scholarly journals Hiking and Livestock Favor Non-Native Plants in The High Andes

Author(s):  
María Alisa Alvarez ◽  
Ana Agustina Barros ◽  
Diego Pedro Vázquez ◽  
Lorena de Jesús Bonjour ◽  
Jonas Lembrechts ◽  
...  

Abstract Hikers and livestock using mountain trails damage native vegetation and act as seed vectors, thus favouring the spread of non-native plants. We evaluated the effect of trails and livestock abundance on the success of non-native plants in the arid central Andes of Argentina. We surveyed six trails, covering elevations between 2400 m and 3570 m a.s.l. and recorded non-native and native vegetation using transects distributed along the elevational gradient and spanning distances up to 22 m from the trail. We assessed how non-native occurrence, richness and cover varied with distance from the trail, intensity of use by livestock, native plant community composition and elevation. We found that trails favoured non-native occurrence, but did not influence richness and cover, while livestock favoured non-native occurrence, richness and cover. Non-native richness and cover decreased with elevation and varied with native community composition. In addition, non-native richness was positively correlated with native shrub cover suggesting possible facilitative interactions. Our results show that despite strong environmental filtering that decreases non-native abundance with elevation, non-natives occur up to the upper limits of vegetation, and that trails and livestock favour their spread in the mountains.

Botany ◽  
2017 ◽  
Vol 95 (5) ◽  
pp. 513-520 ◽  
Author(s):  
Brittany A. North ◽  
Albert P. Torzilli

The potential role of fungal root endophytes (including mycorrhizae) in the invasiveness of Microstegium vimineum (Trin.) A. Camus, was researched using automated ribosomal intergenic spacer analysis (ARISA) and brightfield microscopy. Fungal communities of roots from two native plants (Onoclea sensibilis L. and Amphicarpaea bracteata (L.) Fernald) were compared with those found in Microstegium. Fungal communities from the bulk soils also were examined in terms of their potential influence on the root mycobiomes. All three plants occurred in natural communities as monocultures and together in one mixed community in Northern Virginia where Microstegium has recently invaded. Principal coordinate analysis of ARISA data identified fungal communities unique to roots from each monoculture. When the three plants co-occurred in a mixed setting, Microstegium was found to maintain its distinct fungal community while the fungal communities of the two native plants overlapped. In contrast, soil fungal communities showed no specific plant associations. Brightfield microscopy confirmed the presence of endophytic fungi in all three plants. The results recorded here suggest a positive contribution by the root mycobiome in promoting the invasive ability of Microstegium, providing a basis for future experiments testing this hypothesis.


2018 ◽  
Vol 11 (4) ◽  
pp. 175-180 ◽  
Author(s):  
Christopher L. Zimmerman ◽  
Rebecca R. Shirer ◽  
Jeffrey D. Corbin

AbstractProjects that aim to control invasive species often assume that a reduction of the target species will increase native species abundance. However, reports of the responses of native species following exotic species control are relatively rare. We assessed the recovery of the native community in five tidal wetland locations in which we attempted to eradicate the invasive common reed [Phragmites australis (Cav.) Trin. ex Steud.]. We tested whether 3 yr of treatment were able to eradicate Phragmites and promote recovery of the native plant community. After 3 yr of treatment, Phragmites density declined sharply in all treated stands, though it was not eradicated in any of them. Native plant cover increased significantly in treated areas, and community composition, particularly in smaller stands, converged toward that of uninvaded habitat. Thus, even within the relatively short timescale of the treatments and monitoring, significant progress was made toward achieving the goals of controlling Phragmites infestations and promoting native biodiversity. There was a trend toward greater promise for success in smaller stands than larger stands, as has been observed in other studies. A greater emphasis on monitoring whole-community responses to exotic plant control, across a range of conditions, would enhance our ability to plan and design successful management strategies.


Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 426 ◽  
Author(s):  
David J. Gibson ◽  
Lindsay A. Shupert ◽  
Xian Liu

Control of invasive exotic species in restorations without compromising the native plant community is a challenge. Efficacy of exotic species control needs to consider collateral effects on the associated plant community. We asked (1) if short-term control of a dominant exotic invasive, Lespedeza cuneata in grassland restorations allows establishment of a more diverse native plant community, and (2) if control of the exotic and supplemental seed addition allows establishment of native species. A manipulative experiment tested the effects of herbicide treatments (five triclopyr and fluroxypyr formulations plus an untreated control) and seed addition (and unseeded control) on taxonomic and phylogenetic diversity, and community composition of restored grasslands in three sites over three years. We assessed response of L. cuneata through stem density counts, and response of the plant community through estimates of canopy cover. Herbicide treatments reduced the abundance of the exotic in the first field season leading to a less dispersed community composition compared with untreated controls, with the exotic regaining dominance by the third year. Supplemental seed addition did not provide extra resistance of the native community to reinvasion of the exotic. The communities were phylogenetically over-dispersed, but there was a short-term shift to lower phylogenetic diversity in response to herbicides consistent with a decrease in biotic filtering. Native plant communities in these grassland restorations were resilient to short-term reduction in abundance of a dominant invasive even though it was insufficient to provide an establishment window for native species establishment.


2021 ◽  
pp. 1-28
Author(s):  
Inés Ibáñez ◽  
Gang Liu ◽  
Laís Petri ◽  
Sam Schaffer-Morrison ◽  
Sheila Schueller

Abstract Risk assessments of biological invasions rarely account for native species performance and community features, but this assessment could provide additional insights for management aimed at decreasing vulnerability or increasing resistance of a plant community to invasions. To gather information on the drivers of native plant communities’ vulnerability and resistance to invasion, we conducted a literature search and meta-analysis. From the data collected we compared native and invasive plant performance between sites with high and low levels of invasion. We then investigated under which conditions native performance increased, decreased, or did not change with respect to invasive plants. We analyzed data from 214 publications summing to 506 observations. There were six main drivers of vulnerability to invasion: disturbance, decrease in resources, increase in resources, lack of biotic resistance, lack of natural enemies, and differences in propagule availability between native and invasive species. The two mechanisms of vulnerability to invasion associated with a strong decline in native plant performance were propagule availability and lack of biotic resistance. Native plants marginally benefited from enemy release and from decreases in resources, while invasive plants strongly benefited from both increased resources and lack of enemies. Fluctuation of resources, decreases and increases, were strongly associated with higher invasive performance while native plants varied in their response. These differences were particularly strong in instances of decreasing water or nutrients, and of increasing light and nutrients. We found overall neutral to positive responses of native plant communities to disturbance; but natives were outperformed by invasive species when disturbance was caused by human activities. We identified ecosystem features associated with both vulnerability and resistance to invasion, then used our results to inform management aimed at protecting the native community.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reham F. El-Barougy ◽  
Ibrahim A. Elgamal ◽  
Abdel-Hamid A. Khedr ◽  
Louis-Félix Bersier

AbstractAlien impact on native diversity could be a function of both the relatedness of alien species to native community and resources availability. Here, we investigated whether alien plants expand or decrease the functional and phylogenetic space of native plant communities, and how this is affected by alien relatedness to natives and by resources availability. We used a trait-environment dataset of 33 alien and 130 native plants in 83 pairs of invaded and non-invaded plots, covering a gradient of soil resources (organic matter-nitrogen) in Saint-Katherine-Protectorate, Egypt. First, we compared the changes in native composition and calculated alien relatedness to natives within each pair of plots. Second, we tested the effects of resources availability and relatedness on the magnitude of alien impact (defined as a change in native diversity). We found that native composition was phylogenetically less but functionally more diverse in invaded plots compared to non-invaded ones. Moreover, in resources-rich plots, dissimilar aliens to natives significantly increased native diversity, while in resource-limited ones, similar aliens to natives declined native diversity. These results suggest that the assessment of alien impacts in arid-regions is significantly linked to resources-availability and relatedness to natives. Hence, future studies should test the generality of our findings in different environments.


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