projects, but limited to species with non-dormant seeds.

Increased diversity of the species pool via seeding augments establishment of native species in experimental vacant‐lot restorations

AbstractQuestionThe harsh geophysical template characterized by the urban environment combined with people's choices has led ecologists to invoke environmental filtering as the main ecological phenomenon explaining urban biodiversity patterns. Yet, dispersal is often overlooked as a driving factor, especially on expanding vacant land. Does overcoming dispersal limitation by seeding native species in urban environments and increasing the functional or phylogenetic diversity of the seeding pool increase native plant species diversity and abundance in urban vacant land?LocationBaltimore, Maryland, USA.MethodsWe took an experimental approach to learn how different dimensions of plant biodiversity within a regional species pool augmented via seed additions, can explain variation in community structure over a three‐year period. Vacant lots were cleared and manipulated with seeding treatments of high or low phylogenetic and functional diversities from a pool of 28 native species. Establishment success, total native cover and native‐species richness were followed and compared to cleared, unseeded control lots as well as unmanipulated lots.ResultsSeeding increased native plant abundance and richness over uncleared plots, as well as cleared and unseeded control plots. Phylogenetically diverse seed mixtures had greater establishment success than mixtures composed of closely related species. Diversifying seed mixtures increased the likelihood of including species that are better able to establish on vacant land. However, there were no differences in varying levels of either functional or phylogenetic diversity.ConclusionsAugmenting the regional species pool via diverse seed mixtures can enhance native plant cover and richness under the harsh environmental conditions conferred by land abandonment.

Assessing Arthropod Communities during Bermudagrass Pasture Conversion to Diverse Native Grassland on the Southern Great Plains of North America

Plant communities change during the process of converting bermudagrass (Cynodon dactylon [L.] Pers.) pasture monocultures to diverse native grasslands. Our hypothesis was that suppression of bermudagrass and grazing of seeded post-native grassland affected composition of arthropod communities in small plots. Our objectives were to use sweep nets and pitfall traps to collect insects and study their diversity and abundance as affected by four bermudagrass suppression methods and two post-management grazing regimes during 2 years following treatment applications at a Cross Timbers Ecoregion site in northcentral Texas. The first year after suppression of bermudagrass, plant diversity was greatest in plots treated with glyphosate, effectively removing exotic grass and allowing establishment of diverse native vegetation. This resulted in greater insect diversity but less abundance compared to treatments in which bermudagrass was not effectively removed. In plots where residual imazapyr prevented establishment of native seedlings, insect diversity and abundance were less. Short-duration, intensive grazing by cattle increased insect diversity 18% the first year. The second year after suppression of bermudagrass, treatments affected insect abundance only when grazing had not occurred. As in the first year, insects were more abundant in check plots dominated by bermudagrass; however, abundance in imazapyr-treated plots was comparable to glyphosate-treated plots because the residual effects of imazapyr were less after 20 months and weeds volunteered in those plots and attracted canopy-dwelling insects. Results support the use of glyphosate to remove bermudagrass if greater arthropod diversity is desired. Results also indicated that short-term grazing post-seeding promoted greater plant and subsequent insect diversity, but only during establishment of native grassland species.

Species provenance and traits mediate establishment and performance in an invaded grassland

Abstract In many invaded grasslands, dominant exotic species can produce large amounts of litter that modify local abiotic conditions and species' interactions. These novel conditions can reduce native species abundance and promote the persistence of exotic species, yet the strength of this disparity may be influenced by how consumer pressure interacts with litter accumulation. Consumers may exacerbate this disparity by preferentially targeting native species or by promoting heterogeneity in microhabitats due to their movement and small‐scale ground disturbances that favours fast growing exotic species. How species respond to litter accumulation and consumer pressure may depend on either evolutionary differences, whereby exotics species may benefit from a lack natural predators, or by functional differences, in which species' physiological traits may confer fitness advantages to low‐light conditions or herbivory or granivory pressure. We examined the impact of litter presence and small mammal herbivory on the establishment and reproduction of functionally diverse exotic versus native species seeded across sites that naturally vary in resource availability in an annual invaded California grassland. We assessed whether seed mass and leaf nitrogen content (LNC) were predictive of successful establishment and reproduction. Litter accumulation affected exotic and native species differently, with litter significantly decreasing native recruitment and reproduction, while exotics were largely unaffected. Small mammals had a slight positive effect on the establishment of native species when litter was present but did not influence exotic species. Regardless of species provenance, larger seeded species established at a higher density while species with lower leaf nitrogen content had a higher density of reproductive individuals. Native species that successfully established and reproduced were functionally different in LNC than the resident community, while successful exotic species were functionally more similar to the resident community in LNC. Our study demonstrates that exotic species outperformed native species regardless of the presence of litter or herbivory pressure. Without the removal or thinning of litter, it is likely that exotic species will continue to dominate, resulting in positive feedback that further favours the persistence of exotic species within this invaded grassland system. Read the free Plain Language Summary for this article on the Journal blog.

