Distribution Of Plant Species Research Articles

The role of soil communities on the germination of a pioneer tree species in the Atlantic rainforest

Climate change has been modifying precipitation and temperature in many regions of the world, prompting changes in plant communities. It also affects soil microbial communities, indirectly influencing plant species distribution through plant-soil feedbacks. Here we report an experiment designed to test seed germination responses to global change, addressed through the interaction between increased temperature and soil microbial communities in a tree species in the Atlantic rainforest, a global biodiversity hotspot. Our objective was to test plant-soil feedbacks in an early colonizer tree species, Schizolobium parahyba, and their interaction with warming. We assessed the role of increased air temperature and soil microbiota in controlling seed germination as a function of distance to mother tree. Higher germination percentages were recorded with extracts of soil microbial communities from the edge of the canopy than with microbial extracts obtained closer to the trunk. These manipulations evidenced that soil microbiota influenced seed germination, being responsible for Janzen–Connell effects. Warming produced major changes in microbial composition but the effect on germination was unclear. Our results may help understand species distribution and coexistence in secondary patches of Atlantic rainforest under warmer conditions, and may contribute to the design of successful restoration programs.

A phytogeographic assessment of the Sierra Madre Oriental physiographic province, Mexico

Background: Different regionalizations have been proposed for the Sierra Madre Oriental (SMOR), but none of them have analyzed its full floristic diversity.
 Hypothesis: The geographical distribution of the vascular plant species of the SMOR allows the identification of floristic regions with unique species that identify them as biogeographic units.
 Studied species: Vascular plants.
 Study site: Sierra Madre Oriental physiographic province, Mexico.
 Methods: Plant species distribution was analyzed in 1 × 1° latitude and longitude grid cells. Characteristic species (those with half or more of their known geographical distribution in Mexico in the SMOR) were identified, and a classification method was applied to distinguish biogeographic regions.
 Results: 8,472 species were recorded in the Sierra Madre Oriental, 3,433 of them considered characteristics, of which 2,158 are endemic to Mexico and 585 are considered strictly endemic to the province. The portions of the SMOR in the states of Coahuila, Nuevo León, Tamaulipas, and San Luis Potosí have a higher species richness and this richness decreases towards the south of the province. Five floristic districts were identified within the SMOR.
 Conclusions: The phytogeographic analysis carried out and its comparison with other regionalizations shows there is still disagreement in the biogeographic delimitation of the Sierra Madre Oriental and to achieve this goal it is necessary to include neighboring provinces in the analyzes, which will allow to identify their unique species and define their biogeographic limits in a more precise way.

Elevational patterns of plant dispersal ability in Southern Europe

Dispersal ability is a functional trait crucial to understand the distribution and spatial dynamics of plant species. This trait influences the abilities of a species to colonize, or thrive, in a region and thus play a central role on its distribution. We investigated the relationship between plant dispersal ability and elevational distribution (within southern Europe). Algorithms combining different plant dispersal traits, such as seed mass, release height, terminal velocity, growth form and dispersal syndrome, were used to estimate dispersal kernels of 929 vascular plant species along elevational gradient. Finally, we calculated Rao’s functional diversity (FD) by analysis of standardized effect size and community mean (CM) for the dispersal distances. The main results show that species, along the elevational gradient, show different dispersal capacity. The greatest dispersal ability was detected at intermediate elevation, while a reduction in dispersal ability along with a convergence in functional diversity was observed with increasing elevation. These results can be explained by variation in environmental constraints along the elevational gradient. Thus, we conclude that short-distance dispersal is crucial in a stressed environment, while long-distance dispersal ability is advantageous to colonize new habitats where environmental constraints are weak.

Cold-air pools as microrefugia for ecosystem functions in the face of climate change.

