scholarly journals Changes in belowground biodiversity during ecosystem development

2019 ◽  
Vol 116 (14) ◽  
pp. 6891-6896 ◽  
Author(s):  
Manuel Delgado-Baquerizo ◽  
Richard D. Bardgett ◽  
Peter M. Vitousek ◽  
Fernando T. Maestre ◽  
Mark A. Williams ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Abiotic Factors ◽  
Plant Cover ◽  
Ecosystem Development ◽  
Productivity Decomposition ◽  
Lower Productivity ◽  
Wide Range ◽  
Ecological Patterns ◽  
Biodiversity Changes ◽  
Globally Distributed

Belowground organisms play critical roles in maintaining multiple ecosystem processes, including plant productivity, decomposition, and nutrient cycling. Despite their importance, however, we have a limited understanding of how and why belowground biodiversity (bacteria, fungi, protists, and invertebrates) may change as soils develop over centuries to millennia (pedogenesis). Moreover, it is unclear whether belowground biodiversity changes during pedogenesis are similar to the patterns observed for aboveground plant diversity. Here we evaluated the roles of resource availability, nutrient stoichiometry, and soil abiotic factors in driving belowground biodiversity across 16 soil chronosequences (from centuries to millennia) spanning a wide range of globally distributed ecosystem types. Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower-productivity ecosystems (i.e., drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (i.e., wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity shares similar ecological drivers as soils and ecosystems develop. In general, temporal changes in aboveground plant diversity and belowground biodiversity were not correlated, challenging the common perception that belowground biodiversity should follow similar patterns to those of plant diversity during ecosystem development. Taken together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally distributed ecosystem types and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia.

Landscape analysis through pictorial transects in degraded lands.

2021 ◽  
Author(s):  
Juan Antonio Campos ◽  
Jaime Villena ◽  
Marta M. Moreno ◽  
Jesús D. Peco ◽  
Mónica Sánchez-Ormeño ◽  
...  
Keyword(s):  
Large Scale ◽  
Fine Particles ◽  
Plant Cover ◽  
Degraded Lands ◽  
Ecological Resources ◽  
Allochthonous Species ◽  
Ecological Patterns ◽  
Good Characterization ◽  
Photosynthetic Potential ◽  
High Degree

<p>Understanding the dynamics of plant populations and their relationship with the characteristics of the terrain (slope, texture, etc.) and with particular phenomena (erosion, pollution, environmental constrains, etc.) that could affect them is crucial in order to manage regeneration and rehabilitation projects in degraded lands. In recent years, the emphasis has been placed on the observation and assessment of microtopographic drivers as they lead to large-scale phenomena. All the ecological variables that affect a given area are interconnected and the success in unraveling the ecological patterns of operation relies on making a good characterization of all the parameters involved.</p><p>It is especially interesting to study the natural colonization processes that take place in Mediterranean areas with a high degree of seasonality, to whose climatic restrictions, the presence of pollutants and various anthropic actions, can be added. Over these degraded areas, we propose using a new tool, what we have come to call "<strong>pictorial transects</strong>", that is, one-dimensional artificial transects built from low-scale photographs (2 m<sup>2</sup>) taken along a line of work (transect) where you can see the points where ecological resources are generated, stored and lost, and their fluctuation throughout time. A derivative of these would be the "<strong>green transects</strong>" in which the green color has been discriminated using the open software Image I. It is an inexpensive, fast and straightforward pictorial method that can be used to research and monitor the spatial and temporal fluctuation of the potential input of resources (organic matter, water, fine particles, etc.) to the ecosystem.</p><p>The information obtained from pictorial transects not only refers to the measurement of the photosynthetic potential per unit area or the location of the critical points (generate, storage or sink of resources) but also makes it possible to monitor the specific composition of the plant cover. For an appropriate use of this methodology, the criteria to determine the direction and length of the different transects must be previously and carefully established according to the objectives proposed in the study. For example: a radial transect in a salty pond will give us information on the changes in the plant cover as we move away from the center and the salinity decreases. In the same pond, a transect parallel to the shore will give us information on those changes that occur in the vegetation that do not depend on the degree of salinity. There are some cases in which this method could be very useful, as in the natural colonization of a degraded mine site or to assess the progression area affected by allochthonous species or weeds in extensive crops.</p>

