Herbaceous Communities Research Articles

Phylogenetic structure and diversity of herbaceous communities in the conifer forests along an elevational gradient in Luya Mountain, Shanxi, China

Phylogenetic structure and diversity of herbaceous communities in the conifer forests along an elevational gradient in Luya Mountain, Shanxi, China

Community-Level Impacts of Management and Disturbance in Western Michigan Oak Savannas

Abstract Midwestern oak savanna systems are typically defined by their open canopy and the co-existence of scattered mature oak trees and a ground layer dominated by herbaceous vegetation. The structure of these systems is thought to be primarily maintained by disturbance such as fire. In this study we examined the plant community of 21 different oak savanna sites in western Lower Michigan, U.S.A., across a coarse disturbance gradient created by different management practices. Herbaceous community composition differed significantly across a variety of management approaches, while overall diversity remained similar. Indicator species analysis (ISA) identified several species commonly associated with mixed oak forest understories (e.g., Maianthemum canadense) as indicators for recently abandoned oak savanna sites, whereas the indicators identified for managed or heavily disturbed sites included common savanna-associates (e.g., Lupinus perennis). Variation in soil characteristics (C:N ratio and pH) and canop...

Еколого-ценотичний аналіз трав'яних угруповань Аnthriscus sylvestris (Apiaceae) в умовах Лісової зони України

Еколого-ценотичний аналіз трав'яних угруповань Аnthriscus sylvestris (Apiaceae) в умовах Лісової зони України

Grazing and temporal turnover in herbaceous communities in a Mediterranean landscape

AbstractQuestionWhat are the direct and indirect effects of cattle grazing on temporal turnover in Mediterranean herbaceous communities, and are there differences between species (taxonomic) and functional turnover rates? Are turnover rates related to changes in precipitation patterns?LocationThe long term ecological research (LTER) station, Ramat Hanadiv Nature Park, Israel.MethodsWe used data from a Mediterranean LTER site to analyse temporal turnover in herbaceous communities under cattle grazing and control conditions, while accounting for the potential effects of precipitation and woody cover. We analysed two types of temporal turnover: taxonomic turnover (changes in species composition) and turnover in functional traits (changes in the relative abundance of species with different functional traits).ResultsWe found that communities exhibited rapid taxonomic turnover between sampling years, which was mostly explained by changes in precipitation patterns. Furthermore, there was a strong and consistent directional trend in taxonomic turnover (21% per decade) throughout the study period, which was correlated with a long‐term trend of decreasing precipitation. This trend, however, was not significantly explained by grazing, woody cover change or their interaction. Grazing did have a significant effect on short‐term turnover rates, but its effects varied in both direction and magnitude among sites located in different habitats. Temporal turnover in functional traits was much slower than taxonomic turnover, and was also inconsistent among traits and sites. Grazing reduced the bi‐annual turnover rates in the composition of different life forms, and reduced the decadal turnover rate in the composition of different height groups in the community.ConclusionsThe results of this analysis suggest that the effect of cattle grazing on the temporal dynamics of herbaceous communities in Mediterranean ecosystems is habitat‐ and trait‐specific, and unrelated to changes in woody cover. In contrast, inter‐annual changes in precipitation patterns have a much stronger effect on turnover rates. The relationship between temporal species turnover and precipitation in these communities is therefore in line with modern co‐existence theory, by which fluctuating environmental conditions facilitate long‐term species co‐existence.