Cold-air pooling is a global phenomenon that frequently sustains low temperatures in sheltered, low-lying depressions and valleys and drives other key environmental conditions, such as soil temperature, soil moisture, vapor pressure deficit, frost frequency, and winter dynamics. Local climate patterns in areas prone to cold-air pooling are partly decoupled from regional climates and thus may be buffered from macroscale climate change. There is compelling evidence from studies across the globe that cold-air pooling impacts plant communities and species distributions, making these decoupled microclimate areas potentially important microrefugia for species under climate warming. Despite interest in the potential for cold-air pools to enable species persistence under warming, studies investigating the effects of cold-air pooling on ecosystem processes are scarce. Because local temperatures and vegetation composition are critical drivers of ecosystem processes like carbon cycling and storage, cold-air pooling may also act to preserve ecosystem functions. We review research exploring the ecological impacts of cold-air pooling with a focus on vegetation, and then present a new conceptual framework in which cold-air pooling creates feedbacks between species and ecosystem properties that generate unique hotspots for carbon accrual in some systems relative to areas more vulnerable to regional climate change impacts. Finally, we describe key steps to motivate future research investigating the potential for cold-air pools to serve as microrefugia for ecosystem functions under climate change.

Effects of Water Availability on the Relationships Between Hydraulic and Economic Traits in the Quercus wutaishanica Forests.

Water availability is a key environmental factor affecting plant species distribution, and the relationships between hydraulic and economic traits are important for understanding the species’ distribution patterns. However, in the same community type but within different soil water availabilities, the relationships in congeneric species remain ambiguous. In northwest China, Quercus wutaishanica forests in the Qinling Mountains (QM, humid region) and Loess Plateau (LP, drought region) have different species composition owing to contrasting soil water availability, but with common species occurring in two regions. We analyzed eight hydraulic traits [stomatal density (SD), vein density (VD), wood specific gravity (WSGbranch), lower leaf area: sapwood area (Al: As), stomatal length (SL), turgor loss point (ΨTlp), maximum vessel diameter (Vdmax) and height (Height)] and five economic traits [leaf dry matter content (LDMC), leaf tissue density (TD), leaf dry mass per area (LMA), Leaf thickness (LT) and maximum net photosynthetic rate (Pmax)] of congeneric species (including common species and endemic species) in Q. wutaishanica forests of QM and LP. We explored whether the congeneric species have different economic and hydraulic traits across regions. And whether the relationship between hydraulic and economic traits was determined by soil water availability, and whether it was related to species distribution and congeneric endemic species composition of the same community. We found that LP species tended to have higher SD, VD, WSGbranch, Al: As, SL, ΨTlp and Vdmax than QM species. There was a significant trade-off between hydraulic efficiency and safety across congeneric species. Also, the relationships between hydraulic and economic traits were closer in LP than in QM. These results suggested that relationships between hydraulic and economic traits, hydraulic efficiency and safety played the role in constraining species distribution across regions. Interestingly, some relationships between traits changed (from significant correlation to non-correlation) in common species across two regions (from LP to QM), but not in endemic species. The change of these seven pairs of relationships might be a reason for common species’ wide occurrence in the two Q. wutaishanica forests with different soil water availability. In drought or humid conditions, congeneric species developed different types of adaptation mechanisms. The study helps to understand the environmental adaptive strategies of plant species, and the results improve our understanding of the role of both hydraulic and economic traits during community assembly.

Transfer learning from citizen science photographs enables plant species identification in UAV imagery

