Briland, Ruth D., Stone, Joshua P., Manubolu, Manjunath, Lee, Jiyoung, Ludsin, Stuart A. 2019. Harmful algae. 10.1016/j.hal.2019.03.004

With anthropogenic eutrophication and climate change causing an increase in cyanobacterial blooms worldwide, the need to understand the consequences of these blooms on aquatic ecosystems is paramount. Key questions remain unanswered with respect to how cyanobacteria blooms affect the structure of aquatic food webs, the foraging abilities of higher consumers, and the potential for cyanotoxins (e.g., microcystins [MCs]) to accumulate in fish. Toward addressing these uncertainties, physicochemical attributes, water (for MCs), phytoplankton, zooplankton, and epipelagic and benthic age-0 fish were sampled at 75 sites (44 sites for fish) of varying cyanobacteria concentration (0.1 to 44 µg/L) in western Lake Erie during the cyanobacteria bloom season, 2013-2014. Sites with high cyanobacteria biomass were characterized by Microcystis spp. (84-100% of biomass), detectible levels of MCs (maximum = 10.8 µg/L), and low water transparency (minimum = 0.25 m). Counter to expectations, strong positive relationships were found between cyanobacteria concentration and the biomass of several herbivorous zooplankton taxa (e.g., Daphnia, Diaphanosoma spp., Bosmina (formerly Eubosmina) coregoni, and Calanoida). Expectations regarding fish were partly supported (e.g., diet selectivity varied across a cyanobacteria gradient) and partly not (e.g., consumption of zooplankton did not differ between bloom and non-bloom sites). These findings show that cyanobacterial blooms can strongly affect the distribution, composition, and interactions of zooplankton and fish, sometimes in surprising ways, highlighting the need to further explore their impact on aquatic food webs.

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Open Access, Open Systems: Pastoral Resource Management in the Chad Basin

Mark Moritz, Paul Scholte, Ian M. Hamilton, Saïdou Kari. 2019. Global Perspectives on Long Term Community Resource Management. pp 165-187. DOI: https://doi.org/10.1007/978-3-030-15800-2_8

The discussion about the impact of pastoralists on ecosystems has been profoundly shaped by Hardin’s tragedy of the commons that held pastoralists responsible for overgrazing the range. Research has shown that grazing ecosystems are much more complex and dynamic than was previously assumed and that they can be managed adaptively as commons. However, proponents and critics of Hardin’s thesis continue to argue that open access to common-pool resources inevitably leads to a tragedy of the commons. A longitudinal study that we conducted of pastoral mobility and primary production in the Logone Floodplain in the Far North Region of Cameroon suggests that open access does not have to lead to a tragedy of the commons. We argue that this pastoral system is best conceptualized as an open system, in which a combination of individual decision-making and coordination of movements leads to an ideal free type of distribution of mobile pastoralists. We explain how this self-organizing system of open access works and its implications for theories of management of common-pool resources and our understanding of pastoral systems.