Nishanta Rajakaruna

Nishanta Rajakaruna
California Polytechnic State University, San Luis Obispo | Cal Poly · Department of Biological Sciences

PhD (University of British Columbia, 2003)

About

131
Publications
54,781
Reads
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3,318
Citations
Additional affiliations
August 2022 - present
North-West University
Position
  • Scholar (Fulbright)
September 2016 - June 2017
National Institute of Fundamental Studies - Sri Lanka
Position
  • US Fulbright Scholar
June 2014 - April 2022
North-West University
Position
  • Extraordinary Professor
Description
  • Visiting Professor in geobotany and serpentine ecology

Publications

Publications (131)
Article
Full-text available
Plants adapted to special soil types are ideal for investigating evolutionary processes, including maintenance of intraspecific variation, adaptation, reproductive isolation, ecotypic differentiation, and the tempo and mode of speciation. Common garden and reciprocal transplant approaches show that both local adaptation and phenotypic plasticity co...
Article
Some of the largest expanses of ultramafic soils occur in South Asia, but knowledge of the plant diversity and biogeochemistry of these systems in Sri Lanka is very limited. This study aimed to assess the plant diversity and bedrock and foliar chemistry of all known Sri Lankan ultramafic outcrops. The field survey yielded a total of 132 plant taxa...
Article
Ultramafic ecosystems are renowned for high endemism and habitat specialization. However, most of our understanding of ultramafic plant ecology comes from Mediterranean and temperate climes, raising questions about the generalizability of plant responses to ultramafic soils. This is especially apparent in tropical ultramafic ecosystems which exhibi...
Chapter
It is widely known that anthropogenic inputs, particularly from modern agriculture and fossil fuel combustion, are severely altering the nitrogen (N) cycle. Humans have doubled the amount of reactive N (NR) input into our environments, causing it to accumulate in ecosystems. However, N is anything but stationary. In various forms, NR enters the atm...
Article
Lichens are among the most prominent and successful life forms of metal-rich habitats, including ultramafic rocks and soils. Research on lichens of ultramafic habitats is limited, however, especially on the North American continent. This review examines geographic and ecological patterns of ultramafic lichen assemblages by synthesizing published re...
Article
Potentially toxic metal (PTM) enrichment of the soil-plant system in ultramafic and mining regions is a global concern as it affects the food chain. With expanding mining industry, it is important to assess if anthropogenic factors (i.e., land use practices) have a greater influence in this regard compared to natural factors (i.e., topography). Loc...
Preprint
Full-text available
Aims Plants growing on quarry tailings at the Irankouh Pb/Zn mine encounter both drought stress and high levels of Pb. To better understand role of drought and Pb in plant adaptation to Pb/Zn quarry tailings, we compared effects of drought stress (simulated by polyethylene glycol - PEG) and Pb, individually and in concert, to determine how these st...
Article
Suddenly lichens are hot after hiding in plain sight for nearly two centuries – a recent expedition rapidly revealed at least three new local lichen species, honouring two of South Africa’s botanical stalwarts in the process
Article
Nickel release from anthropogenic and natural sources into the environment has resulted in biomagnification of terrestrial ecosystems. Here, we studied the biotransfer and toxicokinetics of nickel (Ni) along the soil < faba bean < aphid-ladybird food chain. The soil was spiked with the following Ni concentrations (in mg kg⁻¹ soil ww); T0 (0), T1 (2...
Article
A preventative treatment of fire retardants at high-risk locales can potentially stop a majority of wildfires. For example, over 80% of wildfire ignitions in California occur at high-risk locales such as adjacent to roadsides and utility infrastructure. Recently a new class of ammonium polyphosphate retardants was developed with enhanced adherence...
Article
The new genus Burrowsia (Caliciaceae) is proposed to accommodate the new species B. cataractae, which is known from only a single locality in Mpumalanga, South Africa. Burrowsia is characterized by its pigmented, submuriform ascospores and ascus with an apical tube structure, and also by its DNA sequence data that place it outside related buellioid...
Chapter
Plants found on serpentine soils provide model systems to investigate adaptations to extreme environments. Serpentine soils are poorly developed, prone to drought conditions, often poor in essential nutrients such as phosphorous and calcium, and rich in heavy metals such as nickel and chromium. Although exposure to high concentrations of heavy meta...
Article
Full-text available
Purpose This study was conducted to evaluate the synergistic effects of organic amendments and soil water status on trace metal release from serpentine soil. Materials and methods Two organic amendments, dendro-biochar (BC) and municipal solid waste compost (CM), were added to serpentine soil at four different ratios, specifically 2.5:0.0, 2.5:1.0...
