Herbaceous Stratum Research Articles

Response of understory plant species diversity to plant mixture on the Loess Plateau: A case study of Hippophae rhamnoides

AbstractAfforestation with nature‐based solutions is beneficial for restoring biodiversity. On the Loess Plateau of China, numerous monocultures have been converted to mixed plantations following nature‐based solutions. However, the effect of plant mixture on understory plant species diversity remains largely unknown. Here, we investigated the understory plant species diversity of different Hippophae rhamnoides mixed plantations resulting from nature‐based solutions and assessed the relative importance of associated factors driving their changes. The results showed that the response of understory plant species diversity to plant mixture was nonsignificant, except for Armeniaca sibirica, which significantly reduced the understory plant species diversity. However, mixed plantations had higher variability in plant species diversity and environmental factors among individual plots than monocultures. In mixed plantations, understory plant species diversity was mainly affected by shrub stratum, followed by overstory stratum, soil nutrients, herbaceous stratum, and topography. Specifically, understory plant species diversity was positively associated with stand density and herb biomass but negatively associated with elevation and soil nitrogen. In particular, soil nitrogen also had negative impacts on herb biomass but was beneficial for the growth of trees and shrubs, indicating that trees and shrubs outperformed herbs in exploiting soil nutrients, a consequence of intense interspecific competition. In addition, the impacts of canopy cover and slope aspects on understory plant species diversity were nonsignificant. Overall, in mixed plantations on the Loess Plateau, understory plant species diversity was primarily affected by interspecific competition for preempting soil nitrogen.

Standardising field‐based assessment of invasion degree: A case study in two habitats of Reunion Island

Abstract Biological invasions represent one of the major threats to biodiversity conservation, especially in island ecosystems. Field‐based assessments of the invasion degree are required for managing and monitoring invaded habitats but there is no unifying measure available in the literature. Here, we developed a standardised method for quantifying invasion degree based on four metrics: alien and native species cover, alien species richness, the occurrence frequency of alien species and invasion level, and demonstrated its use in two contrasted habitats of Reunion Island. This rapid survey quantified relative abundance and diversity of alien plant species among three vegetation strata (herbaceous, shrub and tree) in a systematic sampling. In lowland tropical forest, it took 40 person days to survey 150 ha (344 plots), and 52 person days in subalpine vegetation to survey 125 ha (304 plots). Our results showed that the herbaceous stratum was the most invaded in terms of invasion level; more than 45% in lowland tropical forest and almost 55% in subalpine vegetation. Based on cluster analysis and kriging, we mapped three different levels of invasion highlighting potential invasion fronts. We found that it was important to differentiate invasion degree per vegetation strata as mean alien cover was significantly different between strata at each site. This method is suitable for the majority of protected areas where fine‐scale assessment is required to characterise the spatial pattern of plant invasions, monitor invasive species and identify invasion foci to control or populations of emerging species to eradicate.

