Widespread sampling biases in herbaria revealed from large-scale digitization

Daru, Barnabas H.; Park, Daniel; Primack, Richard B.; Willis, Charles G.; Barrington, David S.; Whitfeld, Timothy J. S.; Seidler, Tristram G.; Sweeney, Patrick W.; Foster, David R.; Ellison, Aaron M.; Davis, Charles C.

doi:10.1101/165480

Cited by 56 publications

(96 citation statements)

References 80 publications

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“…The results of global analyses of other taxonomic groups (e.g., insects or fungi) might differ from the results in the present study, but data on those taxonomic groups are not comparable to the data we used here. Museum collections, the source of our data on angiosperms and vertebrates, are extensive but rarely reflect systematic sampling (Daru et al, ; Meyer, Weigelt, & Kreft, ). As more data become readily available through ongoing digitization efforts and as new methods of phylogenetic analysis are developed, some gaps and biases might be reduced.…”

Section: Discussionmentioning

confidence: 99%

Spatial overlaps between the global protected areas network and terrestrial hotspots of evolutionary diversity

Daru

Roux

Gopalraj

et al. 2019

Global Ecol Biogeogr

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Aim A common approach for prioritizing conservation is to identify concentrations (hotspots) of biodiversity. Such hotspots have traditionally been designated on the basis of species‐level metrics (e.g., species richness, endemism and extinction vulnerability). These approaches do not consider phylogenetics explicitly, although phylogenetic relationships reflect the ecological, evolutionary and biogeographical processes by which biodiversity is generated, distributed and maintained. The aim of this study was to identify hotspots of phylogenetic diversity and compare these with hotspots based on species‐level metrics and with the existing protected areas network. Location Global. Time period Contemporary. Major taxa studied Terrestrial vertebrates (mammals, birds and amphibians) and angiosperms. Methods We used comprehensive phylogenies and distribution maps of terrestrial birds, mammals, amphibians and angiosperms to identify areas with high concentrations of phylogenetic diversity, phylogenetic endemism, and evolutionary distinctiveness and global endangerment. We compared the locations of these areas with those included within the current network of protected areas and concentrations of species‐level indices: species richness, species endemism and species threat. Results We found spatial incongruence among the three evolutionary diversity metrics in each taxonomic group. Spatial patterns of diversity and endemism also differed among taxonomic groups, with some differences between vertebrates and angiosperms. Complementarity analyses of phylogenetic diversity identified the minimal area that encapsulates the full branch lengths for each taxonomic group. The current network of protected areas and species‐level hotspots largely does not overlap with areas of high phylodiversity. Main conclusion Overall, < 10% of hotspot areas were designated as protected areas. Patterns of diversity, endemism and vulnerability differ among taxonomic groups.

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Section: Discussionmentioning

confidence: 99%

Spatial overlaps between the global protected areas network and terrestrial hotspots of evolutionary diversity

Daru

Roux

Gopalraj

et al. 2019

Global Ecol Biogeogr

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“…However, data from herbaria present challenges that require careful consideration (e.g., see Meyer, Weigelt, & Kreft, ; Daru et al, ; Meineke et al, ). The spatial resolution of older specimens is coarse and, in our data, limited to the county level within the US.…”

Section: Discussionmentioning

confidence: 99%

Herbarium specimens reveal increasing herbivory over the past century

et al. 2018

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Predicting how ecological interactions will respond to global change is a major challenge. Plants and their associated insect herbivores compose much of macroscopic diversity, yet how their interactions have been altered by recent environmental change remains underexplored. To address this gap, we quantified herbivory on herbarium specimens of four plant species with records extending back 112 years. Our study focused on the northeastern US, where temperatures have increased rapidly over the last few decades. This region also represents a range of urban development, a form of global change that has shown variable effects on herbivores in the past studies. Herbarium specimens collected in the early 2000s were 23% more likely to be damaged by herbivores than those collected in the early 1900s. Herbivory was greater following warmer winters and at low latitudes, suggesting that climate warming may drive increasing insect damage over time. In contrast, human population densities were negatively associated with herbivore damage. To explore whether changes in insect occurrence or abundance might explain shifts in herbivory, we used insect observational records to build climate occupancy models for lepidopteran herbivores (butterflies and moths) of our focal plant species. These models show that higher winter temperatures were associated with higher probability of insect herbivore presence, while urbanization was associated with reduced probability of herbivore presence, supporting a link between insect herbivore occurrence and herbivory mediated through environment. Synthesis. Using a temporal record of plant herbivory that spans over a century, we show that both temperature and urbanization influence insect damage to plants, but in very different ways. Our results indicate that damage to plants by insect herbivores will likely continue to increase through time in the northeastern US as global temperatures rise, but that urbanization may disrupt local effects of winter warming on herbivory by excluding certain herbivores. These changes may scale to shape ecosystem processes that are driven by herbivory, including plant productivity.

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“…For example, Thomson, Moles, Auld, and Kingsford () found a “height effect” on seed dispersal distance, with taller species dispersing further than smaller species. Finally, since they are more easily collected, shrub or terrestrial herb species are expected to be better sampled than epiphytes, lianas or trees, potentially resulting in differing sampling bias among growth forms (Daru et al., ).…”

Section: Introductionmentioning

confidence: 99%

Beyond trees: Biogeographical regionalization of tropical Africa

Droissart

Dauby

Hardy

et al. 2018

Journal of Biogeography

109

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Aim To delineate bioregions in tropical Africa and determine whether different plant growth forms (trees, terrestrial herbs, lianas and shrubs) display the same pattern of regionalization, diversity and endemism as the whole flora. Location Tropical Africa (excl. Madagascar), from 20° N to 25° S. Taxon Vascular plants. Methods Analyses were based on occurrences of 24,719 vascular plant species distributed across tropical Africa extracted from the RAINBIO database. The majority of species (93%) were classified into four growth forms: terrestrial herbs, trees, shrubs and lianas. Biogeographical regions (bioregions) were delimited using a bipartite network clustering approach on the whole dataset and then separately for each growth form. Relationships among bioregions were investigated using non‐metric multidimensional scaling ordination, flora nestedness and endemism patterns. Results Analyses of the whole dataset identified 16 bioregions and 11 transition zones. These were congruent with most of the currently recognized phytogeographical classifications, and also highlighted previously under‐recognized bioregions. Bioregion endemism rates were lower and species richness higher when compared to estimates from the White/Association pour l'Etude Taxonomique de la Flore d'Afrique Tropicale (AETFAT) classification. Analysed separately, plant growth forms showed contrasting geographical patterns. Bioregionalization was better resolved for closed forest types using trees and lianas and for open vegetation types using terrestrial herbs, while shrubs showed good discriminative power in all vegetation types. Main conclusions We show that distribution patterns based on solely trees are not sufficient to define floristic bioregions in tropical Africa. Analyses of spatial patterns using different growth forms are complementary, likely reflecting different evolutionary processes and ecological relationships. The contribution of growth forms to delimit geographical floristic patterns across tropical Africa is of critical importance for land use planning and management, and for selecting priority conservation areas.

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Widespread sampling biases in herbaria revealed from large-scale digitization

Cited by 56 publications

References 80 publications

Spatial overlaps between the global protected areas network and terrestrial hotspots of evolutionary diversity

Spatial overlaps between the global protected areas network and terrestrial hotspots of evolutionary diversity

Herbarium specimens reveal increasing herbivory over the past century

Beyond trees: Biogeographical regionalization of tropical Africa

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