Tree Robinia Pseudoacacia Research Articles

Spatial genetic structure of the invasive tree Robinia pseudoacacia to determine migration patterns to inform best practices for riparian restoration.

The black locust Robinia pseudoacacia (Robinieae, Fabaceae) is a common invasive riparian tree in Japan. There are less effective management strategies to remove the tree from the riparian area because of its quickly established high population. We investigated the expansion patterns of R. pseudoacacia through sympatric (i.e. between high- and low-water channel (HWC/LWC) within a study site) and allopatric (i.e. along river corridor) dispersal in the Tama River (Tokyo, Japan). Four microsatellites were used to examine the effects of gene flow on six populations in three sites. These subpopulations showed small genetic distance (i.e. no barrier or slightly limited) and genetically mixed population structure. It indicated that both sympatric and allopatric dispersals were active. Many migrants were younger individuals (i.e. <5 years old) and were found in the LWC area. Thus, the LWC could receive more migrants than the HWC through both types of dispersals. In addition, our age and genetic structure analyses reveal that recruited individuals likely settled immediately after the clearing project of R. pseudoacacia through sympatric dispersal. It appears that the migration by allopatric dispersal occurred following this. For the effective management of R. pseudoacacia, migrants should be removed regularly following initial removal of invaders during site restoration.

Range shifts of native and invasive trees exacerbate the impact of climate change on epiphyte distribution: The case of lung lichen and black locust in Italy

While changing climatic conditions may directly impact species distribution ranges, indirect effects related to altered biotic interactions may exacerbate range shifts. This situation fully applies to epiphytic lichens that are sensitive to climatic factors and strongly depend on substrate occurrence and features for their dispersal and establishment. In this work, we modelled the climatic suitability across Italy under current and future climate of the forest species Lobaria pulmonaria, the lung lichen. Comparatively, we modelled the suitability of its main tree species in Italy, as well as that of the alien tree Robinia pseudoacacia, black locust, whose spread may cause the decline of many forest lichen species. Our results support the view that climate change may cause range shifts of epiphytes by altering the spatial pattern of their climatic suitability (direct effect) and simultaneously causing range shifts of their host-tree species (indirect effect). This phenomenon seems to be emphasized by the invasion of alien trees, as in the case of black locust, that may replace native host tree species. Results indicate that a reduction of the habitat suitability of the lung lichen across Italy should be expected in the face of climate change and that this is coupled with a loss of suitable substrate. This situation seems to be determined by two main processes that act simultaneously: 1) a partial reduction of the spatial overlap between the climatic niche of the lung lichen and that of its host tree species, and 2) the invasion of native woods by black locust. The case of lung lichen and black locust in Italy highlights that epiphytes are prone to both direct and indirect effects of climate change. The invasion of alien trees may have consequences that are still poorly evaluated for epiphytes.

Drought sensitivity of an N2 -fixing tree may slow temperate deciduous forest recovery from disturbance.

Increased drought intensity and frequency due to climate change may reduce the abundance and activity of nitrogen (N2 )-fixing plants, which supply new N to terrestrial ecosystems. As a result, drought may indirectly reduce ecosystem productivity through its effect on the N cycle. Here, we manipulated growing season net rainfall across a series of plots in an early successional mesic deciduous forest to understand how drought affects the aboveground productivity of the N2 -fixing tree Robinia pseudoacacia and three co-occurring nonfixing tree species. We found that lower soil moisture was associated with reduced productivity of R.pseudoacacia but not of nonfixing trees. As a result, the relative biomass and density of R.pseudoacacia declined in drier soils over time. Greater aboveground biomass of R.pseudoacacia was also associated with greater total soil N, extractable inorganic N, N mineralization rates, and productivity of nonfixing trees. These soil N effects may reflect current N2 fixation by R.pseudoacacia saplings, or the legacy effect of former trees in the same location. Our results suggest that R.pseudoacacia promotes the growth of nonfixing trees in early succession through its effect on the N cycle. However, the sensitivity of R.pseudoacacia to dry soils may reduce N2 fixation under scenarios of increasing drought intensity and frequency, demonstrating a mechanism by which drought may indirectly diminish potential forest productivity and recovery rate from disturbance.