Accurate information on the spatial distribution of plant species and communities is in high demand for various fields of application, such as nature conservation, forestry, and agriculture. A series of studies has shown that Convolutional Neural Networks (CNNs) accurately predict plant species and communities in high-resolution remote sensing data, in particular with data at the centimeter scale acquired with Unoccupied Aerial Vehicles (UAV). However, such tasks often require ample training data, which is commonly generated in the field via geocoded in-situ observations or labeling remote sensing data through visual interpretation. Both approaches are laborious and can present a critical bottleneck for CNN applications. An alternative source of training data is given by using knowledge on the appearance of plants in the form of plant photographs from citizen science projects such as the iNaturalist database. Such crowd-sourced plant photographs typically exhibit very different perspectives and great heterogeneity in various aspects, yet the sheer volume of data could reveal great potential for application to bird’s eye views from remote sensing platforms. Here, we explore the potential of transfer learning from such a crowd-sourced data treasure to the remote sensing context. Therefore, we investigate firstly, if we can use crowd-sourced plant photographs for CNN training and subsequent mapping of plant species in high-resolution remote sensing imagery. Secondly, we test if the predictive performance can be increased by a priori selecting photographs that share a more similar perspective to the remote sensing data. We used two case studies to test our proposed approach with multiple RGB orthoimages acquired from UAV with the target plant species Fallopia japonica and Portulacaria afra respectively. Our results demonstrate that CNN models trained with heterogeneous, crowd-sourced plant photographs can indeed predict the target species in UAV orthoimages with surprising accuracy. Filtering the crowd-sourced photographs used for training by acquisition properties increased the predictive performance. This study demonstrates that citizen science data can effectively anticipate a common bottleneck for vegetation assessments and provides an example on how we can effectively harness the ever-increasing availability of crowd-sourced and big data for remote sensing applications.

Wildlife of the Tamaulipan Brush in the Dispersion of Chapote (Diospyros Texana Scheele) Seeds

In nature, all seeds need external agents (biotic or abiotic) to ensure their movement. Dispersion mechanisms turn out to be an essential factor in the natural distribution of plant species and in the mobilization and exchange of genetic material within and outside populations. The objective of this research was to analyze the interaction that the native wildlife in the Tamaulipas scrub has with the fruit of one of the species of the “Chapote” plant species (Diospyros texana) and its contribution to the dispersal of seeds. The research was carried out at the Experimental Campus of the Faculty of Forest Sciences of the UANL, Mexico, located in the municipality of Linares, NL, Mexico, during the month of July and August 2019. The method used was by means of photo-trapping to monitor the fauna that interacts with the species in question. It was possible to conclude that the average distance of distribution of excreta with seeds of Diospyrus texana was three meters. Some members of the wild fauna of mammals present in the vegetation of the Tamulipec scrub were white-tailed rabbit (Sylvilagus floridanus), gray squirrel (Sciurus aureogaster), raccoon (Procyon lotor), armadillo (Dasypus novemcinctus) and coyote (Canis latrans); they feed on the fruits of Diospyrus texana and thus act as dispersers of its seeds. Key words: dispersal, facilitation, wildlife, seeds, Diospyros

Plant beta-diversity across biomes captured by imaging spectroscopy

Monitoring the rapid and extensive changes in plant species distributions occurring worldwide requires large-scale, continuous and repeated biodiversity assessments. Imaging spectrometers are at the core of novel spaceborne sensor fleets designed for this task, but the degree to which they can capture plant species composition and diversity across ecosystems has yet to be determined. Here we use imaging spectroscopy and vegetation data collected by the National Ecological Observatory Network (NEON) to show that at the landscape level, spectral beta-diversity—calculated directly from spectral images—captures changes in plant species composition across all major biomes in the United States ranging from arctic tundra to tropical forests. At the local level, however, the relationship between spectral alpha- and plant alpha-diversity was positive only at sites with high canopy density and large plant-to-pixel size. Our study demonstrates that changes in plant species composition and diversity can be effectively and reliably assessed with imaging spectroscopy across terrestrial ecosystems at the beta-diversity scale—the spatial scale of spaceborne missions—paving the way for close-to-real-time biodiversity monitoring at the planetary level.

AIRBORNE LASER SCANNING CHANGE DETECTION FOR QUANTIFYING GEOMORPHOLOGICAL PROCESSES IN HIGH MOUNTAIN REGIONS

Abstract. Disturbance by geomorphic processes is a key factor for current and potential plant species distributions in high mountain regions. We implemented and tested an approach for the detection, quantification, and geomorphological classification of 3D topographic change using airborne laser scanning (ALS) data. This approach is applied to two point cloud epochs (from 2006 and 2017) to identify and analyse changes related to five different process categories in a study area in the European Alps: Fluvial Processes, Rock Glacier Movement & Landslides, Channel Erosion & Debris Flow, Rockfall Release & Deposition and Vegetation & Anthropogenic Change. The results are assessed through comparison with a manually produced geomorphological map. The analysis covering the eleven-year time period provides detailed information on the magnitudes and spatial distribution of change per identified geomorphological process. The study shows that the workflow is capable of providing the fundamental basis for mapping vegetation disturbance by geomorphic activity in a high alpine site.

