scholarly journals Coordinated shifts in allocation among reproductive tissues across 14 coexisting plant species

2017 ◽  
Author(s):  
E. H. Wenk ◽  
K. Abramowicz ◽  
M. Westoby ◽  
D. S. Falster
Keyword(s):  
Plant Species ◽  
Seed Size ◽  
Strong Support ◽  
Fruit Production ◽  
Construction Costs ◽  
Suitable Alternative ◽  
Reproductive Tissues ◽  
Energy Flows ◽  
Trade Offs ◽  
Eastern Australia

AbstractPlant species differ in the amounts of energy allocated to different reproductive tissues, driving differences in their ecology and energy flows within ecosystems. While it is widely agreed that energy allocation is key to reproductive outcomes, few studies have estimated how reproductive effort (RE) is partitioned among different pools, for multiple species in a community. In plants, RE can be partitioned in several meaningful ways: seed versus non-seed tissues; into flowers that form seeds and those that fail to develop; into pre-versus post-pollination tissues, and into successful versus aborted ovules. Evolutionary theory suggests several hypotheses about how these tissues should be coordinated across species. To quantify variation in allocation to different reproductive tissues, we collected detailed RE measurements for a year from 14 perennial species in a recurrent-fire coastal heath community in eastern Australia. Overall we found that total accessory costs – the proportion of RE not directly invested in provisioning the seed – were very large, varying from 95.8% to 99.8% across the study species. These results suggest that studies using seed or fruit production as measures of RE may underestimate it by 10-to 500-fold. We propose a suitable alternative that well-approximates true RE. When comparing species, we found strong support for three evolutionary trade-offs that are predicted to arise when a given energy pool is divided into different tissue masses and counts across species: 1) between successful pollen-attraction costs and mature ovule count, 2) between total reproductive costs and seed count, and 3) between seedset and relative investment in pollen-attraction costs. As a result of these trade-offs, species were also predicted to show coordinated shifts in the amounts invested in floral construction, in seedset and seed size. These shifts in investment were indeed observed, with the amount allocated to discarded tissues increasing with seed size and the amount allocated to pollen-attraction decreasing with seed size. It is already well-established that the seed size axis aligns with the colonization-competition life history spectrum; here we show that relative construction costs of pollen-attraction versus provisioning tissues and seedset are also part of this trajectory, expanding our understanding of the relatives sizes of floral and fruiting structures observed across angiosperms.

Predicting the effect of immunocontraceptive recombinant murine cytomegalovirus on population outbreaks of house mice (Mus musculus domesticus) in mallee wheatlands

2005 ◽  
Vol 32 (7) ◽  
pp. 631 ◽  
Author(s):  
A. D. Arthur ◽  
R. P. Pech ◽  
G. R. Singleton
Keyword(s):  
Transmission Rate ◽  
Strong Support ◽  
Murine Cytomegalovirus ◽  
House Mice ◽  
Single Strain ◽  
Mouse Population ◽  
Trade Offs ◽  
Eastern Australia ◽  
Population Outbreak ◽  
Successful Control

Virally vectored immunocontraception using a modified murine cytomegalovirus (MCMV) is being developed for the control of house mice in Australia. In this paper, we develop disease–host models using a combination of laboratory and field data. We then combine these models with a model of a previous mouse population outbreak to explore the likely effectiveness of modified MCMV for controlling mice. Models of homogeneous mixing with and without vertical/pseudovertical transmission provided reasonable fits to field serological data collected during the onset and development of a mouse population outbreak in south-eastern Australia. Both models include the high transmission rate of MCMV suggested by the data. We found no strong support for non-linear contact rates or heterogeneous mixing. When applied to a past outbreak of mice both models gave similar results and suggested that immunocontraceptive MCMV could be effective at reducing agricultural damage to acceptable levels. Successful control was still possible when lags in the development of infertility of up to 10 weeks were added to the model, provided high levels of infertility were achieved. These lags were added because mice can become pregnant just before becoming infertile – the resultant litter would not emerge for 6–7 weeks. Trade-offs between two parameters that could be altered by engineering strains of MCMV – the level of infertility in infected mice and the virus transmission rate – were explored and suggest that a variety of parameter combinations could produce successful control. Our results are encouraging for the future development of virally vectored immunocontraception control of house mice, but future work will need to consider some of the assumptions of these single-strain models.

scholarly journals Niches, rather than neutrality, structure a grassland pioneer guild

