General comments on the book chapter

Despite it brevity of this week's rough draft, the chapter was interesting and I think targeted about the right level and offered thus far a good mix of theory and empirical examples and wove the two together fairly well. 

I had a few points to add to Alicia's.

1. The chapter gets straight into the vulnerability and resilience approach of CHES. I was wondering if it would be a good idea to build from what Elizabeth King had presented in the discussion on the chapter on CHES where she categorized the various approaches to understanding and unpacking CHES and mentions the V-R approach as one of the approaches based on dynamics as opposed to a disciplinary-based approach. Abrief mention could also be made as to the advantages and limitations of this approach vis-a-vis some othere commonly adopted approaches.

2. Understanding the concepts of V-R from the world of finances may throw up interesting insights into the subject. As a result of external shock, say in the form of a financial meltdown as it happened recently, the discussion in the financial world was how resilient is the financial world to absorb this shock and how quickly can it recover to the pre-shock level. This is supposed to be a function of  a combination of government regulation to build robustness in the financial system and the extent of integration with other financial systems. There could be many more factors. In case of CHESs, may be the second aspect is not possible to be manipulated in which case the first spect is crucial. But the reading of the chapter gives the imporession that resilience or coping capcity is somethng that is intrinsic. Can we not put government regulations to increase resilience in CHES systems? Besides social resilience, there could be cultural resilience aspects as well unless that is a included in the social resilience concept.

As our group has already done some discussion on this topic for the presentation, my comments echo those of my classmates. I would recommend that the chapter start out more general, placing these two emergent properties into a context, and then become more specific, thinking about the ways to model and incorporate these characteristics into research. A few additional thoughts:

1. I found this chapter similar to the prior chapters, and would appreciate some clarification on what makes a characteristic an "emergent property" of the CHES system. Prior to reading this chapter, I would have identified vulnerability and resilience as common properties of ecological systems independently, and social systems independently.  Can we say that any attribute that is a property of each individually, is also a property of the system?  Or in all cases, must it be due to the interaction of the two?  Also, in terms of the similarity of this chapter to previous ones, I would point to Chapter 1.3, in particular sections 3.3 and 3.4.  These sections describe the common dimensions and complexity of HE systems, pointing to the idea of hierarchical couplings, multiple time-spatial scales, the presence of non-linearities, etc.  I would be curious to think about how this complexity influences the common properties that emerge?  For example, non-linearity seems more or less the same to me as the idea of "tipping points" and "thresholds".  Is this all a characteristic and a property?

2.  Thus, perhaps a better starting point would be a good definition of "emergent property" and the criteria used to characterize one.  I understand through reading the chapter, "why vulnerability", but I do not understand "why not" other potentially generalizable emergent properties.  Do all HE systems have to exhibit the characteristic in order for it to be a property?  I like the idea of pointing out that new research is demonstrating new properties of these systems, such as their adaptability.

4.. Overall, I think "smoothing" between the chapters would improve the book.   For example, it maybe that it is it more useful or relevant to understand the mathematics of well-being, but not the mathematics/modeling of vulnerability/resilience.  But, perhaps you should clarify why (and I don't have a good sense of this myself).  And if not, it would be useful to "even out" the mathematics used to describe each (personally, I find it very relevant to know the way vulnerability is modeled, and would agree with Alicia that expanding up this section would be helpful).

5. Fig. 9-5 needs arrows.  Also some elaboration of why an increase in biomass necessarily increases resilience?

Thanks! I look forward to our discussion.

Liz

The concepts of resilience, vulnerability and adaptiveness are obviously central to sustainability. Their roots in the ecology literature are evident from the way they are presented in the chapter. What I personally found lacking is sufficient coverage of what they mean in more socio-political terms, particularly when it comes to understanding how human interactions with the systems they are a part of increase or decrease their resilience.  That is, I would find more normative coverage of how human interventions can and do increase or decrease resilience useful.

