A photovoice assessment for illuminating the role of inland fisheries to livelihoods and the local challenges experienced through the lens of fishers in a climate-driven lake of Malawi

Small-scale inland capture fisheries provide an important source of nutritious food, employment and income to millions of people in developing countries, particularly in rural environments where limited alternatives exist. However, the sector is one of most under-valued fisheries sectors and is increasingly experiencing environmental change. This study adopts a Sustainable Livelihoods Approach and investigates how important a fluctuating inland fishery is to livelihoods, and how local perceptions on challenges corresponds to global evidence. Through an innovative participatory method; photovoice, the lived experiences and perceptions of fishers are depicted. The findings illuminate the valuable role of the sector to food and nutrition security and the complex nexus with vulnerability to climate change. The study responds to the call for more local level assessments of the impacts of climate change on inland fisheries in data-limited environments, and the value of the sector in underpinning the Sustainable Development Goals. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01583-1.     

River Basin Export Reduction Optimization Support Tool; a tool to screen options for reducing nutrient loads while minimizing cost

Excess loading of nitrogen and phosphorus to river networks causes environmental harm, but reducing loads from large river basins is difficult and expensive. We developed a new tool, the River Basin Export Reduction Optimization Support Tool (RBEROST) to identify the least-cost combinations of management practices that will reduce nutrient loading to target levels in downstream and mid-network waterbodies. We demonstrate the utility of the tool in a case study in the Upper Connecticut River Basin in New England, USA. The total project cost of optimized lowest-cost plans ranged from $18.0 million to $41.0 million per year over 15 years depending on user specifications. Plans include both point source and non-point source management practices, and most costs are associated with urban stormwater practices. Adding a 2% margin of safety to loading targets improved the estimated probability of success from 37.5% to 99%. The large spatial scale of RBEROST, and the consideration of both point and non-point source contributions of nutrients, make it well suited as an initial screening tool in watershed planning.     

Considerations for using alternative technologies in nutrient management on Cape Cod: Beyond cost and performance

Mitigating non-point source nitrogen in coastal estuaries is economically, environmentally, logistically, and socially challenging. On Cape Cod, Massachusetts, nitrogen management includes both traditional, centralized wastewater treatment and sewering as well as a number of alternative technologies. We conducted semi-structured interviews with 37 participants from governmental and non-governmental organizations as well as related industries to identify the barriers and opportunities for the use of alternative technologies to mitigate nitrogen pollution. The interviews were recorded, transcribed, and then analyzed using content analysis and rhetorical analysis. Cost and technical capacity to reduce nitrogen were the most discussed considerations. Beyond those, there were a slew of additional considerations that also impacted whether a technology would be installed, permitted, and socially accepted. These included: maintenance and monitoring logistics, comparisons to sewering, co-benefits, risk/uncertainty, community culture, extent of public engagement, permitting/regulatory challenges, and siting considerations. The insights about these additional considerations are valuable for transferring to other coastal areas managing nutrient impairments that may have not yet factored in these considerations when making decisions about how to meet water quality goals.     

Connectivity of Streams and Wetlands to Downstream Waters: An Integrated Systems Framework

Interest in connectivity has increased in the aquatic sciences, partly because of its relevance to the Clean Water Act. This paper has two objectives: (1) provide a framework to understand hydrological, chemical, and biological connectivity, focusing on how headwater streams and wetlands connect to and contribute to rivers; and (2) briefly review methods to quantify hydrological and chemical connectivity. Streams and wetlands affect river structure and function by altering material and biological fluxes to the river; this depends on two factors: (1) functions within streams and wetlands that affect material fluxes; and (2) connectivity (or isolation) from streams and wetlands to rivers that allows (or prevents) material transport between systems. Connectivity can be described in terms of frequency, magnitude, duration, timing, and rate of change. It results from physical characteristics of a system, e.g., climate, soils, geology, topography, and the spatial distribution of aquatic components. Biological connectivity is also affected by traits and behavior of the biota. Connectivity can be altered by human impacts, often in complex ways. Because of variability in these factors, connectivity is not constant but varies over time and space. Connectivity can be quantified with field‐based methods, modeling, and remote sensing. Further studies using these methods are needed to classify and quantify connectivity of aquatic ecosystems and to understand how impacts affect connectivity.     

Male tawny dragons use throat patterns to recognize rivals

The ability to distinguish between familiar and unfamiliar conspecifics is important for many animals, especially territorial species since it allows them to avoid unnecessary interactions with individuals that pose little threat. There are very few studies, however, that identify the proximate cues that facilitate such recognition in visual systems. Here, we show that in tawny dragons (Ctenophorus decresii), males can recognize familiar and unfamiliar conspecific males based on morphological features alone, without the aid of chemical or behavioural cues. We further show that it is the colour pattern of the throat patches (gular) that facilitates this recognition.     

Fish Assemblage Response to a Small Dam Removal in the Eightmile River System,Connecticut, USA

We examined the effects of the Zemko Dam removal on the Eightmile River system in Salem, Connecticut, USA. The objective of this research was to quantify spatiotemporal variation in fish community composition in response to small dam removal. We sampled fish abundance over a 6-year period (2005–2010) to quantify changes in fish assemblages prior to dam removal, during drawdown, and for three years following dam removal. Fish population dynamics were examined above the dam, below the dam, and at two reference sites by indicator species analysis, mixed models, non-metric multidimensional scaling, and analysis of similarity. We observed significant shifts in fish relative abundance over time in response to dam removal. Changes in fish species composition were variable, and they occurred within 1 year of drawdown. A complete shift from lentic to lotic fishes failed to occur within 3 years after the dam was removed. However, we did observe increases in fluvial and transition (i.e., pool head, pool tail, or run) specialist fishes both upstream and downstream from the former dam site. Our results demonstrate the importance of dam removal for restoring river connectivity for fish movement. While the long-term effects of dam removal remain uncertain, we conclude that dam removals can have positive benefits on fish assemblages by enhancing river connectivity and fluvial habitat availability.