2005 ◽  
Vol 272 (1570) ◽  
pp. 1357-1364 ◽  
Author(s):  
Lindsay A Turnbull ◽  
Liz Manley ◽  
Mark Rees
Keyword(s):  
Seed Size ◽  
Adult Stage ◽  
Niche Differentiation ◽  
Competitive Dynamics ◽  
Similar Species ◽  
Adult Density ◽  
Pioneer Species ◽  
Trade Offs ◽  
Very High ◽  
Early Establishment

Pioneer species are fast-growing, short-lived gap exploiters. They are prime candidates for neutral dynamics because they contain ecologically similar species whose low adult density is likely to cause widespread recruitment limitation, which slows competitive dynamics. However, many pioneer guilds appear to be differentiated according to seed size. In this paper, we compare predictions from a neutral model of community structure with three niche-based models in which trade-offs involving seed size form the basis of niche differentiation. We test these predictions using sowing experiments with a guild of seven pioneer species from chalk grassland. We find strong evidence for niche structure based on seed size: specifically large-seeded species produce fewer seeds but have a greater chance of establishing on a per-seed basis. Their advantage in establishment arises because there are more microsites suitable for their germination and early establishment and not directly through competition with other seedlings. In fact, seedling densities of all species were equally suppressed by the addition of competitors' seeds. By the adult stage, despite using very high sowing densities, there were no detectable effects of interspecific competition on any species. The lack of interspecific effects indicates that niche differentiation, rather than neutrality, prevails.

scholarly journals Improving the knowledge of plant potential biodiversity-ecosystem services links using maps at the regional level in Southern Patagonia

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yamina Micaela Rosas ◽  
Pablo L. Peri ◽  
María Vanessa Lencinas ◽  
Romina Lasagno ◽  
Guillermo J. Martínez Pastur
Keyword(s):  
Ecosystem Services ◽  
Plant Species ◽  
Vegetation Index ◽  
Vascular Plant ◽  
Conservation Strategies ◽  
Cultural Ecosystem Services ◽  
Important Indicator ◽  
Ecological Requirements ◽  
Trade Offs ◽  
Southern Patagonia

Abstract Background Biodiversity supports multiple ecosystem services, whereas species loss endangers the provision of many services and affects ecosystem resilience and resistance capacity. The increase of remote sensing techniques allows to estimate biodiversity and ecosystem services supply at the landscape level in areas with low available data (e.g. Southern Patagonia). This paper evaluates the potential biodiversity and how it links with ecosystem services, based on vascular plant species across eight ecological areas. We also evaluated the habitat plant requirements and their relation with natural gradients. A total of 977 plots were used to develop habitat suitability maps based on an environmental niche factor analysis of 15 more important indicator species for each ecological area (n = 53 species) using 40 explanatory variables. Finally, these maps were combined into a single potential biodiversity map, which was linked with environmental variables and ecosystem services supply. For comparisons, data were extracted and compared through analyses of variance. Results The plant habitat requirements varied greatly among the different ecological areas, and it was possible to define groups according to its specialization and marginality indexes. The potential biodiversity map allowed us to detect coldspots in the western mountains and hotspots in southern and eastern areas. Higher biodiversity was associated to higher temperatures and normalized difference vegetation index, while lower biodiversity was related to elevation and rainfall. Potential biodiversity was closely associated with supporting and provisioning ecosystem services in shrublands and grasslands in the humid steppe, while the lowest values were related to cultural ecosystem services in Nothofagus forests. Conclusions The present study showed that plant species present remarkable differences in spatial distributions and ecological requirements, being a useful proxy for potential biodiversity modelling. Potential biodiversity values change across ecological areas allowing to identify hotspots and coldspots, a useful tool for landscape management and conservation strategies. In addition, links with ecosystem services detect potential synergies and trade-offs, where areas with the lowest potential biodiversity are related to cultural ecosystem services (e.g. aesthetic values) and areas with the greatest potential biodiversity showed threats related to productive activities (e.g. livestock).

