scholarly journals Relative Efficiency of Pitfall Trapping vs. Nocturnal Hand Collecting in Assessing Soil-Dwelling Spider Diversity along A Structural Gradient of Neotropical Habitats

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 81 ◽  
Author(s):  
Kaïna Privet ◽  
Vincent Vedel ◽  
Claire Fortunel ◽  
Jérôme Orivel ◽  
Quentin Martinez ◽  
...  
Keyword(s):  
Habitat Complexity ◽  
Habitat Structure ◽  
French Guiana ◽  
Sampling Method ◽  
Species Turnover ◽  
Taxonomic Diversity ◽  
Forest Edge ◽  
Pitfall Trapping ◽  
Tropical Environments ◽  
Undisturbed Forest

Assessing spider diversity remains a great challenge, especially in tropical habitats where dozens of species can locally co-occur. Pitfall trapping is one of the most widely used techniques to collect spiders, but it suffers from several biases, and its accuracy likely varies with habitat complexity. In this study, we compared the efficiency of passive pitfall trapping versus active nocturnal hand collecting (NHC) to capture low understory-dwelling spider taxonomical (morpho-species) and functional (hunting guilds) diversity along a structural gradient of habitats in French Guiana. We focused on four habitats describing a structural gradient: garden to the orchard to the forest edge to the undisturbed forest. Overall, estimated morpho-species richness and composition did not vary consistently between habitats, but abundances of ground-hunting spiders decreased significantly with increasing habitat complexity. We found habitat-dependence differences in taxonomic diversity between sampling strategies: NHC revealed higher diversity in the orchard, whereas pitfalls resulted in higher diversity in the forest. Species turnover resulted in high dissimilarity in species composition between habitats using either method. This study shows how pitfall trapping is influenced by habitat structure, rendering this sampling method incomplete for complex, tropical environments. However, pitfall traps remain a valuable component of inventories because they sample distinct assemblage of spiders.

scholarly journals At each site its diversity: DNA barcoding reveals remarkable earthworm diversity in neotropical rainforests of French Guiana

2020 ◽  
Author(s):  
Marie-Eugénie Maggia ◽  
Thibaud Decaëns ◽  
Emmanuel Lapied ◽  
Lise Dupont ◽  
Virginie Roy ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
French Guiana ◽  
Species Turnover ◽  
Regional Scale ◽  
Dna Barcodes ◽  
Tropical Environments ◽  
Key Drivers ◽  
Dispersal Limitations ◽  
Very High

AbstractDespite their recognized essential role in soil, earthworms in tropical environments are still understudied. The aim of this study was to re-evaluate the diversity at the regional scale, as well as to investigate the environmental and spatial drivers of earthworm communities. We sampled earthworm communities across a range of habitats at six locations in French Guiana using three different sampling methods. We generated 1675 DNA barcodes and combined them with data from a previous study. Together, all sequences clustered into 119 MOTUs which were used as proxy to assess species richness. Only two MOTUs were common between the six locations and 20.2 % were singletons, showing very high regional species richness and a high number of rare species. A canonical redundancy analysis was used to identify key drivers of the earthworm community composition. The RDA results and beta-diversity calculations both show strong species turnover and a strong spatial effect, resulting from dispersal limitations that are responsible for the current community composition. Sampling in different microhabitats allowed the discovery of 23 MOTUs that are exclusively found in decaying trunks and epiphytes, highlighting hidden diversity of earthworms outside of soil.

scholarly journals Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

2018 ◽  
Author(s):  
Mauro Gobbi ◽  
Valeria Lencioni
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Aquatic Insect ◽  
Taxonomic Diversity ◽  
Carabid Beetles ◽  
Species Assemblages ◽  
Glacier Foreland ◽  
Distributional Patterns ◽  
Glacier Front ◽  
Spatio Temporal