Differences in the community composition of nocturnal Lepidoptera between native and invaded forests are linked to the habitat structure

Non-native invasive plants are among the main threats to global biodiversity, including insects, and it is thus important to understand the mechanisms of how invasive plants impact native species. The community composition of nocturnal Lepidoptera was studied in the Czech Republic (Central Europe) in stands of native deciduous trees and in stands dominated by the invasive tree Robinia pseudoacacia, using automatic portable light traps together with an assessment of habitat characteristics. Native stands had more closed canopies and poorly developed understories. Conversely, R. pseudoacacia stands were more open and heterogeneous, with sparse canopies, well-developed shrub layers and a higher cover of taller herbs. Moth species richness, abundance and biomass were lower in R. pseudoacacia, likely due to the low richness of canopy herbivores not adapted to feed on the exotic host. However, feeding guilds associated with the understorey were more represented in stands of R. pseudoacacia, likely due to the more heterogeneous habitat structure. The Lepidopteran communities observed in stands of R. pseudoacacia resembled communities of open-forests or forest-steppe habitats. In contrast, native stands were dominated by Lepidoptera associated with trees, including forest specialists but also habitat generalists. From a conservation perspective, it appears that the invasive R. pseudoacacia created structurally more heterogeneous environment and more Lepidopteran open-forest guilds were associated with this habitat. However, further spread of R. pseudoacacia should be prevented because it reduces the species richness of Lepidoptera. Simultaneously, we recommend increasing the habitat heterogeneity of native forests to support functionally more diverse Lepidopteran communities.

No evidence for genetic differentiation in juvenile traits between Belgian and French populations of the invasive tree Robinia pseudoacacia

Background – The role of evolution in biological invasion studies is often overlooked. In order to evaluate the evolutionary mechanisms behind invasiveness, both quantitative and population genetics studies are underway on Robinia pseudoacacia L., one of the worst invasive tree species in Europe.Methods – A controlled experiment was set up using 2000 seeds from ten populations in Southern France and ten populations in Belgium. Seedlings were cultivated in two climatic chambers set at 18°C and 22°C. Early development life history traits (e.g. seedling phenology) and functional traits (e.g. growth rates) were monitored. Genotyping using SNP markers was used to evaluate the genetic differentiation among the populations and a QST – FST comparison was done in order to test for the role of selection.Results – Populations exhibited a strong plasticity to temperature for all measured traits, the warmer environment being generally more suitable, irrespective of their origin. No significant departure from neutral evolution was evidenced by the QST – FST comparisons, although we found a slightly significant differentiation at the molecular level. Conclusion – Plasticity for the functional and life history traits was evidenced but no genetic interaction suggesting no possible evolution of plasticity at those traits. Moreover, no support for genetic differentiation and local adaptation was found among studied populations within invasive range, raising two main questions: first, what is the role of selection on functional and life-history traits; and second, is the elapsed time since first introduction sufficient to allow evolution and local adaptation?

How ecosystems change following invasion by Robinia pseudoacacia: Insights from soil chemical properties and soil microbial, nematode, microarthropod and plant communities

