Aboveground and Belowground Impacts Following Removal of the Invasive Species Baby's Breath (Gypsophila paniculata) on Lake Michigan Sand Dunes

The removal of invasive species is often one of the first steps in restoring degraded habitats. However, studies evaluating effectiveness of invasive species removal are often limited in spatial and temporal scale, and lack evaluation of both aboveground and belowground effects on diversity and key processes. In this study, we present results of a large 3‐year removal effort of the invasive species, Gypsophila paniculata, on sand dunes in northwest Michigan (USA). We measured G. paniculata abundance, plant species richness, plant community diversity, non‐native plant cover, abundance of Cirsium pitcheri (a federally threatened species endemic to this habitat), sand movement, arbuscular mycorrhizal spore abundance, and soil nutrients in fifteen 1000 m² plots yearly from 2007 to 2010 in order to evaluate the effectiveness of manual removal of this species on dune restoration. Gypsophila paniculata cover was greatly reduced by management, but was not entirely eliminated from the area. Removal of G. paniculata shifted plant community composition to more closely resemble target reference plant communities but had no effect on total plant diversity, C. pitcheri abundance, or other non‐native plant cover. Soil properties were generally unaffected by G. paniculata invasion or removal. The outlook is good for this restoration, as other non‐native species do not appear to be staging a “secondary” invasion of this habitat. However, the successional nature of sand dunes means that they are already highly invasible, stressing the need for regular monitoring to ensure that restoration progresses.     

Ecological Assessment of Dune Restorations in the Great Lakes Region

Because of the economic and environmental importance of stabilizing fragile sand dune habitats, restoration of dunes has become a common practice. Restoration efforts in the Great Lakes and East Coast regions of North America often consist of planting monocultures of the dominant native grass species, Ammophila breviligulata. We evaluated 18 dune restoration projects in the Great Lakes region conducted over the past 25 years. We characterized attributes of diversity (plants and insects), vegetation structure (plant biomass and cover), and ecological processes (soil nutrients and mycorrhizal fungi abundance) in each restoration, and we compared these measures to geographically paired natural dune communities. Restoration sites were similar to reference sites in most measured variables. Differences between restorations and reference sites were mostly explained by differences in ages, with the younger sites supporting slightly lower plant diversity and mycorrhizal spore abundance than older sites. Plant community composition varied little between restored and reference sites, with only one native forb species, Artemisia campestris, occurring significantly more often in reference sites than restored sites. Although it remains unclear whether more diverse restoration plantings could accelerate convergence on the ecological conditions of reference dunes, in general, traditional restoration efforts involving monoculture plantings of A. breviligulata in Great Lakes sand dunes appear to achieve ecological conditions found in reference dunes.     

Impacts of management and antecedent site condition on restoration outcomes in a sand prairie

Landscape context and site history, including antecedent site conditions, may constrain restoration potential despite the efforts of restoration practitioners. However, few experimental studies have investigated the relative importance of antecedent site conditions and the intensity of on‐site management in driving restoration outcomes. We established small‐scale prairie restoration experiments within the Lost Mound Unit of the Upper Mississippi River National Wildlife and Fish Refuge in Illinois, U.S.A. We investigated the effectiveness of two restoration treatments, herbicide application and seeding of native plants, on removal of invasive crown‐vetch (Securigera varia) and recovery of sand prairie plant communities. We replicated treatment plots across 15 locations with three levels of antecedent condition and fire treatment (burned, undegraded; burned, degraded; and unburned, degraded) to determine whether antecedent condition constrained the effectiveness of on‐site restoration. Two years after initial herbicide application crown‐vetch cover was significantly reduced relative to untreated controls. This effect was more pronounced in plots treated twice with herbicide. However, removal of crown‐vetch facilitated invasion by Kentucky bluegrass (Poa pratensis). Addition of native prairie seed had little effect on restoration outcomes, regardless of herbicide application. Native community recovery was greater in plots restored in less degraded locations. Herbicide application tended to increase native species cover, but importantly, this effect was significant only in the least degraded locations. Intensive restoration management conducted in degraded landscapes can result in undesirable outcomes such as secondary species invasion. Reestablishment of native species following restoration is more likely where the surrounding remnant communities are intact.     

