Herbaceous Species Composition Research Articles

High fire frequency in California chaparral reduces postfire shrub regeneration and native plant diversity

AbstractFire is crucial for maintaining species diversity and resilience in fire‐adapted shrublands of the world's Mediterranean climate zones (MCZs), which include the chaparral shrublands of the North American MCZ. Chaparral is adapted to high‐intensity burning, with relatively long intervals between fires (30–100 years) typifying undegraded conditions. Modern fire frequencies are much higher in chaparral, driven largely by high densities of human ignitions and coincidence between ignitions and severe weather conditions. This change in the fire regime has major implications for biodiversity, leading to exotic invasion, decreased ecosystem services, and potential type conversion of shrubland to grassland dominated by exotic species. We studied the impact of increased fire frequencies on the composition and abundance of herbaceous and woody species in the Interior Coast Range of northern California. Our study area is one of the most frequently burned areas in California, which allowed us to investigate higher fire frequencies than previously published in the scientific literature for California. We surveyed fifty‐four 250‐m2 plots to assess changes in plant community composition and postfire regeneration of chaparral shrubs across a wide range of fire frequencies, including plots that have burned up to six times in the past 30 years. Our findings reveal that short‐interval fires significantly reduced postfire native woody regeneration, with obligate seeding species experiencing a 99% reduction and facultative species showing an 83% reduction in regeneration in the most frequently burned plots. Moreover, the overall marginal effect of one additional fire since 1985 decreased the proportion of native species cover by 12% and both richness and Shannon diversity by 4%. Consequently, areas with higher fire recurrence supported a more structurally and botanically homogeneous landscape dominated by a homogeneous group of non‐native species.

Effects of livestock grazing on herbaceous species composition and biomass in the Simien Mountains National Park, Ethiopia

Abstract Simien Mountains National Park (SMNP) provides valuable ecosystem services. Despite its ecological values, the effect of livestock-free grazing on habitat quality has not been investigated. The present study aimed to examine how livestock grazing within the Simien Mountains National Park affects herbaceous plant diversity and biomass. The study was carried out from February 2019 to July 2019 in livestock-grazed and ungrazed sites. In each grazing site, ten transects with a length of 25 m were set monthly. Along each transect line, five temporary sample plots (1 m2) were established. For aboveground biomass estimation, grass and forbs were clipped from 0.25 m2 in every sample plot, whereas below-ground biomass was estimated from two soil core (diameter = 6.35 cm, depth =20 cm) samples in each transect. Species diversity and evenness were estimated using the Shannon-Wiener diversity and evenness index. A total of 43 plant species belonging to 20 families were identified. Aboveground biomass and below-ground biomass were significantly higher in ungrazed areas than in the grazed ones. Similarly, species diversity and richness were relatively lower in the grazed areas than in ungrazed areas. The study concluded that livestock grazing has affected the habitat by degrading the vegetation diversity and biomass production. Therefore, stakeholders should be encouraged to innovate appropriate grazing management technologies for the local livestock ranchers to support the conservation efforts of the park.

Farm management and landscape context shape plant diversity at wetland edges in the Prairie Pothole Region of Canada.