Effect of Environmental Factors on Germination and Emergence of Shortawn Foxtail (Alopecurus aequalis)

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Ning Zhao ◽  
Qi Li ◽  
Wenlei Guo ◽  
Lele Zhang ◽  
Lu’an Ge ◽  
...  
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Control Strategies ◽  
Abiotic Factors ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Burial Depth ◽  
Effective Measure ◽  
Wide Range

Shortawn foxtail is an invasive grass weed infesting winter wheat and canola production in China. A better understanding of the germination ecology of shortawn foxtail would help to develop better control strategies for this weed. Experiments were conducted under laboratory conditions to evaluate the effects of various abiotic factors, including temperature, light, pH, osmotic stress, salt concentration, and planting depth, on seed germination and seedling emergence of shortawn foxtail. The results showed that the seed germination rate was greater than 90% over a wide range of constant (5 to 25C) and alternating (15/5 to 35/25C) temperatures. Maximum germination occurred at 20C or 25/15C, and no germination occurred at 35C. Light did not appear to have any effect on seed germination. Shortawn foxtail germination was 27% to 99% over a pH range of 4 to 10, and higher germination was obtained at alkaline pH values ranging from 7 to 10. Seed germination was sensitive to osmotic potential and completely inhibited at an osmotic potential of −0.6 MPa, but it was tolerant to salinity: germination even occurred at 200 mM NaCl (5%). Seedling emergence was highest (98%) when seeds were placed on the soil surface but declined with the increasing burial depth. No seedlings emerged when seeds were buried 6-cm deep. Deep tillage could be an effective measure to limit seed germination from increased burial depth. The results of this study will lead to a better understanding of the requirements for shortawn foxtail germination and emergence and will provide information that could contribute to its control.

scholarly journals Temperature as a modulator of sexual selection

2018 ◽  
Author(s):  
Roberto García-Roa ◽  
Francisco Garcia-Gonzalez ◽  
Daniel W.A. Noble ◽  
Pau Carazo
Keyword(s):  
Global Warming ◽  
Sexual Selection ◽  
Thermal Environment ◽  
Abiotic Factors ◽  
Meta Analysis ◽  
Population Viability ◽  
Order Effects ◽  
Secondary Sexual Traits ◽  
Trade Offs ◽  
Wide Range

A central question in ecology and evolution is to understand why sexual selection varies so much in strength across taxa, and it has long been known that ecological factors are crucial to this respect. Temperature is a particularly critical abiotic ecological factor that can drastically modulate a wide range of physiological, morphological and behavioural traits, impacting individuals and populations at a global taxonomic scale. Furthermore, temperature exhibits substantial temporal variation (e.g. daily, seasonally and inter-seasonally), and hence for most species in the wild sexual selection will regularly unfold in a dynamic thermal environment. Unfortunately, studies have so far almost completely neglected the role of temperature as a modulator of sexual selection. Here, we outline the main pathways via which temperature can affect the intensity and form (i.e. mechanisms) of sexual selection, via: a) direct effects on secondary sexual traits and preferences (i.e. trait variance, opportunity for selection and trait-fitness covariance), and b) indirect effects on key mating parameters, sex-specific reproductive costs/benefits, trade-offs, demography and correlated abiotic factors. Building upon this framework, we show that, by focusing exclusively on the first order effects that environmental temperature has on traits linked with individual fitness and population viability, current global warming studies may be ignoring important eco-evolutionary feedbacks mediated by sexual selection. Finally, we tested the general prediction that temperature modulates sexual selection by conducting a meta-analysis of available studies experimentally manipulating temperature and reporting effects on the variance of male/female reproductive success and/or traits under sexual selection. Our results show a clear association between temperature and sexual selection measures in both sexes. In short, we suggest that studying the feedback between temperature and sexual selection processes can be vital to better understand variation in the strength of sexual selection in nature, and its consequences for population viability in response to environmental change (e.g. global warming).

scholarly journals Building a Global System for the Conservation of all Plant Diversity

