Loss of Microbiome Ecological Niches and Diversity by Global Change and Trophic Downgrading

Saleem, Muhammad

doi:10.1007/978-3-319-11665-5_4

Cited by 7 publications

(5 citation statements)

References 120 publications

(86 reference statements)

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“…Until recently, the role played by macroorganisms in the control of microbial diversity has been largely ignored in the literature ( Mihaljevic, 2012 ; Saleem, 2015 ; Li et al, 2016 ); the interactions between hosts and their microbiota being mostly considered in the light of the potential effect, beneficial or deleterious, for the macroorganism’s life ( Harris, 1993 ; Mao-Jones et al, 2010 ; Nayak, 2010b ; Clements et al, 2014 ). Such a one-sided and asymmetric view of macroorganism–microbe interactions is exemplified by studies on fish and their intestinal microbial communities which generally focus on the benefits for the fish ( Nayak, 2010a , b ; Clements et al, 2014 ) or in a more limited way, how the fish gut microbiota support hosts’ functional roles ( Smriga et al, 2010 ; Mouchet et al, 2012 ).…”

Section: Review Of the Main Processes Regulating Marine Microbial DIVmentioning

confidence: 99%

“…In such scenario, the observed biodiversity erosion of macroorganisms in marine ecosystems (i.e., defaunation; Estes et al, 2011 ; Mora et al, 2011 ; McCauley et al, 2015 ) may ultimately impact on the spatio-temporal dynamics of microbial metacommunities and the ecosystem processes they sustain. These considerations need further attention notably as it was recently stated that “ nothing is known about how the aquatic ecosystem trophic downgrading is linked to the microbiome diversity loss and associated ecosystem services ” ( Saleem, 2015 ).…”

Section: Sustaining the Rarementioning

confidence: 99%

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Sustaining Rare Marine Microorganisms: Macroorganisms As Repositories and Dispersal Agents of Microbial Diversity

et al. 2017

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Recent analyses revealed that most of the biodiversity observed in marine microbial communities is represented by organisms with low abundance but, nonetheless essential for ecosystem dynamics and processes across both temporal and spatial scales. Surprisingly, few studies have considered the effect of macroorganism–microbe interactions on the ecology and distribution dynamics of rare microbial taxa. In this review, we synthesize several lines of evidence that these relationships cannot be neglected any longer. First, we provide empirical support that the microbiota of macroorganisms represents a significant part of marine bacterial biodiversity and that host-microbe interactions benefit to certain microbial populations which are part of the rare biosphere (i.e., opportunistic copiotrophic organisms). Second, we reveal the major role that macroorganisms may have on the dispersal and the geographic distribution of microbes. Third, we introduce an innovative and integrated view of the interactions between microbes and macroorganisms, namely sustaining the rares, which suggests that macroorganisms favor the maintenance of marine microbial diversity and are involved in the regulation of its richness and dynamics. Finally, we show how this hypothesis complements existing theories in microbial ecology and offers new perspectives about the importance of macroorganisms for the microbial biosphere, particularly the rare members.

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Section: Review Of the Main Processes Regulating Marine Microbial DIVmentioning

confidence: 99%

Section: Sustaining the Rarementioning

confidence: 99%

Sustaining Rare Marine Microorganisms: Macroorganisms As Repositories and Dispersal Agents of Microbial Diversity

et al. 2017

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“…The presence of extremely long transients close to bifurcations (as shown in this article) opens the possibility that some ecosystems may be currently living in a ghost state, transitioning towards a less complex state [76,77,101] due to impact of human activity including deforestation, environmental contamination or defaunation. Anthropogenic impacts are making ecosystems to experience defaunation [102,103], suffering extinction cascades due to trophic downgrading or ecological meltdown caused by ecosystem domestication (i.e.…”

