Herbaceous Plant Species Richness Research Articles

Influence of an Organic Fertilizer on Agronomic Characteristics and Herbaceous Plant Diversity in a Greek Ecosystem: The Case of Cretan Dittany (Origanum dictamnus L.)

In recent years, there has been a growing tendency towards using organic fertilizers instead of chemical ones. This study aimed to evaluate the influence of the organic fertilizer, Prima Humica, on agronomic characteristics and herbaceous plant diversity on Origanum dictamnus (Dittany) cultivation. A field experiment was carried out in Kalo Xorio (Lasithi, Crete) and included three different nitrogen organic fertilization schemes: 0 g/plant (T0—unfertilized), 300 g/plot (T1), and 600 g/plot (T2). Plant height, fresh and dry weight, Leaf Area Index (LAI), and plant diversity during the growing season were measured. The results showed that when the T2 treatment was compared with the unfertilized and the T1 fertilizer, the increase in plant height ranged between 9.18% and 40.61%. Moreover, the total fresh and dry weight were positively affected by the T2 treatment. The total fresh and dry weight varied from 111.6 to 239.8 g per plant and from 36.7 to 77.6 g per plant, respectively. Furthermore, LAI was ameliorated using the T2 fertilizer scheme. Concerning plant diversity, a key finding in this study is that the O. dictamnus ecosystem favors herbaceous plant species richness and Shannon’s diversity index. In total, 18 plant species in the O. dictamnus ecosystem were recorded in the study area. The most frequently occurring plants were Anthemis arvensis L. and Piptatherum miliaceum (L.) Coss. Finally, the highest Shannon’s diversity index of herbaceous plants was detected using the T2 fertilizer scheme.

Dynamics of Agronomic Characteristics and Plant Diversity in Lemon Verbena (Aloysia citrodora Paláu) Cultivation in Greece

Nowadays, there is an increasing negative environmental effect of using chemical fertilizer. For this reason, the use of biofertilizers is promoted in the agriculture sector. The purpose of this investigation was to carry out an evaluation of the effects of biological fertilizer (biofertilizers are organic materials that can be used to improve soil properties) use on the growth and agronomic characteristics of Aloysia citrodora. To achieve this aim, a two-year randomized complete blocks field experiment was carried out in central Greece. The experiment included four biological fertilizer levels (0, 50, 100 and 150 N kg ha−1) with three replications. Plant height, dry stem, dry leaves, dry total yield and leaf area index (LAI) were measured during the two growing years. The results showed that in the first and second studied years, the maximum plant height and total dry yield were observed in the BF150 treatment. Moreover, LAI was ameliorated by applying the BF100 and BF150 treatments in both studied years. A key finding in this study is that the A. citrodora ecosystem favors herbaceous plant species richness. Also, soil factors (soil organic matter, P and K) promote positive herbaceous plant diversity within the A. citrodora ecosystem. Finally, A. citrodora could be a promising medicinal plant, cultivated under Mediterranean climatic conditions.

Gallery forest species and water quality of the Okpara River in northern Benin

This study aims to understandf the relationships between water quality, vegetation and human activity in the forest gallery of the Okpara River in northern Benin. Within this framework, floristic surveys and measurements of physicochemical parameters were carried out on 48 sites along the watercourse, located in 8 villages bordering the river. Sociodemographic surveys were also carried out among neighboring populations. The densities of Khaya senegalensis, Mitragyna inermis, Vitellaria paradoxa, Cola laurifolia and Isoberlinia doka of the wooded stratum and the recoveries of Andropogon gayanus, Cassia mimosoïdes, Panicum maximum, Andropogon tectorum, Hyptechis suaveolens and Aptechis suaveolens increased from upstream to downstream. The water can be considered as water of average quality according to the parameters measured. It emerged that the density of Berlinia grandiflora, Isoberlinia doka and Combretum glutinosum on one hand, and the recovery of Andropogon gayanus, Cassia mimosoïdes, Detarium microcarpa and Gynandropsis gynandra on other hand were particularly linked to the physicochemical parameters of water. There was a relative strong relationship between the two groups of parameters with the first canonical coefficient estimated at 0.75. The species richness of shrubs and herbaceous plants, water temperature, Biochemical Oxygen Demand for 5 days and, to a lesser extent, dissolved oxygen contributed to the relationship between the two groups of variables. The importance of human activities from upstream to downstream was also a factor that had a detrimental effect on water quality and on the composition of riparian flora. This information is important for a good sustainable management of these resources.