For this reason, I found the student group's suggested readings - particularly the Adger et al. 2009 piece - to be a welcome addition. Adger et al. (2009) outline some of the complex sociological and psychological factors that limit any given society's ability to adapt to change. Human societies are highly complex; treating them as rationally responsive to exogenous factors and the tools at their disposal seems somewhat naive.

The Cambridge Group brought up the idea of functional diversity and redundancy as being key to ecosystem resilience. I've attached a 2009 Nature article by Wittebole et al. that treats the biodiversity-functioning theory by examining initial species evenness. This is just the tip of the iceberg in the functional diversity/redundancy literature, but I remember liking this article (probably because it's short and sweet). The abstract is below.

"Owing to the present global biodiversity crisis, the biodiversity–stability relationship and the effect of biodiversity on ecosystem functioning have become major topics in ecology1–3. Biodiversity is a complex term that includes taxonomic, functional, spatial and temporal aspects of organismic diversity, with species richness (the number of species) and evenness (the relative abundance of species) considered among the most important measures4,5. With few exceptions (see, for example, ref. 6), the majority of studies of biodiversity-functioning and biodiversity–stability theory have predominantly examined richness7–11. Here we show, using microbial microcosms, that initial community evenness is a key factor in preserving the functional stability of an ecosystem. Using experimental manipulations of both richness and initial evenness in microcosms with denitrifying bacterial communities, we found that the stability of the net ecosystem denitrification in the face of salinity stress was strongly influenced by the initial evenness of the community. Therefore, when communities are highly uneven, or there is extreme dominance by one or a few species, their functioning is less resistant to environmental stress. Further unravelling how evenness influences ecosystem processes in natural and humanized environments constitutes a major future conceptual challenge."

Continuing on from Jessica's comment....

Is resilience an emergent property of diverse ecosystems?

After the session on Monday (the Cambridge group) questioned whether resilience was an emergent property of human systems (due to high complexity), but not environmental systems. Therefore, was it a misnomer to be asking about emergent properties of CHES when the environment may not have emergent properties? (maybe our discussion wasn’t quite as polar as that).  

This is my response – a brief summary of the ecological literature.

Three things need to be clarified to ask this question properly: 1) Does the type of stress/shock that the ecosystem could be resilient too play a major role in the answer? 2) What is the mechanism of the emergent property? The answer likely being related to functional diversity and redundancy, and 3) It is important to distinguish that much of the ecological literature has been focused on a slightly different (emergent?) property of diverse ecosystems, that of diverse ecosystems having higher biomass productivity.

 A great article on this is Walker et al. [including Ann Kinzig 1999 Plant attribute diversity, resilience, and ecosystem function: the nature and significance of dominant and minor species. Ecosystems 2: 95-113] where they suggest that “many of the minor species [in an ecosystem] are analogues of the dominants [species] in terms of the ecosystem functions they perform, but differ in terms of their capabilities to respond to environmental stresses and disturbances.” They then go on to show that between sites that are differentially grazed, the dominant species are functionally diverse (filling different functions), and that grazing affects some dominant species negatively, in which case minor species that are functionally similar, but can withstand grazing replace them. Thus a combination of functional diversity and diversity of redundant species allows that ecosystem to maintain function across different grazing regimes.

So in answer to 1) it seems that ecosystems can be resilient to stresses or shocks if the perturbation affects a subset of the species differentially. That is, an ecosystem is less likely to be resilient to a stress that affects all species in a severe way similarly. Secondly, (2) the ecosystem function is produced through a range of species that fill different functions, and for that function to be resilient the ecosystem requires species that are functionally redundant but have differing sensitivities to stress. These two different aspects of diversity are termed species diversity of “effects” on ecosystem function and species “diversity of response” to stress (Folke [and Steve Carpenter] et al. 2004). In this case, resilience of ecosystem function does appear to be an emergent property of diversity as it would not be resilient if only a small selection of species were present. It is due to complexity that the ecosystem is resilient.

