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.

Is Resource Change a Useful Predictor of Carrion Insect Succession on Pigs and Humans?

2021 ◽  
Author(s):  
Blake M Dawson ◽  
James F Wallman ◽  
Maldwyn J Evans ◽  
Philip S Barton
Keyword(s):  
Species Richness ◽  
Ambient Temperature ◽  
Community Composition ◽  
Species Turnover ◽  
Rapid Change ◽  
Insect Species ◽  
Significant Positive Effect ◽  
Insect Community ◽  
Positive Effects ◽  
Positive Effect

Abstract Carrion is a dynamic and nutrient-rich resource that attracts numerous insect species that undergo succession due to the rapid change in the carrion resource. Despite this process being well-understood, few studies have examined resource change as a driver of carrion insect succession, and instead have focused on the effects of time per se, or on coarse, qualitative measures such as decay stage. Here we report on three field succession experiments using pig carcasses and human cadavers encompassing two winters and one summer. We quantified the effects of resource change (measured as total body score, TBS), carrion type, initial carrion mass, ambient temperature, and season on insect species richness and community composition. We found that all variables had an effect on different taxonomic or trophic components of the insect community composition, with the exception of initial carrion mass which had no effect. We found significant positive effects of TBS on beetle species richness and composition, while fly species richness was not significantly affected by TBS, but was by ambient temperature. TBS had a significant positive effect on all trophic groups, while ambient temperature also had a significant positive effect on the necrophages and predator/parasitoids. Our study indicates that resource change, as indicated by TBS, is an important driver of carrion insect species turnover and succession on carrion, and that TBS can provide information about insect ecological patterns on carrion that other temporal measures of change cannot.

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 Short-term vegetation responses to the first prescribed burn in an urban pine rockland preserve

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Brittany Harris ◽  
Ariel Freidenreich ◽  
Eric Betancourt ◽  
Krishnaswarmy Jayachandran
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Community ◽  
Native Species ◽  
Seedling Recruitment ◽  
Species Turnover ◽  
South Florida ◽  
Vegetation Density ◽  
Prescribed Burn ◽  
Short Term

Abstract Background Preserving fire-dependent ecosystems can mitigate biodiversity loss from urbanization, but prescribing fire is challenging near human habitation. Consequently, dereliction of fire-dependent forests is widespread in urban fragments. Natural disturbance-based management, like prescribing fire, is gaining global acceptance, yet it is unclear what affects prolonged exclusion have on the initial regeneration of isolated plant communities immediately after fire is reintroduced. We took advantage of the first prescribed low-intensity burn on a university pine rockland nature preserve in South Florida, USA, to gain insight. We measured the changes in plant community composition and vegetation cover 1 week before the prescribed burn, and again 1, 2, and 14 weeks after to assess the early and short-term stages of recovery. Results The fire consumed substantial leaf litter, surface fuels, and canopy leaves, increasing sunlight availability to the understory and exposing bare ground. Many woody plants perished within a week post-burn, particularly invasive shrubs; however, germinating and resprouting plant growth were rapid. By 14 weeks, vegetation covered more of the ground than before the burn, although the upper canopy remained relatively open. Rarefied species richness was recovered by 14 weeks but did not exceed pre-burn levels. Invasive species richness was also maintained post-burn. Despite no overall changes in the community structure, our correspondence analysis and analysis of similarity of the plant community suggest high species turnover from the pre-burn to the final community surveyed, with an intermediate turnover in between. Conclusion The endangered pine rockland ecosystem, like many fire-dependent ecosystems, is threatened by habitat loss and fire suppression. Managing urban preserves with periodic burns is essential for supporting habitat for endemic species while decreasing demands for manual and time-intensive maintenance. Our study demonstrates that seedling recruitment from early plantings of native species can contribute significantly and immediately to restoration efforts in a fire-excluded urban preserve; however, many changes were ephemeral. Supplemental burns are likely necessary to further reduce vegetation density and sustain changes to the community composition.

scholarly journals Biogeographic regionalization by spatial and environmental components: Numerical proposal

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253152
Author(s):  
Mayra Flores-Tolentino ◽  
Leonardo Beltrán-Rodríguez ◽  
Jonas Morales-Linares ◽  
J. Rolando Ramírez Rodríguez ◽  
Guillermo Ibarra-Manríquez ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Regional Scale ◽  
Floristic Composition ◽  
Plant Species Richness ◽  
Rare Plants ◽  
Environmental Drivers ◽  
Herbaceous Plant ◽  
Environmental Predictors ◽  
Biogeographic Regionalization

Regionalization through the analysis of species groups offers important advantages in conservation biology, compared to the single taxon approach in areas of high species richness. We use a systematic framework for biogeographic regionalization at a regional scale based on species turnover and environmental drivers (climate variables and soil properties) mainly of herbaceous plant species richness. To identify phytogeographic regions in the Balsas Depression (BD), we use Asteraceae species, a family widely distributed in Seasonally Dry Tropical Forest (SDTF) and the most diverse of the vascular plants in Mexico. Occurrence records of 571 species were used to apply a quantitative analysis based on the species turnover, the rate of changes in their composition between sites (β-Simpson index) and the analysis of the identified environmental drivers. Also, the environmental predictors that influence species richness in the SDTF were determined with a redundancy analysis. We identified and named two phytogeographic districts within the SDTF of the BD (Upper Balsas and Lower Balsas). According to the multi-response permutation procedure, floristic composition of the two districts differs significantly, and the richness of exclusive species in Upper Balsas was higher (292 species) than in the Lower Balsas (32 species). The proportion of Mg and Ca in the soil and the precipitation of the driest three-month period were the environmental factors with greatest positive influence on species richness. The division of geographic districts subordinated to the province level, based on diverse families such as Asteraceae, proved to be appropriate to set up strategies for the conservation of the regional flora, since at this scale, variation in species richness is more evident. Our findings are consistent with a growing body of biogeographic literature that indicates that the identification of smaller biotic districts is more efficient for the conservation of biodiversity, particularly of endemic or rare plants, whose distribution responds more to microhabitats variation.