Tree species with conservative foliar nutrient status and strong phosphorus homeostasis are regionally abundant in subtropical forests

Abstract Foliar nitrogen (N) or phosphorus (P) status and their stoichiometric homeostasis are integral parts of the plant nutrient economy that determines the success of plant species in environments where N or P limits plant growth. Despite growing evidence for higher predictability of stoichiometric homeostasis of N (HN) than that of P (HP) on plant species abundance in temperate grasslands, no previous studies explicitly examined how foliar N and P status modulate the relationships between stoichiometric homeostasis and species distribution (regional species abundance) of woody plants, especially in P‐limited (sub)tropical ecosystems. We hypothesized that species with a conservative foliar nutrient status but a higher HP (but not HN) would be regional abundant in P‐limited forest. We measured foliar N (LNC) and P (LPC) contents of 54 woody species, community composition and soil N and P contents across 94 forest plots in Chinese subtropical forests. Then we evaluated the species' levels of N and P stoichiometric homeostasis and their regional abundance to test our hypotheses. HN and HP significantly increased with decreasing LNC and LPC. Foliar nutrient status positively correlated with the minimum values of both soil N and P contents, but only negatively associated with the maximum value of soil P content, indicating that conservative species can occupy a wider range of soil P‐ than N‐based nutrient niche. Meanwhile, species abundance negatively correlated with LNC and LPC, and positively correlated with HN and HP. However, the structure equation model analysis showed that species abundance increased with decline of LNC but not yet with increased HN. In contrast, species abundance enhanced with increased HP and decreased LPC via HP, rather than directly with a decline of LPC. Synthesis. This study provides empirical evidence that species with conservative foliar nutrient status are more stable in terms of N and P stoichiometric homeostasis, and foliar N and P economy modulate species abundance distribution in different ways. Our results suggest that maintaining strong stoichiometric homeostasis of leaf P, while maintaining conservative economy of N, is a key physiochemical mechanism for shaping species abundance distribution in P‐limited forests.

HyDiaD: A hybrid species distribution model combining dispersal, multi-habitat suitability, and population dynamics for diadromous species under climate change scenarios

Diadromous species are particularly vulnerable to climate change because they utilize both marine and freshwater habitat to complete their life cycles. Dispersal plays an important role in restraining the distribution of plant and animal species, and is a key mechanism to allow diadromous species to adapt to changes in habitat suitability, but it is often not included in species distribution models that explore population trends under climate scenarios. The objective of this study was to develop a model to estimate potential shifts in diadromous populations in the Atlantic area of Europe under two climate change scenarios and multiple global climate models. To address the question of range-shift responses, a hybrid approach for diadromous species distribution (HyDiaD) was developed that incorporated two components: i) statistical static models of habitat suitability describing the influence of environmental factors on species occurrence, and ii) biological processes relevant for the distribution of the species, such as population demography and dispersal dynamics. Hybrid models were developed using a novel approach that incorporated both population and between-catchment dispersal dynamics specific to each species. Occupancy data for diadromous species in a subset of Atlantic Area catchments were first validated by regional experts, and boosted regression trees were applied to estimate habitat suitability within each catchment based on historical physical and climatic environmental predictors from the continental and marine domains. Habitat suitability was then used in a population dynamics model that incorporated between-catchment dispersal and local population growth. Results for different-sized catchments were compared using time series of spawner density and saturation rate, which estimated how much of the available habitat was being utilized. Many of the species-specific values used in HyDiaD were estimated through a survey of diadromous species experts, and group consensus was reached by calculating weighted averages. The HyDiaD model was applied to two shad species (Alosa alosa and A. fallax) to explore population trends projected annually from 1951 to 2100. Projected trends indicated that under XXIst century climate scenarios, habitat suitability is expected to increase for A. fallax, but decrease for A. alosa. Projected trends also indicated an increase in the rate of annual variability for A. alosa, particularly in the southern part of its range. Future studies can utilize the HyDiaD model to explore distribution trends for other diadromous species under climate change scenarios.

