Biogeographic Classification Research Articles

Using floristic data to shed light on the origin of flora in the poorly studied common cypress habitats of Northern Iran

Despite the ecological importance, there is a large knowledge gap on different habitat types of the Hyrcanian World Heritage. The Hyrcanian Common Cypress Habitats (HCCHs), the easternmost part of the Common Cypress habitats in the world, are one of these habitat types. HCCHs are understudied and threatened by a variety of anthropogenic disturbances. In the current study, synthesizing the floristic data of all HCCHs, we compared the species composition of HCCHs to 20 habitats from the Hyrcanian, Irano-Turanian, and Mediterranean regions. Also, we candidate the HCCH with the highest conservation priority by calculating the phylogenetic richness of HCCHs. The ordination analysis results showed that the HCCHs form a distinct group from the three regions. Thus, we found that the HCCHs have a unique floristic composition. The geographical distance had a weak effect on the grouping (Procrustes Sum of Squares = 0.886 and p-value < 0.001). We also detected that the phylogenetic richness of the HCCHs is highest in the Golestan National Park which is the easternmost habitat of HCCHs. Therefore, this park had the most conservation value. Our results provide new insights into the floristic composition and conservation status of the Hyrcanian World Heritage. We conclude that the bioclimatic classifications might be a better predictor of floristic compositions than biogeographical classifications. Based on the observation of Hyrcanian habitats with intermediate floristic composition, it is necessary to reconsider the biogeographical classifications of the region. Our findings are useful for developing management strategies for HCCHs.

Quantifying the probability of a successful marine bioinvasion due to source-destination risk factors.

The increasing spread of marine non-indigenous species (NIS) due to the growth in global shipping traffic is causing widespread concern for the ecological and economic impacts of marine bioinvasions. Risk management authorities need tools to identify pathways and source regions of priority concern to better target efforts for preventing NIS introduction. The probability of a successful NIS introduction is affected by the likelihood that a marine species entrained in a transport vector will survive the voyage between origin and destination locations and establish an independently reproducing population at the destination. Three important risk factors are voyage duration, range of environmental conditions encountered during transit and environmental similarity between origin and destination. In this study, we aimed for a globally comprehensive approach to assembling quantifications of source-destination risk factors from every potential origin to every potential destination. To derive estimates of voyage-related marine biosecurity risk, we used computer-simulated vessel paths between pairs of ecoprovinces in the Marine Ecoregions Of the World biogeographic classification system. We used the physical length of each path to calculate voyage duration risk and the cross-latitudinal extent of the path to calculate voyage path risk. Environmental similarity risk was based on comparing annual average sea surface temperature and salinity within each ecoprovince to those of other ecoprovinces. We derived three separate sets of risk quantifications, one each for voyage duration, voyage path and environmental similarity. Our quantifications can be applied to studies that require source-destination risk estimates. They can be used separately or combined, depending on the importance of the types of source-destination risks that might be relevant to particular scientific or risk management questions or applications.

Chilean bee diversity: Contrasting patterns of species and phylogenetic turnover along a large‐scale ecological gradient

AbstractChile's isolation and varied climates have driven the evolution of a unique biodiversity with a high degree of endemism. As a result, Chile encompasses diverse environments, including the Mediterranean‐type ecosystem, a global biodiversity hotspot. These environments are currently threatened by anthropogenic land use change impacting the integrity of local biomes and associated species. This area is the most intensively sampled in the country with high endemicity of native bee species. Characterizing habitat requirements of bees is a pressing priority to safeguard these insects and the ecosystem services they provide. We investigated broadscale patterns of bee (Hymenoptera: Apoidea: Anthophila) diversity using newly accessible expert‐validated datasets comprising digitized specimen records from Chilean and US collections, and novel expert‐validated‐type specimen data for the bees of Chile. We used a generalized dissimilarity modeling (GDM) approach to explore both compositional and phylogenetic β‐diversity patterns across latitudinal, altitudinal, climate, and habitat gradients in well‐sampled bee assemblages in Central Chile. Using the GDM measures of increasing compositional and environmental dissimilarity, we categorized and compared the most important drivers of these patterns and used them to classify “wild bee ecoregions” (WBEs) representing unique assemblages. Turnover of bee assemblages was explained primarily by latitudinal variation (proxy for climate) from south to north in Chile. However, temperature variations, precipitation, and the presence of bare soil also significantly explained turnover in bee assemblages. In comparison, we observed less turnover in phylogenetic biodiversity corresponding to spatial gradients. We identified six de novo ecoregions (WBEs), all with distinct taxa, endemic lineages, and representative species. The WBEs represent distinct spatial classifications but have similarities to existing biogeographical classifications, ecosystems, and bioclimatic zones. This approach establishes the baseline needed to prioritize bee species conservation efforts across this global biodiversity hotspot. We discuss the novelty of this classification considering previous biogeographical characterizations and their relevance in assessing conservation priorities for bee conservation. We argue that Chile's WBEs highlight areas in need of funding for bee species surveys and description, distribution mapping, and strengthening of conservation policies.