Nitrogen effects on plant species richness in herbaceous communities are more widespread and stronger than those of phosphorus

Both nitrogen (N) and phosphorus (P) enrichment are known to impact plant diversity globally. Recent studies suggest that P enrichment may be as important, or even more important, as a driver of terrestrial plant species loss as N enrichment. However, the generality and relative contribution of these critical nutrients to species losses remains unclear. Here, we quantitatively compared effects of N, P and combined NP enrichment on species richness of natural and semi-natural herbaceous ecosystems across the world in a meta-analysis of 189 long-term nutrient addition experiments in the field. Our experiment-based approach shows that, across terrestrial and wetland ecosystems, N and NP enrichment had widespread and strong negative effects on plant species richness. N reduced plant species richness across experiments by on average 16% (p<0.001), while P did not (on average 3%, NS). Combined NP enrichment also reduced species richness, by on average 16% (p=0.009), with the dominant effect statistically attributed to N. N enrichment effects were greater in China than in Europe and America, which may be explained by background atmospheric N deposition rates and earlier species losses in Europe and America. P enrichment reduced species numbers only in the most species-rich communities and even increased species numbers at high latitudes. All nutrient enrichment combinations (N, P, NP) stimulated aboveground biomass production, and biomass-mediated mechanisms are likely to have contributed to reported species losses. Our findings demonstrate that for the protection of the world's herbaceous plant diversity, it is of the highest priority that N loads be drastically reduced.

GEOECOLOGICAL BASIS FOR THE ORGANIZATION OF MONITORING OF THE NORTHERN URBANIZED TERRITORIES (BY THE EXAMPLE OF PETROZAVODSK)

The Geochemistry of the snow cover, soils and near-surface sediments, groundwater,biogeochemical and morphological characteristics of herbaceous communities in different functional zones of the city were studied in Petrozavodsk. Studies have shown that in precipitation the high content of K+, Ca2+, Na + , Cl - , SO42-, Fe. All samples of snow contaminated with petroleum products. Тhe high content of Cu detected in all samples of snow among the heavy metals. Sustainable nitrate contamination of groundwater is typical for built-up areas of the city. Water of many springs bears signs of acidification. Periodically determined high concentrations of different elements. But stable anomalies in groundwater cities form only lithophile trace elements (B, Ba, Sr, U). Soils on the territory of the city alkalized throughout the profile. They are characterized by a high content of carbon and other mineral nutrients. Soils correspond to the allowable category of pollution by heavy metals. Near industrial sites, major roads, garages revealed high concentrations of lead. Based on the geochemical data identified natural and anthropogenic factors of formation of chemical composition of soils. The study of plant herbaceous communities located on the technogenic contaminated territories, including the analysis of species diversity, projective cover of the species, the study of morphometric parameters of plants and their chemical composition. Some characteristics can serve as indicators of heavy metals soil pollution. Based on the studies defined the general concept of environmental monitoring ofPetrozavodsk.

Long-Term Effects of Xerophytic Shrub Haloxylon ammodendron Plantations on Soil Properties and Vegetation Dynamics in Northwest China.

The xerophytic desert shrub Haloxylon ammodendron (C. A. Mey.) Bunge. is distributed naturally in Asian and African deserts, and is widely used for vegetation restoration in the desert regions of Northern China. However, there are limited long-term chrono-sequence studies on the impact of changed soil properties and vegetation dynamics following establishment of this shrub on mobile sand dunes. In Minqin County, Gansu Province, we investigated soil properties and herbaceous vegetation development of 10, 20, 30, 40, 50-year-old H. ammodendron plantations on mobile sand dunes. Soil sampling at two depths (0–5 and 5–20 cm) under the shrubs determined SOC, nutrition and soil physical characteristics. The results showed that: establishment of H. ammodendron had improved soil physio-chemical properties, increased thickness of soil crusts and coverage of biological soil crusts (BSCs), and promoted development of topsoil over an extended period of 5 decades. Soil texture and soil nutrition improved along the chrono-sequence according to three distinct phases: i) an initial fast development from 0 to 10 years, ii) a stabilizing phase from 10 to 30 years followed by iii) a relatively marked restoration development in 40 and 50-year-old plantations. Meanwhile, herbaceous community coverage also markedly increased in 30-year-old plantations. However, both soil and vegetation restoration were very slow due to low annual precipitation in Minqin county compared to other Northern China sand afforestation sites. Canonical Correspondence Analysis results demonstrated that herbaceous plant development was closely associated with changes in soil texture (increased clay and silt percentage) and availability of soil nutrients. Thus our results indicated that selection of the long-lived shrub H. ammodendron is an essential and effective tool in arid desert re-vegetation.

