Rare Plant Species Research Articles

Eco-evolutionary causes and consequences of rarity in plants: a meta-analysis.

Species differ dramatically in their prevalence in the natural world, with many species characterized as rare due to restricted geographic distribution, low local abundance and/or habitat specialization. We investigated the ecoevolutionary causes and consequences of rarity with phylogenetically controlled metaanalyses of population genetic diversity, fitness and functional traits in rare and common congeneric plant species. Our syntheses included 252 rare species and 267 common congeners reported in 153 peer-reviewed articles published from 1978 to 2020 and one manuscript in press. Rare species have reduced population genetic diversity, depressed fitness and smaller reproductive structures than common congeners. Rare species also could suffer from inbreeding depression and reduced fertilization efficiency. By limiting their capacity to adapt and migrate, these characteristics could influence contemporary patterns of rarity and increase the susceptibility of rare species to rapid environmental change. We recommend that future studies present more nuanced data on the extent of rarity in focal species, expose rare and common species to ecologically relevant treatments, including reciprocal transplants, and conduct quantitative genetic and population genomic analyses across a greater array of systems. This research could elucidate the processes that contribute to rarity and generate robust predictions of extinction risks under global change.

Deer Exclusion Regenerates Native Plant Functional Responses, but Not Species Richness in an Eastern Serpentine Savannah

Plants are particularly vulnerable to physical disturbance in low productivity areas, due to the high energetic cost of replacing lost tissue. In the eastern United States, serpentine savannahs are fragmented ecosystems with high concentrations of rare endemic plant species, low concentrations of soil nutrients, and severe deer overpopulation. This study assessed the recovery of flowering plants in a serpentine savannah when deer were excluded. Plant count, flower count, vegetative area, and plant height of 10 serpentine plant species were compared inside and outside of deer exclusion structures throughout an entire growing season. Throughout the growing season and across the plant community, deer exclusion consistently increased values for all plant response traits measured. Species that responded most strongly to deer exclusion included Arabis lyrata (Brassicaceae, the wide ranging lyre-leaf rockcress) and the serpentine near-endemic Symphyotrichum depauperatum (a serpentine aster known only in the eastern US). The slender knotweed, Polygonum tenue performed worse in excluded areas, which may indicate exclusion by more competitive species, or, alternatively, local scarcity. Overall, species richness did not increase in excluded plots, which may indicate that years of deer overbrowsing have depleted the local seed banks. While longer term studies might reveal different results, this study showed significant differences in vegetation response traits between excluded and unexcluded areas in just one year. We recommend that further restoration efforts should include reintroductions of locally extirpated species, in combination with deer exclusion to allow rare serpentine plant communities and their seedbanks to recover from intense overbrowsing pressure.

Development of novel polymorphic microsatellite markers for Picea brachytyla.

Picea brachytyla is a unique tree species in China. Due to being extensively exploited in the past, it is listed as Vulnerable in the IUCN Red List. It is mainly distributed across the Hengduan and Daba-Qinglin mountains and has been found in other areas including Sichuan Province and Qinghai Province, China. Microsatellites, or simple sequence repeats (SSRs), are widely used in correlational studies of genetic protection. Few markers have been developed for P. brachytyla because of the small number of trees and scholarly resources available for study. The genomic DNA of P. brachytyla was sequenced using the DNBSEQ platform, and unigenes were obtained after assembly and deredundancy. Of the 100 primer pairs screened, we isolated 10 useful microsatellite loci from P. brachytyla genes. The observed and expected heterozygosity values ranged from 0.173 (P24) to 0.788 (P79; mean 0.469) and 0.199 (P87) to 0.911 (P79; mean 0.700), respectively. Polymorphism-information content (PIC) ranged from 0.190 (P84) to 0.904 (P79; mean 0.666). Only P84 and P72 were in a Hardy-Weinberg equilibrium (P > 0.05) in the different P. brachytyla populations. All the levels of linkage disequilibrium (LD) were high for the 10 SSR loci indicating that there were no autocorrelations among the 10 SSR loci. The novel polymorphic microsatellite markers showed high polymorphism for P. brachytyla. These polymorphic microsatellites can provide a basis for future conservation and genetic research on this rare plant species.