Carabid beetles and chironomid midges are two dominant cold-adapted taxa, respectively on glacier forefiel terrains and in glacial-stream rivers. Although their sensitivity to high altitude climate warming is well known, no studies compare the species assemblages exhibited in glacial systems. Our study compares diversity and distributional patterns of carabids and chironomids in the foreland of the receding Amola glacier in central-eastern Italian Alps. Carabids were sampled by pitfall traps; chironomids by kick sampling in sites located at the same distance from the glacier as the terrestrial ones. The distance from the glacier front was considered as a proxy for time since deglaciation since these variables are positively correlated. We tested if the distance from the glacier front affects: i) the species richness; ii) taxonomic diversity; and iii) species turnover. Carabid species richness and taxonomic diversity increased positively from recently deglaciated sites (those c. 160 m from the glacier front) to sites deglaciated more than 160yrs ago (those located >1300 m from glacier front). Species distributions along the glacier foreland were characterized by mutually exclusive species. Conversely, no pattern in chironomid species richness and turnover was observed. Interestingly, taxonomic diversity increased significantly: closely related species were found near the glacier front, while the most taxonomically diverse species assemblages were found distant from the glacier front. Increasing glacial retreat differently affect epigeic and aquatic insect taxa: carabids respond faster to glacier retreat than do chironomids, at least in species richness and species turnover patterns.

scholarly journals Surveys of the bee (Hymenoptera: Apiformes) community in a Neotropical savanna using pan traps

2020 ◽  
Vol 60 ◽  
pp. e20206031
Author(s):  
Thaís Andrade Viana ◽  
Anete Pedro Lourenço
Keyword(s):  
North America ◽  
Habitat Complexity ◽  
Sampling Method ◽  
Cost Effective ◽  
Neotropical Savanna ◽  
Tropical Regions ◽  
Bee Community ◽  
Pan Traps ◽  
Bee Abundance ◽  
Local Habitat

Bee populations are declining because of various synergistic threats, and therefore bee survey and monitoring programs are needed. Several techniques have been developed to survey bees, but the most cost-effective and suitable methods to sample bees in several sites at the same time are passive approaches, such as methods involving colored pan traps (also known as Moericke or bowl traps). Several bee surveys using pan traps have been conducted in North America, Europe, and Australia, but only a few such surveys have been done in tropical regions. We used colored pan traps (blue, yellow, and white) to assess the bee community in the Brazilian savanna ecosystem in Rio Preto State Park. Sampling was conducted in October 2013 and March 2014 along permanent trails. We also characterized the local habitat of each trail, and then we compared bee abundance with habitat complexity. In total, 187 individual bees (n = 15 species) were collected, mainly using blue and white traps. Although we were not able to sample most species that were previously recorded in this park, the pan trap method can be used to survey and monitor bee assemblages in combination with another sampling method. Habitat complexity also affected the numbers of bees sampled using the pan traps, and more bees were collected at open sites.

Comparison of ground beetles (Coleoptera: Carabidae) and spiders (Araneae) collected in pan and pitfall traps

2003 ◽  
Vol 135 (4) ◽  
pp. 609-611 ◽  
Author(s):  
Christopher M. Buddle ◽  
H.E. James Hammond
Keyword(s):  
Sampling Method ◽  
Ground Beetles ◽  
Carabid Beetles ◽  
Pitfall Traps ◽  
Pitfall Trapping ◽  
Related Research ◽  
Pan Traps

Pitfall trapping is a widely used sampling method for biodiversity-related research of ground-dwelling arthropods. The trap is a container, usually with a preservative, that is sunk into the ground to collect arthropods which happen upon the trap perimeter and fall in (Lemieux and Lindgren 1999; Work et al. 2002). Two types receive the most use: deep circular pitfall traps and shallow rectangular pan traps (Marshall et al. 2001). The preserving fluid can influence trap efficacy (Deville and Wheeler 1998). Our objectives were to compare the efficiency of pitfall and pan traps with and without detergent in the preserving fluid (Marshall et al. 1994), using carabid beetles (Coleoptera: Carabidae) and spiders (Araneae) as focal taxa.

