Species in variable environments

2019 ◽  
pp. 287-306
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Environmental Change ◽  
Species Interactions ◽  
Species Coexistence ◽  
Dynamic State ◽  
Ecological Communities ◽  
Variable Environments ◽  
Degraded Ecosystems ◽  
Alternative Community ◽  
Response To Environmental Change ◽  
Alternative Community States

Species and communities may exist in a dynamic state of change in response to environmental variation and disturbance. This chapter explores the consequences of variable environments and disturbance to species interactions and community structure. In particular, it examines how disturbance can result in the succession of ecological communities, how disturbance may promote (or hinder) species coexistence, how a varying environment can promote species coexistence through a mechanism called the “storage effect”, and how communities may shift between alternative states in response to environmental change. The latter topic is particularly relevant to the management of biotic resources and the restoration of degraded ecosystems, as systems may respond to environmental change abruptly at a “tipping point”, leading to alternative community states that can be difficult to reverse.

scholarly journals Vulnerable species interactions are important for the stability of mutualistic networks

2019 ◽  
Author(s):  
Benno I. Simmons ◽  
Hannah S. Wauchope ◽  
Tatsuya Amano ◽  
Lynn V. Dicks ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Species Interaction ◽  
Interaction Networks ◽  
Ecological Communities ◽  
Ecological Context ◽  
Intrinsic Properties ◽  
Network Stability ◽  
Starting Point ◽  
The Stability

AbstractSpecies are central to ecology and conservation. However, it is the interactions between species that generate the functions on which ecosystems and humans depend. Despite the importance of interactions, we lack an understanding of the risk that their loss poses to ecological communities. Here, we quantify risk as a function of the vulnerability (likelihood of loss) and importance (contribution to network stability in terms of species coexistence) of 4330 mutualistic interactions from 41 empirical pollination and seed dispersal networks across six continents. Remarkably, we find that more vulnerable interactions are also more important: the interactions that contribute most to network stability are those that are most likely to be lost. Furthermore, most interactions tend to have more similar vulnerability and importance across networks than expected by chance, suggesting that vulnerability and importance may be intrinsic properties of interactions, rather than only a function of ecological context. These results provide a starting point for prioritising interactions for conservation in species interaction networks and, in areas lacking network data, could allow interaction properties to be inferred from taxonomy alone.

scholarly journals Evolutionary rescue can maintain an oscillating community undergoing environmental change

2013 ◽  
Vol 3 (6) ◽  
pp. 20130036 ◽  
Author(s):  
Gregor F. Fussmann ◽  
Andrew Gonzalez
Keyword(s):  
Environmental Change ◽  
Community Dynamics ◽  
Ecological Communities ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Before And After ◽  
Internal Forces ◽  
Frequency Changes ◽  
Response To Environmental Change ◽  
Physiological Acclimation

The persistence of ecological communities is challenged by widespread and rapid environmental change. In many cases, persistence may not be assured via physiological acclimation or migration and so species must adapt rapidly in situ . This process of evolutionary rescue (ER) occurs when genetic adaptation allows a population to recover from decline initiated by environmental change that would otherwise cause extirpation. Community evolutionary rescue (CER) occurs when one or more species undergo a rapid evolutionary response to environmental change, resulting in the recovery of the ancestral community. Here, we study the dynamics of CER within a three-species community coexisting by virtue of resource oscillations brought about by nonlinear interactions between two species competing for a live resource. We allowed gradual environmental change to affect the traits that determine the strength and symmetry of the interaction among species. By allowing the component species to evolve rapidly, we found that: (i) trait evolution can allow CER and ensure the community persists by preventing competitive exclusion during environmental change, (ii) CER brings about a change in the character of the oscillations (period, amplitude) governing coexistence before and after environmental change, and (iii) CER may depend on evolutionary change that occurs simultaneously with or subsequently to environmental change. We were able to show that a change in the character of community oscillations may be a signature that a community is undergoing ER. Our study extends the theory on ER to a world of nonlinear community dynamics where—despite high-frequency changes of population abundances—adaptive evolutionary trait change can be gradual and directional, and therefore contribute to community rescue. ER may happen in real, complex communities that fluctuate owing to a mix of external and internal forces. Experiments testing this theory are now required to validate our predictions.

scholarly journals Higher order interactions and species coexistence

2020 ◽  
Author(s):  
Pragya Singh ◽  
Gaurav Baruah
Keyword(s):  
Intraspecific Competition ◽  
Species Interactions ◽  
Species Coexistence ◽  
General Rule ◽  
Higher Order ◽  
Volterra Model ◽  
Ecological Communities ◽  
Wide Range ◽  
Analytical Result ◽  
Underlying Mechanisms

AbstractHigher order interactions (HOIs) have been suggested to stabilize diverse ecological communities. However, their role in maintaining species coexistence from the perspective of modern coexistence theory is not known. Here, using generalized Lotka-Volterra model, we derive a general rule for species coexistence modulated by HOIs. We show that where pairwise species interactions fail to promote species coexistence in regions of extreme fitness differences, negative HOIs that intensify pairwise competition, however, can promote coexistence provided that HOIs strengthen intraspecific competition more than interspecific competition. In contrast, positive HOIs that alleviate pairwise competition can stabilize coexistence across a wide range of fitness differences, irrespective of differences in strength of inter- and intraspecific competition. In addition, we extend our three-species analytical result to multispecies communities and show, using simulations, that multispecies coexistence is possible provided that strength of negative intraspecific HOIs is higher than interspecific HOIs. Our work sheds light on the underlying mechanisms through which HOIs can maintain species diversity.

USING HISTORICAL ANNUAL REPORTS IN TEACHING: LETTING THE PAST BENEFIT THE PRESENT

1992 ◽  
Vol 19 (1) ◽  
pp. 29-50 ◽  
Author(s):  
Joel Amernic ◽  
Ramy Elitzur
Keyword(s):  
Environmental Change ◽  
Cash Flow ◽  
Accounting Education ◽  
Annual Reports ◽  
The Past ◽  
Response To Environmental Change

In this article, it is suggested that accounting education may be enhanced by the use of published historical accounting materials, such as annual reports. Comparing such materials with modern reports serves to reinforce the notion that accounting evolves in response to environmental change. Further, requiring students to analytically derive cash flow statements from historical published annual reports provides several direct pedagogical benefits.

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