Методические аспекты работ по реинтродукции редких растений и восстановлению нарушенных фитоценозов

The threat of extinction of wild flora plants and their habitats is rapidly increasing around the world. Despite the worldwide mobilization of resources for the conservation of biodiversity, it continues to be lost on an unprecedented scale at all levels. In this regard, there is a serious reassessment of methods of biodiversity conservation. At the same time, increased attention is paid to the restoration of destroyed phytocenoses (ecological restoration) and reintroduction in an attempt to minimize the consequences of habitat destruction and species extinction. Information is provided on the state of work on the reintroduction of rare plant species in the botanical gardens of Russia. The basic methodological principles of work on reintroduction are formulated. The experience of restoring disturbed natural phytocenoses is considered separately. Keywords: REINTRODUCTION OF RARE PLANT SPECIES. METHODS OF WORK. RESTORATION OF DISTURBED NATURAL PHYTOCENOSES

Addition of fungal inoculum increases germination of orchid seeds in restored grasslands

Grasslands restored on arable land often retain high residual nutrients, modified soil biota, and lower plant species diversity. Establishment of rare plant species with complex multitrophic interactions, typical of undisturbed nutrient-poor environments, may be hindered by the absence of interacting organisms. We hypothesised that the addition of a mycorrhizal symbiont improves the seed germination of orchids that crucially depend on fungi. We focused on grasslands restored on arable land 1–15 years ago featuring residual mineral nutrients and low organic matter contents compared to semi-natural grasslands and on four orchid species differing in the level of mycorrhizal specificity: high – Anacamptis pyramidalis and Orchis mascula – and low – Platanthera bifolia and Gymnadenia conopsea. Five fungal isolates obtained from non-green underground mycorrhizal orchid seedlings (protocorms) or adults' roots were tested for orchid-fungus compatibility under conditions in vitro. Orchid seeds inserted in retrievable seed packets were subsequently co-introduced with selected fungal isolates grown either on agar or sterilized hay into the soil of nine restored grasslands and incubated for twelve months. The identity of mycorrhizal fungi in retrieved protocorms was verified by molecular methods. The isolates that supported protocorm establishment in vitro enabled also protocorm formation in situ, but success rates differed among orchid species. While mycorrhizal specialists produced most protocorms after inoculation, the mycorrhizal generalists took advantage of naturally occurring fungi and produced some protocorms both in inoculated and uninoculated treatments. We showed that the addition of mycorrhizal fungi enhanced protocorm formation regardless of the modified soil environment, especially in mycorrhizal specialist orchids. This method may help to restore populations of native orchid species in their former distribution ranges, including farming-altered habitats.

The effect of plant growth regulators on the in vitro regeneration capacity in some horticultural crops and rare endangered plant species

ISHS IX International Scientific and Practical Conference on Biotechnology as an Instrument for Plant Biodiversity Conservation (physiological, biochemical, embryological, genetic and legal aspects) The effect of plant growth regulators on the in vitro regeneration capacity in some horticultural crops and rare endangered plant species

On the structure of populations of rare steppe plant species under anthropogenic pressure (Middle and Lower Volga region)

In the article the population structure of 20 rare representatives of flora of the Middle and Lower Volga region (European part of Russia) is considered. Methods of population-ontogenetic direction were used during the work. Data on cenopopulations were obtained by medium- and long-term monitoring. The structure of cenopopulations of 20 species was studied: Ajuga chia Schreb., Artemisia salsoloides Willd., Artemisia santonica L., Artemisia taurica Willd., Astragalus cornutus Pall., Astragalus temirensis M. Pop., Astragalus zingeri Korsh., Atraphaxis frutescens (L.) C. Koch., Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult., Clausia aprica (Steph.) Korn.-Tr., Halocnemum strobilaceum (Pall.) M. Bieb., Hedysarum gmelinii Ledeb., Hedysarum grandiflorum Pall., Hedysarum razoumovianum Fisch. et Helm, Medicago cancellata Bieb., Oxytropis floribunda (Pall.) DC., Oxytropis hippolyti Boriss., Polygala sibirica L., Silene cretacea Fisch. ex Spring., Rindera tetraspis Pall. It was established that population characteristics of many rare representatives of the steppe flora of the Volga region are similar and depend on the type and duration of ontogenesis, life strategy and intensity of anthropogenic pressure on the places of growth.