The alien Chinese windmill palm (Trachycarpus fortunei) impacts forest vegetation and regeneration on the southern slope of the European Alps

AbstractQuestionsDoes the non‐native evergreen Chinese windmill palm (Trachycarpus fortunei) affect native plant community and forest regeneration in deciduous forests? Are effects modulated by soil moisture? What are the implications for forest management and nature conservation?LocationBroadleaved deciduous low‐elevation forests on the southern slope of the Alps across the Swiss–Italian border region.MethodsWe compared the native herbaceous and woody plant composition, species richness, Shannon diversity and abundance at ten deciduous forest sites on two moisture conditions (six mesic–moist sites and four mesic–dry sites). Each site consisted of three plots measuring 400 m2 along a gradient of T. fortunei presence, ranging from “dominant”, to “present but not dominant” to “absent”.ResultsIn mesic–moist forests with high densities of T. fortunei, species richness and Shannon diversity of native plants and recruiting woody species in the herb and shrub layers were significantly reduced compared to similar sites where T. fortunei is absent or not dominant. However, in mesic–dry forests these variables did not differ between palm‐invaded and uninvaded plots. The abundance of recruiting woody individuals did not differ between plots invaded by palms and uninvaded control plots in either forest type.ConclusionsWe expect detrimental consequences for plant diversity in mesic–moist alluvial forests with high T. fortunei densities and few detrimental consequences in the more widespread non‐alluvial forests. We recommend multifaceted management, including targeted eradication in alluvial forests identified as hotspots of native plant diversity, accompanied by hands‐off management of T. fortunei in non‐alluvial forests, recognizing the ongoing and inevitable “laurophyllisation”; a biome shift toward mixed‐evergreen forest that may increase ecosystem climate resilience under ongoing climatic warming.

Relationships between plant species richness and grazing intensity in a semiarid ecosystem.

Plant species richness is an important property of ecosystems that is altered by grazing. In a semiarid environment, we tested the hypotheses that (1) small-scale herbaceous plant species richness declines linearly with increasing grazing intensity by large ungulates, (2) precipitation and percent sand interact with grazing intensity, and (3) response of herbaceous plant species richness to increasing intensity of ungulate grazing varies with patch productivity. During January-March 2012, we randomly allocated 50, 1.5-m × 1.5-m grazing exclosures within each of six 2500 ha study sites across South Texas, USA. We counted the number of herbaceous plant species and harvested vegetation in 0.25-m2 plots within exclosures (ungrazed control plots) and in the grazed area outside the exclosures (grazed treatment plots) during October-November 2012-2019. We estimated percent use (grazing intensity) based on the difference in herbaceous plant standing crop between control plots and treatment plots. We selected the negative binomial regression model that best explained the relationship between grazing intensity and herbaceous plant species richness using the Schwarz-Bayesian information criterion. After accounting for the positive effect of precipitation and percent sand on herbaceous plant species richness, species richness/0.25 m2 increased slightly from 0% to 30% grazing intensity and then declined with increasing grazing intensity. Linear and quadratic responses of herbaceous plant species richness to increasing grazing intensity were greater for the least productive patches (<15.7 g/0.25 m2) than for productive patches (≥15.7 g/0.25 m2). Our results followed the pattern predicted by the intermediate disturbance hypothesis model for the effect of grazing intensity on small-scale herbaceous plant species richness.

Monitoring Reclamation of Plant Biodiversity and Soil Parameters in an Area of Bauxite Mine Spoils (A Case Study of Greece)

In order to assess plant biodiversity in bauxite mine spoils, a fully randomized experiment was carried out with five treatments to find the ones that would best restore the soil and plant biodiversity in the spring seasons of 2020 and 2021. In the studied area, 68 plant species belonging to 54 genera with high ecological value that comprise the flora and represent 19 families were identified. Concerning the herbaceous plant species richness in several treatments, the highest value was calculated in the treatment of sludge (52 plant species), followed by the treatment of soil in the area (39), whereas the lowest plant species richness was recorded in the treatment of fertilization (27), the incorporation of soil with soils (26), and control (27), so our findings indicate that the area where sludge was applied showed the highest nutrient enrichment as well as the highest plant biodiversity, plant cover, and biomass. Apart from sludge, the mineral soil around the area was also composed of some materials that provided good results with regard to plant parameters. The main problems with the properties of the mine spoil material were the low organic matter content and the low clay percentage. The use of sludge, probably in combination with the soil around the area, might alleviate these problems. The plant parameters (Shannon diversity index, plant cover, and biomass) correlated positively and significantly with most of the macronutrients and micronutrients in soils.

