scholarly journals Pollinator Species Richness Trends: No Decelerating Declines in Dutch Bees and Bumblebees

2017 ◽  
Author(s):  
Tom J. M. Van Dooren
Keyword(s):  
Species Richness ◽  
Temporal Trends ◽  
Species Accumulation Curves ◽  
Wild Bees ◽  
Species Numbers ◽  
Pollinator Species ◽  
Species Survival ◽  
Capture Recapture ◽  
Local Species ◽  
Accumulation Curves

AbstractTemporal trends (1946–2013) in the species richness of wild bees from the Netherlands are analysed. We apply two methods to estimate richness change which both incorporate models for sampling effects and detection probability. The analysis is repeated for records with specimens deposited in collections, and a subset restricted to spatial grid cells that have been sampled repeatedly across three periods. When fitting non-linear species accumulation curves to species numbers, declines are inferred for bumblebees and at most limited declines for other bees. Capture-recapture analysis applied to species encounter histories infers a constant colonization rate per year and constant (bumblebees) or decreasing (other) local species survival. However, simulations suggest that the method estimates time trends in survival with a negative bias. Species richness trends predicted by the second approach are a 10% reduction in non-Bombus species richness and 29% fewer Bombus species since 1946, comparable to the predictions of the first approach. Neither analysis provides reliable evidence that decelerating declines in species richness occur in these taxa. Therefore we should not infer decelerating declines in pollinator species richness in N-W Europe as previously claimed.

scholarly journals Predicting unknown species numbers using discovery curves

2007 ◽  
Vol 274 (1618) ◽  
pp. 1651-1658 ◽  
Author(s):  
Daniel P Bebber ◽  
Francis H.C Marriott ◽  
Kevin J Gaston ◽  
Stephen A Harris ◽  
Robert W Scotland
Keyword(s):  
New World ◽  
Statistical Approach ◽  
Species Accumulation Curves ◽  
Species Numbers ◽  
Unknown Species ◽  
Extant Species ◽  
Accumulation Curves ◽  
Species Descriptions ◽  
Total Species ◽  
Global Datasets

A common approach to estimating the total number of extant species in a taxonomic group is to extrapolate from the temporal pattern of known species descriptions. A formal statistical approach to this problem is provided. The approach is applied to a number of global datasets for birds, ants, mosses, lycophytes, monilophytes (ferns and horsetails), gymnosperms and also to New World grasses and UK flowering plants. Overall, our results suggest that unless the inventory of a group is nearly complete, estimating the total number of species is associated with very large margins of error. The strong influence of unpredictable variations in the discovery process on species accumulation curves makes these data unreliable in estimating total species numbers.

scholarly journals Comparison of forest regeneration in two sites with different primate abundances in Northwestern Ecuador

2016 ◽  
Vol 64 (2) ◽  
pp. 493 ◽  
Author(s):  
Bayron R. Calle-Rendón ◽  
Mika Peck ◽  
Sara E. Bennett ◽  
Citlalli Morelos-Juarez ◽  
Felipe Alfonso
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Forest Regeneration ◽  
Tree Diversity ◽  
Primate Species ◽  
Species Accumulation Curves ◽  
Dispersal Syndrome ◽  
Species Accumulation ◽  
Accumulation Curves ◽  
Understory Tree

