Biology subjects

Daru, B. H.

Publications and source records attributed to Daru, B. H..

10 recordsLinked to original sources

bioRxiv2026

Understanding the biogeographic processes behind the accumulation of modern-day marine biodiversity.

Marine biodiversity is nonrandomly distributed, with high species richness in the Central Indo-Pacific and lower richness elsewhere 1. Understanding the biogeographic processes underlying these uneven marine biodiversity patterns can enable the formulation of fundamental theories for how biodiversity accumulates over time and in space 2. Here, we conduct a global cross-taxon ancestral range reconstruction for 14,856 species representing four marine groups: cetaceans, seagrasses, reef-forming corals, and ray-finned fishes, to investigate the processes underlying the accumulation of extant biodiversity across marine biogeographic realms. In-situ speciation was the dominant biogeographic process across all groups, particularly in the tropics for cetaceans, seagrasses, and corals. These groups also showed high numbers of emigration events originating in the tropics, supporting the tropical niche conservatism hypothesis 3,4. Meanwhile ray-finned fishes exhibit the highest per-lineage rates of in-situ speciation and dispersal at high latitudes, reaffirming the expectation of elevated speciation in polar and temperate regions 5. In seagrasses, corals, and fishes, extinction was lowest in the tropics, especially in the Central Indo-Pacific, supporting the center of survival hypothesis in which the Central Indo-Pacific realm had the lowest rate of extinction across evolutionary time 6. Our study shows that the processes that led to the accumulation of extant marine biodiversity are complex, with remarkable variation across taxa, biogeographic realms, and across evolutionary time.

evolutionary biology↗

bioRxiv2025

Vascular plant extinctions outpace colonizations under climate change

Climate change is expected to shift plant distributions poleward and upslope, yet requires global empirical evidence. Using historical range shifts from global herbarium specimens for 109,242 vascular plant species over the past 28 years as baseline, we fit 1.8 million species distribution models on a global dataset of 184,545 vascular plant species to project future range shifts over an equivalent period, the next 20 years (2021-2040). We find that plant species have already shifted their distribution centroids at a median velocity of 5.6 km per year globally, exceeding projected future velocities of 3.27 km yr per year. Projected shifts will vary widely in direction and magnitude, with varied velocities, colonization and extinction rates. Shifts will vary across clades with Superasteridae, Gymnosperms and Monocots moving at slower velocities, and Ferns, Chloranthales, and Magnoliidae with faster velocities. Although most clades will shift polewards, velocities will be highest in temperate and boreal regions, while shifts will be slower in regions of high topographic variation in the tropics. High latitude species will trend poleward and upslope, while desert shrubs, and tropical conifer forests will show slower and directional shifts. Extinctions will outpace colonizations, confirming that climate change will be a driver of biodiversity loss. Colonization will be frequent in protected areas, higher elevations, and among threatened species whereas extinctions will cluster near species historical ranges and at lower elevations. Our findings show the complexity of climate-driven range shifts and emphasize the importance of considering multiple interacting processes beyond simple latitudinal or elevational movements.

ecology↗

bioRxiv2025

A spatially explicit delineation of transition zones for biogeographic regionalization

O_LIA central goal of biogeography is to partition the worlds biota into meaningful biogeographical regions. While naturalists have long delineated biogeographic regions using hierarchical hard clustering approaches, they have often acknowledged the existence of transition zones. However, such transition zones have not been empirically identified or distinguished from hard clusters. Transition zones are outstanding areas for understanding the processes that shape biotic assembly; however, a coherent framework for delineating them is lacking. C_LIO_LIHere, we propose a framework to empirically identify and analyze transition zones through a new metric, the "Transition Zone Index (TZI)". The TZI decomposes the proportional contribution of multiple biotas to a spatial unit (called a map cell) derived from a Grade of Membership model into a single quantitative measure per cell using Shannon entropy principles. The transition zones can then be quantified and presented as a gradient, scaled from TZI = 0 (indicating distinctive bioregions) to TZI = 1 (corresponding to the highly transitional areas with maximally admixed biotas). Finally, we implement spatial regression models to detect the predictors of these transition zones. C_LIO_LIWe demonstrate the application of our framework using vascular plants of southern Africa. Through the spatial variation of TZI, our approach represents transition zones as a continuous gradient of biotic turnover between bioregions. These transition zones were found to be either previously delineated as discrete clusters or incorporated into neighboring clusters. Our approach effectively captures both the intensity and width of transitional dynamics, showing that these patterns are primarily shaped by precipitation. C_LIO_LIBiogeographic transition zones are a measurable gradient, and our framework provides a robust quantitative foundation for detecting and analyzing the drivers of these areas. This improves our ability to understand the patterns and processes underlying biogeographic transition and provides important implications for conservation planning and biodiversity management. C_LI

