The effects of soil-plant feedback among native and invasive species
Plants alters soil physical and chemical properties as well to microbial communities; the soil response to plants’ effect is called feedback. Plant-soil feedback can be negative, neutral or positive depending on the growth effect of the soil modified by the plant compared to unmodified soil (Kulmatiski, 2008). Factors regulating plant-soil feedback, which varies from positive to negative among plant species remain uncertain. Plant-soil feedback (PSF) is a relatively new topic; there is not enough information about the association of plants with microbial communities. Studies have focused on factors that determine which non-native species are more likely to succeed while others fail. Plant-soil feedback can play a lead role in competition between potential invaders and the native community (Kulmatiski, 2008). A better understanding of the interactions of PSF and invasive species will improve the management techniques of invasive species. Plant-soil feedback suggests mechanisms for plant diversity succession and invasion. The purpose of the following review is to discuss how plant-soil feedback allows the success of invasive plant and how the invaders interact with native.
How are invasive and native species interacting?
Competition
Soil microbes and pathogens may not have the same response to native plants and invasive plants. Invasive plants can experience positive plant-soil feedback in their new “habitat” while a negative feedback in their native range (Day, 2015). Invasive plants respond better to soil in their new habitat than in the native habitat. However, the soil community positive response may not guaranty the non-native success as an invasive species (Beest, 2009). For example, the interaction of invasive species with soil pathogens can decline the invasive species population and restrain the growth of successful invaders (Day, 2015). Other studies found no significant plant-soil feedback effect in either live or sterile soil when tested for plant-soil feedback in the presence of plant competition (Crawford, 2017). Other factors such as the competition of native species or an empty niche should also be considered to determinate the successes of the invasive species. Plant-soil feedback can help understand the abundance of invasive plants.
Conspecific
Conspecific species could help understand more about nature and how plant-soil feedback works and differs with invasive species. Positive plant-soil feedback can improve the performance of conspecifics while negative plant-soil feedback can result in soil conditions that decrease the performance of conspecifics and promote the coexistence of other species (Pattison, 2016). Also, positive PSFs are expected to increase plant abundance, persistence and the ability of a plant to invade communities where plants realize negative PSFs (Dostálek, 2016). If plants increase the growth of conspecifics, this process results in a type of positive frequency dependence called positive individual PSF. Positive PSF can result in improved performance of conspecifics, whereas negative PSF can result in soil conditions that decrease the performance of conspecific and promote the coexistence of other species (Kulmatiski et al, 2011). However, other study suggest that invasive species tend to either be unaffected by PSF or create PSFs that increase subsequent conspecific performance (Perkins, 2012).
Community context
The lack of plant-soil feedback in a competitive environment emphasizes the importance of testing how invasive species influence plant-soil interactions in a community context (Scharfy, 2010). It is important to consider community context before analyzing the effects of plant-soil feedback. For example, annuals characteristics, fast growth rates, and poor defense adaptation could make them more susceptible to belowground enemies and more likely to experience negative plant-soil feedback than other functional groups (Kulmatiski, 2008). Also, individual’s traits of soil-conditioning and focal plant species strongly shape the outcome of soil feedbacks (Crawford, 2017). Community context and life history need to be to take into account in future researches. Depending on the particular resources, the habitat requirements and how the new community relationships of recently disturbed soils are found, one plant can affect a second plant (Fitzpatrick, 2017).
What makes invasive species became invasive?
Soil influences how invasive species invade new territories.
Only some non-native species become invasive. Invasive species will invade better in communities that differ from their native habitat (Scharfy, 2010), and the changes in the soil microbial community may result in a “perfect storm” making invasiveness more likely and biological control more difficult (Pattison, 2015). The changes in soil that invasive species made in soil are relevant to stablished in a new habitat. The success and failure of non-native plants could be explained with plant-soil feedback because invasive species realized the least negative PSF while native species present a predominant negative feedback (Kulmatiski et al, 2008). Invasive species often benefit from positive feedback while native species experience negative feedback contributing to an invasive species overall dominance. However, Hilding’s research found an unexpected neutral to positive feedback on native species that may be explained by other factor such as their annual life history. This discrepancy is a clear indicator of further research regarding the kind of plant-soil feedback need to be done.
Concluding remarks:
Plants and soil respond to each other effects. The implication of plant soil feedback in the processes invasion, and this will help to resolve some questions about how non-native become invasive species. Soil have different interactions between non-native and native. Most studies have focused on soil biota and plants, invasive and native plants, interactions while leaving aside other components or factors like plant community and population range. Further research need to focus in differences among different plant groups, and ecosystem.