Soil microbial communities in restored and unrestored coastal dune ecosystems in California

Most restoration projects involving invasive plant eradication tend to focus on plant removal with little consideration given to how these invasives change soil microbial communities. However, soil microorganisms can determine invasibility of habitats and, in turn, be altered by invasives once established, potentially inhibiting native plant establishment. We studied soil microbial communities in coastal dunes with varying invasion intensity and different restoration approaches (herbicide, mechanical excavation) at Point Reyes National Seashore. Overall, we found evidence of a strong link between bacterial and fungal soil communities and the presence of invasives and restoration approach. Heavily invaded sites were characterized by a lower abundance of putatively identified nitrifiers, fermentative bacteria, fungal parasites, and fungal dung saprotrophs and a higher abundance of cellulolytic bacteria and a class of arbuscular mycorrhizal fungi (Archaeosporomycetes). Changes in soil microbiota did not fully dissipate following removal of invasives using herbicide, with exception of reductions in cellulolytic bacteria and Archaeosporomycetes abundance. Mechanical restoration effectively removed both invasives and soil legacy effects by inverting or “flipping” rhizome‐contaminated surface soils with soils from below and may have inadvertently induced other adverse effects on soils that impeded reestablishment of native dune plants. Land managers should consider additional measures to counteract lingering legacy effects and/or focus restoration efforts in areas where legacy effects are less pronounced.     

Positive responses of coastal dune plants to soil conditioning by the invasive Lupinus nootkatensis

Invasive nitrogen-fixing plants drive vegetation dynamics and may cause irreversible changes in nutrient-limited ecosystems through increased soil resources. We studied how soil conditioning by the invasive alien Lupinus nootkatensis affected the seedling growth of co-occurring native plant species in coastal dunes, and whether responses to lupin-conditioned soil could be explained by fertilisation effects interacting with specific ecological strategies of the native dune species. Seedling performance of dune species was compared in a greenhouse experiment using field-collected soil from within or outside coastal lupin stands. In associated experiments, we quantified the response to nutrient supply of each species and tested how addition of specific nutrients affected growth of the native grass Festuca arundinacea in control and lupin-conditioned soil. We found that lupin-conditioned soil increased seedling biomass in 30 out of 32 native species; the conditioned soil also had a positive effect on seedling biomass of the invasive lupin itself. Increased phosphorus mobilisation by lupins was the major factor driving these positive seedling responses, based both on growth responses to addition of specific elements and analyses of plant available soil nutrients. There were large differences in growth responses to lupin-conditioned soil among species, but they were unrelated to selected autecological indicators or plant strategies. We conclude that Lupinus nootkatensis removes the phosphorus limitation for growth of native plants in coastal dunes, and that it increases cycling of other nutrients, promoting the growth of its own seedlings and a wide range of dune species. Finally, our study indicates that there are no negative soil legacies that prevent re-establishment of native plant species after removal of lupins.     

Recovery of Foredune and Blowout Habitats in a Freshwater Dune Following Removal of Invasive Austrian Pine (Pinus nigra)

Invasive species removal is an important first step toward restoring invaded ecosystems; however, restoration following removal may be hindered by (1) unintended consequences of management, such as habitat destabilization, and/or (2) legacy effects of the invader, such as persistent alterations of soil structure or plant community composition. During 1956–1972, approximately 26,000 individuals of the non‐native pine, Pinus nigra, were planted into multiple freshwater sand dune habitats as a stabilization measure on the eastern shore of Lake Michigan in Allegan County, MI, U.S.A. From 2004 to 2010, we evaluated the recovery of foredune and blowout habitats following P. nigra removal in 2003–2005. We compared sand movement and plant community structure, composition, and richness between removal and control sites over the 6 years following pine removal. In addition, we evaluated the impact of litter removal on recolonization of native graminoids in foredunes. Sand movement patterns never differed between removal and control sites in foredunes; however, accumulation was more common in removal sites in blowouts 1 and 6 years following pine removal. Vegetation cover in removal sites became indistinguishable from control sites in both foredunes and blowouts, but species richness for both forb and woody species was higher in removal sites in blowouts. Removal sites in both foredunes and blowouts had higher cover by forbs and lower cover by graminoids. Pine litter did not inhibit recolonization of foredunes by native graminoids. These results suggest that high disturbance habitats, such as sand dunes, have the potential to recover from invasion if the mechanism of disturbance is restored and pioneer species are present to recolonize the system.     