Evaluating the impacts of farming systems on biodiversity is increasingly important given the need to stem biodiversity loss, decrease fossil fuel dependency, and maintain ecosystem services benefiting farmers. We recorded woody and herbaceous plant species diversity, composition, and abundance in 43 wetland-adjacent prairie remnants beside crop fields managed using conventional, minimum tillage, organic, or perennial cover (wildlife-friendly) land management in the Prairie Pothole Region. We used a hierarchical framework to estimate diversity at regional and local scales (gamma, alpha), and how these are related through species turnover (beta diversity). We tested the expectation that gamma richness/evenness and beta diversity of all plants would be higher in remnants adjacent to perennial cover and organic fields than in conventional and minimum tillage fields. We expected the same findings for plants providing ecosystem services (bee-pollinated species) and disservices (introduced species). We predicted similar relative effects of land management on alpha diversity, but with the expectation that the benefits of organic farming would decrease with increasing grassland in surrounding landscapes. Gamma richness and evenness of all plants were highest for perennial cover, followed by minimum tillage, organic, and conventional sites. Bee-pollinated species followed a similar pattern for richness, but for evenness organic farming came second, after perennial cover sites, followed by minimum tillage and conventional. For introduced species, organic sites had the highest gamma richness and evenness. Grassland amount moderated the effect of land management type on all plants and bee-pollinated plant richness, but not as expected. The richness of organic sites increased with the amount of grassland in the surrounding landscape. Conversely, for conventional sites, richness increased as the amount of grassland in the landscape declined. Our results are consistent with the expectation that adopting wildlife-friendly land management practices can benefit biodiversity at regional and local scales, in particular the use of perennial cover to benefit plant diversity at regional scales. At more local extents, organic farming increased plant richness, but only when sufficient grassland was available in the surrounding landscape; organic farms also had the highest beta diversity for all plants and bee-pollinated plants. Maintaining native cover in agroecosystems, in addition to low-intensity farming practices, could sustain plant biodiversity and facilitate important ecosystem services.

Determining the community composition of herbaceous species from images using convolutional neural networks

Global change has a detrimental impact on the environment and changes biodiversity patterns, which can be observed, among others, via analyzing changes in the composition of plant communities. Typically, vegetation relevées are done manually, which is time-consuming, laborious, and subjective. Applying an automatic system for such an analysis that can also identify co-occurring species would be beneficial as it is fast, effortless to use, and consistent. Here, we introduce such a system based on Convolutional Neural Networks for automatically predicting the species-wise plant cover. The system is trained on freely available image data of herbaceous plant species from web sources and plant cover estimates done by experts. With a novel extension of our original approach, the system can even be applied directly to vegetation images without requiring such cover estimates. Our extended approach, not utilizing dedicated training data, performs similarly to humans concerning the relative species abundances in the vegetation relevées. When trained on dedicated training annotations, it reflects the original estimates more closely than (independent) human experts, who manually analyzed the same sites. Our method is, with little adaptation, usable in novel domains and could be used to analyze plant community dynamics and responses of different plant species to environmental changes.

Grazing effects on vegetation dynamics in the savannah ecosystems of the Sahel

BackgroundThe savannah ecosystems of Sahel have experienced continuous and heavy grazing of livestock for centuries but still, their vegetation response to grazing pressure remains poorly understood. In this study, we analysed the herbaceous plant dynamics, measured by species diversity, composition, cover, and biomass in response to grazing pressure in the savannah ecosystems of Sahel. In Senegal, we selected four savannah sites represented with high, moderate, light and no grazing intensity levels. Transect survey methods were used for sampling the vegetation data within each of the sites. Species richness and composition were analysed using species accumulation curve and multivariate analyses. Furthermore, we used General Linear Models and a piecewise Structural Equation Model (pSEM) to examine the relationships between grazing intensity, vegetation cover, diversity and biomass.ResultsThe herbaceous species diversity and composition varied significantly among the different grazing intensity levels (p <0.001). The plant species composition shifted from the dominance of grass cover to the dominance of forb cover with increasing grazing pressure. Moreover, the attributes of species diversity, herbaceous biomass, and ground cover were higher on sites with low grazing than sites with high and moderate grazing intensity. Across all sites, species diversity was positively related to total biomass. The pSEM explained 37% of the variance in total biomass and revealed that grazing intensity negatively influenced total biomass both directly and indirectly through its negative influence on species diversity.ConclusionsManaging grazing intensity may lead to higher plant production and higher mixed forage establishment in the dryland savannah ecosystems. This information can be used to support land management strategies and promote sustainable grazing practices that balance the needs of livestock with the conservation of ecosystem health and biodiversity.