Seasonal variation of herbaceous plant diversity along the urban - rural landscape in Aligarh, Uttar Pradesh, India

The present study aimed to understand the variation in herbaceous plant species diversity in urban (UR) and agricultural (AG) ecosystems of Aligarh. Data on herbaceous plant species richness (no. of species), diversity (Shannon-Wiener’s 'H) and spices dominance (1-D) were collected by laying 270 plots of 0.5*0.5 m at each stratum. We recorded a total of 81 plant species belonging to 75 genera and 29 families. Among them, 62.5 % of species were found in the AG sites and 37.5% in the UR sites. Herbaceous plant richness, and spices dominance were higher in AG in comparison to UR. Conversely, species evenness lower lower in AG compared to UR. At both the strata, species richness was the highest during the monsoon season. The mean Shannon diversity (AG = 1.25±0.03, UR = 0.78±0.03) and dominance (AG = 0.64±0.01, UR = 0.48±0.01) were the highest during the monsoon season, whereas evenness (AG = 0.87 0.01, UR = 0.93 0.007) had maximum value during the summer season. The study concluded that human stresses and disturbance have a greater impact on herbaceous plant diversity in urban areas (UR). These conclusions may have consequences for the planning of green areas in urban landscape and the conservation of plant diversity. However, more research into the processes related to urbanization and plant diversity is required.

Do Woody Plants Facilitate Herbaceous Plants in Dryland New Zealand?

Aims: Woody plants are postulated to facilitate understory herbaceous plants in arid and semi-arid environments worldwide, the so-called ‘nurse plant’ effect, but this mechanism. has been little studied in the drylands of New Zealand. Indigenous dryland plants postulated to have grown under woody shrubs in New Zealand before European settlement may benefit from their recovery, or even their replacement by exotic substitutes. The aim of this study was to investigate woody pant facilitation of understory herbaceous plants in dryland New Zealand.&#x0D; Study Design: In this study I investigated the effects of canopies of four shrub species – Kunzea serotina, Discaria toumatou, Rosa rubiginosa and Coprosma propinqua – on herbaceous plant species richness, in the presence and absence of rabbit grazing (for K. serotina).&#x0D; Place and Duration of Study: The study was conducted in the drylands of Central Otago, New Zealand, from August 2007 to January 2009.&#x0D; Results: Herbaceous plant species richness was lower under canopies of K. serotina, possibly because the dense canopy shaded the understorey plants. It was higher under C. propinqua, D. toumatou and R. rubiginosa canopies than in their adjacent open grasslands, but for all three species this effect was seen only in winter. Woody plant canopy protection of understorey herbaceous plants against winter frost may explain the effects. Grazing significantly decreased herbaceous plant species richness. Since D. toumatou, R. rubiginosa and C. propinqua showed facilitative effects on herbaceous plant species richness they are possible agents for the restoration of dryland vegetation.&#x0D; Conclusion: I conclude that control of grazing and the protection of these three woody species could be a good management strategy for the maintenance of a predominantly indigenous dryland mixed herbaceous and woody vegetation in Central Otago.

Mycorrhizal type of woody plants influences understory species richness in British broadleaved woodlands.

Summary Mature temperate woodlands are commonly dominated by ectomycorrhizal trees, whereas understory plants predominantly form arbuscular mycorrhizal associations. Due to differences in plant–fungus compatibility between canopy and ground layer vegetation the ‘mycorrhizal mediation hypothesis’ predicts that herbaceous plant establishment may be limited by a lack of suitable mycorrhizal fungal inoculum.We examined plant species data for 103 woodlands across Great Britain recorded in 1971 and in 2000 to test whether herbaceous plant species richness was related to the proportion of arbuscular mycorrhizal woody plants. We compared the effect of mycorrhizal type with other important drivers of woodland plant species richness.We found a positive effect of the relative abundance of arbuscular mycorrhizal woody plants on herbaceous plant species richness. The size of the observed effect was smaller than that of pH. Moreover, the effect persisted over time, despite many woodlands undergoing marked successional change and increased understorey shading.This work supports the mycorrhizal mediation hypothesis in British woodlands and suggests that increased abundance of arbuscular mycorrhizal woody plants is associated with greater understory plant species richness.

