Revisiting the classification of Melastomataceae: Habit and fruit evolution
Bertolonieae (Melastomataceae) have traditionally comprised more than 100 Neotropical species in a dozen genera. However, recent phylogenetic analyses have shown that Bertolonieae are not monophyletic, which implies that suites of morpholocial and ecological features have evolved independently in unrelated groups of Melastomataceae.
The authors conducted molecular phylogenetic analyses in order to evaluate tribal and generic limits, reconstruct morphological patterns, and identify clades in the tribe Bertolonieae. Bertolonieae as traditionally recognized were recovered in four major lineages across the tree, and Bertolonieae are recircumscribed here to include only the genus Bertolonia. Geographical and morphological congruence in the results suggests that the convergence of morphological characters historically used to identify Bertolonieae s.l. may be explained by different lineages around the world that occupy similar habitats (i.e., mostly shaded and moist herbaceous layers under the rainforest canopy). Dependence on water for seed dispersal and limited dispersability may also explain the restriction of the taxa to such similar habitats.
Botanical Journal of the Linnean Society, May, 2019
Habitat quality and disturbance drive lichen species richness in a temperate biodiversity hotspot
Relatively little is known about how lichens–obligate symbiotic organisms–respond to disturbance. Successful establishment and development of lichens require a minimum of two compatible yet usually unrelated species to be present in an environment, suggesting disturbance might be particularly detrimental.
To address this gap, the authors focused on lichens, which are obligate symbiotic organisms that function as hubs of trophic interactions. The investigation was conducted in the southern Appalachian Mountains, USA. The authors conducted complete biodiversity inventories of lichens (all growth forms, reproductive modes, substrates) across 47, 1-ha plots to test classic models of responses to disturbance (e.g., linear, unimodal).
The analyses recovered a strong, positive, linear relationship between lichen biodiversity and habitat quality: lower levels of disturbance correlate to higher species diversity. With few exceptions, additional variables failed to significantly explain variation in diversity among plots for the 509 total lichen species. Strong, detrimental impacts of disturbance on lichen biodiversity raises concerns about conservation and land management practices that fail to incorporate complete estimates of biodiversity, especially from ecologically important organisms such as lichens.
Oecologia, May 15, 2019
Genetic mechanisms underlying perianth epidermal elaboration of Aristolochia ringens (Aristolochiaceae)
The authors studied the morpho-anatomical and molecular basis of perianth elaboration of Aristolochia ringens. The study provides the first large scale analysis of perianth genes in Aristolochia and presents an overall view of the transcriptomic profiles in three well-differentiated portions of the perianth.
Candidate genes were identified that are likely involved in epidermal tissue development, metabolic functioning, and cell proliferation, and that were linked to observed morpho-anatomical patterning throughout the three perianth portions. The three CINCINNATA copies found are differentially expressed in the three perianth portions likely controlling rates of cell proliferation. Although particular biological roles of a number of candidate genes here identified in the Aristolochia perianth have not been characterized, the results provide an important platform to further investigate the molecular networks of epidermal-specific developmental processes and differential cell proliferation.
Flora, April, 2019
Biodiversity recovery of Neotropical secondary forests
This large team of authors assessed how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition.
Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes.
Science Advances, March 6, 2019
First record of Usnea (Parmeliaceae) growing in New York City in nearly 200 years
During a series of lichen surveys in New York City, the authors found a single thallus of Usnea on one very large, old red oak (Quercus rubra) at Woodlawn Cemetery in the Bronx. The individual was too poorly developed to identify by its morphology and chemistry, so they used a DNA barcoding approach.
Molecular data confidently assigned the thallus as Usnea mutabilis. Finding this thallus was highly notable, as it is the first report of an Usnea from New York City since 1824.
Journal of the Torrey Botanical Society, February 25, 2019
Pleistocene range expansions might explain striking disjunctions between eastern Brazil, Andes and Mesoamerica in Leandra
Most species of Leandra are narrow endemics, but a few present striking disjunct distributions between eastern Brazil and Andes or Mesoamerica. The authors used Climatic Niche Modeling to better understand the distributions of the species in this clade.
