Native Plant Species Diversity Research Articles

Fine-resolution land cover mapping over large and mountainous areas for Lāna‘i, Hawaii using posterior probabilities, and expert knowledge

ABSTRACT The task of accurately mapping species-specific vegetation cover in remote and topographically complex regions like those found in Hawaiʻi presents unique challenges. This study leverages a machine learning approach to accurately classify vegetation into fine species-specific classes across the island of Lāna‘i, Hawaii, offering a novel methodology for tackling such challenges. Utilizing high-resolution WordView-2 satellite imagery, a neural network classifier and a custom lidar-based geometric correction, we introduced two new approaches to refine our high-resolution land cover classifications. This included the implementation of prior-based adjustments to class posterior probabilities to enhance land cover classification accuracy. Moreover, we developed mixed hierarchical classification maps that use class posterior probabilities to identify, at the pixel level, the finest land cover class that meets a user-defined confidence threshold. The resulting high-resolution land cover map for Lāna‘i captures the rich diversity and distribution of native and invasive plant species with high overall accuracy, generally exceeding 95%, based on independent ground control data. The capacity to produce wall-to-wall species-level vegetation maps provides a new window into monitoring vegetation dynamics on Lāna‘i and similarly remote and topographically complex regions, and contributes to our broader understanding of ecosystem responses to invasive species, climatic changes, and land management practices such as erosion and sediment control planning. Our approach offers a blueprint for similar efforts in other complex and remote ecosystems.

Impact of Prosopis velutina Wooton on the Composition and Diversity of Native Woody Species in a Semi-Arid Zone along the Molopo River, South Africa

Invasive alien species represent one of the main threats to biodiversity and species extinction. This is the case for the genus Prosopis, among which Prosopis velutina is the most invasive and common tree species along the Molopo River in the North-West Province, impacting native plant communities. However, its impact on the composition and diversity of native woody species remains poorly investigated in the area. Thus, this study aimed to assess the impact of P. velutina on native woody plant composition and diversity across three sites along the Molopo River. At each site, five quadrats of 20 × 20 m2 were randomly established in invaded and adjacent uninvaded stands. A comparative methodological approach was adopted, and the woody plants in invaded and uninvaded stands with similar site conditions were sampled. The results showed that native woody species density differed significantly (p < 0.05) between invaded and uninvaded stands, except for Bray sites, where there was a marginal difference (p = 0.6). The overall native woody species density decreased by 79.7% in the invaded stand. However, non-metric multidimensional scaling (nMDS) and analysis of similarity (ANOSIM) indicated significant differences in native tree composition between invaded and uninvaded stands at all sites. In all three sites, all ecological indices had significantly lower values in invaded stands compared to uninvaded stands. The decrease in all ecological indices in invaded over uninvaded stands indicated that P. velutina invasion reduced the diversity of native woody plant species. Due to the incessant spread of P. velutina, it may become a long-term dominant species with an increasing impact on the native vegetation. Therefore, the findings of this study call for urgent management and appropriate control measures against the ongoing spread of this invader within the riparian zones of the Molopo River in North-West Province.

Artificial developed habitats can sustain plant communities similar to remnant ecosystems in the Tokyo megacity

Artificially developed habitats in urban ecosystems, known as novel ecosystems, have recently been underscored in terms of increasing urban green cover. However, patterns of changes in species diversity and composition in novel ecosystems over time remain poorly understood, making it unclear whether all novel ecosystems contribute to urban biodiversity. Here, we assessed how plant species diversity and composition in developed habitats changed over the years since the development of habitats (years since development) using a space-for-time substitution approach in the megacity, Tokyo, Japan. We established multiple survey transects at each study site to investigate the plant species diversity and composition. Using the ordination regression-based approach, we found that the plant species composition in developed habitats changed over the years since development and became similar to that in remnant habitats after approximately 130 years. We also found that the diversity of native plant species did not change whereas that of exotic species decreased with the years since development. Our results demonstrate the importance of developing new habitats for conserving urban biodiversity, while highlighting that exotic species can easily establish in newly developed habitats. Given that remnant ecosystems in urban areas are degraded by urbanization, the time required for novel ecosystems to become similar to remnant ecosystems is essential for predicting and conserving future urban ecosystems.

