Joaquín Hortal

Understanding how fire and vertical stratification interact to shape insect communities is essential in increasingly fire‐prone montane systems. We investigated how herbivorous insect communities vary across vertical strata (canopy and understory) and fire incidence in 14 altitudinal forest islands within the Espinhaço Range, Brazil. Using data collected in 4 years spanning a 7‐year period (2014–2020), we analyzed the temporal variation of species richness and abundance, and changes in species composition, gains and losses. Despite greater environmental exposure, canopy communities showed lower temporal variation in richness and abundance than those of the understory, suggesting a buffering effect likely driven by consistent resource availability and host‐plant specialization. Fire was not associated with changes in species composition nor species gains, but reduced species losses, particularly in the understory, possibly by favoring generalist species with broad ecological tolerance. Species gains were higher in the canopy, indicating that it may act as a recipient layer for dispersers from the surrounding campo rupestre matrix. Our findings highlight complex, stratum‐specific fire effects and suggest that post‐disturbance recovery may promote greater differentiation and stability of herbivorous insect communities across forest strata in montane ecosystems.

The limitations, biases and uncertainties associated with occurrence records often limit their utility to describe species’ realised bioclimatic niches. We assess changes in the perception of the realised niche of 156,500 terrestrial vascular plant species when excluding records that fall out of their recognized distribution (either native or introduced) as documented by their biogeographical status in Plants of the World Online. Filtering records following the species' geographical distribution recognised by experts results in a distortion of the representation of their niches, in some cases reducing the bioclimatic space occupied by more than half. This reduction affected between 20-40% of the species across orders, and raised up to 68% for Osmundales and Pinales or 83% in Equisetales. While most of the species evaluated (96%) only presented records in native botanical countries, about 90% of the species with introduced records expanded their realised niche beyond native climatic conditions. This calls for caution when selecting occurrence records from public repositories to conduct massive analyses on terrestrial plants. Validating these niche discrepancies derived from the curation process will allow drawing robust conclusions about species’ responses to environmental changes.

Equivalent numbers represent biodiversity as the effective number of equally distinct units, typically species, and can be partitioned across scales. In practice, they summarize each unit of biodiversity by a single value and compare units pairwise, misrepresenting units that are better described as distributions and the relationships between several units that share the same space. We introduce an equivalent-number index for assemblages of units represented as probability density functions (PDFs) over a continuous space, estimated as the integral of the pointwise maximum across abundance-weighted PDFs. Resulting equivalent PDF numbers fulfil elementary properties of classical equivalent numbers, and support additive partitioning across any number of nested scales. We illustrate the framework with case studies across three domains: (1) measuring trait diversity considering intraspecific variability in grasslands, (2) partitioning realized bioclimatic niches among clades of Carnivora, and (3) understanding seasonal changes in the partitioning of fish home ranges in geographic space.

Standardising taxonomic names is an essential step in biodiversity studies to ensure robust data aggregation under the most recent accepted species nomenclature. Fuzzy (inexact) matching is widely used in this process to detect correspondences between scientific names that differ due to alternative spelling or orthographic mistakes. Such an approach assumes that species names are sufficiently distinct such that names differing in just a few characters in fact refer to the same taxon, but this has rarely been evaluated. Across c. 230,000 marine species names, we show that name similarity is common: 19.34% of specific epithets differ by three or fewer edits from another epithet within the same genus. Shared epithets are also widespread within and across phyla, occurring in 73% of all marine species; in 6.05% of these cases, the associated genera differ by three or fewer edits. This level of similarity increases the risk of incorrect matches, limiting the reliability of automated text-string tools in biodiversity big data analyses and highlighting the importance of combining post-matching filters with systematic and authorship information in taxonomic workflows to support name resolution beyond orthographic similarity.

Occurrence records are fundamental for ecological and evolutionary research, providing key information on species' geographic ranges. However, these records are often taxonomically, spatially, and temporally biased, requiring caution in their use. Here, we analysed the spatial coverage of occurrence records for over 3500 snake species worldwide to identify geographical gaps, biases, and priority areas for surveys. We calculated completeness metrics to detect well‐sampled cells and assessed whether these cells adequately represent the climatic conditions across biogeographic realms. We also identified priority areas for surveys based on geographic and environmental distances from well‐sampled cells, which may reflect different environmental conditions and species. Our results show that the number of well‐sampled cells is higher in the Nearctic, Western Palearctic, and Australasia, whereas the Afrotropical, Eastern Palearctic, and Indomalayan realms remain poorly sampled. Although the Neotropical realm has a relatively high number of well‐sampled cells, they are spatially clustered, leaving large areas under‐sampled. Overall, well‐sampled cells fail to represent the majority of climatic types present in each realm; also, rare climates are underrepresented in the Nearctic, Neotropical, and Indomalayan realms. We highlight priority areas in all realms, particularly in high‐latitude regions of the Nearctic and Palearctic and in low‐latitude regions of the Neotropical, Afrotropical, Indomalayan, and Australasia realms. While the low number of occurrence records in extremely high latitudes may reflect low abundance and species richness, these areas can still harbour undescribed species and high taxonomic uncertainty. However, given the limited funding and resources, we suggest that redirecting survey efforts to neglected and species‐rich regions is essential for enhancing strategic planning for snake biodiversity conservation.