Rare and endemic plant species of Mountain Crimea flora: a morphogenic response to conservation in the gene bank in vitro

Biotechnological approaches have been actively used in recent years to preserve rare and endemic plant species under slow growth conditions. This is reached by lowering the temperature and light intensity, increasing the osmotic concentration, introducing retardants into the culture medium. For conservation, we used microshoot segments of Lamium glaberrimum (K. Koch) Taliev (Lamiaceae), Crepis purpurea L. (Asteraceae), Scrophularia exilis Popl. (Scrophulariaceae), Silene jailensis N. I. Rubtzov (Caryophyllaceae) cultured under standard in vitro conditions for 8‒10 months. The explants were placed on ¼ MS culture medium supplemented with plant growth inhibitors: 0.2 g/L 2-chloroethyl-trimethyl-ammonium chloride (CCC) and 60 g/L sucrose. Conservation conditions were: the temperature 4–6 °C, light intensity 1.25–3.75 µM m-2 s-1, photoperiod 16 hours. Screening of the morphometric parameters indicated high viability and a decrease in growth kinetics after 12 and 24 months of deposition in the gene bank in vitro. Along with the microshoot slow growth, the formation of adventitious shoots, leaves, and roots was observed.

Floristic findings in the Republic of Tuva and in the south of the Krasnoyarsk Territory (Upper Yenisei basin)

In the course of field research, analysis of previously published works and review of materials stored in well-known collection funds of Siberia (NS, KRAS, SSHZ), information on the distribution of rare adventitious and native plant species in the Upper Yenisei basin was clarified. For the first time, Arctium lappa, Armoracia sisymbrioides, Bupleurum sibiricum, Calystegia sepium, Lolium perenne, Pastinaca sativa, and Polygonum subaphyllum were noted for the flora of the Republic of Tuva. Stipa glareosa was collected for the first time on the territory of the Krasnoyarsk Territory. Viola tricolor was turned out to be new for the flora of the Sayano-Shushensky Reserve. For 10 rare species, new locations were noted and range boundaries were specified: Acer tataricum, Armoracia rusticana, Avena fatua, Carduus nutans, Clematis aethusifolia, Convolvulus arvensis, Polygonum rurivagum, Sedum acre, Setaria pumila, and Viola tricolor.

Inventory of Rare Fruit in Sibohe Forest of Singkawang City, West Kalimantan

The location close to urban areas and the rapid rate of decline in area can threaten the diversity of rare fruits in the Sibohe Forest. A re-survey in the Sibohe Forest, Singkawang, West Kalimantan was conducted to confirm reports of the existence of 15 rare fruit plant species collected in 2017-2018 by previous researchers. The inventory process started from collection of specimens carried out during June-July 2021, herbarium making, identification and descriptive data analysis. Based on the similarity of regional names, 13 out of 15 species were confirmed according to the previous reports, while 2 species were not found due to the possibility of out of fruiting season. However, 4 of the 13 confirmed species were identified with different scientific names. Additional survey to the people in Pontianak City aged 17-34 years revealed some different names for the same type of fruit among these four species. Four new plant species were also collected and described in this study including amok (Alpinia sp., Zingiberaceae), nubik (Artocarpus sp., Moraceae), tehengan (Artocarpus sp., Moraceae), and smallest arok (Ficus sp., Moraceae). Potentials and challenges in the inventory of rare fruit plants in the Sibohe Forest should be studied regularly as well as efforts to increase public knowledge and interest, especially for the younger generation. Moreover, recommendation should be made to support conservation activities based on the actual data collected in the field regularly.

Responses of Antioxidants Enzymes to Oxidative Stress in the Floral Species Drimia Maritime

In natural habitats, plants that encounter adverse growth conditions are preserved in natural reserves where rare or endangered species, such the rare plant species Drimia maritima are protected. However, abiotic stress, generated by air pollution near Bentael natural reserve - Lebanon, where Drimia maritima is widespread, is suspected to induce alteration in the biochemical status of the plant.