Smart strategies for the penetration of 100% renewable energy for the Ecuadorian Amazon region by 2050

This research presents a 100% renewable system configured based on its real potential and use of renewable energies for the Ecuadorian Amazon, considered one of the places with the greatest diversity of native plant species on the planet. The transition processes that are born from the central state seek to take a radical turn in the electricity sector but there is still no defined roadmap, this is where this research will allow it to be an important reference for its long-term transformation. The current system is based on fossil fuels and in this study an energy transition process is planned with the support of the EnergyPLAN tool that puts into practice the concept of intelligent energy, progressively and systematically achieving 100% renewable energy for 2050. Finally, after analyzing the results, it is concluded that the energy mix for 2050 can consider 36.47% hydro, 33.04% solar photovoltaic, 29.73% wind energy and other technologies to a lesser extent with 0.74%. Surpluses can be injected into the interconnection sites with Colombia and Peru, also achieving economic income to preserve and expand the infrastructure of the electricity sector. Decision makers can consider this study as a reference before committing economic resources and carrying out modern energy planning.

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

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

Assessing Ecological Recovery of Reclaimed Well Sites: A Case Study From Alberta, Canada

Empirical evaluations of reclamation success are critical for understanding the speed of ecosystem recovery and improving best practices. In this study, we provide a quantitative evaluation of the effectiveness of past (pre-1995) and current (2010) reclamation criteria in creating functioning forest ecosystems on former industrial sites in boreal Alberta, Canada. We compared ecological indicators of ecosystem recovery (vegetation structure and soil properties) on mineral surface leases (MSLs) certified to the pre-1995 or 2010 reclamation criteria with nearby reference areas recovering from harvest (CUT) or fire (FIRE) disturbances. Six CUT and FIRE sites were chosen to compare six 1995MSLs and five 2010MSLs. Averaging 8 years since reclamation, most of the 2010MSLs were characterized by many of the same vegetation structure and soil properties as the FIRE and CUT sites. The 1995MSLs tended to support more agronomic species, notably grasses and non-native forbs, and fewer shrubs, trees, and native forbs than CUT or FIRE sites. Sites with the greatest coverage of herbaceous species (native and non-native grasses as well as non-native forbs) were the most ecologically impaired sites, based on the extreme deviation from reference site conditions. Based on these results, 2010 reclamation criteria appear to be more effectively promoting ecosystem recovery on reclaimed industrial sites than the pre-1995 criteria. While this case study illustrated the potential benefits of straightforward changes to reclamation criteria in terms of including metrics around soil quality and conservation, woody stem requirements and native plant coverage, there is ultimately always room for improvement. For jurisdictions where the objective of the criteria is to restore a forest ecosystem, including criteria geared toward tree establishment would likely be of value in ensuring the speedy return to a forest canopy state. Adding criteria with measures of native plant species diversity may also be of utility as it is well understood that having plant diversity is also a beneficial metric in creating a more resilient vegetation community.

Localization and Distribution of Two Invasive Alien Species Eichhornia crassipes and Echinocloa pyramidalis in the Pool Malebo Eco-region, Democratic Republic of the Congo