Biological invasions are a global threat to biodiversity. Since the spread of invasive alien plants may have many impacts, an integrated approach, assessing effects across various ecosystem components, is needed for a correct understanding of the invasion process and its consequences. The nitrogen-fixing tree Robinia pseudoacacia (black locust) is a major invasive species worldwide and is used in forestry production. While its effects on plant communities and soils are well known, there have been few studies on soil fauna and microbes.We investigated the impacts of the tree on several ecosystem components, using a multi-trophic approach to combine evidence of soil chemical properties and soil microbial, nematode, microarthropod and plant communities. We sampled soil and vegetation in managed forests, comparing those dominated by black locust with native deciduous oak stands.We found qualitative and quantitative changes in all components analysed, such as the well-known soil nitrification and acidification in stands invaded by black locust. Bacterial richness was the only component favoured by the invasion. On the contrary, abundance and richness of microarthropods, richness of nematodes, and richness and diversity of plant communities decreased significantly in invaded stands. The invasion process caused a compositional shift in all studied biotic communities and in relationships between the different ecosystem components.We obtained clear insights into the effects of invasion of managed native forests by black locust. Our data confirms that the alien species transforms several ecosystem components, modifying the plant-soil community and affecting biodiversity at different levels. Correct management of this aggressive invader in temperate forests is urgently required.

Molecular and morphological data confirmed the presence of the rare species Mattirolomyces terfezioides in China

Although the species Mattirolomyces terfezioides (≡ Terfezia terfezioides) has been recorded from China several times but it is really rare taxon with important ecological and economic value, the conspecificity with European material has never been tested by molecular data. We re-examined three specimens labelled as T. terfezioides, one as T. leonis and one as Terfezia sp. in the herbarium HMAS and obtained five ITS and three LSU sequences. Our morphological observation and DNA sequences show that one specimen (HMAS 83766) labelled as M. terfezioides turns out to be Choiromyces sp. and the other four are M. terfezioides. The ITS and (or) LSU sequences of the Chinese samples are identical with or with 99% similarity to those from the European samples, which fully confirms the presence of M. terfezioides in China. The species is currently known from northern China (Hebei Province, Beijing and Shanxi Province). This study shows that M. terfezioides has a Euroasia distribution other than European endemism and such distribution might be explained by the co-occurrence with the potential host tree Robinia pseudoacacia.

Robinia pseudoacacia as a surrogate for native tree species for saproxylic beetles inhabiting the riparian mixed forests of northern Italy

Abstract The felling and leaving of non‐native trees comprise management strategies designed to increase dead wood for saproxylic fauna in forests without affecting native tree species. In northern Italy, the most widespread exotic tree in alluvial forests is the North American Robinia pseudoacacia. We quantified the difference in species composition and abundance among saproxylic beetles of two European broad‐leaved trees, Populus alba and Quercus robur, and the exotic broad‐leaved tree Robinia pseudoacacia. We collected beetles emerging from 29 fallen trunks with a diameter of between 29 and 31 cm and belonging to the second decomposition stage. We identified 249 individuals from 25 saproxylic beetle species. Species richness and composition did not differ among tree species. Although permutational multivariate analysis of variance highlighted significant differences in species composition, linear mixed effect models showed that differences depend exclusively on spatial distances between logs and not on the host tree species. The Morisita‐Horn index and principal coordinate analysis confirmed this pattern. Thus, we found that saproxylic beetles use all dead trees available in the forest, without distinguishing between exotic or native trees but only occupying the nearest ones. From a forest management point of view, this supports the practice of leaving dead wood of exotic trees at restorations for saproxylic beetles.

Effects of a Major Tree Invader on Urban Woodland Arthropods.

Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity.

Temperature-related effects on the germination capacity of black locust (Robinia pseudoacacia L., Fabaceae) seeds

Germination is a key trait promoting species invasiveness and has become a major goal in invasion ecology. In this study, the effects of different scarification methods and temperature regimes on seed germination performance of the invasive exotic tree Robinia pseudoacacia L. were investigated. Ripe seeds were gathered from six collection sites in Tuscany (central Italy). Mechanical, chemical and thermal scarifications and no pretreatment were applied; seeds were incubated in a range (9–21°C) of constant temperature regimes. The scarification treatments proved highly important for the germination performance of seeds in term of both final response and germination rate in time, with mechanical scarification being the most effective treatment. Temperature significantly affected the germination rate and the mean germination time of the mechanically scarified seeds. The cumulative germination rate significantly decreased with the reduction of the temperature, with the highest value in the 18–21°C regimes (ca 98%), and the lowest in the 9–12°C regimes (ca 60%). The mean germination time slightly decreased with increasing temperature, but was substantially similar between 18°C and 21°C. Our data indicate that the temperature affected the onset of seed germination and that the lowest temperature tested delayed germination. These plastic germination responses, as well as the high germination capacity at lower temperature, may result in the spread of the propagule germination over a large time interval, contributing to the invasiveness of this species.

