Leaf Litter Extraction Research Articles

The ants (Hymenoptera: Formicidae) of a one-hectare plot of lowland dipterocarp forest

A multiple-method survey of just one hectare of lowland dipterocarp forest in Brunei yielded 115 species or morphospecies of ants of which 102 have been identified to species. No fewer than 24 of these are new records for Borneo. We list these species with comments on their wider distributions. Almost half of these species (44%) are endemic to the Sundaland region, with a further 20% restricted to south-east Asia. Few local species crossed the Makassar Strait between Borneo and Sulawesi suggesting that Wallace's Line is a relevant biogeographical barrier for many ant species. The trapping methods used generally targeted contrasting groups of species. The methods that yielded most ant species were canopy knockdown using pyrethrin insecticide (43%), pitfall trapping (26%), leaf litter extraction (9.5%) and bark spraying (8.6%). Our results suggest that future tropical forest ant surveys should include canopy sampling.

Rove beetle diversity and coffee agroecosystems in the Colombian Andes

AbstractThe intensification of coffee plantations has driven biodiversity loss worldwide, but little is known about how it affects the ecological structure of Andean rove beetle communities. The rove beetle diversity was estimated in a coffee‐intensification gradient located on the western slope of Central Andes (1300–1800 m elevation). Sixteen sampling sites in four land uses were selected: four native forest patches and twelve coffee production systems (four polygeneric shade coffee plantations, four monogeneric shade coffee plantations, and four sun‐grown coffee plantations). We used unbaited pitfall traps and leaf litter extraction and recorded environmental and vegetation variables in each land use. 101 staphylinid species were collected in 12 subfamilies and 45 genera (N = 522 individuals). We recorded for the first time the subfamily Leptotyphlinae in Colombia. Anotylus sp. 1 was the most abundant species with about 16% of the total individuals, while 60% of the remaining species showed <2 individuals. Native forest and polygeneric shade coffee plantations were more diverse than monogeneric shade and sun‐grown coffee plantations (for all qD measures). Monogeneric shade coffee plantations were the least diverse in all studies. Species composition was different between forests and coffee plantations, and the sun‐grown coffee had a low number of exclusive species. The rove beetle diversity did not show a linear reduction with the intensification levels of the coffee plantation, and the sun‐grown coffee did not represent an absolutely hostile environment. We discuss the role of staphylinid as model group for comparative ecological studies in the tropical agricultural landscape.

Effects of environmental variables on the composition of ants (Hymenoptera: Formicidae) in Amazonian foothills forest

Abiotic factors can negatively or positively affect the structure of communities; studying these factors is important to identify the causes that structure ant communities; taking into account this situation and that in the Amazon foothills region, particularly in the Putumayo department, few studies have been carried out and there is insufficient knowledge about the ecology of many species, this research was aimed to evaluate the effect of environmental variables in the assembly of ants, evaluating the hypothesis: the assembly of forest and grassland ants reflect changes in environmental variables (ambient temperature, soil temperature and relative humidity). In the municipality of Orito, in a secondary forest of the Amazon foothills and its grassland matrix, a 100 m transect was traced, locating 10 stations 10 m apart, in these, ants were sampled with: pitfall traps, corner baits: arboreal, epigeal and hypogeal, leaf litter extraction and manual capture. With the averages of the environmental variables in each station and the diversity and richness data per month of sampling, the Poisson regression analysis was performed and with the data of the morphospecies and the averages of the measured variables, the principal component analysis was performed. The results indicated that, the ants assemblages did not reflect the changes of the variables, some species responded to these patterns. Therefore, to understand the dynamics of the functioning of the ecosystems of the Amazonian foothills, it is necessary to study the biology of each species; However, it was determined that, the habitats studied share generalist species and contain exclusive species that contribute to the diversity of ants in the Amazonian foothills, consequently the sites must be conserved.

Ants of the Hengduan Mountains: a new altitudinal survey and updated checklist for Yunnan Province highlight an understudied insect biodiversity hotspot.

