Frontiers of Biogeography

Rapid publication seems like an obvious imperative for scientific debate in the digital era. Most, if not all, science publishers aim to shorten the process between first submission and final publication of articles. However, while minimizing editorial handling and post-acceptance processing certainly reduces the time between research being conducted and being read, a "fast-food” publication model may sacrifice quality in the editorial process. We encourage adoption of "slow publishing" for most research journals, where advancing towards higher quality – rather than towards a faster rate – of scientific debate is promoted as a central goal of the editorial and review process.

Alexander von Humboldt conducted his best-known work on the slopes of the Ecuadorian Andes. He did this by applying his own characteristic brand of multidisciplinary scientific approach. This consisted of thorough data collection while synthesizing and visualizing the data in innovative formats. Also important for his scientific success in South America was his collaborative network that helped him to identify specimens and formulate his transformative scientific thoughts. It is no surprise that Humboldt was captivated by Ecuador, as it is one of the most biodiverse places in the world, and this astounding diversity was formed in an intricate, dynamic geological and climatological setting. As of yet, this biodiversity is far from being fully documented and the processes that generated it are still poorly understood. The IBS meeting in Quito 1 and the Second Latin American Congress of Biogeography will form the perfect platform to both commemorate Humboldt while addressing current and unresolved matters concerning the biodiversity of Ecuador and South America at large.

The Humphead wrasse (also known as the Napoleon fish), Cheilinus undulatus, is a highly prized coral reef fish, listed on CITES Appendix II and endangered on the IUCN Red List. It is widespread across much of the Indo-Pacific region. The fish has a 4-6 week pelagic egg and larval stage, suggesting the potential for high connectivity among populations. However, its range spans important biogeographic boundaries that are associated with barriers to gene flow and deep phylogeographic structure in some marine fishes and invertebrates, raising the possibility of significant population genetic structure. We describe preliminarily the genetic structure of the Humphead wrasse across much of its range and consider the implications for effective conservation. Using mitochondrial DNA sequencing (cytochrome b and control region) coupled with microsatellite analyses, we find primarily a signal of eurymixis — i.e., low, heterogeneous population genetic differentiation across much of the species’ range (F ST analogs: <0.11 cytochrome b, <0.09 control region, <0.02 microsatellites) with the exception of modest differentiation primarily toward the peripheries (e.g., Pohnpei, Seychelles; F ST analogs: 0.03–0.24 cytochrome b, 0.05–0.24 control region, 0.03–0.22 microsatellites) — though isolation by distance is not excluded. The general dearth of structure is consistent with population expansion, following an historical bottleneck and with high contemporary gene flow. The implications are that Humphead wrasse is a metapopulation and that its conservation status depends on successful management of a sufficient but currently unknown number and distribution of populations across a multi-national network.

As a result of the pet trade, Africa’s Nile monitor (Varanus niloticus) is now established in North America (Florida). This generalist carnivore is a potential threat to native wildlife, requiring proactive measures to effectively prevent further spread into novel regions. To determine regions at risk, we create and compare alternative ensemble species distribution models (SDMs) using a model selection approach (with 10 possible modeling algorithms grouped according to assumptions). The ensemble SDMs used presence and environmental data from both native (Africa) and nonnative (Florida) locations. The most predictive consensus SDMs for native and native + nonnative data sets (TSS = 0.87; Sensitivity = 93%; Specificity = 94%) were based on the boosted regression tree (BRT), classification tree analysis (CTA), and random forest (RF) modeling algorithms with all environmental predictor variables used. The global Nile monitor SDMs predict strong habitat suitability in tropical and subtropical regions in the Americas, the Caribbean, Madagascar, Southeast Asia, and Australia. Florida Nile monitor populations are less likely to spread into the Neotropics than if pets now in the Southwest USA are released intentionally or accidentally. Management options to avoid this spread into vulnerable regions are to actively prohibit/regulate Nile monitors as pets, enforce those restrictions, and promote exotic pet amnesty programs. The model selection approach for ensemble SDMs used here may help improve future SDM research