Restoration of riverine inland sand dune complexes: implications for the conservation of wild bees

1.  The evaluation of restoration measures is an important task of conservation biology. Inland sand dunes and dry, oligotrophic grasslands have become rare habitat types in large parts of Central Europe and their restoration and management is of major importance for the preservation of many endangered plant and insect species. Within such habitats, it is important to restore key ecosystem services, such as pollination networks. As wild bees are the most important pollinators in many ecosystems, they represent a suitable key group to evaluate restoration measures. Furthermore, the recent decline of many bee species and the potential ecological and economic consequences are currently topics of strong scientific interest.
2.  We studied the succession of bee communities in response to restoration measures of sand dunes and sand grasslands and compared these communities with those of old sand dune complexes.
3.  Our results show that wild bees respond rapidly to restoration measures indicated by a high species richness and abundance. The community structure of bees at restoration sites converged only slightly to those of the target sites. A higher similarity was found between bee communities at the restoration sites (sand dunes and grasslands), indicating that their close proximity was an important determinant of species overlap. Environmental factors such as the number of entomophilous plant species and moisture had a strong influence on wild bee species composition.
4.   Synthesis and applications . The restoration of inland sand dune complexes provides opportunities for colonization by a diverse wild bee community. Although it is difficult to establish a given target community, restoration measures gave rise to a high pollinator diversity and abundance, suggesting that community function can be re-established.     

Are some communities of the coastal dune zonation more susceptible to alien plant invasion?

Aims Coastal areas, and in particular coastal dunes, are ecosystems strongly affected by the invasion of alien plants. However, few attempts have ever been made to quantify alien species incidence in different communities along the coastal zonation. This work aims to analyze the distribution of alien plants along the coastal zonation of sandy shores on the Tyrrhenian coast, addressing specifically differences among plant communities in abundance of alien plants.Methods The study was performed on recent dunes (Holocene) of the central western coast of Italy. We selected dune landscapes where invasion processes were particularly evident. Vegetation plots were randomly sampled and through cluster analysis, we identified six plant communities corresponding to the typical zonation described for the Tyrrhenian sandy coast of Central Italy. We evaluated and compared frequency and abundance of invasion in these different communities. Further, we investigated how propagule pressure (measured using as proxy human structures) contributed to the observed invasion patterns.Important findings We found a relatively low total number of aliens but also a differential distribution pattern and strong abundance of some of the aliens in specific sectors of the vegetation zonation. The perennial community of transition dunes appears most affected by invasion processes, related almost exclusively to the frequent and widespread Carpobrotus aff. acinaciformis. This alien species reaches high cover values, apparently lowering cover of native species of transition dune plant communities. Higher levels of invasion in the transition dune can be partially explained because of greater propagule pressure in this section of the dune profile. Our findings thus have important conservation and management implications since transition dune communities with Crucianella maritima are rare and protected (sensu Habitat 92/43/EEC Directive) along the entire Italian coast.     

