scholarly journals Evaluation of reproductive success and conservation strategies for Senecio coincyi (Asteraceae), a narrow and threatened species

2012 ◽  
Vol 60 (6) ◽  
pp. 517 ◽  
Author(s):  
F. Martínez-García ◽  
S. Guerrero-García ◽  
F. Pérez-García

Senecio coincyi is a threatened endemic plant of central western Spain, with a very narrow extent of occurrence. The reproductive success and germination behaviour of this species were studied. The area of occupancy, habitat types and size of 13 known subpopulations of S. coincyi were evaluated. The number of individuals that form all these subpopulations was counted. In addition, the number of flowers and cypselas per fruit head and the number of fruit heads per individual plant were recorded in a subset of subpopulations. Germination tests were carried out to evaluate the effect of temperature and light regimes on, and possible intraspecific variation in, cypsela germination. Cypselas reached very high germination percentages (90–100%) from 15°C to 30°C. However, the germination decreased (19%) at 10°C. The light conditions assayed (16-h light photoperiod and complete darkness) did not significantly affect cypsela germination. In general, there was no intraspecific variability in germination patterns of S. coincyi cypselas. Livestock is the most important factor that can be a threat for this species. S. coincyi showed high reproductive success and, therefore, its conservation problems are not due to agents related to its reproduction, but rather to other factors such as alteration of its habitat caused by the presence of livestock.

2012 ◽  
Vol 64 (3) ◽  
pp. 1001-1016 ◽  
Author(s):  
Felipe Martínez-García ◽  
Silvia Guerrero-García ◽  
Félix Pérez-García

Senecio coincyi (Asteraceae) is a threatened endemic plant of central western Spain. The reproductive biology of this species in relation to the characteristics of its habitats and the possible strategies for its conservation, were studied. The area of occupancy, habitat types and size of 13 known subpopulations of S. coincyi was evaluated. Germination tests were carried out to assess the effect of temperature and light regimes, and the possible intraspecific variation on the cypsela germination. Cypselas reached very high germination percentages (90-100%) from 15?C to 30?C. However, the germination decreased (by about 19%) at 10?C. The light conditions assayed did not significantly affect cypsela germination. In conclusion, S. coincyi showed high sexual reproduction ability, and therefore its conservation problems are not due to agents related to its reproductive biology, but to others, such as the alteration of its habitat caused by the presence of livestock.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 567
Author(s):  
Misty Stevenson ◽  
Kalynn L. Hudman ◽  
Alyx Scott ◽  
Kelsey Contreras ◽  
Jeffrey G. Kopachena

Based on surveys of winter roost sites, the eastern migratory population of the monarch butterfly (Danaus plexippus) in North America appears to have declined in the last 20 years and this has prompted the implementation of numerous conservation strategies. However, there is little information on the survivorship of first-generation monarchs in the core area of occupancy in Texas, Oklahoma, and Louisiana where overwinter population recovery begins. The purpose of this study was to determine the survivorship of first-generation eggs to third instars at a site in north Texas and to evaluate host plant arthropods for their effect on survivorship. Survivorship to third instar averaged 13.4% and varied from 11.7% to 15.6% over three years. The host plants harbored 77 arthropod taxa, including 27 predatory taxa. Despite their abundance, neither predator abundance nor predator richness predicted monarch survival. However, host plants upon which monarchs survived often harbored higher numbers of non-predatory arthropod taxa and more individuals of non-predatory taxa. These results suggest that ecological processes may have buffered the effects of predators and improved monarch survival in our study. The creation of diverse functional arthropod communities should be considered for effective monarch conservation, particularly in southern latitudes.


Zygote ◽  
2020 ◽  
pp. 1-7
Author(s):  
Mariana Machado Evangelista ◽  
Elizabeth Romagosa ◽  
Diógenes Henrique Siqueira-Silva ◽  
George Shigueki Yasui ◽  
Takafumi Fujimoto ◽  
...  