Seasonality of sprouting in the exotic tree Robinia pseudoacacia L. in Hokkaido, northern Japan

Robinia pseudoacacia L., one of the major invasive tree species in Japan, has been used for coppice wood production worldwide. However, we have little knowledge of the species' sprouting characteristics. Here, we tested seasonality in R. pseudoacacia sprout development. We removed aboveground parts of R. pseudoacacia at different times throughout the year (spring, summer, autumn, and winter) and censused sprout demographics for three consecutive growing seasons thereafter. The most vigorous sprouting was observed among trees cut in winter, while sprouting was lowest among those cut in summer. Sprout abundance in the spring- and autumn-cut treatments was intermediate between that of winter- and summer-cut treatments. Both trunk diameter and season affected stump sprout biomass after three growing seasons, following the same seasonal pattern as above. We found a negative relationship between the herbaceous vegetation cover height and the biomass of root suckers. Both trunk removal in summer and consecutive sprout-clipping treatments contributed to the decline of living stumps. Our results show that R. pseudoacacia trees should be cut during the dormant season to facilitate coppicing and in the summer to facilitate control or removal. Conservation of herbaceous vegetation cover, together with consecutive sprout clipping, will aid the complete removal of this species.

Interactions between seedlings of the invasive tree Ailanthus altissima and the native tree Robinia pseudoacacia under low nutrient conditions

The allelopathic effect of A. altissima and the nitrogen fixing ability of R. pseudoacacia make the interaction between these two species important to community dynamics. A replacement series greenhouse experiment was used to investigate the type of interaction between seedlings of A. altissima and R. pseudoacacia at high and low soil nutrition states. Also, seeds of A. altissima from its native (China) and invasive ranges (USA) were used to compare the effect of the different seed sources on the interaction with R. pseudoacacia. Robinia pseudoacacia was the better competitor. The presence of A. altissima significantly inhibited nodulation of R. pseudoacacia roots. In summary, in low nutrient early succession sites, seedlings of R. pseudoacacia and A. altissima will coexist and R. pseudoacacia will be the better competitor. However, A. altissima can increase its competitive ability by inhibiting nitrogen fixation by R. pseudoacacia. Differences between the competitive ability of the Chinese and US seed lots of A. altissima did not support the rapid evolution theory for invasive species success.

Ecosystem legacy of the introduced N2-fixing tree Robinia pseudoacacia in a coastal forest

Habitat invasibility has been found to increase dramatically following the alteration of ecosystem properties by a nonnative species. Robinia pseudoacacia, black locust, is a nitrogen-fixing, clonal tree species that aggressively invades open habitats and expands outside of plantations worldwide. Robinia pseudoacacia stands in Cape Cod National Seashore were particularly susceptible to a hurricane in 1991 that caused widespread blowdown and a dramatic reduction in Robinia in some stands. We used this change to investigate the lasting ecological effects of this nonnative species on this upland coastal ecosystem. We established replicate clusters of 20 × 20 m field plots within 50 m of each other that contained native pitch pine (Pinus rigida) and oak (Quercus velutina, Q. alba) forest, living Robinia stands, and stands in which Robinia was eliminated or reduced to less than 5% cover by the hurricane. Net nitrification and extractable soil nitrate concentration differed significantly between stand types, in the order Robinia > former Robinia > pine-oak. Nonnative species cover differed significantly between each stand type, in the order Robinia > former Robinia > pine-oak. Invasion of Robinia pseudoacacia increased soil net nitrification and nitrogen availability and precipitated a change in forest species composition that favored nonnative species. The presence of elevated soil nitrogen and nonnative species persisted at least 14 years after the removal of the original invading tree species, suggesting that the invasion of a tree species left a legacy of altered soil biogeochemistry, a higher number of nonnative species, and greater nonnative species cover.