Aim: To study the distribution of two invasive alien plants and associated plants as well as their distribution in the Malebo Pool eco-region.&#x0D; Methodology: The study was carried out by direct observation by circulating on a motorized canoe. Plant samples were randomly harvested (n=6) in August 2020 depends on the sites. Plant species identification was performed on the field, and those species of which the identification was difficult, were brought to the laboratory for proper identification according to APG III.&#x0D; Results: 19 species, including two Pteridophytes and 17 Angiosperms, belonging to 19 families and 12 orders were identified. The site of Molondo was the most diversified with 15 plant species, followed respectively by the sites of Mipongo (13 species), Japon (12 species) and Kingabwa (07 species). The plant species Ludwigia abyssinica A. Rich., Ipomoea aquatica Forsk, Eichhornia crassipes (Mart), Pistia stratiotes L, Echinochloa pyramidalis (Lam) and Salvinia molesta D.S. Mitchell were present in all four prospected sites. E. pyramidalis and E. crassipes constitute a serious threat for the environment and are source of erosion/loss of aquatic biodiversity. Physiologically, these species form a mono-specific carpet and eliminate native or autochthonous species of aquatic flora.&#x0D; Conclusions and Suggestions: The invasion of alien species is a consequence of human activities and a concern, as it affects all sectors of society. These plants can alter, disrupt, and degrade many ecosystem services like the disturbing of habitats and the alteration of the environmental and biological conditions around them. They can also reduce light and diversity of native aquatic plant species. Controlling invasive alien species is thus a challenge for the Congolese society. Political decision-makers are therefore invited to take appropriate measures for managing and protecting the local aquatic flora and valorize the invasive plants as potential medicinal remedy.

Interregional features in the taxonomic composition of the Russian segetal floras

The article contains a comparative analysis of the taxonomical structure of the weedy species composition (segetal flora) in eight regions of Russian Federation: Leningrad, Novgorod, Vologda, Rostov and Sverdlovsk Provinces, Udmurt Republic, Republic of Bashkortostan, and Altai Territory. The segetal flora comprised weeds of cereals, root crops and perennial grasses. The comparison was made separately for the native and alien weeds. The number of native species was higher than that of alien species and varied from 137 to 209 species. The number of alien weeds varied from 99 to 179 species. Vologda Province had the lowest diversity of both native and alien plant species. Udmurt Republic had the greatest native species diversity and Altai Territory had the greatest alien species diversity. The Asteraceae, Poaceae, Brassicaceae, Fabaceae, Lamiaceae, Caryophyllaceae and Scrophulariaceae families dominated in both the native and alien fractions. The authors compared the compositions of species, families and genera of native and alien weeds. Native and alien weedy species showed the greatest similarity in their composition in geographically close regions: European Russia and the Urals. As for geographically remote regions – Altai Territory and Rostov Province – native and alien weedy species compositions were distant. At the same time, the levels of similarity among the native species were lower than among the alien ones. This attests to greater variability in the species composition among native weeds than among alien ones.

Urbanization increases floral specialization of pollinators.

Understanding how urbanization alters functional interactions among pollinators and plants is critically important given increasing anthropogenic land use and declines in pollinator populations. Pollinators often exhibit short‐term specialization and visit plants of the same species during one foraging trip. This facilitates plant receipt of conspecific pollen—pollen on a pollinator that is the same species as the plant on which the pollinator was foraging. Conspecific pollen receipt facilitates plant reproductive success and is thus important to plant and pollinator persistence. We investigated how urbanization affects short‐term specialization of insect pollinators by examining pollen loads on insects’ bodies and identifying the number and species of pollen grains on insects caught in urban habitat fragments and natural areas. We assessed possible drivers of differences between urban and natural areas, including frequency dependence in foraging, species richness and diversity of the plant and pollinator communities, floral abundance, and the presence of invasive plant species. Pollinators were more specialized in urban fragments than in natural areas, despite no differences in the species richness of plant communities across site types. These differences were likely driven by higher specialization of common pollinators, which were more abundant in urban sites. In addition, pollinators preferred to forage on invasive plants at urban sites and native plants at natural sites. Our findings reveal indirect effects of urbanization on pollinator fidelity to individual plant species and have implications for the maintenance of plant species diversity in small habitat fragments. Higher preference of pollinators for invasive plants at urban sites suggests that native species may receive fewer visits by pollinators. Therefore, native plant species diversity may decline in urban sites without continued augmentation of urban flora or removal of invasive species.

