Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate

2014 ◽  
Vol 36 (3) ◽  
pp. 249 ◽  
Author(s):  
P. Norman ◽  
R. Denham ◽  
M. J. Calvert
Keyword(s):  
Life Histories ◽  
Arid Zone ◽  
Survival Rates ◽  
Climatic Conditions ◽  
Severe Drought ◽  
High Survival ◽  
Ecosystem Structure ◽  
Background Rate ◽  
Average Maximum ◽  
Eastern Australia

Shrubs are an important component of vegetation throughout the world. They are particularly significant in semiarid environments where they can dominate, driving ecosystem structure and functioning, and shaping land use. Life-history information was derived for Eremophila sturtii R.Br. and Dodonaea viscosa subsp. angustissima J.G.West, two widespread and common shrubs of semiarid eastern Australia. Plants growing under background climatic conditions took between 2 and 4 years to become established, attained the capacity to reproduce sexually at between 10 and 12 years, were in a sexually reproductive stage for between 17 and 28 years and lived an average maximum of 33–40 years. Under background climatic conditions between 70 and 80% of plants that entered the juvenile stage survived to sexual maturity while under severe drought this proportion fell to between 40 and 60%. Juvenile plants, particularly of E. sturtii, experienced the highest mortality under background conditions while, when exposed to severe drought, older plants, particularly D. viscosa subsp. angustissima in the intermediate stage, experienced the greatest increase in mortality, dying at more than twice the background rate. The high survival rates of E. sturtii and D. viscosa subsp. angustissima shown here, even under extreme drought conditions and in grazed- and ungrazed areas, help to explain why these shrub species have been observed to dominate vegetation in large areas of eastern Australia.

Flowering of Blandfordia grandiflora (Christmas bells) in response to fire frequency and temperature

2020 ◽  
Vol 68 (6) ◽  
pp. 449
Author(s):  
Stephen J. Griffith ◽  
Susan Rutherford
Keyword(s):  
Survival Rates ◽  
Fire Frequency ◽  
Perennial Herb ◽  
Fire Season ◽  
Frequency Effect ◽  
High Survival ◽  
Flowering Response ◽  
Flowering Season ◽  
Eastern Australia ◽  
Blandfordia Grandiflora

Blandfordia grandiflora (Blandfordiaceae) is a resprouting perennial herb in wet heathland of coastal and tableland habitats on mainland eastern Australia. It has attractive turbinate flowers of considerable horticultural value. Blandfordia grandiflora is reported to have an enhanced flowering response in the first post-fire flowering season, and management prescriptions advocate frequent fire as beneficial for the species. Nonetheless, the present study appears to be the first to document the flowering response and fate of individual plants exposed to a range of fire frequencies (3-, 6- and 9-year intervals) over an extended period. We also examined the flowering response in unburnt habitat. High survival rates (>95%) were observed for B. grandiflora plants in heathland that had remained unburnt for a minimum of 30 years. Flowering after experimental burns was found to peak in the second post-fire flowering season rather than the first, and there was no clear fire frequency effect. Maximum levels of flowering during the second post-fire season reached 38 to 56% of individuals, although in some years post-fire flowering during this peak season was as low as 23%. Comparatively few plants flowered during the second-year peak season after every fire, and ~34% of individuals in both the 6- and 9-year burn treatments failed to flower at any time. Inter-fire flowering was also observed, and in some instances this flowering was not significantly different to the level achieved during the peak post-fire flowering season. For example, ~9% of individuals flowered 5–7 times over a 12-year period despite being burnt on only four occasions. Flowering after vernalisation (winter-chilling) was observed in unburnt heathland, and the level of this response was not significantly different to peak post-fire flowering in some years. The findings are examined in the context of evolutionary and habitat processes within a climate change framework. Future studies should focus on the complex interactions between climate, fire and soil for not only B. grandiflora, but more importantly for the diverse assemblage of plant species in wet heathland.

Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

2015 ◽  
Vol 72 (11) ◽  
pp. 1776-1787 ◽  
Author(s):  
Rachel A. Katz ◽  
Mary C. Freeman
Keyword(s):  
Fish Species ◽  
Survival Rates ◽  
Low Flow ◽  
Small Fish ◽  
Severe Drought ◽  
High Survival ◽  
Opposite Pattern ◽  
Flow Variability ◽  
Low Flows ◽  
Local Survival

Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capture–mark–recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%–80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival.

