Leaf Litter Samples Research Articles

Value of Riparian Vegetation Remnants for Leaf-Litter Ants (Hymenoptera: Formicidae) in a Human-Dominated Landscape in Central Veracruz, Mexico.

Riparian remnants are linear strips of vegetation immediately adjacent to rivers that may act as refuges for biodiversity, depending on their habitat quality. In this study, we evaluated the role of riparian remnants in contributing to the diversity of leaf-litter ants by determining the relationship between ant diversity and several riparian habitat characteristics within a human-dominated landscape in Veracruz, Mexico. Sampling was carried out in 2012 during both dry and rainy seasons at 12 transects 100 m in length, where 10 leaf-litter samples were collected along each transect and processed with Berlese-Tullgren funnels and Winkler sacks. A total of 8,684 individuals belonging to 53 species, 22 genera, and seven subfamilies were collected. The observed mean alpha diversity accounted for 34.4% of the total species recorded and beta diversity for 65.6%. Species richness and composition were significantly related to litter-layer depth and soil compaction, which could limit the distribution of ant species depending on their nesting, feeding, and foraging habits. Riparian remnants can contribute toward the conservation of ant assemblages and likely other invertebrate communities that are threatened by anthropogenic pressures. In human-dominated landscapes where remnants of riparian vegetation give refuge to a diverse array of myrmecofauna, the protection of the few remaining and well-preserved riparian sites is essential for the long-term maintenance of biodiversity.

Solid Fuel Generation from Urban Leaf Litter in Mixture with Grass Cuttings: Chemical Composition, Energetic Characteristics, and Impact of Preprocessing

Urban biomass from green areas is a potential resource for bioenergy recovery, which is widely unused. Different types of organic material (e.g., grass, leaf litter) usually occur in mixtures due to common collecting practice. Forty samples of grass, leaf litter (genera: Acer, Quercus, Tilia), and mixtures of both, containing one third grass or leaf litter, were investigated to evaluate the effect of the “Integrated Generation of Solid Fuel and Biogas from Biomass” (IFBB) on material and energy fluxes as well as relevant characteristics of resulting energy carriers. IFBB divides biomass into a fiber-rich press cake and a highly digestible press fluid by mashing with subsequent pressing. Ensiling of samples was successful with pH values ranging from 4.2 in grass to 4.8 in pure Tilia samples. Concentration of most minerals with exception of Ca and Mg were higher in grass than in leaf litter silage. The IFBB treatment reduced the element concentration in the press cake independently from the substrate. Linear regression models revealed high influence of the initial concentration in silage on the concentration in the press cake. The lower heating value of the press cake was nearly constant (19 MJ kg−1 DMash free) independent from mixture. Methane yields from press fluid digestion ranged from 172 (mean of leaf litter samples) to 325 lN kg−1 VS (mixture of 33 % leaf litter—66 % grass). For an evaluation of the economic and ecological potential, models of the spatial and temporal occurrence of these biomasses need to be established.

Ecology and diversity of leaf litter fungi during early-stage decomposition in a seasonally dry tropical forest

Leaf litter samples of 12 dicotyledonous tree species (belonging to eight families) growing in a dry tropical forest and in early stages of decomposition were studied for the presence of litter fungi. Equal-sized segments of the leaves incubated in moist chambers were observed every day for 30 d for the presence of fungi. Invariably, the fungal assemblage on the litter of each tree species was dominated by a given fungal species. The diversity of fungi present in the litter varied with the tree species although many species of fungi occurred in the litter of all 12 species. A Pestalotiopsis species dominated the litter fungal assemblage of five trees and was common in the litter of all tree species. The present study and earlier studies from our lab indicate that fungi have evolved traits such as thermotolerant spores, ability to utilize toxic furaldehydes, ability to produce cell wall destructuring enzymes and an endophyte-litter fungus life style to survive and establish themselves in fire-prone forests such as the one studied here. This study shows that in the dry tropical forest, the leaf litter fungal assemblage is governed more by the environment than by the plant species.

The Next New Species ofNotophthiracarusRamsay, 1966 (Acari, Oribatida, Phthiracaroidea) from Madagascar

Five new species of the genus Notophthiracarus are described, identified and figured from sifted soil and leaf litter samples from different parts of Madagascar: N. liratus sp. n., N. lineatus sp. n., N. micidus sp. n., N. obliquus sp. n., and N. quasisimilis sp. n. Comparisons with the most closely related species of the genus are also presented.