Plant communities on inselbergs in Burkina Faso

The safeguarding and sustainable management of natural resources, particularly plant resources, requires the implementation of conservation strategies. The study of plant communities is an essential tool for monitoring the development of plant formations. The aim of this study was to identify the plant communities on inselbergs of Burkina Faso in West Africa, to provide a database to supporting the sustainable management of the plant resources withing these fragile ecosystems. Stratified and random sampling was carried out on selected inselbergs in different parts of Burkina Faso along a climatic gradient. In the different phytogeographical sectors, inselbergs consist of granite or sandstone. Plant surveys were conducted using 900 m2 plots for the woody stratum and 100 m2 plots for the herbaceous stratum. An exhaustive list of plant species was compiled and an abundance-dominance coefficient for each species was determined. A DCA, through PCord.6, was used to obtain preliminary groups. Indicator species were determined by a Monte Carlo test with p < 0.05 and calculation of the fidelity index (Phi). Diversity indices through the Shannon index and equitability of Pielou were calculated using Pcord.6 to compare plant communities. A total of 12 plant communities were identified for the inselbergs of Burkina Faso, including 9 communities for savannah and 3 communities for monocotyledonous-mats and ephemeral flush vegetation. The main ecological factors governing the distribution of these inselberg plant communities were found to be were found to be climate, soil depth, soil moisture and altitude. In savannah plant communities, the Terminalia laxiflora and Tephrosia nana communities (unit 6) had the highest number (13) of diagnostic species and the highest fidelity (Phi = 0.97) was for Cleome viscosa species in the Acacia tortilis and Aristida kerstingii communities (unit 1). Diagnostic species numbers vary from 6 to 4 in monocotyledonous-mats and ephemeral flush vegetation and the Dopatrium longidens (Phi = 0.76) and Cyperus podocarpus (Phi = 0.75) have the highest fidelity to unit 3. The Shannon diversity index of deep soil plant communities was highest and significantly different from that of the other savannah communities. Concerning the Piélou equitability index, high values were found in all plant groups, reflecting the absence of species dominance and a balance of the different plant groups.Floristically, Afrotrilepis pilosa infestation of inselbergs is common in West Africa. In Burkina Faso, in addition to Afrotrilepis pilosa, 10 other plant species are found specifically on inselbergs. Given the fragility of the ecosystems in which they live, these inselberg species should be protected.

Combination of organic amendments as a soil recovering strategy at a desertification hotspot in the Brazilian semiarid

AbstractThe use of manure, organic mulch, and legume‐based fertilizers can increase soil fertility in semiarid regions. However, the effects of such practices on soils prone to desertification are unknown. This study aimed to evaluate soil fertility and herbaceous stratum yield on soils amended with different organic inputs in the desertification hotspot of Irauçuba, Ceará state, Brazil. The experiments were performed in two areas with different soils (Planosol and Cambisol), in randomized blocks with a 2 × 2 × 3 + 1 factorial design. The factors consisted of (i) mulch (presence or absence of Copernicia prunifera [carnauba palm] straw), (ii) manure (sheep or cattle), and (iii) legume‐based fertilizer (Mimosa tenuiflora [jurema], Mimosa caesalpiniifolia [sabiá], and Leucaena leucocephala [leucena]), in addition to an untreated control, with three replicates. Soil chemical attributes and herbaceous stratum yield were assessed in the two areas. Positive effects of the combined use of carnauba palm straw, manures, and legume‐based fertilizers on soil fertility were more evident for Planosol than for Cambisol. The combination of sheep manure with sabiá‐based fertilizer in Planosol, and cattle manure and leucena‐based fertilizer in Cambisol increased herbaceous stratum yield. Herbaceous stratum yield in Planosol is more responsive to the input of great amounts of soil nutrients (especially P) and it increases soil organic matter levels, while in Cambisol, herbaceous stratum yield is more associated with the ability of inputs to make nutrients readily available. The use of organic amendments can reverse, in the short‐term, degradation and desertification processes of soils in the Brazilian semiarid region.

Terrestrial insect fauna of the herbaceous stratum of reservoir embankment slopes, Korea

Herbaceous strata with a dominant plant community 50 m in size were selected from 10 reservoir embankment areas in Shinan-gun, a southwestern island region of South Korea. Terrestrial insects were sampled 100 times with quantitative sweep sampling to investigate the insect fauna and their association with flora. The survey areas were mainly dominated either by Phragmites japonica or Miscanthus sinensis plant species. A total of 1,948 individual insects representing 173 species from 64 families within 9 orders were collected. The number of species was the highest at Jaeundo while the Shannon-Wiener diversity index was the highest at Saokdo. Similarity analysis showed that the insect species composition tended to be similar among survey sites with plant communities comprising the same dominant plant species. Species diversity was the highest in April while the number of individual insects was the highest in September. Petaphora maritima and Ochetellus glaber were the dominant and subdominant insect species, with a high frequency of occurrence at these sites. The results of this study could be applied towards biodiversity conservation and monitoring of reservoir embankment areas in the future.