Spinifex–mallee revegetation: implications for restoration after mineral-sands mining in the Murray–Darling Basin

2016 ◽  
Vol 64 (6) ◽  
pp. 547 ◽  
Author(s):  
Ian R. K. Sluiter ◽  
Andrew Schweitzer ◽  
Ralph Mac Nally
Keyword(s):  
Arid Zone ◽  
Eucalyptus Species ◽  
Severe Drought ◽  
Remnant Vegetation ◽  
Spatial Coverage ◽  
Millennium Drought ◽  
Eastern Australia ◽  
Vegetation Class ◽  
Western Victoria

Mineral-sands mining in the semiarid and arid zone of south-eastern Australia is now a widespread disturbance that may adversely affect large areas of remnant vegetation, including mallee (Eucalyptus spp.) with hummock grass or spinifex (Triodia scariosa) understorey. No broad-scale restoration projects have been undertaken to revegetate mallee Eucalyptus species with spinifex. We report on the survivorship and relative importance (spatial coverage) of hand-planted tubestock 10 years after establishment in 2001, which included mallee Eucalyptus, Triodia scariosa, Acacia spp. and Hakea spp. These taxa are the dominant plants in a semiarid dune–swale system on a former mineral-sands mine licence area in semiarid, north-western Victoria. Mean survivorship of tubestock was 0.58 ± 0.04. Spinifex (Triodia scariosa), needlewood (Hakea) and several mallee species (Eucalyptus spp.) survived substantially better than the average of all tubestock-planted species, although Acacia spp. had low survivorships. Although the plantings were undertaken in the early stages of the most severe drought in the instrumental record (the ‘Millennium drought’), several taxa survived well and species such as spinifex established and developed ground coverage greater than the benchmark values for the ecological vegetation class of the location. We conclude that hand-planting of tubestock can achieve restoration objectives for this component of spinifex–mallee vegetation, even under extremely arduous conditions associated with long-term drought. We also herald the importance of taking a long-term view to the assessment of revegetation success, in this case 10 years.

scholarly journals Adaptation of an Invasive Pest to Novel Environments: Life History Traits of Drosophila suzukii in Coastal and Mainland Areas of Greece during Overwintering

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 727
Author(s):  
Stella A. Papanastasiou ◽  
Vasilis G. Rodovitis ◽  
Eleni Verykouki ◽  
Evmorfia P. Bataka ◽  
Nikos T. Papadopoulos
Keyword(s):  
Life History ◽  
Coastal Area ◽  
Life History Traits ◽  
Survival Rates ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Invasive Pest ◽  
High Survival ◽  
Drosophila Suzukii ◽  
The Usa

Drosophila suzukii is a polyphagous pest of small and soft fruit, originating from Asia, which has spread and established in Europe and the USA. Adults exhibit seasonal phenotypes, i.e., summer morphs (SM) and winter morphs (WM) to cope with fluctuating environmental conditions. WM have a darker cuticle and larger wings compared to SM, while WM females experience reproductive dormancy. We studied the life history traits (lifespan, female reproductive status and number of produced offspring) of WM and SM that were exposed to winter field conditions of a coastal and a mainland agricultural area, with mild and cold winter climates, respectively. Mated adults of each phenotype were individually placed in vials bearing nutritional/oviposition substrate, and transferred to the field from November 2019 to May 2020, when the death of the last individual was recorded. Almost all SM females (90%) and no WM female carried mature ovarioles before being transferred to the field. WM exhibited a longer lifespan than SM adjusting for location and sex. Differences in survival between the two phenotypes were more pronounced for adults kept in the mainland area. The majority of SM females produced offspring during overwintering in the mild coastal area, but only a few SM were reproductively active in the cold mainland area. Some WM females produced progeny during overwintering in the mild conditions of the coastal area, but all WM females were in reproductive arrest in the mainland area. Overwintering females in the coastal area had a shorter lifespan and produced more progeny than those kept in the mainland area. High survival rates of WM provide indications of the successful performance of this phenotype in the adverse conditions of the cold climates. Additionally, the continuous reproductive activity of SM females and the onset of progeny production by WM females during overwintering in the coastal area indicate that the insect remains reproductively active throughout the year in areas with mild climatic conditions. Our findings support the successful adaptation of D. suzukii in both areas tested and can be used for the development of area-specific population models, based on the prevailing climatic conditions.

scholarly journals Cognitive decline in patients with prostate cancer: study protocol of a prospective cohort, NEON-PC

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043844
Author(s):  
Natalia Araujo ◽  
Samantha Morais ◽  
Ana Rute Costa ◽  
Raquel Braga ◽  
Ana Filipa Carneiro ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cognitive Decline ◽  
Cognitive Performance ◽  
Androgen Deprivation Therapy ◽  
Survival Rates ◽  
Cardiovascular Complications ◽  
Androgen Deprivation ◽  
High Survival ◽  
The Impact