Reproductive success of wind, generalist, and specialist pollinated plant species following wildfire in desert landscapes

2017 ◽  
Vol 26 (12) ◽  
pp. 1030 ◽  
Author(s):  
Andrew H. Lybbert ◽  
Justin Taylor ◽  
Alysa DeFranco ◽  
Samuel B. St Clair
Keyword(s):  
Reproductive Success ◽  
Plant Species ◽  
Mojave Desert ◽  
Fruit Production ◽  
Native Plant ◽  
Pollination Services ◽  
Generalist Species ◽  
Plant Reproductive Success ◽  
Show Evidence ◽  
Specialist Species

Wildfire can drastically affect plant sexual reproductive success in plant–pollinator systems. We assessed plant reproductive success of wind, generalist and specialist pollinated plant species along paired unburned, burned-edge and burned-interior locations of large wildfires in the Mojave Desert. Flower production of wind and generalist pollinated plants was greater in burned landscapes than adjacent unburned areas, whereas specialist species responses were more neutral. Fruit production of generalist species was greater in burned landscapes than in unburned areas, whereas fruit production of wind- and specialist-pollinated species showed no difference in burned and unburned landscapes. Plants surviving in wildfire-disturbed landscapes did not show evidence of pollination failure, as measured by fruit set and seed:ovule ratios. Generalist- and specialist-plant species established in the interior of burned landscapes showed no difference in fruit production than plants established on burned edges suggesting that pollination services are conserved with increasing distance from fire boundaries in burned desert landscapes. Stimulation of plant reproduction in burned environments due to competition release may contribute to the maintenance of pollinator services and re-establishment of the native plant community in post-fire desert environments.

Optimising canola establishment and yield in south-eastern Australia with hybrids and large seed

2016 ◽  
Vol 67 (4) ◽  
pp. 409 ◽  
Author(s):  
R. D. Brill ◽  
M. L. Jenkins ◽  
M. J. Gardner ◽  
J. M. Lilley ◽  
B. A. Orchard
Keyword(s):  
Grain Yield ◽  
Seed Size ◽  
Biomass Accumulation ◽  
Simulation Modelling ◽  
Sowing Depth ◽  
Large Seed ◽  
South Wales ◽  
Eastern Australia ◽  
Series Of Experiments ◽  
Seed Characteristics

April sowing of canola is considered optimal for grain yield in many regions of Australia; however, there is often insufficient rainfall in April to sow seed into moisture at the ideal depth of 15–30 mm. We report a series of experiments that investigated the seed characteristics (cultivar type and seed size) that would facilitate successful canola emergence from relatively deep sowing (>30 mm). Ten canola cultivar by sowing depth experiments, each with three hybrid and three open-pollinated cultivars, found hybrid cultivars were able to maintain higher emergence rates and grain yield compared with open-pollinated cultivars from deep sowing. Further investigations in the glasshouse showed that the emergence advantage of the hybrid cultivars was largely due to their inherently large seed size, as increased seed size also improved emergence of open-pollinated canola. Early biomass accumulation also improved with larger seeds. In a field experiment, larger seed size of both hybrid and open-pollinated canola increased early biomass accumulation and final grain yield. Simulation modelling in New South Wales demonstrated the importance of timely sowing of canola, as delayed sowing caused a larger reduction in grain yield than reduced plant population. Although ‘moisture-seeking’ (placing seed into moist soil below a layer of dry soil) reduced the emergence rate of canola, the reduction could be offset by planting large seed (>2 mm diameter). This practice of ‘moisture-seeking’ large-seeded canola should be considered as a strategy to improve the timeliness of establishment and subsequent grain yield of canola when rainfall for crop establishment is marginal yet there is moisture available deeper in the seedbed.

Robust modelling to address UPH19 to predict future hydrological responses for water resources adaptation under climate change

2021 ◽  
Author(s):  
Francis Chiew ◽  
Hongxing Zheng ◽  
Jai Vaze
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Accurate Estimate ◽  
Severe Drought ◽  
Hydrological Models ◽  
Adaptation To Climate Change ◽  
Projected Range ◽  
Trade Offs ◽  
Eastern Australia ◽  
Robust Modelling

<p>This paper addresses the implications of UPH19 in extrapolating hydrological models to predict the future and assessing water resources adaptation to climate change. Many studies have now shown that traditional application of hydrological models calibrated against past observations will underestimate the range in the projected future hydrological impact, that is, it will underestimate the decline in runoff where a runoff decrease is projected, and underestimate the increase in runoff where a runoff increase is projected. This study opportunistically uses data from south-eastern Australia which recently experienced a long and severe drought lasting more than ten years and subsequent partial hydrological recovery from the drought. The paper shows that a more robust calibration of rainfall-runoff models to produce good calibration metrics in both the dry periods and wet periods, at the expense of the best calibration over the entire data period, can produce a more accurate estimate of the uncertainty in the projected future runoff, but cannot entirely eliminate the modelling limitation of underestimating the projected range in future runoff. This is because of the need to consider trade-offs between the calibration objectives, particularly in simulating the dry periods, versus enhanced bias that results from the consideration. Hydrological models must therefore also need to be adapted to reflect the non-stationary nature of catchment and vegetation responses in a changing climate under warmer conditions, higher CO<sub>2</sub> and changed precipitation patterns. This is an active area of research in UPH19, and some ideas relevant to this region will be presented.</p>

scholarly journals Screening of Plants Used as Traditional Anticancer Remedies in Mkuranga and Same Districts, Tanzania, Using Brine Shrimp Toxicity Bioassay

