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a) nMDS on 35 water beetle species from 32 ponds. Presence and absence of fish in ponds is indicated by black and grey circles respectively. b) Water beetle abundance, species richness, Shannon's index and Simpson's index in relation to fish presence/absence. c) Water beetle rarefaction curves for ponds with fish (black circles) and without fish (grey circles) and all ponds combined (white triangles).
Source publication
Traditionally, fish have been neglected in pond ecology and conservation studies and it has frequently been assumed that they have a detrimental impact on pond biodiversity and ecosystem function. In order to assess the consequences of fish for pond biodiversity and ecosystem structure we sampled a set of 40 small farmland ponds (20 with and 20 wit...
Contexts in source publication
Context 1
... of water beetle communities was not affected by fish presence/absence (ANOSIM, p > 0.05), as evident by the considerable scatter in the nMDS plot (Fig. 2a) and similar levels of community heterogeneity within each pond category (MVDISP = 0.65 and 0.61 for fish and non-fish ponds, respec- tively). In fact, variation in water beetle communities was largely driven by spatial variables (Table ...
Context 2
... alpha diversity and abundance were comparable between the two pond groups (Fig. 2b), Table 3. Results of variation partitioning using three models (environmental, spatial and fish presence/absence) and two models (environmental, spatial) for cladoceran, water beetle and macrophyte communities. Only the unique effect of each model is shown. E1: environmental model without biotic component, E2: environmental model ...
Context 3
... fish for cladoceran, water beetle and macrophyte communities in farmland ponds rarefaction curves highlighted that fish-containing ponds supported more speciose communities com- pared to fishless ponds. Notably, when data from all sites were combined, estimated species richness (i.e. gamma diversity) lied between that of the two pond categories (Fig. 2c). ...
Context 4
... water beetles, neither abundance, diversity nor community composition was affected by fish (Fig. 2a, b). However, other studies from shallow lakes and ponds have highlighted a negative effect of fish on water beetles in terms of both species diversity and abundance (Weir 1972;Fairchild et al. 2000). For ex- ample, Schilling et al. (2009) showed water beetles to be significantly less abundant and speciose in fish- containing USA lakes, ...
Citations
... Grey shading represents the 95% confidence interval. (Harper et al., 2021;Stefanoudis et al., 2017). However, it should also be noted that the visual, semi-quantitative methods used here to calculate fish intensity may not provide an accurate enough measure of the effect of fish and have contributed to the absence of association recorded in this study. ...
Garden ponds are a ubiquitous feature of urban landscapes and have the potential to be an important resource for biodiversity. However, the environmental and spatial factors influencing ecological communities within garden ponds have been poorly quantified to date, despite such evidence being critical to the development of effective management strategies that support biodiversity.
This study aims to identify the environmental and spatial factors influencing macroinvertebrate richness, abundance and compositional variation among garden ponds and provide management recommendations at the local and landscape scale. In total, 99 macroinvertebrate taxa were recorded from 30 garden ponds.
A negative association was recorded between ecological uniqueness (measured as the Local Contribution to Beta‐Diversity) and taxonomic richness among the garden ponds, and those ponds with high ecological uniqueness typically displayed high replacement (turnover) values. Surface area, total plant richness and non‐native plant richness were positively associated with macroinvertebrate richness. Taxonomic richness and abundance predominantly displayed a negative association with conductivity levels.
Current management practices for garden ponds are highly variable, often focussed on individual ponds. Based on the findings of this study, we recommend that management should focus on making garden pond surface areas as large as possible, ensure that there is a wide variety of native aquatic plant species present and manage conductivity levels. Garden ponds likely comprise a significant component of the urban freshwater network, and considering their management at both local and landscape scales will ensure that biotic communities inhabiting urban landscapes can be more effectively supported.
... In addition, ponds perform numerous functions like regulation of temperature and humidity. Despite their small size, ponds act as stepping stone that shows a range of benefits to the surrounding ecosystems (Berg et al., 2016;Stefanoudis et al., 2017). Thus, ponds need special consideration because of their ecological and social importance. ...