Impacts of Climatic Factors on Vegetation Species Diversity, Herbaceous Biomass in Borana, Southern Ethiopia

The study was conducted in three districts of Borana Zone, with the objective to determining the impacts of climatic factors on vegetation species diversity, herbaceous biomass yield of Borana rangelands under commonial grazing rangeland types during end of growing season. The most types rangeland of communial properties are traditional enclosure and continuous grazing rangeland from in where our different data were collected. Within both rangeland types of each districts 20 m x 20 m plots that placed at 200 m distances intervals with three replication was used to collect woody vegetation. The data of herbaceous plant community was collected from seventeen quadrants (1 m x1 m) that layout in the main plot. The collected data was analyzed by linear regression to determine the impact of climate factors. The herbaceous species richness, diversity and biomass study sites had highly significantly difference (P &lt; 0.001) and positive linear with mean annual precipitation. There is significantly difference (P &lt; 0.05) and negative linear in woody species richness and diversity. Both herbaceous and woody plant species richness and diversity of study areas had a negative linear with mean annual temperature. Climate factors specieally rianfall have a great impact on rangeland ecosystems of study areas. Therefore, rangeland user should be considering climatic factors to improve productivity of rangeland. Keywords: Rangeland types, Species diversity and richness, herbaceous biomass and rainfall DOI: 10.7176/JEES/12-5-01 Publication date: May 31 st 2022

Effects of stand structure and ungulates on understory vegetation in managed and unmanaged forests.

Conventional conservation policies in Europe notably rely on the passive restoration of natural forest dynamics by setting aside forest areas to preserve forest biodiversity. However, since forest reserves cover only a small proportion of the territory, conservation policies also require complementary conservation efforts in managed forests in order to achieve the biodiversity targets set up in the Convention on Biological Diversity. Conservation measures also raise the question of large herbivore management in and around set-asides, particularly regarding their impact on understory vegetation. Although many studies have separately analyzed the effects of forest management, management abandonment, and ungulate pressure on forest biodiversity, their joint effects have rarely been studied in a correlative framework. We studied 212 plots located in 15 strict forest reserves paired with adjacent managed forests in European France. We applied structural equation models to test the effects of management abandonment, stand structure, and ungulate pressure on the abundance, species richness, and diversity of herbaceous vascular plants and terricolous bryophytes. We showed that stand structure indices and plot-level browsing pressure had direct and opposite effects on herbaceous vascular plant species diversity; these effects were linked with the light tolerance of the different species groups. Increasing canopy cover had an overall negative effect on herbaceous vascular plant abundance and species diversity. The effect was two to three times greater in magnitude than the positive effects of browsing pressure on herbaceous plants diversity. On the other hand, a high stand density index had a positive effect on the species richness and diversity of bryophytes, while browsing had no effect. Forest management abandonment had few direct effects on understory plant communities, and mainly indirectly affected herbaceous vascular plant and bryophyte abundance and species richness and diversity through changes in vertical stand structure. Our results show that conservation biologists should rely on foresters and hunters to lead the preservation of understory vegetation communities in managed forests since, respectively, they manipulate stand structure and regulate ungulate pressure. Their management actions should be adapted to the taxa at stake, since bryophytes and vascular plants respond differently to stand and ungulate factors.

Plant biodiversity declines with increasing coffee yield in Ethiopia's coffee agroforests