Species richness, phylogenetic diversity and phylogenetic structure patterns of exotic and native plants along an elevational gradient in the Himalaya

BackgroundSo far, macroecological studies in the Himalaya have mostly concentrated on spatial variation of overall species richness along the elevational gradient. Very few studies have attempted to document the difference in elevational richness patterns of native and exotic species. In this study, this knowledge gap is addressed by integrating data on phylogeny and elevational distribution of species to identify the variation in species richness, phylogenetic diversity and phylogenetic structure of exotic and native plant species along an elevational gradient in the Himalaya.ResultsSpecies distribution patterns for exotic and native species differed; exotics tended to show maximum species richness at low elevations while natives tended to predominate at mid-elevations. Native species assemblages showed higher phylogenetic diversity than the exotic species assemblages over the entire elevational gradient in the Himalaya. In terms of phylogenetic structure, exotic species assemblages showed majorly phylogenetic clustering while native species assemblages were characterized by phylogenetic overdispersion over the entire gradient.ConclusionsThe findings of this study indicate that areas with high native species richness and phylogenetic diversity are less receptive to exotic species and vice versa in the Himalaya. Species assemblages with high native phylogenetic overdispersion are less receptive to exotic species than the phylogenetically clustered assemblages. Different ecological processes (ecological filtering in case of exotics and resource and niche competition in case of natives) may govern the distribution of exotic and native species along the elevational gradient in the Himalaya.

Impacts of an invasive alien Proteaceae on native plant species richness and vegetation structure

The influence of invasive alien plants on plant community structure and above ground biomass in their novel range is poorly understood, as the magnitude and direction of these effects are often species and ecosystem specific. Here we compared community metrices of native plants and soil properties between study sites invaded by Hakea drupacea, uninvaded sites and cleared sites (sites formerly invaded by H. drupacea). A total of 129 plant species belonging to 75 genera were recorded across all study sites. Invasive Acacia saligna, A. longifolia, A. cyclops (Fabaceae) and Leptospermum laevigatum (Myrtaceae) co-occurred with H. drupacea in the invaded sites. Overall plant species richness, which constituted higher number of native plant species, was recorded in uninvaded sites compared to invaded and cleared sites. Plant species composition was similar between uninvaded and cleared sites, but species composition recorded in uninvaded and cleared sites were significantly different from species composition recorded at invaded sites. Litter depth was significantly higher in invaded sites compared to uninvaded and cleared sites. Hakea drupacea did not affect soil properties in invaded sites. Here we show that H. drupacea probably reduces the diversity of native plant species especially in invaded sites probably through the effect of litter production and canopy cover, pointing to a beneficial effect of removal of H. drupacea. We encourage active restoration of sites invaded by H. drupacea at early stages of invasion before the plants become established and suppress the growth of native species.

UHPLC-(ESI)-HRMS and NMR-Based Metabolomics Approach to Access the Seasonality of Byrsonima intermedia and Serjania marginata From Brazilian Cerrado Flora Diversity.