Inoculation with native soil improves seedling survival and reduces non‐native reinvasion in a grassland restoration

Losses of grasslands have been largely attributed to widespread land‐use changes, such as conversion to row‐crop agriculture. The remaining tallgrass prairie faces further losses due to biological invasions by non‐native plant species, often with resultant ecosystem degradation. Of critical concern for conservation, restoration of native grasslands has been met with little success following eradication of non‐native plants. In addition to the direct and indirect effects of non‐native invasive plants on beneficial soil microbes, management practices targeting invasive species may also negatively affect subsequent restoration efforts. To assess mechanisms limiting germination and survival of native species and to improve native species establishment, we established six replicate plots of each of the following four treatments: (1) inoculated with freshly collected prairie soil with native seeds; (2) inoculated with steam‐pasteurized soil with native seeds; (3) noninoculated with native seeds; or (4) noninoculated/nonseeded control. Inoculation with whole soil did not improve seed germination; however, addition of whole soil significantly improved native species survival, compared to pasteurized soil or noninoculated treatments. Inoculation with whole soil significantly decreased reestablishment of non‐native invasive Bothriochloa bladhii (Caucasian bluestem); at the end of the growing season, plots receiving whole soil consisted of approximately 30% B. bladhii cover, compared to approximately 80% in plots receiving no soil inoculum. Our results suggest invasion and eradication efforts negatively affect arbuscular mycorrhizal hyphal and spore abundances and soil aggregate stability, and inoculation with locally adapted soil microbial communities can improve metrics of restoration success, including plant species richness and diversity, while decreasing reinvasion by non‐native species.

Response of Chinese Tallow (Triadica sebifera) and Coexisting Natives to Competition, Shade, and Flooding

Abstract A greenhouse experiment was designed to determine the interactive effect of light, flooding, and competition on the growth and performance of Chinese tallow (Triadica sebifera [L.] Roxb.) and three tree species native to the southeastern United States: water tupelo (Nyssa aquatica L.), sugarberry (Celtis occidentalis L.), and green ash (Fraxinus pennsylvanica Marshall). The experiment used a factorial design that received two treatments: light (low irradiance or high irradiance) and flood (nonflooded and flooded) regimes. In the nonflooded and high irradiance treatment, changes in the growth (ground diameter, number of leaves, and total biomass) indicated that growth metrics of tallow were highest when growing with sugarberry and water tupelo but decreased when tallow was in competition with green ash. In contrast, competition with tallow reduced the height, net photosynthetic rate, stomatal conductance, and transpiration rate of water tupelo. The results showed that tallow had lower growth metrics when in competition with green ash at no apparent decrease in the growth of green ash except for growth rate. Our results suggest that tallow may be less competitive with certain native species and underplanting may be a possible opportunity for improving the success rates of native tree species establishment in areas prone to tallow invasion.

Native plants facilitate vegetation succession on amended and unamended mine tailings

Facilitating the establishment of native pioneer plant species on mine tailings with inherent metal and/or acid tolerance is important to speed up natural succession at minimal cost, especially in remote areas where phytoremediation can be labor intensive. We investigated vegetation community dynamics after ∼48 years of succession along two legacy Ni–Cu mine tailings and waste rock deposits in the Sudbury Basin, Ontario, Canada with and without various site amendments (i.e. liming and fertilization) and planting. Metal/acid tolerant pioneer plants (Betula papyrifera, Populus tremuloides, Pohlia nutans) appeared to facilitate the establishment of less tolerant species. Conifers and nitrogen-fixers less tolerant to site conditions were planted at the fully amended (limed, fertilized, planted) mine tailings site in the 1970s, but conifers were not propagating at the site or facilitating understory succession. The planted nitrogen-fixing leguminous species Lotus corniculatus was, however, associated with increased diversity. These findings have implications for long-term reclamation strategies in acidic mine waste deposits utilizing native species, as primary colonizing tree species are only recently emerging as candidates for phytoremediation. Novelty statement The potential for native species to act as facilitators for vegetation colonization has rarely been investigated on tailings, despite wide use in remediation of less toxic sites. This study provides a retrospective of over 40 years of plant growth following initial treatment of toxic tailings. We observed that regardless of tailings geochemical conditions, acid/metal tolerant pioneer plants were facilitating ecological succession on acidic Ni-Cu mine tailings sites.

Can locally sourced inoculum and biochar synergistically improve the establishment of mycorrhizal fungi in mine tailings?