Field estimates of detectability and site occupancy show that northern Italy forest molluscs are spatially rare and poorly detectable

Estimations of site occupancy of species and their vital rates, and of species richness of a community, are biased if detection probability is not taken into account. Models that allow the joint estimation of occupancy and detectability were used in a land mollusc survey in six forest habitats in northern Italy, allowing estimations for 55 species of land snails. Most species were poorly detectable (p ≤ 0.3). Detectability varied among habitats and collecting techniques. Taking into account detectability, occupancy estimations may be from 15 to 85% larger than the naïve occupancy values computed by dividing the number of stations at which the species was detected by the total number of stations (0.13–0.42 in absolute terms), significantly altering our understanding of species rarity. In several habitats the share of spatially rare species was remarkably high, above 30%, with peaks above 60%; at the regional scale 62.7% for visual sampling and 46.7% for leaf litter and soil sampling. The sampling effort to monitor occupancy for the numerous uncommon to rare species is well above what would be satisfactory in terms of saturation of species inventory. Visual search gave higher estimates of detectability for species above 1 cm in size, while leaf litter and soil sorting gave higher estimates for species below 1 cm. Consideration of fresh empty shells along with living individuals allowed us to improve the estimates, but when interpreting results the bias induced by taphonomic processes has to be considered. When detection probabilities are unknown, an estimate of their order of magnitude may be obtained by relative abundances, while shell size does not correlate significantly with detectability.

Organic matter carbon, nitrogen, and phosphorous from a single persulfate digestion

AbstractEcological stoichiometry requires accurate measurement of carbon : nitrogen : phosphorus ratios in organic matter. Currently, carbon : nitrogen : phosphorus ratios are typically determined by analyzing one sample for carbon : nitrogen and another sample for percent phosphorus. Not only does this approach require multiple samples and accurate sample weights, but it also obscures natural variability. We developed a method which allows us to obtain carbon : nitrogen : phosphorus ratios from a single, small sample of organic matter. The analysis consists of a single persulfate digestion in sealed vials that converts the organic carbon (C), nitrogen (N), and phosphorus (P) to carbon dioxide gas (CO2), nitrate ion, and phosphate ion. The combination of 3% persulfate in 0.15 M NaOH provides a digestion that is initially alkaline but becomes acidic after about 30 min. In the final acidic solution, CO2 is driven into the vial headspace and is measured on a gas chromatograph‐mass spectrometer. Nitrate and phosphate are measured on an ion chromatograph and by using standard colorimetric methods, respectively. We assessed the method by evaluating recovery of C, N, and P from chemical standards and by comparing values obtained with this method to those obtained by current, conventional methods. We used cultured algae and pond seston on filters, leaf litter, and zooplankton samples for the method comparisons. The method is precise at low mass; we were able to confidently measure C : N : P ratios on individual Daphnia magna. The method showed high recovery for standards and produced C : N : P ratio values similar to those found by other analytical approaches and to values in the literature.

Ecological relations between mangrove leaf litter and the spatial distribution of the gastropod Melampus coffeus in a fringe mangrove forest

Leaf litter represents a food source to many organisms that may directly contribute to organic matter decomposition. In addition, the physical presence of these vegetal detritus contributes for the modification of some environmental areas and produce microhabitats that may act as a refuge against predators and desiccation for many animals. The pulmonate gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) is a very common specie in Atlantic Coast mangrove forests and feeds on fallen mangrove leaves. It was hypothesized that the spatial distribution of Melampus coffeus is directly affected by mangrove leaf litter biomass deposition. Thus, this research aimed at evaluating the spatial distribution of these gastropods in relation to the biomass of mangrove leaf litter through a twelve-month period. The study area was established in the middle estuary of Pacoti River, state of Ceará, Brazil where two adjacent zones with different topographic profiles were determined. Samples of Melampus coffeus and leaf litter were collected monthly, throughout a year, from the mangrove ground surface. The results indicated that the presence of twigs in mangrove litter favor the occupation by smaller individuals of M. coffeus, probably because smaller individuals are more susceptible to predator attacks and desiccation than larger ones, and twigs and branches may provide a safe microhabitat.

Polylobatispora setulosa, a new freshwater hyphomycete from Ilhabela, Sao Paulo state, Brazil

Polylobatispora setulosa sp. nov. is described and illustrated from submerged mixed leaf litter samples collected at streams in Ilhabela, Sao Paulo state, Brazil. The fungus is distinct in having setulae at the tip of the conidial lobes. Acumispora verruculosa, isolated from identical substrate and characterized by the presence of fusiform, acuminate, rostrate, verrucose, 2-septate, hyaline to greenish conidia, is recorded for the third time from the Americas. They are compared with morphologically similar species and identification keys are provided.