China’s Hengduan Mountain region has been considered one of the most diverse regions in the northern hemisphere. Its stunning topography with many deep valleys and impassable mountain barriers has promoted an astonishing diversification in many groups of organisms including plants, birds, mammals, and amphibians. However, the insect biodiversity in this region is still poorly known. Here, the first checklist of ant species from the Southern Hengduan Mountain region is presented, generated by sampling ant diversity using a wide array of collection methods, including Winkler leaf litter extraction, vegetation beating, and hand collection. 130 species/morphospecies from nine subfamilies and 49 genera were identified. Among them, 17 species from 13 genera represent new records for Yunnan province, and eight species are newly recorded for China. Moreover, we believe 41 novel morphospecies (31% of the total collected taxa) will prove to be new to science. These results highlight the rich ant fauna of this region and strongly support its status as a biodiversity hotspot. The current ant species checklist for the whole of Yunnan Province was updated by recording 550 named species from 99 genera. Taken together, our results suggest that the Yunnan ant fauna still remains under-sampled, and future sampling will likely yield many more species, among them many undescribed ones.

A preliminary checklist of spiders (Araneae: Arachnida) in Jambughoda Wildlife Sanctuary, Panchmahal District, Gujarat, India

Studies relating to spiders in Gujarat have been sporadic and most of the spider documentation have been done from agriculture fields, wetlands and few from protected areas. One such undocumented area was Jambughoda Wildlife Sanctuary, Panchmahal District, Gujarat. Therefore, a study to document the spider diversity was carried out in Jambughoda Wildlife Sanctuary from July 2012 to October 2015. A combination of four sampling methods namely, belt transect along with hand-pick method, pitfall sampling, vegetation beating and leaf litter extraction were used for collection of spiders from different strata. During the study, a total of 138 species belonging to 90 genera and 29 families were recorded from the study area. Of which, 21 species and 17 genera were recorded for the first time from Gujarat State. The theridiid genus Cephalobares O. Pickard-Cambridge, 1870 was recorded for the first time from India. The families Araneidae, Salticidae, Theridiidae and Oxyopidae were found to be dominant in the area. We recognized seven feeding guilds namely ambushers, foliage runners, ground runners, orb weavers, sheet web-builders, space web-builders and stalkers. Amongst these, orb-weavers, stalkers and ground runners were dominant. This documentation, however, forms the baseline information for spiders of Jambughoda WLS, suggesting the great diversity of the spider fauna in this protected area, which can be further explored.

Restoration of riparian forest corridors: eight years monitoring the diversity of soil ants in an Andean rural landscape

Abstract Ecological restoration of riparian forest corridors at the landscape scale can facilitate recruitment of certain flora and fauna, thus possibly helping to maintain viable wildlife populations. We evaluated ecological restoration of three corridors between two protected Andean forests. Soil ants and eight environmental variables focused on edaphic conditions were monitored for 8 years following restoration activity. Soil ants were collected in pitfall traps and by leaf litter extraction on 21 plots classified into five types of habitat: large forest patches, riparian forests, two types of restoration corridors on former timber and pasture land (R‐Forestry and R‐Pasture, respectively), and Pasture. A total of 132 ant species belonging to 40 genera were found. Among these, 112 species were found in Forests, 105 in Riparian, 80 in R‐Forestry, 79 in R‐Pasture and 63 in Pasture. Composition analyses (canonical correspondence analysis and NMDS) showed that the ant community in restoration corridors and pastures is far from resembling that of the forests. Yet, there is biological progress with respect to the Pasture. Gnamptogenys bisulca and Pheidole pygmaea were indicator species for advanced restoration progress because of their close association to forests, while Linepithema piliferum indicated a reversal of restoration progress due to its preference for open habitats. Since both ant richness and composition in restored areas do not yet resemble the reference forest ecosystem, we suggest that other interventions such as restoring wider corridors and changing to wild‐friendly agriculture around the reserves might improve restoration efforts in Andean landscapes.