There is increasing evidence that large-bodied primates play important roles as seed dispersers and in the maintenance of tree diversity in forest ecosystems. In this study we compared forest regeneration at two sites with differing primate abundances in the Ecuadorian Chocoan rainforest. We predicted: (1) significant differences in primate abundance between the two sites; (2) higher understory tree species richness and density at the site with greater primate abundance; (3) the site with lower primate abundance characterized by tree species dispersed by non-primate biotic agents and/or abiotic factors. We compared two sites, Tesoro Escondido (TE) a campesino cooperative, and the El Pambilar (EP) wildlife refuge that both maintain populations of mantled howler monkey (Alouatta palliata), the brown-headed spider monkey (Ateles fusciceps fusciceps) and the capuchin monkey (Cebus capucinus). We characterized canopy structure by point-quadrant sampling, determined primate abundance and sampled seedlings/saplings in 1 m2 plots, classifying tree species based on three dispersal syndromes: adapted for primate dispersal, dispersed by other biological agents, and abiotic dispersal. We compared sites in terms of primate abundance (groups and individuals observed per day) and regeneration characteristics (overall density, species richness, and dispersal syndrome). We carried out within site comparisons and constructed understory tree species accumulation curves. Overall the forests were structurally similar - with significantly higher densities of A. f. fusciceps at TE. Encounter rates for the other two primate species were similar at both sites. Understory tree density and species richness was significantly higher in TE with no stabilization of tree species accumulation curves. The species accumulation curve for understory trees at EP stabilized. Higher densities and species richness of primate dispersed tree species were observed at TE, with non-primate biotically dispersed tree species the dominant dispersal syndrome at both sites. Our observations are consistent with those from other studies investigating the role of large-bodied frugivorous primates in forest regeneration, and point to a general pattern: future lowland tropical forest tree diversity depends on maintaining robust populations of large primate species in these systems. It is highly probable that the maintenance of high levels of tree diversity in Chocoan rainforests is dependent on the conservation of its largest resident primate, the critically endangered brown-headed spider monkey (A. f. fusciceps).

scholarly journals Saprophytic flies in impacted areas of the Belo Monte Dam, Pará, Brazil (Diptera: Mesembrinellidae, Neriidae, Ropalomeridae, and Sarcophagidae): community composition, abundance, and species richness

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Camila Lorena Damasceno Queiroz ◽  
Caroline Costa De-Souza ◽  
Hermes Fonseca de Medeiros ◽  
William Leslie Overal ◽  
Arleu Barbosa Viana-Junior ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
New Record ◽  
New Records ◽  
Brazilian Amazon ◽  
Species Accumulation Curves ◽  
Xingu River ◽  
Hydroelectric Dam ◽  
Accumulation Curves ◽  
Belo Monte

Abstract: The present study aims to document the community composition, abundance, and species richness of saprophytic fly species (Mesembrinellidae, Neriidae, Ropalomeridae, and Sarcophagidae) of the Volta Grande region of the Xingu River, a poorly sampled area impacted by the Belo Monte hydroelectric dam. Five collecting trips were carried out between 2014 and 2016, when traps baited with fermenting bananas were used. A total of 154 specimens, three genera, and six species were collected of Mesembrinellidae; 196 specimens, three genera, and seven species of Neriidae; 272 specimens, three genera, and six species of Ropalomeridae; and 624 specimens, 22 species and 10 genera of Sarcophagidae. Species accumulation curves for all families except Sarcophagidae demonstrated a strong tendency towards stabilization, showing that sampling efforts were sufficient to record most of the targeted species. Laneela perisi (Mariluis, 1987) (Mesembrinellidae) is a new record for the state of Pará. Among Ropalomeridae, Apophorhynchus amazonensisPrado, 1966, is a new record for Pará. Among Sarcophagidae, Helicobia aurescens (Townsend, 1927) is newly recorded from the Brazilian Amazon, and Ravinia effrenata (Walker, 1861) and Titanogrypa larvicida (Lopes, 1935) are new records for Pará.

scholarly journals Estimation of the species richness of hyperdiverse beetles (Coleoptera: Cerambycidae) in an area of Atlantic Forest, Minas Gerais, southeastern Brazil

2019 ◽  
Vol 14 (4) ◽  
pp. 489-498
Author(s):  
Felipe Donateli Gatti ◽  
Marco Antonio Alves Carneiro
Keyword(s):  
Species Richness ◽  
Tropical Forests ◽  
Atlantic Forest ◽  
Southeastern Brazil ◽  
Biodiversity Hotspots ◽  
Species Accumulation Curves ◽  
The Family ◽  
Accumulation Curves ◽  
One Year ◽  
Collection Methods

