Environmental change can create opportunities for increased rates of lineage diversification, but continued species accumulation has been hypothesized to lead to slowdowns via competitive exclusion ...and niche partitioning. Such density-dependent models imply tight linkages between diversification and trait evolution, but there are plausible alternative models. Little is known about the association between diversification and key ecological and phenotypic traits at broad phylogenetic and spatial scales. Do trait evolutionary rates coincide with rates of diversification, are there lags among these rates, or is diversification niche-neutral? To address these questions, we combine a deeply sampled phylogeny for a major flowering plant clade—Saxifragales—with phenotype and niche data to examine temporal patterns of evolutionary rates. The considerable phenotypic and habitat diversity of Saxifragales is greatest in temperate biomes. Global expansion of these habitats since the mid-Miocene provided ecological opportunities that, with density-dependent adaptive radiation, should result in simultaneous rate increases for diversification, niche, and phenotype, followed by decreases with habitat saturation. Instead, we find that these rates have significantly different timings, with increases in diversification occurring at the mid-Miocene Climatic Optimum (∼15 Mya), followed by increases in niche and phenotypic evolutionary rates by ∼5 Mya; all rates increase exponentially to the present. We attribute this surprising lack of temporal coincidence to initial niche-neutral diversification followed by ecological and phenotypic divergence coincident with more extreme cold and dry habitats that proliferated into the Pleistocene. A lack of density-dependence contrasts with investigations of other cosmopolitan lineages, suggesting alternative patterns may be common in the diversification of temperate lineages.
Plant bulbs are modified shoot systems comprised of short internodes with apical bud(s) surrounded by layers of leaf bases. Bulb diameters can vary greatly, with overall bulb size playing a role in ...flower formation and resource allocation. Despite the importance of bulb size to the overall fitness of an individual, evolutionary and ecological aspects of this trait have been almost completely neglected. Examining over 2,500 herbarium vouchers for 115 selected species, we analyzed monocot tunicate bulb size within a phylogenetic context in order to investigate its evolutionary significance. We recorded two bulb diameter optima and observed that as bulb size increases taxa inhabit warmer areas with less temperature seasonality. Furthermore, we found that hysteranthous taxa, a habit where leaves emerge separately from flowers, exhibit overall larger bulbs potentially due to reliance upon belowground stored resources to flower rather than on current environmental inputs. This work highlights the importance of including the belowground portion of plants into ecological and evolutionary studies in order to gain a more complete understanding of the evolution of plant forms and functions.
Utilizing herbarium specimen data, we test hypotheses related to tunicate bulb size variation across the monocots. We found that as bulb size increases, taxa tend to inhabit warmer, less thermally variable habitats. We also found that hysteranthous taxa (i.e., those that flower without leaves present) have larger bulbs relative to synanthous taxa (i.e., flower and leaves appear simultaneously).
New information technologies have enabled the scientific collections community and its stakeholders to adapt, adopt, and leverage novel approaches for a nearly 300 years old scientific discipline. ...Now, few can credibly question the transformational impact of technology on efforts to digitize scientific collections, as IT now reaches into almost every nook and cranny of society. Five to ten years ago this was not the case. Digitization is an activity that museums and academic institutions increasingly recognize, though many still do not embrace, as a means to boost the impact of collections to research and society through improved access. The acquisition and use of scientific collections is a global endeavor, and digitization enhances their value by improved access to core biodiversity information, increases use, relevance and potential downstream value, for example, in the management of natural resources, policy development, food security, and planetary and human health. This paper examines new opportunities to design and implement infrastructure that will support not just mass digitization efforts, but also a broad range of research on biological diversity and physical sciences in order to make scientific collections increasingly relevant to societal needs and interest.
Angiosperm phylogeny: 17 genes, 640 taxa Soltis, Douglas E.; Smith, Stephen A.; Cellinese, Nico ...
