Perhaps this paper might be helpful: https://www.researchgate.net/publication/236866838_Environmental_Dynamics_in_Salinas_Grandes_Catamarca_Argentina

Article Environmental Dynamics in Salinas Grandes, Catamarca, Argentina

Smooth-coated otter (Lutrogale perspicillata sinica) is a semi aquatic mammal depending entirely upon fish (96%). This sub-species is endemic to Pakistan and its Type Locality is Sukkur in Sindh province. Sindh province of Pakistan has a network of canals, water channels, hundreds of freshwater lakes and seepage water lagoons that support this species. Sindh government, through a recent notification, has allowed every one for fishing from every where in the province and there is no license for fishing in Sindh. Now most of the lakes are owned by local influential people who stock the fish seed and harvest annually. So, practically, most of the water bodies have become controlled fish farms. There exists a sever conflict between fish farmers and Smooth-coated otter and the fish farmers in most of the cases have appointed gunmen to protect fish farms from otter attacks. Under such circumstances, Smooth-coated otter have to forage large areas for food by taking life risks in its Type Locality. Food is major factor of a habitat and in this case, a limiting factor. Sindh province have both terrestrial and aquatic habitats.

Steven ... read about mass kill for fish in some areas of river shore 2 months ago. Multicausal event. Cilmate change & sort of pollution

Not sure if exactly the same, but in many systems small and younger individuals can survive at higher rates than older and larger individuals when resources are low. You could say that both small and large have the same resources, but as individuals the larger have higher biomass etc... When resources are low the small individuals require less resources and so outcompete the large. It is based on R* theory of Tilman and has been seen in both experimental Plodia populations and wild European Perch

Kenneth, by high and low resource individuals, I meant resource availability. For example, a high resource site would have and abundant light, water, nutrients. I am wondering if there are examples where the trees on such sites had higher rates of mortality than did individuals from low resource available sites (of the same species, and in relatively close proximity to each other) during episodic stress. I have at least one case study to support this anomaly, but am looking for others.

Thanks Tom, your answer is in line with my question. The only difference would be, if age is a surrogate for size, the would suppressed, low-resource availability individuals (particularly plants) respond to stress in the same way as young plants?

I guess the question is can small plants ever survive better than large plants/trees (intraspecific comparison). Whether they are small because they are young or stunted is maybe not so relevant..... its a cool question but I know little of plants. Maybe speak to Richard Shefferson at UGA, Athens who works on plant demography

Hi Steven, a bit late my answer

but I guess you did not make final conclusions yet. If I understand you right then this is the core sentence of your question: "For example, a high resource site would have and abundant light, water, nutrients. I am wondering if there are examples where the trees on such sites had higher rates of mortality than did individuals from low resource available sites".

I think there are many examples in plants. Many plants are quite specialized in their habitat preferences. Plants that are well adapted to low fertility conditions often do not so well under high nutrient levels. This is something every gardener would be able to confirm. Under such circumstances, a high nutrient availability environment itself can be considered a stress factor, mostly not because of the nutrients but because of a competitive pressure these specialized species cannot cope with. This is obviously also true for light and water. Otherwise all species would thrive equally well or bad under all conditions.

Thanks Tassilo for your response. What about within species response? For example, high elevation spruce. The species is well adapted for cold low nutrient growing conditions. If there are two patches of spruce in close proximity to each other, but one has low nutrient conditions (e.g. because it regenerated on a old high elevation farm) and the other patch grew on more nutrient rich soils (e.g. never farmed). So the low nutrient condition spruce were chronically stressed, while the more nutrient rich spruce were not chronically stressed. Would the growth characteristics from being chronically stressed (e.g., more roots, less foliage) make the low resource patches less susceptible to extreme episodic stress (e.g., drought) compared to the non chronically stressed patches? If so, what are the implications under and increasingly extreme climate event world regarding for health? The rise of the mediocre forest?

Ok, now I get your thought, Steven, and it is an interesting idea. I am not a plant physiologist, although I have done some work related to plant physiology. I think it will be very difficult to generalize an answer to this question. Plants seem to be quite adaptive throughout their lifetime and their root system changes depending on abiotic stresses. Factors like water and nutrient availability are major modifiers of post-embrionic root development and are so constantly as nutrients and water are not equally distributed in soils, as you obviously know. In case of drought, I would assume many factors influence survival, a rock close to the plant might reduce evapo-transpiration, soil texture and composition, the plant community and niotic interactions, the severity and duration of the drought etc. The age and condition of the plant are most likely also quite relevant and plants in good conditions might be fitter than stressed ones. On the other hand, a plant that did not have the resources to fully develop might have a smaller leave area and a slower metabolism and for that reason withstand hostile conditions better. Quite a bit of work has been done on root-nutrient interactions (though mainly with Arabidopsis in labs) and I could imagine that some clues have already been produced. If not I would look at adaptations of different plant species adapted to extreme climates and compare those with the physiological patterns that stressed plans adopt (e.g. number of stomata/area, total evapo-transpiration area, growth rate, root pattern etc). If you find that stressed plants become more like "extremophiles" it is likely that they will also do better under short term shocks.