Section: Discussionmentioning

confidence: 75%

Habitat loss causes long extinction transients in small trophic chains

et al. 2021

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Transients in ecology are extremely important since they determine how equilibria are approached. The debate on the dynamic stability of ecosystems has been largely focused on equilibrium states. However, since ecosystems are constantly changing due to climate conditions or to perturbations such as the climate crisis or anthropogenic actions (habitat destruction, deforestation, or defaunation), it is important to study how dynamics can proceed till equilibria. In this contribution we investigate dynamics and transient phenomena in small food chains using mathematical models. We are interested in the impact of habitat loss in ecosystems with vegetation undergoing facilitation. We provide a thorough dynamical study of a small food chain system given by three trophic levels: vegetation, herbivores, and predators. The dynamics of the vegetation alone suffers a saddle-node bifurcation, causing extremely long transients. The addition of a herbivore introduces a remarkable number of new phenomena. Specifically, we show that, apart from the saddle node involving the extinction of the full system, a transcritical and a supercritical Hopf-Andronov bifurcation allow for the coexistence of vegetation and herbivores via non-oscillatory and oscillatory dynamics, respectively. Furthermore, a global transition given by a heteroclinic bifurcation is also shown to cause a full extinction. The addition of a predator species to the previous systems introduces further complexity and dynamics, also allowing for the coupling of different transient phenomena such as ghost transients and transient oscillations after the heteroclinic bifurcation. Our study shows how the increase of ecological complexity via addition of new trophic levels and their associated nonlinear interactions may modify dynamics, bifurcations, and transient phenomena.

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“…On the other hand, facilitative interactions are key for survival of the less adapted plants even in extreme environments (Berdugo et al 2018), which makes plant-plant interaction networks nested on key species whose loss may produce cascading extinctions (Thébault et al 2007;Dunne & Williams 2009;Rocha et al 2018). These cascading effects can even act through trophic levels, involving groups other than plants (Jones et al 1996;Wright et al 2004;Cuddington et al 2011) and even affect microbial diversity (Saleem 2015). Thus it is important to understand species-species interactions in these communities, especially their strength and hierarchy, and studies aimed at understanding community interactions through networks in extreme environments are still insufficient and usually not assessing physiological limits of plants (something key in these very high aridity levels).…”

Section: B Biodiversity Feedbacksmentioning

confidence: 99%

Ecological mechanisms underlying aridity thresholds in global drylands

Berdugo¹,

Vidiella²,

Solé³

et al. 2021

Preprint

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With ongoing climate change, the probability of crossing environmental thresholds promoting abrupt changes in ecosystem structure and functioning is higher than ever. In drylands (sites where it rains less than 60% of what is evaporated), recent research has shown how the crossing of three particular aridity thresholds (defining three consecutive phases, namely vegetation decline, soil disruption and systemic breakdown) leads to abrupt changes on ecosystem structural and functional attributes. Despite the importance of these findings and their implications to develop effective monitoring and adaptation actions to combat climate change, we lack a proper understanding of the mechanisms unleashing these abrupt shifts.Here we revise and discuss multiple mechanisms that may explain the existence of aridity thresholds observed across global drylands, and discuss the potential amplification mechanisms that may underpin hypothetical abrupt temporal shifts with climate change. We found that each aridity threshold is likely involving specific processes. In the vegetation decline phase we review mainly physiological mechanisms of plant adaptation to water shortages as main cause of this threshold. In the second threshold we identified three pathways involving mechanisms that propagates changes from plants to soil leading to a soil disruption: erosive mechanisms, mechanisms linked to an aridity-induced shrub encroachment and mechanisms linked to nutrient cycling and circulation. Finally, in the systemic breakdown phase we reviewed plant-plant amplification mechanisms triggered by survival limits of plants that may cause sudden diversity losses and plant-atmospheric feedbacks that may link vegetation collapse with further and critical aridification. By identifying, revising and linking relevant mechanisms to each aridity threshold, we catalogued a set of specific hypotheses and recommendations based on identified knowledge gaps concerning the study of mechanisms of threshold emergence in drylands. Moreover, we were able to establish plausible factors that are context dependent and may influence the occurrence of abrupt changes in time and we created a mechanistic-based conceptual model on how abrupt changes may emerge as aridity increases. This has importance for focusing future research efforts on aridity thresholds and for developing strategies to track, adapt to or even revert these abrupt ecosystem changes in the future.

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Loss of Microbiome Ecological Niches and Diversity by Global Change and Trophic Downgrading

Abstract: Global change that include, but is not limited to these: habitat loss and disturbance, greenhouse gas emissions, rising climate warming and CO 2 ,

Cited by 7 publications

References 120 publications

Sustaining Rare Marine Microorganisms: Macroorganisms As Repositories and Dispersal Agents of Microbial Diversity

Sustaining Rare Marine Microorganisms: Macroorganisms As Repositories and Dispersal Agents of Microbial Diversity

Habitat loss causes long extinction transients in small trophic chains

Ecological mechanisms underlying aridity thresholds in global drylands

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