Inselbergs: potential conservation areas for plant diversity in the face of anthropization

Faced with the loss of biodiversity, particularly plant diversity, due to anthropogenic pressure, particular ecosystems such as inselbergs can constitute refuge areas. The objective of this study is to determine the conservation potential of plant biodiversity on inselbergs in Burkina Faso. A comparative study was carried out between inselberg’s vegetation and the surrounding plains vegetation. In each of these vegetation types, stratified and random sampling was adopted and data were collected in plots of 900 m² for the woody stratum and 100 m² for the herbaceous stratum. The specific diversity was evaluated through the effective numbers of Hill of order Q = 0; 1; 2. The Hill index does not vary between inselbergs and plains and thus reflects a strong similarity in floristic diversity between the two ecosystems. Sorensen’s similarity coefficient also shows a similarity in terms of floristic composition between inselbergs and surrounding plains. In inselbergs, relict species that have disappeared from the surrounding plains of some phytogeographic sectors occur. The flora of inselbergs is also characterised by indicative species of anthropized ecosystem absence. However, these species are present on the surrounding plains. Indeed, the flora of inselbergs is characterised by 11 endemic species. Inselberg’s vegetation is characterised by unique plant communities such as rock pools and Afrotrilepis pilosa mats. The exploitation and mortality rates of woody plants are significantly higher on the surrounding plains than on the inselbergs. The flora and vegetation of inselbergs show the absence of indicator species of disturbed ecosystems. They present endemic and relict species and stable woody stands. Due to the steep slope, lack of suitable soil for agriculture and sacred status of someones, the inselbergs constitute a refuge for plant species and thus contribute to the conservation of biodiversity like the protected areas.

Structure and Phenology of Herbaceous Stratum in the Sahelian Rangelands of Senegal

This study describes the structure and phenology of Sahelian rangelands during the rainy season. It was undertaken on a grazed plot and a fenced plot. Measurements were taken every 10 days over two rainy seasons between July and October 2018 and between August and October 2019. The measurements included the phenological stage, the vegetative and flowering height, the coverage, and the phytomass. The results showed that phytomass did not systematically differ between grazed and fenced plots. Flowering started as early as mid-July, but most of the plants flowered in early October. Flowering and fruiting occurred earlier (based on the number of days after the first rain) in the late rainy season (2019) than in the early one (2018). These stages reached their peak in October; senescence began in October. Vegetative height, reproductive height, and coverage were similar between the two years. Height peaks were similar, but they were reached earlier (based on the number of days after the first rain) in the late rainy season than in the early one. Coverage peaks were similar (59.8% in the early rainy season vs. 65.8% in the late one). Vegetative height (around 30 cm), reproductive height (around 36 cm), and coverage (around 60%) reached their maximum in October, but reproductive height was greater than vegetative height. These parameters were lower at the grazed site compared to the fenced site, and flowering started earlier at the grazed site. The pasture had a negative impact on coverage, height, and early flowering. Structure and phenology were more sensitive than to changes in rainfall between years. Phenology results will help determine the best time to harvest the phytomass (phytomass stock), as the nutritional quality of the forage is known to decrease after fruiting.

Diversity and relative abundance of rodent species under three habitat conditions in the Altiplano Potosino Oeste, Mexico

Objective: To evaluate the diversity and abundance of rodent species, as well as vegetation cover, under three habitat conditions in the Altiplano Potosino Oeste. Design/Methodology/Approach: The work was carried out in eight sites with good (3), regular (2), and poor (3) vegetation cover conditions. Frequency, basal, and aerial cover data were collected in three plot sizes to obtain the results for the three types of vegetation: arborescent stratum (20×20 m), shrubs (3 plots of 5×5 m), and herbaceous stratum (2 plots of 1×1m). In order to collect the rodent data, three sampling nets with 100 Sherman traps were used. Rodent species diversity was determined using the Shannon-Whinner index (SWI), while abundance was obtained using the Relative Density Index (RDI). Differences were determined using ANOVA. Results: Grass cover decreased depending on the condition; however, this was not the case of the shrub cover. The overall diversity of rodent species was 21 (16 in fair, 15 in good, and 14 in poor condition). The total SWI and RDI decreased depending on the condition. Dipodomys ornatus, D. merriami, and Chaetodipus nelsoni were the most abundant and most widespread species. Study Limitations/Implications: The study was conducted during the most restrictive season and under drought conditions. This situation impacted cattle, but not rodents. However, although their plasticity maintained relatively stable RDI values, the indices decreased depending on the condition. Findings/Conclusions: Despite their habitat conditions, the rodents found in the area are more diverse and abundant than those reported in reference works. Therefore, further studies about this subject should be carried out using rodents as bioindicators