The dynamics of vegetation diversity and biomass under traditional grazing in Ethiopia's Somali rangeland.

Traditional grazing management practices are central to rangeland productivity and biodiversity. However, the degradation of rangelands and loss of ecosystem services have raised concerns about the future of pastoralism as a form of land use. It is imperative to understand how these practices influence vegetation attributes, e.g., herbaceous species diversity and composition, growth forms (grass, forbs), life form (annuals, perennials), tree metrics (density, canopy cover, and biomass). This study evaluates vegetation shifts under three grazing management practices-enclosures, open grazing, and browsing lands-in the Somali pastoral ecosystem of Ethiopia. Enclosures exhibited the highest diversity in herbaceous species, with open grazing lands favoring forbs and annuals. Distinct compositional shifts in herbaceous species were observed across regimes, especially in grass and annuals. Enclosures had three times higher herbage biomass of open grazing and double that of browsing management practice. Conversely, browsing management practices presented optimal wood biomass, density, and canopy cover. The results highlight that a transition to combined enclosure and browsing practices can elevate plant production and diversity, benefiting the Somali rangeland economy. Consequently, dryland restoration should incorporate indigenous knowledge to ensure future rangeland sustainability and biodiversity preservation.

Grazing intensity effects on rangeland condition and tree diversity in Afar, northeastern Ethiopia

This study assessed the effects of different grazing pressures (light, moderate and heavy) on rangeland condition and woody species diversity in northeastern Ethiopia. Rangeland condition was analyzed using common protocols for the assessment of semi-arid rangelands. A total of 4 grasses, 5 herbs, 1 sedge and 14 tree and/or shrub species were identified. Results show that grazing intensity had detrimental effects on condition of the rangeland, and caused undesirable changes in herbaceous species composition. The contribution of undesirable plants to herbaceous aboveground biomass was particularly high (40 %) compared to the 30 % contributed by highly desirable species. Nearly all measures of range condition were negatively affected by grazing. Grass composition, number of seedlings and age distribution, basal and litter cover, soil erosion and compaction decreased significantly as grazing intensity increased. Species richness and diversity (Hill numbers) of woody plants were reduced significantly by grazing. The overall condition of the rangeland was generally poor. The pastoralists perceived that recurring droughts, heavy continuous grazing and inappropriate management interventions, and bush encroachment were the main contributing factors that led to overgrazing and rangeland deterioration in the area. In conclusion, our study shows that livestock grazing in northeastern Ethiopia degrade range condition and woody vegetation, and its effects are sever under moderate and heavy grazing. Management measures such as resting of the rangelands preferably with stock exclusions for 6–12 months or protecting heavily degraded or sensitive areas from livestock activity and reseeding may be the viable options to mitigate declines in range conditions.

Phytodiversity of Herbaceous Flora in the Grasslands of Jannaram Division, Kawal Tiger Reserve, Telangana, India

Aims: To study the diversity and composition of herbaceous species in the grasslands of Jannaram division, Kawal Tiger Reserve, Telangana, India.&#x0D; Place and Duration of Study: Grasslands of Jannaram division, Kawal Tiger Reserve, Telangana, July 2022 to August 2023.&#x0D; Methodology: The study was carried out by laying out 223 sample plots in the Jannaram division by dividing Jannaram division into 3 ranges. The plot size was 1 x 1 m. Varied diversity indices such as Simpson, Shannon–Weiner, species evenness, and IVI were calculated according to standard formulae. Vegetation analysis and IVI value of each species were calculated and analysed.&#x0D; Results: A total of 65 species, comprising 53 genera and 21 families, were reported. The dominant family in the study area was Poaceae, followed by Fabaceae, Malvaceae, Acanthaceae, Asteraceae and Euphorbiaceae. The Shannon–Weiner index was 3.46 and the Simpson index was 0.05, indicating high diversity with less dominance of herb layer in the study area. Top five species holding highest IVI value are Iseilema laxum (29.94), Cynodon barberi (12.19), Eragrostis amabilis (12.15), Dichanthium annulatum (11.20), and Apluda mutica (10.21).&#x0D; Conclusions: This research produced fundamental information regarding the types of herbaceous plants and grasses present at the Jannaram, Kawal Tiger Reserve. This would serve as a guide to the systematists, ethnobotanists, amongst several others researchers who are interested in identifying.