Ponds are self-sustaining and self-regulating ecosystems that are a vital part of the hydrological cycle and play a variety of roles in the biosphere. Ponds are diverse, extremely dynamic, and highly productive as they offer various services like harbor biodiversity, tool for combating water scarcity, have roles in pollution mitigation and carbon sequestration. Ponds also offer sustainable solutions to support climate change amelioration and aquatic resource management. However, ponds are the most neglected aquatic ecosystems, despite their huge ecological functions. Thus, ponds are debasing at an alarming rate as a result of increased anthropogenic activities and anthropogenically driven changes in natural processes, wreaking havoc on ecological health and water quality. In this context, the major threats to ponds include the dumping of solid waste, increased urbanization, pollution, encroachment and climate change which have resulted in the deterioration of ponds over the years. Sustainable management and restoration of ponds are crucial as this ecosystem offers a wide array of ecological functions. As a result, this research aims to assess the current state of ponds in India in terms of monitoring, ecological services provided, and the various threats to which they are subjected. Further, the discussions on management and perspective restoration strategies of this substantial ecosystem are also included. Thereby, this study suggests better conservation strategies for restoration, reclamation, and sustainable utilization of ponds.
... However, the impact of fish stocking can be negligible or even beneficial to invertebrate diversity, particularly at a regional scale, provided that fish species are carefully selected and managed (Gee et al., 1997;Hassall et al., 2011;Lemmens et al., 2013;Stefanoudis et al., 2017). ...
... Many Norfolk ponds have since been restored and stocked with crucian carp to realise this objective (Sayer et al., 2020), but maintaining populations and continued stocking requires justification in light of genetic evidence that indicates the crucian carp is not native to the UK (Jeffries et al., 2017). Nonetheless, there is support for UK conservation efforts to continue to protect the genetic integrity of the crucian carp at the European level, and provide a natural stronghold for the species (Harper, et al., 2019a;Jeffries et al., 2017;Stefanoudis et al., 2017) in the face of persistent declines throughout its native range of Northwest and Central Europe (Copp et al., 2008;Sayer et al., 2011Sayer et al., , 2020. ...
... The impact of stocking crucian carp on lentic biodiversity has been largely ignored, and little is known about its interactions with other pond species. Existing research suggests crucian carp are characteristic of ponds rich in invertebrates with extensive macrophyte cover (Copp et al., 2008;Sayer et al., 2011), and play an important ecological role (along with other pond-associated fishes) by increasing landscape-scale diversity across pond networks (Stefanoudis et al., 2017). Yet to our knowledge, only one study has assessed biodiversity (specifically macrophytes, zooplankton and water beetles) in ponds with and without pond-associated fishes in the UK (Stefanoudis et al., 2017), and no studies have specifically focused on crucian carp. ...
Fishes stocked for recreation and angling can damage freshwater habitats and negatively impact biodiversity. The pond‐associated crucian carp (Carassius carassius) is rare across Europe and stocked for conservation management in England, but impacts on pond biota are understudied. Freshwater invertebrates contribute substantially to aquatic biodiversity, encompassing many rare and endemic species, but their small size and high abundance complicates their assessment. Practitioners have employed sweep‐netting and kick‐sampling with microscopy (morphotaxonomy), but specimen size/quality and experience can bias identification. DNA and eDNA metabarcoding offer alternative means of invertebrate assessment. We compared invertebrate diversity in ponds (N = 18) with and without crucian carp using morphotaxonomic identification, DNA metabarcoding, and eDNA metabarcoding. Five 2‐L water samples and 3‐minute sweep‐net samples were collected at each pond. Inventories produced by morphotaxonomic identification of netted samples, DNA metabarcoding of bulk tissue samples, and eDNA metabarcoding of water samples were compared. Alpha diversity was greatest with DNA or eDNA metabarcoding, depending on whether standard or unbiased methods were considered. DNA metabarcoding reflected morphotaxonomic identification, whereas eDNA metabarcoding produced markedly different communities. These complementary tools should be combined for comprehensive invertebrate assessment. Crucian carp presence minimally reduced alpha diversity in ponds, but positively influenced beta diversity through taxon turnover (i.e. ponds with crucian carp contained different invertebrates to fishless ponds). Crucian carp presence contributes to landscape‐scale invertebrate diversity, supporting continued conservation management in England. Our results show that molecular tools can enhance freshwater invertebrate assessment and facilitate development of more accurate and ecologically effective pond management strategies.
... ). On the contrary, emerging evidence suggests that the presence of crucian carp, in some ponds, enhances landscape-scale diversity of aquatic plants and invertebrates(Harper, 2019; Harper et al., unpublished data;Stefanoudis et al., 2017). There are also habitat-related benefits associated with crucian carp conservation: for example, several species-poor highly terrestrialized, ponds restored as part of the NCP, showed substantial increases in macrophyte, invertebrate and amphibian species richness following restoration (compareFigures 2a and 2e; Sayer et al., 2013). ...