Composición florística y funcional del pastizal natural del centro de la Argentina: Efecto del pastoreo bovino y el fuego

The state and conservation of the natural resources involved in production systems is of global concern. In Argentina, the expansion of the agricultural frontier from the Humid Pampa to the west has intensified livestock activity in semi-arid areas, decreasing the probability of finding sites that are not severely anthropized for productive purposes. The objectives of this work were to characterize the floristic and functional composition of the herbaceous stratum of caldén forests in a site excluded from domestic grazing in the last 50 years and to compare it with two other situations: one, with a winter fire event and subsequent exclusion of ca

Pollen meta-barcoding reveals different community structures of foraged plants by honeybees (Apis mellifera L.) along space-time gradient in Japan

The availability of pollen in urban-rural landscapes is an essential factor that influences the population dynamics of insect pollinators. The amount and diversity of pollen play a pivotal role in the foraging ecology of pollinators for their growth and health, but investigations on the spatio-temporal patterns of foraged plants remain rare, especially in cities as neo - ecosystems. Here, we explored the temporal foraging habits of a highly pollinator (Apis mellifera L.) in Tokyo, including different landscape classes from rural to urban areas. Mixed-pollen samples in each month and each location (N = 17) were analysed using DNA meta-barcoding to identify plants visited by honeybees. The results showed that the landscape class (rural, suburban and urban areas) explains spatial variations in pollen source-plant composition foraged by honeybees, but not in taxa richness. Furthermore, pollen diversity and pollen source-plant composition showed a strong seasonal dependence. A higher plant richness and foraged woody taxa was found to occur in spring, which was mainly dominated by the genera Prunus and Acer. In summer and autumn, the genera Trifolium and Plantago of the herbaceous stratum were the most visited plants. The Fabaceae, Rosaceae, Brassicaceae, Plantaginaceae, and Onagraceae plant families were the most frequently observed in all combined samples. The present study contributes to a deeper understanding of the foraging ecology of A. mellifera colonies across urban-rural gradient surrounding mega-cities such as Tokyo.

RESPONSE OF TAXONOMIC AND FUNCTIONAL BENTHIC MACROFAUNA RICHNESS TO LAND USE AND LAND COVER AT BRAZILIAN RESERVOIRS DURING EXTREME DROUGHT