DiZF-C3H1, a zinc finger transcription factor from the dove tree (Davidia involucrata Baill.), plays a negative role in seed development and plant growth in Arabidopsis and tobacco

Low seed fertility seriously limits the survival and adaption of rare plant species. Here, we identified a seed-specific gene, DiZF-C3H1, from the dove tree and verified its function. Overexpression of DiZF-C3H1 caused retarded root development, delayed anthesis, abnormal floral organs, and deformed siliques in transgenic Arabidopsis lines. No offspring were obtained in transgenic Arabidopsis lines due to serious seed abortion. Therefore, we performed further verification in tobacco. Similarly, overexpression of DiZF-C3H1 retarded root development and reduced berry size and seed yield in transgenic tobacco lines. Moreover, although transgenic tobacco offspring were obtained, the viability of transgenic seeds was reduced and their germination was delayed. In addition, faded flowers were observed in transgenic tobacco lines. Taken together, DiZF-C3H1 was verified to play a negative role in root growth, floral organ development, and especially seed development in Arabidopsis and tobacco. This appears to be a deleterious gene for these model plants with high seed fertility. However, this function might be of special significance for Davidia, whose seed dormancy period is extremely long; DiZF-C3H1 might play a critical role in the distinctive reproduction strategy adopted by this rare and endangered species.

The Matthew effect: Common species become more common and rare ones become more rare in response to artificial light at night.

Artificial light at night (ALAN) has been and still is rapidly spreading and has become an important component of global change. Although numerous studies have tested its potential biological and ecological impacts on animals, very few studies have tested whether it affects alien and native plants differently. Furthermore, common plant species, and particularly common alien species, are often found to benefit more from additional resources than rare native and rare alien species. Whether this is also the case with regard to increasing light due to ALAN is still unknown. Here, we tested how ALAN affected the performance of common and rare alien and native plant species in Germany directly, and indirectly via flying insects. We grew five common alien, six rare alien, five common native, and four rare native plant species under four combinations of two ALAN (no ALAN vs. ALAN) and two insect-exclusion (no exclusion vs. exclusion) treatments, and compared their biomass production. We found that common plant species, irrespective of their origin, produced significantly more biomass than rare species and that this was particularly true under ALAN. Furthermore, alien species tended to show a slightly stronger positive response to ALAN than native species did (p=.079). Our study shows that common plant species benefited more from ALAN than rare ones. This might lead to competitive exclusion of rare species, which could have cascading impacts on other trophic levels and thus have important community-wide consequences when ALAN becomes more widespread. In addition, the slightly more positive response of alien species indicates that ALAN might increase the risk of alien plant invasions.

Trait divergence between endemic plants of Aegean islands and their widespread congeners

Evolutionary processes on islands, and the attributes of rare plant species restricted to islands have received increasing attention in the last decade, but most of the evidence comes from oceanic archipelagos while continental islands have been much less studied. We test if narrow endemic species of Aegean islands (E Mediterranean region) have evolved particular trait values and ecological attributes. In 64 pairs of congeneric species i.e., an island endemic and a congeneric widespread species, we compared morphological traits (both vegetative and reproductive), and altitudinal range using a phylogenetically constrained multilevel model. Island endemics had larger propagules, larger petals, shorter stems, shorter flowering duration, and they occupied a narrower altitudinal range. The results are interpreted in terms of lower competitive ability and lower dispersal capacity in Aegean endemics. Larger corolla could be accounted for by competition for pollinators in insect-rich ecosystems. Field observations are needed to test if island endemics and their widespread congeners occupy distinct niches when in sympatry on the same island.

EVALUATION OF THE ELEMENTAL COMPOSITION OF ANTHEMIS TROTZKIANA CLAUS IN THE REGIONS OF WESTERN KAZAKHSTAN

The article presents the results of evaluation studies on the elemental composition of Anthemis trotzkiana Claus plants growing in the Aktobe region in Western Kazakhstan. All selected samples from three populations of a rare plant species for chemical composition were examined by atomic absorption spectroscopy. Evaluation studies of the elemental composition of the vegetative organs of A. trotzkiana have shown that extracts obtained from leaves, roots, and stems of plants can be a promising source of macro- and microelements for pharmacopoeial purposes. Endemism of the species A. trotzkiana, distributed locally in the regions of Western Kazakhstan, requires measures for the rational use of this species.