These papers are found here:

http://www.public.asu.edu/~akinzig/walker.pdf

http://www.colorado.edu/AmStudies/lewis/ecology/ecobiodiver.pdf

Previously Jessica Newman wrote:

The Cambridge Group brought up the idea of functional diversity and redundancy as being key to ecosystem resilience. I've attached a 2009 Nature article by Wittebole et al. that treats the biodiversity-functioning theory by examining initial species evenness. This is just the tip of the iceberg in the functional diversity/redundancy literature, but I remember liking this article (probably because it's short and sweet). The abstract is below.

 

"Owing to the present global biodiversity crisis, the biodiversity–stability relationship and the effect of biodiversity on ecosystem functioning have become major topics in ecology1–3. Biodiversity is a complex term that includes taxonomic, functional, spatial and temporal aspects of organismic diversity, with species richness (the number of species) and evenness (the relative abundance of species) considered among the most important measures4,5. With few exceptions (see, for example, ref. 6), the majority of studies of biodiversity-functioning and biodiversity–stability theory have predominantly examined richness7–11. Here we show, using microbial microcosms, that initial community evenness is a key factor in preserving the functional stability of an ecosystem. Using experimental manipulations of both richness and initial evenness in microcosms with denitrifying bacterial communities, we found that the stability of the net ecosystem denitrification in the face of salinity stress was strongly influenced by the initial evenness of the community. Therefore, when communities are highly uneven, or there is extreme dominance by one or a few species, their functioning is less resistant to environmental stress. Further unravelling how evenness influences ecosystem processes in natural and humanized environments constitutes a major future conceptual challenge."

An additional note to add on as a suggestion for clarification within the text:

As in previous chapters, the content is supported through an example case.  In this chapter New Orleans appears several times in the the section. 

As a reader and learner of the content, it might be helpful to present the case in its entirety, highlighting the key components of the chapter.   Then, as you work through the chapter,  discuss the specific points of vulnerability, resilience, etc. as they relate to specific examples in the previously outlined case. 

Just as a formatting preference, it may also be helpful to readers if they are guided through the chapter.  An example would be on page 3, vulnerability is identified as having 3 subcomponents: exposure, sensitivity and resilience/ coping capacity.

The first paragraph directly corresponds to exposure, but there are no subsequent paragraphs that clearly lend themselves to sensitivity or resilience.  As a reader, I was looking for these "scaffolds" to assist me and actually went back to look for them to see if I had missed something.   Subheading for each of the three subcomponents would make it easier to read and also to convey the information.

Previously Matthew Gilbert wrote:

Continuing on from Jessica's comment....

Is resilience an emergent property of diverse ecosystems?

 

After the session on Monday (the Cambridge group) questioned whether resilience was an emergent property of human systems (due to high complexity), but not environmental systems. Therefore, was it a misnomer to be asking about emergent properties of CHES when the environment may not have emergent properties? (maybe our discussion wasn’t quite as polar as that).  

 

This is my response – a brief summary of the ecological literature.

 

Three things need to be clarified to ask this question properly: 1) Does the type of stress/shock that the ecosystem could be resilient too play a major role in the answer? 2) What is the mechanism of the emergent property? The answer likely being related to functional diversity and redundancy, and 3) It is important to distinguish that much of the ecological literature has been focused on a slightly different (emergent?) property of diverse ecosystems, that of diverse ecosystems having higher biomass productivity.

 

 A great article on this is Walker et al. [including Ann Kinzig 1999 Plant attribute diversity, resilience, and ecosystem function: the nature and significance of dominant and minor species. Ecosystems 2: 95-113] where they suggest that “many of the minor species [in an ecosystem] are analogues of the dominants [species] in terms of the ecosystem functions they perform, but differ in terms of their capabilities to respond to environmental stresses and disturbances.” They then go on to show that between sites that are differentially grazed, the dominant species are functionally diverse (filling different functions), and that grazing affects some dominant species negatively, in which case minor species that are functionally similar, but can withstand grazing replace them. Thus a combination of functional diversity and diversity of redundant species allows that ecosystem to maintain function across different grazing regimes.