Restoring native understory to a woodland invaded by Euonymus fortunei: multiple factors affect success

Invasive species are capable of causing change in native plant communities, but invasion is often associated with other anthropogenic impacts on natural areas, such as habitat fragmentation and associated dispersal limitation for native species. Consequently, invasive species removal alone may not always be sufficient to meet restoration objectives. We tested if invasion and dispersal limitation interact to limit plant community restoration within a forest fragment invaded by Euonymus fortunei. Removal of Euonymus alone did not lead to the recolonization of native plant species. However, planting seedlings increased total native cover in invaded, Euonymus removal, and uninvaded control treatments. The consistent establishment of native plant seedlings across all treatments indicates that Euonymus invasion may have limited ability to displace established plants. In contrast, plant species that we added as seed were unable to establish in invaded plots, indicating that Euonymus invasion limits recruitment of native plant species from seed. Over the course of our experiment, a number of setbacks and surprises occurred, including high levels of herbivory, a windstorm, and extreme drought, all of which likely limited restoration success. Overall, our results indicate that Euonymus may contribute to native species declines, but other factors are important. Thus, invasive species removal alone may not be sufficient to reestablish a diverse native plant community. Instead, impacts on natural areas may need to be mitigated along with invasive species removal for restoration to be successful.     

Long-Term Ecosystem Effects of Sand-Binding Vegetation in the Tengger Desert, Northern China

The planting of sand‐binding vegetation in the Shapotou region at the southeastern edge of the Tengger Desert began in 1956. Over the past 46 years, it has not only insured the smooth operation of the Baotou–Lanzhou railway in the sand dune section but has also played an important role in the restoration of the local eco‐environment; therefore, it is viewed as a successful model for desertification control and ecological restoration along the transport line in the arid desert region of China. Long‐term monitoring and focused research show that within 4–5 years of establishment of sand‐binding vegetation, the physical surface structure of the sand dunes stabilized, and inorganic soil crusts formed by atmospheric dust gradually turned into microbiotic crusts. Among the organisms comprising these crusts are cryptogams such as desert algae and mosses. In the 46 years since establishing sand‐binding vegetation, some 24 algal species occurred in the crusts. However, only five moss species were identified, which was fewer than the species number in the crust of naturally fixed sand dunes. Other results of the planting were that near‐surface wind velocity in the 46‐year‐old vegetation area was reduced by 54.2% compared with that in the moving sand area; soil organic matter increased from 0.06% in moving sand dunes to 1.34% in the 46‐year‐old vegetation area; the main nutrients N, P, K, etc., in the desert ecosystem increased; soil physicochemical properties improved; and soil‐forming processes occurred in the dune surface layer. Overall, establishment of sand‐binding vegetation significantly impacted soil water cycles, creating favorable conditions for colonization by many herbaceous species. These herbaceous species, in turn, facilitated the colonization and persistence of birds, insects, soil animals, and desert animals. Forty‐six years later, some 28 bird species and 50 insect species were identified in the vegetated dune field. Thus, establishment of a relatively simple community of sand‐binding species led to the transformation of the relatively barren dune environment into a desert ecosystem with complex structure, composition, and function. This restoration effort shows the potential for short‐term manipulation of environmental variables (i.e., plant cover via artificial vegetation establishment) to begin the long‐term process of ecological restoration, particularly in arid climates, and demonstrates several techniques that can be used to scientifically monitor progress in large‐scale restoration projects.     

Effects of long‐term grazing management on sand dune vegetation of high conservation interest

Question: Can long‐term grazing management maintain and restore species‐rich sand dune plant communities within a sand dune site of high conservation interest? Location: Newborough Warren, North Wales, UK. Methods: Vegetation changes that occurred between 1987 and 2003, subsequent to grazing by domestic livestock being introduced to the site after decades with little or no stock grazing, were analysed using data collected from permanent monitoring quadrats over a 16‐year period. Results: At the plant community level, grazing brought about a shift from a tall‐grass dominated, species‐poor community to a more species‐rich community in the dry dunes, but did not change community type in dune slacks. However, at the species level, grazing enhanced the abundance of some desired perennial, annual and biennial species, graminoids and bryophytes in both habitat types. The increased frequency of positive indicator species for habitat condition suggests that grazing was beneficial for species of conservation interest. Ellenberg nitrogen (N) values decreased after grazing in dry habitats but showed no long‐term change independent of grazing, suggesting no increase in site fertility over the study period. Surprisingly, light (L) values also decreased in the dry dunes after grazing. Conclusions: Long‐term grazing management can play an important role for the conservation of dune communities and associated species. Because of its positive effects on species diversity, plant communities and habitat condition in sand dunes, livestock grazing is recommended for conservation management.     