Agri-environment schemes are associated with greater terrestrial invertebrate abundance and richness in upland grasslands

Agri-environment schemes are a key mechanism by which agricultural sustainability is encouraged by subsidising farmers to adopt environmentally friendly management (e.g. reduction of inputs) to maintain and enhance the delivery of biodiversity-associated ecosystem services. Studies testing the efficacy of agri-environment schemes have yielded varying results, and few have focused on upland (marginal or Less Favoured Area) grassland (> 150 m above sea level) where productivity is poor. This study used a factorial field experiment to examine patterns in plant communities and terrestrial invertebrates between agri-environment scheme and conventionally managed semi-improved and improved upland grasslands, using 90 spatially paired fields. Total plant species richness and rare plant species richness (those with < 10% occurrence) were unaffected by agri-environment scheme management, but were significantly higher on semi-improved than improved grasslands. Total and rare invertebrate abundance and family-level richness were unrelated to grassland type (semi-improved or improved). Total and rare invertebrate abundances were 4% and 218% higher, and total and rare invertebrate family-level richness were 17% and 14% higher in agri-environment scheme than conventionally managed fields, respectively. Here, we show that agri-environment scheme management of marginal or Less Favoured Area upland grassland was associated with higher multi-taxa invertebrate abundance and richness associated with swards indicative of wetter conditions with lower dominance of perennial ryegrass (Lolium perenne) and greater coverage of other native grass species compared to conventional management. This suggests that agri-environment schemes may maintain, enhance or offset declines in terrestrial invertebrates and their associated ecosystem service delivery by maintaining more diverse swards, and suggests that they make a positive contribution to biodiversity conservation.

Status surveys of Helonias bullata (swamp pink) in New Jersey: Long-term declines from deer browse and hydrological change1

Systematic field surveys were conducted in 2010–13 for the threatened, globally rare plant species, Helonias bullata L. (swamp pink: Liliaceae) in New Jersey, which contains 60% of known populations. A total of 90 sites were visited, including 56% of extant populations, focusing on the highest quality, largest, and most geographically representative populations in the state in order to comprehensively assess the species' status. A complete census and threat assessment was conducted for each population, using standardized methods adopted during previous surveys in 1997–2001, and population trends were determined by comparing results between data sets. The results found declines in 83% of Helonias populations in the past 10 yr, including severe declines (> 67%) in 53% of populations, and another 26% experiencing declines of 20% or more. Analyses of past and present data sets found the primary cause of declines appeared to be herbivory by white-tailed deer (Odocoileus virginianus), which had not been previously regarded as a significant threat to the species, followed by hydrological changes caused by human development and/or water consumption. Browse damage to Helonias was directly observed in 84% of populations, with an average of 40% of Helonias clusters exhibiting recent damage at each site. Concern for observer bias was also explicitly addressed in the methods and analyses providing further confidence in the results. Implications for the conservation and recovery of Helonias are discussed, as well as the benefits and limitations of the standardized methods used for long-term studies of this and other rare plant species in the future.

The current state of the introduction coenopopulation of Gymnospermium odessanum on the botanical-geographical plot “Steppes of Ukraine” at the M. M. Gryshko National Botanical Garden of the NAS of Ukraine