 

So in answer to 1) it seems that ecosystems can be resilient to stresses or shocks if the perturbation affects a subset of the species differentially. That is, an ecosystem is less likely to be resilient to a stress that affects all species in a severe way similarly. Secondly, (2) the ecosystem function is produced through a range of species that fill different functions, and for that function to be resilient the ecosystem requires species that are functionally redundant but have differing sensitivities to stress. These two different aspects of diversity are termed species diversity of “effects” on ecosystem function and species “diversity of response” to stress (Folke [and Steve Carpenter] et al. 2004). In this case, resilience of ecosystem function does appear to be an emergent property of diversity as it would not be resilient if only a small selection of species were present. It is due to complexity that the ecosystem is resilient.

 

 

These papers are found here:

http://www.public.asu.edu/~akinzig/walker.pdf

http://www.colorado.edu/AmStudies/lewis/ecology/ecobiodiver.pdf

 

 

 

Previously Jessica Newman wrote:

The Cambridge Group brought up the idea of functional diversity and redundancy as being key to ecosystem resilience. I've attached a 2009 Nature article by Wittebole et al. that treats the biodiversity-functioning theory by examining initial species evenness. This is just the tip of the iceberg in the functional diversity/redundancy literature, but I remember liking this article (probably because it's short and sweet). The abstract is below.

 

"Owing to the present global biodiversity crisis, the biodiversity–stability relationship and the effect of biodiversity on ecosystem functioning have become major topics in ecology1–3. Biodiversity is a complex term that includes taxonomic, functional, spatial and temporal aspects of organismic diversity, with species richness (the number of species) and evenness (the relative abundance of species) considered among the most important measures4,5. With few exceptions (see, for example, ref. 6), the majority of studies of biodiversity-functioning and biodiversity–stability theory have predominantly examined richness7–11. Here we show, using microbial microcosms, that initial community evenness is a key factor in preserving the functional stability of an ecosystem. Using experimental manipulations of both richness and initial evenness in microcosms with denitrifying bacterial communities, we found that the stability of the net ecosystem denitrification in the face of salinity stress was strongly influenced by the initial evenness of the community. Therefore, when communities are highly uneven, or there is extreme dominance by one or a few species, their functioning is less resistant to environmental stress. Further unravelling how evenness influences ecosystem processes in natural and humanized environments constitutes a major future conceptual challenge."

 

I agree with Matthew's suggestion about hurricane Katrina. I know there was discussion about radically restructuring the chapter, but even if that is done I think Katrina could serve as a useful example of all the major themes involved here (regardless of which ones you end up giving the most focus in the chapter): resilience, vulnerability, emergent properties, CHES, tipping points, etc. I can't, in fact, think of another example--particularly a recent one that will resonate with readers--that so clearly ties into all of these things. So I think it would be instructive to really delve into the Katrina story a bit to illustrate these different ideas. 

That's all... 

Previously Matthew Aruch wrote:

An additional note to add on as a suggestion for clarification within the text:

As in previous chapters, the content is supported through an example case.  In this chapter New Orleans appears several times in the the section. 

As a reader and learner of the content, it might be helpful to present the case in its entirety, highlighting the key components of the chapter.   Then, as you work through the chapter,  discuss the specific points of vulnerability, resilience, etc. as they relate to specific examples in the previously outlined case. 

Just as a formatting preference, it may also be helpful to readers if they are guided through the chapter.  An example would be on page 3, vulnerability is identified as having 3 subcomponents: exposure, sensitivity and resilience/ coping capacity.

The first paragraph directly corresponds to exposure, but there are no subsequent paragraphs that clearly lend themselves to sensitivity or resilience.  As a reader, I was looking for these "scaffolds" to assist me and actually went back to look for them to see if I had missed something.   Subheading for each of the three subcomponents would make it easier to read and also to convey the information.