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Daniel Z. Matata ◽  
Olipa D. Ngassapa ◽  
Francis Machumi ◽  
Mainen J. Moshi
Keyword(s):  
Plant Species ◽  
Brine Shrimp ◽  
Health Care Services ◽  
Literature Search ◽  
Strong Support ◽  
Preliminary Evaluation ◽  
Contributing Factors ◽  
Anticancer Compounds ◽  
Care Services ◽  
Brine Shrimp Toxicity

Background.Inadequate specialized cancer hospitals and high costs are contributing factors that delay cancer patients from accessing health care services in Tanzania. Consequently, majority of patients are first seen by Traditional Health Practitioners (THPs) before they access specialized services. This study presents ethnomedical information and preliminary evaluation of 25 plant species claimed by THPs in Mkuranga and Same districts of Tanzania on use for treatment of cancer. Literature search and laboratory investigation results are presented to support evaluation.Methods. This study was a single disease ethnomedical enquiry focusing on plants being used for cancer treatment.Face-to-face interviews and questionnaires were administered toeight (8) THPsin Mkuranga and Same districts on the claimed plants and their use for management of cancer. Plants were selected based on being frequently mentioned and emphasis given by THPs. Literature search and brine shrimp toxicity (BST) of methanol : dichloromethane (1:1) extracts was used as surrogates to evaluate strength of the claims.Results.This study reports 25 plant species used by the THPs in two districts of Tanzania. Eight plants (32%) have been reported in the literature to have activity against cancer cells. BST results revealed, 14 (56%) plants exhibited high toxicity against brine shrimps. The most active plants includedCroton pseudopulchellusPax (LC504.2μg/ml),Dalbergia melanoxylonGuill. & Perr. (LC506.8μg/ml),Loranthus micranthusLinn (LC504.0μg/ml),Ochna mossambicensisKlotzsch (LC503.3μg/ml), andSpirostachys africanaSond. (LC504.4μg/ml); their toxicity was comparable to that ofCatharanthus roseus(L) G. Don. (LC506.7μg/ml), an established source of anticancer compounds. Nine other plants had LC50values between (19.8 and 71.6)μg/ml, indicating also potential to yield anticancer.Conclusion.Literature search and BST results provide a strong support of the potential of the claimed plants to yield active anticancer compounds.

Morphological, phytochemical and molecular analyses define species limits in Eucalyptus magnificata (Myrtaceae) and lead to the discovery of a new rare species

2019 ◽  
Author(s):  
Timothy L. Collins ◽  
Rose L. Andrew ◽  
Jeremy J. Bruhl
Keyword(s):  
New England ◽  
Conservation Status ◽  
Strong Support ◽  
Full Description ◽  
Species Limits ◽  
Single Nucleotide ◽  
Test Species ◽  
Field Collection ◽  
Snp Data ◽  
Eastern Australia

Abstract. Eucalyptus magnificata L.A.S.Johnson & K.D.Hill is an endangered species endemic to the New England Tablelands Bioregion of eastern Australia, with taxonomic conflict regarding its recognition. Analyses of morphology, phytochemistry and genomic DNA were used to test species limits of E. magnificata. Morphometric and phytochemical phenetic analyses found distinct differences among E. magnificata, E. baueriana and a putative entity recognised during field collection, i.e. E. sp. Dalveen. Another putative entity, E. sp. Oxley, was morphologically and phytochemically intermediate between E. magnificata and E. conica. Phenetic analysis of single-nucleotide polymorphism (SNP) data supported the results from morphological and phytochemical analyses. The original circumscription of E. magnificata, as distinct from E. baueriana, was strongly corroborated. Eucalyptus magnificata was found to be restricted in distribution to the Macleay Gorges area south-east of Armidale. Multiple lines of evidence provided strong support for the recognition of E. sp. Dalveen as a separately evolving entity at a species level, here described as Eucalyptus dalveenica T.L.Collins, R.L.Andrew & J.J.Bruhl. A full description of the new species, a table distinguishing E. dalveenica from closely related taxa, and an identification key are provided. Distribution, habitat and conservation status are discussed.

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