Geographical sampling bias in a large distributional database and its effects on species richness-environment models

2013 ◽  
Vol 40 (8) ◽  
pp. 1415-1426 ◽  
Author(s):  
Wenjing Yang ◽  
Keping Ma ◽  
Holger Kreft
Keyword(s):  
Species Richness ◽  
Sampling Bias

scholarly journals Mapping species richness using opportunistic samples: a case study on ground-floor bryophyte species richness in the Belgian province of Limburg

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thomas Neyens ◽  
Peter J. Diggle ◽  
Christel Faes ◽  
Natalie Beenaerts ◽  
Tom Artois ◽  
...  
Keyword(s):  
Species Richness ◽  
Process Model ◽  
Cost Effective ◽  
Sampling Bias ◽  
Parameter Estimates ◽  
Multiple Sources ◽  
Ground Floor ◽  
Sampling Process ◽  
Ecological Predictors ◽  
Geostatistical Models

AbstractIn species richness studies, citizen-science surveys where participants make individual decisions regarding sampling strategies provide a cost-effective approach to collect a large amount of data. However, it is unclear to what extent the bias inherent to opportunistically collected samples may invalidate our inferences. Here, we compare spatial predictions of forest ground-floor bryophyte species richness in Limburg (Belgium), based on crowd- and expert-sourced data, where the latter are collected by adhering to a rigorous geographical randomisation and data collection protocol. We develop a log-Gaussian Cox process model to analyse the opportunistic sampling process of the crowd-sourced data and assess its sampling bias. We then fit two geostatistical Poisson models to both data-sets and compare the parameter estimates and species richness predictions. We find that the citizens had a higher propensity for locations that were close to their homes and environmentally more valuable. The estimated effects of ecological predictors and spatial species richness predictions differ strongly between the two geostatistical models. Unknown inconsistencies in the sampling process, such as unreported observer’s effort, and the lack of a hypothesis-driven study protocol can lead to the occurrence of multiple sources of sampling bias, making it difficult, if not impossible, to provide reliable inferences.

scholarly journals Species packing and the latitudinal gradient in local beta-diversity

2020 ◽  
Author(s):  
Ke Cao ◽  
Richard Condit ◽  
Xiangcheng Mi ◽  
Lei Chen ◽  
Haibao Ren ◽  
...  
Keyword(s):  
Species Richness ◽  
Tropical Forests ◽  
Beta Diversity ◽  
Latitudinal Gradient ◽  
Sampling Bias ◽  
Small Samples ◽  
Gamma Diversity ◽  
Species Packing ◽  
High Gamma ◽  
Declining Species

AbstractThe latitudinal gradient of declining species richness at higher latitudes is among the most fundamental patterns in ecology. However, whether changes in species composition across space (beta-diversity) contribute to this global gradient of species richness remains debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in high gamma-diversity areas to inflate measures of beta-diversity. We provide here a rigorous test, comparing species-packing and local heterogeneity across a latitudinal gradient in tree species richness in Asia, using beta-diversity metrics that correct the gamma-diversity and sampling bias. Our data include 21 large forest plots across a wide environmental gradient in East Asia. We demonstrate that local beta-diversity increases with topographic heterogeneity, but after accounting for this and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate, contributing to the latitudinal gradient of species richness. This supports the hypothesis of tighter species packing and larger niche space in tropical forests while demonstrating the importance of local processes in controlling beta-diversity.

scholarly journals Latitudinal gradients in body size in marine tardigrades

2019 ◽  
Vol 188 (3) ◽  
pp. 820-838
Author(s):  
Paul J Bartels ◽  
Diego Fontaneto ◽  
Milena Roszkowska ◽  
Diane R Nelson ◽  
Łukasz Kaczmarek
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Net Primary Productivity ◽  
Linear Models ◽  
Generalized Least Squares ◽  
Sampling Bias ◽  
Latitudinal Gradients ◽  
Biased Sampling ◽  
Sampling Effort ◽  
Latitudinal Pattern

