Do restoration measures rehabilitate fauna diversity in raised bogs? A comparative study on aquatic macroinvertebrates

To assess whether raised bog restorationmeasures contribute to the conservation andrestoration of the fauna diversity,macroinvertebrate species assemblages werecompared between water bodies created byrewetting measures and water bodies whichhave not been subject to restorationmeasures, but are remnants offormer peat cuttings and trenches used forbuckwheat culture in the past.The restoration sites were inhabited bycharacteristic raised bog species and rarespecies, but their numbers were higher atthe remnant sites not affected byrestoration management. A considerablenumber of characteristic and rare faunaspecies were only found at the remnantsites. The remnant sites includedconsiderably more variation inmacroinvertebrate species assemblages andhad a higher cumulative species richness.The number of characteristicmacroinvertebrate species was not clearlyrelated to the presence of a characteristicraised bog vegetation. In restoration sitesnumbers of rare and characteristic speciesper site tended to increase with the timeelapsed after rewetting. However,restoration measures will not automaticallyresult in restoration of a more or lesscomplete macroinvertebrate speciesspectrum, as restoration measures have sofar resulted in habitats for only a limitednumber of the characteristic species.When planning restoration measures, it isrecommended to protect the populations ofrare and characteristic species present inthe area, as these populations may becomethe sources for colonization of rewettedsites. Safeguarding habitat diversityduring the restoration process andrestoration of different elements of thehabitat diversity of complete raised bogsystems will result in the characteristicfauna diversity being conserved andrestored more successfully.     

Differential Response of Aquatic Oligochaete Species to Increased Nutrient Availability – a Comparative Study between Estonian and Dutch Raised Bogs

To assess the effects of increased nutrient availability on aquatic oligochaetes in raised bogs, species assemblages were compared within and between fairly pristine raised bogs in Estonia and raised bog remnants in The Netherlands. Within the pristine bog landscape a distinct pattern in the species assemblage is present. In the most nutrient-poor water bodies, in the ombrotrophic raised bog, only the fragmenting, almost never mature, acid-tolerant species Cognettia sphagnetorum is present. In pristine Estonian raised bogs Nais variabilis, Lumbriculus variegatus and sexually reproducing species are limited to more minerotrophic water bodies, which have a higher decomposition rate of dead organic matter and, consequently, higher nutrient availability. With ten species the lagg zone is the most species-rich part of a pristine raised bog landscape. Most of these lagg zone species are not present in Dutch bog remnants as this part of the bog landscape has long been cultivated. Nais variabilis occurs in the Dutch bog remnants much more frequently than in Estonian bogs, whereas the frequency of C. sphagnetorum and L. variegatus is similar between both countries. These three species respond differently to the increased nutrient availability in The Netherlands, which could be linked to differences in their diets. In contrast to pristine bog pools, N. variabilis in Dutch raised bog remnants is present in water bodies not influenced by minerotrophic water. In Dutch raised bog remnants the occurrence of oligochaetes is not limited anymore by nutrient availability, due to the higher atmospheric nitrogen and sulphur loads in The Netherlands. Overall, it can be concluded that the degradation of Dutch raised bogs has resulted in the loss of both the nutrient-poor parts of the landscape and the special lagg conditions.     

Lentic macroinvertebrate assemblage structure along gradients in spatial heterogeneity, habitat size and water chemistry