Diversity of filamentous fungi in leaf litter and aerial litter in semi-deciduous forest, Bahia, Brazil

The fungi have wide distribution in ecosystems and can be found colonizing various substrates, where they act as efficient decomposers, participating in cycling of nutrients. The present study aimed to assess the diversity, richness and composition of filamentous fungi in leaf litter and aerial litter in a semi-deciduous forest in the Chapada Diamantina, Bahia, Brazil. Samples of leaf litter and aerial litter were collected monthly from October/2009 to September/2010 in eight installments in the studied area. Those samples were washed, placed in moist chambers and incubated. 47 taxa were identified, 37 in leaf litter and 35 in aerial litter, with 25 species common to both. A similarity of 69 % according to Sorensen index. The similarity was considered low when the sample points were compared to the same litter. Most fungi showed sporadic intervals.

Observations of Adelomyrmex (Hymenoptera: Formicidae) reproductive biology facilitated by digital field microscopy and DNA barcoding

AbstractMany Neotropical species whose range is restricted to tropical montane cloud forests (TMCF) are in danger of local or total extinction due to warming and drying as air warmed by climate change ascends these mountains. While the species richness of many arthropod higher taxa declines at high elevations, those species that do reside in TMCF are often highly specialised and endemic, rendering their natural history especially interesting. However, we know little about these TMCF arthropods. One genus of ants, Adelomyrmex Emery, 1897 (Hymenoptera: Formicidae), is characteristic of many TMCFs in Central America, and exemplifies this pattern. While workers of this genus are very common in leaf litter samples, winged males and winged queens have been unknown and nests have never been observed for most species. Here we report how a combination of affordable digital field microscopes and DNA barcoding has allowed nest discovery and documentation and linked male and worker Adelomyrmex. Based on this work, we have now learned that male Adelomyrmex can be quite abundant locally.

Study on diveresity of spider fauna in Jnana Sahyadri campus, Shimoga, Karnataka

A study on diversity of spiders in different locations of Jnana Sahyadri campus, Kuvempu University, Shimoga, Karnataka was conducted using beating, Active searching, visual observation and net sweeping and leaf litter sampling techniques. Survey and sampling was conducted during January to April 2013. A total of 316 individuals of 17 species belonging to 10 families were recorded. The Salticidae was the most dominant family having the highest number of species recorded (6), followed by the family Oxyopidae and Pholcidae (2) and in families Hersiliidae, Lycosidae (Wolf spider), Theridiidae, Araneidae, Agelenidae, Sparassidae and Nephilidae one species each.

Diversitas Kapang Serasah Daun Talok (Muntingia calabura L.) Di Kawasan Desa Sukolilo Barat, Kecamatan Labang, Kabupaten Bangkalan, Madur

Leaf litter is one kind of substrate which is good for mold’s growth because of its organic matters content particularly cellulose. Research on mold diversity on Talok (Muntingia calabura L.) leaf litter which grow abundance at Sukolilo Barat Village, Labang Subdistrict, Bangkalan, Madura was conducted in order to determined the diversity and to isolate xerophilic mold as well as to examined the enzymatic activity of the isolates. The isolation has been done by direct and indirect method on DG18 agar, MEA, and OA from three samples which is taken purposively. The enzyme activities observed were cellulolytic, amylolitic and proteolytic at 310C temperature. The results showed that 24 isolates found were come from 3 genus i.e. Aspergillus, Curvularia and Fusarium. The Aspergillus was the largest number found. The Shannon-Wiener Index of Diversity showed that the diversity of three leaf litter samples categorized medium. The highest cellulolytic, amylolitic and proteolytic activity at 310C incubation were showed by A. tamarii (ISM 1), A.aculeatus (ISM 10) , A. terreus sp. 3 (ISM 17) respectively. Keywords : Diversity, mold, talok litter leaf, Madura