Riparian vegetation of ephemeral streams

Ephemeral streams are abundant in drylands, yet we know little about how their vegetation differs from surrounding terrestrial zones and about their projected response to regional warming and drying. We assessed plant communities at seven ephemeral streams (and terrestrial zones) distributed among three climatic settings in Arizona. Compared to terrestrial zones, riparian zones had similar herbaceous cover but greater woody vegetation volume. They supported more plant species, with several woody taxa restricted to the ephemeral zone (consistent with the idea that herbaceous plants are rain-dependent while riparian trees rely on runoff stored in stream sediments). Their herbaceous communities had high compositional overlap with terrestrial zones and may sustain regional diversity as droughts intensify. Presumably owing to periodic flood disturbance, riparian plant communities had greater evenness than terrestrial zones, many of which were dominated by Eragrostis lehmanniana. Patterns along the climatic gradient suggest that increasing aridity will reduce the number of herbaceous (and total) plant species within riparian zones (110 species per stream in semihumid settings, 88 in semiarid, 48 in arid) and drive compositional shifts from perennials grasses and forbs to annuals. Hotter and drier conditions will drive sharp declines in herbaceous cover, converting riparian savanna to xeroriparian scrubland.

Holm oak decline triggers changes in plant succession and microbial communities, with implications for ecosystem C and N cycling

The occurrence of drought-induced forest die-off events is projected to increase in the future, but we still lack complete understanding of its impact on plant-soil interactions, soil microbial diversity and function. We investigated the effects of holm oak (Quercus ilex) decline (HOD) on soil microbial community and functioning, and how these effects relate to changes in the herbaceous community. We selected 30 holm oak trees with different defoliation degrees (healthy, affected and dead) and analyzed soil samples collected under the canopy (holm oak ecotype) and out of the influence (grassland ecotype) of each tree. HOD increased potential nitrogen (N) mineralization and decreased inorganic N concentrations. These results could be partially explained by changes in the herbaceous composition, an increased herbaceous abundance and changes in soil microbial functional diversity and structure, with HOD favoring bacteria against fungi. Moreover, herbaceous abundance and microbial functional diversity of holm oak and grassland ecotypes converged with HOD. Our results show that HOD triggers a cascade effect on plant understory and soil microbial communities, as well as a plant succession (savannization) process, where understory species colonize the gaps left by dead holm oaks, with important implications for ecosystem C and N budgets.

Trait variation and functional diversity maintenance of understory herbaceous species coexisting along an elevational gradient in Yulong Mountain, Southwest China

Characterizing trait variation across different ecological scales in plant communities has been viewed as a way to gain insights into the mechanisms driving species coexistence. However, little is known about how changes in intraspecific and interspecific traits across sites influence species richness and community assembly, especially in understory herbaceous communities. Here we partitioned the variance of four functional traits (maximum height, leaf thickness, leaf area and specific leaf area) across four nested biological scales: individual, species, plot, and elevation to quantify the scale-dependent distributions of understory herbaceous trait variance. We also integrated the comparison of the trait variance ratios to null models to investigate the effects of different ecological processes on community assembly and functional diversity along a 1200-m elevational gradient in Yulong Mountain. We found interspecific trait variation was the main trait variation component for leaf traits, although intraspecific trait variation ranged from 10% to 28% of total variation. In particular, maximum height exhibited high plasticity, and intraspecific variation accounted for 44% of the total variation. Despite the fact that species composition varied across elevation and species richness decreased dramatically along the elevational gradient, there was little variance at our largest (elevation) scale in leaf traits and functional diversity remained constant along the elevational gradient, indicating that traits responded to smaller scale influences. External filtering was only observed at high elevations. However, strong internal filtering was detected along the entire elevational gradient in understory herbaceous communities, possibly due to competition. Our results provide evidence that species coexistence in understory herbaceous communities might be structured by differential niche-assembled processes. This approach –– integrating different biological scales of trait variation –– may provide a better understanding of the mechanisms involved in the structure of communities.

