For my first blog post I chose an article, actually a letter, from the highly acclaimed journal Nature. Nature is a multidisciplinary journal and it is very easy to get lost in the land of science when reading the titles of the articles in each edition. Luckily my brain is tuned to search out phrases like “human disturbance” and “diversity loss” and I quickly found this letter written by A. S. MacDougall with input from R. Turkington, K. S. McCann and G. Gellner titled ‘Diversity loss with persistent human disturbance increases vulnerability to ecosystem collapse’. Any young ecologist would find it difficult to not at least read the abstract. Upon doing so, I learned that the authors embarked on a 10 year experiment aimed at finding empirical evidence that a combination of environmental change and a loss in diversity increases the risk of an ecosystem collapse. My interest was piqued.
In my modest look into the world of ecology I have stumbled across multiple instances where a team of researchers focuses on a question that is easy to answer with a vague reference to some aspect of ecology that is difficult to test but important to assume. In many cases this leads to a necessity for generalisations and perhaps even a picking-and-choosing of relevant information, irrespective of context. These aspects usually involve a host of, in my opinion, vague references. Ecologists, and perhaps all natural scientists, are constantly being forced to build a world on assumptions and uncertainties in order to make one aspect of our understanding of complex systems more certain. The search for answers, and certainty, is why we do what we do. MacDougall et al state that theory predicts that a combination of environmental change and diversity loss increase the risk of abrupt and potentially irreversible ecosystem collapse. The letter cites six papers supposedly deal with this.
Ives and Carpenter (2007), Hooper et al. (2012) Loreau (2010), Barnosky et al. (2012), Kéfi et al. (2007), and Rietkerk et al. (2004) deal with a many aspects of the theory with some small scale empirical studies, and many commentaries on the state of the ecosystems but little comment based on in situ observations of ecosystem collapse as a result of environmental change or biodiversity loss. This is where MacDougall et al really grabbed my attention. Conducting a 10 year experiment of this nature is no mean feat and the results that this experiment yields are on a scale that surpasses most of those mentioned in the literature. All the models in the world are useless without experiments such as these.
There is no doubt that the results of the experiment are interesting. The finding that a negative relationship between diversity and function exist, begs me to ask, what we are actually conserving for? I often find myself wondering what humans are conserving for. Are we conserving out of nostalgia and fear of change or are we conserving our environment in order to better sustain ourselves? Where is the line dividing us from our environment? I grew up on the Gauteng Highveld surrounded by grassland and a large portion of my undergraduate studies dealt with fire regimes in Savanna and Grassland ecosystems. I find the idea of managing with fire interesting as the line dividing humans from being a part of the ecosystem to managers of the ecosystem becomes examinable. MacDougall et al examined the relationship between an altered and diversity poor ecosystem and vulnerability to collapse in degraded but species rich pyrogenic grassland; however, I did not find that the letter set the information into any real world context. The main findings of this experiment verified the theory that biodiversity is functionally significant in pyrogenic ecosystems, as grasslands with greater native species diversity were able to resist woodland invasion after a fire. While the monoculture low diversity areas were unable to stand up to the harsh introduction of a fire regime.
Although the article verifies some very important theory about managing grassland with fire, I felt that many aspects of the bigger questions were left out of the paper. The main benefit that I believe I received from this paper is contemplation into the roles we as humans play in our environment. The diversity-stability debate was not one I had considered before and it will possibly shape many of the conclusions I draw when debating conservation issues. I find myself led on to ask more and more questions about the need to conserve biodiversity and the search for mechanistic evidence that the processes we believe to be important are indeed playing the role in the ecosystem that we believe that they are.
One of my honours projects will be focusing on the connectivity of a landscape. The fundamental idea behind connectivity conservation is that in a fragmented landscape a higher level of connectivity allows for survival of metapopulations. My project will tend towards an analysis of scale and measures of connectivity with my faith being placed on the ideas of those before me, mainly that connectivity has importance. I am embarking on this study with the hope that what I find will be of interest to the community and will benefit the science, but generalisations and assumptions will need to be made. The link between metapopulation survival, connectivity and overall survival is mostly a theoretical one, rarely empirically studied. Perhaps real world investigations are too risky and in that regard I commend MacDougall et al. In the end not every question can be answered by any given study and in systems as complex as those found in nature assumptions will always be necessary. As I am beginning my journey into research biology this is an important lesson to learn in order to avoid feeling overwhelmed by the vastness of the unknown. I may have to build my questions on shaky theories and uncertainties, and I may not be able to solve all of the world’s problems, but, like MacDougall et al. perhaps I can shed some light on some cracks and add a measure of certainty so that
Reference
MacDougall A. S., K. S. McCann, G. Gellner, and R. Turkington, 2012. Diversity loss with persistent human disturbance increases vulnerability to ecosystem collapse. Nature 494: 86–89
pan·chres·ton [pan-kres-tuhn]:
noun a proposed explanation intended to address a complex problem by trying to account for all possible contingencies but typically proving to be too broadly conceived and therefore oversimplified to be of any practical use.
One of my honours projects will be focusing on the connectivity of a landscape. The fundamental idea behind connectivity conservation is that in a fragmented landscape a higher level of connectivity allows for survival of metapopulations. My project will tend towards an analysis of scale and measures of connectivity with my faith being placed on the ideas of those before me, mainly that connectivity has importance. I am embarking on this study with the hope that what I find will be of interest to the community and will benefit the science, but generalisations and assumptions will need to be made. The link between metapopulation survival, connectivity and overall survival is mostly a theoretical one, rarely empirically studied. Perhaps real world investigations are too risky and in that regard I commend MacDougall et al. In the end not every question can be answered by any given study and in systems as complex as those found in nature assumptions will always be necessary. As I am beginning my journey into research biology this is an important lesson to learn in order to avoid feeling overwhelmed by the vastness of the unknown. I may have to build my questions on shaky theories and uncertainties, and I may not be able to solve all of the world’s problems, but, like MacDougall et al. perhaps I can shed some light on some cracks and add a measure of certainty so that
Reference
MacDougall A. S., K. S. McCann, G. Gellner, and R. Turkington, 2012. Diversity loss with persistent human disturbance increases vulnerability to ecosystem collapse. Nature 494: 86–89
pan·chres·ton [pan-kres-tuhn]:
noun a proposed explanation intended to address a complex problem by trying to account for all possible contingencies but typically proving to be too broadly conceived and therefore oversimplified to be of any practical use.