2016 ◽  
pp. 5-13
Author(s):  
Paul Smith
Keyword(s):  
Plant Species ◽  
Plant Diversity ◽  
Plant Conservation ◽  
Professional Community ◽  
Cost Effective ◽  
Global Network ◽  
Ex Situ ◽  
Botanic Gardens ◽  
Global System ◽  
Wide Range

Botanic gardens and arboreta offer the opportunity to conserve and manage a wide range of plant diversity ex situ, and in situ in the broader landscape. The rationale that botanic gardens have a major role to play in preventing plant species extinctions is based on the assumptions that (1) there is no technical reason why any plant species should become extinct, and (2) that, as a professional community, botanic gardens possess a unique set of skills that encompass finding, identifying, collecting, conserving and growing plant diversity across the entire taxonomic spectrum. Botanic Gardens Conservation International (BGCI) is the pivotal centre of a global network of c. 2,600 botanic gardens and arboreta, which includes living collections representing at least one-third of known plant diversity; world class seed banks, glasshouses and tissue culture infrastructures; and technical knowledge networks covering all aspects of plant conservation. Following the example of the crop conservation community, BGCI is promoting the concept of a cost-effective, rational,botanic garden-centred Global System for the conservation and management of plant diversity.This system will aim to collect, conserve, characterise and cultivate samples from all of the world’s rare and threatened plants as an insurance policy against their extinction in the wild and as a source of plant material for human innovation, adaptation and resilience.

scholarly journals Metagenomic Signatures of Bacterial Adaptation to Life in the Phyllosphere of a Salt-Secreting Desert Tree

2016 ◽  
Vol 82 (9) ◽  
pp. 2854-2861 ◽  
Author(s):  
Omri M. Finkel ◽  
Tom O. Delmont ◽  
Anton F. Post ◽  
Shimshon Belkin
Keyword(s):  
High Salinity ◽  
Stress Factors ◽  
Metagenomic Data ◽  
Metagenomic Sequencing ◽  
Contig Assembly ◽  
Bacterial Populations ◽  
Content Type ◽  
Light Sensing ◽  
Wide Range ◽  
Globally Distributed

ABSTRACTThe leaves ofTamarix aphylla, a globally distributed, salt-secreting desert tree, are dotted with alkaline droplets of high salinity. To successfully inhabit these organic carbon-rich droplets, bacteria need to be adapted to multiple stress factors, including high salinity, high alkalinity, high UV radiation, and periodic desiccation. To identify genes that are important for survival in this harsh habitat, microbial community DNA was extracted from the leaf surfaces of 10Tamarix aphyllatrees along a 350-km longitudinal gradient. Shotgun metagenomic sequencing, contig assembly, and binning yielded 17 genome bins, six of which were >80% complete. These genomic bins, representing three phyla (Proteobacteria,Bacteroidetes, andFirmicutes), were closely related to halophilic and alkaliphilic taxa isolated from aquatic and soil environments. Comparison of these genomic bins to the genomes of their closest relatives revealed functional traits characteristic of bacterial populations inhabiting theTamarixphyllosphere, independent of their taxonomic affiliation. These functions, most notably light-sensing genes, are postulated to represent important adaptations toward colonization of this habitat.IMPORTANCEPlant leaves are an extensive and diverse microbial habitat, forming the main interface between solar energy and the terrestrial biosphere. There are hundreds of thousands of plant species in the world, exhibiting a wide range of morphologies, leaf surface chemistries, and ecological ranges. In order to understand the core adaptations of microorganisms to this habitat, it is important to diversify the type of leaves that are studied. This study provides an analysis of the genomic content of the most abundant bacterial inhabitants of the globally distributed, salt-secreting desert treeTamarix aphylla. Draft genomes of these bacteria were assembled, using the culture-independent technique of assembly and binning of metagenomic data. Analysis of the genomes reveals traits that are important for survival in this habitat, most notably, light-sensing and light utilization genes.

scholarly journals Hybridization between sympatric hammerhead sharks in the western North Atlantic Ocean

2019 ◽  
Vol 15 (4) ◽  
pp. 20190004 ◽  
Author(s):  
Amanda M. Barker ◽  
Douglas H. Adams ◽  
William B. Driggers ◽  
Bryan S. Frazier ◽  
David S. Portnoy
Keyword(s):  
Atlantic Ocean ◽  
First Generation ◽  
North Atlantic Ocean ◽  
Western Atlantic ◽  
Sphyrna Lewini ◽  
Scalloped Hammerhead ◽  
Wide Range ◽  
Hammerhead Sharks ◽  
Conservation Concern ◽  
Globally Distributed

