ecosystem importance: protecting diversity (Introduction)

by David Turell , Monday, May 23, 2022, 18:33 (703 days ago) @ David Turell

An alarmed study to analyze impending diversity loss:

https://ecoevocommunity.nature.com/posts/anticipating-changes-in-biodiversity-on-an-inc...

"Human activity is producing an extensive and persistent effect on Earth. The accumulating evidence of changing disturbance regimes linked to human activity is alarming. Large shifts in features of individual disturbances and disturbance regimes are occurring, with further changes predicted for the future. Indeed, climate change and the increasing frequency of extreme weather events, urban air pollution, and contamination of oceans by plastic waste have dramatically raised awareness that both biodiversity and the human civilization face an existential environmental crisis. For example, wildfires have increased in area, intensity and frequency over the last two decades, impacting human lives, crops, and biodiversity. Twenty of the hottest years in history have occurred in the past 22 years, and extreme events like heat waves are projected to increase in frequency by more than an order of magnitude as climate change continues. All these changes in disturbance regimes are occurring concurrently with anthropogenic alternations of the global ecosystem such as global rises in temperatures, increased mass pollution events, deforestation and defaunation of ecosystems, and more wildland conversion for human use. Some, if not all, of these trends are expected to continue, while it is also likely that new disturbance regimes will arise, including the possibility of new types of disturbances that involve plastics, toxins, and agricultural chemicals. Although these trends seem inevitable in the short term, the design of mitigations strategies or policies for conservation could benefit from frameworks that can anticipate biodiversity changes under disturbed regimes.

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"In ecology, disturbance is an event in time that disrupts the structure of a community by changing resources, substrate availability, or the physical environment. It is considered a major factor influencing biodiversity. While a disturbance may result in inhibition, injury, or death for some individuals in a community, it also creates opportunities for other individuals to grow or reproduce. Further, disturbances can profoundly alter trajectories of ecosystem dynamics and lead to unpredictable or undesired ecosystem responses. Indeed, how disturbance relates with stochastic and deterministic assembly mechanisms remains largely unknown, particularly under fluctuating disturbances. Given the growing human population and its impact on natural and engineered ecosystems, management and conservation practices are faced with increasing frequencies and magnitudes of various disturbances that occur on different scales. However, despite increases in the frequency, duration, and scale of disturbance events, predicting the outcome of disturbance remains a challenge. Thus, understanding how or why disturbances might enhance or reduce ecosystem vulnerability is an important area of concern as ecosystems are faced with rapid-paced environmental changes. (my bold)

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"In a nutshell, we found stochastic assembly processes to be more important at intermediate disturbance frequencies where the highest α-diversity was also observed, together with high β-diversity dispersion across within-treatment replicates as predicted by the ISH. Furthermore, we observed that a peak in the relative contribution of stochasticity preceded the formation of a peak in α-diversity across a disturbance frequency range. This means that community assembly patterns during succession under disturbance can act as an early warning of upcoming patterns in diversity. Plus, stochastic assembly operating at intermediate levels of disturbance could be the reason why higher diversity does not necessarily mean better function. While these findings are encouraging, further research in a variety of ecosystems and scales is needed to validate the broad applicability of the ISH, which is why we encourage the scientific community to explore this framework." (my bold)

Comment: while not exactly on my point about the importance of diverse ecosystems and possible damage, the authors are developing a formula for future study and I've skipped that portion of the paper. What is clear is the degree of alarm. dhw's tunnel view of humans and their food simply tries to remove the problem from consideration. Life must have a diverse food supply at all times, all during the process of evolution. Viewed from the position of a progressive designer, he would understand the problem, provide a very diverse bush of complex ecosystems all through evolution from bacteria until the final arrival of an anticipated huge human population, huge because of the human extraordinary mental capacity. In dhw's view God dawdled along the way instead of getting right to it. What history presents is what I accept as God's doing. From that viewpoint, it makes perfect sense to a believer but apparently not to an outsider.