Relative and absolute density estimates of land planarians (Platyhelminthes, Tricladida) in urban rainforest patches

Land planarians (Platyhelminthes) are likely important components of the soil cryptofauna, although relevant aspects of their ecology such as their density remain largely unstudied. We investigated absolute and relative densities of flatworms in three patches of secondary Brazilian Atlantic rainforest in an urban environment. Two methods of sampling were carried out, one consisting of 90 hours of active search in delimited plots covering 6,000 m² over a year, and the other consisting of leaf litter extraction from a 60 m² soil area, totaling 480‑600 l leaf litter. We found 288 specimens of 16 species belonging to the genera Geobia, Geoplana, Issoca, Luteostriata, Obama, Paraba, Pasipha, Rhynchodemus, Xerapoa, and the exotic species Bipalium kewense and Dolichoplana striata. Specimens up to 10 mm long were mostly sampled only with the leaf litter extraction method. Absolute densities, calculated from data obtained with leaf litter extraction, ranged between 1.25 and 2.10 individuals m‑². These values are 30 to 161 times higher than relative densities, calculated from data obtained by active search. Since most common sampling method used in land planarian studies on species composition and faunal inventories is active search for a few hours in a locality, our results suggest that small species might be overlooked. It remains to be tested whether similar densities of this cryptofauna are also found in primary forests.

RELATIVE AND ABSOLUTE DENSITY ESTIMATES OF LAND PLANARIANS (PLATYHELMINTHES, TRICLADIDA) IN URBAN RAINFOREST PATCHES

Land planarians (Platyhelminthes) are likely important components of the soil cryptofauna, although relevant aspects of their ecology such as their density remain largely unstudied. We investigated absolute and relative densities of flatworms in three patches of secondary Brazilian Atlantic rainforest in an urban environment. Two methods of sampling were carried out, one consisting of 90 hours of active search in delimited plots covering 6,000 m² over a year, and the other consisting of leaf litter extraction from a 60 m² soil area, totaling 480-600 l leaf litter. We found 288 specimens of 16 species belonging to the genera Geobia, Geoplana, Issoca, Luteostriata, Obama, Paraba, Pasipha, Rhynchodemus, Xerapoa, and the exotic species Bipalium kewense and Dolichoplana striata. Specimens up to 10 mm long were mostly sampled only with the leaf litter extraction method. Absolute densities, calculated from data obtained with leaf litter extraction, ranged between 1.25 and 2.10 individuals m-2. These values are 30 to 161 times higher than relative densities, calculated from data obtained by active search. Since most common sampling method used in land planarian studies on species composition and faunal inventories is active search for a few hours in a locality, our results suggest that small species might be overlooked. It remains to be tested whether similar densities of this cryptofauna are also found in primary forests.

Effects of leaf litter extraction fluid from dominant forest tree species on functional characteristics of soil microbial communities

The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and synergism between plants and soil contribute to the process of forest succession. Leaf litter from dominant tree species at different stages of succession were collected and extracted with sterile deionized water. After treating the soil of abandoned land with the different extraction fluids, we analyzed changes in carbon utilization of the soil microbial community in Biolog EcoPlates, then considered these results with those of our previous study on forest vegetation succession in the Malan forest. The leaf litter enhanced the metabolic capacity and functional diversity of the soil microbes, especially in the following combinations: the leaf litter of Quercus liaotungensis–Pinus tabulaeformis, P. tabulaeformis–Betula platyphylla, Q. liaotungensis and P. tabulaeformiss. Second, when litter from one species evaluated, the species enhanced metabolism and diversity in the order of their successional relationship: B. Platyphylla < P. tabulaeformis < Q. liaotungensis. After soils were treated with different leaf litters at 25 °C for 7 days, the sorting pattern of the PCA values, based on the similarity of carbon source utilization by the soil microbes, corresponded to the successional pattern on the basis of the similarity of community composition of forest plants. Thus, changes in soil properties caused by leaf litter from different dominant trees probably play a unique role in the successional pattern of a forest community. We thus propose a successional mechanism that underlies the natural succession process within the Malan forest region. When the dominant forest species of the climax successional stage develops during the early successional stages, its forest litter probably alters soil properties such that the soil becomes unsuitable for the gradual growth and regeneration of the original dominant tree species but promotes the growth and establishment of later-invasive plants. In this way, the originally dominant species is replaced by the newly dominant tree species during forest succession.