Assessment of Herbaceous Plant Composition, Diversity, and Indicator Species in the Juniperus drupacea Forest Openings of the Mountain Parnonas in Greece

A significant challenge in community ecology is the establishment of ecological baselines, which permit the evaluation of the variations in ecological dynamics at different temporal and spatial scales. To our best knowledge, few studies have been conducted in the forest openings of Mt. Parnon to establish a baseline for future monitoring. Hence, a floristic study of the herbaceous plant species composition, diversity, cover, and biomass was conducted in the forest openings of the Mt. Parnon-Natura 2000 Site in Greece to develop an ecological baseline that could be utilized in decision making for conservation and the sustainable use of forest biodiversity and ecosystem services in the forest ecosystem of Mt. Parnon. In the spring season, a thorough floristic survey was performed on Mt. Parnon for two consecutive years, 2021 and 2022. Herbaceous plant composition, diversity, cover, biomass, and plant indicator species (indicator value analysis) in the forest openings of Mt. Parnon were assessed. In the studied area, 63 plant species belonging to 58 genera from 20 families were recorded. The most numerous families were Asteraceae and Poaceae, followed by Fabaceae. Variable plant diversity, herbaceous plant cover, and produced biomass were recorded in different sites. It is noteworthy that some plant species could be regarded as indicators of the sites in the study area [Geranium molle L., Cerastium candidissimum Correns, Vicia villosa Roth, Euphorbia myrsinites L., Odontarrhena muralis (Waldst. &amp; Kit.) Endl., Medicago lupulina L., Lotus corniculatus L., Crepis fraasii Sch. Bip., Bellis sylvestris Cirillo, and Trifolium stellatum L.], and information about these indicators, including Ellenberg type indicator values, is also provided. This study contributes to the understanding of the relevant ecological topics and provides key elements that could be utilized in decision making for the conservation and sustainable use of forest biodiversity and ecosystem services on Mt. Parnon.

Diversity, Composition and Economic Importance of Herbaceous Plants within the Federal Polytechnic Kaura Namoda Campus, Zamfara State, Nigeria.

The diversity, composition and economic importance of herbaceous species within the federal polytechnic Kaura Namoda, Zamfara State was studied. The study's objective was to identify, document and evaluate the diversity and abundance of herbaceous species in the study area. The point-centered quarter (PCQ) method was employed in each sampling point. All nearest living herb species encountered were listed. Data obtained were quantitatively analyzed for Relative density (RD) and relative frequency (RF). Species diversity was calculated using Simpson’s index and the Shannon-Weiner index. A total of 64 species of herb were identified belonging to 19 Families. Acanthaceae, Aizoaceae, Cleomaceae, Connaraceae, Laminaceae, Oxalidaceae, and Plantaginaceae had (1) species each. Convolvulaceae, Cucurbitaceae and Euphobiaceae had (2) species each. Apocynaceae, Asteraceae, Malvaceae, Pedaliaceae and Poaceae had (3) species each. Solonaceae is the only family with (4) species. Fabaceae is the only family with the highest number of species (32). A total of 494 individuals of herbaceous species were in the study area. Site A has the highest number of individuals (117), followed by Site D (103), Site C (95) and E (82). Tephrosia pedicellata has the highest species density of 3.2. Leptadenia hastata, Centaurea perrottetii, Gynandropsis gynandra, Euphorbia balsamifera, Senna obtusifolia, Abrus precatorius, Desmodium velutinum, Crotalaria goreensis, Crotalaria pallida var.obovata, Tephrosia pedicellata, Indigofera oblongifolia, Tephrosia vogelii, Tephrosia linearis, Biophytum petersianum, Sesamum radiatum, Solanum lycopersicum has the highest Frequency (100%). Senna tora has the highest relative abundance (5), and Euphorbia balsamifera has a Relative Density of 3.8. Euphorbia balsamifera has the highest relative density of 5, and Ipomea asarifolia has an IVI of 7. Shannon Weiner's diversity index for herbaceous species showed a total of 4.0097. Herbaceous plants are of economic importance; they serve as food, fooder, medicine, fuel, and other purposes. We recommended that there is a need for the conservation of herbaceous species within the Polytechnic to avoid harvesting the herbs for medicinal purposes and animals foraging on the grasses.

