The next 9 blog posts will summarize my reading assignments for the EBIO 3rd semester exam. The exam is scheduled for 3 hours and involves my four committee members asking me questions about anything at all! I was required to put together a reading list covering 4 main topics: biological soil crusts & drylands, microbial ecology, ecosystem services, and community, restoration, and disturbance-succession ecology. Obviously, I actually have 7 topics, which I managed to squeeze into "4". The reading list is a guide for the exam. To help me through this exam preparation process, I will use these blogs to summarize what I am learning over the next 9 weeks.Environmental variability (pros and cons)
My last 6 readings of the restoration ecology section were assigned by Laura Dee, a faculty member who specializes in ecosystem services. They are all recent publications and most had a controversial message. Two of the papers presented frameworks for ecological stability. Stability is an important concept because it is generally what we hope ecosystems will have in the face of disturbances. Disturbances can be of many types and so they have different magnitudes, directions, frequencies, and variability over time. In response to a disturbance, ecosystems can have at least 5 different qualities that contribute to their overall stability: resistance, resilience, variability, robustness, and persistence. Donohue et al. (2016) suggest that studies need to address all of these components (multidimensional perspective) so that we have more continuity across fields for what "stability" actually means. This paper has grounding in policy, motivated by the idea that policy can be improved by more direct language and linkages to underlying science. This paper was also super useful because it showed theoretical graphs of disturbances (presses and pulses) compared to actual measured disturbances for wildfire, nitrogen deposition, and disease outbreaks. None of the real disturbances matched the simple theoretical versions. Alternatively to this, Ninmo et al. (2015) take a resistance-resilience framework (only two components of Donohue's framework). For Ninmo, resistance and resilience can be measured at any biological level (a single molecule, individual organisms, or communities). In this paper, resistance and resilience are actually calculated (based on an initial condition) and then graphed. In relation to the last blog post, one might expect a shift to an alternative stable state when the resistance and resilience of the system are both low. There are some limitations to their approach, but overall, the framework allows us to predict how certain traits of species, populations, or communities might respond to disturbance, which is super useful. Donohue's paper indicates that there is a lot of scientific evidence that biodiversity loss reduces productivity and other resource utilization rates. At the same time, though, we do not know the mechanisms for how biodiversity affects ecosystem services. In Bullock et al. (2011) this is even more clear. They discuss how restoration for biodiversity and for ecosystem services should be two separate endeavors since the links between the two are not certain and not always positive. It may be that restoration goals for these two will align but sometimes they will conflict. Cost-benefit analysis is recommended and they encourage researchers to consider how Payment for Ecosystem Services (PES) could fund restoration. This approach is limited because we really do not have good documentation of how much restoration costs. Of 200,000 restoration case studies, only 96 had associated cost information. This approach is also complicated because you have to be able to value every part of the process, you need willing buyers and sellers, there may be a skew to certain types of services and not others, and there may be inequities in the implementation. Who gives up land? Who benefits from the service? One of the controversial papers I read was lead by the Chief Scientist of the Nature Conservancy, Hugh Possingham (2015). In this paper, Possingham addresses the common perception that land protection is preferable to restoration for conservation goals. The mainstream view is that protection leads to superior outcomes, is associated with lower costs, and has no time delay. Using some simple models, the authors show that in some cases restoration is better than protection. In their example, after 30 years a restoration approach did not have as much protected land, but it did have less degraded land compared to the protection approach. Importantly, throughout their models, it was never optimal to fund both protection and restoration at the same time. Sometimes it was best to protect for some time (say 20 years) and then switch to restoration. The field of restoration ecology would really like to move toward prediction (being able to use a model to make decisions in a scientific way) and this was a step in that direction. The other controversial paper I read touched on the common perspective that we should increase monitoring for conservation. This is a dominant idea in the science-policy reports I read. We need more monitoring! McDonald-Madden et al. (2010) show how someone can use a decision tree to guide decisions about monitoring. Sometimes monitoring can yield unforeseen outcomes with broader impacts that initially intended. On the other hand, monitoring can be very expensive and not worth the effort. Sometimes I think about this for the herpetology monitoring I did in Southwestern WY for two summers. We were able to regularly find amphibians (since they are concentrated in particular habitats at certain times of the year), but snakes were rare. I shudder to think about who may be using that data now as a baseline for future herpetological surveys...no snakes in the area in 2014, and no snakes now. The last paper on this list introduced the term "recovery debt". In their meta-anlaysis of 350 studies, Moreno-Mateos (2017) showed that during recovery there are 50% fewer organisms, 30% less diversity, 35% less carbon and nitrogen cycling. These differences are known as the recovery debt and the authors argue that restoration/offsetting are inadequate to ecosystem protection (an opposite view from Possingham et al. above). In the studies they looked at, the authors found that restoration takes 22 years on average and that recovery from anthropogenic disturbances are worse than recovery from natural disturbances (on multiple measures). Overall, restoration literature is very interesting to me. I like that some people approach it with math, others with theory, and others with applied experience. In EBIO at CU, there is a restoration club that guides volunteers and students on restoration efforts throughout the year. I look forward to the end of the pandemic when I can get involved and see restoration efforts for myself. It is one thing to read these papers and theorize about how ecosystems work. It is another to be in it, pulling each weed, one by one. References McDonald-Madden E, Baxter PWJ, Fuller RA, Martin TG, Game ET, Montambault J, Possingham HP (2010) Monitoring does not always count. Trends in Ecology and Evolution, 25(10):547–550. https://doi.org/10.1016/j.tree.2010.07.002 Nimmo DG, Nally R Mac, Cunningham SC, Haslem A, Bennett AF (2015) Vive la résistance: Reviving resistance for 21st century conservation. Trends in Ecology and Evolution, 30(9):516–523. https://doi.org/10.1016/j.tree.2015.07.008 Possingham HP, Bode M, Klein CJ (2015) Optimal Conservation Outcomes Require Both Restoration and Protection. PLoS Biology, 13(1):1–15. https://doi.org/10.1371/journal.pbio.1002052 Donohue I, Hillebrand H, Montoya JM, Petchey OL, Pimm SL, Fowler MS, Healy K, Jackson AL, Lurgi M, McClean D, O’Connor NE, O’Gorman EJ, Yang Q (2016) Navigating the complexity of ecological stability. Ecology letters, 19(9):1172–1185. https://doi.org/10.1111/ele.12648 Bullock JM, Aronson J, Newton AC, Pywell RF, Rey-Benayas JM (2011) Restoration of ecosystem services and biodiversity: Conflicts and opportunities. Trends in Ecology and Evolution, 26(10):541–549. https://doi.org/10.1016/j.tree.2011.06.011 Moreno-Mateos D, Barbier EB, Jones PC, Jones HP, Aronson J, López-López JA, McCrackin ML, Meli P, Montoya D, Rey Benayas JM (2017) Anthropogenic ecosystem disturbance and the recovery debt. Nature Communications, 8:8–13. https://doi.org/10.1038/ncomms14163
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AuthorSierra is a graduate student in the Barger Lab at CU Boulder studying microbial ecology for dryland restoration. Archives
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