Post-Grazing Compositional Analysis of an Anthropogenically Altered Northern Fescue Grassland in Northwestern Montana

Abstract Recognizing successional recovery gradients following release from disturbance is important for sustainable land management. To evaluate the recovery and transitions of vegetation post disturbance there needs to be a chronology of community succession. This study in northwestern Montana evaluated the composition of recognized plant communities and proposes successional recovery pathways of the native grassland following release from livestock grazing. Initial surveys were completed 15 years after grazing ended. Inventories of 16 herbaceous vegetation communities indicate that litter depth was the only statistically significant factor related to community composition (P = 0.03) and, importantly, was highly correlated with non-native species canopy cover (r = 0.904). The lack of litter was correlated with the persistence of three climax species (r = 0.736). Comparisons with published grassland community descriptions indicated the intermontane grasslands in this refuge are part of two Northern Fescu...

Co-occurring nonnative woody shrubs have additive and non-additive soil legacies.

To maximize limited conservation funds and prioritize management projects that are likely to succeed, accurate assessment of invasive nonnative species impacts is essential. A common challenge to prioritization is a limited knowledge of the difference between the impacts of a single nonnative species compared to the impacts of nonnative species when they co-occur, and in particular predicting when impacts of co-occurring nonnative species will be non-additive. Understanding non-additivity is important for management decisions because the management of only one co-occurring invader will not necessarily lead to a predictable reduction in the impact or growth of the other nonnative plant. Nonnative plants are frequently associated with changes in soil biotic and abiotic characteristics, which lead to plant-soil interactions that influence the performance of other species grown in those soils. Whether co-occurring nonnative plants alter soil properties additively or non-additively relative to their effects on soils when they grow in monoculture is rarely addressed. We use a greenhouse plant-soil feedback experiment to test for non-additive soil impacts of two common invasive nonnative woody shrubs, Lonicera maackii and Ligustrum sinense, in deciduous forests of the southeastern United States. We measured the performance of each nonnative shrub, a native herbaceous community, and a nonnative woody vine in soils conditioned by each shrub singly or together in polyculture. Soils conditioned by both nonnative shrubs had non-additive impacts on native and nonnative performance. Root mass of the native herbaceous community was 1.5timeslower and the root mass of the nonnative L.sinense was 1.8timeshigher in soils conditioned by both L.maackii and L.sinense than expected based upon growth in soils conditioned by either shrub singly. This result indicates that when these two nonnative shrubs co-occur, their influence on soils disproportionally favors persistence of the nonnative L.sinense relative to this native herbaceous community, and could provide an explanation of why native species abundance is frequently depressed in these communities. Additionally, the difference between native and nonnative performance demonstrates that invasive impact studies focusing on the impact only of single species can be insufficient for determining the impact of co-occurring invasive plant species.

Linkages among canopy tree neighbourhoods, small mammal herbivores and herbaceous communities in temperate forests

AbstractQuestionSmall mammals are important consumers of tree seeds in forests worldwide. Few studies, however, have addressed the impacts of small mammals as consumers of herbaceous species in the forest understorey. Local neighbourhood‐scale variation in canopy tree composition has strong effects on resource availability for understorey plants, but can also influence the distribution, abundance and foraging behaviour of small mammals, primarily through spatial and temporal variation in seed rain. In this study we examine the direct and indirect effects of canopy tree neighbourhoods and herbivory by small mammals on the diversity, abundance and flowering of herbaceous species in a temperate forest.Location and MethodsIn 1994 we established 36 1 m × 2 m fenced small mammal exclosures, paired with similar‐sized control plots, under the major canopy tree species found at Great Mountain Forest, in Norfolk, CT, US.ResultsWhen re‐sampled in 2005, after 10 yrs of small mammal exclusion, the abundance of herbaceous plants had increased inside the exclosures (F = 5.005, df = 1,38, P = 0.031), as did the proportion of plants flowering (t = −2.11, df = 60, P = 0.039). However, species richness and Shannon–Wiener diversity (H′) were similar inside and outside of exclosures. At one site the identity of the canopy tree species did impact species richness (F = 4.494, df = 5,18, P = 0.008), independent of exclosure. Plots under Fraxinus americana (white ash) had the highest species richness (average number of species = 7.5) while the lowest diversity was found in plots under Tsuga canadensis (Eastern hemlock; average number of species = 2.25) and Quercus rubra (northern red oak; average number of species = 1.5).ConclusionsThe results demonstrate that small mammal herbivores can directly affect the abundance and reproduction of herbaceous species, and that local conditions (such as the surrounding canopy tree neighbourhood) can also play direct and indirect roles in the maintenance of the herbaceous layer in temperate deciduous forests.

