The application of palaeolimnology to evidence‐based lake management and conservation: examples from UK lakes

Abstract

ABSTRACT1. To help meet the requirements of water legislation, palaeolimnology has been widely used to establish 'reference conditions' and restoration targets for lakes. However, its potential for assessing the necessity and appropriateness of different lake management activities has been less publicized.2. With reference to selected case studies covering consultancy projects commissioned by UK conservation agencies, this study highlights the important applied role of palaeolimnology. Using varying combinations of diatom, plant macrofossil and cladoceran analysis, the degree, timing and in many cases the likely drivers of ecological change were inferred for several lake sites.3. From this basis advice was given on a range of lake management issues, including the need for sediment removal to combat eutrophication and/or the necessity of other nutrient reduction measures (Case study 1), the depth of sediment to be removed to maximize restoration potential through exposure of dormant banks of characean oospores (Case study 2), the requirement for fish management (Case study 3), and advice regarding fish farm expansion and licensing (Case study 4). Where possible management responses to the recommendations are outlined including any major outcomes.4. All case studies illustrate the advantages, for lake management and conservation decision-making, of placing current lake ecological conditions in the context of long-term change.

Improving the application of long‐term ecology in conservation and land management

“…Sayer et al . ). Based on the CE results, shared priorities might include thematic topics such as biodiversity (Willis et al .…”

“…For instance, by designing LTE to address site‐specific lake management questions set by managers, palaeolimnologists were able to evaluate proposed management activities and make practical recommendations to improve their conservation effectiveness (Sayer et al . ). This can result in multi‐use solutions, such as identifying species conservation strategies that also maintain recreational fishing values (Sayer et al .…”

“…This can result in multi‐use solutions, such as identifying species conservation strategies that also maintain recreational fishing values (Sayer et al . ) or allowing managers to maintain conservation values and public access, rather than considering costly mimicry of historic management systems (Waller ).…”

Sedimentary macrofossil records reveal ecological change in English lakes: implications for conservation

“…Notwithstanding the taphonomic issues associated with the plant-macrofossil relationship arising from the varying reproductive strategies and dispersal capabilities of plants, several comparative studies of macrofossil records with botanical records have shown plant macrofossils to reliably record shifts in the dominant aquatic vegetation of shallow lakes (Davidson et al 2005;Salgado et al 2010;Clarke et al 2014;Levi et al 2014). Plant macrofossils have been variously employed to investigate long-term successional changes in the submerged vegetation of lakes (Bradshaw et al 2005;Rasmussen and Anderson 2005), responses to recent eutrophication (McGowan et al 2005;Salgado et al 2010;Sayer et al 2010a;Madgwick et al 2011) and top-down impacts of fish (Sayer et al 2016), and to inform on lake conservation status and the need for appropriate management (Sayer et al 2012;Wiik et al 2014).…”

“…Consequently, a better understanding of historic plant communities and any ecological changes that may have occurred is important in setting objectives for a particular lake, especially where anthropogenic impacts may have resulted in changes to the character of a site where its 'natural' condition or reference condition is in question. With a few notable exceptions (Ayres et al 2008;Sayer et al 2012;Kowalewski et al 2013;Wiik et al 2014;Clarke and Lynch 2016), however, there have been few applications of plant macrofossil analysis to directly inform conservation and management. This contrasts with the numerous applied palaeolimnological studies that have defined chemical reference conditions for lakes using transfer functions to assist in management decisions (Dixit et al 1999;Hall and Smol 2010;.…”