Benthic biogeographic patterns on the deep Brazilian margin.

The Brazilian continental margin (BCM) extends from the Tropical to the Subtropical Atlantic Ocean, with much of its seafloor within deep waters, supporting rich geomorphological features and under wide productivity gradients. Deep-sea biogeographic boundaries on the BCM have been limited to studies that used water mass and salinity properties of deep-water masses, partly as a result of historical under sampling and a lack of consolidation of available biological and ecological datasets. The aim of this study was to consolidate benthic assemblage datasets and test current oceanographic biogeographical deep-sea boundaries (200-5,000 m) using available faunal distributions. We retrieved over 4,000 benthic data records from open-access databases and used cluster analysis to examine assemblage distributions against the deep-sea biogeographical classification scheme from Watling et al. (2013). Starting from the assumption that vertical and horizontal distribution patterns can vary regionally, we test other schemes incorporating latitudinal and water masses stratification within the Brazilian margin. As expected, the classification scheme based on benthic biodiversity is in overall agreement with the general boundaries proposed by Watling et al. (2013). However, our analysis allowed much refinement in the former boundaries, and here we propose the use of two biogeographic realms, two provinces and seven bathyal ecoregions (200-3,500 m), and three abyssal provinces (>3,500 m) along the BCM. The main driver for these units seems to be latitudinal gradients as well as water mass characteristics such as temperature. Our study provides a significant improvement of benthic biogeographic ranges along the Brazilian continental margin allowing a more detailed recognition of its biodiversity and ecological value, and also supports the needed spatial management for industrial activities occurring in its deep waters.

Regionalization of Cacao (Theobroma cacao L.) in Colombia

A detailed description and up to date biogeographic regionalization of cultivated cacao (Theobroma cacao L.) are lacking in Colombia. Here we propose a new biogeographical regionalization of cultivated cacao for Colombia. We used spatial partitioning, geospatial mapping of macro/microclimate variables and a hierarchical area taxonomy classification to describe, define and propose the biogeographical regions of cultivated cacao. The cacao regions were identified from distributions of 4,974 cocoa producing farms across Colombia. Our proposed regionalization comprises four regions (north-eastern, north-western, south-western, east), 31 sub-regions and 54 provinces. Solar radiation, precipitation, and soil temperature seasonality best explained the biogeographical regions. Rivers networks helped explain the differences at the sub-regional and provinces level. Our results indicate that biogeography is a strong indicator of cacao's agricultural expansion across the different growing regions in Colombia. This up-to-date biogeographical classification could be a useful tool for agricultural planning of cacao in Colombia. Particularly, the baseline information provided might be of use on the development of denominations of origin for cacao.

Biogeographical Classification of the Global Ocean From BGC-Argo Floats.

Biogeographical classifications of the global ocean generalize spatiotemporal trends in species or biomass distributions across discrete ocean biomes or provinces. These classifications are generally based on a combination of remote‐sensed proxies of phytoplankton biomass and global climatologies of biogeochemical or physical parameters. However, these approaches are limited in their capacity to account for subsurface variability in these parameters. The deployment of autonomous profiling floats in the Biogeochemical Argo network over the last decade has greatly increased global coverage of subsurface measurements of bio‐optical proxies for phytoplankton biomass and physiology. In this study, we used empirical orthogonal function analysis to identify the main components of variability in a global data set of 422 annual time series of Chlorophyll a fluorescence and optical backscatter profiles. Applying cluster analysis to these results, we identified six biomes within the global ocean: two high‐latitude biomes capturing summer bloom dynamics in the North Atlantic and Southern Ocean and four mid‐ and low‐latitude biomes characterized by variability in the depth and frequency of deep chlorophyll maximum formation. We report the distribution of these biomes along with associated trends in biogeochemical and physicochemical environmental parameters. Our results demonstrate light and nutrients to explain most variability in phytoplankton distributions for all biomes, while highlighting a global inverse relationship between particle stocks in the euphotic zone and transfer efficiency into the mesopelagic zone. In addition to partitioning seasonal variability in vertical phytoplankton distributions at the global scale, our results provide a potentially novel biogeographical classification of the global ocean.