ecology↗

bioRxiv2025

Late Quaternary climate-driven shifts in arctic plant distributions

AimGlaciation events shaped the present distribution of many plants and their biodiversity in the northern hemisphere. Glacial expansion forced many species south and came with much colder global temperatures, while glacial recession brought warmer temperatures and newly colonizable land without competition. However, the changes in plant diversity associated with glacial retreat and the ensuing climatic changes is not well understood. In this study, we quantify Late Quaternary climate-driven changes in Arctic plant diversity by integrating climatic shifts in species distributions since the last glacial maximum (20-16 kya) and mid-Holocene (5 kya) across the circumpolar arctic. LocationThe geographic arctic, 66{degrees}N. TaxonVascular plants. MethodsWe built species distribution models using phyloregion v. 1.0.9 in R using occurrence data from the Global Biodiversity Information Facility and climate rasters from Worldclim v2.1 for the present and v1.4 for the mid-Holocene and Last Glacial Maximum. Results and DiscussionWe found limited evidence for decreases in weighted endemism, and species richness along with diverging north-south shifts in the centroids of many distributions contrary to expectations of increased alpha diversity since the last glacial maximum. Decreases in species alpha diversity, while already quite low in the arctic, may be reflective of an increasingly variable arctic climate that disfavors plants with a slow dispersal ability. This is especially important given the projected increase in global temperature across many shared socioeconomic pathway scenarios and can be contrasted with our results of the Mid-Holocene, which was roughly a degree warmer than it is today. The arctic is presently warming at roughly two to five times the rate of the mid-latitudes and equator and understanding how plants have responded in the past will help inform on how they may change in the future.

ecology↗

bioRxiv2025

Climate and regional plant richness drive diet specialization in butterfly caterpillars

Studies of coevolution, ecosystem processes, and latitudinal diversity gradients are improved by understanding variation in resource specialization. Insect herbivory is one of the most ubiquitous terrestrial ecological associations that drives the evolution of plants and insects. However, a broad understanding of how and why herbivore diet specificity varies worldwide is lacking. Here, we use global datasets of butterfly and plant distributions to investigate patterns and drivers of butterfly larval diet breadth. Hostplant richness and phylogenetic diversity showed non-monotonic latitudinal patterns that narrowed near the equator and temperate latitudes and broadened at mid-tropical latitudes and the poles. Diet breadth showed a negative relationship with plant family richness, but we also uncovered an interaction between precipitation seasonality and temperature. Our study builds on 60 years of study of butterfly-hostplant evolution to provide valuable insights into how these processes continue to shape plant and herbivore dynamics in response to global environmental changes.

ecology↗

bioRxiv2021

The Post-2020 Global Biodiversity Framework must safeguard the Tree of Life

Following our failure to fully achieve any of the 20 Aichi biodiversity targets, the future of biodiversity rests in the balance. The Convention on Biological Diversitys Post-2020 Global Biodiversity Framework (GBF) presents us with the opportunity to preserve Natures Contributions to People (NCPs) for current and future generations through conserving biodiversity and averting extinction across the Tree of Life. Here we call attention to our need to conserve the Tree of Life to maintain its benefits into the future as a key mechanism for achieving intergenerational equity. We highlight two indicators available for adoption in the post-2020 GBF to monitor our progress towards safeguarding the Tree of Life. The Phylogenetic Diversity indicator, adopted by IPBES, can be used to monitor biodiversitys capacity to maintain NCPs for future generations. The EDGE (Evolutionarily Distinct and Globally Endangered) Index monitors how well we are performing at averting the greatest losses across the Tree of Life by conserving the most distinctive species. By committing to safeguarding the Tree of Life post-2020, we can reduce biodiversity loss to preserve natures contributions to humanity now and into the future.

ecology↗

bioRxiv2020

GreenMaps: a Tool for Addressing the Wallacean Shortfall in the Global Distribution of Plants

The exponential growth of species occurrence data can facilitate dynamic biodiversity analyses. However, raw biodiversity data alone should not be used indiscriminately due to inherent sampling biases, impediments that contribute to Wallacean shortfall (i.e. the paucity of species geographic information). It has been suggested that Wallacean shortfall is a common phenomenon across taxa, however, there is no global assessment geared toward overcoming this impediment for plants, despite the fundamental role of plants in ecosystem stability, food security and biodiversity conservation. Here, I present GreenMaps, a new tool that will permit a rapid initial assessment of the Wallacean shortfall for plants by building base maps of species predicted distributions upon which citizen science participation could contribute to spatial validation of the actual range occupied by species. The initial stages of GreenMaps have now been accomplished, providing a massive dataset of modeled range maps for over 194,000 vascular plant species. This will make it the largest and only global assessment of geographic distributions for plant species at scales relevant to research and conservation. Ultimately, GreenMaps will interface with a mobile application to enable volunteers from any region of the world to validate predicted species distributions to be used for the generation of new and improved global map of plant distributions.

