Diversity in Mediterranean farm ponds: trade‐offs and synergies between irrigation modernisation and biodiversity conservation

Abstract

1. Agricultural intensification has caused dramatic biodiversity loss in many agricultural landscapes over the last century. Here, we investigated whether new types of farm ponds (made of artificial substrata) in intensive systems and natural-substratum ponds in traditional farming systems differ in their value for aquatic biodiversity conservation. 2. We analysed the main patterns of environmental variation, compared a-, b- and c-diversity of macroinvertebrates between ponds types and evaluated the role of submerged aquatic vegetation (SAV). Generalised additive models (GAM) were used to analyse the relationships of a- and b-diversity with environmental predictors, and variation partitioning to separate the effect of environmental and spatial characteristics on the variation in macroinvertebrate assemblages. Moran’s eigenvector maps (MEMs) were used to define spatial variables. 3. A principal coordinate analysis (PCoA) detected a primary environmental gradient that separated nutrient-rich ponds from those dominated by SAV; a secondary morphometric gradient distinguished natural-substratum ponds, with large surface area and structural complexity, from artificial-substratum ponds with steeper slopes. Natural-substratum ponds had almost twice the a- and c-diversity of artificial-substratum ponds, and diversity significantly increased when SAV was present, particularly in artificial-substratum ponds. Total phosphorus (TP) strongly contributed to explain the patterns in diversity, while SAV was a significant predictor of assemblage composition and diversity. GAMs revealed optima of both a-diversity at intermediate SAV covers and b-diversity at intermediate–high TP concentrations. 4. These findings have important implications for conservation planning. Adaptation of artificialsubstratum ponds by adding natural substratum and smoothing the gradient of pond margins would improve their conservation value. Development of SAV with occasional harvests and certain cautionary measures to control nutrient levels may also improve both the agronomical and environmental function of ponds

Ecological Drivers of Cladoceran Diversity in the Central European City (Łódź, Poland): Effects of Urbanisation and Size of the Waterbody

“…Emergent and submerged macrophytes have been well documented to support substantially higher macroinvertebrate diversity than other mesohabitats in ponds (Wilkinson, 1995;Water and San Giovanni, 2002;Gledhill et al, 2008;Bazzanti et al, 2010;Fuentes-Rodríguez et al, 2013;Goertzen and Suhling, 2013) which supports the findings in this study and provides further evidence to accept the second hypothesis;…”

“…Ponds in agricultural landscapes significantly contribute to regional biodiversity and can have high conservation value, often harbouring rare and endangered species (Søndergaard et al, 2005;Declerck et al, 2006;Fuentes-Rodríguez, 2013;Usio et al, 2013). Farm ponds in the Astarac region (SW France) supported a total of 52 macroinvertebrate taxa and made a greater contribution to the richness of Coleoptera, Odonata and Heteroptera than rivers in the study area (Céréghino et al, 2008a).…”

Disturbance from pond management obscures local and regional drivers of assemblages of primary producers

“…nitrogen and phosphorous) and the aqueous mineral content (e.g. conductivity and alkalinity), as previously detected in the same set of ponds for zooplankton (León et al ., ) and benthic macroinvertebrates (Fuentes‐Rodríguez et al ., ). Additionally, variables related to the nutrient content, such as Chl a and SAV coverage, were significant drivers of diversity for all the groups.…”

“…Most EMB are managed only extensively, this is because they are mainly used for stockbreeding purposes, and are situated in extensive agro‐silvo‐pastoral systems with low flushing by natural processes (evaporation, precipitation), and their water levels are controlled by water pumping. EMB average size and age are higher than for the other pond types (Fuentes‐Rodríguez et al ., ).…”

“…The influence of management practices on biodiversity has recently drawn the attention of conservationists, who attempt to understand the functioning of anthropogenically disturbed ecosystems (Lemmens et al ., ; Chester & Robson, ; Usio et al ., ). This is because the degree of manipulation and the management regime of ponds are both highly related to use and construction type (Casas et al ., ,b; Juan et al ., ; Bonachela et al ., ), with strong implication for their α‐, β‐ and γ‐diversities (Fuentes‐Rodríguez et al ., ).…”