scholarly journals South American and African Grass Species Cope Differently With Soil Water Availability

2019 ◽  
Vol 11 (13) ◽  
pp. 64
Author(s):  
Carolina Musso ◽  
Glória Pinto ◽  
Heloisa Sinatora Miranda ◽  
Rhaul Oliveira ◽  
Carlos Correia ◽  
...  
Keyword(s):  
Invasive Species ◽  
Soil Moisture ◽  
Water Availability ◽  
Native Species ◽  
Leaf Gas Exchange ◽  
Biomass Accumulation ◽  
Grass Species ◽  
Climate Control ◽  
Shoot Height ◽  
Melinis Minutiflora

African grasses pose a serious threat to the integrity and conservation of the Cerrado biome (Brazilian savanna). This study evaluated the responses of an invasive (Melinis minutiflora) and a native (Schizachyrium microstachyum) grass species to water availability, simulating natural situations. Individuals of the two species were submitted to different soil moisture levels, simulating from drought to flood, for four weeks in a climate-control chamber. Several morphological and physiological parameters were assessed: shoot height, biomass, number of leaves, tillers, leaf area, leaf gas exchange and chlorophylla fluorescence parameters, photosynthetic pigments and MDA concentration and GST, G-POX, APX and CAT activities. Significant differences were observed between species and among soil moisture levels, being drought more detrimental to both. Although both species were able to cope with water stress conditions and performed best at 80% soil moisture, the invasive species grew more rapidly, showed higher net photosynthetic rates in all circumstances and showed less evidence of stress. Variations in soil moisture levels promoted a stronger response in the native species, reducing biomass accumulation and triggering a stronger biochemical response than in the invasive species.

scholarly journals Emerging fungal pathogen of an invasive grass: Implications for competition with native plant species

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory
Keyword(s):  
Invasive Species ◽  
Plant Species ◽  
Fungal Pathogen ◽  
Native Species ◽  
Grass Species ◽  
Leaf Spot Disease ◽  
Native Plant ◽  
Invasive Grass ◽  
Native Plant Species ◽  
Species Specific

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.

Measurement of the influence of low water availability on the productivity of Agave weberi cultivated under controlled irrigation

2014 ◽  
Vol 94 (2) ◽  
pp. 439-444 ◽  
Author(s):  
Steven J. Bergsten ◽  
J. Ryan Stewart
Keyword(s):  
Soil Moisture ◽  
Nutrient Uptake ◽  
Water Availability ◽  
Irrigation System ◽  
Biomass Accumulation ◽  
Dry Weight ◽  
Energy Crop ◽  
Soil Conditions ◽  
Controlled Irrigation ◽  
Dry Soil

Bergsten, S. J. and Stewart, J. R. 2014. Measurement of the influence of low water availability on the productivity of Agave weberi cultivated under controlled irrigation. Can. J. Plant Sci. 94: 439–444. In recent years, research has focused on determining the potential of Agave to be utilized for bioenergy production due to its ability to grow in arid and marginal lands. However, little is known regarding its productivity under limited water conditions. Most Agave species can tolerate low soil-moisture levels, but it is unclear at what point productivity will be significantly constrained. Using an automated irrigation system under greenhouse conditions, we evaluated the effects of low to high volumetric water content (VWC) levels on biomass accumulation and nutrient uptake of a putative bioenergy crop, Agave weberi. Plants were exposed to four constant VWC levels (0.05, 0.12, 0.19, and 0.26 m3 m−3). Shoot dry weight of plants in the 0.26 m3 m−3 treatment was significantly higher than those in the 0.05 m3 m−3 treatment, but not than those in the intermediate treatments. Both chlorophyll count and nutrient uptake decreased as VWC level decreased. Although plants were fairly productive under moderately dry soil conditions, it would be expected that over time, plants receiving high levels of irrigation would have greater growth than plants in dry soil moisture levels. However, similar yields between the well-watered and moderately dry treatments suggest that A. weberi should be further evaluated as a candidate energy crop in more long-term field trials.