Reproduction of a Robinia pseudoacacia population in a coastal Pinus thunbergii windbreak along the Kujukurihama Coast, Japan

We investigated reproduction of the clonal tree Robinia pseudoacacia in a Pinus thunbergii windbreak. Microsatellite polymorphism analysis revealed that asexual reproduction through horizontal root elongation and ramet formation was the primary mode of reproduction in this population. Germination experiments indicated that the inability of established genets to produce viable seeds inhibited sexual reproduction. The boundaries between genet areas were relatively distinct, indicating that ramets within genets spatially excluded one another. Analyses of the number of annual rings and thickness of excavated horizontal roots provided new insight regarding photosynthate transfer through horizontal roots. The number of annual rings and thickness were highest for horizontal roots near the base of ramets and decreased along portions far from ramets. This result indicates that the new horizontal root is supplied with photosynthate from the mother ramet for a few years only, and that resource translocation between neighboring ramets within the same clone ceases after several years. Hypotheses about horizontal root expansion and cessation were considered to explain the exclusive distribution pattern of the horizontal root between genets.

Hypersensitivity to black locust (Robinia pseudoacacia) pollen: “allergy mirages”

The allergenicity of the ornamental tree Robinia pseudoacacia, or black locust, is unknown. To evaluate the prevalence of sensitization to R. pseudoacacia pollen, its possible allergenic cross-reactivity with other common pollens, and the potential implication of pollen panallergens (profilin, polcalcin, and 1,3-beta-glucanase) as a cause of sensitization to R. pseudoacacia pollen. Skin prick testing with R. pseudoacacia pollen was performed in 149 patients with pollinosis. Nasal challenge with R. pseudoacacia pollen was performed in 10 patients. The prevalence of sensitization to the recombinant forms of profilin (rChe a 2), polcalcin (rChe a 3), and the N-terminal of the 1,3-beta-glucanase (rNtD of Ole e 9) was investigated. Immunoblotting, enzyme-linked immunosorbent assay, and competitive inhibition assays were performed with R. pseudoacacia pollen and recombinant pollen allergens. Sixty-four patients (43%) had positive skin prick test reactions to R. pseudoacacia pollen. Nasal challenge results were positive in 5 sensitized patients and negative in 4 controls and 1 sensitized patient. The allergenic profile of R. pseudoacacia pollen comprises at least the panallergen profilin, a calcium-binding protein, and a 1,3-beta-glucanase. The prevalence of sensitization to rChe a 2, rChe a 3, and rNtD of Ole e 9 was 60%, 33%, and 87%, respectively, among patients sensitized to R. pseudoacacia pollen. Binding of IgE to R. pseudoacacia extract was completely inhibited by Robinia, Chenopodium, Olea, Cupressus, and Lolium extracts. The high prevalence of R. pseudoacacia pollen sensitization in patients with pollinosis is likely to be due to cross-sensitization to panallergens (profilin, polcalcin, and 1,3-beta-glucanase) from other common pollens. This phenomenon may lead to a diagnosis of "allergy mirages."

Effects of increased atmospheric CO2, temperature, and soil N availability on root exudation of dissolved organic carbon by a N-fixing tree (Robinia pseudoacacia L.)