More time to fly: with a warming climate the Western honey bee (Apis mellifera, Linnaeus) now has more temperature-eligible flight hours than 40 years ago

There have been official NOAA and EPA reports of measurable changes in temperature across the United States over the last several decades with average temperatures increasing in most areas and decreasing in a few others. In order to fly, honey bees need optimal temperatures ranging from 13 °C (55 °F) to 38 °C (100 °F), sunlight, low wind, and no rain. This study looks at changes in temperature-eligible flight times of honey bees across the US and Canada. Four decades of weather data from 60 locations in the US and Canada for the period 1980 through 2019 were analyzed. We discovered that honey bee flight hours are increasing almost everywhere, but most dramatically in the northern regions of Canada and Alaska, and also in a few locations in the US south of the border with Canada. Warming temperatures (ignoring all other factors), may lead to more flight time for honey bees; may affect plant bloom times and species distributions; and may change the exposure of honey bee colonies to pests, parasites, and pathogens. Therefore, beekeepers must be prepared to modify management practices to accommodate possible plant–pollinator mismatches and timings for seasonal and pest management. This study highlights that a warming climate will increase temperature-eligible flight hours for honey bees. Further research is needed to consider how other climate change factors, in combination with temperature, will affect actual honey bee flight opportunities and behavior, as well as, overall colony management.

A lesson from Bass Strait on connectivity conservation

AbstractIsolation effects on the distributions of plant species in fragmented forests appear to be weak over tens to hundreds of years and strong over geological eras. The 250 km wide, 6.5 millennia old Bass Strait, and other millennium‐scale disjunctions in the range of Eucalyptus regnans forests, were used to determine the effects of intermediate periods of isolation on plant species occurrence and composition. Three of six floristic communities were found on both sides of Bass Strait. The residuals from multiple regression models using climatic variables on the latitude vector were not explained by latitude, indicating negligible isolation effects from Bass Strait. However, there was a lesser compositional effect of disjunctions within land masses than between land masses, suggesting some effect of the larger barrier. No species that commonly occurred with E. regnans and were largely confined to wet forest exhibited absences from any region where the climate and soils were within their range. If areas isolated from each other for millennia can maintain their vascular plant biota, the expenditure of conservation funds on creating corridors to connect large areas separated by anthropogenic landscape modification might require more justification than it is currently afforded.

Lack of coordination between stomatal and vein traits provides functional benefits to the dioecious tropical tree Myrsine coriacea.

Climate change will affect the distribution of many tropical plant species. However, the understanding of how dioecious tropical species cope with different environmental conditions is still limited. To address this issue, we investigated how secondary trait attributes in populations of the dioecious tropical tree Myrsine coriacea change along an altitudinal gradient. Eighty individual plants (40 male and 40 female) were selected among seven natural populations. Leaf variation in morphological and stomatal traits, and carbon and nitrogen isotopic compositions were analyzed. Female plants had greater isotopic leaf carbon composition (δ13 C) and nitrogen content than male plants, increasing their carboxylation capacity. Plants of both sexes had smaller stomata, greater water-use efficiency (greater δ13 C), and greater nitrogen isotopic composition (δ15 N) at higher altitudes. They also showed lower δ15 N and had greater carbon: nitrogen ratios at lower altitudes. There was a lack of coordination between stomatal and vein traits, which was compensated for by variation in specific leaf areas. This mechanism was essential for increasing plant performance under the limiting conditions found by the species at higher altitudes.