Abstract Homeotherms and many poikilotherms display a positive relationship between body size and latitude, but this has rarely been investigated in microscopic animals. We analysed all published records of marine Tardigrada to address whether microscopic marine invertebrates have similar ecogeographical patterns to macroscopic animals. The data were analysed using spatially explicit generalized least squares models and linear models. We looked for latitudinal patterns in body size and species richness, testing for sampling bias and phylogenetic constraints. No latitudinal pattern was detected for species richness, and sampling bias was the strongest correlate of species richness. A hump-shaped increase in median body size with latitude was found, and the effect remained significant for the Northern Hemisphere but not for the Southern. The most significant effect supporting the latitudinal gradient was on minimum body size, with smaller species disappearing at higher latitudes. Our results suggest that biogeographical signals were observed for body size, albeit difficult to detect in poorly studied groups because of swamping from biased sampling effort and from low sample size. We did not find a significant correlation with the latitudinal pattern of body size and ecologically relevant net primary productivity.

scholarly journals How many dinosaur species were there? Fossil bias and true richness estimated using a Poisson sampling model (TRiPS)

2015 ◽  
Author(s):  
Jostein Starrfelt ◽  
Lee Hsiang Liow
Keyword(s):  
Species Richness ◽  
Fossil Record ◽  
Biological Diversity ◽  
Temporal Dynamics ◽  
Sampling Bias ◽  
Biased Sampling ◽  
Poisson Sampling ◽  
The Past ◽  
Past Life ◽  
Source Of Information

The fossil record is a rich source of information about biological diversity in the past. However, the fossil record is not only incomplete but has inherent biases due to geological, physical, chemical and biological factors. Our knowledge of past life is also biased because of differences in academic and amateur interests and sampling efforts. As a result, not all individuals or species that lived in the past are equally likely to be discovered at any point in time or space. To reconstruct temporal dynamics of diversity using the fossil record, biased sampling must be explicitly taken into account. Here, we introduce an approach that utilizes the variation in the number of times each species is observed in the fossil record to estimate both sampling bias and true richness. We term our technique TRiPS (True Richness estimated using a Poisson Sampling model) and explore its robustness to violation of its assumptions via simulations. We then venture to estimate sampling bias and absolute species richness of dinosaurs in the geological stages of the Mesozoic. Using TRiPS, we estimate that 1936 (1543-2468) species of dinosaurs roamed the Earth during the Mesozoic. We also present improved estimates of species richness trajectories of the three major dinosaur clades; the sauropodomorphs, ornithischians and theropods, casting doubt on the Jurassic-Cretaceous extinction event and demonstrating that all dinosaur groups are subject to considerable sampling bias throughout the Mesozoic.

scholarly journals Endemicity and Community Composition of Marine Species along the NW Pacific and Adjacent Arctic Ocean

2019 ◽  
Vol 3 ◽  
Author(s):  
Hanieh Saeedi ◽  
Marianna Simoes ◽  
Angelika Brandt
Keyword(s):  
Species Richness ◽  
Pacific Ocean ◽  
Arctic Ocean ◽  
Shallow Water ◽  
Community Composition ◽  
Deep Sea ◽  
Sampling Bias ◽  
The Arctic ◽  
Philippine Sea ◽  
The Arctic Ocean

The Northwestern (NW) Pacific Ocean lies in one of the most productive, speciose, and diverse regions of the World Ocean, and includes several shallow-water oceanic islands and deep-sea basins of varying depth, hydrology, and degree of isolation. The adjacent Arctic Ocean areas include the northern Bering and southern Chukchi Seas of the Arctic Ocean with short food chains and shallow depths characterizing high productivity areas. Despite its magnitude and relevance, characterization of species diversity and community composition patterns in the NW Pacific Ocean remains poorly explored and largely unknown. Here we attempt to discover how geographic boundaries and depth shape current community assemblages and delimit species distribution ranges and richness using open access data. We also show how endemicity and community composition vary between tropical and temperate NW Pacific and the adjacent Arctic Ocean considering sampling bias. The Eastern Philippine Sea was the hotspot of species richness in the NW Pacific and its adjacent Arctic Ocean even when accounting for sampling bias. The lowest species richness was observed in Papau. Despite high species richness in the Eastern Philippine Sea, the Yellow Sea and Gulf of Tonkin had the highest endemicity rates (ca. 60%) among all other ecoregions. Endemicity ranged 20–40% across 19 ecoregions. Chordata, Arthropoda, and Mollusca contributed more than 50% to the total community composition in the NW Pacific where as Arthropoda, Annelida, and Mollusca were the dominant taxa shaping ca. 82% of the Arctic Ocean community. Pelagic species richness was higher than the benthic one in both shallow-water and deep-sea regions of the NW Pacific Ocean. However, in the shallow and deep Arctic Ocean, most of the taxa were benthic excluding the deep Kara Sea where pelagic deep-sea species dominated the whole community. Two significantly distinctive clusters (North and South clusters) were classified based on species richness similarity analysis in this area including ecoregions of the (1) Arctic Ocean and North NW Pacific, and (2) Mid to South NW Pacific.