Seasonality is one of the major environmental factors that exert influence over the synthesis and accumulation of secondary metabolites in medicinal plants. The application of the metabolomics approach for quality control of plant extracts is essentially important because it helps one to establish a standard metabolite profile and to analyze factors that affect the effectiveness of the medicinal plants. The Brazilian Cerrado flora is characterized by a rich diversity of native plant species, and a number of these plant species have been found to have suitable medicinal properties. Some of these plant species include Byrsonima intermedia and Serjania marginata. To better understand the chemical composition of these plant species, we conducted a study using the state-of-the-art techniques including the HPLC system coupled to an Exactive-Orbitrap high resolution mass spectrometer with electrospray ionization interface UHPLC-(ESI)-HRMS and by NMR being performed 2D J-resolved and proton NMR spectroscopy. For the analysis, samples were harvested bimonthly during two consecutive years. UHPLC-(ESI)-HRMS data were preprocessed and the output data uploaded into an in-house Excel macro for peak dereplication. MS and NMR data were concatenated using the data fusion method and submitted to multivariate statistical analysis. The dereplication of LC-HRMS data helped in the annotation of the major compounds present in the extracts of the three plant species investigated allowing the annotation of 68 compounds in the extracts of B. intermedia (cinnamic acids, phenolic acids derived from galloyl quinic and shikimic acid, proanthocyanidins, glycosylated flavonoids, triterpenes and other phenols) and 81 compounds in the extracts of S. marginata (phenolic acids, saponins, proanthocyanidins, glycosylated flavonoids among other compounds). For a better assessment of the great number of responses, the significance of the chemical variables for the differentiation and correlation of the seasons was determined using the variable importance on projection (VIP) technique and through the application of the false discovery rate (FDR) estimation. The statistical data obtained showed that seasonal factors played an important role on the production of metabolites in each plant species. Temperature conditions, drought and solar radiation were found to be the main factors that affected the variability of phenolic compounds in each species.

Nematode communities indicate the negative impact of Reynoutria japonica invasion on soil fauna in ruderal habitats of tatra national park in Slovakia

Reynoutria japonica is a globally successful invasive plant that spreads rapidly after introduction, mainly along riparian or road corridors where dense stands often extend over several hundred square meters. Little is known, however, about the impacts of its spread in protected habitats of upland regions. This study was conducted to characterize the communities of plants and soil nematodes in ruderal forest habitats invaded and uninvaded by R. japonica in Tatra National Park, Slovakia. We hypothesized that invasion would reduce the diversity of native plant species, thereby affecting the nematode communities and their trophic structure. We found that invasion by R. japonica reduced the number and coverage of the native plant species and altered nematode communities and their structures. Total nematode abundance, species number and nematode biomass were significantly lower in invaded than uninvaded plots, but species diversity remained unaffected throughout the study. The overall abundance of all nematode trophic groups well represented the negative impact of R. japonica invasion on soil food webs, supported by low values of all maturity indices, a structural index and the Jaccard index of faunal similarity. A weighted faunal analysis similarly characterized the food webs of invaded plots as poorly developed or highly disturbed, with bacterial decomposition and a low C/N ratio. Our findings thus suggest that dense plots of knotweed simplify the structural complexity of the soil environment by reducing the richness of plant species, which may have contributed to the negative changes in the structures of the nematode communities.

The Flora of a Mesic Forest Remnant in Iowa's Paleozoic Plateau: Malanaphy Springs State Preserve (Winneshiek County, Iowa)

We present the results of a floristic inventory and qualitative descriptions of the forest communities occurring in Malanaphy Springs State Preserve (MSSP), located in the Paleozoic Plateau of northeastern Iowa. Most of the 25.9-ha preserve is a mature mesic to dry-mesic deciduous forest community occurring on a steep slope adjacent to the Upper Iowa River. The preserve also contains a small floodplain forest as well as a small highly disturbed forest on the upland. We documented 422 plant taxa in our surveys, including 52 non-vascular taxa, 14 seedless vascular taxa, 3 gymnosperms, and 353 angiosperms. Eighty-seven percent of the vascular plant taxa are native, and 21% of the species have an Iowa coefficient of conservatism score of 7 or higher. Five species are listed by the Iowa Department of Natural Resources as endangered, threatened, or of special concern in the state. This survey provides critical baseline data needed to document future changes in the plant communities of MSSP. We conclude that this preserve is an important example of high-quality mesic deciduous forest communities in Iowa. We further conclude that the species diversity of the preserve is threatened by the cumulative impacts of habitat loss, high levels of deer herbivory, invasive species, nitrogen deposition, and climate change and that active management and strategic policy decisions will be needed to preserve native plant species diversity.