Population Structure of Chum Salmon of the Russian Far East: Biogeographic Classification, Genetic Differentiation, and Ecogeographic Units of the Species

Population Structure of Chum Salmon of the Russian Far East: Biogeographic Classification, Genetic Differentiation, and Ecogeographic Units of the Species

Changes in Mangrove Carbon Stocks and Exposure to Sea Level Rise (SLR) under Future Climate Scenarios

Mangrove ecosystems are threatened by a variety of anthropogenic changes, including climate change. The main aim of this research is to quantify the spatial variation in the different mangrove carbon stocks, aboveground carbon (AGC), belowground carbon (BGC), and soil carbon (SOC), under future climate scenarios. Additionally, we sought to identify the magnitude of sea-level rise (SLR) exposure with the view of identifying the mangrove regions most likely to face elevated inundation. Different representative concentration pathways (RCPs) ranging from the most optimistic (RCP 2.6) to medium emissions (RCP 4.5) and the most pessimistic (RCP 8.5) were considered for 2070. We used the Marine Ecoregions of the World (MEOW), a biogeographical classification of coastal ecosystems, to quantify the variation in future carbon stocks at a regional scale and identify areas of potential carbon stock losses and gains. Here, we showed that the mangroves of Central and Western Indo-Pacific islands (Andamans, Papua New Guinea, and Vanuatu), the west African coast, and northeastern South America will be the worst hit and are projected to affect all three carbon stocks under all future scenarios. For instance, the Andaman ecoregion is projected to have an 11–25% decline in SOC accumulation, while the Western Indo-Pacific realm is projected to undergo the sharpest declines, ranging from 10% to 12% under all three scenarios. Examples of these areas are those in Amazonia and the eastern part of South Asia (such as in the Northern Bay of Bengal ecoregion). Based on these findings, conservation management of mangroves can be conducted.

Occurrence of pathogenic microorganisms in small drinking-water systems in Costa Rica

This study describes the quality of drinking water sampled over 2 years (2018 and 2019) from 20 ASADAS (Spanish acronym for Administrative Associations for Water and Sewer Systems) in Costa Rica. The analysis included Rotavirus (RV), somatic coliphages, fecal coliforms, and Escherichia coli. The ASADAS were categorized into three regions as temperate rainy (region 1), tropical rainy (region 2), and tropical rainy and dry (region 3) according to biogeographic classification. The concentrations of fecal coliforms and E. coli were higher in samples from surface water sources from the ASADAS in region 3 compared to regions 1 and 2. RV-positive samples (24/296) were detected in drinking-water samples from regions 2 and 3 during dry and transition seasons, with higher concentrations more frequently in the dry season. In addition, somatic coliphages were detected in samples from the three regions, with higher concentrations in region 2. Furthermore, a statistically significant relationship was found between somatic coliphages and diarrheal cases, classified as outbreaks or alerts in the region. Thus, the results confirmed that somatic coliphages are a good indicator of the presence of diarrhea cases in a specific region.

Biogeographical classification of Austria based on hierarchical cluster analysis of vascular plant distributions

Biogeographical classification of Austria based on hierarchical cluster analysis of vascular plant distributions

The distribution of offshore benthic molluscs provides new insight into South Africa's marine biogeography