Root exudation has been hypothesized as one possible mechanism that may lead to increased inputs of organic C into the soil under elevated atmospheric CO2, which could lead to greater long-term soil C storage. In this study, we analyzed exudation of dissolved organic C from the roots of seedlings of the N-fixing tree Robinia pseudoacacia L. in a full factorial design with 2 CO2 (35.0 and 70.0 Pa) × 2 temperature (26° and 30 °C during the day) × 2 N fertilizer (0 and 10.0 mM N concentration) levels. We also analyzed the decomposition rates of root exudate to estimate gross rates of exudation. Elevated CO2 did not affect root exudation of organic C. A 4 °C increase in temperature and N fertilization did, however, significantly increase organic C exudation rates. Approximately 60% of the exudate decomposed relatively rapidly, with a turnover rate of less than one day, while the remaining 40% decomposed more slowly. These results suggest that warmer climates, as predicted for the next century, may accelerate root exudation of organic C, which will probably stimulate rapid C cycling and may make a minor contribution to intermediate to more long-term soil C storage. However, as these losses to root exudation did not exceed 1.2% of the net C fixed by Robinia pseudoacacia, root exudation of organic C appears to have little potential to contribute to long-term soil C sequestration.

A test of a potential short cut in the nitrogen cycle: The role of exudation of symbiotically fixed nitrogen from the roots of a N-fixing tree and the effects of increased atmospheric CO2 and temperature

N-fixing trees facilitate the growth of neighboring trees of other species. These neighboring species benefit from the simple presence of the N fixation symbiosis in their surroundings. Because of this phenomenon, it has been hypothesized that a change in atmospheric CO2 concentration may alter the role of N-fixing trees in their environment. It is thought that the role of N-fixing trees in ecosystems of the future may be more important since they may help sustain growth increases due to increased CO2 concentration in nitrogen limited forests. We examined: (1) whether symbiotically fixed N was exuded from roots, (2) whether a doubled atmospheric CO2 concentration would result in increased organic N exudation from roots, and (3) whether increased temperature or N availability affected N exudation from roots. This study analyzed exudation of dissolved organic N from the roots of seedlings of the N-fixing tree Robinia pseudoacacia L. in a full factorial design with 2 CO2 (35.0 and 70.0 Pa) × 2 temperature (26 or 30 °C during the day) × 2 N fertilizer (0 and 10.0 mM N concentration) levels. Trees with no other source of N except N fixation exuded about 1% to 2% of the fixed N through their roots as dissolved organic N. Increased atmospheric CO2 concentrations did not, however, increase N exudation rates on a per gram belowground biomass basis. A 4 °C increase in temperature and N fertilization did, however, significantly increase N exudation rates. These results suggest that exudation of dissolved organic N from roots or nodules of N-fixing trees could be a significant, but minor, pathway of transferring N to neighboring plants in a much more rapid and direct way than cycling through death, decomposition and mineralization of plant residues. And, while exudation rates of dissolved organic N from roots were not significantly affected by atmospheric CO2 concentration, the previously observed ‘CO2 fertilization effect’ on N-fixing trees suggests that N exudation from roots could play a significant but minor role in sustaining increases in forest growth, and thus C storage, in a CO2 enriched atmosphere.

Molecular cloning of two classes of Em-like proteins from the seeds of the leguminous tree Robinia pseudoacacia.

To check for the presence of Em-like proteins in seeds of the leguminous tree Robinia pseudoacacia L. (black locust), a cDNA library constructed from mRNA isolated from developing seeds was screened using radiolabeled cDNA encoding the Em protein from Vigna radiata as a probe. Sequence analysis of the identified cDNA clones revealed two classes of Em proteins in Robinia. The nucleotide sequence data for each class have been submitted to Genbank/EMBL Data library and are available under the accession numbers U40820 and U40821. Northern blot analysis demonstrated that the Robinia Em proteins are translated from mRNAs of approximately 800 nucleotides, which are abundant in the seed but are not expressed in the bark. Southern blot analysis indicated that the Em proteins in Robinia are encoded by at least two genes. The Robinia Em proteins have a high degree of sequence homology with previously characterized Em-like proteins from both monocots and dicots.