Trees improve forage quality and abundance in South American subtropical grasslands

Woody plant expansion into rangelands has raised widespread concerns about the potential impacts on livestock production. However, the way in which trees influence the structure, composition and dynamics of herbaceous communities may vary widely depending on local conditions. We studied the effects of trees on the sub-humid grasslands of Uruguay, in southeastern South America, comparing the abundance, diversity and nutrient composition of the herbaceous plants growing under the canopy of isolated trees with those growing at adjacent open places. We analyzed the vegetation patterns at increasing distances from the edge of riparian forests, where tree cover is highest, into the open grasslands. We did not find significant differences between the total biomass of the herbaceous layer growing under and outside tree canopies, but the relative abundance of C3 grasses doubled under trees. Nitrogen content of grasses growing under tree canopies was significantly higher than in adjacent open grasslands, whereas no significant differences were found in P or fiber content. Our results suggest that scattered trees in subtropical grasslands can increase the abundance of high quality forage and contribute to improve the provisioning services of these rangelands.

Higher β-diversity observed for herbs over woody plants is driven by stronger habitat filtering in a tropical understory.

Herbaceous plants are a key component of tropical forests. Previous work indicates that herbs contribute substantially to the species richness of tropical plant communities. However, the processes structuring tropical herb diversity, and how they contrast with woody communities, have been underexplored. Within the understory of a 50-ha forest dynamics plot in central Panama, we compared the diversity, distribution, and abundance of vascular herbaceous plants with woody seedlings (i.e., tree and lianas <1cm DBH and ≥20cm tall). Beta-diversity was calculated for each community using a null model approach. We then assessed the similarity in alpha and beta-diversity among herbs, tree seedlings, and liana seedlings. Strengths of habitat associations were measured using permutational ANOVA among topographic habitat-types. Variance partitioning was then used to quantify the amount of variation in species richness and composition explained by spatial and environmental variables (i.e., topography, soils, and shade) for each growth form. Species richness and diversity were highest for tree seedlings, followed by liana seedlings and then herbs. In contrast, beta-diversity was 16-127% higher for herbs compared to woody seedlings, indicating higher spatial variation in this stratum. We observed no correlation between local richness or compositional uniqueness of herbs and woody seedlings across sites, indicating that different processes control the spatial patterns of woody and herbaceous diversity and composition. Habitat associations were strongest for herbs, as indicated by greater compositional dissimilarity among habitat types. Likewise, environmental variables explained a larger proportion of the variation in species richness and composition for herbs than for woody seedlings (richness = 25%, 14%, 12%; composition = 25%, 9%, 6%, for herbs, trees, and lianas, respectively). These differences between strata did not appear to be due to differences in lifespan alone, based on data from adult trees. Our results point to contrasting assembly mechanisms for herbaceous and woody communities, with herbs showing stronger niche-derived structure. Future research on tropical herbaceous communities is likely to yield new insights into the many processes structuring diverse plant communities.