South African marine biogeography has received a great deal of attention in the past. However, offshore biogeographic breaks are based on abiotic variables or specialist opinion rather than data-driven approaches. Here we investigate biogeographic breaks based on the distribution of offshore marine benthic molluscs collected during the Natal Museum Dredging Programme (1981–1997) along the coast of South Africa, between the South East Atlantic and South West Indian Oceans. Spatially constrained (depth, latitude and longitude) cluster analyses were applied to three resemblance measures; the Jaccard coefficient, popular in biogeographic studies, and gamma+ and theta+ coefficients, where taxonomic relatedness is considered when comparing sites. We used these resemblances to 1) find the most consistent biogeographic breaks and 2) compare the results of different measures to better understand the patterns and possible processes involved in the biogeographical classification. Although there were differences in the overall results from the three resemblance measures, they produced comparable findings at depths shallower than 80 m. Our data-driven approach indicated that the biogeographic break between the warm-temperate and sub-tropical assemblages was 140 km north of the current inshore break. The break between the sub-tropical and tropical mollusc assemblages agreed more closely with the present Ecoregions. Compared to Jaccard, where relatedness is not considered, gamma+ and theta+ results revealed a more substantial depth effect, and samples collected in the same depth range were more closely related and shared a more recent evolutionary history than geographically close samples from different depths. Furthermore, assemblages found deeper than ∼80 m demonstrated greater diversity in terms of relatedness, an essential consideration in marine spatial planning and consequent designation of protected areas. This study reveals the importance of including in-situ data and interspecies relationships in future marine spatial planning to ensure that these evolutionary rich animal communities are considered adequately.

Maputo Special Reserve and dung beetle conservation in the heterogeneous landscape of the Maputaland Centre of Endemism

Background: Maputo Special Reserve (MSR) in Mozambique lays within the Maputaland Centre of Endemism (MCE) and protects the biota of a habitat mosaic dominated by coastal dune forest and inland sand forest patches of different sizes surrounded by natural grassland. Objectives: To determine the importance of woody versus grassland vegetation for supporting endemic east coast versus widespread savanna dung beetles in the MCE in the face of increased accessibility and exploitation of woody vegetation in southern Mozambique, especially by charcoal burners.Method: We used general linear mixed models, additive partitioning of diversity and ordination to analyse species abundance and occurrence across a mosaic of three major habitats in the MSR (grassland, sand and dune forest).Results: High compositional heterogeneity was found between habitat types and study sites so that beta diversity was mostly higher than alpha diversity. Three distinct scarabaeine dung beetle assemblages defined from ordination were largely centred on the three habitat types. Out of a total of 61 species, greater numbers were associated with grassland (38) than sand (17) and dune forest (6) although abundance was greater in both dune forest and grassland than in sand forest. Biogeographical classification indicated that &gt;40% of the species are endemic to the east coast of southern Africa with the remainder centred in adjacent savanna. Endemic east coast species were well represented in both forest (15) and grassland (11). Savanna species were better represented in grassland (27) than forest (8). Proportions of grassland species and their abundance declined across increasing patch sizes of sand forest becoming lowest in dune forest.Conclusions: Conservation of endemic, east coast dung beetle species requires the preservation of both natural grassland and sizeable patches of forest in an undisturbed habitat mosaic. As the east coastal system is relatively small in extent with the MCE widely transformed in South Africa, the MSR is an important contributor to regional conservation of endemic species.

Data‐driven bioregionalization: A seascape‐scale study of macrobenthic communities in the Eurasian Arctic

AbstractAimWe conduct the first model‐based assessment of the biogeographical subdivision of Eurasian Arctic seas to (1) delineate spatial distribution and boundaries of macrobenthic communities on a seascape level; (2) assess the significance of environmental drivers of macrobenthic community structures; (3) compare our modelling results to historical biogeographical classifications; and (4) couple the model to climate scenarios of environmental changes to project potential shifts in the distribution and composition of macrobenthic communities by 2100.LocationEurasian Arctic seas, in particular Barents, Kara and Laptev Seas.Taxon169 species of macrobenthic fauna; most common taxa are Polychaeta (85 species), Malacostraca (30 species), Bivalvia (26 species) and Gastropoda (10 species).MethodsWe employed the Region of Common Profile (RCP) approach to assess the bioregionalization patterns of Eurasian Arctic seafloor communities. The RCP approach allows the identification of seascape‐scale distribution patterns by simultaneously considering biotic and environmental data within one modelling step.ResultsFour RCPs were identified within the Eurasian Arctic. The results showed that water depth, sea‐ice cover, bottom‐water temperature and salinity, proportion of fine sediments, particulate organic carbon (POC) and depth of the euphotic zone were among the most important driving variables of macrobenthos communities. The projections, driven by the climate‐change scenarios, suggested a general north‐eastward shift of the RCPs over the 21st century, mainly correlated with retreating sea‐ice and increasing sea‐bottom temperature.Main conclusionsThe identified RCPs largely match the previously reported large‐scale distribution patterns of macrobenthic communities in Eurasian Arctic seas. The spatio‐temporal dynamics of RCPs are in agreement with local long‐term observation data on macrobenthic resilience/vulnerability in the studied region. The representation of the ecoregions and biotas in a probabilistic form, together with quantitative assessment of potential climate‐driven changes, will help to adequately consider macrobenthic biodiversity dynamics in the development of science‐based conservation measures.