Introduction: Reservoirs are artificial aquatic ecosystems created by damming rivers, and are influenced by different sorts of impacts. Anthropic land use and occupation are one of the main causes of the loss of environmental quality and biological diversity in aquatic ecosystems. The objective of this work was to evaluate the effects of land use and occupation on the taxonomic and functional richness of benthic macroinvertebrates in reservoirs in the Brazilian semiarid region during a period of extreme drought. Material and methods: The study was conducted in six reservoirs located in the semiarid region from Brazilian Northeast (Paraíba and Rio Grande do Norte states): Sabugí, Passagem das Traíras, Cruzeta, Cordeiro, Sumé and Poções. The collections of benthic macrofauna, physical and chemical variables of water and the mapping of land use and occupation were performed for the years 2014 and 2019, in June and September. The sampling period was characterized as the most severe drought in the last 50 years in this study area. The land use and occupation were verified through the semi-supervised classification method of images captured by the Landsat 8 satellite, within 100 meters of the reservoir margin. The diversity of benthic macrofauna was analyzed through the taxonomic richness and functional richness, according to five functional characteristics: feeding trophic groups, breathing mode, voltinism, body size and body protection. To check for significant differences in physical and chemical water variables and taxonomic and functional richness among land use and land cover categories we performed PERMANOVA test. Results and Discussion: Seven land use and land cover categories were found in the reservoirs studied in the years 2014 and 2019, these are: water, agriculture, pasture, exposed soil, human occupation, open vegetation (native and exotic species of small/medium size with continuous spacing) and tree/shrub vegetation (native and exotic species of medium/large size with associated herbaceous stratum and predominance of semi-continuous dorsel). In all reservoirs the prevalent-use was pasture. Physical and chemical variables of water varied significantly among land use and land cover types, they were soluble reactive phosphate (p=0.02), total phosphorus (p=0.002) and water volume (p=0.01). The highest concentrations of total phosphorus were associated with predominant human occupation and soluble reactive phosphate with agriculture. The highest percentage of water volume was associated with a predominant use of tree/shrub vegetation. In reservoirs of semiarid regions with low connectivity due to intermittent rivers and extreme drought periods, adjacent anthropic activities such as agriculture, pasture and human occupation are the main external sources of nutrients. The taxonomic and functional richness of benthic macrofauna was higher in areas of open vegetation, however, it did not vary significantly between land use and land cover categories. Conclusions: Our results show that the effects of anthropic use and occupation in reservoirs associated with water scarcity lead to the homogenization of the macrobenthic community, which can generate negative consequences in processes sustained by the community.

First record of phytolith assemblages from the Salto Ander Egg Formation (Late Pleistocene). Palaeoenvironment inferences in the Last Interglacial Stage in southwestern Mesopotamia (Entre Ríos, Argentina)

This contribution aims to describe the first palaeobotanical record of the Late Pleistocene in the Salto Ander Egg Formation (SAEF) through the analysis of phytolith assemblages. The microremains association allowed us to characterise the palaeoenvironmental conditions for these deposits and to complete the palaeobotanical record for the stratigraphic sequence of the Late Pleistocene in southwestern Entre Ríos province, Argentina. The Salto Ander Egg Formation is composed of fluvial deposits with a well-defined floodplain and channel facies dated at ages ranging from 120 to 60 ky. The phytolith content of the unit was analysed along two stratigraphic sections in outcrops exposed on the cliffs of the fluvial valleys located in the drainage basin of La Ensenada creek. The vegetation composition was interpreted principally from the proportions of very frequent and frequent morphotypes in the phytolith assemblages and was grouped in plant functional group affinities: “non-GSSCPs” (diagnostic grass phytoliths); “GSSCPs” (grass silica short cell phytoliths); “Woody dicots” and “Palms”. The phytolith assemblages describe a palaeoflora composed of a continuous herbaceous stratum of C3/C4 grasses, although C3 might have been more significant accompanied by isolated trees and palms in an open savanna physiognomy, probably with a temperate/warm climate with low rainfall and average to high temperatures.

From the ground up: Patterns and perceptions of herbaceous diversity in organic coffee agroecosystems

