Novel ecosystems present ecologists with a rare opportunity to expand the science of ecology. Ecological novelty is discussed in this seminar as a quantifiable gradient of change in one or several dimensions. This framework then allows for testing how classical theories (e.g.Island biogeography) hold up to various degrees of novelty, and more importantly to develop new questions that move the field of ecology forward. In this webpage, we will expand on the idea that novel ecosystems present an unforeseen and underutilized opportunity to develop the science of ecology across disciplines. We will use two research articles by Aronson et al. 2014 and McCullough Hennessy et al. 2016, to demonstrate systems where ecological novelty resulted in the exploration of (1) new ways to think of classical research questions and (2) novel ways to solve ecological problems respectively.
Over half of the human population now lives in cities and this is a trend that is expected to be maintained. The authors in Aronson et al. 2014, aim to look at the potential biotic homogenization of 147 cities worldwide. They find that the regional nature of most cities is responsible for reducing global biotic homogenization. They also find that most cities maintain higher diversity of native birds and plants than exotic species. Nevertheless, the density of native species is lower than in peri-urban and rural areas. This example was chosen to demonstrate cities as novel ecosystems and how biotic homogenization can be tested in these systems. While the author recognizes cities as novel ecosystems, there is no way to assess the degrees of novelty of different cities. European cities are in average hundreds if not thousands of years older than western cities, which could be perceived as less novel than cities that have been settled for a few hundred years. This is a challenge that needs to be addressed for the novel ecosystem framework to develop the science of ecology. Are older cities more similar to each other in terms of biotic diversity, or do modern cities have better plans for maintaining biotic diversity or other ecosystem properties? These questions could be expanded upon by a quantitative metric of novelty that considers the characteristics of cities. For example, light pollution levels, the total area of homogeneous yard space, degree of the heat-island effect are several characteristics of cities that can be incorporated into a novelty metric. This metric in turn can be used to assess the effect of novelty on ecosystem properties of interest.
Novel ecosystems can also be used to test experimental approaches that can be applied for conservation or restoration ecology. The authors in McCullough et al. 2016 consider an invaded tallgrass ecosystem as a novel ecosystem, where they aim to reintroduce the ground squirrel (Otospermophilus beecheyi), to improve the habitat opportunity of the western burrowing owl (Athene cunicularia hypugaea). The authors use this novel ecosystem as an opportunity to restore the availability of burrows in the invaded grassland by reintroducing the ground squirrel, mowing and augering the soil without a removal or extermination of the invasive tall grass. They find that the number of burrows was much higher in the auger and mowing plots. They also find that locally, squirrels could maintain tall grasses at low height. This is important for the habitat quality of the burrowing owl and the squirrel. They hypothesize that if squirrels were at higher abundance the effect would be sufficient to maintain the tall grass at low height. The authors argue that this system would resemble a hybrid system, maintaining aspects of novel ecosystems and the native or historical ecosystem. We agree with the authors in this aspect, yet we suggest that this ambivalence of hybrid or novel ecosystem would be resolved with a metric of novelty that can be assessed in a gradient. This approach can facilitate thinking and managing novel ecosystems. If novelty is not a desirable characteristic of a system,management approaches could aim to lower the novelty of a system, instead of eliminating it.
We found that the literature of novel ecosystems is embedded deeply in the conservation and restoration ecology disciplines. We found that in these disciplines rarely novel ecosystems used as an opportunity to explore classic ecological questions or develop new concepts and ideas in ecology. We are interested in why this occurs. We ask, do we know everything we need to know in the field of ecology? Are more people interested in conservation science and not in theoretical ecology? We would like to continue to explore what are the big questions that remain in the field of ecology and to what extent novel ecosystems can be used to address some of these questions. We hope that these ideas will continue to be explored beyond conservation and restoration ecology. This is a continuing conversation that needs to expand beyond our group, and through this medium we look forward to maintain this conversation.
References
Aronson, Myla F. J., Frank A. La Sorte, Charles H. Nilon, Madhusudan Katti, Mark A. Goddard,Christopher A. Lepczyk, Paige S. Warren, et al. 2014. “A Global Analysis of the Impacts ofUrbanization on Bird and Plant Diversity Reveals Key Anthropogenic Drivers.” Proc. R. Soc.
B 281 (1780): 20133330. doi:10.1098/rspb.2013.3330.
McCullough Hennessy, S., D. H. Deutschman, D. M. Shier, L. A. Nordstrom, C. Lenihan, J.-P.Montagne, C. L. Wisinski, and R. R. Swaisgood. 2016. “Experimental Habitat Restorationfor Conserved Species Using Ecosystem Engineers and Vegetation Management.” Animal
Conservation 19 (6): 506–14. doi:10.1111/acv.12266.