COMPARISON BETWEEN DEATH AND LIVING LAND MOLLUSK ASSEMBLAGES IN SIX FORESTED HABITATS IN NORTHERN ITALY

In order to assess taphonomic pathways leading to preservation of land snail assemblages, the agreement between the death (DAs) and living assemblages (LAs) of land mollusk communities was evaluated in six forest habitats along an altitudinal and soil acidity gradient in Northern Italy, using data obtained by visual search and sorting of leaf litter and soil. Death assemblages were considered both as overall DAs and as DAs consisting solely of pristine (i.e., fresh) shells. Both calcareous and acidic soils showed high fidelity in richness and evenness, in particular leaf litter and soil samples, as can be expected in depositional environments with reduced time averaging. Lack of rank-order agreement in species relative abundance was observed in visual search (r = 20.37-0.45), while significantly high rank-order agreement (r = 0.61-0.89) in leaf litter and soil. Time averaging and interspecific variation in life span and in shell durability appear to determine the observed live-dead mismatch, which, in contrast, was probably not affected by between-habitat transport and temporal changes in community composition. Between-habitat differences are generally preserved in the DAs. DAs based on pristine shells do not show higher rank abundance correlations and smaller differences in ordinations than DAs based on all shells. But in terms of species richness and evenness, DAs composed only of pristine shells were more similar to the LA, in particular in leaf litter and soil, supporting terrestrial ecologists' approach in considering pristine shells in inventories of species richness. Distinguishing between pristine and worn empty shells is especially useful for actualistic studies in highly calcareous sites, where DAs are expected to encompass a longer temporal duration.

Oak-insect herbivore interactions along a temperature and precipitation gradient

The interactions between herbivorous insects and their host plants are expected to be influenced by changing climates. Modern oaks provide an excellent system to examine this assumption because their interactions with herbivores occur over broad climatic and spatial scales, they vary in their defensive and nutritional investment in leaves by being deciduous or evergreen, and their insect herbivores range from generalists to highly specialized feeders. In this study, we surveyed leaf-litter samples of four oak species along an elevation gradient, from coastal northern California, USA, to the upper montane woodlands of the Sierra Nevada, to examine the relationship between climatic factors (mean annual temperature and precipitation) and oak herbivory levels at multiple scales; across all oak species pooled, between evergreen and deciduous species and within species.Overall, temperature and precipitation did not appear to have a significant effect on most measures of total herbivore damage (percent leaves damaged per tree, percent leaf area removed and average number of feeding damage marks per leaf) and the strongest predictor of herbivore damage overall was the identity of the host species. However, increases in precipitation were correlated with an increase in the actual leaf area removed, and specialized insects, such as those that make leaf mines and galls, were the most sensitive to differences in precipitation levels. This suggests that the effects of changing climate on some plant–insect interactions is less likely to result in broad scale increases in damage with increasing temperatures or changing precipitation levels, but is rather more likely to be dependent on the type of herbivore (specialist vs. generalist) and the scale (species vs. community) over which the effect is examined.

Analysis of Ant Communities Comparing Two Methods for Sampling Ants in an Urban Park in the City of São Paulo, Brazil

This study aimed to analyze the species composition and functional groups of the ant community and to assess the efficiency of two sampling methods, pitfall and leaf litter sampling, in an urban park. A total of 1,401 ants were collected, which belonged to six subfamilies and 36 species. The predominant species was Wasmannia auropunctata (present in 45.36% of the samples), while the functional group of opportunistic ants were the most frequent (present in 83.75% of the samples) and abundant (95.29% of the total collected specimens) functional group. The Jaccard Similarity Index showed a low similarity between the two sampling methods, as the difference of the number of individuals for each species between these two methods was not significant in only one case (Linepithema sp. 1, p = 0.4561). The fungusgrowing and cryptic ants were more collected in leaf litter samples (p<0.0001; p = 0.0348 respectively). Although there was no significant difference (p = 0.6397) between the two sampling methods for the total individuals of opportunistic ants, more species of this group were collected in pitfall traps. This difference was not significant because of the high presence of W. auropunctata, an opportunistic ant, in samples of leaf litter. Due to the predominance of tramp ants in the studied area, this article illustrates the importance of green urban areas in ant control strategies, since these sites could be used as a source of new colonization for these ants. Furthermore, the combination of the two sampling methods seems to be complementary for obtaining a more complete picture of the ant community.

Two new species of Cosmolaelaps Berlese (Acari:Laelapidae) from Iran.

This paper reports on two species of mites of the genus Cosmolaelaps Berlese, 1903 in Iran--C. dorfakiensis sp. nov., and C. pinnatus sp. nov., extracted from soil and leaf litter samples in Guilan Province, Northern Iran. A key to the species of Cosmolaelaps occurring in the Iran is also provided.