Abstract Smallholder farms that transition to organic and biodiverse production are increasingly recognized as strongholds of agrobiodiversity, with emerging work identifying important outcomes such as enhancing crop portfolios, mitigating extreme climate events and contributing to farmer well‐being. Yet the emergent herbaceous communities in these organic systems remain understudied, with the functional diversity and management of this stratum relatively unknown. This study identifies the taxonomic and functional diversity of the herbaceous community in organic coffee agroforestry systems, and describes the extent of this diversity with farm, and farmer, attributes. We measured leaf‐level functional traits (e.g. specific leaf area) of the herbaceous community to derive functional diversity indices and collected localized environmental conditions on 15 organic coffee farms in Central Valley, Costa Rica. We also conducted semi‐structured interviews with nine farmers to construct mental models on herbaceous community management using a cognitive mapping approach. In total, 38 species from 20 taxonomic families were present in these organic coffee systems. The herbaceous communities were functionally diverse; however, functional evenness increased with canopy openness, suggesting that farms adopting agroforestry tend to have a more functionally diverse herbaceous stratum. Farmer perception of plant traits in the herbaceous community was differentiated into competitive (weeds) or neutral/positive effects. These perceptions aligned with well‐established functional trait trade‐offs. The mental models representing farmer decision‐making processes were highly variable, with a nearly 30% increase in cognitive map density from the simplest map to the most complex; this complexity in mental models was a key explanatory variable in the level of functional diversity of the herbaceous community. Organic management practices that support agroforestry practices also, in turn, promote a functionally diverse herbaceous stratum. We show that functional trait syndromes in these herbaceous communities in agroforestry systems are linked with farmer perceptions of traits, and that highly interconnected farm decision‐making is related to greater functional diversity in the herbaceous community. Understanding pathways of farmer decision‐making on managing this herbaceous community can appropriately situate on‐farm practice and policy for the transition to organic production, and inform emerging agri‐environmental programs.

Análisis de la diversidad funcional del estrato herbáceo en un ecosistema de dehesa a partir de datos hiperespectrales "in situ"

El presente trabajo aborda la estimación de la diversidad funcional (FD) del estrato herbáceo en un ecosistema de dehesa mediante datos hiperespectrales obtenidos con un espectro-radiómetro portátil ASD FieldSpec® 3 (Analytical Spectral Devices Inc., Boulder, CO, EE. UU.). Los datos ópticos se correlacionaron con variables biofísicas (área foliar específica (SLA), biomasa aérea (AGB), índice de área foliar (LAI) y contenido de nitrógeno (N%)) e índices de diversidad tradicionales como Shannon y Evenness y otros relacionados con la diversidad funcional como el índice multidimensional de dispersión funcional (FDis) usando como variables predictoras: a) índices de vegetación (VIs) y métodos de regresión simple, y b) bandas espectrales y Partial Least Squares Regression (PLSR). Las correlaciones, especialmente de las variables biofísicas relacionadas con FDis, mejoraron sustancialmente al utilizar información hiperespectral (R2 &gt;0.6, rRMSE &lt;0.1) lo que confirma el interés de la dimensión espectral para estimar la diversidad funcional de un ecosistema complejo como es el caso de los pastizales semi-áridos.

Sweep Sampling Comparison of Terrestrial Insect Communities Associated with Herbaceous Stratum in the Riparian Zone of the Miho River, Korea.

Simple SummaryInsect pests and their natural enemies can harbor in riparian zones. To determine the impact of insect communities on agriculture and ecology, we must quantitatively assess insect populations in riparian areas. To identify the appropriate methodology for effective insect sampling in riparian areas, we assessed sweep sampling within three plant communities using different numbers of subsampling units (50 sweeps carried out twice, or 10 sweeps over 10 times) over two years. The results reveal that effective insect sampling varies between different plant communities and insect orders. The similarities between terrestrial insect communities in the same plant community were relatively high, even in different years. The optimum sampling size to obtain approximately 80% of the total species was estimated for each survey site. Our results lay the foundations for providing techniques to assess insect populations within riparian areas to predict and prevent herbivorous insect pest invasions in the future.To investigate insect and plant community relationships in riparian zones, terrestrial insect communities were compared in plant communities in the riparian zone of the Miho River, Korea. The sweep netting method was used to sample insects in 50 m transects in three herbaceous plant communities. In 2020, each plant community—Chenopodium album, Beckmannia syzigachne, and Artemisia indica—was swept 100 times (50 sweeps × 2). In 2021, two communities had an additional 100 sweeps collected using 10 subsamples of 10 sweeps (excluding C. album communities). The surveyed dominant species or subdominant species of the insect community in each site preyed on the dominant plant species at the site. The Bray–Curtis similarity was significantly higher than the Sørensen similarity when comparing datasets across different years for the same plant species community. The predicted optimum sampling size to obtain approximately 80% of the total species estimated to be at each survey site, for effective quantitative collection of terrestrial insect herbivores in each plant community, was examined. Fifty sweeps were required for the A. indica community and 100 sweeps were required for the B. syzigachne community. The results of this study provide important data for riparian biodiversity conservation and future pest monitoring.