Abstract Tropical agroforestry systems provide farmers with resources for their livelihoods, but are also well‐recognized as refuges for biodiversity. However, the relationship between yield and biodiversity might be negative in these systems, reflecting a potential trade‐off between managing for increased yield or biodiversity. The potential for synergies will depend partly on the shape of the biodiversity–yield relationship, where a concave relationship suggests a faster decline in biodiversity with increasing yields than a linear or convex shape. We studied the relationship between biodiversity (plant species richness and composition) and coffee yield along a gradient of management in south‐western Ethiopia, coffee's native range. We inventoried species richness and community composition of woody plants, herbaceous plants and bryophytes at 60 sites. We also measured coffee management‐related variables and assessed coffee yield for 3 consecutive years at each site. Species richness of woody plants had a concave relationship with coffee yield, that is, tree richness declined fast initially before levelling out at higher yields, whereas there was no relationship between coffee yield and species richness of herbaceous plants or bryophytes. Species composition of woody plants, herbaceous plants and bryophytes all had a concave relationship with coffee yield. From a methodological perspective, we found that multi‐year data on yield were necessary to reliably assess the relationship between biodiversity and yield, and that the number of coffee shrubs or coffee dominance were poor proxies for yield when trying to capture the biodiversity–yield relationship. Synthesis and applications. The concave relationship between biodiversity components (species richness and composition) and yield suggests that there is a strong conflict between the goals of increasing production and conserving biodiversity. However, it is important to recognize that this pattern is largely driven by the very low‐yielding sites in natural forests. Here, even minor intensification of coffee management seems to rapidly erode biodiversity. Along the rest of the productivity gradient, there was generally no negative relationship between yield and biodiversity, implying opportunities for developing strategies for increasing yields without biodiversity loss.

Disturbance Impacts of Logging on Ground Herbaceous Plant Species Richness, Diversity, and Composition of Lowland Rainforest of Papua New Guinea

The impact of logging activities on species richness, diversity, and composition of the ground herbaceous layer of the lowland forest of Papua New Guinea was analyzed. Data from the first multipurpose National Forest Inventory were collected in 52 plots from logged and unlogged low altitude forest on plains and fans (P) and forest on uplands (H) in Madang, West New Britain and Central Provinces. The abundance of 10,609 ground herbaceous plants classified in 174 species from 103 genera and 35 families. Based on importance values, Arecaceae was the dominating family in both logged and unlogged P forest type, while Urticaceae and Arecaceae were dominating respectively in logged and unlogged H forest type. At species level, Donax canniformis and Elatostema beccarii are dominating the P type, and Elatostema novoguineensis and Selaginella durvillei the H type. Analysis of species richness, diversity, and composition showed significant differences between the two types with the H type being richer and more diverse than P type. No differences emerged between logged and unlogged of both types, indicating that the current intensity of disturbance does not seem to have a significant impact on the ground herbaceous layer. Since herbaceous species are an important component of the tropical forest diversity, further inventories must be conducted along a wider elevation gradient to make these results more robust and better observe species turn over patterns and beta diversity.

Grazing in temporary paddocks with hardy breed horses (Konik polski) improved species-rich grasslands restoration in artificial embankments of the Rhône river (Southern France)

Extensive horse grazing with hardy breeds is largely used in conservation management for restoring species-rich semi-natural grasslands in Europe. As an example, the Donzère-Mondragon Rhône river embankments (south-eastern France) where horse grazing with Konik polski succeeded to maintain high species richness in patches of open and short grassland, but failed for patches of tall grassland dominated by the grass tussock species Brachypodium phoenicoides . In response, an increase of herd density by the creation of temporary paddocks was applied in tall grassland patches. Grazing pressure over time between patches was estimated via GPS fixed to mares, biomass, plant species richness measurements and from multispectral photographs, the normalized Difference Vegetation Index (NDVI) was calculated. Finally, telemetric data were collected. We wondered if the use of extensive horse grazing with temporary paddocks occupation, increase plant species richness. After three years, our results show that the increase in stocking rate enabled a significant increase of plant species richness in the tall grassland patches, with a significant decline of B. phoenicoides in all paddocks. The NDVI was strongly correlated with herbaceous biomass and plant species richness, while the number of GPS points indicating the position of the mares was higher in areas where the NDVI was high. These results are discussed for improving horse grazing conservation systems efficiency on grasslands established in anthropized sites such as embankments and the use of the NDVI as an appropriate tool to help decision-making for large-scale applications.