The severely degraded soils at abandoned mine lands present several environmental challenges, including extreme pH, nutrient deficiency, and compaction, which can limit plant growth. Amending soils with biochar and/or mycorrhizal fungi may attenuate these constraints. However, the efficacy of amendments for improving the establishment of native plant species in restorations can be context dependent; pairing the right plant species with the right amendment is crucial to the success of restoration goals. In a greenhouse experiment, we evaluated the growth responses of two native plant species in soils collected from the Formosa Mine Superfund Site (Riddle, OR, U.S.A.). Seedlings of Elymus glaucus and Pseudotsuga menziesii were grown in tailings amended with biochar, locally collected rhizosphere soil containing a suite of soil microorganisms including mycorrhizal fungi, a combination of biochar and rhizosphere soil, or were unamended. We hypothesized that (1) individual amendments would increase plant biomass compared to controls and (2) that the co‐amended treatments would have a synergistic effect on plant growth. Instead, we detected no effect of rhizosphere soil or the co‐amendment on the growth of either plant species and found that biochar reduced the shoot biomass and leaf chlorophyll content of E. glaucus. Despite the lack of growth response, we observed significant rates of mycorrhizal colonization in the plants amended with local rhizosphere soil, demonstrating that locally sourced fungi can survive and proliferate in the amended Formosa tailings. Thus, inoculated seedlings of native plant species could provide essential ground cover and long‐term habitat for developing mycorrhizal communities in mine tailings.

Invasion theory as a management tool for increasing native biodiversity in urban ecosystems

Abstract Human activity has altered ecosystems in some places to a point where traditional restoration, ecosystem management and conservation interventions might not be feasible. This is especially true in densely populated urban areas if ongoing stressors are not ameliorated. As a result, different management options are needed for increasing native biodiversity and ecosystem function in novel urban ecosystems. One strategy for increasing biodiversity in urban ecosystems is to employ invasion biology theory to augment the establishment and proliferation of desirable native species. Invasion hypotheses, including fluctuating resources, enemy release, novel weapons, invasional meltdown (facilitation) and propagule pressure, all provide insights into the mechanisms that increase the establishment and spread of populations. These hypotheses point to specific interventions that can be used in urban restoration and management. Synthesis and applications. Viewing invasion mechanisms as a way to increase native biodiversity in novel urban ecosystems provides a useful reframing for assessing possible applications and management interventions for the most difficult‐to‐restore landscapes. We argue that conservation managers can use and test invasion hypotheses to inform biodiversity management practices in novel landscapes.

Using functional dissimilarity among species pools and communities to predict establishment of native and alien species

AbstractAimsPredicting plant establishment and growth is a fundamental goal of community ecology, especially when studying invasion. Functional traits can infer a species’ environmental tolerances and competitive abilities and may help improve predictions, yet such models are limited by a lack of data on failed establishment. Filtering of species from regional pools to site‐specific pools to local communities provides abundant evidence of failed establishment represented by species excluded at each level of the hierarchy. We tested whether trait differences between observed and absent species among these pools can help predict species establishment.LocationSouthern Estonia.MethodsFor 31 semi‐natural grassland sites, we collected plant composition data at multiple spatial scales to estimate the regional species pool, site‐specific pool, and local community. We compared traits among these pools to model community assembly and predict which species could join the site‐specific pool and local community. We tested these models using an experiment in which we added seed and transplants of 15 species (9 native and 6 alien) to intact and disturbed plots at each site. We considered differences in plant performance between intact and disturbed sites to be indicative of competition.ResultsFor all performance metrics, we found significant positive relationships with model predictions. These relationships were stronger for seed establishment than growth and were generally weak when predicting competition. Seed establishment was also best predicted in sites with high local diversity and low root biomass, potentially because of more accurate estimates of species pool and community composition. Seed establishment was better predicted for alien than native species and, although predictive power remained low, the opposite was true for competitive effects on establishment.ConclusionsMulti‐scale models of community assembly may predict future establishment but must include other characteristics within such models. These models may perform poorly, however, when predicting biotic interactions.

Anti-erosion rehabilitation: Effects of revegetation method and site traits on introduced and native plant cover and richness

In mountainous areas, bare slopes represent often dangerous forms of land degradation that need to be rehabilitated. However, revegetation is usually performed with non-native plants, negatively impacting the natural landscape value. Comprehensive studies, especially on poorly investigated long-term revegetation effects, are therefore essential for the improvement of rehabilitation practices.In this study, four landslides or disused quarries surrounded by well-preserved (semi-) natural vegetation that were revegetated between 1988 and 2002 with non-native only herbaceous or both herbaceous and woody plants were studied 1–9 and 16–31 years after rehabilitation. A total of 111 sampling areas were surveyed for introduced and volunteer species and other important ground cover soil and topography traits. Climatic traits and species' ecological indicators were retrieved from the available databases. The time patterns and ecological spectra of the plant covers were analysed and correlated to the site traits.In the first decade, introduced plants were initially abundant but decreased rapidly. In the long-term, the more stress-tolerant among them still had a considerable cover, especially in fine-textured soils. Native species were established slowly but, due to their higher stress tolerance, dominated in the long-term, especially at more stressful sites.In areas with predominantly herbaceous cover, soil factors, such as gravel content, were more related to the plant cover. In areas with predominantly woody plant cover, the high plant cover was dependent on microclimatic factors, especially aspect.At sites like those studied here, woody species should be always used, but in the form of native plants, as they tend to persist. If herbaceous species are unavailable in native forms, their introduction should be avoided in areas not exposed to erosion, whereas poorly stress-tolerant non-native plants should be used in steep areas as they create a fast but short-lasting cover compensated in the long term by the establishment of native species.