Standardising taxonomic names is an essential step in biodiversity studies to ensure robust data aggregation and up-to-date, valid species nomenclature. Fuzzy (inexact) matching is widely used in this process to detect correspondences between scientific names that differ due to typographical errors. Such an approach assumes that species names are sufficiently distinct such that names differing in just a few characters in fact refer to the same taxon, but this has rarely been evaluated. Across c. 230,000 marine species names, we show that name similarity is common: 28.37% of specific epithets differ by three or fewer edits from another epithet within the same genus. Shared epithets are also widespread within and across phyla, occurring in 73% of all marine species; in 7.35% of these cases, the associated genera differ by three or fewer edits. This level of similarity increases the risk of incorrect matches, limiting the reliability of automated text-string tools in biodiversity big data analyses and highlighting the importance of considering systematic and authorship information into taxonomic workflows to support name resolution beyond orthographic similarity.

Although taxonomy is an evolving discipline, taxonomic change is rarely accounted for in macroecological studies. By tracking the history of species descriptions and synonymizations of Amazonian palms, we reveal shifts in species counts across space and time, the factors associated with taxonomic lumping, and the time needed to detect synonyms. The 175 Amazonian palm species known to date are the result of a gradual accumulation of new descriptions and a few distinct revision events that led to the recognition of approximately 800 heterotypic synonyms. Most of these were detected after the mid-1990s and caused an 80% decrease in species counts within just three decades. The time to detect synonyms ranged from 3 to 227 years. Species with a large population, widespread distribution and those described in early years were more frequently lumped. This suggests undetected synonyms inflate species richness unevenly across taxa and regions. These findings highlight the importance of taxonomic revisions for our understanding of biodiversity. Systematic efforts across lineages are needed to advance plant taxonomy, thereby strengthening ecological analyses and conservation assessments.

The limitations, biases and uncertainties associated with digitally available information often limit the utility of occurrence records to properly describe the species’ realised bioclimatic niche. Here we assess changes in the perception of the realised niche of terrestrial vascular plant species after applying filters based on the geographical location of records according to their biogeographical status (native or introduced range), and range outliers documented by Plants of the World Online. We used Principal Component Analyses to describe the realised bioclimatic niches of 156,500 species. Our results show that restricting the available occurrence records to the delimited geographical distributions results in a distortion of the representation of these niches. The bioclimatic niche can be reduced by more than half of the environmental volume occupied when we filter out species records based on expert map distributions. Between 20-40% of the species in each order presented decreases in their observed realised niche after discarding records outside of their recognised range of distribution. Strikingly, this percentage raised up to 68% in Osmundales and Pinales or 83% in Equisetales. Most of the species evaluated (96%) only presented data in native ranges, but c. 90% of the species with introduced ranges expanded their realised niche in the invaded areas, evidencing that biological invasions often occur outside of the native climatic conditions. This calls for caution when selecting occurrence records from public repositories to conduct massive analyses using all available information on terrestrial plants. Validating discrepancies in niche estimations derived from the curation process will allow drawing robust conclusions about species’ responses to environmental changes.

Several studies show that species richness patterns are determined by current climate and Pleistocene climatic oscillations. Additionally, habitat availability is an important driver of current species diversity, especially in aquatic ecosystems where lentic (standing water) and lotic (running water) habitats play distinct roles in species composition and richness. Odonates, an order of aquatic insects, exhibit distinct adaptive traits in response to climate and to lentic and lotic habitats. In this work, we study the species richness patterns of European odonates and the influence of past and current climate, and habitat availability. The study covers 124 species distributed across Europe (excluding Russia and all European islands except Great Britain and Ireland), divided into three groups: all odonates, lentic species, and lotic species. Notably, lentic species total 70% of the studied Odonata species, thus influencing overall species richness patterns. We analyzed their diversity in Northern and Southern Europe, divided according to the 0 °C Isotherm of the Last Glacial Maximum (21,000 years ago), using data on current and Last Glacial Maximum climate (temperature and precipitation), as well as on habitat data from land cover and hydrology GIS maps. Our results suggest that the species richness patterns of dragonflies and damselflies are largely determined by the water-energy balance, with temperature influencing the decline in richness towards the north and precipitation determining the decline towards the south. Past climate oscillations affect species richness in southern and northern Europe. Habitat availability also influences odonate diversity to a lesser extent, with a positive correlation between lotic species richness and their habitat availability. In contrast, lentic species richness showed a negative correlation with the availability of lentic habitats. We evaluate whether the variation of dragonfly species richness across Europe is determined by current climate, the climatic conditions during the last ice age, and the availability of freshwater habitats. Dragonfly species richness is higher in Central Europe and decreases both northwards and southwards from there. These variations are primarily determined by current and past climate, and to a lesser extent by habitat availability. Temperature determines the northward decrease in species richness, while the southward decrease is so by precipitation. The last ice age climate had a greater influence than current climate in northern Europe, while in southern Europe current climate has a greater influence, particularly for species related to standing water habitats. Species richness is higher in areas with more rivers and water courses, while the relationship with the availability of standing water habitats is more nuanced.