My experience with grasses is that those on poor soils are generally less tolerant to extreme conditions than those on good soils (same species, same varieties, planted from the same seed harvest). And if you take pests and diseases as another extreme impact, then plants on poor soils are definitely disadvantaged.

Tassilo, what if the stressed and unstressed plants both received a relatively minor additional stress (e.g. 1 month drought)? If the stressed plants experienced some (e.g., 20%) mortality, while the unstressed plants experience no mortality. THEN a second more severe stress (e.g. 3 month drought 6 months later), came along. Could the predisposition for stress and temporary reduction in resource demand associate with the previous 20% mortality in the stressed plants, actually give them an advantage in the more severe drought compared to the unstressed plants? The implication being that in the increasingly climate variable world, stressed plants could better survive compared to what we traditionally consider "healthy forests". If true, the implications for management, and genetic engineering are enormous. I have a paper in review outlining this concept and am looking for feedback on its potential validity.

Uff... that is a complicated scenario with too many unknowns. I don't know and don't dare to give an opinion as it would not be based on anything else than assumptions. I would assume that the stressed plants would still suffer more because in their environment they can also not recover completely from the damage. But this is really only out of the blue. The question however is relevant and some research on it would for sure be worth the effort. But I think this is so elaborate a scenario that you would really have to go to the field and test it.

It has been 4 years since you asked this question, but I just came across it today. Are you still interested in examples?

Yes. More than ever. Unexpected changes are become increasingly common over the past 4 years.

I documented food web dynamics on the Kaibab Plateau in Arizona during 1999-2004 for my dissertation research. On my study area, 2001 and 2002 were drought years, 2003 had the lowest Palmer Drought Severity Index in 100 years, and 2004 had the highest annual precipitation in 80 years. As you can imagine, the dramatic shifts in climate reverberated throughout the northern goshawk food web. For example, prior to the drought, Ponderosa Pine (PIPO) trees in ponderosa forests produced more cones than PIPO trees in mixed conifer forest. However, after 2 years of drought, PIPO trees in mixed conifer forest produced up to twice as many cones as PIPO trees in ponderosa forest. I also documented differences in the densities of prey species among cover types before and after the drought. For more information, please see my dissertation "Reproductive responses of an apex predator to changing climatic conditions in a variable forest environment" and my question "What was the global extent of drought conditions during 2001-2003 and how did it affect the biota?" Both can be accessed through my ResearchGate profile. Please contact me. I am very interested in collaborating on issues related to environmental dynamics. I want to contribute to the development of effective contingency plans for maintaining biodiversity in a more extreme and uncertain future climate.

these days "flash drought" which is sudden water deficit or high evaporative demand of ecosystem is popular as an unexpected event. 2012 summer drought in central plains cause grassland ecosystem collapse for 3-weeks and the slow recovery was achieved.

Susan and Kenneth,

thank you for your input. Specifically, I am interested in unique impacts. By that I mean interactions with climate (and possibly other factors) that caused the ecosystem to respond in a way never before observed.

I cited the red spruce pine beetle/drought/acid rain interaction previously.

In response to Kenneth's question, recent examples include 1) river bottom forest mortality while hill slope trees survived the 2015 Texas drought. Previously, the river bottom trees were immune and the hill slope trees would die. Another example would be the mountain pine beetle crossing the Rockies. This one is not completely unexpected as the climate warms, but it is unique. The question would be how will be beetles interact now that they have crossed? Will they just hit the pines or will they move into other species? Hard to say for sure given that there is no precedent in that region.

Kenneth,

the list you provided is a series of weather events. A change in pattern in these events represents climate change. For example, I have included a link for a site the lists daily global weather records. Of course the data changes daily, but there is a clear pattern of more record highs than lows. That is climate change. http://coolwx.com/record/ Check it over time and you will see the pattern.

Kenneth, what you say is of course true, but the vast majority of the recent change has occurred in the past 40 years. Records are set everyday, but if the climate is just variable (as opposed to variable and trending), then the record highs should equal record lows. That has not been the case for over 20 years. Highs far outweigh lows. My interest is in what previously unseen ecosystem responses are resulting from this shift. We have no antecedent case studies on which to draw, so surprises are very likely. The Earth has seen these changes before (e.g., meteor impact) but we have not.