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"Cycadaceae Conservation."
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CITES and cycads : a user's guide
\"This user's guide covers the highly threatened cycad family and how it is regulated by the Convention on International Trade in Endangered Species (CITES). The text is written for the non-expert and the guide explores the major groups of cycads in trade, their distribution, conservation status, use and levels of trade as well as the likelihood of illegal trade. Exemptions from CITES regulations are also outlined, together with suggestions to aid enforcement. The guide includes a fully illustrated PowerPoint training presentation and a checklist of cycad species, their distribution and synonymy.\"--Page 4 of cover.
Book
Conservation genomics of an Australian cycad Cycas calcicola, and the Absence of Key Genotypes in Botanic Gardens
Understanding the genetic diversity of wild populations is fundamental to conserving species in-situ and ex-situ. To aid conservation plans and to inform ex-situ conservation, we examined the genetic diversity of the cycad Cycas calcicola (Cycadaceae). Samples were collected from wild populations in the Litchfield National Park and Katherine regions in the Northern Territory, Australia. Additional samples were obtained from botanic garden plants that were originally collected in the Katherine region, Daly River and Spirit Hills in the Northern Territory, Australia. Using RADseq we recovered 2271 informative genome-wide SNPs, revealing low to moderate levels of gene diversity (uHe = 0.037 to 0.135), very low levels of gene flow, and significant levels of inbreeding (mean FIS = 0.491). Population structure and multivariate analysis showed that populations fall into two genetic groups (Katherine vs Litchfield + Daly River + Spirit Hills). Genetic differentiation was twice as high between populations of the Katherine and Litchfield regions (FST ~ 0.1) compared to within these two regions (FST ~ 0.05). Increasing population fragmentation together with high levels of inbreeding and very little gene flow are concerning for the future adaptability of this species. The results indicated that the ex-situ collections (1) had significantly lower genetic diversity than the wild populations, and (2) only partly capture the genetic diversity present, particularly because the Litchfield National Park populations are not represented. We recommend that ex-situ collections be expanded to incorporate the genetic diversity found in Litchfield National Park and to increase the number of representatives from Daly River/Spirit Hills, and that in-situ populations from the Katherine and Greater Litchfield regions be conserved as separate management units.
Journal Article
Testing the causes of richness patterns in the paleotropics: time and diversification in cycads (Cycadaceae)
The paleotropics harbor many biodiversity hotspots and show many different species richness patterns. However, it remains unclear which factors are the most important in directly shaping richness patterns among regions in the paleotropics (i.e. diversification rates, colonization times, and dispersal frequency). Here we used Cycadaceae as a model system to test the causes of regional richness patterns in the paleotropics. Specifically, we tested the roles of dispersal frequency, colonization time, diversification rates, and their combined role in explaining richness patterns among regions. We generated a well‐sampled, time‐calibrated phylogeny and then used this to estimate dispersal events, colonization times, and diversification rates. Richness patterns were significantly associated with the timing of the first colonization of each region and were best explained by the combined effects of colonization time and diversification rates. The number of dispersal events into each region and the diversification rates of species in each region were not significantly related to richness. Ancestral‐area reconstructions showed frequent migrations across Wallace's line, with a higher diversification rate east of Wallace's line than west of it. Overall, our study shows that colonization time can be an important factor for explaining regional richness patterns in the paleotropics.
Journal Article
Genetic diversity, genetic structure and demographic history of Cycas simplicipinna(Cycadaceae) assessed by DNA sequences and SSR markers
Background
Cycas simplicipinna
(T. Smitinand) K. Hill. (Cycadaceae) is an endangered species in China. There were seven populations and 118 individuals that we could collect were genotyped in this study. Here, we assessed the genetic diversity, genetic structure and demographic history of this species.
Results
Analyses of data of DNA sequences (two maternally inherited intergenic spacers of chloroplast, cpDNA and one biparentally inherited internal transcribed spacer region ITS4-ITS5, nrDNA) and sixteen microsatellite loci (SSR) were conducted in the species. Of the 118 samples, 86 individuals from the seven populations were used for DNA sequencing and 115 individuals from six populations were used for the microsatellite study. We found high genetic diversity at the species level, low genetic diversity within each of the seven populations and high genetic differentiation among the populations. There was a clear genetic structure within populations of
C. simplicipinna
. A demographic history inferred from DNA sequencing data indicates that
C. simplicipinna
experienced a recent population contraction without retreating to a common refugium during the last glacial period. The results derived from SSR data also showed that
C. simplicipinna
underwent past effective population contraction, likely during the Pleistocene.
Conclusions
Some genetic features of
C. simplicipinna
such as having high genetic differentiation among the populations, a clear genetic structure and a recent population contraction could provide guidelines for protecting this endangered species from extinction. Furthermore, the genetic features with population dynamics of the species in our study would help provide insights and guidelines for protecting other endangered species effectively.