Grazing and defoliation timing effects in Great Plains ponderosa pine woodland following a large summer wildfire

There remains a high level of ambiguity around post-fire grazing management. The Lodgepole Complex fire burned 109,346 ha in east-central Montana in July 2017, including areas previously burned in 2003 by the Bureau of Land Management for fuels mitigation. We hypothesized that herbaceous productivity and species composition in ponderosa pine woodlands are resistant to moderate grazing and timing of defoliation the first growing season after fire. Eight exclosures (25 × 15 m) were built, 4 on reburned area and 4 on wildfire area. To determine grazing effects, a 15 × 10 m sampling area in each exclosure was paired with a grazed section outside the exclosure. Additionally, four 5x10-m plots were established within each exclosure and were mowed to 10 cm in June, July, August, or not mowed to determine seasonal defoliation effects. Differences between grazed and nongrazed sites in 2019 were limited. There was a trend for less old dead biomass in grazed than nongrazed treatments. Species richness was greater on grazed sites than nongrazed or reburn sites. Native species richness was greater on grazed sites than nongrazed sites and reburn sites had an intermediate level of native species richness. Standing crop was reduced by defoliation, with current year and perennial grass biomass being unaffected. The reduction in standing crop was driven by less old dead biomass on defoliated plots. June defoliation reduced C3 grasses and increased C4 grasses, and June and July defoliation each reduced annual grasses. Simpson’s and native Simpson’s diversity were greater on defoliated plots. Results indicate ponderosa pine woodland is resilient to moderate post-fire grazing.

Effects of Euphorbia nubica Encroachment on Herbaceous Species Composition in Borana Zone, Southern Ethiopia

The study was conducted in three districts of Borana Zone towards the end of the growing season, with the objective of examining the effects of encroaching Euphorbia nubica species on their encroached and non-encroached areas of herbaceous species composition in Borana rangelands and analysis the perception of pastoralist on encroaching of Euphorbia nubica species. A survey was conducted from two PA of each district by interviewed 34 pastoralists from each PA and a total 204 households were interviewed purposively to analysis pastoralist perceptions. Also, 20 m x 20 m main plots were laid out in encroached and non-encroached areas of Euphorbia nubica species. Then four sub-quadrants with 1 m x 1 m size were randomly placed in this main plot to determine herbaceous composition. The collected data was analyzed using General Linear Model (GLM) procures for significance test at an alpha level of 0.05, and the least significant differences test was used for mean separation for comparison of impacts of encroaching species. As Pastoralists’ perception, Euphorbia nubica species are less important and increased in the rangelands by reducing rangeland production and productivity. In this study, the proportion of basal and litter cover was significantly different (P &lt; 0.05) between non-encroached and encroached areas of Euphorbia nubica species. Also, grass and forbs of dry matter and diversity were significant (P &lt; 0.05) among encroached and non-encroached areas of Euphorbia nubica species. Both pastoral perception and analyzed results indicate that the encroachment of Euphorbia nubica species has an impact on rangeland productivity by reducing productive grass species and increasing less desirable forbs species. Keywords: Encroached, Non-encroached, Grass, non-grass and dry matter yield DOI: 10.7176/JNSR/13-12-01 Publication date: June 30 th 2022