The results suggest that disjunct distributions in Leandra may have been shaped by cyclical range expansions during colder Pleistocene periods, followed by local extinctions during warmer interglacial periods. The results also support a short‐dispersion/stepping‐stone migration scenario to account for the observed disjunctions in this clade.
Journal of Systematics and Evolution, January 24, 2019
From plant ontology to gene ontology and back
In this article, NYBG scientists Dennis Stevenson and Cecilia Zumajo explore terminology related to structures of the seed, addressing the question of which of the two integuments in the angiosperms is the equivalent of the single integument in the gymnosperms.
In angiosperms, the gene INNER NO OUTER (INO) is involved in the proper development of the outer integument but not in the inner integument and in ino mutants there is no outer integument. INO genes are angiosperm specific as no orthologs have been found in gymnosperms. Thus, it appears that the inner integument of the angiosperms is equivalent –homologous- to the single integument of the gymnosperms and the PO terms can be revised accordingly.
Current Plant Biology, October 4, 2018
Patterns of biodiverse, understudied groups do not mirror those of the surrogate groups that set conservation priorities
The authors–two NYBG curators and the first-author graduate student–conducted biodiversity inventories of lichens, woody plants, and sedges at 32 sites on the Mid-Atlantic Coastal Plain of eastern North America between November 2012 and June 2015.
They then compared alpha diversity and community assemblages of each organismal group across the sites, and compared selected minimal reserve sets in order to visualize biodiversity patterns and assess whether specific components of vascular plants (sedges and woody plants) serve as an effective surrogate for lichens. The results show a lack of congruence between species richness patterns across organismal groups and suggest that the mechanisms that shape patterns of diversity are not identical. An important conclusion is that identifying and incorporating specific biodiversity indicators for understudied groups in conservation policy is necessary if the protection of such groups is to be ensured.
Biodiversity and Conservation, August 22, 2017
Traditional lifestyles, transition and implications for healthy aging
A team of researchers including New York Botanical Garden scientist Michael Balick has found that citizens of a Pacific island nation who are in transition between traditional, agrarian communities and modernized areas are more likely to have unhealthful lifestyles than those living in either traditional or modernized communities.
The findings from the study of residents of the state of Pohnpei in the Federated States of Micronesia have important implications that are applicable to the greater global population, including the United States, given that contemporary western society is transitional at its core.
The PLOS ONE article was published by an interdisciplinary research group that includes authors from The New York Botanical Garden, Southern Arizona VA Health Care System, North Carolina State University, American Academy of Family Physicians, Columbia University, Conservation Society of Pohnpei, Federated States of Micronesia (FSM), The Nature Conservancy—Micronesia Office, and University of Hawaii at Manoa.
PLOS ONE, March 12, 2019
The first complete plastid genomes of Melastomataceae are highly structurally conserved
NYBG scientists Fabian Michelangeli and Marcelo Reginato report the first full plastid sequences of Melastomataceae, compare general features of the sampled plastomes to other sequenced Myrtales, and survey the plastomes for highly informative regions for phylogenetics.
Melastomataceae plastomes are no exception for the general patterns observed in the genomic structure of land plant chloroplasts, being highly conserved and structurally similar to most other Myrtales. Despite the fact that the full plastome phylogeny shares most of the clades with the previously widely used and reduced data set, some changes are still observed and bootstrap support is higher. The plastome data set presented here is a step towards phylogenomic analyses in the Melastomataceae and will be a useful resource for future studies.
Peer J, November 29, 2016
Science Magazine: This lily’s cousin is an ear of corn
As different as they seem, corn, daylilies, towering palm trees, and diminutive lady’s slipper orchids have a lot in common. Now, a new genetic study published by 20 authors including NYBG’s Dr. Dennis Stevenson reveals why: Even though all of these plants are landlubbers today, their ancestor lived in water.
Science, November 5, 2018