Hybridization between closely related species has been documented across a wide range of taxa but has not been well studied in elasmobranchs. Hammerhead sharks have drawn global conservation concern because they experience some of the highest mortality rates among sharks when interacting with fisheries. Here we report on the detection of hybrids between the globally distributed scalloped hammerhead ( Sphyrna lewini ) and recently described Carolina hammerhead ( S. gilberti ) which are only known from the western Atlantic Ocean. Using a genomics approach, 10 first-generation hybrids and 15–17 backcrosses were detected from 554 individuals. The identification of backcrosses demonstrates hybrids are viable, and all backcrosses but one involved a scalloped hammerhead. All hybrids but one possessed Carolina hammerhead mtDNA, indicating sex-biased gene flow between species. Repeated hybridization and backcrossing with scalloped hammerheads could lead to the loss of endemic Carolina hammerheads.

scholarly journals Relationship between moth (night active Lepidoptera) diversity and vegetation characteristics in southern Sweden

2020 ◽  
Vol 24 (6) ◽  
pp. 1005-1015
Author(s):  
Torbjörn Tyler
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Diversity ◽  
Vascular Plant ◽  
Habitat Characteristics ◽  
Vegetation Composition ◽  
Vascular Plant Diversity ◽  
Site Characteristics ◽  
Tree Canopy Cover ◽  
Wide Range

Abstract The diversity and community composition of moths (both macro- and micromoths) at 32 sites, representing a wide range of habitat types (forests, grasslands, wetlands, agricultural and urban areas) within a restricted region in central Scania, southern-most Sweden, was investigated by use of light moth traps and compared with vascular plant species richness and habitat characteristics. The results revealed a highly significant general association between vegetation composition and the composition of the moth community and multivariate (CCA) analyses indicated light availability and soil fertility parameters (pH and macronutrients) to be the habitat characteristics that best correlated with moth community composition. Less strong, but still significant, positive relationships between moth abundance and local vascular plant diversity were also revealed. Moth species richness was positively correlated with diversity of woody plant genera in the neighborhood, but not with local vascular plant diversity in general. As for more general site characteristics, there were tendencies for higher moth richness and abundance at sites with more productive soils (well-drained, high pH, high nutrient availability), while shading/tree canopy cover, management, soil disturbance regimes and nectar production appeared unrelated to moth community parameters. It is concluded that local moth assemblages are strongly influenced by site characteristics and vegetation composition. Implications for insect conservation: The results show that obtaining moth data on a local scale is useful for conservation planning and does not need to be very cumbersome. Local moth assemblages monitored are indeed related to local site characteristics of conservation relevance.

Plasticity in extended phenotypes: how the antlion Myrmeleon crudelis adjusts the pit traps depending on biotic and abiotic conditions

2019 ◽  
Vol 66 (1-2) ◽  
pp. 41-47 ◽  
Author(s):  
Alejandro G. Farji-Brener ◽  
Sabrina Amador-Vargas
Keyword(s):  
Abiotic Factors ◽  
Plant Cover ◽  
Coarse Grained ◽  
Abiotic Conditions ◽  
Fine Grained ◽  
Fine Soil ◽  
Fine Grained Soil ◽  
Trap Size ◽  
Pit Depth ◽  
Pit Design

Abstract The physical structures built by animals are considered extended phenotypes that reflect how organisms make decisions and deal with changes in their biotic and abiotic environment. We summarize the results of several studies on Myrmeleon crudelis, a neuropteran larva that digs pit-traps in the soil to capture small arthropods (mostly ants) in the tropical dry forests of Costa Rica. Specifically, we showed how this species responds to varying biotic and abiotic conditions with changes in the design and/or location of its pit traps. Several experiments and field comparisons indicate that: 1) antlions adjust the pit design according to the abundance and type of prey. When prey is scarce, antlions increased trap diameter, an architectural adjustment that enhances the probability of prey encounter. Antlions that experienced high prey abundance, but the prey easily escaped, then increased pit depth, an adjustment that increases the chance of prey retention; 2) soil compaction strongly reduced pit-trap size and abundance; 3) antlions preferred soils with high proportion of fine-particle size to build pits. In fine-grained soil, pit-traps are larger and more efficient to capture prey than traps in coarse-grained soils; and 4) pit-traps may also be affected through indirect effects of soil structure and vegetation cover. Areas with fine-soil presented less plant cover, and plant cover could be beneficial for antlions because it acts as a shelter against direct sunlight and rainfall, or it may represent a cost because it is a source of leaflitter falling in the pits. The works summarized here how trap-building predators can exhibit considerable flexibility in trap construction in response to various biotic and abiotic factors, emphasizing how the study of extended phenotypes can be a useful approach to better understand the flexibility of foraging behaviors.