NATIVE CAATINGA SPECIES FOR THE RECOVERY OF DEGRADED AREAS IN THE BRAZILIAN SEMIARID REGION

ABSTRACT This study aimed to prospect, among the species that grow spontaneously in compacted landfills, native Caatinga plants with potential for ground cover in extremely impacted areas, with exposed soil. Initially, a general floristic survey was carried out in the four study areas. To prospect the species, data referring to the richness, coverage, and densification of plants in the herbaceous stratum were collected in each study area, using the method of plots. The selection was based on species-specific characteristics: origin, plant habit, life cycle, propagation, dispersion syndrome, coverage, densification, and allelopathic effect. The general floristic inventory revealed the presence of 73 species belonging to 63 genera and 26 botanical families. In the survey of the coverage and densification of the herbaceous stratum, 33 species belonging to 32 genera and 16 families were found, being the most representative: Fabaceae (5), Malvaceae (5), and Poaceae (5). As for the origin, 26 are native, one is naturalized, and six are exotic, of which 66.6% are in the Poaceae family. Moreover, most of these species are herbs, with an annual life cycle, dissemination through seeds, and present autochoric dispersion. The coverage and densification of these species ranged from 0.44% to 9.5% of the area and 1 to 4.44 of individuals/m2, respectively. The species Senna uniflora, Rhaphiodon echinus, Sida galheirensis, Mesosphaerum suaveolens, Hexasepalum teres, Waltheria rotundifolia, Trianthema portulacastrum, and Herissantia crispa showed potential for use in recovery plans for degraded areas based on the results presented by each of them in the parameters analyzed, especially in coverage, densification, dispersion syndrome, and life cycle.

Novidades do estrato herbáceo em uma região chave para a conservação da Amazônia Meridional

Abstract The contribution of the herbaceous stratum to tropical plant diversity is considerable, however this component remains undersampled. We investigated floristic, structural, ecological and conservation issues concerning the herbaceous component of a seasonal deciduous forest associated with granitic rock outcrops in the Cristalino Region, a key area for biodiversity conservation in the Brazilian Amazon. We installed a permanent plot of 1 ha, allocating 10 transect-lines of 20 m each. We identified the sampled individuals, measured height and projection, and verified cover and frequency per species, genera and family. We recorded 86 species, 62 genera and 25 families, with Orchidaceae being the family with the highest species richness. Among the 26 new species added to Cristalino Flora, we included Philodendron deflexum Poepp. ex Schott and Griffinia nocturna Ravenna, the latter ‘Critically Endangered’. Furthermore, the occurrence of G. nocturna in an Amazonian forest matrix is a novelty in this study. The estimate of species diversity according to Shannon-Wiener (H’) was 2.43 nats.ind.-1 (equivalent to 11.37 ± 0.90 IC95% equally common species), and according to Simpson (1/D), 6.82 (± 0.648 IC95%). The rarefaction and extrapolation curves for the diversity estimates tended to stabilize. Although the vegetation on rock outcrops usually presents a high number of endemic species, this pattern was not found in our study area, which can be explained by its continuous occurrence in the forest matrix. The understory of our study area consists in a mixture of floras, being composed mainly of species from the Amazon and/or Cerrado biomes. In view of the current anthropic pressure faced by the southern Amazon, we reinforce the importance of carrying out inventories of its herbaceous communities, since the risk of species loss is even more alarming when considering present undersampling of this component.

Macaronesia Acts as a Museum of Genetic Diversity of Relict Ferns: The Case of Diplazium caudatum (Athyriaceae).