Biogeography of polychaete worms (Annelida) of the world

2021 ◽  
Vol 657 ◽  
pp. 147-159
Author(s):  
J Pamungkas ◽  
CJ Glasby ◽  
MJ Costello
Keyword(s):  
Species Richness ◽  
Sampling Bias ◽  
Distribution Patterns ◽  
Natural Phenomenon ◽  
Global Biodiversity Information Facility ◽  
Sea Temperature ◽  
Polychaete Species ◽  
The North ◽  
The World ◽  
Biogeographic Regions

The global biogeography of polychaete worms has never been assessed previously. In the present study, we studied the world distribution patterns of polychaetes based on datasets obtained from the Global Biodiversity Information Facility, the Ocean Biogeographic Information System and our recently published checklist of Indonesian polychaete species. Polychaete biogeographic regions were visualized using ‘Infomap Bioregions’, and the latitudinal species richness gradient of the animals was examined using 3 metrics, i.e. alpha, gamma and estimated species richness (the last metric was adjusted for sampling bias). We identified 11 major polychaete biogeographic regions. The North Atlantic, Australia and Indonesia were the top 3 species-rich biogeographic regions in the world. The total number of polychaete species was higher in the southern hemisphere (~2100 species, 67 families) than in the northern hemisphere (~1800 species, 75 families) despite significantly more data in the latter (>500000 records compared to >26000 records). Contrary to the classical idea of a unimodal distribution pattern, the latitudinal gradient of polychaetes was generally bimodal with a pronounced dip north of the Equator (15°N). We suggest that the slightly higher peak of species richness in the southern (30°S) than in the northern (60°N) hemisphere reflects higher southern endemicities. These patterns are unlikely to be due to sampling bias but rather represent a natural phenomenon, and we found them most significantly correlated with sea temperature.

Usefulness of funnel traps in catching small reptiles and mammals, with comments on the effectiveness of the alternatives

2007 ◽  
Vol 34 (6) ◽  
pp. 491 ◽  
Author(s):  
Graham G. Thompson ◽  
Scott A. Thompson
Keyword(s):  
Species Richness ◽  
Environmental Impact ◽  
Small Mammals ◽  
Relative Abundance ◽  
Western Australia ◽  
Sampling Bias ◽  
Terrestrial Vertebrates ◽  
Environmental Impact Assessments

Funnel traps were used in conjunction with pit traps (PVC buckets and pipes), Elliott traps and cage traps at 10 sites in southern Western Australia to examine sampling bias of trap types. Funnel traps seldom catch small mammals but catch more of the medium-sized and large terrestrial, diurnal snakes and some of the widely foraging, medium-sized skinks, medium-sized dragon lizards and arboreal geckos that climb out of PVC pit traps. For pit traps, buckets catch more reptiles, particularly smaller ones, than pipes. However, pipes catch more mammals than buckets. Elliott traps catch the same suite of small mammals as pipes plus some of the large, trappable species, such as Rattus spp. Cage traps are useful for trapping Tiliqua spp. and medium-sized mammals such as possums and bandicoots that are unlikely to be caught in pit and funnel traps. Funnel traps, pit traps and cage traps should be used in surveys of small terrestrial vertebrates to determine species richness and relative abundance in Western Australia and probably elsewhere. However, as cage traps are mostly useful for catching Tiliqua spp. and medium-sized mammals, they need only be used in faunal surveys undertaken for environmental impact assessments specifically targeting these species.

Evaluating the sampling bias in pattern of subterranean species richness: combining approaches

2010 ◽  
Vol 19 (11) ◽  
pp. 3035-3048 ◽  
Author(s):  
Maja Zagmajster ◽  
David C. Culver ◽  
Mary C. Christman ◽  
Boris Sket
Keyword(s):  
Species Richness ◽  
Sampling Bias ◽  
Subterranean Species
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