Responses to invasion and invader removal differ between native and exotic plant groups in a coastal dune

The spread of exotic, invasive species is a global phenomenon that is recognized as a major source of environmental change. Although many studies have addressed the effects of exotic plants on the communities they invade, few have quantified the effects of invader removal on plant communities, or considered the degree to which different plant groups vary in response to invasion and invader removal. We evaluated the effects of an exotic succulent, iceplant (Carpobrotus edulis), on a coastal dune plant community in northern California, as well as the community responses to its removal. To assess possible mechanisms by which iceplant affects other plants, we also evaluated its above- and belowground influences on the germination and growth of a dominant exotic annual grass, Bromus diandrus. We found that iceplant invasion was associated with reduced native plant cover as well as increased cover and density of some exotic plants—especially exotic annual grasses. However, iceplant removal did not necessarily lead to a reversal of these effects: removal increased the cover and density of both native and exotic species. We also found that B. diandrus grown in iceplant patches, or in soil where iceplant had been removed, had poorer germination and growth than B. diandrus grown in soil not influenced by iceplant. This suggests that the influence of iceplant on this dune plant community occurs, at least in part, due to belowground effects, and that these effects remain after iceplant has been removed. Our study demonstrates the importance of considering how exotic invasive plants affect not only native species, but also co-occurring exotic taxa. It also shows that combining observational studies with removal experiments can lead to important insights into the influence of invaders and the mechanisms of their effects.     

Response to soil biota by native, introduced non-pest, and pest grass species: is responsiveness a mechanism for invasion?

Soil biota have been credited with helping to maintain native plant diversity in multiple systems. Recent evidence suggests that introduced species may be less responsive to soil communities than most native species. If response to soil communities is correlated with invasive ability, we predict that introduced pest species should be less responsive to soil communities than introduced non-pest species or natives. In this study we test whether response to soil biota from two diverse grassland communities differs between four introduced pest, six introduced non-pest, and five native species in grasses in Yolo County, California. We found no variation in plant size or response to soil biota between introduced pest and introduced non-pest species, and these were combined in subsequent analyses. Overall, all introduced species grew significantly faster than native species. Native species showed greater variation in response to soil communities than both groups of introduced species, and native species’ response varied with soil community. Variation among native species’ response to soil nutrients and biota through processes like soil feedbacks may be key to maintaining diversity across landscapes in uninvaded environments. Introduced species appear less responsive to landscape variability in soil communities, which may allow them to establish and dominate plant communities in multiple habitats.     

If you build it,will they come? Use of restored dunes by beach mice

Restoration of coastal habitat fragmented, degraded, or destroyed by development and climate‐related processes such as sea level rise and storm surge usually involves planting native plants to restore habitat structure, but whether and how restored areas benefit taxa other than plants is rarely reported. Installing restoration plantings is one method used to build habitat such as beach dunes where dunes have been lost, potentially creating habitat for dune‐dependent species. We compared use of natural vegetated dunes, open sand gaps, and restoration plantings (habitat treatment) by Perdido Key beach mice (Peromyscus polionotus trissyllepsis) over 3 years using tracking tubes to assess the value of restoration plantings for beach mice. Tubes were monitored in two seasons (early and mid‐summer), and under new and full moon conditions. Mice used restoration plantings less than natural vegetated dunes but more than open sand gaps, which suggests restoration plantings may facilitate movement of mice across fragmented areas. Both season and moon phase influenced the effect of habitat treatment, interactions which may be attributable to perceived risk associated with movement under a combination of different conditions of ambient light, vegetation cover, and habitat novelty. Our results show restoration plantings provide habitat for movement and foraging, and may ameliorate some consequences of sea level rise and storms for beach mice and potentially other dune‐dependent species into the future.     

