scholarly journals A systematic review of the recent ecological literature on cushion plants: champions of plant facilitation

Web Ecology ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 44-49 ◽  
Author(s):  
A. M. Reid ◽  
L. J. Lamarque ◽  
C. J. Lortie
Keyword(s):  
Systematic Review ◽  
Plant Species ◽  
Focal Point ◽  
Environmental Gradients ◽  
Keystone Species ◽  
Arid Environments ◽  
Ecological Research ◽  
Cushion Plant ◽  
Cushion Plants ◽  
Number Of Publications

Abstract. Cushion-forming plant species are found in alpine and polar environments around the world. They modify the microclimate, thereby facilitating other plant species. Similar to the effectiveness of shrubs as a means to study facilitation in arid and semi-arid environments, we explore the potential for cushion plant species to expand the generality of research on this contemporary ecological interaction. A systematic review was conducted to determine the number of publications and citation frequency on relevant ecological topics whilst using shrub literature as a baseline to assess relative importance of cushions as a focal point for future ecological research. Although there are forty times more shrub articles, mean citations per paper is comparable between cushion and shrub literature. Furthermore, the scope of ecological research topics studied using cushions is broad including facilitation, competition, environmental gradients, life history, genetics, reproduction, community, ecosystem and evolution. The preliminary ecological evidence to date also strongly suggests that cushion plants can be keystone species in their ecosystems. Hence, ecological research on net interactions including facilitation and patterns of diversity can be successfully examined using cushion plants, and this is particularly timely given expectations associated with a changing climate in these regions.

scholarly journals Species interactions involving cushion plants in high-elevation environments under a changing climate

Ecosistemas ◽  
2021 ◽  
Vol 30 (1) ◽  
pp. 2186
Author(s):  
Francisco I. Pugnaire ◽  
Gianalberto Losapio ◽  
Christian Schöb
Keyword(s):  
Global Warming ◽  
Plant Species ◽  
Species Interactions ◽  
High Elevation ◽  
Plant Ecology ◽  
Plant Interactions ◽  
Mountain Ranges ◽  
Cushion Plant ◽  
Cushion Plants ◽  
Negative Impacts

The effects of global warming are stronger in high-elevation environments than elsewhere. Here, we review recent advances in alpine plant ecology with a focus on dry mountain ranges, mainly in Mediterranean-type climate, with a global change perspective. Raising temperatures and changes in precipitation influence both plant growth and reproduction, and therefore the spatial distribution of species. Research in high-elevation systems evidenced that plant–plant interactions involving cushion plants play a crucial role in the assembly of plant communities, influencing species richness, genetic and phylogenetic diversity, and species persistence. By buffering environmental extremes and ameliorating biophysical conditions, cushion plant species acting as ecosystem engineers are fundamental in the response of alpine ecosystems to global warming, mitigating negative impacts on different plant species with narrow niche and small distribution range.

Reciprocal gender effects of a keystone alpine plant species on other plants, pollinators, and arthropods

Botany ◽  
2012 ◽  
Vol 90 (4) ◽  
pp. 273-282 ◽  
Author(s):  
Christopher J. Lortie ◽  
Anya M. Reid
Keyword(s):  
Sexual Dimorphism ◽  
Plant Species ◽  
Reproductive Output ◽  
Trophic Levels ◽  
Gender Effects ◽  
Positive Interactions ◽  
Plant Interactions ◽  
General Hypothesis ◽  
Cushion Plant ◽  
Cushion Plants

The term facilitation generally describes positive interactions between plants, and a common approach in these studies is to identify a dominant plant to structure sampling. Unfortunately, whilst this field has rapidly expanded community ecology, it rarely includes other trophic levels such as insects and pollinators. Here, we combine facilitation, pollination, and reciprocity measures to explore the general hypothesis that sexual dimorphism in a benefactor plant species mediates its impact. The following three predictions were tested and supported using the gynodioecious alpine cushion plant Silene acaulis (L.) Jacq.: (i) that the trait set of a gynodioecious benefactor plant varies between genders; (ii) that dimorphism changes the facilitation of other plants, arthropods, and pollinators; and (iii) that insect selectivity, particularly pollinators, reciprocally impacts the reproductive output of the two genders. Female S. acaulis cushion plants produced significantly more flowers but they were smaller than those of hermaphrodites. Hermaphrodite cushions facilitated other plant species and pollinators more effectively than females, whilst females strongly facilitated more arthropods. Finally, female plants have significantly higher reproductive output as estimated by fruit and seed production, and this was directly related to visitation rate by pollinators. Hence, this study clearly establishes the value of combining some of the common themes of pollination biology such as sexual dimorphism, floral morphology, and measuring reproduction with the study of positive plant–plant interactions.