Journal Article
Delimitation of Quantitative Morphological Feature of Female Plants of Cycas L. Species of Kannur District, Kerala
Cycas
L. is an economically important threatened genus at risk of extinction due to natural population degradation. The present study observed unexplored populations in the Kannur district, Kerala, India, including the Kannavam Forest Reserve (KF) during 2021–2023. The normality of the datasets was checked using the Anderson-Darling test in R using the “nortest” package, and the variability in distribution was found using integrated R scripts in QGIS 3.0. and SPSS 25. “corr” and “ggcorrplot” packages of RStudio plotted the Pearson’s correlation matrix from normalised datasets. Hierarchical clustering on principal components utilised Euclidean distance matrix and Ward linkage method from “FactoMineR” and “factoextra” packages in RStudio. Normality tests and histograms showed the variability and skewness in the data. Pearson’s correlation matrix revealed a high positive correlation of petiole length with spines to the total length of the petiole (0.74) and the spine percentage on the petiole (0.71). Moreover, megasporophyll characters exhibited a high positive correlation between apical spine length and the length of the infertile lamina of the megasporophyll (0.84) and fertile region length with the number of ovules (0.70). Hierarchical clustering analysis suggested two clusters in the area by retaining eight principal components concerning eigenvalues, scree plots and cumulative variance. Cluster one was
Cycas circinalis
L., and cluster two was
Cycas nathorstii
J. Schust. based on the recorded morphological features. The study reported the existence of
Cycas nathorstii
for the first time in the Kannur district and the Kannavam Forest Reserve.
Journal Article
Leaf Nutrient Relations of Cycads in a Common Garden
Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.
Journal Article
Biotic Threats to Cycas micronesica Continue to Expand to Complicate Conservation Decisions
Invasions of non-native species can threaten native biodiversity, and island ecosystems are ideal for studying these phenomena. In this article, first, we report on the invasive species that combine to threaten the island cycad Cycas micronesica by reviewing the history of previously reported invasions and providing an update of recent invasions. Then, we prioritize the threat status of each herbivore and the interactions among them. Plant damage was initiated in 2003─2005 by the non-native Aulacaspis yasumatsui Takagi armored scale, Erechthias sp. Meyrick leaf miner, and Luthrodes pandava Horsfield butterfly, which elicited unprecedented irruptions of the native Acalolepta marianarum Aurivillius stem borer and increased herbivory by feral pigs (Sus scrofa L.). The combined impact of these five consumers represents the greatest sustained threat to the cycad tree species. Mitigation of the damage caused by phytophagous non-native species is urgently needed to conserve this unique gymnosperm tree.
Journal Article
Does Phytogeography Change with Shifts in Geopolitics? The Curious Case of Cycads in the United States
The United States is currently home to five native cycad species. We provide a discussion on these five cycad species to illuminate how evolutionary and geopolitical processes influence phytogeography and published checklists of threatened plants. The number of threatened species in need of protection within any given country is a product of speciation that is contingent with evolutionary processes. However, this number may change instantaneously along with shifting of geopolitical boundaries brought about by armed conflict between rival states and multilateral negotiations. There are five contemporary cycad species within the United States, and the various historical bilateral and multilateral agreements that have generated this list are reviewed. Three of these five cycad species are threatened and in need of urgent protection. A discussion on the history of United States cycads as a microcosm of worldwide conservation issues is presented, with a focus on how federal conservation endeavors of individual nations may influence the world’s biodiversity crisis.
Journal Article
The Historical Demography and Genetic Variation of the Endangered Cycas multipinnata (Cycadaceae) in the Red River Region, Examined by Chloroplast DNA Sequences and Microsatellite Markers
Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA) sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU). In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species.
Journal Article
Demography of Cycas micronesica on Guam following introduction of the armoured scale Aulacaspis yasumatsui
Following the 2003 invasion of the armoured scale Aulacaspis yasumatsui to Guam, changes to population traits of the dominant Cycas micronesica were determined. Belt transects with a width of 4 m and an average length of 120 m were established in October 2004 to document plant mortality until January 2011. Stem height, basal diameter and leaf number were also measured for each plant and used to determine density, demography and allometric relationships. Allometric traits and a left-skewed demographic structure of the pre-invasion C. micronesica habitat documented a thriving population with high recruitment potential. Aulacaspis yasumatsui dispersed into the study site 4 mo after the initial census. All seedlings were killed within 9 mo and all juvenile plants were killed within 40 ± 10 mo. Mortality reached 92% by 6 y after chronic scale infestations. Allometry and demography of the 2011 survivors described a collapsing C. micronesica population of stressed and reproductively challenged trees with no recruitment. This classic example of the enemy release hypothesis has resulted in a homogeneous decline in plant density from 2007–2011. The trend predicts extirpation of C. micronesica from west Guam habitats by 2019.
Journal Article