Effects of management intensity on ant diversity in cocoa plantation (Oume, centre west Côte d’Ivoire)

Anthropogenic habitat modifications, including conversion of forest to agricultural production cause losses of native species. In this study we examined the losses suffered by ant communities in relation to the intensity of management in cocoa plantations established in former tropical forest. An extensive sampling protocol consisting of pitfall trapping, leaf litter sampling, soil sampling and hand sampling was used to characterize ant species richness and composition in the native forest and compare it with three cocoa farms differing in their management intensity. Species richness was negatively correlated with management intensity and differed greatly between management practices and the forest. Two subfamilies (Myrmicinae and Amblyoponinae) showed a significant negative correlation with agricultural intensification probably because their species are constrained to living in forest like habitat. The species composition differed greatly between management practices and the forest. Intensively and moderately managed cocoa plantations were most dissimilar to the forest. In contrast, forest ants were well represented in the least intensively managed plantation. Overall, the findings of this study show that only slightly managed cocoa plantations sustain an ant diversity that comes close to that of the forest. This also holds true for cocoa plantations on former agricultural, and thus previously heavily used, land. The findings may help in the conservation of biodiversity as management practices most likely to sustain forest like ant communities have been identified.

Using metabarcoding to ask if easily collected soil and leaf-litter samples can be used as a general biodiversity indicator

The targeted sequencing of taxonomically informative genetic markers, sometimes known as metabarcoding, allows eukaryote biodiversity to be measured rapidly, cheaply, comprehensively, repeatedly, and verifiably. Metabarcoding helps to remove the taxonomic impediment, which refers to the great logistical difficulties of describing and identifying species, and thus promises to improve our ability to detect and respond to changes in the natural environment. Now, sampling has become a rate-limiting step in biodiversity measurement, and in an effort to reduce turnaround time, we use arthropod samples from southern China and Vietnam to ask whether soil, leaf litter, and aboveground samples provide similar ecological information. A soil or leaf-litter sample can be collected in minutes, whereas an aboveground sample, such as from Malaise traps or canopy fogging, can require days to set up and run, during which time they are subject to theft, damage, and deliberate contamination. Here we show that while the taxonomic compositions of soil and leaf-litter samples are very different from aboveground samples, both types of samples provide similar ecological information, in terms of ranking sites by species richness and differentiating sites by beta diversity. In fact, leaf-litter samples appear to be as or more powerful than Malaise-trap and canopy-fogging samples at detecting habitat differences. We propose that metabarcoded leaf-litter and soil samples be widely tested as a candidate method for rapid environmental monitoring in terrestrial ecosystems.

Effects of the annual invasive plant Impatiens glandulifera on the Collembola and Acari communities in a deciduous forest

Abstract Invasive plants can disturb interactions between soil organisms and native plants and thereby alter ecosystem functions and/or reduce local biodiversity. Collembola and Acari are the most abundant microarthropods in the leaf litter and soil playing a key role in the decomposition of organic material and nutrient cycling. We designed a field experiment to examine the potential effects of the annual invasive plant Impatiens glandulifera on species diversity, abundance and community composition of Collembola and Acari in leaf litter and soil in a deciduous forest in Switzerland. Leaf litter and soil samples were obtained from plots invaded by I. glandulifera since 6 years, from plots in which the invasive plant had been removed for 4 years and from plots which were not yet colonized by the invasive plant. The 45 leaf litter and soil samples were equally distributed over three forest areas, which were differently affected by a wind throw 12 years prior to sampling representing a natural gradient of disturbance. Collembola species richness and abundance in the leaf litter and soil samples were not affected by the presence of the invasive plant. However, the species composition of Collembola was altered in plots with I. glandulifera . The abundance of leaf-litter dwelling Acari was increased in invaded plots compared to the two other plot types. Furthermore, the presence of the invasive plant shifted the composition of Acari individuals belonging to different groups. Our field experiment demonstrates that an annual invasive plant can affect microarthropods which are important for nutrient cycling in various ecosystems.

The effect of latitudinal gradient on the species diversity of Chinese litter-dwelling thrips.

To understand the global distribution patterns of litter-dwelling thrips, a total 150 leaf litter samples were collected from 6 natural reserves located in three climatic regions, temperate, subtropical and tropical. The results showed the relative abundance of Thysanoptera was over 3.0% in 4 natural reserves from subtropical and tropical zone, and reached 5.9% in one tropical reserve, only less than Acarina and Collembola. In contrast it was only 0.3% in the warm temperate natural reserves, and no thrips were collected in a mid temperate reserve. The order on the average species numbers per plot of litter thrips was tropic > subtropics > temperate (n=25, p<0.05). Mean density of litter thrips per plots in the tropics and subtropics was significantly higher than that in the temperate region (n=25, p<0.05), but the average density was not significantly different between tropical and subtropical zones (n=25, p>0.05). The diversity of litter thrips in the tropics and subtropics was much higher than that in the temperate area based on comparsions of Shannon-Wiener diversity index (H’), Pielou eveness index (J), and Simpson dominance index (D). All of these results indicated that litter-dwelling thrips lived mainly in tropical and subtropical regions; meanwhile, species number and relative abundance increased with decreasing latitude.