scholarly journals Oil Pollution Affects the Central Metabolism of Keystone Vachellia (Acacia) Trees

2021 ◽  
Vol 13 (12) ◽  
pp. 6660
Author(s):  
Marco Ferrante ◽  
Anuma Dangol ◽  
Shoshana Didi-Cohen ◽  
Gidon Winters ◽  
Vered Tzin ◽  
...  
Keyword(s):  
Oil Spills ◽  
Oil Pollution ◽  
Keystone Species ◽  
Desert Ecosystem ◽  
Arid Environments ◽  
Central Metabolism ◽  
Adult Trees ◽  
Metabolite Profiles ◽  
One Year

Vachellia (formerly Acacia) trees are native to arid environments in Africa and the Arabian Peninsula, where they often support the local animal and plant communities acting as keystone species. The aim of this study was to examine whether oil pollution affected the central metabolism of the native keystone trees Vachellia tortilis (Forssk.) and V. raddiana (Savi), as either adults or seedlings. The study was conducted in the Evrona Nature Reserve, a desert ecosystem in southern Israel where two major oil spills occurred in 1975 and in 2014. Leaf samples were collected to analyze the central metabolite profiles from oil-polluted and unpolluted adult trees and from Vachellia seedlings growing in oil-polluted and unpolluted soils in an outdoor setup. We found that oil pollution had a stronger effect on one-year-old seedlings than on adult trees, reducing the levels of amino acids, sugars, and organic acids. While adult trees are mildly affected by oil pollution, the effects on young seedlings can cause a long-term reduction in the population of these keystone desert trees, ultimately threatening this entire ecosystem.

scholarly journals Effects of Alternative Assessment in EFL Classroom: A Systematic Review

2020 ◽  
Vol 3 (2) ◽  
pp. 7-18
Author(s):  
Wali Khan Monib ◽  
Abdul Qudos Karimi ◽  
Nazifullah Nijat
Keyword(s):  
Systematic Review ◽  
Language Learning ◽  
Alternative Assessment ◽  
Focal Point ◽  
Empirical Studies ◽  
Inclusion Criteria ◽  
Online Search ◽  
Learning Skills ◽  
Positive Effects ◽  
Efl Context

Alternative assessment has been the focus of many educational researches in EFL classroom. This study was carried out to highlight the definition, characteristics and effects of alternative assessment in EFL context by reviewing current research on assessment. The research consisted of a systematic review of the empirical studies on alternative assessment in EFL classroom. Focusing solely on online search, many studies were found but only (n=24) met the inclusion criteria involving a total of (n=1588) participants. Also, it aimed to scrutinize the methods, participants and findings of the selected studies as well as the locations where they were conducted. The findings indicated that most of the studies (18 out of 24) reported positive effects of employing alternative assessment on language learning skills in EFL classroom. The results also show that the dominant method employed in the articles was quantitative where students were the main focal point involved in the research as their participants. The study is further concluded with a discussion on definition, characteristics and effects of alternative assessment in EFL context.

scholarly journals La paradoja de mezquites (Prosopis spp.): La invasión de especies o potenciadores de la biodiversidad?

