Fuzzy Chorotypes as a Conceptual Tool to Improve Insight into Biogeographic Patterns

Ebola virus is responsible for the fatal Ebola virus disease (EVD). Identifying the distribution area of the Ebola virus is crucial for understanding the risk factors conditioning the emergence of new EVD cases. Existing distribution models have underrepresented the potential contribution that reservoir species and vulnerable species make in sustaining the presence of the virus. In this paper, we map favourable areas for Ebola virus in Africa according to environmental and zoogeographical descriptors, independent of human‐to‐human transmissions. We combine two different biogeographical approaches: analysis of mammalian distribution types (chorotypes), and distribution modelling of the Ebola virus. We first obtain a model defining the distribution of environmentally favourable areas for the presence of Ebola virus. Based on a review of mammal taxa affected by or suspected of exposure to the Ebola virus, we model favourable areas again, this time according to mammalian chorotypes. We then build a combined model in which both the environment and mammalian distributions explain the favourable areas for Ebola virus in the wild. We demonstrate that mammalian biogeography contributes to explaining the distribution of Ebola virus in Africa, although vegetation may also underscore clear limits to the presence of the virus. Our model suggests that the Ebola virus may be even more widespread than previously suspected, given that additional favourable areas are found throughout the coastal areas of West and Central Africa, stretching from Cameroon to Guinea, and extend further East into the East African Lakes region. Our findings show that the most favourable area for the Ebola virus is significantly associated with the presence of the virus in non‐human mammals. Core areas are surrounded by regions of intermediate favourability, in which human infections of unknown source were found. The difference in association between humans and other mammals and the virus may offer further insights on how EVD can spread.

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“…, Olivero et al. , , Romero et al. ), thus fuzzy logic can be easily applied to these concepts (see below).…”

Section: Methodsmentioning

confidence: 99%

Mammalian biogeography and the Ebola virus in Africa

Olivero

Real

et al. 2016

Mammal Review

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“…Nevertheless, the term chorotypes has been widely used when applied to the herpetofauna of certain regions (e.g. Corti et al, 1991Corti et al, , 1997Olivero, Real and Márquez, 2011;Sillero et al, 2009, and reference therein). Our intention here was not to establish a standard classification of biogeographical regions for the European amphibians and reptiles, but to classify species by their distribution similarity using the current available knowledge.…”

Section: Biogeographical Analysesmentioning

confidence: 99%

Updated distribution and biogeography of amphibians and reptiles of Europe

Sillero¹,

Campos²,

et al. 2014

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Abstract. A precise knowledge of the spatial distribution of taxa is essential for decision-making processes in land management and biodiversity conservation, both for present and under future global change scenarios. This is a key base for several scientific disciplines (e.g. macro-ecology, biogeography, evolutionary biology, spatial planning, or environmental impact assessment) that rely on species distribution maps. An atlas summarizing the distribution of European amphibians and reptiles with 50 × 50 km resolution maps based on ca. 85 000 grid records was published by the Societas Europaea Herpetologica (SEH) in 1997. Since then, more detailed species distribution maps covering large parts of Europe became available, while taxonomic progress has led to a plethora of taxonomic changes including new species descriptions. To account for these progresses, we compiled information from different data sources: published in books and websites, ongoing national atlases, personal data kindly provided to the SEH, the 1997 European Atlas, and the Global Biodiversity Information Facility (GBIF). Databases were homogenised, deleting all information except species names and coordinates, projected to the same coordinate system (WGS84) and transformed into a 50 × 50 km grid. The newly compiled database comprises more than 384 000 grid and locality records distributed across 40 countries. We calculated species richness maps as well as maps of Corrected Weighted Endemism and defined species distribution types (i.e. groups of species with similar distribution patterns) by hierarchical cluster analysis using Jaccard's index as association measure. Our analysis serves as a preliminary step towards an interactive, dynamic and online distributed database system (NA2RE system) of the current spatial distribution of European amphibians and reptiles. The NA2RE system will serve as well to monitor potential temporal changes in their distributions. Grid maps of all species are made available along with this paper as a tool for decision-making and conservation-related studies and actions. We also identify taxonomic and geographic gaps of knowledge that need to be filled, and we highlight the need to add temporal and altitudinal data for all records, to allow tracking potential species distribution changes as well as detailed modelling of the impacts of land use and climate change on European amphibians and reptiles.

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“…Regionalizations ideally should account fully for all species and their different evolutionary histories and require very careful interpretation. Promising alternative algorithms (13) and fully resolved and dated phylogenies are being developed (6), but until such conceptual and methodological issues have been resolved, a separation of new realms may seem premature. N2 N3 N4 N5 N6 N7 N8 N9 N10 N11 N12 N13 N14 N15 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 …”

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confidence: 99%

Comment on “An Update of Wallace’s Zoogeographic Regions of the World”

Kreft

Jetz

2013

Science

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Holt et al. (Report, 4 January 2013, p. 74) propose substantial modifications of Wallace's long-standing zoogeographic regions based on clustering of a pairwise similarity matrix of vertebrate assemblages. We worry about their compromised use of phylogenies and show that a fundamental point of their analysis-i.e., the delineation of new realms-is only weakly supported by their results and conceptually flawed. Dividing the world into regions of similar faunistic or floristic composition and shared evolutionary history is a major aim of biogeography. The most prominent regionalization, Wallace's zoogeographic regions (1), has had tremendous influence, but its expert-based nature and lack of quantitative rigor and reproducibility have led to ongoing debates about the number and delineation of regions [reviewed in (2, 3)]. In their Report, Holt et al. (4) follow recently developed methodology and results for mammals (3) and present a quantitative global regionalization that extends to birds and amphibians. Instead of pairwise turnover of species (or genera or families), they used the number of branches in variably resolved phylogenies shared between two assemblages. The integration of global range maps and phylogenetic information to delineate biogeographical regions is promising because it may overcome problems associated with mixed results reported from studies at the species, genus, and family levels (3, 5). However, we believe that the key results of their study-i.e., an integrative delineation of the world's main biogeographical regions and the proposal of five new realms-are largely based on problematic data and methodology, as well as subjective decisions, and thus may have several conceptual flaws.First, we are concerned about the overall poor and taxonomically and geographically disparate resolution of the tree topologies invoked. These were single trees in which only 40 to 60% of species were resolved, meaning that species' contributions to the regionalization were highly nonuniform and, in some cases, very minor.Second, only counts of branches, not their actual lengths, were used for quantifying dissimilarity. This will in some cases equate species 20 million years old with those just 20,000 years old and ignores considerable differences in the ages of clades (e.g., amphibians versus birds) and regions. The authors suggest that in mammals, such differences, or even using just species' taxonomic separation instead, would not affect the existence and location of zoogeographic regions. We feel that this casts doubt, in this implementation, on the rigor and relevance of the "phylogenetic" method. New approaches are arising that account for all species in a single quantitative framework and that estimate branch lengths and uncertainty (6, 7). In the midst of such major phylogenetic advances for vertebrates, we support caution over a rush in updating Wallace's regions.Third, the authors propose the Saharo-Arabian, Sino-Japanese, and Panamanian as new "realms," even though they do not match their criterion of ...

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Fuzzy Chorotypes as a Conceptual Tool to Improve Insight into Biogeographic Patterns

Cited by 46 publications

References 63 publications

Mammalian biogeography and the Ebola virus in Africa

Mammalian biogeography and the Ebola virus in Africa

Updated distribution and biogeography of amphibians and reptiles of Europe

Comment on “An Update of Wallace’s Zoogeographic Regions of the World”

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