A pan-Himalayan test of predictions on plant species richness based on primary production and water-energy dynamics

Spatial variation in plant species diversity is well-documented but an overarching first-principles theory for diversity variation is lacking. Chemical energy expressed as Net Primary Production (NPP) is related to a monotonic increase in species richness at a macroscale and supports one of the leading energy-productivity hypotheses, the More individuals Hypothesis. Alternatively, water-energy dynamics (WED) hypothesizes enhanced species richness when water is freely available and energy supply is optimal. This theoretical model emphasises the amount and duration of photosynthesis across the year and therefore we include the length of the growing season and its interaction with precipitation. This seasonal-WED model assumes that biotemperature and available water represent the photosynthetically active period for the plants and hence, is directly related to NPP, especially in temperate and alpine regions. This study aims to evaluate the above-mentioned theoretical models using interpolated elevational species richness of woody and herbaceous flowering plants of the entire Himalayan range based on data compiled from databases. Generalized linear models (GLM) and generalized linear mixed models (GLMM) were used to analyse species richness (elevational gamma diversity) in the six geopolitical sectors of the Himalaya. NPP, annual precipitation, potential evapotranspiration (derived by the Holdridge formula), and length of growing season were treated as the explanatory variables and the models were evaluated using the Akaike Information Criterion (AIC) and explained deviance. Both precipitation plus potential evapotranspiration (PET), and NPP explain plant species richness in the Himalaya. The seasonal-WED model explains the species richness trends of both plant life-forms in all sectors of the Himalayan range better than the NPP-model. Despite the linear precipitation term failing to precisely capture the amount of water available to plants, the seasonal-WED model, which is based on the thermodynamical transition between water phases, is reasonably good and can forecast peaks in species richness under different climate and primary production conditions.

Plant biodiversity in residential yards is influenced by people’s preferences for variety but limited by their income

Residential yards are a unique component of the urban environment and harbor high cultivated plant biodiversity; however, why and how people create yards with so many plant species is not well understood. To investigate this pattern, we studied the relationships between residents’ preferences, income, and yard plant biodiversity in the Salt Lake Valley, Utah, USA where most of the urban vegetation is intentionally cultivated. We conducted in-person interviews, distributed written surveys, and inventoried the biodiversity (i.e., genus and species richness) of ornamental herbaceous flowering plants and lawn plants in residential yards located in neighborhoods across income levels. We found that 95% of surveyed residents valued having ‘plants that create variety in the yard’ (‘variety’ left open to interpretation) and that 47% of interviewed residents expressed an emotional connection to variety. On average, general plant variety was more important to residents than high plant biodiversity (i.e., a specified type of variety), but they also exhibited a preference for neat monoculture lawns lacking in biodiversity and other types of variety. Residents’ preferences for general plant variety, and biodiversity specifically, were not necessarily reflected in their yards. Higher income households had greater flowering plant variety in terms of number of different flower colors, inflorescence types, and genera, but lower lawn species biodiversity due to a reduction in weedy species. Overall, our study shows that most residents in this region prefer plant variety in their yards more than biodiversity specifically, and that people with higher incomes can better achieve these preferences.

Biogeographic regionalization by spatial and environmental components: Numerical proposal.

Regionalization through the analysis of species groups offers important advantages in conservation biology, compared to the single taxon approach in areas of high species richness. We use a systematic framework for biogeographic regionalization at a regional scale based on species turnover and environmental drivers (climate variables and soil properties) mainly of herbaceous plant species richness. To identify phytogeographic regions in the Balsas Depression (BD), we use Asteraceae species, a family widely distributed in Seasonally Dry Tropical Forest (SDTF) and the most diverse of the vascular plants in Mexico. Occurrence records of 571 species were used to apply a quantitative analysis based on the species turnover, the rate of changes in their composition between sites (β-Simpson index) and the analysis of the identified environmental drivers. Also, the environmental predictors that influence species richness in the SDTF were determined with a redundancy analysis. We identified and named two phytogeographic districts within the SDTF of the BD (Upper Balsas and Lower Balsas). According to the multi-response permutation procedure, floristic composition of the two districts differs significantly, and the richness of exclusive species in Upper Balsas was higher (292 species) than in the Lower Balsas (32 species). The proportion of Mg and Ca in the soil and the precipitation of the driest three-month period were the environmental factors with greatest positive influence on species richness. The division of geographic districts subordinated to the province level, based on diverse families such as Asteraceae, proved to be appropriate to set up strategies for the conservation of the regional flora, since at this scale, variation in species richness is more evident. Our findings are consistent with a growing body of biogeographic literature that indicates that the identification of smaller biotic districts is more efficient for the conservation of biodiversity, particularly of endemic or rare plants, whose distribution responds more to microhabitats variation.

Ambient urban N deposition drives increased biomass and total plant N in two native prairie grass species in the U.S. Southern Great Plains.