2017 ◽  
pp. 23 ◽  
Author(s):  
Jordan Golubov ◽  
María C. Mandujano ◽  
Luis E. Eguiarte
Keyword(s):  
Keystone Species ◽  
Arid Environments ◽  
Perennial Species ◽  
Semiarid Environments ◽  
High Species Diversity ◽  
Ecological Importance ◽  
Associated Species ◽  
Semi Arid ◽  
Arid And Semiarid

Arid and semi-arid environments contain relatively high species diversity and are subject to intense use, in particular extensive cattle grazing. The expansion of perennial species in to the grasslands decreases the value of the rangeland, because it makes necessary to control the shrubs, which is not practical in the long term. This paper is a bibliographic review of the ecological importance of the Prosopis (mequite) genus. We compiled information on all the species associated to mesquite (ca. 208 genera and 600 species from different taxa) and we propase that it is important to conserve the mesquites in order to maintain the diversity of the other associated species. We also stress the importance of mesquite as a keystone species in the balance of nitrogen and carbon in the arid and semiarid environments soils. We conclude that the conservation of the mesquites is very relevant, in particular in areas where people want to remove them and convert the environment to grasslands.

scholarly journals Quantifying TB transmission: a systematic review of reproduction number and serial interval estimates for tuberculosis

2018 ◽  
Vol 146 (12) ◽  
pp. 1478-1494 ◽  
Author(s):  
Y. Ma ◽  
C. R. Horsburgh ◽  
L. F. White ◽  
H. E. Jenkins
Keyword(s):  
Systematic Review ◽  
Parameter Estimation ◽  
The Netherlands ◽  
Cause Of Death ◽  
Reproduction Number ◽  
Reproductive Number ◽  
Interval Estimates ◽  
Transmission Parameters ◽  
Serial Interval ◽  
Number Of Publications

AbstractTuberculosis (TB) is the leading global infectious cause of death. Understanding TB transmission is critical to creating policies and monitoring the disease with the end goal of TB elimination. To our knowledge, there has been no systematic review of key transmission parameters for TB. We carried out a systematic review of the published literature to identify studies estimating either of the two key TB transmission parameters: the serial interval (SI) and the reproductive number. We identified five publications that estimated the SI and 56 publications that estimated the reproductive number. The SI estimates from four studies were: 0.57, 1.42, 1.44 and 1.65 years; the fifth paper presented age-specific estimates ranging from 20 to 30 years (for infants <1 year old) to <5 years (for adults). The reproductive number estimates ranged from 0.24 in the Netherlands (during 1933–2007) to 4.3 in China in 2012. We found a limited number of publications and many high TB burden settings were not represented. Certain features of TB dynamics, such as slow transmission, complicated parameter estimation, require novel methods. Additional efforts to estimate these parameters for TB are needed so that we can monitor and evaluate interventions designed to achieve TB elimination.

scholarly journals Evolutionary origins for ecological patterns in space

2020 ◽  
Vol 117 (30) ◽  
pp. 17482-17490 ◽  
Author(s):  
Mark C. Urban ◽  
Sharon Y. Strauss ◽  
Fanie Pelletier ◽  
Eric P. Palkovacs ◽  
Mathew A. Leibold ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Keystone Species ◽  
Future Research ◽  
Evolutionary Divergence ◽  
Patch Selection ◽  
Fully Integrated ◽  
Evolutionary Origins ◽  
Ecological Patterns

Historically, many biologists assumed that evolution and ecology acted independently because evolution occurred over distances too great to influence most ecological patterns. Today, evidence indicates that evolution can operate over a range of spatial scales, including fine spatial scales. Thus, evolutionary divergence across space might frequently interact with the mechanisms that also determine spatial ecological patterns. Here, we synthesize insights from 500 eco-evolutionary studies and develop a predictive framework that seeks to understand whether and when evolution amplifies, dampens, or creates ecological patterns. We demonstrate that local adaptation can alter everything from spatial variation in population abundances to ecosystem properties. We uncover 14 mechanisms that can mediate the outcome of evolution on spatial ecological patterns. Sometimes, evolution amplifies environmental variation, especially when selection enhances resource uptake or patch selection. The local evolution of foundation or keystone species can create ecological patterns where none existed originally. However, most often, we find that evolution dampens existing environmental gradients, because local adaptation evens out fitness across environments and thus counteracts the variation in associated ecological patterns. Consequently, evolution generally smooths out the underlying heterogeneity in nature, making the world appear less ragged than it would be in the absence of evolution. We end by highlighting the future research needed to inform a fully integrated and predictive biology that accounts for eco-evolutionary interactions in both space and time.