Scattered trees and livestock grazing as keystones organisms for sustainable use and conservation of Mediterranean dehesas

Mediterranean scattered oak woodlands support relatively high biological diversity, and provide important ecosystem services. However, there is still a lack of knowledge about livestock-tree-grassland relationships, knowledge necessary for effective conservation management in these systems. To address such lacuna, we measured the effects of scattered trees and grazing animals (livestock vs. wild ungulates, mostly deer) on biomass and diversity (and their relationship) of the herbaceous layer (understory) of open holm oak woodland (known as dehesa) in Central Spain, for two years. We located two 1-ha plots within three different grazing management schemes (cattle, sheep and wildlife only). Within each plot, we randomly selected four focal trees from which a subplot was established in two directions and three distances. In each subplot, we measured plant diversity and biomass, along with microclimatic variables across sites. We found rainfall variability affected herbaceous biomass and diversity in the dehesa system, and the effects were nuanced: in a dry year (<300mm annual rainfall) the presence of livestock grazing correlated with higher herbaceous biomass (14%), and in moister year (>600mm annual rainfall) the effect was enhanced, as plots under livestock grazing exhibited even higher herbaceous biomass (42%). In addition, livestock, particularly cattle, generated a more diverse community (52 speciesm−2). Microsites created by trees generated high plant diversity among herbaceous communities, where alpha diversity was higher (20%) in ecotone and inter-tree gaps than under the canopies. In addition, species turnover was higher than 50% in all cases. Biomass was higher (15%) under the canopies only under humid conditions. Legume dry matter was positively related to plant diversity. We concluded that agroforestry management practices such as promoting tree development through silvicultural techniques to create different microsites, and maintaining livestock grazing are needed to preserve these emblematic ecosystems.

Impacts of afforestation on plant diversity, soil properties, and soil organic carbon storage in a semi-arid grassland of northwestern China

Grassland afforestation, occurring in many parts of the world, can modify the nature and transformations of soil organic carbon and associated soil properties, which in turn can affect plant diversity and ecosystem function. Afforestation area has grown rapidly over the last few decades in the semi-arid grasslands of the Qilian Mountains in northwestern China in an effort to restore mountain vegetation. However, ecological consequences of this land use change are poorly known. We investigated the effects of grassland afforestation on plant diversity, soil properties, and soil organic carbon and nitrogen storage at the soil depth of 0–70cm. Our results showed that afforestation decreased percent cover and aboveground biomass, and increased plant diversity of herbaceous community. Afforestation also decreased soil bulk density and pH, and increased soil water content. Generally, afforestation favored an increase in soil organic carbon, total nitrogen, and organic carbon storage, and resulted in a significant increase in total phosphorus in the surface soil (0–5cm), although a slight decrease (P>0.05) was observed in the subsoil. In addition, afforestation significantly increased soil C:N ratio in the upper soil. Results of this study demonstrate the potential for afforestation to increase soil organic carbon and nitrogen storage in semi-arid grasslands of Qilian Mountains. This has important implications for C sequestration in this area.

Evaluating strategies for facilitating native plant establishment in northern Nevada crested wheatgrass seedings

AbstractNon‐native crested wheatgrasses (Agropyron cristatum and A. desertorum) were used historically within the Great Basin for the purpose of competing with weed species and increasing livestock forage. These species continue to be used in some areas, especially after wildfires occurring in low elevation/precipitation, formerly Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis)/herbaceous communities. Seeding native species in these sites is often unsuccessful, and lack of establishment results in invasion and site dominance by exotic annuals. However, crested wheatgrass often forms dense monocultures that interfere competitively with the establishment of desirable native vegetation and do not provide the plant structure and habitat diversity for wildlife species equivalent to native‐dominated sagebrush plant communities. During a 5‐year study, we conducted trials to evaluate chemical and mechanical methods for reducing crested wheatgrass and the effectiveness of seeding native species into these sites after crested wheatgrass suppression. We determined that discing treatments were ineffective in reducing crested wheatgrass cover and even increased crested wheatgrass density in some cases. Glyphosate treatments initially reduced crested wheatgrass cover, but weeds increased in many treated plots and seeded species diminished over time as crested wheatgrass recovered. We concluded that, although increases in native species could possibly be obtained by repeating crested wheatgrass control treatments, reducing crested wheatgrass opens a window for invasion by exotic weed species.