Effects of the invasive plant Xanthium strumarium on diversity of native plant species: A competitive analysis approach in North and Northeast China.

Xanthium strumarium is native to North America and now has become one of the invasive alien species (IAS) in China. In order to detect the effects of the invader on biodiversity and evaluate its suitable habitats and ecological distribution, we investigated the abundance, relative abundance, diversity indices, and the number of the invasive and native plants in paired invaded and non-invaded quadrats in four locations in North and Northeast China. We also analyzed the effects of monthly mean maximum and minimum temperatures, relative humidity (%), and precipitations (mm). Strong positive significant (P < 0.01) correlation and maximum interspecific competition (41%) were found in Huailai between invaded and non-invaded quadrats. Shannon’s Diversity Index showed that non-invaded plots had significantly (P < 0.05) more diversified species than invaded ones. The significant (P < 0.05) Margalef’s Richness Index was found in Huailai and Zhangjiakou in non-invaded recorded heterogeneous nature of plant communities. Similarly, significant (P < 0.05) species richness found in Huailai and Zhangjiakou in non-invaded quadrats compared to invaded ones. Maximum evenness of Setaria feberi (0.47, 0.37), Seteria viridis (0.43) found in Fushun and Zhangjiakou recorded more stable in a community compared to other localities. Evenness showed positive relationship of Shannon Entropy within different plant species. The higher dissimilarity in plant communities found in Huailai (87.06%) followed by Yangyuan (44.43%), Zhangjiakou (40.13%) and Fushun (29.02%). The significant (P < 0.01) value of global statistics R (0.943/94.3%) showed high species diversity recorded in Huailai followed by Zhangjiakou recorded by non-metric multidimensional scaling and analysis of similarity between invaded and non-invaded plots. At the end it was concluded that the diversity indices reduced significantly (P < 0.05) in invaded quadrats indicated that native plant species become less diverse due to X. strumarium invasion. The degrees of X. strumarium invasion affected on species richness resulted to reduce diversity indices significantly in invaded quadrats.

Role of plant diversity on arthropod communities in a restored tallgrass prairie of the U.S. Midwest

We investigated the effects of enhanced plant species diversity on prairie restoration on arthropod community assembly in a restored tallgrass prairie of the U.S. Midwest. Despite weak correlation with the arthropod taxon, enhanced plant species diversity in the restored prairie (RP) promoted the evenness and diversity of arthropod functional groups and led to a divergence of arthropod assemblage in comparison to the ones in old field (OF) and monospecific stand (reed canary grass [RCG]) of exotic reed canary grass (Phalaris arundinacia). Pollinators were most and least abundant in RP and RCG, respectively, and exhibited a positive correlation to plant species diversity. Herbivore abundance, highest in RP, also increased with plant species diversity. The diversity of arthropod functional groups was likely facilitated by structural complexity of the RP vegetation that resulted from the enhanced plant species diversity, particularly flowering and nectar‐producing forbs. Predator abundance, highest in RCG, decreased with plant species diversity and increased with C3 grass cover. The presence of small‐body sized herbivores seemed to attract predators in the RCG site, which has a monospecific vegetation structure of C3 reed canary grass. Our results demonstrate a positive effect of prairie restoration on the diversity of arthropod functional groups. We recommend increasing the diversity of native plant species and reduction (or eradication if possible) of exotic plants in the OF and RCG sites.

