scholarly journals Removal of invasive Scotch broom increases its negative effects on soil and plant communities

Author(s):  
Robert Slesak ◽  
Timothy Harrington ◽  
Anthony D'Amato ◽  
David Peter

Abstract Scotch broom is an aggressive invasive species of major concern in coast Douglas-fir forests of the Pacific Northwest USA. Control efforts are common, but potential for ecosystem recovery following Scotch broom removal is unclear. We assessed the potential for ecosystem recovery following broom removal at two sites that contrasted strongly in soil quality (i.e., texture and nutrient pool size) in western Washington and Oregon. Comparisons were made among replicated plots where Scotch broom was never present (uninvaded), retained, or removed. Microclimate (photosynthetically active radiation (PAR), soil temperature and moisture), soil properties, and vegetation were monitored during 2013 to 2017. Scotch broom removal increased PAR and soil temperature at both sites but had limited effects on soil moisture. Concentrations of Ca, Mg, K, and P were significantly lower with Scotch broom removal compared to the uninvaded and retained treatments, with the effect being most pronounced at the low-quality site. NMS ordinations indicated that the treatments differed in vegetation composition, with limited evidence for recovery in the removal treatment. Nonnative and native species varied inversely in their abundance responses, where nonnative species abundance was greatest in the removal treatment, intermediate in the retained treatment, and lowest in the uninvaded treatment, indicating occurrence of a secondary invasion following removal. As with the soil response, effects were more pronounced at the low-quality site. Our findings indicate that Scotch broom removal exacerbates negative effects on soil and plant communities, with little evidence of ecosystem recovery over our study period. These findings highlight the importance of controlling Scotch broom invasions immediately after the species establishes, especially at low-quality sites that are more susceptible to Scotch broom invasion and negative legacy effects.

2019 ◽  
Author(s):  
Joseph E Braasch ◽  
Maria A Johnson ◽  
Susan P Harrison ◽  
Katrina M Dlugosch

AbstractIntroduced species are a common feature of modern plant communities and experience environmental challenges alongside native species. Changes to the environment may reveal distinct species-environment relationships for native and introduced components of plant communities. Extreme environmental change, such as drought, is predicted to result in declines in native species and increased opportunities for invasion, but empirical support for these ideas remains mixed. We tested for differences in the response of native and invaded species to environmental changes by analyzing a longterm dataset of species abundance in California grasslands collected during a period of severe drought. Sampling sites included a combination of stressful serpentine soils, which are resilient against invasion and maintain diverse native species assemblages, and more benign nonserpentine soils, which are heavily invaded and harbor low levels of native species cover. We found a significant correlation between sampling year and species composition for nonserpentine sites, but not for serpentine sites. These patterns were repeated when only introduced species were included in the analysis but no pattern of change was found for native species. The species most strongly associated with directional change on nonserpentine soils were three invasive Eurasian grasses, Bromus hordaceus, Taeniatherium caput-medusae, and Avena fatua. Differences in species composition on both serpentine and nonserpentine soils were significantly correlated with specific leaf area, a trait which has been linked to drought tolerance in these communities, although changes in abundance for the three Eurasian grasses most strongly associated with change did not consistently follow this pattern. Our analyses indicate relatively stable native community composition and strong directional change in introduced species composition, contradicting predictions for how native and introduced species will respond to environmental shifts, but supporting the hypothesis that native and invading species groups have important functional differences that shape their relationships to the environment.


Oecologia ◽  
2022 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato ◽  
David H. Peter

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac

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.


Author(s):  
M. I. Dzhalalova ◽  
A. B. Biarslanov ◽  
D. B. Asgerova

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexia Stokes ◽  
Guillermo Angeles ◽  
Fabien Anthelme ◽  
Eduardo Aranda-Delgado ◽  
Isabelle Barois ◽  
...  