Remnants of native tallgrass prairie experience elevated atmospheric nitrogen (N) deposition in urban areas, with potential effects on species traits that are important for N cycling and species composition. We quantified bulk (primarily wet) inorganic N (NH4+-N + NO3--N) deposition at six sites along an urban development gradient (6–64% urban) in the Dallas-Fort Worth metropolitan area from April 2014 to October 2015. In addition, we conducted a phytometer experiment with two common native prairie bunchgrass species––one well studied (Schizachyrium scoparium) and one little studied (Nasella leucotricha)––to investigate ambient N deposition effects on plant biomass and tissue quality. Bulk inorganic N deposition ranged from 6.1–9.9 kg ha-1 yr-1, peaked in spring, and did not vary consistently with proportion of urban land within 10 km of the sites. Total (wet + dry) inorganic N deposition estimated using bulk deposition measured in this study and modeled dry deposition was 12.9–18.2 kg ha-1 yr-1. Although the two plant species studied differ in photosynthetic pathway, biomass, and tissue N, they exhibited a maximum 2-3-fold and 2-4-fold increase in total biomass and total plant N, respectively, with 1.6-fold higher bulk N deposition. In addition, our findings indicate that while native prairie grasses may exhibit a positive biomass response to increased N deposition up to ~18 kg ha-1 yr-1, total inorganic N deposition is well above the estimated critical load for herbaceous plant species richness in the tallgrass prairie of the Great Plains ecoregion and thus may negatively affect these plant communities.

Effect of soil nutrient spatial heterogeneity by cutting disturbance on understory plant diversity in broadleaved-Korean pine forest in Changbai Mountain, China

The spatial variation of forest soil nutrients influences the species composition, distribution and diversity of forest plants, because soil nutrients are the most important environmental factors limiting the growth and survival of plants. We analyzed the effect of the spatial heterogeneity of soil nutrients on understory vegetation diversity in broadleaved-Korean pine forest, which had been undergone cutting disturbance. The results are of great significance in the sustainable management of the broadleaved-Korean pine forest and understanding the mechanism of correlation between heterogeneity and diversity. We sampled four plots of broadleaved-Korean pine forest in Jiaohe Forestry Bureau in Jilin province, China. Plot A, a control, was unlogged broadleaved-Korean pine forest. In plot B, C and D, forest was cut at 20%, 35% and 55% of the intensity in 2011. Cutting intensity influenced significantly on total nitrogen (TN), total phosphorous (TP), pH, soil organic matter (SOM), nitrate nitrogen (NN) and ammoniacal nitrogen except total potassium (p < 0.05). The values of TN, TP, pH and SOM showed that their quantities could decrease as cutting intensity increased. Species richness and diversity index of woody plants could increase in proportion to the cutting intensity, but species richness and diversity index of herbaceous plants might tend to decrease in early spring and summer. Coefficient of variation of TN, TP, SOM and NN could have either a positive or negative correlation with α-diversity indices of woody and herbaceous plants, while the other soil nutrient indices could have no correlation with diversity indices.

Contribution of Agro-Environmental Factors to Yield and Plant Diversity of Olive Grove Ecosystems (Olea europaea L.) in the Mediterranean Landscape

Olive cultivation (Olea europaea L.) is one of the most significant sources of income for agricultural areas in the Mediterranean basin, and the olive oil industry as well as the environmental protection are an important part of the Greek agricultural sector. Generalized Linear Models were applied in order to investigate the predictive strength of several biodiversity components and agro-environmental factors for yield and herbaceous plant diversity (species richness) in organic and conventional olive groves of Greece. Our study highlights an increase in yields of organic olive groves by increasing manure application and the earthworms’ density. In the conventional olive groves, yields increase by increasing soil organic matter and the application of inorganic fertilizer N. Also, the herbaceous plant species richness increases with increasing the Shannon diversity index of herbaceous plants, the field area, the application of organic fertilizer K and the manure in organic olive groves. As for the conventional ones, herbaceous plant species richness increases with the increase of the application of inorganic fertilizer N. Moreover, some plant species could be regarded as indicators of the differently managed olive groves. Conclusively, this study contributes to the integration of biodiversity conservation with ecologically sustainable agriculture and conservation of agroecosystem. Finally, it could be utilized as a decision and management tool to the scientific and agricultural community reinforcing the knowledge about the agro-environmental impact in olive grove management systems.