Short-term responses of herbaceous vegetation to bush clearing in semi-arid rangelands of South Africa

Bush thickening reduces herbaceous species diversity and forage production, leading to a decline in grazing capacity. Hence, altering the micro-climate and woody-grass competition in bush-encroached rangelands using bush clearing is instrumental for the restoration of herbaceous vegetation. The short-term recovery potential of herbaceous species composition, basal cover and biomass production was assessed following bush clearing at Makapaanstad, North West province, South Africa. The mean density was 6908 woody plants ha−1, with Vachellia tenuispina encroaching at 6301 plants ha−1. Paired observations were conducted in bush-cleared sites (where woody plants were cut using saws, with stumps treated with picloram at 1% concentration) and uncleared sites (where the woody cover was left intact). Forty-nine different herbaceous species were recorded, with grasses being more abundant in cleared (62%) than in uncleared sites (50%). Herbaceous species showed interspecific responses, with Brachiaria eruciformis and Panicum coloratum colonising in cleared sites, whereas the frequency of other species remained comparable between cleared and uncleared sites. Graminoids, largely bunch grasses, had a significantly greater basal cover in cleared (496 cm2 m−2) compared to uncleared (301 cm2 m−2) sites. Likewise, total biomass production was significantly (p = 0.05) higher in cleared (760 kg DM ha−1) than in uncleared (636 kg DM ha−1) sites. The principal component analysis (PCA) showed that most herbaceous species were associated with soils having high total nitrogen and nitrite. Seedlings of forbs (r2 = 0.81), grasses (r2 = 0.97) and succulents (r2 = 0.98) were highly associated with nitrate-rich soils. Our results revealed that even at a short term, bush clearing is important for the restoration of herbaceous vegetation.

Reinvasion of Native Invasive Trees After a Tree-Thinning Experiment in an African Savanna

Woody plant encroachment has serious negative consequences for ranchers because of the reduction in herbaceous fodder for domestic livestock. A long-term monitoring of a tree-thinning experiment was established near Magudu (northern KwaZulu-Natal, South Africa) in 1990. The objective of this experiment was to determine the optimal tree density that would maximize grass production while benefiting grasses from nitrogen fixation, hydraulic lift, and/or shade from the leguminous trees. The initial dominant species was the nitrogen-fixing tree, Dichrostachys cinerea. There were 12 plots (6 pairs) with trees removed to approximate 0, 179, 277, 428, and 625 trees ha−1, with 1 pair left as a control (unmanipulated). One plot of each replicate (except the controls) was treated with short-acting herbicide (picloram) once in 1990. We collected data on herbaceous cover and species composition, tree species composition, sizes, and mortality. We also used remote sensing to examine the patterns of herbaceous cover. Herbaceous biomass decreased as tree density increased. After 30 yr, the same dominant tree species (D. cinerea) had reinvaded all the removal plots despite the fact that several encroaching species (Vachellia karroo, V. tortilis, V. nilotica) occurred in these plots. These D. cinerea trees were mostly less dense and contained many more juvenile individuals in the cleared and partially cleared plots than those in the control plots after 30 yr. Should maximizing herbaceous cover be the goal, repeated brush management would be necessary to maintain adequate control of woody plants in these savannas.

Gyepes, virágos takarónövényzettel növelhető a lágyszárú diverzitás az agrárerdészetben

Intensive agricultural technologies lead to a simplification of landscape and a decrease in biodiversity. Besides economic benefits, alley cropping might increase species richness, improving pollination in agriculture. In this research, a traditional apricot plantation combined with crop fields was studied in Burgenland, focused on herbaceous diversity and species composition, which have a crucial role in promoting pollination. The vegetation of the grassy strips under the tree rows was compared to control grass and tree plantation habitats. The results show that the loose canopy layer of the fruit trees promotes the appearance of several herbaceous species, which results in a more diverse understory layer compared to the control tree plantation. However, the intensity of the management significantly impacts the species richness and composition of the understory vegetation.