Ant (Hymenoptera: Formicidae) diversity and community composition along sharp urban forest edges

The effects of forest edge on ant species richness and community composition were examined within an urbanized area of northeast Ohio. The ground-dwelling ant fauna was inventoried in three deciduous forest fragments that have resulted from human disturbance. We surveyed ants via leaf-litter extraction along 150 m transects positioned perpendicular to the forest edge. We collected 4,670 individuals from 14 genera and 29 species. Samples closest to the forest edge contained more species and accumulated species at a higher rate than did samples located in the forest interior. Our rarefied and expected richness estimates revealed a decline of species richness from edge to forest interior. The higher ant richness at the forest edge was due mostly to the presence of species characteristic of the neighboring open habitats. Although most of the typical forest ant species were represented equally at the edge and at the forest interior, a few responded to the presence of edges with changes in their relative abundance and frequency of occurrence. Forest edges had a higher proportion of opportunistic species and a lower proportion of cryptic ants, whereas interior locations exhibited a more even distribution among ant functional groups. In addition, we documented a community composition shift between the edge and the forest interior. Consistent with previous findings, we suggest that the edge effects are most pronounced within 25 m of the forest edge, which may have implications for the overall conservation of forest-dwelling fauna.

Ant Diversity and Distribution in Acadia National Park, Maine

Exotic ant species are a primary threat to ant biological diversity, posing a negative impact to native ant communities. In this study, we examine species richness of ants (family Formicidae) in Acadia National Park, ME, as a fundamental step toward understanding the present impact of the exotic species Myrmica rubra on native ant species. Twelve habitat types were sampled, along six transects, with pitfall traps, visual searching, bait traps, and leaf litter extraction, and the aid of 34 volunteers. We report 42 species of ants in Acadia National Park, comprising five subfamilies (Amblyoponinae, Dolichoderinae, Formicinae, Myrmicinae, and Ponerinae) and 15 genera; the cataloged species represents 75% of the species originally recorded in the area by Procter (1946). Our findings suggest M. rubra is currently not a dominant species throughout the entire island. However, where this species has invaded locally, few competing native species coexist. The species Lasius alienus, Formica subsericea, Myrmica detritinodis, Camponotus herculeanus, Formica argentea, Formica aserva, and Tapinoma sessile occurred most often in our survey. We report the ant species Amblyopone pallipes and Dolichoderus mariae as two new records for the state of Maine.

An assessment of spider sampling methods in tropical rainforest fragments of the Anamalai hills, Western Ghats, India

Spiders are a highly diverse but poorly studied group of invertebrates in the tropics known to be sensitive indicators of habitat alterations. This study in three degraded tropical rainforest fragments in the southern Western Ghats assesses the utility of four sampling methods to document spider communities. Using belt transects, vegetation beating, leaf litter extraction, and pitfall traps, 103 spider morphospecies were detected in the three fragments. More species and individuals were recorded per unit effort in transects than vegetation beating, and in transects in the fragment with higher tree and shrub densities. Transects were also more appropriate for collection of natural history information and for identifying spiders to morphospecies. The composition of spider functional groups varied significantly across the four methods and a combination of methods is likely to yield a more complete inventory of the spider community.

Arthropod response to prescription burning at the soil–litter interface in oak–pine forests

In the southeastern U.S., forest managers are returning repetitive fire to the landscape to facilitate regeneration of desirable species. The increased use of prescribed fire generates questions regarding the effects of single- and multiple-burning events on leaf-litter and ground-dwelling arthropods, and recovery of these arthropods following fire disturbance. In this study, the effects of early season single- and multiple-burns were assessed on leaf-litter arthropods and ground-dwelling arthropods in oak–pine forests for two growing seasons following fire disturbance. Arthropods were sampled by leaf-litter extraction and pitfall trapping, where pitfall trapping was restricted to single-burned areas. For each sampling method, arthropod abundance, diversity, richness, and evenness were calculated at the family or ordinal level. Forest characteristics were also surveyed to measure impacts from the prescribed fires and to assess variability in the forest environment. Leaf-litter arthropod abundance was devastated by burning, and resurgence of populations was not evident until the second growing season in the multiple-burned areas. In single-burned plots, litter arthropod abundance remained low for the duration of the study possibly due to greater fire intensity relative to the multiple-burn plots. Leaf-litter arthropod diversity was not affected by either burn regime. Burning decreased leaf-litter arthropod richness and increased leaf-litter arthropod evenness, but these effects were only marginally significant. Prescription burning had no impact on ground-dwelling arthropod abundance, diversity, or richness, but arthropod community evenness increased following the single-burn disturbance. In the principal components analysis (PCA), burning was a major gradient explaining 46% of the variation in the data. Burning decreased leaf-litter cover and depth and lower canopy cover, and contributed to the variance explained by PCA. Our data confirm that prescription burning is accomplishing its management goal of removing undesirable lower-canopy cover in the mixed hardwood forests of the Cumberland Plateau. Following early-season, low-intensity burns, recovery of leaf-litter arthropods was not evident until two-growing seasons after fire disturbance. Any differences we observed could be attributed to lower fire intensity in forests that are repeatedly burned. Prescribed burns should be utilized on a rotation greater than 2 years to allow resurgence of the leaf-litter arthropod community and recovery of the leaf-litter habitat.