 

 

Previously Matthew Gilbert wrote:

Continuing on from Jessica's comment....

Is resilience an emergent property of diverse ecosystems?

 

After the session on Monday (the Cambridge group) questioned whether resilience was an emergent property of human systems (due to high complexity), but not environmental systems. Therefore, was it a misnomer to be asking about emergent properties of CHES when the environment may not have emergent properties? (maybe our discussion wasn’t quite as polar as that).  

 

This is my response – a brief summary of the ecological literature.

 

Three things need to be clarified to ask this question properly: 1) Does the type of stress/shock that the ecosystem could be resilient too play a major role in the answer? 2) What is the mechanism of the emergent property? The answer likely being related to functional diversity and redundancy, and 3) It is important to distinguish that much of the ecological literature has been focused on a slightly different (emergent?) property of diverse ecosystems, that of diverse ecosystems having higher biomass productivity.

 

 A great article on this is Walker et al. [including Ann Kinzig 1999 Plant attribute diversity, resilience, and ecosystem function: the nature and significance of dominant and minor species. Ecosystems 2: 95-113] where they suggest that “many of the minor species [in an ecosystem] are analogues of the dominants [species] in terms of the ecosystem functions they perform, but differ in terms of their capabilities to respond to environmental stresses and disturbances.” They then go on to show that between sites that are differentially grazed, the dominant species are functionally diverse (filling different functions), and that grazing affects some dominant species negatively, in which case minor species that are functionally similar, but can withstand grazing replace them. Thus a combination of functional diversity and diversity of redundant species allows that ecosystem to maintain function across different grazing regimes.

 

So in answer to 1) it seems that ecosystems can be resilient to stresses or shocks if the perturbation affects a subset of the species differentially. That is, an ecosystem is less likely to be resilient to a stress that affects all species in a severe way similarly. Secondly, (2) the ecosystem function is produced through a range of species that fill different functions, and for that function to be resilient the ecosystem requires species that are functionally redundant but have differing sensitivities to stress. These two different aspects of diversity are termed species diversity of “effects” on ecosystem function and species “diversity of response” to stress (Folke [and Steve Carpenter] et al. 2004). In this case, resilience of ecosystem function does appear to be an emergent property of diversity as it would not be resilient if only a small selection of species were present. It is due to complexity that the ecosystem is resilient.

 

 

These papers are found here:

http://www.public.asu.edu/~akinzig/walker.pdf

http://www.colorado.edu/AmStudies/lewis/ecology/ecobiodiver.pdf

 

 

 

Previously Jessica Newman wrote:

The Cambridge Group brought up the idea of functional diversity and redundancy as being key to ecosystem resilience. I've attached a 2009 Nature article by Wittebole et al. that treats the biodiversity-functioning theory by examining initial species evenness. This is just the tip of the iceberg in the functional diversity/redundancy literature, but I remember liking this article (probably because it's short and sweet). The abstract is below.

 

"Owing to the present global biodiversity crisis, the biodiversity–stability relationship and the effect of biodiversity on ecosystem functioning have become major topics in ecology1–3. Biodiversity is a complex term that includes taxonomic, functional, spatial and temporal aspects of organismic diversity, with species richness (the number of species) and evenness (the relative abundance of species) considered among the most important measures4,5. With few exceptions (see, for example, ref. 6), the majority of studies of biodiversity-functioning and biodiversity–stability theory have predominantly examined richness7–11. Here we show, using microbial microcosms, that initial community evenness is a key factor in preserving the functional stability of an ecosystem. Using experimental manipulations of both richness and initial evenness in microcosms with denitrifying bacterial communities, we found that the stability of the net ecosystem denitrification in the face of salinity stress was strongly influenced by the initial evenness of the community. Therefore, when communities are highly uneven, or there is extreme dominance by one or a few species, their functioning is less resistant to environmental stress. Further unravelling how evenness influences ecosystem processes in natural and humanized environments constitutes a major future conceptual challenge."