Floristic composition and potential invasiveness of alien herbaceous plant in Western Mexico

Introduction: Numbers of alien plant species are rising around the globe, but not all of them become invasive. Whereas introductions have been documented for several decades in some regions of the world, knowledge on alien species in Western Mexico is limited. Here, we study roadside vegetation along an elevational gradient, which includes a protected area. Objective: We analysed the floristic composition of herbaceous alien species, their distribution patterns, and their relationship with various environmental factors. A relative importance value index (IVI) identified the most important and, therefore, probably invasive taxa. Methods: During 2017 and 2018, roadside vegetation was documented with 4-6 transects every 300 altitudinal meters, from 0 to 2 100 m, for a total of 37 transects. Each transect consisted of five 1 m² plots. All herbaceous species were registered and alien taxa identified. A cluster analysis distinguished grouping of species based on elevation. The potentially invasive species were identified by their IVI, based on the sum of relative frequency and density values. The influence of environmental variables was analysed with a canonical correspondence analysis. Results: Most alien species were grasses; other families were represented by one or two species. The species were grouped into three main clusters. The first group included rare species, the second consisted of species restricted to higher altitudes, and the third group were tropical taxa with a distribution from sea level to medium altitudes. The most important potentially invasive species were: Urochloa maxima, Melinis repens, Eragrostis ciliaris and Cynodon dactylon, all African grasses introduced for grazing. The IVI of the species was related to tree cover, leaf litter depth and surface stone cover for some species and, for others, to soil compaction, distance to major roads and elevation. Conclusions: The alien ruderal species clustered according to the general climate (temperate vs. tropical). Grasses of African origin are of highest concern as invasive species. Although most introductions are related to human disturbance, each species becomes dominant under certain environmental conditions. Thus, management programs must be specifically adjusted to each individual invasive alien.

Effect of tree canopy on herbaceous vegetation and soil characteristics in semi-arid forests of the Aravalli hills

Herbaceous vegetation is of great ecological importance and responds quickly to environmental changes. The present study was aimed to understand the variation in herbaceous species composition, biomass and soil physico-chemical properties in the naturally formed gap and the understory of semi-arid forests in the Aravalli hills. Four permanent plots consisting of the gap as well as the understory were established. To study herbs phytosociological attributes and biomass, 10 quadrats of 0.5 × 0.5 m size were laid in each plot. For soil physico-chemical properties, 5 soil samples were collected randomly at 0–10 cm depth from each plot. Relationships among biodiversity indices, herbaceous biomass and soil physico-chemical properties were determined using Redundancy Analysis (RDA) and correlation analysis. Across the sites, Poaceae was the dominant family. All species showed a contagious distribution pattern. In the understory, Importance Value Index (IVI) was the recorded highest for Oplismenus burmannii, ranging from 138 to 230.5 while in the gap, it was the highest for Achyranthes aspera (56.15) followed by Eragrostis ciliaris (53.1). Both sites included, herbaceous community biomass in the gap ranging from 700 to 900 g m−2 while in the understory it ranged from 30 to 70 g m−2. Cenchrus ciliaris (597.97 g m−2) and Chrysopogon sp. (391.2 g m−2) contributed a major proportion of herbaceous community biomass in the gap. Oplismenus burmannii (52.2 g m−2), Dipteracanthus prostratus (16.6 g m−2) and Cynodon dactylon (9.6 g m−2) contributed a major proportion of herbaceous community biomass in the understory. The understory soil had significantly (p < 0.05) higher soil moisture (%), electrical conductivity (EC), soil organic carbon (SOC) and soil total nitrogen (TN) compared to the gap. Even though canopy had positive effects on soil physico-chemical properties, it has negatively influenced herbaceous species composition, diversity and biomass, due to significant reduction in solar radiation reaching the ground.