scholarly journals Effects of hydrogel amendment on water storage of sandy loam and loam soils and seedling growth of barley, wheat and chickpea

2011 ◽  
Vol 50 (No. 10) ◽  
pp. 463-469 ◽  
Author(s):  
J. Akhter ◽  
K. Mahmood ◽  
K.A. Malik ◽  
A. Mardan ◽  
M. Ahmad ◽  
...  
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Seedling Growth ◽  
Sandy Loam ◽  
Field Capacity ◽  
Water Retention Capacity ◽  
Arid Environments ◽  
Hordeum Vulgare L ◽  
Retention Capacity ◽  
Available Water

The hydrogel amendments may improve seedling growth and establishment by increasing water retention capacity of soils and regulating the plants available water supplies, particularly under arid environments. The effects of different levels of a locally prepared hydrogel were studied on the moisture properties of sandy loam and loam soils (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA, Luvic Yermosol, FAO) and on growth response of three plant species, viz. barley (Hordeum vulgare L.), wheat (Triticum aestivum L.) and chickpea (Cicer arietinum L.). Water absorption by gel was rapid and highest in distilled water and was inhibited by an increase in water salinity. The addition of 0.1, 0.2 and 0.3% hydrogel increased the moisture retention (&theta;r) at field capacity linearly (r = 0.988) and thus the amount of plant available water significantly in both sandy loam and loam soils compared to the untreated soils. Seed germination of wheat and barley was not affected but seedling growth of both species was improved by the gel amendment. In loam soil, seed germination of chickpea was higher with 0.2% gel and seedling growth increased with increase in gel level compared with control conditions. The hydrogel amendment caused a delay by 4&ndash;5 days in wilting of seedlings grown in both soils compared with control conditions. The hydrogel amendment was effective in improving soil moisture availability and thus increased plant establishment. However, the varied responses of plant species in sandy loam and loam soils warrant further studies on the behaviour of different soil types with gel amendments.

scholarly journals Myxospermous seed-mucilage quantity correlates with environmental gradients indicative of water-deficit stress: Plantago species as a model

2019 ◽  
Vol 446 (1-2) ◽  
pp. 343-356 ◽  
Author(s):  
António Teixeira ◽  
Pietro Iannetta ◽  
Kirsty Binnie ◽  
Tracy A. Valentine ◽  
Peter Toorop
Keyword(s):  
Seed Germination ◽  
Water Deficit ◽  
Stress Responses ◽  
Environmental Gradients ◽  
Seedling Survival ◽  
Water Deficit Stress ◽  
Arid Environments ◽  
Seedling Mortality ◽  
The Relationship ◽  
Seed Mucilage

Abstract Aims Myxospermous seed mucilage is multifunctional and is often found in seeds (or achenes) of species occupying arid environments where the trait may influence seed-dispersal and -germination of seeds. The seed mucilage may also enhance soil-water retention, −hydraulic conductivity and -stability. However, the relationship between seed mucilage quantity, seed germination and seedling traits across environmental gradients which determine water-deficit stress has not yet been ascertained. Methods Therefore, we characterised and tested the relationship between seed mucilage quantity, water-deficit stress responses of seeds and seedlings of 36 accessions of four different Plantago species (P. albicans L., P. coronopus L., P. lagopus L. and P. anceolata L.). These were gathered from six regions across Europe, which presented environmental gradients (of rainfall and temperature), and varying soil qualities. Results Seed mucilage was significantly greater in seeds of accessions experiencing: highest summer temperatures; lowest summer precipitation; soils of the same warm dry regions which had greater capacity to retain water within narrow pore spaces. Under water-deficit stress, seeds with most mucilage exhibited a lower base water potential for germination, suffered least seedling mortality and exhibited the most successful seedling development. Conclusions The findings indicate that seed mucilage quantity appeared as an ‘adaptive’ trait and there is a relationship between seed-mucilage quantity, seed germination plus seedling survival and development under environmental conditions of highest water-deficit stress.

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