Bee cell trace fossils associations on paleosols from the Santa Cruz Formation: Palaeoenvironmental and palaeobiological implications

Numerous isolated fossil bee cells and other trace fossils are documented from the Santa Cruz Formation (Santa Cruz, Argentina). The trace fossils are described from paleosols of 7 coastal localities. The paleosols are composed of massive to laminated claystone to siltstone or massive to diffuse laminated very fine tuff and reworked tuff. They are poorly developed but include rich trace fossils and root traces assemblages. The isolated bee cells (n=47) are barrel to oval shaped, with one end rounded to flattened and the other flattened. They lack discrete walls and antechambers but have a smooth lining. They are ascribed to Celliforma rosellii (n=28) and to a new ichnospecie, Celliforma argentina (n=19). The new ichnospecies differs from C. rosellii on the shape of the inferior end of the chamber, been the first rounded to flattened and the C. rosellii rounded to pointed, resulting in a final barrel shape in C. argentina and an oval shape in C. rosellii. C. rosellii has an average length and width of 17mm and 9.8mm. C. argentina average length and width are 9.2 and 5.1mm. In some specimens of C. rosellii below the basal mark in the cell, the infill has a strong organic component that has been identified under SEM. This could indicate the exceptional preservation of the fluid deposited by the adult bee for the nutrition of the larva. The trace fossils assemblage shows moderate diversity and abundance. The ichnoassemblage recorded consist in Celliforma rosellii, Celliforma argentina, Palaeophycus tubularis, Planolites beverleyensis, Feoichnus challa, Fictovichnus gobiensis, Taenidium barretti and a variety of root traces. These trace fossils are considered to be part of a Celliforma ichnofacies but with a scarce presence of calcareous components. Considering pedogenic features, compositional aspects and ichnoasemblage a relatively warm, semiarid–subhumid and seasonal climate where herbaceous communities dominated can be established for the middle to upper interval of the Santa Cruz Formation.

Estrutura da vegetação herbácea em paisagens ciliares no sul de Santa Catarina, Brasil

As características estruturais e ecológicas da vegetação herbácea fazem com que ela seja sensível às alterações do ambiente, atuando como indicador da qualidade ambiental. No entanto, o estudo dessa comunidade ainda é incipiente em regiões neotropicais. Este estudo descreve a florística e os aspectos fitossociológicos da vegetação herbácea terrícola na mata ciliar de sete rios, no município de Urussanga, sul do estado de Santa Catarina, além de analisar e quantificar o status do conhecimento científico relacionado às herbáceas terrícolas no Brasil. Foram levantadas 320 unidades amostrais de 4 m², nas quais todos os indivíduos foram identificados e dados relacionados aos parâmetros fitossociológicos foram coletados. A amostragem resultou em 58 táxons, 38 pertencentes às angiospermas e 20 às samambaias, distribuídos em 25 famílias botânicas. Poaceae apresentou maior riqueza, com 11 espécies. Estruturalmente, destacaram-se Goeppertia monophylla (Vell.) Borchs. e S. Suárez, Blechnum brasiliense Desv. e Heliconia farinosa Raddi. A forma de vida mais frequente foi a hemicriptófita reptante. Os resultados revelam uma elevada riqueza de herbáceas terrícolas adaptadas às condições climáticas das matas ciliares, contribuindo para a diversidade da flora regional. Quanto à produção científica, foram encontrados 50 trabalhos indexados nas bases de dados eletrônicas (1990 a 2015), com destaque ao ano de 2011, que teve maior produção científica enfocando as herbáceas terrícolas. Embora com baixo número, a quantidade de indexações tende a crescer, em virtude do avanço da tecnologia de acesso às bases de dados e pela crescente adesão de periódicos em portais de busca.