Novel Ecosystems

BRIEF INTRODUCTION

This blog is intended to discuss relevant publications and ideas related to “novel ecosystems” research and management. I expect that through the open, rational and informed discussion of this topic we can generate a better knowledge around the management of these “new ecological entities”.

Novel Ecosystems is a term that was formally proposed by Ricard Hobbs and others in 2006. This publication more or less mark the beginning of a still-ongoing debate in invasion ecology. See a great compendium and examination of  the origins and evolution of the “novel ecosystems” term in this book chapter by Joseph Mascaro.

After the publication by Hobbs et al in 2006, and apart from seminal papers discussing the managerial issues of adopting the term -and the ecological aspects of accepting novel ecosystems definition in the conservation agenda- (papers like Davis et al Nature 2011 and responses about it  definitely raise a debate around this issue), many other investigations have emerged presenting ecological information (i.e. ecosystems functioning of novel systems) that help understanding the real impacts caused by these “novelties”.

This blog will present an updated summary of such publications and will try to highlight the main conclusions within these scientific products that can be used for better and more efficient managerial practices.

Ariel Lugo from University of Puerto Rico and USGS has a significant amount of publications around the topic. This opinion article summarizes many of his own work and others regarding novel ecosystems.

Is the overall debate still necessary?….or should we accept that ecosystems are changing due to human influences and therefore take the necessary actions for good managerial practices regarding ecological novelties?

I am personally interested in answering the second question by generating ecological information about ecosystems dominated by non-native species (i.e. fall under novel ecosystems definition) in the Galapagos Islands. My expectation overall is to generate rigorously-generated  scientific information about the ecology of dominant non-native plants in this world famous archipelago that  can be used by managers to take the best possible decisions regarding the sustainability of this fragile and unique biome.

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Discussions on invasive plant species issues

Native and invasive plants of the Galapagos class-APR 2015

Below you will find comments on main topics regarding native and invasive plant species management, focused mainly on the Galapagos. These comments are uploaded by students from the “Ecology and management of native and introduced plants of the Galapagos” class, that I am currently teaching in this archipelago.

First, below we are commenting on two papers one by Castro et al 2010 and the other by McKinney 2008 regarding the issue of homogenization on islands caused by human related activities including the introduction of invasive species.

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4 thoughts on “Novel Ecosystems

  1. Summary of Readings for 4-01-2015
    Susie Proctor, Taylor Nelsen, Carmen Atawater, Ellen Keuberwitz, Darcey Camp, Rob Wright

    Summary of Castro et al. Paper

    In this study, the research group compared trends of homogenization of plants among archipelagos in the Pacific and Atlantic Oceans. They found that throughout time homogenization has been increasing world wide due to increasing globalization of humans. Homogenization was found to be greater in Atlantic archipelagos than those in the Pacific due to earlier colonization of the Atlantic islands and their decreased distance in relation to one another. They also that homogenization of vascular plants was higher compared to other taxa, showing homogenization is not as simple as it seems.

    Summary of McKinney Paper

    Introducing species in isolated and distant areas causes homogenization between the two areas because they don’t have species in common, but introduced species will cause commonality. In areas where the ecosystems are similar and closer together, adding new species will more likely cause differentiation. Homogenization of two areas involves introduction of invasive species, often leading to extinction of endemic species. Usually homogenization increases over time and is caused more by introduction than extinction.

  2. Devin Beck, Andrew Freedman, TJ Haltigan, Cori Lopazanski, Ezra Mendales, Bryan Reatini, Erin Vanderjeugdt

    Homogenization is achieved through the introduction of non-native species along with the successive extinction of local native species. The structure of an archipelago, like the Galapagos archipelago, increases the likelihood for endemism, and translocation by humans is one of the most important drivers for homogenization. This is a particularly major factor when considering the travel and transport to and among the Galapagos Islands. When introduced, non-native species are a much greater driver for homogenization than competition between native species, but this aspect also depends on two major factors: space and time. One thing that can be said is that homogenization “almost certainly increases with time,” meaning that homogenization will always occur even at a very slow rate. Furthermore, if you introduce a species within a small spatial scale such as between neighboring islands, homogenization is less likely to occur than if the species is transferred from a more distant ecosystem.

  3. Maddie, Lena, Megan, Heather, Laura, Maria, and David wrote:

    The paper by Castro et al. (2010) is an example of homogenization on a large temporal and spatial scale on archipelagos. They found that more homogenization had occurred in the Atlantic archipelagos than Pacific, likely because of a longer history of population and trade. This paper also concluded that invasions more than extirpations created homogenization. This is a teleconnected process because the same homogenization pattern is seen over a wide geographic area. Overall, all 12 archipelagos over 2 oceanic systems showed an increase in compositional similarity, consistent with the theme of biological homogenization.

    McKinney’s (2008) paper is a review of biological homogenization, largely taxonomic, in relation to ungulate populations. He states that it would be important to study abundance of shared and unshared species between areas. The results of a study on homogenization should depend on the spatial scale, in that closer ecosystems may be more similar than more separated ecosystems. He emphasizes that homogenization is based more on introductions than on extirpations or extinctions. It is also important that past studies on homogenization do not include enough information on changes in community composition on a large enough time scale.

  4. Alanna, Calli, Karli, Alyssa, Bryce, Torrie, Erin commented:

    Biological homogenization can occur in two major ways: through the introduction of invasive species or through increased extinction of endemic species. Homogenization can be measured in many ways. There is genetic homogenization (mixing exotic genes into the native gene pool), functional homogenization (increase in similarity of ecological roles between communities), and–most commonly used–taxonomic homogenization (relative gain of number of shared species between two areas).

    There are many complexities involved when assessing human impact on biological homogenization. Firstly, it is difficult to compare homogenization between existing communities with little knowledge of the past community composition. Second, it is difficult to compare communities distant from each other since their initial compositions share few (if any) native species. Since their initial compositions are so different and they have few or no shared native species, introduced species would have a drastic homogenizing effect. However, neighboring communities where species have been introduced tend to have fewer shared species than shared native species.

    General trends synthesized by McKinney (2008) are that homogenization increases over time and that this is driven primarily by the introduction of invasive species instead of native species extinctions. Future study will need to be done as human urbanization grows; conservation from homogenization is extremely important because we’ll lose so much biodiversity and genetic information.

    Castro et al (2010) studied “floristic homogenization,” the increased similarity of the flora of a particularly region/ecosystem, in oceanic archipelagos including the Galapagos Islands. Islands are sensitive indicators of biological change, making it a great study site to observe plant homogenization. He conducted pairwise comparisons between “original” flora (pre-European colonization) and current flora of each region. It is a “teleconnected process” (linked pattern that spans large geographical areas); so as more non-native species are introduced by humans, they invade and change the environment so that it’s more homogenized. They found that archipelagos became much more similar in composition over time, indicating that biotic homogenization is a teleconnected process driven by human translocation. However, trends were not uniform across regions or species. They also concluded that invasions have a larger impact than extirpations as drivers of biotic change

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