What geckos are – an ecological-biogeographic perspective

2019 ◽  
Vol 66 (3-4) ◽  
pp. 253-263 ◽  
Author(s):  
Shai Meiri
Keyword(s):  
Survival Rates ◽  
Large Degree ◽  
Body Temperatures ◽  
Similar Activity ◽  
Wide Range ◽  
Low Latitudes ◽  
Preferred Temperatures ◽  
Biological Attributes ◽  
Globally Distributed ◽  
Activity Times

Geckos are a hyper-diverse, ancient, and globally distributed group. They have diverged early from other squamates and thus can be expected to differ from them along multiple ecological, life history, and biogeographic axes. I review a wide range of gecko traits, comparing them to those of other lizard taxa, to identify the unique, and unifying, attributes of geckos among lizards, based on comprehensive databases of lizard distributions and biological attributes. Few traits completely separate geckos from other lizard taxa, yet they differ to a large degree along many axes: they are more restricted to low latitudes and altitudes, are especially diverse on islands, but relatively scarce in America. They are small lizards, that lay small, fixed clutch sizes, for which they compensate only partially by laying frequently. Because they mature at relatively similar ages and have similar lifespans to other lizards, geckos produce fewer offspring over a year, and over their lifetimes, perhaps implying that they enjoy higher survival rates. While being the only large lizard clade of predominantly nocturnal lizards a large proportion of species is active by day. Gecko body temperatures and preferred temperatures are lower than those of other lizards –even when they are compared to lizards with similar activity times. Worryingly, most geckos have small ranges that often reside completely outside of protected areas – much more frequently than in other reptile and vertebrate taxa.

scholarly journals Climate mediates the biodiversity–ecosystem stability relationship globally

2018 ◽  
Vol 115 (33) ◽  
pp. 8400-8405 ◽  
Author(s):  
Pablo García-Palacios ◽  
Nicolas Gross ◽  
Juan Gaitán ◽  
Fernando T. Maestre
Keyword(s):  
Plant Diversity ◽  
Plant Biomass ◽  
Leaf Traits ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Ecosystem Stability ◽  
Positive Role ◽  
Insurance Hypothesis ◽  
Wide Range ◽  
Dryland Ecosystems

The insurance hypothesis, stating that biodiversity can increase ecosystem stability, has received wide research and political attention. Recent experiments suggest that climate change can impact how plant diversity influences ecosystem stability, but most evidence of the biodiversity–stability relationship obtained to date comes from local studies performed under a limited set of climatic conditions. Here, we investigate how climate mediates the relationships between plant (taxonomical and functional) diversity and ecosystem stability across the globe. To do so, we coupled 14 years of temporal remote sensing measurements of plant biomass with field surveys of diversity in 123 dryland ecosystems from all continents except Antarctica. Across a wide range of climatic and soil conditions, plant species pools, and locations, we were able to explain 73% of variation in ecosystem stability, measured as the ratio of the temporal mean biomass to the SD. The positive role of plant diversity on ecosystem stability was as important as that of climatic and soil factors. However, we also found a strong climate dependency of the biodiversity–ecosystem stability relationship across our global aridity gradient. Our findings suggest that the diversity of leaf traits may drive ecosystem stability at low aridity levels, whereas species richness may have a greater stabilizing role under the most arid conditions evaluated. Our study highlights that to minimize variations in the temporal delivery of ecosystem services related to plant biomass, functional and taxonomic plant diversity should be particularly promoted under low and high aridity conditions, respectively.

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