Littoral zones of small water bodies are spatially heterogeneous habitats, harbouring diverse biotic communities. Despite this apparent heterogeneity, many studies have stressed the importance of water chemistry in determining the structure of littoral macroinvertebrate assemblages. The purpose of this study was to consider the relative importance of several spatial and water chemistry variables in explaining the patterns in the structure of macroinvertebrate assemblages in 21 lentic water bodies in northeastern Finland. Water bodies were selected to represent various habitat conditions ranging from small permanent bog ponds to small forest lakes. According to canonical correspondence analysis (CCA), the most important environmental factors related to assemblage composition were water body area, moss cover, total nitrogen and water hardness. In general, species composition in small bog ponds tended to differ from that in larger lakes with forested shoreline. Total species richness was best explained by a composite variable (PCA) describing physical habitat heterogeneity, species richness being lowest in small bog lakes with simple bottom structure and low amount of aquatic plants. Species numbers in dominant functional feeding groups were related to different environmental factors. Shredder species richness was best explained by a regression model incorporating total nitrogen and the amount of organic matter, both of which were negatively related to the number of shredder species. The number of gatherer species increased with mean substratum particle size. Scraper species richness was negatively affected by the abundance of detritus and positively affected by depth, and a model including both variables explained most of the variation. Variation in the number of predatory species was best explained by a regression model including moss cover and lake area.     

Loss of environmental heterogeneity and aquatic macroinvertebrate diversity following large-scale restoration management

Restoration management frequently focuses on recreating suitable environmental conditions for a ‘target vegetation’. This approach neglects the importance of habitat diversity and spatial configuration for individual species. Here, we investigate the role of environmental heterogeneity in a restoration context and report the response of aquatic macroinvertebrates to re-wetting measures, which were taken to mitigate desiccation in a bog landscape. Because only parts of the study area were affected by re-wetting measures, changes in aquatic macroinvertebrates could be compared between re-wetted and non-re-wetted parts. In addition, species were grouped into life-history strategies to test whether the invertebrate response differed between functional species groups. Total species numbers declined in the re-wetted parts and invertebrate assemblages became more similar both in terms of species and life-history strategies. These results indicate that large-scale re-wetting caused a functional homogenization. Changes in environmental conditions following re-wetting could be consistently related to changes in strategy composition. Retention of rainwater decreased the influence of groundwater. Here species increased that are adapted to physiological stress as well as those employing risk spreading, which indicates that environmental conditions had become harsher and less predictable. In contrast, reduced drainage locally increased groundwater influence, with life-history strategies indicating enhanced predictability of environmental conditions. Importantly, such conditions also characterise lagg zones and transitional mires in pristine raised bog landscapes, which are hotspots for biodiversity. Thus, while large-scale re-wetting decreased environmental heterogeneity, increasing the supply of groundwater seems a more promising restoration strategy for aquatic invertebrates in degraded peatlands.     

Conservation of bog plant species assemblages: Assessing the role of natural remnants in mined sites

Abstract. Bogs, economically valuable wetlands, are subjected to exploitation in southern Canada. We addressed plant conservation within bogs mined for peat, in which small undisturbed remnants are left, mostly at the margins of the mined areas. The main goal of the study was to test whether these remnants act as refuges for plants which could recolonize areas that are planned for restoration after mining is completed. Mosses, lichens and vascular plants were sampled in remnants of 24 mined bogs in southeastern Canada during the summer of 1997. The vegetation was also sampled at the margins and centres of 24 nearby natural bogs in plots similar in size to these remnants. Using similarity analysis and ordination techniques, we found that plant species assemblages in remnants of mined bogs differ from those near the margins of natural bogs, and that certain species are associated with the centre of natural bogs, due to the presence of pools. We also showed that water conditions of remnants are affected by drainage due to peat mining. Sphagnum moss showed itself to be a key indicator of mining effects on vegetation. Implications for peat resource management and bog conservation are discussed.     