Mesophilic Actinomycetes in the Natural and Reconstructed Sand Dune Vegetation Zones of Fraser Island, Australia

The natural coastal habitat of Fraser Island located in the State of Queensland, Australia, has been disturbed in the past for mining of the mineral sand ilmenite. Currently, there is no information available on whether these past mining disturbances have affected the distribution, diversity, and survival of beneficial soil microorganisms in the sand dunes of the island. This in turn could deleteriously affect the success of the natural regeneration, plant growth, and establishment on the sand dunes. To support ongoing restoration efforts at sites like these mesophilic actinomycetes were isolated using conventional techniques, with particular emphasis on the taxa previously reported to produce plant-growth-promoting substances and providing support to mycorrhizal fungi, were studied at disturbed sites and compared with natural sites. In the natural sites, foredunes contained higher densities of micromonosporae replaced by increasing numbers of streptomycete species in the successional dune and finally leading to complex actinomycete communities in the mature hind dunes. Whereas in the disturbed zones affected by previous mining activities, which are currently being rehabilitated, no culturable actinomycete communities were detected. These findings suggest that the paucity of beneficial microflora in the rehabilitated sand dunes may be limiting the successful colonization by pioneer plant species. Failure to establish a cover of plant species would result in the mature hind dune plants being exposed to harsh salt and climatic conditions. This could exacerbate the incidence of wind erosion, resulting in the destabilization of well-defined and vegetated successional dunal zones.     

Invasive species cover,soil type,and grazing interact to predict long‐term grassland restoration success

Grasslands are undergoing tremendous degradation as a result of climate change, land use, and invasion by non‐native plants. However, understanding of the factors responsible for driving reestablishment of grassland plant communities is largely derived from short‐term studies. In order to develop an understanding of the factors responsible for longer term restoration outcomes in California annual grasslands, we surveyed 12 fields in Davis, CA, U.S.A., in 2015 that were seeded with native species mixtures starting in 2004. Using field surveys, we investigated how invasive plant richness and cover, native plant richness and cover, aboveground biomass, grazing, soil type, and restoration species identity might provide utility for explaining patterns of restoration success. We found a negative relationship between invasive cover and restoration cover, which was attributed to the slow establishment of seeded species and subsequent dominance by weeds. The relationship between invasive cover and restoration cover was modified by grazing, likely due to a change in the dominance of exotic forbs, which have a more similar growing season to restoration species, and therefore compete more strongly for late season moisture. Finally, we found that soil type was responsible for differences in the identity and abundance of invasive plants, subsequently affecting restoration cover. This work highlights the value of focusing resources on reducing invasive species cover, limiting grazing to periods of adequate moisture, and considering soil type for successful long‐term restoration in California annual grasslands. Moreover, observations of long‐term restoration outcomes can provide insight into the way mechanisms driving restoration outcomes might differ through time.     

Invasive legume management strategies differentially impact mutualist abundance and benefit to native and invasive hosts

Determining the best management practices for plant invasions is a critical, but often elusive goal. Invasive removals frequently involve complex and poorly understood biotic interactions. For example, invasive species can leave potent legacies that influence the success of native species restoration efforts, and positive plant‐microbial feedbacks may promote continued reinvasion by an exotic species following restoration. Removal methods can vary in their effects on plant–soil feedbacks, with consequences for restoration of native species. We determined the effects of invasion by a leguminous shrub (French broom; Genista monspessulana) on the density and community composition of, and benefit conferred by, its microbial mutualists in its invading range. Densities of soil‐dwelling rhizobia were much higher in areas invaded by G. monspessulana relative to uninvaded areas, and this increased density of rhizobia fed back to increase seedling growth of both the invader and native legumes. We further compared how three techniques for removing G. monspessulana affected the densities of rhizobia relative to areas where G. monspessulana was still present. Removal by hand‐pulling reduced soil rhizobial densities, and reduced growth of one native legume, while having no effect on the growth of the invader. Overall, our results show that the consequences of restoration techniques, both above‐ and belowground, could be critical for the successful removal of an invasive legume and restoration of native species.     