scholarly journals High species turnover shapes anuran community composition in ponds along an urban-rural gradient

2020 ◽  
Author(s):  
Carolina Cunha Ganci ◽  
Diogo B. Provete ◽  
Thomas Püttker ◽  
David Lindenmayer ◽  
Mauricio Almeida-Gomes
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Urban Areas ◽  
Forest Cover ◽  
Species Turnover ◽  
Urban Environments ◽  
Rapid Expansion ◽  
Central Brazil ◽  
Negative Effect ◽  
Urban Rural

AbstractThe rapid expansion of urban areas in which natural and semi-natural areas are replaced by human infrastructure, such as buildings and streets, is a major threat to biodiversity worldwide. However, little is known about how the structure of biotic communities is affected by urbanization in the tropics. Here, we tested the effect of land use types in urban and peri-urban areas on frog species richness and community composition in central Brazil. We selected 20 ponds differing in size and surrounding levels of urbanization as well as natural forest cover. We then used a Poisson GLM and a distance-based Redundancy Analysis (db-RDA) to relate species richness and community composition, respectively, to environmental variables. Variation in species richness was best explained by pond size (positive effect) and amount of urbanization (negative effect) in the surrounding 500 m. Community composition was mainly driven by species turnover than by nestedness, with db-RDA showing that turnover was explained primarily by urban infrastructure and forest cover. Our results indicate that urbanization negatively influences species richness. Moreover, as the amount of urbanization increased, several species were replaced by others taxa that appear better adapted to urban environments. Our results indicate that maintaining large ponds with surrounding native vegetation in urban environments might be an effective strategy for conserving frog communities.

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.

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals Avian Breeding Season Diversity and Community Composition in Camden White Gum and Slash Pine Plantations

2021 ◽  
Author(s):  
Elizabeth J Messick ◽  
Christopher E Comer ◽  
Michael A Blazier ◽  
T Bently Wigley
Keyword(s):  
United States ◽  
Species Richness ◽  
Community Composition ◽  
Pinus Elliottii ◽  
The United States ◽  
Slash Pine ◽  
Planted Forests ◽  
Eucalyptus Plantation ◽  
Short Rotation Woody Crops ◽  
Eucalyptus Plantations

Abstract In the southern United States, some landowners have established plantations of eucalyptus (Eucalyptus spp.) and are managing them on short rotations (<15 years) to provide wood for fiber and other potential uses. Establishment of short-rotation woody crops dominated by nonnative species has implications for resident fauna in the United States that are largely unknown. We compared avifauna abundance, diversity, and community composition in newly established Camden white gum (Eucalyptus benthamii) plantations with slash pine (Pinus elliottii) plantations of the same age and height (one to two and six to seven years old, respectively) in southwestern Louisiana, USA. Species richness, diversity, and community composition in newly established eucalyptus plantations and six- to seven-year-old pines were similar. More birds were observed, and bird detections varied less in eucalyptus plantations. Indigo buntings (Passerina cyanea) and other shrub-associated species were detected more often in eucalyptus stands. In contrast, species that inhabit herbaceous-dominated communities, such as eastern meadowlarks (Sturnella magna), or that were associated with a dense graminoid community (e.g., Bachman’s sparrow [Peucaea aestivalis]) were detected less often in eucalyptus. Overall, breeding bird communities in eucalyptus plantations one to two years postestablishment differed little from plantations dominated by slash pine. Study Implications Compared with slash pine (Pinus elliottii Englem) plantations of similar age and height (one to two years and six to seven years old, respectively) we found one- to two-year-old eucalyptus (Eucalyptus benthamii Maiden & Cambage) plantations supported similar avian species richness and diversity to six- to seven-year-old pine stands. Furthermore, we found these eucalyptus plantations (E13) supported an avian community that was intermediate to similar aged pine (S13) and pine of similar height (S08). However, avian communities will likely change as eucalyptus plantations age (Christian et al. 1997). Continued monitoring and assessment of community composition, richness, and abundance is important for determining the magnitude of this change. Future investigations focused on nest success, fecundity, postfledging monitoring, and survivorship compared with other types of planted forests and native cover types would help us better understand eucalyptus plantation effects on avifauna demographics (Van Horne 1983, Martin 1998, Jones 2001, Wood et al. 2004, Sage et al. 2006, Riffell et al. 2011).

scholarly journals Arthropod community structure in pastures of an island archipelago (Azores): looking for local–regional species richness patterns at fine-scales

2004 ◽  
Vol 94 (2) ◽  
pp. 111-121 ◽  
Author(s):  
P.A.V. Borges ◽  
V.K. Brown
Keyword(s):  
Species Richness ◽  
Regional Scale ◽  
Local Scale ◽  
Local Species Richness ◽  
Β Diversity ◽  
Arthropod Species ◽  
Α Diversity ◽  
Local Species ◽  
Richness Patterns

AbstractThe arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local–regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= α diversity) and regional species richness was estimated at the pasture level (= γ diversity) with the ‘first-order-Jackknife’ estimator. Three related issues were addressed: (i) the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii) quantification of the relative contributions of α and β diversity to regional diversity using additive partitioning; and (iii) the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing β-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.

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