Dornelas et al. 2014 by K. Sullivan

Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss

Blog by: Kaitlyn Sullivan

Authors:

·       Marie Dornelas

“My research focuses on quantifying biodiversity and understanding the processes that shape it. I often work on tropical systems and specifically coral reefs, but I also work with tropical freshwater fish, mangrove crabs and plants for example, as I am more question-driven that organism-driven. I like to combine ecological theory, synthesis of existing data, and fieldwork (preferably in exotic places!) in my research, and most of the research questions I’m interested in fall under the disciplines of community ecology, macroecology and biogeography. I tend to work on intermediate spatio-temporal scales (that is communities and networks of communities over time-scales of years to tens of years).”

https://synergy.st-andrews.ac.uk/diversity/dr-maria-dornelas/

·       Nicholas J. Gotelli

“My research addresses basic questions about the organization of animal and plant communities. What are the forces that determine the species composition and abundance of natural assemblages? How do competition and predation affect local community structure? What are the biotic and abiotic factors that control population growth and the risk of extinction? Current research projects include enrichment and tipping points in aquatic ecosystems, effects of climate change on ant assemblages of eastern deciduous forests, and null model analyses of community structure and biodiversity.”

http://www.uvm.edu/~ngotelli/homepage.html

·       Brian McGill

“I study questions pertaining to biodiversity at large scales – large areas of space, long periods of time, many species. These questions have been deemphasized in ecology due to the difficulty in doing experiments, but are of high relevance to conservation and management questions. I have two broad research questions. One is developing the ability to predict how species ranges will respond to climate change. The other is finding ways to measure the impact of humans (especially land cover change) on community structure.”

https://sbe.umaine.edu/mcgill/

·       Hideyasu Shimadzu

“My general research interest is in the science of data, Data Science. Data and models - measurement and description of phenomena - they have been the foundation of modern sciences. For the last several years my research activities lie on the intersection of statistics and subject matter sciences, with a particular focus on environmental/ecological sciences. My research concerns how statistical consideration contributes to advancing our knowledge and understanding of phenomena of interest.”

http://shimadzu.datascience.jp/

·       Faye Moyes

Is currently a research assistant for the School of Biology at the University of St. Andrews.

·       Caya Sievers

Is currently a Seal Diet Technician for the School of Biology at the University of St. Andrews.

·       Anne E. Magurran

Is currently a Professor for the School of Biology at St. Andrews.  “I am interested in the measurement, evolution and conservation of biological diversity with particular emphasis on freshwater fish assemblages and currently have projects in Brazil, Trinidad, Mexico, India and Scotland.”

]https://risweb.st-andrews.ac.uk/portal/en/persons/anne-magurran(4b27832d-6f10-48f3-9fe8-ac4b8bec6958).html

Summary

                  Losses or reductions in biodiversity are likely the result of habitat destruction, pollution, overharvesting, invasive species, as well as changes in climate.  However, the degree to which changes in biodiversity has occurred overtime is poorly understood.  The main purpose of this paper is to address “how diversity within assemblages is changing through time”.  To better understand the extent to which global biodiversity is impacted by changes in local biodiversity assemblages, data collected between 1874 to present, consisting of 6.1 million species occurrence records (35,613 species) from 100 individual time series from biomes across the entire globe were analyzed.  To quantify patters of temporal diversity, α was used to measure changes in local diversity, while β was used to measure changes in community composition. 

                  Due to undeniable changes in habitat and unusually high extinction rates, they hypothesized that “most assemblages would exhibit a decrease in α (local) diversity through time.  As for changes in community composition, they hypothesized that because of “long-term changes in species composition, we expect[ed] increasers in temporal β diversity”.

                  The results from the time series collectively indicate no such systematic change in temporal α diversity as was predicted.  However, as for temperate assemblages, the average trend in α diversity was positive, while the trend tended to be negative at the global scale.  The opposite is true of the trends regarding temporal β diversity, which increased relative to the baseline sample “across all climatic regions, realms, and taxonomic groups.”  They addressed these finding by stating that their “results suggest that local and regional assemblages are experiencing a substitution of their taxa, rather than a systematic loss.”