Effect of thinning intensity on understory herbaceous diversity and biomass in mixed coniferous and broad-leaved forests of Changbai Mountain

BackgroundHerbs are an important part of the forest ecosystem, and their diversity and biomass can reflect the restoration of vegetation after forest thinning disturbances. Based on the near-mature secondary coniferous and broad-leaved mixed forest in Jilin Province Forestry Experimental Zone, this study analyzed seasonal changes of species diversity and biomass of the understory herb layer after different intensities of thinning.ResultsThe results showed that although the composition of herbaceous species and the ranking of importance values were affected by thinning intensity, they were mainly determined by seasonal changes. Across the entire growing season, the species with the highest importance values in thinning treatments included Carex pilosa, Aegopodium alpestre, Meehania urticifolia, and Filipendula palmata, which dominated the herb layer of the coniferous and broad-leaved mixed forest. The number of species, Margalef index, Shannon-Wiener index and Simpson index all had their highest values in May, and gradually decreased with months. Pielou index was roughly inverted “N” throughout the growing season. Thinning did not increase the species diversity. Thinning can promote the total biomass, above- and below-ground biomass. The number of plants per unit area and coverage were related to the total biomass, above- and below-ground biomass. The average height had a significantly positive correlation with herb biomass in May but not in July. However, it exerted a significantly negative correlation with herb biomass in September. The biomass in the same month increased with increasing thinning intensity. Total herb biomass, above- and below-ground biomass showed positive correlations with Shannon-Winner index, Simpson index and Pielou evenness index in May.ConclusionsThinning mainly changed the light environment in the forest, which would improve the plant diversity and biomass of herb layer in a short time. And different thinning intensity had different effects on the diversity of understory herb layer. The findings provide theoretical basis and reference for reasonable thinning and tending in coniferous and broad-leaved mixed forests.

Predicting the potential distribution of aquatic herbaceous plants in oligotrophic Central Amazonian wetland ecosystems

Aquatic herbaceous plants are especially suitable for mapping environmental variability in wetlands, as they respond quickly to environmental gradients and are good indicators of habitat preference. We describe the composition of herbaceous species in two oligotrophic wetland ecosystems, floodplains along black-water rivers (igapó) and wetlands upon hydromorphic sand soils (campinarana) in the Parque Nacional do Jaú and the Reserva de Desenvolvimento Sustentável Uatumã in Central Amazonia, both protected areas. We tested for the potential distribution range (PDR) of the most frequent species of these ecosystems, which are the ones that occurred in at least two of the sampled wetlands, using species distribution models (SDMs). In total, 98 aquatic herbaceous species were recorded, of which 63 occurred in igapós and 44 in campinaranas. Most igapó species had ample PDRs across the Neotropics, while most campinarana species were restricted to the Amazon Basin. These results are congruent with studies that described similar distribution patterns for tree and bird species, which emphasizes a high degree of endemism in Amazonian campinaranas. However, we also found differences in the potential distribution of species between the two protected areas, indicating high environmental variability of oligotrophic ecosystems that deserve further investigation to develop effective measures for their conservation and protection.

The Effect of Continuous Grazing on Herbaceous Species Composition, Basal Cover and Production on Three Soil Types in the North West Province, South Africa

Rangeland health is normally measured by soil condition, grass species composition as well as its acceptability to grazing herbivores. The impact of grazing on community structure and ecosystem functioning is a key issue for rangeland management in order to maximize livestock production and sustainability of the operations. Year-round continuous grazing is the management strategy used in the communal areas of the North West Province of South Africa. In this study the effect continuous grazing on herbaceous species composition, basal cover and production on different soil types was tested. It was clear from the results that the effect of continuous grazing was the biggest on the andesitic soils (high clay), then the diabase soils (medium clay), whilst the effect on the quartzite soils was limited to even positive. The end result was that the different soil types in a continuous grazing system led to serious selective grazing in this study.