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Biodiverity of Ponds and Pools

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Matthias Sprenger

on 3 May 2010

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Transcript of Biodiverity of Ponds and Pools

Content Ponds and Pools as model systems
Example: Does size matter?
Example: How to make ponds biodiverse?
The status of ponds in Europe Two reasons to pay attention to small scale ecosystems:
1. Their own specific characteristics and communities
2. Their role in metapopulation and community dynamics
and a third reason to cherish and preserve small scale ecosystems?
Abundant throughout the world
Variety of pond types
Variety of different anthropogenic stress
Delineated in landscapes
Small size of ponds and pools - easy to sample
Relatively simple communities
Simplicity of ponds The scientific value
of ponds and pools! Examples of progress in the knowledge of ecological theory and nature conservation issues gained by means of small aquatic model systems Local and regional influences on
community structure Variation in community structure
along a hydroperiod gradient What are the driving forces of community structure and diversity?

Local factors:
Abiotic environment (e.g. hydroperiod)
Biotic interactions (e.g. competition, predation)
Regional factors:
Influence the likelihood of individuals or species reaching the habitat
Large-scale environmental conditions (e.g. land-use) Pond community structure
Local variable hydroperiod explains community structure the best
Biotic control becoming more important with increasing level of permanence
Regional processes have minor importance
Colonization associated with chance events implies dispersal limitation
Connectedness has an impact - increasing local taxon richness
Hydroperiod as one of the key environmental gradient structuring communities in pond systems
--> "Race against the time" Some species cannot survive or reproduce in given time
--> Interfere organisms with long generation times
--> Exclude predatory species
--> Change pattern and strength of biotic interactions
For others it is an optimum along trade-offs between growth rate and competetive strength

Large ponds contribute the most to regional diversity
Non- permanent and ephermal pools harbour several species of conservation concern that do not occur in larger and more permanent ponds

--> Several types of ponds are necessary within a region to preserve genetic variation
1. Local and regional influences on community structure
2. Variation in community structure along a hydroperiod gradient Does size matter? The relationship between pond area and biodiversity ...so, some questions do occur. Do large ponds support higher species richness and how much of the variation in species number is explained by pond size?
Are the results the same if we first score the species according to their degree of rarity (conservation value)?
Do the taxonomic groups show the same or different trends?
Do species exhibit preferences for larger or smaller ponds?
Is a single large pond more favourable for biodiversity conservation than several small ponds (SLOSS)? Methods Study area
80 ponds scattered throughout Switzerland at altitudes between 210 - 2757 m a.s.l.
31 natural, 49 artificial
mean area: 8817 m²; mean depth: 1,66 m

Survey of flora and fauna
species richness of 6 taxonomic groups
(aquatic plants, aquatic Gastropoda, Sphaeriidae (Bivalvia), aquatic Coleoptera, adult Odonata and Amphibia)
standardised survey method during summer months over 4 years Conservation value of species assemblages
ranking according their degree of rarity in the national Red List
Conservation value per site of the species assemblage (C) = sum of the scores of all species present in the site
Mean conservation value per site (Csp) = C/number of species Results Species-area relationship SLOSS analysis Species response to pond size Relationship between
faunal and floral diversity Area and conservation value relationship Correlation between species richness and other environmental variables:
Altitude main factor
(accounting 57% of the variance faunal species richness)
Others like shade, shoreline development, connectivity or eutrophication less important
Correlation between species richness and pond area:
Significant for aquatic plants (7%), Gastropoda (7%) and Odonata (6%)
For the 60 low altitude ponds reaching 8%, 8% and 31%
Significance low --> many other factors influence relationship High conservation values in all sizes of ponds for aquatic plants, Gastropoda, Coleoptera, Amphibia and faunal groups pooled
Significant relationship with pond area only for Odonata
--> lack of correspondence between species richness and conservation value Set of ponds of small size has more species and higher conservation value than a single large pond of the same area
But large ponds (as like small) have a distinctive fauna Relation of the 64 most frequent species to pond size
1/5 show significant relationship to pond size
One Coleoptera for small ponds
11 species (2 aquatic plants, 2 Gastropoda and 7 Odonata) for large ponds
None of the 64 taxa show preference for medium sited ponds Species richness and conservation value is related to floral diversity for Gastropoda, Coleoptera, Odonata and the 4 faunal groups pooled - not for Amphibia Ponds and pools as model systems in conservation biology, ecology and evolutionary biology Ponds
like most small scale landscape elements - have been neglected
but contribute disproportional to regional diversity
feature extreme local environmental conditions - very specific biota
provide migration corridors and stepping stones Discussion Does a larger area support more species? It does for aquatic plants, for Odonata and to lesser extend for Gastropoda and total species richness
--> Different taxonomic groups can show different trends
Same positive relationships shown in other studies and for lakes
But it's a weak relationship compared to other species-area relationships
For terrestrial habitats stronger effects than for water
--> Weak relationship and not many significant relations
--> Area maybe only of secondary importance in determining pond diversity Does a larger area support a higher conservation value? Statistical relationship reduced after ranking of species
--> Even small ponds can contain important species groups for conservation
Low level of correspondence between species richness and conservation value demonstrates that richness not equal to conservation value Many small or a few large? A set of small sized ponds had more species and higher conservation value than one single large pond of the same total area
But large ponds cannot be ignored for nature conservation, since they harbour species missing in smaller ponds
Many species occur in both large and small ponds
--> Larger populations in larger ponds --> Less sensitive to extinction
On species level 1/5 show preference for larger ponds
Pond size prominent parameter only for selected taxa
A pond does not necessarily have to be large to have a high value
Need to promote the conservation of all ponds
Small ponds are easily created --> creation should be recommended How can we make new ponds biodiverse?
A case study monitored over 7 years Ponds support at least 2/3 of Britain's freshwater plant and animal species
Many new ponds are created in Britain every year (ca. 2000 in the lowlands alone)
But little is known of the ecological value
Execptionally little research into factors that drive new pond quality
Knowledge could be used to create highly biodiverse pond sites
--> tool for enhancing catchment biodiversity Methods Study area
Designed wetland (3.2 ha in total)
Surrounded by a river meander
Containing ca. 40 permanent (0.75 ha), semipermanent and seasonal (1-2 m²) pools; just 4 of them monitored
Ponds were allowed to colonise naturally