IntroductionProstate cancer is the most prevalent oncological disease among men in industrialised countries. Despite the high survival rates, treatments are often associated with adverse effects, including metabolic and cardiovascular complications, sexual dysfunction and, to a lesser extent, cognitive decline. This study was primarily designed to evaluate the trajectories of cognitive performance in patients with prostate cancer, and to quantify the impact of the disease and its treatments on the occurrence of cognitive decline.MethodsParticipants will be recruited from two main hospitals providing care to approximately half of the patients with prostate cancer in Northern Portugal (Portuguese Institute of Oncology of Porto and São João Hospital Centre), and will comprise a cohort of recently diagnosed patients with prostate cancer proposed for different treatment plans, including: (1) radical prostatectomy; (2) brachytherapy and/or radiotherapy; (3) radiotherapy in combination with androgen deprivation therapy and (4) androgen deprivation therapy (with or without chemotherapy). Recruitment began in February 2018 and is expected to continue until the first semester of 2021. Follow-up evaluations will be conducted at 1, 3, 5, 7 and 10 years. Sociodemographic, behavioural and clinical characteristics, anxiety and depression, health literacy, health status, quality of life, and sleep quality will be assessed. Blood pressure and anthropometrics will be measured, and a fasting blood sample will be collected. Participants’ cognitive performance will be evaluated before treatments and throughout follow-up (Montreal Cognitive Assessment and Cube Test as well as Brain on Track for remote monitoring). All participants suspected of cognitive impairment will undergo neuropsychological tests and clinical observation by a neurologist.Ethics and disseminationThe study was approved by the Ethics Committee of the hospitals involved. All participants will provide written informed consent, and study procedures will be developed to ensure data protection and confidentiality. Results will be disseminated through publication in peer-reviewed journals and presentation in scientific meetings.

scholarly journals Bone marrow niche crosses paths with BMPs: a road to protection and persistence in CML

2019 ◽  
Vol 47 (5) ◽  
pp. 1307-1325 ◽  
Author(s):  
Caroline Busch ◽  
Helen Wheadon
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Bone Morphogenetic Proteins ◽  
Kinase Inhibitor ◽  
Survival Rates ◽  
High Survival ◽  
Bone Marrow Niche ◽  
Matrix Deposition ◽  
Bmp Receptors ◽  
Number Of Patients

Abstract Chronic myeloid leukaemia (CML) is a paradigm of precision medicine, being one of the first cancers to be treated with targeted therapy. This has revolutionised CML therapy and patient outcome, with high survival rates. However, this now means an ever-increasing number of patients are living with the disease on life-long tyrosine kinase inhibitor (TKI) therapy, with most patients anticipated to have near normal life expectancy. Unfortunately, in a significant number of patients, TKIs are not curative. This low-level disease persistence suggests that despite a molecularly targeted therapeutic approach, there are BCR-ABL1-independent mechanisms exploited to sustain the survival of a small cell population of leukaemic stem cells (LSCs). In CML, LSCs display many features akin to haemopoietic stem cells, namely quiescence, self-renewal and the ability to produce mature progeny, this all occurs through intrinsic and extrinsic signals within the specialised microenvironment of the bone marrow (BM) niche. One important avenue of investigation in CML is how the disease highjacks the BM, thereby remodelling this microenvironment to create a niche, which enables LSC persistence and resistance to TKI treatment. In this review, we explore how changes in growth factor levels, in particular, the bone morphogenetic proteins (BMPs) and pro-inflammatory cytokines, impact on cell behaviour, extracellular matrix deposition and bone remodelling in CML. We also discuss the challenges in targeting LSCs and the potential of dual targeting using combination therapies against BMP receptors and BCR-ABL1.

scholarly journals Survival Rate of 1008 Short Dental Implants with 21 Months of Average Follow-Up: A Retrospective Study

2020 ◽  
Vol 9 (12) ◽  
pp. 3943
Author(s):  
João Caramês ◽  
Ana Catarina Pinto ◽  
Gonçalo Caramês ◽  
Helena Francisco ◽  
Joana Fialho ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Survival Rate ◽  
Dental Implants ◽  
Cox Regression ◽  
Survival Rates ◽  
High Survival ◽  
Implant Survival ◽  
Posterior Maxilla ◽  
Clinical Records

This retrospective study evaluated the survival rate of short, sandblasted acid-etched surfaced implants with 6 and 8 mm lengths with at least 120 days of follow-up. Data concerning patient, implant and surgery characteristics were retrieved from clinical records. Sandblasted and acid-etched (SLA)-surfaced tissue-level 6 mm (TL6) or 8 mm (TL8) implants or bone-level tapered 8 mm (BLT8) implants were used. Absolute and relative frequency distributions were calculated for qualitative variables and mean values and standard deviations for quantitative variables. A Cox regression model was performed to verify whether type, length and/or width influence the implant survival. The cumulative implant survival rate was assessed by time-to-event analyses (Kaplan–Meier estimator). In all, 513 patients with a mean age of 58.00 ± 12.44 years received 1008 dental implants with a mean follow-up of 21.57 ± 10.77 months. Most implants (78.17%) presented a 4.1 mm diameter, and the most frequent indication was a partially edentulous arch (44.15%). The most frequent locations were the posterior mandible (53.97%) and the posterior maxilla (31.55%). No significant differences were found in survival rates between groups of type, length and width of implant with the cumulative rate being 97.7% ± 0.5%. Within the limitations of this study, the evaluated short implants are a predictable option with high survival rates during the follow-up without statistical differences between the appraised types, lengths and widths.

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