The biomes of Western Australia: a vegetation-based approach using the zonality/ azonality conceptual framework

ABSTRACT Vegetation patterns of are the result of environmental drivers operating across a range of ecological and evolutionary scale. Those vegetation patterns at global and continental scales underpin the existence of large-scale functional entities called biomes. Traditionally, terrestrial biomes are recognised and distinguished by way of physiognomic traits thought to reflect the action of selective filters such as climate or disturbance (fire, grazing). This approach is well suited to recognising zonal biomes; it fails, however, to account for the role of other drivers such as soil and hydrology, potentially leading to over simplified representations of the biome patterns in ecologically complex regions such as Western Australia. It is, therefore, of vital importance to consider these patterns and processes and recognise the azonal biomes as well. Using a previously published physiognomic map of the vegetation of Western Australia, we adopted a bottom-up approach to translate the vegetation classification categories into a new biome classification of Western Australia that would more accurately account for the zonal and azonal structures recorded across the landscape. Five continental zonal biomes (Australian Eucalyptus Savanna, Australian Hummock Grassland, Mulga Shrubland, Australian Temperate Woodland, Australian Oceanic Temperate Forest) and one relict biome (Australian Vine Thicket) were identified. We further distinguished 34 types of azonal biomes, including three new ones: argillobiome, duplo-pedobiome and metallobiome. Predictive modelling (using Classification and Regression Trees) was used to define the potential extent of zonal biomes, with the model returning an overall accuracy of 90%. This study shows that a bottom-up approach based on vegetation maps can be used as an effective approximation for defining a robust classification of biome patterns. The predicted zonal biomes correspond well with existing traditional biogeographic classifications, yet some residual climatic discordance warrants further study.

&lt;p&gt;&lt;strong&gt;Biogeographical regionalisation of Colombia: a revised area taxonomy&lt;/strong&gt;&lt;/p&gt;

This study proposes a biogeographical regionalisation of Colombia based on geospatial analyses of plant species turnover and a revised area taxonomy. The spatial patterns of species turnover are calculated for 20,342 plant species in continental Colombia with distributions estimated from 271,568 georeferenced records aggregated to 414 (~50 km) grid cells across Colombia. The proposed biogeographic regions are defined by applying an agglomerative cluster analysis using a matrix of pairwise Simpson’s beta (bsim) dissimilarity values. Three main centres of species richness and 25 areas of endemism were identified across Colombia, complementing the definition of regionalisation. Biogeographical regionalisation comprises two dominions (Pacific and Boreal Brazilian), six provinces (Chocó-Darién, Guajira, Magdalena, Paramo, Sabana and Imerí) and thirty-five districts. The revised area taxonomy provides an updated and objective biogeographical classification for Colombia and is the first biogeographic regionalisation exclusively based on the taxic distributional overlap of Colombia´s land plants.

Upper Bathyal Pacific Ocean biogeographic provinces from octocoral distributions

Biogeographical classification schemes such as the Marine Ecoregions of the World (MEOW) have been developed for continental shelf depths. The lack of faunal data in the deep sea has led to the development of biogeographical units based on oceanographic characteristics. The aim of this study was to propose biogeographical schemes for the Upper Bathyal (200–1000 m) across the Pacific Ocean using octocoral distributions. We retrieved over 200 000 octocoral data records from the Deep Sea Coral Data Portal (DSCDP), Ocean Biogeographic Information System (OBIS), Tropical Deep-Sea Benthos program (French National Museum of Natural History), Queensland Museum from the CIDARIS expeditions, and records retrieved from the Siboga expedition reports. We used cluster analysis to examine octocoral distributions against four different biogeographical classification schemes. The classification schemes produced mostly concordant patterns with three major faunal distribution barriers: the North Pacific Current isolates the subarctic units by creating a steep temperature gradient; the Subantarctic Front separates the Subantarctic from the rest of the Pacific; and the East Pacific Barrier separates the East Pacific from the Central and West Pacific. Two other smaller but distinct provinces are the Indo-Pacific where Lower Bathyal genera are found in the Upper Bathyal, and Torres Strait/Coral Sea characterised by mesophotic genera. We propose 12 biogeographic provinces across the Pacific Ocean Upper Bathyal region from 200 to 1000 m depth based on octocoral distributions. The main driver for these units seems to be temperature, a defining feature of water masses. These units could potentially be subdivided into smaller regions based on habitat. Additionally, the clustering of Ecological Marine Units (EMUs) provides evidence that the Upper Bathyal should in certain regions be divided vertically into two depth zones based on water masses.