Gymnospermium odessanum is a rare relict endemic plant species. The research was carried out during G. odessanum flowering in 2019–2021 at the botanical-geographical plot “Steppes of Ukraine” of the M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine (NBG). Ecological and coenotic conditions of introduction at the NBG differ from natural habitats of the species and are not optimal for its vegetation. However, this species demonstrated ecological-coenotic plasticity and, over the decades, has formed a stable homeostatic introduction coenopopulation here. As of 2021, the area of introduction coenopopulation of G. odessanum at the NBG was 2,075 m2. It comprises 412 individuals of this species (including 40 seedlings, 241 juvenile, 45 immature, 40 virginal, 45 generative, and 1 sub-senile plants). Coenopopulation fragments with a high density of G. odessanum individuals are rare here, so the average density is low – only 0.2 individuals per 1 m2. In 2021, in the spectrum of age states, the total percentage of pregenerative individuals was very high and reached 88.8 %; the share of generative individuals was 10.9 %.In general, the age structure of the introduction coenopopulation of G. odessanum is characterized by long-term (2010–2021) stability. The spatial distribution of individuals in the introduction coenopopulation is of two kinds – random and in groups. This is due to combined myrmecochoric and barochoric propagation. Also due to myrmecochory, this coenopopulation tends to spread the area. Compared to natural coenopopulations, the introduction coenopopulation of G. odessanum at the NBG is characterized by a larger area, a much significant number, and, at the same time, a low average density of individuals. However, like in most of natural populations, its age spectrum is left-sided.The conducted research testifies the successful formation of the introduction coenopopulation of G. odessanum in the meadow-steppe cultural phytocoenosis of the NBG. This introduction coenopopulation is an example of a successful multi-year scientific experiment and effective ex situ protection and preservation of G. odessanum on the northern border of the Right Bank Forest-Steppe of Ukraine, far beyond the natural range of this endemic plant species.

Modeling Habitat Suitability for Stewartia ovata Across the Southeastern United States

Mountain stewartia (Stewartia ovata) is a rare shrub or small tree endemic to the higher elevation regions of Georgia, Tennessee, and Alabama with isolated populations occurring in Kentucky, North Carolina, South Carolina, Virginia, and Mississippi. The species is often misidentified or overlooked by land managers and conservationists. As a result, mountain stewartia's habitat and distribution descriptions are limited for restoration and conservation use. Modeling a species' habitat suitability has become a critical first step in conserving rare and imperiled plant species. These models allow conservationists to locate previously undocumented populations and prioritize populations and habitats for conservation. This study presents a habitat suitability model for mountain stewartia across its known natural range based on maximum entropy (Maxent) modeling with nine environmental predictor variables and 60 occurrences from herbarium records (n=22), research-grade iNaturalist observations (n=25), and other author identified locations (n=3). The resulting habitat suitability map was classified into bins for spatial analysis. A total of 376,030 ha (0.44% of the study area) was designated within the top tier bin with the highest suitable habitat. Further, 133,344 ha (0.16% of the study area) of the top bin was found on publicly owned lands, indicating approximately 35.56% of the highest habitat suitability occurs within public lands. The presented model could allow plant conservationists to prioritize areas for conservation, reintroduction, and may lead to the discovery of previously undocumented populations.

Spatiotemporal Variations in Seed Set and Pollen Limitation in Populations of the Rare Generalist Species Polemonium caeruleum in Poland.

A vast majority of angiosperms are pollinated by animals, and a decline in the number and diversity of insects often affects plant reproduction through pollen limitation. This phenomenon may be particularly severe in rare plant species, whose populations are shrinking. Here, we examined the variability in factors shaping reproductive success and pollen limitation in red-listed Polemonium caeruleum L. During a 5-year study in several populations of P. caeruleum (7–15, depending on year), we assessed the degree of pollen limitation based on differences in seed set between open-pollinated (control) and hand-pollinated flowers. We analysed the effects of flower visitors, population size, and meteorological data on plant reproductive success and pollen limitation. Our study showed that pollen limitation rarely affected P. caeruleum populations, and was present mainly in small populations. Pollen limitation index was negatively affected by the size of population, visitation frequency of all insects, and when considering the visitation frequency of individual groups, also by honeybee visits. Seed production in control treatment was positively influenced by the population size, average monthly precipitation in June and visits of hoverflies, while visits of honeybees, average monthly temperature in September, and average monthly precipitation in August influenced seed production negatively. As generalist plant P. caeruleum can be pollinated by diverse insect groups, however, in small populations their main visitors, the honeybees and bumblebees, may be less attracted, eventually leading to the disappearance of these populations. In pollination of P. caeruleum managed honeybees may play a dual role: while they are the most frequent and efficient flower visitors, their presence decreases seed set in open-pollinated flowers, which is most probably related to efficient pollen collection by these insects.