Article
Full-text available
Heavy metal contamination in soils can influence plants and animals, often leading to toxicosis. Heavy metals can impact various biochemical processes in plants, including enzyme and antioxidant production, protein mobilization and photosynthesis. Hydrolyzing enzymes play a major role in seed germination. Enzymes such as acid phosphatases, protease...
Article
Full-text available
Lead (Pb) contamination of agroecosystems is a serious issue as Pb is a persistent pollutant that is retained in soil for long, causing toxicities to organisms. This study examines biotransfer of Pb from soils treated with different concentrations of Pb through a broad bean (Vicia faba L.)–aphid (Aphis fabae Scop.)–ladybird (Coccinella transversali...
Article
Full-text available
Diversity of secondary lichen metabolites and their relationship to substrate and environmental parameters were studied in saxicolous lichens in the Middle and South Urals of Russia. Atranorin, usnic acid, gyrophoric acid, zeorin, norstictic acid, antraquinones and stictic acid were found in 73, 42, 41, 37, 36, 35 and 32 species, respectively, of 5...
Article
Full-text available
Unfortunately, in the original publication of the article, Prof. Yong Sik Ok's affiliation was incorrectly published. The author's affiliation is as follows.
Article
Full-text available
The boom of tanneries in north India has converted the river Ganga into a waste dumping stream. The tanneries discharge their heavy metal-rich effluents into the river. Tissues of two-year-old tree saplings of Dalbergia sissoo, soil sediments and river water samples were collected from three sites along the river Ganga at Jajmau, Kanpur. Site-1 was...
Article
The affiliations of the coauthors, Antony van der Ent and Shota Sakaguchi have been incorrectly published in the original publication of the article. The correct affiliations are provided in this correction.
Article
Full-text available
The 9th International Conference on Serpentine Ecology (ICSE) was held in Tirana and Pogradec (Albania) from June 5 to 9, 2017. More than 100 delegates from 29 countries around the world gathered to present their research on recent advances in: (i) ultramafic soils, (ii) biogeochemistry, (iii) diversity of ultramafic flora, microflora and fauna, (i...
Article
Full-text available
Climate and geography can influence biological soil crust (BSC) community composition, but local heterogeneity in variables such as soil characteristics or microclimate gradients can also impact cryptogamic diversity. Heavy metals and nutrient imbalances in serpentine soils are known to influence the distributions of higher plants, but cryptogamic...
Article
The paper summarizes literature on climate, soil chemistry, vegetation and metal accumulation by plants found on ultramafic substrata in the circumboreal zone (sensu Takhtajan, Floristic regions of the world, 1986) of the Northern Hemisphere. We present a list of 50 endemic species and 18 ecotypes obligate to ultramafic soils from the circumboreal...
Article
The importance of calcium in nickel tolerance was studied in the nickel hyperaccumulator plant Alyssum inflatum by gene transformation of CAX1, a vacuolar membrane transporter that reduces cytosolic calcium. CAX1 from Arabidopsis thaliana with a CaMV35S promoter accompanying a kanamycin resistance gene was transferred into A. inflatum using Agrobac...
Article
While higher plant communities found on ultramafics are known to display peculiar characteristics, the distinguishability of any peculiarity in lichen communities is still a matter of contention. Other biotic or abiotic factors, rather than substrate chemistry, may contribute to differences in species composition reported for lichens on adjacent ul...
Article
Full-text available
Globally, ultramafic outcrops are renowned for hosting floras with high levels of endemism, including plants with specialised adaptations such as nickel or manganese hyperaccumulation. Soils derived from ultramafic regoliths are generally nutrient-deficient, have major cation imbalances, and have concomitant high concentrations of potentially phyto...
Article
Full-text available
Five nickel hyperaccumulators belonging to the Asteraceae are known from ultramafic outcrops in South Africa. Phytoremediation applications of the known hyperaccumulators in the Asteraceae, such as the indigenous Berkheya coddii Roessler, are well reported and necessitate further exploration to find additional species with such traits. This study t...
Conference Paper
Full-text available
Elevated concentrations of metal release from soils into groundwater generate ecological, agricultural and human health related complications. This study investigates the influence of different physical (i.e., water content) and chemical (e.g., presence of protons and ligands) changes on the release of heavy metals in heavy metal rich serpentine so...
Article
Seaweeds (macroalgae) accumulate heavy metals from seawater and can therefore serve as biological monitors of marine pollution. In this paper, we present data on the tissue chemistry of seaweeds from the area of Callahan Mine, an intertidal copper and zinc mine in Brooksville, ME, USA, abandoned in the 1970s and now designated as a Superfund site....