Summary Rivulidae comprises a family of fish largely distributed in Brazil that includes 201 species, of which 125 are considered endangered. This fact emphasizes the need for development of conservation strategies including studies on genetics and reproduction. In this paper, we describe aspects of biology and reproduction of the rivuliid species Hypsolebias sertanejo. We outline the reproductive behaviour of this species under laboratory conditions, analyze ploidy status by flow cytometry, describe reproductive behaviour and performance and test dry and wet incubation of eggs. Although H. sertanejo showed well known patterns of reproductive behaviour, we verified many peculiarities inherent to its reproductive biology. As expected, most individuals were diploid (87.71%), however 14.29% were considered mosaics. Although no sterility was observed within mosaics, infertility of these fish was not fully evaluated. Hatching rate of the eggs collected was very low following both dry and wet incubation (5.04 and 3.79%, respectively). These results provide interesting information regarding the reproductive success of this species, and suggest that chromosomal abnormalities described may reduce the survival of H. sertanejo under natural conditions, limiting the perpetuation of this species, and emphasizing the need for more preservation efforts, including artificial propagation and gene banking.


2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900
Author(s):  
Anass Elouaddari ◽  
Abdelaziz El Amrani ◽  
Jamal JamalEddine ◽  
José G. Barroso ◽  
Luis G. Pedro ◽  
...  

Air-dried aerial parts of wild Cladanthus mixtus were collected from two different regions of Morocco, Bouznika and Oujda, during 2011 and 2012. Forty individual plant samples were hydrodistilled using a Clevenger apparatus and the obtained essential oils were analyzed by GC and GC/MS. The yield obtained varies greatly with a range of 0.3 to 0.8%. The chemical composition of C. mixtus oils changes from one region to another. A total of 53 constituents were identified. To the best of our knowledge, two chemotypes were defined for the first time for this species in the regions studied. 2-Methyl-2- trans-butenyl methacrylate (32.8–35.2%) / ar-curcumene (13–14%) characterize the chemotypeof the C. mixtus plants from Bouznika, and trans-β-farnesene (35.5–50.3%) the chemotype from Oujda.


1992 ◽  
Vol 70 (1) ◽  
pp. 200-204 ◽  
Author(s):  
Andrea L. Corbett ◽  
Pam G. Krannitz ◽  
Lonnie W. Aarssen

The flowers of the arctic poppy (Papaver radicatum L.) track the sun, and the petals of the flowers reflect light towards the ovary. This study investigated the importance of petals to reproductive success in this species. We measured light intensity, ovary temperature, seed weight, and number of seeds produced by flowers that had their petals removed versus flowers with their petals intact. Flowers without petals do not track the sun. Irradiance was greater when the photocell was held coincident with the angle of sun-tracking flowers than when facing upward. Flowers with petals had significantly higher overy temperatures both at the ovary surface and in the ovary interior than did flowers lacking petals. In pairs of flowers on the same individual plant, those with their petals removed had significantly fewer and smaller seeds than control flowers with petals intact. There were site differences in the significance of the treatment effect, but not in the magnitude of the differences between flowers with and without petals. Therefore, the presence of petals resulted in increased irradiance and temperature at and in the ovary, which affected reproductive success. Key words: heliotropism, Papaver radicatum, petals, reproductive success, temperature.


2020 ◽  
Vol 8 ◽  
Author(s):  
Sara Bárrios ◽  
José Sustache ◽  
David Goyder ◽  
Martin Hamilton

Thought to be endemic to the Commonwealth of Puerto Rico, Ruehssia woodburyana (Apocynaceae) was recently discovered at a single location on Norman Island in the British Virgin Islands. Despite an increase in the extent of occurrence and area of occupancy, this species meta-population is very limited with a total of 37 individuals known in the wild. The largest subpopulation, on Mona Island, has only 26 individuals. The species suitable habitat is experiencing a continuing decline due to urban development, grazing by feral ungulates and human-induced forest fires. Conservation action is urgently needed and should be directed towards establishing genetically representative ex situ collections, such as seed for long term storage and live material for propagation. This species is evaluated as Critically Endangered (CR), based on Criteria C2a(i)+D, according to the IUCN Red List Categories and Criteria (version 3.1) and guidelines (Subcommittee IUCN Standards and Petitions 2016). Extensive and regular surveys to the region enable the discovery of new plant records for different countries and islands. In this paper, we record a new island record for Ruehssia woodburyana on Norman Island, in the British Virgin Islands and discuss the species conservation status. Marsdenia woodburyana is transferred to the genus Ruehssia to reflect the resurrection of that genus for species of Marsdenia native to the New World.