Plant species diversity, abundance and conservation status of the Ankasa Resource Reserve, Ghana

Knowledge of the floristic composition, structure and conservation status of tropical forests is essential for their sustainable management and conservation, although this remains poorly documented in some tropical countries. Here, we investigated the plant species diversity, distribution and conservation status of the Ankasa Resource Reserve, Ghana, to inform management and conservation efforts. A total of 150 plots (20 m × 20 m each) were demarcated across six recognizable sites, namely; Lophira Tree (LT), Bucket Trail (BT), Big Tree Area (BGA), Bamboo Cathedral (BC), Elubo Camp (EC) and “Dadwen” (DW) for enumeration of trees. Smaller nested plots were used for saplings (5 m × 5 m) and seedlings (1 m × 1 m). Patterns in composition and structure were assessed using various diversity and abundance metrics, whereas the global conservation status of species were determined from the IUCN Red List. In all, 7521 individuals, belonging to 239 species and 65 families, were recorded in the study. The LT was the most diverse of the six habitats (richness = 113, Shannon = 4.32) whereas the BC (62, 3.63) was the least. Hill numbers and rarefaction curves confirmed these variations. Non-metric multidimensional scaling analysis revealed three distinct compositional units or community types in the reserve. Across all sites, Dacryodes klaineana, Picrilima nitida, Drypetes gilgiana and Gluema ivorensis dominated the tree layer, with IVI (%) of 6.71, 5.69, 5.00, 3.88, respectively. Leguminosae, Apocynaceae and Euphorbiaceae were the most dominant families. Of the 239 species identified, 15.9% are classified as near threatened to threatened with extinction, 62.3% of least concern, and 20% not been evaluated. The DW and EC have the highest conservation values while BGA and BC have the least. The results confirm the high floristic richness and conservation status of the Ankasa reserve, and suggest the need for priority conservation actions to maintain its biodiversity.

Quantification and Consumption Pattern of Fuel Wood in Mornaula Reserve Forest in Kumaun, Indian Himalaya: Implication for Sustainability and Conservation

Present study provides information on biomass utilization, fuel wood species diversity, their regeneration status, and impact of fuel wood harvesting in Mornaula Reserve Forest (MRF) in Kumaun, India. A total of 34 plant species (32 trees and 2 shrubs) were collected by the inhabitants for fuel, belonging to 22 families, dominated by Rosaceae (04 species) followed by Pinaceae and Lauraceae (02 each). Distribution of plant species ranges from1500-2200 in a wide range of habitats, forests being the most preferred one. High preference and Resource Use Index of Quercus leucotrichophora, Quercus floribunda , and Rhododendron arboreum, Pinus roxburghii, Myrica esculenta, Symplocos chinensis, and Cedrus deodara as fuel indicated high pressure on these species. The continuous exploitation of these species from the MRF may lead to rapid deletion of their population. Therefore, adequate conservation measures have to be taken to maintain the current status of the habitats, species and communities for the effective management of the MRF. Awareness among the villagers needs to be created for the resource utilization techniques, so that sustainable utilization of the species could be done by the villagers. Further, the degraded forests may be re-established through plantations of the seedlings of the preferred fuel wood species with the participation of local inhabitants.

Mapping three-dimensional morphological characteristics of tidal salt-marsh channels using UAV structure-from-motion photogrammetry