• The crucian carp Carassius carassius, a cyprinid fish characteristic of small ponds, is in decline throughout most of its European range, including in England where it is currently thought to be non‐native.
• The present study, undertaken by the Norfolk Crucian Project, reports on reductions in pond populations of crucian carp in Norfolk, eastern England as well as the success of recent introduction/re‐introduction efforts in terms of crucian survival, recruitment and growth over the last 10 years.
• A 72% decline in crucian carp distribution was observed between the 1950s–1980s and the 2010s. Of 18 crucian carp introductions/re‐introductions to restored and suitable existing ponds, 17 were successful in terms of survival, increasing the number of current crucian sites in Norfolk by 37%. Recruitment of young crucian carp was demonstrated for 12 of the 18 stocked ponds, with apparent elevated juvenile growth relative to other English and European populations.
• Delays in, or a lack of, crucian recruitment in some ponds appeared to result from the presence of other fish species (especially threespine stickleback Gasterosteus aculeatus) with predation and interspecific competition possible contributory factors.
• This study shows that, through combinations of pond rehabilitation and stocking, it has been possible to achieve a substantial recovery of crucian carp populations in the study region. Although the crucian carp is currently presumed to be non‐native within England, given other scientific studies that show a lack of adverse impacts of this species on native biota, and because it is greatly threatened in its native range, the call is sounded for more crucian carp conservation projects in other parts of England as well as in Europe more generally.
... Although we observed fewer detections from ponds for C. carassius than C. carpio, G. aculeatus, or E. lucius, previous research also indicates large and/or predatory fish are more detrimental to T. cristatus occurrence (Skei et al., 2006;Hartel et al., 2010;Chan, 2011). C. carassius does not hinder T. cristatus oviposition, larval behavior, or recruitment success (Chan, 2011;Jarvis, 2012), or pond invertebrate and macrophyte diversity (Stefanoudis et al., 2017). In contrast, C. carpio foraging reduces invertebrate density and macrophyte cover (Maceda-Veiga, López, & Green, 2017), which lowers T. cristatus reproductive and foraging success and heightens predator exposure (Rannap & Briggs, 2006;Gustafson et al., 2006;Chan, 2011). ...
Background
Environmental DNA (eDNA) metabarcoding is revolutionizing biodiversity monitoring, but has unrealized potential for ecological hypothesis generation and testing.
Aims
Here, we validate this potential in a large‐scale analysis of vertebrate community data generated by eDNA metabarcoding of 532 UK ponds.
Materials & Methods
We test biotic associations between the threatened great crested newt (Triturus cristatus) and other vertebrates as well as abiotic factors influencing T. cristatus detection at the pondscape. Furthermore, we test the status of T. cristatus as an umbrella species for pond conservation by assessing whether vertebrate species richness is greater in ponds with T. cristatus and higher T. cristatus Habitat Suitability Index (HSI) scores.
Results
Triturus cristatus detection was positively correlated with amphibian and waterfowl species richness. Specifically, T. cristatus was positively associated with smooth newt (Lissotriton vulgaris), common coot (Fulica atra), and common moorhen (Gallinula chloropus), but negatively associated with common toad (Bufo bufo). Triturus cristatus detection did not significantly decrease as fish species richness increased, but negative associations with common carp (Cyprinus carpio), three‐spined stickleback (Gasterosteus aculeatus), and ninespine stickleback (Pungitius pungitius) were identified. Triturus cristatus detection was negatively correlated with mammal species richness, and T. cristatus was negatively associated with gray squirrel (Sciurus carolinensis). Triturus cristatus detection was negatively correlated with larger pond area, presence of inflow, and higher percentage of shading, but positively correlated with HSI score, supporting its application to T. cristatus survey. Vertebrate species richness was significantly higher in T. cristatus ponds and broadly increased as T. cristatus HSI scores increased.
Discussion
We reaffirm reported associations (e.g., T. cristatus preference for smaller ponds) but also provide novel insights, including a negative effect of pond inflow on T. cristatus.
Conclusion
Our findings demonstrate the prospects of eDNA metabarcoding for ecological hypothesis generation and testing at landscape scale, and dramatic enhancement of freshwater conservation, management, monitoring, and research.