Species are elementary units in community ecology studies. However, sample limitations obstruct the elaboration of accurate faunistic inventories, especially in biodiversity hotspots, such as tropical forests. In this way, the objective of this research was to describe the richness, using different non-parametric estimators of richness, in the family Cerambycidade, a group of hyperdiverse insects in the Atlantic Forest. Five hundred and eighty-one specimens belonging to 145 species and 3 subfamilies were collected. Among the species sampled, 46.2% were considered singletons, 13.8% doubletons, 48.95% unicates, 15.15% duplicates and 90.3% ecologically rare. The species accumulation curves did not stabilize, which was already expected considering that more species and individuals were sampled in the last months of collection. The estimated richness presented values much higher than the observed richness. This was a reflect of the high proportion of ecologically rare species present in the sample. This work showed that faunistic inventories of hyperdiverse groups, with only one year of collection and a single sampling methodology may underestimate the species richness of a region. Thus, larger time series associated with different collection methods are essential for a more accurate survey of biodiversity in the Atlantic Forest.

Estimating terrestrial biodiversity through extrapolation

1994 ◽  
Vol 345 (1311) ◽  
pp. 101-118 ◽  
Keyword(s):  
Species Richness ◽  
Difficult Problem ◽  
Species Assemblages ◽  
Species Accumulation Curves ◽  
Data Set ◽  
Local Species Richness ◽  
Wide Range ◽  
Biodiversity Inventories ◽  
Local Species ◽  
Terrestrial Biodiversity

Both the magnitude and the urgency of the task of assessing global biodiversity require that we make the most of what we know through the use of estimation and extrapolation. Likewise, future biodiversity inventories need to be designed around the use of effective sampling and estimation procedures, especially for ‘hyperdiverse’ groups of terrestrial organisms, such as arthropods, nematodes, fungi, and microorganisms. The challenge of estimating patterns of species richness from samples can be separated into (i) the problem of estimating local species richness, and (ii) the problem of estimating the distinctness, or complementarity, of species assemblages. These concepts apply on a wide range of spatial, temporal, and functional scales. Local richness can be estimated by extrapolating species accumulation curves, fitting parametric distributions of relative abundance, or using non-parametric techniques based on the distribution of individuals among species or of species among samples. We present several of these methods and examine their effectiveness for an example data set. We present a simple measure of complementarity, with some biogeographic examples, and outline the difficult problem of estimating complementarity from samples. Finally, we discuss the importance of using ‘reference’ sites (or sub-sites) to assess the true richness and composition of species assemblages, to measure ecologically significant ratios between unrelated taxa, to measure taxon/sub-taxon (hierarchical) ratios, and to ‘calibrate’ standardized sampling methods. This information can then be applied to the rapid, approximate assessment of species richness and faunal or floral composition at ‘comparative’ sites.

scholarly journals Soil Yeast Communities in Revegetated Post-Mining and Adjacent Native Areas in Central Brazil

2020 ◽  
Vol 8 (8) ◽  
pp. 1116
Author(s):  
Geisianny Augusta Monteiro Moreira ◽  
Helson Mario Martins do Vale
Keyword(s):  
Species Richness ◽  
Soil Microbiome ◽  
Anthropogenic Factors ◽  
Species Accumulation Curves ◽  
Mining Site ◽  
Central Brazil ◽  
Environmental Recovery ◽  
Accumulation Curves ◽  
Ascomycetous Yeasts