Tidal channels (TCs) are geomorphological features of coastal and tidal landscapes. They provide a pathway for the exchange of material and energy between marshes and adjacent water bodies and thereby control the hydrodynamic, morphological, and ecological processes on marsh platforms. Due to difficulties in terms of accessibility, limitations on the duration of exposure during low-water stages, and variations in morphology over time, rapid and accurate mapping of such intertidal morphological features at a high frequency is extremely challenging. Here, we present an efficient method integrated unmanned aerial vehicles (UAVs) structure-from-motion (SfM) photogrammetry, and spatial morphological fitting and delineation for accurately quantifying channel three-dimensional (3D) morphological features in terms width, depth, width-to-depth ratio, and cross-sectional area. We also relate these measured proxies to salt marsh species distributions. A two-step thresholding approach combining elevation and slope is developed in order to determinate TC boundaries from salt marsh and tidal flat area, and a Gaussian fit is used to estimate water-bearing channel depth and cross-sectional area. Salt marsh species are identified from fine-resolution multispectral satellite data and a field training dataset using a Random Forest classifier. Our results indicate that (1) UAV-based SfM photogrammetry can achieve centimeter-level accuracy in mapping the topography of TCs, with a root mean square error (RMSE) of 5.7 cm — mainly from the strong reflection of light from smooth TC water surfaces and the presence of water-bearing layers; (2) the morphological features of TCs, ranging from tidal flats to salt marsh areas, demonstrate a similar tendency, which increases at first and then decreases. The maximum depth and cross-sectional area of TCs is in sparse salt-marsh area, up to 4 m and 150 m2, respectively; and (3) TC morphology has a major impact on the distribution of salt marsh plants and such effects vary across different plant species. These results greatly contribute deep understanding of feedbacks between TCs and salt marsh plant species distribution and have significant implications for developing ecological and morphological salt marsh restoration guidelines.

DIVERSITY AND DISTRIBUTION PATTERN OF ALIEN PLANT SPECIES ALONG THE ALTITUDINAL GRADIENT IN DISTRICT PAURI, UTTARAKHAND, INDIA

Human activities are involved in direct destruction of habitats. Next to man alien invasive plants are major threats to natural ecosystem. The present study attempts to understand baseline information which can measure future effects of climate change and anthropogenic changes on vegetation in mountain areas. The observed pattern of associations between species distribution and elevation zones is likely to help in understanding the possible effects of climate change and its impact in alien plant species distributions shifting towards higher altitudes. Maximum alien species distribution is found at 1600 to 2000 m (amsl) in the study site. A total of 82 plant species under 72 genera, belonging to 39 families are identified as alien plant species based on extensive field observations, herbarium and literature consultations. Distribution of invasive species based on growth form shows that the maximum number of exotic species contribution in the study area are herbs (56%), followed by shrubs(20%), and trees (24%). Among these Tropical American native species contribute 26%, South American native species contribute 21%, and African, European species each realm respectively contribute 9%, 8%. In the study area 67% alien species are naturalized and 33% species are casual. There is an increasing concern among foresters, ecologists, botanists, conservationists, and policy makers about the threat of uncontrolled introduction of alien aggressive, invasive plant species.

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.

Soil chemical variables improve models of understorey plant species distributions

AbstractAimSpecies distribution models (SDMs) assume that all ecologically relevant predictor variables are included. This assumption is frequently violated in SDMs of plant species, as soil variables are rarely included. Here, we used in‐situ, soil geochemical variables along with more commonly used topo‐climatic and remotely sensed variables to create SDMs of understorey plant species. We evaluated whether the potential importance of soil variables is greater than generally described in SDM literature, which predictors are most important, and whether a standard subset of predictors can be used to effectively model all species.LocationNorthern Appalachian Mountains.TaxonVascular, forest understorey plants.MethodsWe fit models for the presence of 41 forest understorey plant species across 158 plots using soil, topographic and spectral predictors.ResultsModels containing all three predictor types performed best. Soil and topographic variables had comparable importance; spectral variables were of lesser importance. The best predictor variable was B horizon carbon to nitrogen ratio (B C:N), followed by topographic position index, elevation and B horizon exchangeable calcium (B Ca). A standard subset of variables did not effectively model all species.Main conclusionsOur results and those of other SDMs that include in‐situ soil geochemical data suggest that soil variables are increasingly important with more detailed descriptions of soils. Soil fertility data, such as B C:N and B Ca, are particularly important in acidic, forest soils where pH is a poor indicator of fertility. Commonly used topo‐climatic variables provide meaningful predictions but are limited by their use of indirect predictor variables, inhibiting transferability and interpretability. The poor performance of a standard subset of variables highlights the uniqueness of each species' niche and the need to have a variety of predictor variables.