The effect of increased ground-level habitat complexity on mouse population dynamics

2003 ◽  
Vol 30 (6) ◽  
pp. 565 ◽  
Author(s):  
A. D. Arthur ◽  
R. P. Pech ◽  
A. Drew ◽  
E. Gifford ◽  
S. Henry ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Native Species ◽  
Habitat Complexity ◽  
Habitat Structure ◽  
Ground Level ◽  
Low Complexity ◽  
Mouse Population ◽  
Introduced Predators ◽  
The Impact

We investigated experimentally the influence of habitat structure on the population dynamics of house mice. Three habitat types were used. In one, dense stands of regenerating cypress pine were felled and left in situ to cover at least 40% of experimental plots, providing high complexity at ground level; in another, dense stands of regenerating pine were left intact, providing low complexity at ground level; in the third, open grassland adjacent to dense stands of regenerating pine also provided low complexity at ground level. Mouse populations occurred at higher densities in felled pine plots compared with both the standing pine and grassland plots, consistent with the hypothesis that the presence of increased habitat complexity at ground level reduced the impact of predation. Even though populations responded to the felled pine, they dropped to very low densities over winter, suggesting that the habitat was still marginal for the persistence of mice, probably due to a lack of food. The results are discussed with reference to their implications for the influence that habitat structure may have on the impact of introduced predators on native species.

scholarly journals Distance from the Forest Edge Influences Soil Fungal Communities Colonizing a Reclaimed Soil Borrow Site in Boreal Mixedwood Forest

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 427 ◽  
Author(s):  
Tod Ramsfield ◽  
Philip-Edouard Shay ◽  
Tony Trofymow ◽  
Colin Myrholm ◽  
Bradley Tomm ◽  
...  
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Plant Pathogens ◽  
Forest Edge ◽  
Natural Forest ◽  
Fungal Communities ◽  
Saprotrophic Fungi ◽  
Reclaimed Soil ◽  
Undisturbed Forest ◽  
Mineral Soils

Soil fungi are important components of boreal forest ecosystems; for example, saprotrophic fungi regulate nutrient cycling, and mycorrhizal species facilitate nutrient uptake by plants. This study aimed to assess soil fungal communities in a reclaimed area and an adjacent natural mixedwood forest and to identify the distribution of taxa available for seedling colonization. Soil fungal microbiomes were assessed along three transects (from 10 m inside the interior of the undisturbed forest to 40 m inside the reclaimed area) and in the roots of small aspen within the natural forest. Using high-throughput deoxyribonucleic acid (DNA) sequencing of internal transcribed spacer amplicons, a total of 2796 unique fungal taxa were detected across fine roots, forest floor, and mineral soils collected along the transects, whereas 166 taxa were detected in the aspen roots from the natural forest. Within the interior of the forest, ectomycorrhizal fungi were more common, whereas in the reclaimed areas, arbuscular mycorrhizae and saprophytes were more common. This survey showed that natural areas of adjacent undisturbed forest can act as a source of ectomycorrhizal fungi for dispersal into reclaimed areas. Notably, soil fungal taxa colonizing the root systems of small aspen included species that are specifically associated with soils from the undisturbed forest (primarily ectomycorrhizae) or the reclaimed clearing (saprotrophs and plant pathogens).

The causes of extinction

1989 ◽  
Vol 325 (1228) ◽  
pp. 241-252 ◽  
Keyword(s):  
Fossil Record ◽  
Species Turnover ◽  
Rapid Evolution ◽  
Taxonomic Diversity ◽  
Species Selection ◽  
Biotic Factors ◽  
Taxonomic Distribution ◽  
Interacting Species ◽  
Fossil Evidence ◽  
Different Types

A species may go extinct either because it is unable to evolve rapidly enough to meet changing circumstances, or because its niche disappears and no capacity for rapid evolution could have saved it. Although recent extinctions can usually be interpreted as resulting from niche disappearance, the taxonomic distribution of parthenogens suggests that inability to evolve may also be important. A second distinction is between physical and biotic causes of extinction. Fossil evidence for constant taxonomic diversity, combined with species turnover, implies that biotic factors have been important. A similar conclusion emerges from studies of recent introductions of predators, competitors and parasites into new areas. The term ‘species selection’ should be confined to cases in which the outcome of selection is determined by properties of the population as a whole, rather than of individuals. The process has been of only trivial importance in producing complex adaptations, but of major importance in determining the distribution of different types of organisms. An adequate interpretation of the fossil record requires a theory of the coevolution of many interacting species. Such a theory is at present lacking, but various approaches to it are discussed.

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