2020 ◽  
Vol 44 (2) ◽  
pp. 129-136
Author(s):  
Ramazan Murtazaliev ◽  
Dzhalaludin Anatov ◽  
Jana Ekhvaia ◽  
Ziyarat Guseinova ◽  
Ketevan Batsatsashvili

Plant traits have been used to predict species and community responses to environmental gradients. We studied variation of leaf area (LA), specific leaf area (SLA), flowering shoot number and seed mass along an elevation gradient in the case of Trigonocaryum involucratum, a scree-growing plant endemic to the Caucasus ecoregion. The study had two major aims: (1) to compare the role of intra-population and inter-population variation of functional trait values; and (2) to ascertain dependence between elevation and trait values and their variation. We collected trait data in several populations in Dagestan (Russian Federation), where the species has about a 1000-m amplitude of elevational distribution. The intraspecific variability of trait values was assessed via standard statistical tools (one-way ANOVA and linear regression analysis). The trait values mostly have high inter-population variation (more than 90% for each of the trait values compared to intra-population variation of each trait), indicating adaptation of populations to site conditions. Much higher intra- vs. inter-population variation in SLA at subnival elevations indicates local micro-site diversity and may serve as a buffer against future stress related to climate change. All the trait values negatively but significantly correlate (weakly or moderately) with elevation. Negative correlation presumably shows a certain increase in the limiting effect of the elevation gradient associated with changes in temperature, soil nutrient availability and soil water content, as well as with high solar radiation. More evidence from a broader study of the species throughout its distribution range is needed for firmer conclusions about the intraspecific variability of T. involucratum.


2005 ◽  
Vol 15 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Markus Brändel ◽  
Kai Jensen

This study investigated the effects of various temperature regimes on dormancy and germination inEupatorium cannabinum, a common wetland species in Central Europe. Germination of dry-stored achenes was tested at increasing amplitudes of temperature fluctuations, and stratified achenes were germinated at constant temperatures. Dormancy release was examined in the laboratory at constant temperatures of 3, 8, 12, 15 and 18°C. The effect of an increase in temperature during stratification from 5°C to 15, 18 or 20/10°C on dormancy was tested. Moreover, achenes were exposed to yearly seasonal temperature cycles in the soil in an experimental garden. Germination of dry-stored achenes was not promoted by fluctuating temperatures, while stratified achenes germinated (>5%) over a range of constant temperatures between 9 and 36°C. Dormancy was relieved at all stratification temperatures, but temperatures ≤12°C were more effective than higher temperatures, since germination occurred over a wider range of test conditions after these pretreatments. An induction of secondary dormancy occurred only if the temperature was increased during stratification. Annual dormancy cycles were apparent when achenes were germinated at 15°C, while at 25 and 15/5°C germination was always >60%. The germination behaviour ofEupatoriumis that of a typical wetland species. Thus, non-dormant achenes germinated at relatively high temperatures, and germination was promoted by fluctuating temperatures. The annual course of dormancy revealed that achenes can germinate throughout the growing season under favourable conditions. Achenes sown in an experimental garden germinated in spring, when daily mean temperatures were around 14°C. A decline in viability of achenes after 19 months' burial indicated thatEupatoriumdoes not form a long-term persistent seed bank.


2007 ◽  
Vol 85 (7) ◽  
pp. 629-636 ◽  
Author(s):  
Reinaldo Moreira da Silva ◽  
G. Wilson Fernandes ◽  
Maria Bernadete Lovato

The Serra do Espinhaço in Brazil is under continuous and increasing levels of human disturbance. It has a large number of endemic plant species such as Chamaecrista semaphora (Irwin and Barneby), an endangered species with extremely narrow range. We studied the genetic diversity of C. semaphora and compared it with Chamaecrista mucronata (Spreng.) Irwin and Barneby, a widespread congeneric species distributed over the entire Serra do Espinhaço, in an attempt to provide information for conservation strategies. Two populations of C. mucronata and the only two known populations of C. semaphora from Serra do Cipó were screened for variability using random amplified polymorphic DNA (RAPD) markers. Populations of C. semaphora exhibited a lower percentage of polymorphic markers (16.9%) and Shannon’s Diversity Index (H′pop = 0.124) than C. mucronata populations (43.3% and H′pop = 0.299). Most of the genetic variability of both species studied was distributed within populations; C. semaphora populations (ΦST = 0.198) were less divergent than C. mucronata populations (ΦST = 0.378). The risk of extinction for C. semaphora is large owing to its low level of genetic diversity compared with its widespread congener and because of increasing habitat destruction. Both populations of C. semaphora urgently need protection to maximize the genetic diversity of this species and diminish further substantial loss within the populations.


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