Survey methods
Water chemistry as background data (pH, conductivity, BOD, total oxidised nitrogen, ect.)
Pond area, depth, land-use, organic matter and sediment particle size, inflow velocity
Wetland macrophyte and aquatic macroinvertebrates lists were compiled in summer over 7 years
Wader and waterfowl data by log-books entries of birdwatcher

Analysis of biodiversity
Species richness: number of species or taxa
Species rarity: divided into "local" and "nationally scarce" Comparison with other data
National Pond Survey (in semi-natural landscapes UK)
Impact Pond Database (excluding semi-natural landscapes Engl.+Wales)
Lowland Pond Survey (only in lowland of UK)

Statistical analyses:
Differences in species richness and physico-chemical characteristics
Non-parametric methods (Mann-Whitney U, Kruskal-Wallis and Friedman tests)
Results Physico-chemical data Macroinvertebrate species Environmental data comparison Plant species Unshaded permanent pools between 0.75 and 0.02 ha in area
Mean water depth: 0.2 - 1.5 m
Calcium-rich ponds (mean pH of 7.9)
Low conductivity and low levels of P and N
Rapid colonisation by both marginal and aquatic plants
Within 6 month 34 species in the pool complex
And 9 - 19 species in monitoring ponds
Atfer 7 years 67 species in the pool complex
And 27 - 50 species in the monitoring ponds
4 early colonists disappeared again
But site still accumulates taxa 4 - 8 species after few month
After 3 years 46 - 57 species (mean 52)
And average invertebrate richness plateuxed
24 species of wader; 33 other wetland species
Seasonal pattern (majority present in spring and summer)
Wetland birds Comparison with other data
Wetland plants:
2-3 times more species than in the impaired ponds in the countryside
30% more species than in high-quality reference ponds
More species than recorded in any pond survey
Mirrored the richness of the plants
2 times more than impaired countryside ponds
1/3 more than the high-quality sites of the NPS
Wetland bird:
Waderdensity high and near optimum habitat
No differences in pH or calcium concentrations
Unusually unshaded and located in open semi-natural landscape
Higher proportion of wetlandds in their near vicinity
Signicficant lower conductivity From biogeographical theory we know the principle:
a larger area supports more species
--> attractive application in conservation biology
BUT more assumed than tested with ponds Discussion Pond richness Bottom-up effects produced by the physico-chemical environment:
Richness not explained by size, depth, substrate type or water source
Richness attributable to open shaded aspect, semi-natural grassland surrounds and/or low chemical conductivity
Stochastic processes influencing arrival of taxa
High proportion of wetlands in surrounding
Richness related to the proximity of other ponds ans wetlands
Site richness Possibility to use well-designed and targeted pond creation schemes for nature conservation
Best in areas where some wetland habitat already exist
Small pond complexes with semi-natural surrounds, good water quality and strong colonisation potential
Simple cost effective habitats to create
--> powerful ecological enhancement tool The ecology of European ponds: defining the characteristica of a neglected freshwater habitat Ponds
long time mostly ignored by freshwater biologists
managed and created by practitioners without scientific framework
are biosdiversity "hot spots"
provide ideal model for investigating metapopulation and metacommunity processes
How to master with ponds? European network of people and institutions involved in scientific issues and practical applications needed to protect ponds European Pond Conservation Network Understanding pond ecology (biodiversity, model system)
Values of ponds (biological indicators, ecosystem services)
Management of ponds (practical tools for conservation) Perspectives In Water Frame Directive ponds have not been well represented
Active research needed, to develop national strategies for pond conservation
Capacity for pond communities to respond to disturbance and global change
Results of research has to be communicated to managers to put into practice Pond colonisation New ponds:
can colonise quickly (plateau after 4 years macroinvertebrates, 6 years for macrophytes)
are more species rich and support more uncommen species than older one
have different physico-chemical environment (inorganic substrates, little vegetation cover, lack higher predators)
--> support aquatic invertebrates or plants not found at later stages of succession
have less nutrients --> greater potential to support diversity

Influenced by physical heterogenity and complexity
Different size, substrate, water source and hydrological regime
Range of hydroperiod contributes to richness Biodiversity of ponds Seminar talk by Matthias Sprenger 04.05.2010 ...and if I sparked your interest in island biogeography:

The Song of the Dodo:
Island Biogeography in an Age of Extinctions
by David Quammen

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