Conference Paper
Full-text available
Soil water content can affect the amount of metal released into the environment by serpentine soil. Two sets of serpentine soil with different water content, i.e., saturated point (SP) and field capacity (FC), were incubated for two days and the leachate was eluted. The soil sample and the leachate were tested for exchangeable Ni, Mn, Co and Cr. So...
Poster
Full-text available
Most of the ultramafic sites had higher chlorophyll-a content and had a more diverse algal component and less diverse fungal and bacterial component, than the mafic sites in the same geographical area. Although results did not show a clear difference between the composition of the bacterial, fungal and algal populations of ultramafic and non-ultram...
Conference Paper
Full-text available
We compared the cryptogamic composition of ultramafic and non-ultramafic soils to determine how soil characteristics can influence biological soil crust (BSC) community composition. Samples from ultramafic and non-ultramafic soils were enriched with liquid growth media to determine the algal and cyanoprokaryote genera present. Total genomic DNA was...
Article
Full-text available
Globally, ultramafic outcrops are renowned for hosting floras with high levels of endemism, including plants with specialised adaptations such as nickel or manganese hyperaccumulation.Soils derived from ultramafic regoliths are generally nutrient-deficient, have major cation imbalances, and have concomitant high concentrations of potentially phytot...
Article
Full-text available
We conducted 12 days of field surveys on five mountains over 1100 m in elevation (Katahdin, North Brother, South Brother, Mount Coe, and The Owl) in Baxter State Park (BSP), Maine during the summers of 2013-14. In addition, we examined historic manuscripts, unpublished data, and herbarium records for plant records from the five mountains. Katahdin,...
Article
Full-text available
The increase in usage of heavy metals in different industrial activities causes their existence in effluents. Excessive concentrations of these heavy metals pollute soil and water. Heavy metals cause toxicities and other harmful effects not only in humans and animals but also in plants and soil microorganisms. Heavy metals disrupt many biochemical...
Article
Full-text available
Limestone is a distinctive substrate that has significant effects on soils and plants. The present study characterizes the diversity of vascular plants, bryophytes, and lichens at the Simonton Corner Quarry Preserve, an abandoned limestone quarry in Rockport, Maine, USA, which was in operation in the late 1800s. We document vascular plant diversity...
Article
Full-text available
Purpose In this study, we investigated the effect of biochar (BC) and fungal bacterial co-inoculation (FB) on soil enzymatic activity and immobilization of heavy metals in serpentine soil in Sri Lanka. Materials and methods A pot experiment was conducted with tomatoes (Lycopersicon esculentum L.) at 1, 2.5, and 5 % (w/w) BC ratios. Polyphenol oxida...
Article
Full-text available
Since 1991, researchers from approximately 45 nations have participated in eight International Conferences on Serpentine Ecology (ICSE). The ICSE conferences are coordinated by the International Serpentine Ecology Society (ISES), a formal research society whose members study geological, pedological, biological and applied aspects of ultramafic ecos...
Data
Welcome to the latest contents alert for Australian Journal of Botany. This double special issue of the journal forms Part 1 of the Proceedings of the 8th International Conference on Serpentine Ecology (ICSE). Coordinated by the International Serpentine Ecology Society, these conferences offered an international forum to discuss and synthesise mult...
Article
Full-text available
Since 1991, researchers from approximately 45 nations have participated in eight International Conferences on Serpentine Ecology (ICSE). The ICSE conferences are coordinated by the International Serpentine Ecology Society (ISES), a formal research society whose members study geological, pedological, biological and applied aspects of ultramafic ecos...
Article
Full-text available
The objective of this work was to analyze the vegetation dynamics of a xeric serpentine savanna located in the Mid-Atlantic, USA. We employed vegetation surveys of thirty-two, 10 x 15 m quadrats to obtain woody species composition, density, basal area, and developed a spatial physiochemical dataset of substrate geochemistry to independently summari...
Article
Full-text available
Compared to serpentine floras of southeast Asia, Sri Lanka’s serpentine vegetation is impoverished with regards to serpentine endemics and nickel hyperaccumulators. All species so far documented from Sri Lanka’s serpentine outcrops also have non-serpentine populations; it is unclear if the serpentine populations are physiologically distinct and...
Article
Full-text available
Plants endemic to serpentine soils are adapted to harsh environmental conditions typical of those soils, particularly relatively low (<1) Ca:Mg ratios. We compared survival of two perennial Alyssum species native to Iran under experimental manipulations of Ca:Mg ratio, including when Ca:Mg ratio was varied under conditions of high ammonium concentr...
