The consequences of paradigm change and poorly validated science: The example of the value of mangroves to fisheries

Abstract

Accuracy in representing, communicating and reporting science is critical to the translation of science into knowledge. Any lack of accuracy degrades the quality and reliability of consequent decisions. One common cause of inaccuracy is the use of superseded paradigmatic concepts with a lack of careful validation. This leads to evidentiary dissonance (an apparent abundance of evidence with little basis in actual reported scientific findings). We illustrate the nature and consequences of evidentiary dissonance using the example of estimates of the value of mangroves to fisheries, which are key motivators of decision‐making around land‐use activities in mangroves systems, mangrove restoration and disturbance offset initiatives. Causes include the use of inappropriate or inaccurate data and inadequate support for reasoning used to develop estimates of fisheries value. Evidentiary dissonance in linking estimates to scientific understanding has produced a citable and cited body of work with tenuous foundations in current ecological understanding, and a body of literature that is likely to lead to unrealistic expectations, misdirected and wasted resources, and perverse management outcomes.

Ecological Constraint Mapping: Understanding Outcome-Limiting Bottlenecks for Improved Environmental Decision-Making in Marine and Coastal Environments

“…Initially, identifying the Species Requirement Set will usually begin with a careful assessment of the body of knowledge already available on the species of interest. This needs to be an indepth evaluation to ensure the information is strongly evidence based and reflects the most up to date understanding (Sheaves et al, 2020a). A full assessment of the current state of knowledge will reveal what information is already available, and indicate what additional information may be required for the specific Constraint Mapping application.…”

“…Ecological Constraint Mapping provides a vehicle to facilitate a move from paradigm-based decision making, that risks reliance on poorly supported ideas (Sheaves et al, 2020a), to knowledgeinformed decision making. Without knowledge of the critical functional bottlenecks that constrain anticipated ecological outcomes, environmental decision-making will continue to provide sub-optimal, and sometimes perverse outcomes and result in wasted resources; an increasingly unsustainable situation in a world where ecosystems are increasingly impacted by anthropogenic activities and climate change (Waltham et al, 2020).…”

“…Although the blame for unrealised outcomes is often attributed to particular user groups (e.g., fishers or urban developers), the situation is rarely straightforward (Hawkins, 2011). In fact, the pervasiveness of these failings points to a significant overarching issue -that of unforeseen consequences -an issue often stemming from reliance on inappropriate knowledge (Sheaves, 2017;Sheaves et al, 2020a), a lack of whole-of-system understanding, or a paucity of appropriate knowledge of causal processes at appropriate spatial and temporal scales (Grubbs et al, 2016). This is exacerbated by the lack of a framework for conceptualising such knowledge and including it in environmental decision-making.…”

Brazilian mangroves at risk

“…The high productivity rates of mangrove ecosystems are crucial for the benthic and pelagic components of neritic food webs (Robertson et al 1992), providing direct and indirect resources (Tomlinson 1986, Luther & Greenberg 2009 for transient fishes and crustaceans as nursery and foraging habitats (El-Regal & Ibrahim 2014, Hutchison et al 2014, Sheaves 2017, Litvin et al 2018. In particular, mangrove ecosystems are critical for sustaining economically valuable crustaceans (e.g., pink shrimps and swimming crabs), finfishes (e.g., snooks, mullets, sardines, some catfish species, snappers, several sciaenids, and some groupers), and their fisheries (Robertson & Duke 1990, Sheridan 1992, Rogers & Mumby 2019, Sheaves et al 2020). In addition, mangrove forests provide several other ecosystem services, delivered to human society across local, regional and global extents (Barbier et al 2011).…”

Fishers’ Local Ecological Knowledge to Support Mangrove Research in the Galapagos

“…Although the importance of mangroves for fishery production has been globally acknowledged (Alongi, 2002;Lee et al, 2014;Whitfield, 2017;Sheaves et al, 2020), to date, most studies have focused on the mechanisms governing mangrove nursery function and the effects in adjacent fishery production (e.g., penaeid shrimps); with other benefits of the ecosystem receiving less attention (Manson et al, 2005;Carrasquilla-Henao and Juanes, 2017). Although global meta-analyses suggest a positive relationship between mangrove area and fish catch and yield (e.g., see Baran and Hambrey, 1999;Manson et al, 2005;Blaber, 2007;Aburto-Oropeza et al, 2008;Carrasquilla-Henao and Juanes, 2017), there is little evidence of this direct linkage at smaller scales.…”