... The crucian carp (Carassius carassius; Figure 1) is an elusive, benthic fish species popular with anglers (Copp, Warrington, & Wesley, 2008;Sayer et al., 2011). As one of few fish associated with small ponds, this species may have an important ecological role but its relationship with other lentic biodiversity is understudied (Copp & Sayer, 2010;Stefanoudis et al., 2017). Although listed as 'Least Concern' on the International Union for Conservation of Nature Red List of Threatened Species, the species has declined throughout its native range of Northwest and Central Europe (Copp, Warrington, & Wesley, 2008;Sayer et al., 2011), with local extinctions across the UK (Copp & Sayer, 2010). ...
... Evidence suggests that the crucian carp is characteristic of small, plant-dominated, high-quality ponds (Copp, Warrington, & Wesley, 2008;Sayer et al., 2011;Stefanoudis et al., 2017), and English populations contain a substantial proportion of the overall genetic diversity for the species across Europe (Jeffries et al., 2016). English crucian carp populations may buffer species displacement by gibel carp at the European level (Jeffries et al., 2017), but are threatened by hybridisation with goldfish and possible displacement (Hänfling et al., 2005;Tarkan et al., 2009) as well as anthropogenic activity (Copp, Černý, & Kováč, 2008). ...
The crucian carp (Carassius carassius) is one of few fish species associated with small ponds in the UK. These populations contain genetic diversity not found in Europe and are important to conservation efforts for the species which has declined across its range in Europe. Detection and monitoring of extant crucian carp populations are crucial for conservation success. Environmental DNA (eDNA) analysis could be very useful in this respect as a rapid, cost‐efficient monitoring tool.
• We developed a species‐specific quantitative polymerase chain reaction (qPCR) assay for eDNA surveillance of crucian carp to enable non‐invasive, large‐scale distribution monitoring. We compared fyke netting and eDNA analysis at ponds with (n = 10) and without (n = 10) crucian carp for presence–absence detection. We examined biotic (crucian carp density represented by catch‐per‐unit‐effort [CPUE] estimate) and abiotic influences on eDNA detection probability using a hierarchical occupancy model, and eDNA quantification using a mixed‐effects model.
• eDNA analysis achieved 90% detection for crucian carp (n = 10), failing in only one pond where presence was known. CPUE estimate and conductivity had positive and negative influences on eDNA detection probability in qPCR replicates respectively. Similarly, conductivity had a negative effect on DNA copy number, whereas copy number increased with CPUE estimate.
• Our results demonstrate that eDNA analysis could enable detection of crucian carp populations in ponds and benefit ongoing conservation efforts, but imperfect species detection in relation to biotic and abiotic factors and eDNA workflow requires further investigation. Nonetheless, we have established an eDNA framework for the crucian carp as well as sources of imperfect detection which future investigations can build upon.
Metacommunity theory unites community and spatial ecology. Recent innovations in sequencing technology may now allow us, for the first time, to confront this theory with entire trophic community data at large scales. We metabarcoded vertebrate eDNA from 320 ponds in England. Using this "novel community data", we calculated the "internal structure" of this metacommunity, which is the contributions of environmental, biotic, and spatial processes, as well as stochasticity, to the distribution of each species and the composition of each site. Our results suggest that community assembly processes in this pondscape do not conform to a single metacommunity paradigm, but rather vary among species and over space. Combining this variation with external knowledge of species biologies allows us to better understand the differential influences of environmental filtering, species interactions, and dispersal limitation on several of the vertebrate species, paving the way for the routine empirical study of metacommunities.
Fishes stocked for recreation and angling can damage freshwater habitats and negatively impact biodiversity. The pond-associated crucian carp ( Carassius carassius ) is rare across its native European range and has been stocked for conservation management in England despite plausible non-native status. However, its impacts on English pond biota have not been broadly assessed. Freshwater invertebrates comprise a large proportion of aquatic biodiversity, encompassing many rare and endemic species, but small size and high abundance complicates their assessment. Practitioners have typically employed sweep-netting and kick-net sampling with microscopy, but specimen size/quality and experience can bias identification. DNA and eDNA metabarcoding now offer alternative means of invertebrate assessment. We compared invertebrate diversity in ponds (N = 18) with and without crucian carp using sweep-netting and microscopy, DNA metabarcoding, and eDNA metabarcoding. Five 2 L water samples and 4 minute sweep-net samples were collected at each pond. Inventories produced by morphotaxonomic identification of netted samples, DNA metabarcoding of bulk tissue samples, and eDNA metabarcoding of water samples were compared. Alpha diversity was greatest with DNA or eDNA metabarcoding, depending on whether methods were considered as standard or with potential biases removed. DNA metabarcoding reflected morphotaxonomic identification, whereas eDNA metabarcoding produced markedly different communities. Therefore, these complementary tools should be combined for comprehensive freshwater invertebrate assessment. Crucian carp presence minimally reduced alpha diversity in ponds, but positively influenced beta diversity through taxon turnover (i.e. ponds with crucian carp contained different invertebrate taxa to fishless ponds). Concerning pond invertebrates, the crucian carp can be considered a naturalised, non-impactful species in England, supporting continued conservation management in this region. Our results show that molecular tools can enhance freshwater invertebrate assessment and facilitate development of more accurate and ecologically effective pond management strategies.