American journal of botany,
April 2011, Letnik:
98, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Premise of the study. Recent analyses employing up to five genes have provided numerous insights into angiosperm phylogeny, but many relationships have remained unresolved or poorly supported. In the ...hope of improving our understanding of angiosperm phylogeny, we expanded sampling of taxa and genes beyond previous analyses. Methods: We conducted two primary analyses based on 640 species representing 330 families. The first included 25260 aligned base pairs (bp) from 17 genes (representing all three plant genomes, i. e., nucleus, plastid, and mitochondrion). The second included 19846 aligned bp from 13 genes (representing only the nucleus and plastid). Key results: Many important questions of deep-level relationships in the nonmonocot angiosperms have now been resolved with strong support. Amborellaceae, Nymphaeales, and Austrobaileyales are successive sisters to the remaining angiosperms (Mesangiospermae), which are resolved into Chloranthales + Magnoliidae as sister to Monocotyledoneae + Ceratophyllaceae + Eudicotyledoneae. Eudicotyledoneae contains a basal grade subtending Gunneridae. Within Gunneridae, Gunnerales are sister to the remainder (Pentapetalae), which comprises (1) Superrosidae, consisting of Rosidae (including Vitaceae) and Saxifragales; and (2) Superasteridae, comprising Berberidopsidales, Santalales, CaryophyHales, Asteridae, and, based on this study, Dilleniaceae (although other recent analyses disagree with this placement). Within the major subclades of Pentapetalae, most deep-level relationships are resolved with strong support. Conclusions: Our analyses confirm that with large amounts of sequence data, most deep-level relationships within the angiosperms can be resolved. We anticipate that this well-resolved angiosperm tree will be of broad utility for many areas of biology, including physiology, ecology, paleobiology, and genomics.
To be computationally reproducible and efficient, integration of disparate data depends on shared entities whose matching meaning (semantics) can be computationally assessed. For biodiversity data ...one of the most prevalent shared entities for linking data records is the associated taxon concept. Unlike Linnaean taxon names, the traditional way in which taxon concepts are provided, phylogenetic definitions are native to phylogenetic trees and offer well-defined semantics that can be transformed into formal, computationally evaluable logic expressions. These attributes make them highly suitable for phylogeny-driven comparative biology by allowing computationally verifiable and reproducible integration of taxon-linked data against Tree of Life-scale phylogenies. To achieve this, the first step is transforming phylogenetic definitions from the natural language text in which they are published to a structured interoperable data format that maintains strong ties to semantics and lends itself well to sharing, reuse, and long-term archival. To this end, we developed the Phyloreference Exchange Format (Phyx), a JSON-LD-based text format encompassing rich metadata for all elements of a phylogenetic definition, and we created a supporting software library, phyx.js, to streamline computational management of such files. Together they form a foundation layer for digitizing and computing with phylogenetic definitions of clades.
The accelerating growth of data and knowledge in evolutionary biology is indisputable. Despite this rapid progress, information remains scattered, poorly documented and in formats that impede ...discovery and integration. A grand challenge is the creation of a linked system of all evolutionary data, information and knowledge organized around Darwin's ever-growing Tree of Life. Such a system, accommodating topological disagreement where necessary, would consolidate taxon names, phenotypic and geographical distributional data across clades, and serve as an integrated community resource. The field of evolutionary informatics, reviewed here for the first time, has matured into a robust discipline that is developing the conceptual, infrastructure and community frameworks for meeting this grand challenge.