Distribution pattern of woodlice (Isopoda) and millipedes (Diplopoda) in four primeval forests of the Western Carpathians (Central Slovakia)

We collected 1605 isopod individuals (eight species) and 671 diplopod individuals (17 species) in four primeval forests of the Western Carpathians, Central Slovakia, by leaf litter extraction. The forests are of different temperate deciduous forest types varying in tree species, aspect, elevation and soil characteristics. The oak forests, established on southwest oriented slopes at an elevation of 280–600 m, were characterized by Hyloniscus riparius, Porcellium conspersum, Enantiulus nanus and Ophioiulus pilosus. The beech forests, established on northeast oriented slopes at an elevation of 700–1100 m, were characterised by Ligidium hypnorum, Trachysphaera costata and Polyzonium germanicum. A remarkable increase of the total number of species and individuals occurred in both forest types adjacent to coarse woody debris (CWD). Woodlice density close to CWD was between 200 and 630 individuals m −2 (35–130 individuals m −2 distant from CWD); millipede density close to CWD ranged from 60 to 230 individuals m −2 (15–75 individuals m −2 distant from CWD). Species richness of both taxa close to CWD varied from 13 to 16 species m −2 (7–12 species m −2 distant from CWD). Thus, CWD has a significant influence on saprophages. However, structural components such as CWD and the amount of leaf litter did not significantly alter species assemblages. Species at sites distant from CWD were a subset of species at sites close to CWD. According to a canonical correspondence analysis (CCA), ‘forest type’ and ‘elevation within a slope’, as well as chemistry of the upper soil layer, i.e. ‘acidification’ and ‘nutrition’, strongly influenced species assemblages.

A Survey of Ground-Dwelling Ants (Hymenoptera: Formicidae) in Georgia

Ground-dwelling ants (Hymenoptera: Formicidae) were sampled at 29 sites in 26 counties in Georgia with pitfall traps, leaf litter extraction, visual searching, and bait stations. We found 96 ant taxa including nine species not previously reported from Georgia: Myrmica americana Weber, M. pinetorum Wheeler, M. punctiventris Roger, M. spatulata Smith, Pyramica wrayi (Brown), Stenamma brevicorne (Mayr), S. diecki Emery, S. impar Forel, and S. schmitti Wheeler, as well as three apparently undescribed species (Myrmica sp. and two Stenamma spp.). Combined with previous published records and museum records, we increased the total number of ground-dwelling ants known from Georgia to 144 taxa.

Effects of Sampling Intensity on the Collection of Spider (Araneae) Species and the Estimation of Species Richness

In this study I compare the relative effectiveness of temporally and spatially constrained sampling strategies on the collection of spiders, and discuss how the sampling strategy used may affect estimates of spider species richness. Using 3 time-based collecting methods (ground sampling, above ground sampling, and vegetation beating) and 1 area-based method (Tullgren leaf litter extraction), 3 collectors sampled spiders from 10- by 50-m plots in a cove forest in the Ellicott Rock Wilderness Area of northern Georgia between 18 May and 4 June 1993. Eighty samples collected from four 10- by 50-m plots (0.2 ha) contained 77 species, and 77 samples from 24 such plots (1.2 ha) contained 78 species. A total of 2,842 adults spiders was collected from the 1.4 ha sampled, representing 92 species, 64 genera, and 20 families. Increasing the collecting effort per unit area (repetitive collecting) is a more efficient strategy for collecting cryptic or covert species as opposed to spreading the sampling effort over a larger area (nonrepetitive collecting). It is suggested that before arthropod assemblages are included in management decisions, the methods used to collect the species must be fully examined. Richness estimates for the site ranged from 85 to 144 species using the repetitive strategy, from 88 to 95 for the nonrepetitive strategy, and from 102 to 112 for the entire dataset.