Macaronesia has been considered a refuge region of the formerly widespread subtropical lauroid flora that lived in Southern Europe during the Tertiary. The study of relict angiosperms has shown that Macaronesian relict taxa preserve genetic variation and revealed general patterns of colonization and dispersal. However, information on the conservation of genetic diversity and range dynamics rapidly diminishes when referring to pteridophytes, despite their dominance of the herbaceous stratum in the European tropical palaeoflora. Here we aim to elucidate the pattern of genetic diversity and phylogeography of Diplazium caudatum, a hypothesized species of the Tertiary Palaeotropical flora and currently with its populations restricted across Macaronesia and disjunctly in the Sierras de Algeciras (Andalusia, southern Iberian Peninsula). We analysed 12 populations across the species range using eight microsatellite loci, sequences of a region of plastid DNA, and carry out species-distribution modelling analyses. Our dating results confirm the Tertiary origin of this species. The Macaronesian archipelagos served as a refuge during at least the Quaternary glacial cycles, where populations of D. caudatum preserved higher levels of genetic variation than mainland populations. Our data suggest the disappearance of the species in the continent and the subsequent recolonization from Macaronesia. The results of the AMOVA analysis and the indices of clonal diversity and linkage disequilibrium suggest that D. caudatum is a species in which inter-gametophytic outcrossing predominates, and that in the Andalusian populations there was a shift in mating system toward increased inbreeding and/or clonality. The model that best explains the genetic diversity distribution pattern observed in Macaronesia is, the initial and recurrent colonization between islands and archipelagos and the relatively recent diversification of restricted area lineages, probably due to the decrease of favorable habitats and competition with lineages previously established. This study extends to ferns the concept of Macaronesia archipelagos as refugia for genetic variation.

Patterns of Ant Diversity in the Natural Grasslands of Southern Brazil.

In the south of Brazil, grasslands are naturally widespread over two different biomes, the Pampa in the southernmost region and within the Atlantic Forest in the northern portions. The natural grasslands of the state of Paraná comprise a very particular physiognomy composed of two distinct formations: the Campos Gerais and the grasslands of the southwest. The first is located in the edge of the second plateau of Paraná state, comprising a great diversity of environments. The grasslands of the southwest are more homogeneous, with a continuous herbaceous stratum dominating the landscape. In this context, the aim of this study was to evaluate the patterns of species richness and composition of ants, an ecologically prominent group, along the natural grasslands of Paraná. We also intended to compare the faunal similarity between the two different grassland formations. For that, four different Conservation Unities were sampled along a latitudinal gradient. A remarkable total of 245 ant species was recorded, and the results indicate that species richness decreases as latitude increases along the grasslands of Paraná. There were clear differences in species composition between these two grasslands formations, given the significative number of endemic species in each of these two grassland formations. Ten species were recorded for the first time in the state of Paraná, of which three also for the first time in the Southern Region of Brazil. Overall, our study contributes to a better understanding about the diversity and composition of ant communities in subtropical grasslands.

Continuous presence of proto-cereals in Anatolia since 2.3\xa0Ma, and their possible co-evolution with large herbivores and hominins

Cereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture. Here we demonstrate that cereals may have a significantly longer and more diverse lineage, based on the study of a 0–2.3 Ma, 601 m long sedimentary core from Lake Acıgöl (South-West Anatolia). Pollen characteristic of cereals is abundant throughout the sedimentary sequence. The presence of large lakes within this arid bioclimatic zone led to the concentration of large herbivore herds, as indicated by the continuous occurrence of coprophilous fungi spores in the record. Our hypothesis is that the effects of overgrazing on soils and herbaceous stratum, during this long period, led to genetic modifications of the Poaceae taxa and to the appearance of proto-cereals. The simultaneous presence of hominins is attested as early as about 1.4 Ma in the lake vicinity, and 1.8 Ma in Georgia and Levant. These ancient hominins probably benefited from the availability of these proto-cereals, rich in nutrients, as well as various other edible plants, opening the way, in this region of the Middle East, to a process of domestication, which reached its full development during the Neolithic.