Recent climate projections have shown that the distribution of organisms in island biotas is highly affected by climate change. Here, we present the result of the analysis of niche dynamics of a ...plant group, Memecylon, in Sri Lanka, an island, using species occurrences and climate data. We aim to determine which climate variables explain current distribution, model how climate change impacts the availability of suitable habitat for Memecylon, and determine conservation priority areas for Sri Lankan Memecylon. We used georeferenced occurrence data of Sri Lankan Memecylon to develop ecological niche models and assess both current and future potential distributions under six climate change scenarios in 2041–2060 and 2061–2080. We also overlaid land cover and protected area maps and performed a gap analysis to understand the impacts of land‐cover changes on Memecylon distributions and propose new areas for conservation. Differences among suitable habitats of Memecylon were found to be related to patterns of endemism. Under varying future climate scenarios, endemic groups were predicted to experience habitat shifts, gains, or losses. The narrow endemic Memecylon restricted to the montane zone were predicted to be the most impacted by climate change. Projections also indicated that changes in species’ habitats can be expected as early as 2041–2060. Gap analysis showed that while narrow endemic categories are considerably protected as demonstrated by their overlap with protected areas, more conservation efforts in Sri Lankan forests containing wide endemic and nonendemic Memecylon are needed. This research helped clarify general patterns of responses of Sri Lankan Memecylon to global climate change. Data from this study are useful for designing measures aimed at filling the gaps in forest conservation on this island.
With the aim of understanding how climate change affects the distribution of island‐dwelling plants, this research used occurrence data of a Sri Lankan woody plant group, Memecylon, to develop ecological niche models and assess future potential distributions under six climate change scenarios. Our results provided insights into patterns of responses of Sri Lankan Memecylon to global climate change. Additionally, data from this study are useful for designing measures aimed at filling the gaps in forest conservation on this island.
Speciose clades usually harbor species with a broad spectrum of adaptive strategies and complex distribution patterns, and thus constitute ideal systems to disentangle biotic and abiotic causes ...underlying species diversification. The delimitation of such study systems to test evolutionary hypotheses is difficult because they often rely on artificial genus concepts as starting points. One of the most prominent examples is the bellflower genus Campanula with some 420 species, but up to 600 species when including all lineages to which Campanula is paraphyletic. We generated a large alignment of petD group II intron sequences to include more than 70% of described species as a reference. By comparison with partial data sets we could then assess the impact of selective taxon sampling strategies on phylogenetic reconstruction and subsequent evolutionary conclusions.
Phylogenetic analyses based on maximum parsimony (PAUP, PRAP), Bayesian inference (MrBayes), and maximum likelihood (RAxML) were first carried out on the large reference data set (D680). Parameters including tree topology, branch support, and age estimates, were then compared to those obtained from smaller data sets resulting from "classification-guided" (D088) and "phylogeny-guided sampling" (D101). Analyses of D088 failed to fully recover the phylogenetic diversity in Campanula, whereas D101 inferred significantly different branch support and age estimates.
A short genomic region with high phylogenetic utility allowed us to easily generate a comprehensive phylogenetic framework for the speciose Campanula clade. Our approach recovered 17 well-supported and circumscribed sub-lineages. Knowing these will be instrumental for developing more specific evolutionary hypotheses and guide future research, we highlight the predictive value of a mass taxon-sampling strategy as a first essential step towards illuminating the detailed evolutionary history of diverse clades.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Land use changes by humans have eliminated more than half of the wetlands in Florida over the last 200 years, and additional losses are anticipated as a consequence of climate change and ongoing ...development activities that will accommodate a rapidly growing human population. Both spell danger for the biodiversity and ecosystem services in Florida, and data are needed to inform conservation priorities and actions concerning threatened or endangered wetland species. We modeled the projected distribution of an endangered epiphyte native to the forested wetlands in South Florida, Guzmania monostachia (Bromeliaceae), in response to changing climate and sea level conditions. We constructed ecological niche models (ENMs) under the present framework by using georeferenced occurrence points and projected them into the past and future under different scenarios. Our future climate-based ENMs predicted small losses in suitable habitat for G. monostachia in South Florida, with expansions into higher latitudes due to the warmer climate. In contrast, the models predicted a considerable, although non-detrimental, loss of suitable habitat due to rising sea levels. The combined results suggest that human activity is and will remain the largest threat to G. monostachia in Florida, and conservation efforts should focus on preserving existing habitats that will remain above sea level and explore possibilities for assisted migration.
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