The sand dune vegetation of Chrystalls Beach, southern New Zealand, with particular reference to the cushion community

The sand dune system at Chrystalls Beach, New Zealand comprises front dune, dune hollow and rear dune areas. On the front dunes are two communities: one on the seaward face of the dunes, and another on the landward face. Most of the dune hollow is occupied by a series of grassland communities, but there are areas of a distinctive cushion community, still largely native in its species composition. It is suggested that the cushion community is maintained against invasion by a switch, possibly involving sand grain size, soil organic content, water supply, wind and magnesium:calcium ratio. The coarse sandy/pebbly substrate, with its low organic content, causes water stress. The water stress permits only low vegetation, which exacerbates the low soil organic content. The low vegetation results in high wind, again favouring cushion species. The water regime has also allowed a buildup of Mg:Ca ratio, especially in the lower layers of the soil.     

Understanding plant drought resistance in a Mediterranean coastal sand dune ecosystem: differences between native and exotic invasive species

Aims Mediterranean coastal dunes are habitats of great conservation interest, with a distinctive and rich flora. In the last century, Acacia spp., native from Australia, have been introduced in Portugal, with the objective of stabilizing sand dunes, and since have become dominant in numerous sand dune habitats. This invasion process led to the reduction of native plant species richness, changed soil characteristics and modified habitat's microclimatic characteristics. The aim of this research was to typify and compare, in Mediterranean sand dune ecosystems, the ecophysiological responses to drought of Helichrysum italicum and Corema album, two native species, and Acacia longifolia, an exotic invasive species. We addressed the following specific objectives: (i) to compare water relations and water use efficiencies, (ii) to evaluate water stress, (iii) to assess water use strategies and water sources used by plants and (iv) to evaluate the morphological adaptations at leaf and phyllode level. Methods In order to obtain an integrative view of ecophysiological patterns, water relations and performance measuring methods have been applied: predawn (ψ PD) and midday (ψ MD) water potential, chlorophyll a fluorescence, oxygen isotopic composition of xylem, rain and groundwater (δ 18 O) and leaf carbon isotopic discrimination (Δ 13 C). The leaf characteristics of the three species, as well as the histochemistry of non-glandular trichome cell walls, were also studied to identify morpho-traits related to drought resistance.Important findings The results support our initial hypothesis: although A. longifolia clearly possesses a degree of resistance to water stress, such ability is provided by a different water strategy, when compared to native species. Natives relied on morphological adaptations to restrict water loss, whereas the invasive species adjusted the water uptake as a way to balance their limited ability of restricting water loss. We corroborate that woody native species (i) have a conservative water-saving strategy and minor seasonal variations relative to invasive species, (ii) use enriched water sources during drought periods, indicating different water sources and root systems comparing with invasive species and (iii) present drought leaf morpho-functional adaptations related with limiting water loss. Comparing the physiological performance of invasive and native species can offer causal explanations for the relative success of alien plant invasions on sand dunes ecosystems.     

Soil pH influences patterns of plant community composition after restoration with native‐based seed mixes

Reclamation of highly disturbed lands typically includes establishing fast‐growing, non‐native plants to achieve rapid ground cover for erosion control. Establishing native plant communities could achieve ecosystem functions beyond soil erosion, such as providing wildlife habitat. Pipelines, or other disturbed corridors through a landscape, present unique challenges for establishing native plant communities given the heterogeneity of soil environments and invasive plant propagule pressure. We created two structural equation models to address multiple related hypotheses about the influence of soil pH on plant community composition (current diversity and vegetative cover of the original restoration seed mix and background flora, and invasive plant density during mix establishment and current density) of a highly disturbed landscape corridor restored with native species. To test our hypotheses we conducted a plant survey on a gas pipeline crossing two state forests in the north‐central Appalachians that had been seeded with a native‐based mixture 8 years prior. Low soil pH was a strong predictor of density of the invasive annual plant, Microstegium vimineum, and had resulted in lower species diversity and cover of the seeded mix. Overall, our data provide evidence that native‐based grass and forb mixtures can establish and persist on a wide range of soil environments and thrive in competition with invasive plants in moderately acidic to neutral soils. Advancing knowledge on restoration methods using native species is essential to improving restoration practice norms to incorporate multifunctional ecological goals.