A review of transition zones in biogeographical classification

AbstractTransition zones are problematic in biogeographical classification as they represent artificial biotic areas. A review of transition zones into existing biogeographical classifications shows conflicting area taxonomies. While many authors consider transition zones as overlap zones or areas of biotic mixing, only a few have considered excluding them from biogeographical classification all together. One way of incorporating transition zones into a natural classification is by treating them as artefacts of geographically overlapping temporally disjunct biotic areas. In doing so, geographically overlapping biotic areas may occupy the same space but have different boundaries and histories. Temporally disjunct areas do form natural hierarchical classifications, as seen in the paleobiogeographical literature. A revision of each transition zone will determine whether they are artificial areas, areas within their own right or potentially geographically overlapping temporally disjunct regions.

Caspian Sea environmental variables: an extension of the Bio-ORACLE ocean data set.

The Caspian Sea hosts unique native and endemic faunas. However, it is also a source and sink of invasive alien species (IAS), with some listed among the worst 100 invasive species by the IUCN. A common approach to study biodiversity and biogeographic patterns or to predict the invasive potential of species is the application of ecological niche models and species distribution models. These are statistical methods using spatially gridded environmental data and species occurrence information. As the Caspian Sea is not connected to the world's oceans, spatially gridded environmental data for the Caspian Sea are not available in the widely used Bio-ORACLE marine data set. To address this issue, we compiled 28 ecologically relevant spatially gridded environmental variables using Kriging interpolation of point data to model minimum, maximum, mean, and range of temperature, salinity, and dissolved oxygen for the surface and benthic zones of the Caspian Sea. Data were retrieved from the World Ocean Database. Additionally, we utilized raster statistics to create surface layers of maximum, mean, minimum, and range of chlorophyll a from remotely sensed data. We developed these environmental variables as they were previously confirmed to be relevant for the biogeographical classification of the Caspian Sea. To allow projections of models across the world's oceans into the Caspian Sea (and vice versa), we matched our raster dimensions with those of the Bio-ORACLE data set. Our extension of the Bio-ORACLE data set with data from the Caspian Sea provides an important basis for the monitoring and evaluation of suitable habitats for native species as well as predicting the invasive potential of Caspian Sea species into world oceans. Please cite this Data Paper and the associated Figshare data set if the data are used in publications.

A biogeographical and ecological classification of orchids in Turkey

A biogeographical and ecological classification of orchids in Turkey

Bioregionalization approaches for conservation: methods, biases, and their implications for Australian biodiversity

Biogeographic classification schemes have been developed to prioritize biodiversity conservation efforts at large scales, but their efficacy remains understudied. Here we develop a systematic map of the literature on bioregional planning, based on a case study of the Interim Biogeographic Regionalization for Australia (IBRA), to identify where and how such schemes have been used in scientific research. We identified 67 relevant studies, finding that the majority investigated biodiversity exclusively within a single bioregion (65.7%), with 18 of these studies splitting the targeted bioregion based on administrative boundaries. Most used inferential techniques (74.6%) or pattern-based measures (68.7%), and few studies (9%) both considered biodiversity across multiple bioregions and compared findings between bioregions. Species were investigated ten times more frequently than ecosystems attributes, with mammals and birds monopolizing scientists’ attention. These findings show that our knowledge of biodiversity at bioregional scales is patchy, even for well-studied taxa, and that we have a limited understanding of the synthetic relationship between biodiversity and IBRA bioregions (which are demarcated according to other biophysical factors). This creates a barrier for systematic conservation planning, which requires unbiased information on the spatial attributes of biodiversity, and therefore this knowledge deficit warrants more attention.