Above- and below-ground responses of native and invasive prairie grasses to future climate scenarios

Botany ◽  
2016 ◽  
Vol 94 (6) ◽  
pp. 471-479 ◽  
Author(s):  
Eric B. Duell ◽  
Gail W.T. Wilson ◽  
Karen R. Hickman
Keyword(s):  
Climate Change ◽  
Water Availability ◽  
Native Species ◽  
Soil Microbial Communities ◽  
Am Fungi ◽  
Grass Species ◽  
Climate Change Scenarios ◽  
Bothriochloa Ischaemum ◽  
Invasive Grasses ◽  
Below Ground

More intense and frequent droughts, coupled with elevated temperatures, are projected for grasslands worldwide. Although it has been suggested that alterations in temperature and precipitation will increase the success of biological invasions, studies that combine these climate change scenarios are limited. These changes in climate may increase the success of non-native, invasive plant species directly, as these species often possess traits that are favored by variable climates, or indirectly through negative impacts on native vegetation or alterations in soil microbial communities, such as arbuscular mycorrhizal (AM) fungi. The goal of our research was to assess above- and below-ground production and mycorrhizal fungal abundance of functionally similar native and invasive non-native grass species under projected climate-change scenarios. We assessed plant biomass, intra-radical AM root colonization, and relative abundance of extra-radical fungal biomass of two native (Schizachyrium scoparium (Michx.) Nash, Pascopyrum smithii (Rydb.) Á.Löve) and two invasive (Bothriochloa ischaemum (L.) Keng, Bromus inermis Leyss.) grass species subjected to increased temperature and decreased soil water availability. Regardless of temperature or soil moisture, the invasive grasses in our study displayed greater seedling growth as compared with paired native species. Invasive grasses were also generally characterized by greater intra-radical colonization by AM fungi, compared with native species. Our data suggest that invasive grasses will continue to be problematic and successfully out-compete native grasses following increased temperatures and reduced water availability, as projected by climate-change models.

High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Ecological Impact ◽  
Marine Species ◽  
Ecological Impacts ◽  
Negative Effects ◽  
Marine Predator ◽  
Eastern Gulf Of Mexico ◽  
Red Grouper ◽  
Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

scholarly journals Soil Moisture Dynamics in Response to Precipitation and Thinning in a Semi-Dry Forest in Northern Mexico

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 105
Author(s):  
Argelia E. Rascón-Ramos ◽  
Martín Martínez-Salvador ◽  
Gabriel Sosa-Pérez ◽  
Federico Villarreal-Guerrero ◽  
Alfredo Pinedo-Alvarez ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Management ◽  
Water Availability ◽  
Dry Forest ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Northern Mexico ◽  
The Difference ◽  
The Impact ◽  
Moisture Dynamics

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

scholarly journals Diet composition of the invasive red-whiskered bulbul Pycnonotus jocosus in Mauritius

2010 ◽  
Vol 26 (3) ◽  
pp. 347-350 ◽  
Author(s):  
Jannie Fries Linnebjerg ◽  
Dennis M. Hansen ◽  
Nancy Bunbury ◽  
Jens M. Olesen
Keyword(s):  
Invasive Species ◽  
Introduced Species ◽  
Native Species ◽  
Diet Composition ◽  
Ecological Perspective ◽  
Positive Interactions ◽  
Invasional Meltdown ◽  
Ecological Processes ◽  
Successful Establishment ◽  
The Impact

Disruption of ecosystems is one of the biggest threats posed by invasive species (Mack et al. 2000). Thus, one of the most important challenges is to understand the impact of exotic species on native species and habitats (e.g. Jones 2008). The probability that entire ‘invasive communities’ will develop increases as more species establish in new areas (Bourgeois et al. 2005). For example, introduced species may act in concert, facilitating one another's invasion, and increasing the likelihood of successful establishment, spread and impact. Simberloff & Von Holle (1999) introduced the term ‘invasional meltdown’ for this process, which has received widespread attention since (e.g. O'Dowd 2003, Richardson et al. 2000, Simberloff 2006). Positive interactions among introduced species are relatively common, but few have been studied in detail (Traveset & Richardson 2006). Examples include introduced insects and birds that pollinate and disperse exotic plants, thereby facilitating the spread of these species into non-invaded habitats (Goulson 2003, Mandon-Dalger et al. 2004, Simberloff & Von Holle 1999). From a more general ecological perspective, the study of interactions involving introduced and invasive species can contribute to our knowledge of ecological processes – for example, community assembly and indirect interactions.

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