Article
Full-text available
Gabbro is a mafic plutonic rock that is common in the Sierra Nevada, Klamath Mountains, and Peninsular Ranges of the California Floristic Province. Its mineralogical and chemical compositions span the range between those of peridotite, an ultramafic rock, and diorite, a rock more silicic than gabbro. A broad range of nutrient element compositions m...
Article
Full-text available
Despite a large body of work on the serpentine-substrate effect on vascular plants, little work has been undertaken to describe algal communities found on serpentine soils derived from peridotite and other ultramafic rocks. We report a preliminary study describing the occurrence of algae and cyanoprokaryotes on mafic and ultramafic substrates from...
Article
Full-text available
This study was conducted to understand the role of bacterial-fungal interactions on heavy metal uptake by Zea mays plants. A pot experiment was conducted for 90 days with Z. mays in serpentine soil inoculated with a Gram-negative bacterium, fungus (Aspergilllus sp.) and both microbes to determine the effects of inoculation on nickel, manganese, chr...
Article
Full-text available
Heavy metals are released into the environment by both anthropogenic and natural sources. Highly reactive and often toxic at low concentrations, they may enter soils and groundwater, bioaccumulate in food webs, and adversely affect biota. Heavy metals also may remain in the environment for years, posing long-term risks to life well after point sour...
Article
Full-text available
Spatial heterogeneity of soil conditions combined with intraspecific variation confer site-specific edaphic tolerance, resulting in local adaptation and speciation. To understand the geoecological processes controlling community assembly of woodland tree species on serpentine and mafic soils, we investigated resource gradients and provenance (geogr...
Article
Full-text available
This study was conducted to understand the role of bacterial-fungal interactions on heavy metal uptake by Zea mays plants. A pot experiment was conducted for 90 days with Z. mays in serpentine soil inoculated with a Gram-negative bacterium, fungus (Aspergilllus sp.) and both microbes to determine the effects of inoculation on nickel, manganese, chr...
Chapter
Full-text available
Heavy metals pose a significant threat to arable land around the world. We describe the dangers of heavy metal contamination in agricultural settings and discuss methods of assessing the risk of metal contamination in agricultural soils and crop plants. We propose remediation options such as phytoextraction and the use of soil amendments as well as...
Article
Full-text available
Background: The flora of serpentine/ultramafic soils provides an excellent model system for the study of natural selection in plant populations. Streptanthus polygaloides is a nickel hyperaccumulator that is endemic to serpentine soils in the Sierra Nevada of California, and has four floral morphs (yellow, purple, yellow-to-purple and undulate). Ai...
Article
Full-text available
Purpose: Serpentine soils derived from ultramafic rocks release elevated concentrations of toxic heavy metals into the environment. Hence, crop plants cultivated in or adjacent to serpentine soil may experience reduced growth due to phytotoxicity as well as accumulate toxic heavy metals in edible tissues. We investigated the potential of biochar (B...
Article
Full-text available
Metal-contaminated soils provide numerous stressors to plant life, resulting in unique plant communities worldwide. The current study focuses on the vascular plants of Callahan Mine in Brooksville, ME, USA, a Superfund site contaminated with Cu, Zn, Pb, and other pollutants. One hundred and fifty-five taxa belonging to 50 families were identified,...
Article
Full-text available
Geochemistry and mineralogy of rocks play important roles in the occurrence of individual lichen species and assembly of lichen communities. Whereas lichens of metal-enriched settings have been a focus of study for many decades, only a few such lichen inventories exist for North America. We reexamined the lichen biota of Pine Hill, a serpentine out...
Conference Paper
Serpentine soils release heavy metals into the environment. We investigated the potential of woody biochar (BC), a waste byproduct of dendro-power industries in Sri Lanka, as a soil amendment to immobilize and reduce the phytotoxicity of bioavailable Ni, Cr and Mn in serpentine soil. Metal release experiments were carried out to investigate the rel...
Article
Full-text available
Alyssum inflatum is a native of serpentine soils and is able to hyperaccumulate nickel (Ni), but the importance of Ni to reproduction in the species is unknown. We investigated if reproductive fitness is enhanced by Ni in the growth medium, and included a treatment involving a relatively high level of Mg to provide a comparison with elevated levels...
Article
Full-text available
Whereas lichen-habitat relations have been well-documented globally, literature on lichens of vernal pools is scant. We surveyed six vernal pools at Acadia National Park on Mount Desert Island, Maine, USA for their lichen diversity. Sixty-seven species were identified, including seven species that are new reports for Acadia National Park: Fuscidea...