Abstract Objectives Altitude integrates changes in environmental conditions that determine shifts in vegetation, including temperature, precipitation, solar radiation and edaphogenetic processes. In turn, vegetation alters soil biophysical properties through litter input, root growth, microbial and macrofaunal interactions. The belowground traits of plant communities modify soil processes in different ways, but it is not known how root traits influence soil biota at the community level. We collected data to investigate how elevation affects belowground community traits and soil microbial and faunal communities. This dataset comprises data from a temperate climate in France and a twin study was performed in a tropical zone in Mexico. Data description The paper describes soil physical and chemical properties, climatic variables, plant community composition and species abundance, plant community traits, soil microbial functional diversity and macrofaunal abundance and diversity. Data are provided for six elevations (1400–2400 m) ranging from montane forest to alpine prairie. We focused on soil biophysical properties beneath three dominant plant species that structure local vegetation. These data are useful for understanding how shifts in vegetation communities affect belowground processes, such as water infiltration, soil aggregation and carbon storage. Data will also help researchers understand how plant communities adjust to a changing climate/environment.


2001 ◽  
Vol 79 (4) ◽  
pp. 510-519 ◽  
Author(s):  
Philippe Lebreton ◽  
Bernard Jeangros ◽  
Christiane Gallet ◽  
Jan Scehovic

Organic and mineral components have been analysed on 18 dicotyledonous species of permanent grassland communities. Multivariate analysis revealed an opposition between a macromolecular pool (cellulose and lignin) and a nutrient pool (potassium and phosphorus, nitrogen). The first pole is characterized by Tragopogon pratensis L. (Compositae) and Galium mollugo L. (Rubiaceae), the second by Anthriscus sylvestris (L.) Hoffm. (Umbelliferae) and Geranium sylvaticum L. (Geraniaceae). The most thermo-helio-xerophilous species (Knautia arvensis (L.) Coult and Tragopogon pratensis) belong to the first group, whereas the second group includes the cool-environment species (like Alchemilla xanthochlora Roth.), which reveals an ecophysiological determinism. Moreover, correlations between the biochemical and ecological structure, and other interrelated parameters, including sclerophylly, have been shown. Compared to lignous and sempervirent plant communities, the grassland species have lower phenolic and lignin contents but higher glucide and nutrient (potassium and phosphorus) contents, which is in accordance with their food value. For this herbaceous community, the C/N ratio indicates the same general equilibrium between cell-wall macromolecules and nitrogen than for two other plant communities (mainly ligneous) previously studied, with some differences revealing distinct trends from the same general metabolic sheme.Key words: dicotyledonous plant communities, biochemical organization, C/N ratio, ecophysiology.


2015 ◽  
Vol 398 (1-2) ◽  
pp. 281-289 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato

Koedoe ◽  
1997 ◽  
Vol 40 (2) ◽  
Author(s):  
C.M. Smit ◽  
G.J. Bredenkamp ◽  
N. Van Rooyen ◽  
A.E. Van Wyk ◽  
J.M. Combrinck

A vegetation survey of the Witbank Nature Reserve, comprising 847 hectares, was conducted. Phytosociological data were used to identify plant communities, as well as to determine alpha and beta diversities. Eleven plant communities were recognised, two of these are subdivided into sub- communities, resulting in 14 vegetation units. These communities represent four main vegetation types, namely grassland, woodland, wetland and disturbed vegetation. Grassland communities have the highest plant diversity and wetland vegetation the lowest. Floristic composition indicates that the vegetation of the Rocky Highveld Grassland has affinities to the grassland and savanna biomes and also to the Afromontane vegetation of the Great Escarpment. An ordination scatter diagram shows the distribution of the 14 plant communities or sub-communities along a soil moisture gradient, as well as along a soil depth/surface rock gradient. The sequence of communities along the soil moisture gradient is used for calculating beta-diversity indices. It is concluded that the relatively small size of the Witbank Nature Reserve is unlikely to have significant negative effects on the phytodiversity of the various plant communities. This nature reserve is therefore of considerable importance in conserving a representative sample of the Rocky Highveld Grassland.


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