Perencanaan Lanskap Mitigasi Tsunami Berbasis Ekosistem Mangrove di Kota Palu

The coastal areas are vulnerable areas to disaster threats, especially the geological hazards of earthquakes accompanied by tsunamis. Palu City, which is located on the west coast of Sulawesi, experienced a natural disaster of an earthquake, tsunami, and liquefaction on September 28, 2018. Based on the Map of Disaster Prone Index in Central Sulawesi Province, Palu City is a tsunami-prone area that is crossed by the Palu-Koro Fault. Tsunami disaster mitigation efforts in coastal areas can be done by planting mangrove ecosystems as a green barrier. The purpose of this study is to analyze the characteristics of the coastal landscape in Palu City and plan the landscape of tsunami mitigation based on mangrove ecosystems in Palu City. The method used spatial analysis method and descriptive method, as well as the research stage, consists of preparation, data analysis, data synthesis, and landscape planning stage. The basic concept of tsunami mitigation landscape planning is to reduce or eliminate disaster risk in coastal areas based on mangrove ecosystems. The concept of spatial pattern concept consists of high hazard zones, medium hazard zones, and low hazard zones. The concept of vegetation refers to the diversity of mangrove and native plant species as green open spaces and green barriers.

Native and exotic plant species diversity in forest fragments and forestry plantations of a coastal landscape of central Chile

Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1010802 1050745 1095046 1140657 FB 0002-2014

EFFECTS OF THE ABUNDANCE OF PARTHENIUM HYSTEROPHORUS ON THE COMPOSITION AND DIVERSITY OF OTHER HERBACEOUS PLANT SPECIES IN SIMANJIRO RANGELAND, TANZANIA

Parthenium hysterophorus is an annual herbaceous plant native to tropical America; and an invasive plant in Africa causing distressing effects on natural flora. This study investigated the effects of P. hysterophorus on the composition and diversity of native herbaceous plant species in Simanjiro rangeland, Tanzania. Plant species count data were collected from 60 (1m2) quadrats. Using generalized linear models (GLM), the abundance of P. hysterophorus was regressed against the abundance and diversity of the native herbaceous plants. Also, Jaccard’s similarity index was used to compare species composition. Results showed that there were 14 herbaceous plant species belonging to 13 genera and 10 families in the study area. Parthenium hysterophorus was the most dominant species recorded. The abundance of P. hysterophorus has a substantial negative effect on the abundance and diversity of other herbaceous plant species. Moreover, Jaccard’s similarity index showed a slightly significant difference between the infested and non-infested areas. This finding suggests that P. hysterophorus has a substantial potential threat on other herbaceous flora which are sources of food and nutrients to livestock and wild animals in the area. Thus, integrated management strategies are required to control the weed from spreading to other nearby rangelands.

&lt;p&gt;&lt;strong&gt;The endemic and range restricted vascular plants of Croatia: diversity, distribution patterns and their conservation status&lt;/strong&gt;&lt;/p&gt;

The Balkan Peninsula is recognized as an important centre of native and endemic plant species diversity as well as an important wildlife refuge area. However, although Croatia hosts more than half of plant species found on the Balkan Peninsula, the endemic taxa have never been evaluated or used to define conservation priorities. We analyzed the qualitative composition of the endemic and range restricted species, their spatial distribution, centres of endemism, and conservation status (non-IUCN). We generated an updated and annotated checklist of 349 endemic or range-restricted plant taxa (6.9% of the entire native flora), subdivided in 231 species, 103 subspecies and 15 hybrids and belonging to 149 genera and 43 families. Among the 231 species, 69 are considered endemic to Croatia and confined to a small area (&lt; 4,500 km2), while 162 are considered range restricted species, which have larger ranges and/or are shared with neighbouring countries. The genera Centaurea and Hieracium have the highest number of endemic and range restricted taxa. Spatial analyses indicated two notable centres of species richness—the mountainous Dinaric Alps and the SE Adriatic coast, including the islands. Regions with a high richness of range-restricted taxa did not coincide with areas of high richness of endemic species. Taxa exhibited modest bimodality with respect to altitudinal distribution. In addition, the greatest diversity of taxa is concentrated in northwest of Croatia and could be related to differences in mean annual air temperatures and the duration of insolation. As regards their conservation status, 13 of the 349 taxa are endangered, and 62 are near threatened or vulnerable. Despite relatively strong legal protection of endemic and range restricted species, 37 taxa remain unprotected. Changes in conservation practice are therefore proposed.