ecology↗

bioRxiv2020

phyloregion: R package for biogeographic regionalization and spatial conservation

O_LIBiogeographical regionalization is the classification of regions in terms of their biotas and is key to understanding biodiversity patterns across the world. Previously, it was only possible to perform analysis of biogeographic regionalization on small datasets, often using tools that are difficult to replicate. C_LIO_LIHere, we present phyloregion, a package for the analysis of biogeographic regionalization and spatial conservation in the R computing environment, tailored for mega phylogenies and macroecological datasets of ever-increasing size and complexity. C_LIO_LICompared to available packages, phyloregion is three to four orders of magnitude faster and memory efficient for cluster analysis, determining optimal number of clusters, evolutionary distinctiveness of regions, as well as analysis of more standard conservation measures of phylogenetic diversity, phylogenetic endemism, and evolutionary distinctiveness and global endangerment. C_LIO_LIA case study of zoogeographic regionalization for 9574 species of squamate reptiles (amphisbaenians, lizards, and snakes) across the globe, reveals their evolutionary affinities, using visualization tools that allow rapid identification of patterns and underlying processes with user-friendly colours-for example- indicating the levels of differentiation of the taxa in different regions. C_LIO_LIUltimately, phyloregion would facilitate rapid biogeographic analyses that accommodates the ongoing mass-production of species occurrence records and phylogenetic datasets at any scale and for any taxonomic group into completely reproducible R workflows. C_LI

bioinformatics↗

bioRxiv2018

Herbarium records reveal early flowering in response to warming in the southern hemisphere

Premise of the StudyHerbarium specimens are increasingly used as records of plant flowering phenology, which has advanced for many species in response to climate change. However, most herbarium-based studies on plant phenology focus on taxa from temperate parts of the northern hemisphere. Here, we explore flowering phenologic responses to climate in a temperate/subtropical plant genus Protea (Proteaceae), an iconic group of woody plants with year-round flowering phenology and endemic to sub-Saharan Africa. Protea is widely used in horticulture and is a flagship genus for the flora of the hyperdiverse Cape Floristic Region.\n\nMethodsWe used a database of 2154 herbarium records of 25 Protea species to explore patterns in flowering spanning the past 100 years. We used a circular sliding window analysis to characterize phenological patterns in these aseasonal species, plus a novel linear mixed effects model formulation to test how both site-to-site and year-to-year variation in temperature and precipitation affect flowering date across species.\n\nResultsBoth warmer sites and warmer years were associated with earlier flowering of 3-5 days/{degrees}C. In general, the timing of peak flowering was influenced more strongly by temperature than precipitation. Although species vary widely in when they flower during the year, their phenological responses to temperature are phylogenetically conserved, with closely related species tending to shift flowering time similarly with increasing temperature.\n\nDiscussionTogether, our results point to climate-responsive phenology for this important plant genus. Our results indicate that the subtropical, aseasonally-flowering genus Protea has temperature-driven flowering phenologic responses that are remarkably similar in magnitude to those of better-studied northern temperate plant species, suggesting a generality across biomes that has not been described elsewhere.

ecology↗

bioRxiv2017

Widespread sampling biases in herbaria revealed from large-scale digitization

O_LINon-random collecting practices may bias conclusions drawn from analyses of herbarium records. Recent efforts to fully digitize and mobilize regional floras offer a timely opportunity to assess commonalities and differences in herbarium sampling biases.\nC_LIO_LIWe determined spatial, temporal, trait, phylogenetic, and collector biases in [~]5 million herbarium records, representing three of the most complete digitized floras of the world: Australia (AU), South Africa (SA), and New England (NE).\nC_LIO_LIWe identified numerous shared and unique biases among these regions. Shared biases included specimens i) collected close to roads and herbaria; ii) collected more frequently during spring; iii) of threatened species collected less frequently; and iv) of close relatives collected in similar numbers. Regional differences included i) over-representation of graminoids in SA and AU and of annuals in AU; and ii) peak collection during the 1910s in NE, 1980s in SA, and 1990s in AU. Finally, in all regions, a disproportionately large percentage of specimens were collected by a few individuals. These mega-collectors, and their associated preferences and idiosyncrasies, may have shaped patterns of collection bias via founder effects.\nC_LIO_LIStudies using herbarium collections should account for sampling biases and future collecting efforts should avoid compounding these biases.\nC_LI

plant biology↗