Yeasts represent an important component of the soil microbiome. In central Brazil, mining activities are among the main anthropogenic factors that influence the dynamics of the soil microbiota. Few studies have been dedicated to analysis of tropical soil yeast communities, and even fewer have focused on Brazilian hotspots influenced by mining activity. The aim of the current study was to describe soil yeast communities in a post-mining site with revegetated and native areas, along Neotropical Savanna and Atlantic Forest biomes. Yeast communities were described using a culture-based method and estimator-based species accumulation curves, and their associations with environmental characteristics were assessed using multivariate analysis. The results indicate a greater species richness for yeast communities in the revegetated area. We identified 37 species describing 86% of the estimated richness according to Chao2. Ascomycetous yeasts dominated over basidiomycetous species. Candida maltosa was the most frequent species in two phytocenoses. Red-pigmented yeasts were frequent only in the summer. The main soil attributes affecting yeast communities were texture and micronutrients. In conclusion, each phytocenosis showed a particular assemblage of species as a result of local environmental phenomena. The species richness in a Revegetated area points to a possible ecological role of yeast species in environmental recovery. This study provided the first comprehensive inventory of soil yeasts in major phytocenoses in Minas Gerais, Brazil.

scholarly journals Evaluación de métodos no paramétricos para la estimación de riqueza de especies de plantas leñosas en cafetales

2017 ◽  
pp. 7 ◽  
Author(s):  
Ana María López-Gómez ◽  
Guadalupe Williams-Linera
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Woody Plants ◽  
Parametric Models ◽  
Species Accumulation Curves ◽  
Coffee Plantations ◽  
Asymptotic Models ◽  
Accumulation Curves ◽  
Regional Landscape ◽  
Non Parametric

Shade-grown coffee plantations are part of the regional landscape and may contribute to the diversity of woody plants. Tree species richness was evaluated in eight active and abandoned coffee plantations. We used non-parametric (ACE, ICE, Chao 1, Chao 2, Jackknife 1, Jackknife 2, Bootstrap) and asymptotic models (Clench, Linear) to compare observed or sampled richness with estimated richness. The precision of the estimators was evaluated as bias and accuracy through the comparison of estimated richness and true (or total) richness values. Observed richness was 55 tree species in active coffee plantations and 61 species in abandoned plantations. Most species showed a clumped distribution. In no case did species-accumulation curves reach an asymptote. ICE and Chao 2 displayed the best performance. Parametric models were the least precise and Jackknife 2 was the most precise. Non-parametric estimators have disadvantages, but they appear to be appropriate to estimate richness in managed systems such as coffee plantations.

scholarly journals The study of hidden habitats sheds light on poorly known taxa: spiders of the Mesovoid Shallow Substratum

ZooKeys ◽  
2019 ◽  
Vol 841 ◽  
pp. 39-59 ◽  
Author(s):  
Enrique Ledesma ◽  
Alberto Jiménez-Valverde ◽  
Alberto de Castro ◽  
Pablo Aguado-Aranda ◽  
Vicente M. Ortuño
Keyword(s):  
Species Richness ◽  
Iberian Peninsula ◽  
National Park ◽  
Mountain Range ◽  
Species Accumulation Curves ◽  
Distribution Ranges ◽  
Mesovoid Shallow Substratum ◽  
Accumulation Curves ◽  
Richness Estimators ◽  
First Time

The scarce and biased knowledge about the diversity and distribution of Araneae species in the Iberian Peninsula is accentuated in poorly known habitats such as the Mesovoid Shallow Substratum (MSS). The aim of this study was to characterize the spiders inventory of the colluvial MSS of the Sierra de Guadarrama National Park, and to assess the importance of this habitat for the conservation of the taxon. Thirty-three localities were selected across the high peaks of the Guadarrama mountain range and they were sampled for a year using subterranean traps specially designed to capture arthropods in the MSS. Species accumulation curves were built both for the observed species richness and for the non-parametric richness estimators. The literature was reviewed in order to update the distributional maps of the rarest species. Forty-two species were collected, of which four were species new to science. More than half were represented by one or two individuals which caused the accumulation curves to rise slowly and to end without reaching an asymptote. Almost half of the species showed significant increases in their Iberian distribution ranges. Two species were recorded for the first time in the Iberian Peninsula and 32 species were new additions to the spider checklist of the Sierra de Guadarrama National Park.

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