Contributions of local knowledge to the physical limnology of Lake Como, Italy

Abstract

This article shows how local knowledge may be valuably integrated into a scientific approach in the study of large and complex hydrological systems where data collection at high resolution is a challenge. This claim is supported through a study of the hydrodynamics of a large lake where qualitative data collected from professional fishers was combined with theory to develop a hypothesis that was then verified by numerical modeling. First the fishermen's narratives were found to describe with accuracy internal wave motions that were evident in water column temperature records, which revealed their practical knowledge of the lake's hydrodynamics. Second, local knowledge accounts emphasized the recurrent formation of mesoscale gyres and return flows in certain zones of the lake in stratified conditions, which did not appear in the physical data because of limitations of sampling resolution. We hypothesized that these features developed predominantly because of the interaction of wind-driven internal motions with the lake's bathymetry, and the Earth's rotation in the widest areas of the basin. Numerical simulation results corroborated the fishers' descriptions of the flow paths and supported the hypothesis about their formation. We conclude that the collaboration between scientific and local knowledge groups, although an unusual approach for a physical discipline of the geosciences, is worth exploring in the pursuit of a more comprehensive understanding of complex geophysical systems such as large lakes.interdisciplinary science | internal waves | drift-net fishing | ethnographic interviewing | hydrodynamic modeling T he hydrodynamics of stratified lakes is highly relevant to ecosystem governance (1, 2) and also, in many lakes, to the practices of professional fishers. Whereas fundamental and applied limnologists collaborate to advance the field of physical limnology, the potential contribution of fishers' local practical knowledge has not been addressed.Local knowledge (LK) also known as traditional ecological knowledge and, in some cases, indigenous knowledge (3) arises from the way people live and work in their local environment; it is embedded in their long-standing practices, skills, traditions, and narratives, spanning across a broad range of temporal and spatial scales. Whereas a few decades ago most research on aquatic environments was conducted on field sites that were located near the researchers' university or research center, today the advances of telecommunication technologies and international scientific collaboration allow much environmental research to be conducted with limited time in the field (a comparative look at editions from the 1960s and the 2000s of a journal such as Limnology and Oceanography illustrates this point), limiting at the same time researchers' exposure to LK.In the last decade, however, there has been an increasing and explicit academic interest for LK in the science and governance of environmental systems, particularly in ecology (4-6). Despite a trend that has shown the potent...

Advancing the use of local ecological knowledge for assessing data‐poor species in coastal ecosystems

“…Integration of social and natural science methodologies has gained traction over the past decade, with an increased recognition that LEK and scientific knowledge can be complementary, together providing increased confidence in ecological information when there is agreement between the methods (Huntington et al 2004, Thornton andScheer 2012). Indeed, a growing number of case studies show concordance and corroboration between LEK and standard scientific data, including measurements of animal abundance and distribution (Anadon et al 2009, 2010, Azzurro et al 2011) and physical features of lake habitats (Laborde et al 2012). Quantifying variance in ecological data is standard practice in scientific surveys, yet assessment of variance in ecological information provided by resource users has received relatively little attention (Huntington et al 2004, but see Ainsworth 2011).…”

Fishers' knowledge identifies environmental changes and fish abundance trends in impounded tropical rivers

“…Furthermore, fishers' LEK does not always agree with biological surveys (Aswani and Hamilton 2004, Silvano and Begossi 2010, ), and fishers have been shown to possess limited knowledge on certain topics in some cases, such as regarding the spawning seasons and habitats of some fishes (Silvano et al 2006). Nevertheless, recent surveys based on structured and systematic research have demonstrated that fishers' LEK may be highly compatible with biological, fisheries, and even physical data (Silvano and Begossi 2005, , , Laborde et al 2012), therefore representing a useful, but often neglected, data source for fisheries management. Indeed, in some situations, fishers' LEK may be a unique available source of data, such as regarding fish migrations in large rivers (Valbo‐Jorgensen and Poulsen 2000) or along the coast (Silvano et al 2006), fish nursery sites (), and past abundance trends of exploited fish and invertebrates (Saenz‐Arroyo et al 2005, Salomon et al 2007, ).…”

“…In addition to its application in improving knowledge about specific organisms, the LEK of resource users can also be helpful for evaluating broader environmental changes over temporal scales ranging from years to decades. For example, LEK has been useful for evaluating the temporal patterns of fish abundance and associated ecosystem processes in the North Atlantic (Rochet et al 2008), changes in the vegetation composition and productivity of grazing fields (Fernandez-Gimenez 2000), fish kills linked to the hydrological cycle in a tropical wetland (Calheiros et al 2000), the hydrodynamics of an alpine lake (Laborde et al 2012) and the long-term impacts of changes in climatic conditions and ice cover for Arctic animals (Huntington 2011). However, although the potential of LEK is currently recognized, few studies have compared LEK and biological data from the same region and at the same spatial scale (Aswani and Hamilton 2004, Salomon et al 2007, Jones et al 2008, Rochet et al 2008, Silvano and Begossi 2010, Daw et al 2011, few of these comparative surveys have been conducted in freshwater ecosystems .…”

Local knowledge production, transmission, and the importance of village leaders in a network of Tibetan pastoralists coping with environmental change

“…The erosion of Tibetans' LEK, without replacement by the production of new knowledge suited to new circumstances, could reduce local capacity to cope with environmental changes and have cascading effects for ecosystem health and the provision of ecosystem services. Loss of LEK also represents a missed opportunity for pastoralists' knowledge to inform and improve regional climate adaptation policies and western scientific understandings of the ways in which this remote system is being affected by global change (Homann et al 2008, Reid et al 2009, Chaudhary and Bawa 2011, Fu et al 2012, Laborde et al 2012, Oba 2012, Smith and Sharp 2012). …”