Arthropods are a major component of ecosystems, in terms of both their biomass and the variety of functional roles they play. Yet we lack a clear understanding of how arthropod abundance changes along environmental gradients. We compiled published literature on overall arthropod abundances (number of individuals) along elevational gradients and performed a formal meta-analysis on the role of latitude, climatic variables, and interactions with ants in shaping the pattern. Specifically, we asked if patterns of arthropod abundance along different elevational gradients are associated with gradients of seasonality and precipitation and whether ant abundance affects other arthropods. Arthropod abundance peaks at higher elevations at mid-latitudes than low latitudes; hence, the correlation between arthropod abundance and elevation shifts from negative to positive with an increase in latitude. We suggest these patterns reflect a steep elevational gradient in the length of growing season at mid-latitudes, with the short growing season at high elevations in mid-latitudes leading to synchronous emergence and reproduction of arthropods generating a sharp increase in abundance. Precipitation and ant abundance do not have a consistent effect on arthropod abundance along most elevational gradients. However, on gradients with a very dry base and sharp increase in precipitation with elevation, arthropod abundance peaks at higher elevations. Overall, our results suggest that future changes in the length of growing season will impact the elevation at which summer arthropod abundance peaks and the sharpness of the peak, likely affecting diversity and distribution of other taxa that interact with arthropods.

The integration and synthesis of data from varied sources is becoming increasingly common in biogeography and ecology. Although analyses of large, global datasets from multiple, varied sources only became common recently, such studies trace their origin to the early 19th century. Alexander von Humboldt (1769-1859) was an eminent and much-celebrated scientist, who introduced the concept of collecting high-quality quantitative data across continents. More importantly, he championed inter-disciplinary research, data-driven studies, and global comparative syntheses. With these studies, he helped to lay the foundations for the fields of biogeography and ecology, and his ideas, concepts, and scientific approach remain at the forefront of exciting recent developments in both disciplines. Remembering Humboldt’s 250th birthday, we show how his scientific philosophy and visionary approach to multi-disciplinary data integration and synthesis have recently been revitalized due to increasing computing power and the numerous complex environmental challenges facing our planet.

The Himalaya started with mostly immigrant flora but is today home to about 3500–4000 endemic plants that have evolved within a time span of 40–50 million years. It is, however, still unknown as to what factors have been responsible for the development of such high endemism within such a short evolutionary time. It is also unclear as to how plant diversity patterns are structured across the present-day environmental gradients in the Himalaya and whether these diversity patterns will change in the future. My results point towards a positive coincidence between endemic plant species diversification, changes in geo-physical characteristics, and climate in the Himalaya. The present-day plant species richness patterns are hump-shaped, life-form and endemic specific, and scale-dependent. Furthermore, shrublands would emerge as the most successful plant community in future climates, and there would be a need to redesign the Protected Area network due to ensuing climate change in the Himalaya.

Tropical America (the Neotropics) is the most biodiverse realm on Earth and might harbour more species than tropical Asia and Africa combined. The evolutionary history generating this outstanding diversity remains poorly understood partly because data on the geographic distribution of species is scarce. Collections from museums and herbaria can overcome this gap, but uncertain data quality hampers their use, especially in historical biogeography. Here, I highlight the results from recent studies quantifying diversification and bioregion connectivity in the Neotropics using large-scale species occurrence data, and argue that (i) recently developed software to analyse large-scale data provides a methodological route forward for biogeography, and (ii) biotic connectivity within and among bioregions is a common, but underappreciated, process in the evolution of Neotropical diversity.

During the radiation of a clade, diversification rates can show temporal patterns such as a speedup or slowdown, which might relate to different ecological and evolutionary mechanisms. The temporal dynamics of diversification of whole clades are often visualised as a lineage-through-time (LTT) plot, which traces the number of reconstructed lineages at different time points. However, clades do not radiate evenly across space and may show different temporal dynamics in different regions. As such, a biogeographic approach is required to more completely understand temporal diversification dynamics. Here, I present a tool to extract temporal diversity information across different biogeographic regions from the output of commonly used ancestral range estimation models implemented in the R package BioGeoBEARS. The lineages through space and time (LTST) plot allows for visualisation of diversification dynamics in different regions, formatted in an accessible way which can be used for further quantitative analysis.

Vignette sketch of the altitudinal variations in the vegetation of the Andes, extracted from Berghaus H. (ed.) Physikalischer Atlas oder Samlung von Karten (1849 – 1851, Gotha, Verlag von Justus Perthes). The vignette shows a clear influence of Alexander von Humboldt’s work, which is highlighted in this issue of Frontiers of Biogeography (11.2) by the editorial of Hoorn et al. (e44178) and the perspective from Keppel and Kreft (e43187). Image from Buttimer, A. (2012, Epistemology, History, Teaching, 616, doi:10.4000/cybergeo.25478).