Environmental DNA (eDNA) metabarcoding is revolutionising biodiversity monitoring, but has unrealised potential for ecological hypothesis testing. Here, we validate this potential in a large-scale analysis of vertebrate community data generated by eDNA metabarcoding of 532 UK ponds. We test biotic associations between the threatened great crested newt (Triturus cristatus) and other vertebrates as well as abiotic factors influencing T. cristatus occupancy at the pondscape. Furthermore, we test the status of T. cristatus as an umbrella species for pond conservation by assessing whether vertebrate species richness is greater in ponds with T. cristatus and higher T. cristatus Habitat Suitability Index (HSI) scores. T. cristatus occupancy was positively correlated with amphibian and waterfowl species richness. Specifically, T. cristatus was positively associated with smooth newt (Lissotriton vulgaris), common coot (Fulica atra), and common moorhen (Gallinula chloropus), but negatively associated with common toad (Bufo bufo). T. cristatus occupancy did not significantly decrease as fish species richness increased, but negative associations with common carp (Cyprinus carpio), three-spined stickleback (Gasterosteus aculeatus) and ninespine stickleback (Pungitius pungitius) were identified. T. cristatus occupancy was negatively correlated with mammal species richness, and T. cristatus was negatively associated with grey squirrel (Sciurus carolinensis). T. cristatus occupancy was negatively influenced by larger pond area, presence of inflow, and higher percentage of shading, but positively correlated with HSI score, supporting its application to T. cristatus survey. Vertebrate species richness was significantly higher in T. cristatus ponds and broadly increased as T. cristatus HSI scores increased. We reaffirm reported associations (e.g. T. cristatus preference for smaller ponds) but also provide novel insights, including a negative effect of pond inflow on T. cristatus. Our findings demonstrate the prospects of eDNA metabarcoding for ecological hypothesis testing at landscape scale and dramatic enhancement of freshwater conservation, management, monitoring and research.
The crucian carp ( Carassius carassius ) is one of few fish species associated with small ponds in the UK. These populations contain genetic diversity not found in Europe and are important to conservation efforts for the species, which has declined across its range. Detection and monitoring of extant crucian carp populations are crucial for conservation success. Environmental DNA (eDNA) analysis could be very useful in this respect as a rapid, cost-efficient monitoring tool. We developed a species-specific quantitative PCR (qPCR) assay for eDNA surveillance of crucian carp to enable non-invasive, large-scale distribution monitoring. We compared fyke netting and eDNA at ponds with (N = 10) and without (N = 10) crucian carp for presence-absence detection and relative abundance estimation, specifically whether DNA copy number reflected catch-per-unit-effort (CPUE) estimate. We examined biotic and abiotic influences on eDNA detection and quantification, and compared qPCR to standard PCR. Notably, eDNA occurrence and detection probabilities in relation to biotic and abiotic factors were estimated using a hierarchical occupancy model. eDNA analysis achieved 90% detection for crucian carp (N = 10), failing in only one pond where presence was known. We observed an overall positive trend between DNA copy number and CPUE estimate, but this was not significant. Macrophyte cover decreased the probability of eDNA occurrence at ponds, whereas CPUE and conductivity had positive and negative influences on eDNA detection probability in qPCR replicates respectively. Conductivity also had a negative effect on DNA copy number, but copy number increased with temperature and percentage of macrophyte cover. PCR was comparable to qPCR for species detection and may provide semi-quantitative information. Our results demonstrate that eDNA could enable detection of crucian carp populations in ponds and benefit ongoing conservation efforts, but imperfect species detection in relation to biotic and abiotic factors and eDNA workflow requires further investigation. Nonetheless, we have established an eDNA framework for crucian carp and sources of imperfect detection which future investigations can build upon.