Measuring the efficiency of fen restoration on carabid beetles and vascular plants: a case study from north‐eastern Germany

The aim of the study was to assess the effects of fen rewetting on carabid beetle and vascular plant assemblages within riverine fens along the river Peene in north‐eastern Germany. Drained (silage grassland), rewetted (restored formerly drained silage grassland), and near‐natural (fairly pristine) stands were compared. Eighty‐four beetle species (7,267 individuals) and 135 plant species were recorded. The richness of vascular plant species and the number of endangered species were highest on near‐natural fens. Fourteen years of rewetting did not increase plant species numbers compared with drained fens. For carabid beetles, however, species richness and the number of stenotopic species were highest on rewetted fens. Rewetting caused the replacement of generalist carabids by wetland specialists, but did not provide suitable habitat for specialist fen carabids or for plant species of oligo‐ or mesotrophic fen communities. Therefore, raising the water table on fens with nutrient‐rich, degraded peat was not sufficient for restoring species assemblages of intact fens, although water level was the most important environmental factor separating species assemblages. Our study illustrated that insects and plants may respond differentially to restoration, stressing the need to consider different taxa when assessing the efficiency of fen restoration. Furthermore, species assemblages of intact fens could not be restored within 14 years, highlighting the importance of conserving pristine habitat.     

Laggs can develop and be restored inside a raised bog

The lagg is an integral part of the hydrological system of a raised bog and can add significantly to the biological diversity of the ecosystem. Conservation and restoration of raised bogs should therefore involve this transition zone. The ideal situation for conservation is to protect or restore the natural lagg at the outside margin of the bog. However, it is not always possible to restore the lagg where it was historically situated. An analysis of historic maps of a raised bog in British Columbia, Canada, shows that in areas where the outflow of water from the bog has been impeded, lagg plant communities have naturally colonized parts of the bog that were historically open bog. This suggests that it is possible to create the ecohydrological conditions of a lagg in areas that are currently occupied by bog species. Based on this knowledge and the hydrochemical, hydrological, and vegetative characteristics of a regionally-specific lagg reference ecosystem, we describe several lagg restoration options for locations where it is not possible to restore the lagg at the outside margin of the bog.     

Moorland pools as refugia for endangered species characteristic of raised bog gradients

In intact raised bog landscapes transitions from ombrotrophic into minerotrophic conditions occur. These gradients are lost from many bogs due to peat harvesting and drainage, and are difficult to restore. To determine which endangered species are characteristic of pristine raised bog gradients and their current status in degraded bogs, plants and macroinvertebrates were surveyed in Estonian intact raised bogs and Dutch degraded bog remnants. Dutch national distribution data were used to determine whether communities with these species occurred outside bog habitats. Water chemistry data were used to describe associated environmental conditions. Intact bog gradients were the preferred habitat for six plant species and fifteen macroinvertebrate species, all of which are endangered. In degraded bogs these species were scarce or not recorded. In intact bogs these species lived at sites where runoff from the bog massif came into contact with regional ground water resulting in a gradient in pH, alkalinity, Ca, Fe and ionic ratio. Analysis of Dutch national distribution data revealed aggregations of these endangered species in moorland pools. These pools contained water chemistry gradients similar to those found in pristine bogs, which occurred at sites were groundwater seepage and stream water came in contact. In the past, stream water has been used to increase pH and trophic status of moorland pools facilitating fisheries. Today, this practice offers a conservation strategy for the protection of endangered species for which no short-term alternatives are available.     

Persistence and recolonisation determine success of bog restoration for aquatic invertebrates: a comment on Mazerolle et al. (2006)

1. Mazerolle et al. (2006) concluded that some aquatic invertebrate species, including bog‐associated species, readily colonise man‐made bog pools. In contrast, in Dutch bog remnants Van Duinen et al. (2003) found that a considerable number of bog‐associated species do not colonise newly created bog pools. 2. The conclusion of Mazerolle et al. (2006) is based on vagile aquatic invertebrates. Here, we question whether their conclusion can be extended to more sedentary species, which were not captured in the Canadian study, but made up an important part of the invertebrate assemblage in the Dutch study. This discrepancy could be caused by sampling artefacts, low colonisation rates of these species or an incomplete restoration of site conditions. 3. In Canada, chances of recolonisation may be higher than in the Netherlands, as natural and near‐natural bogs are more extensive. In the Netherlands, with low chances of recolonisation, persistence of species may be more important. To disentangle the relative importance of persistence and recolonisation, evaluations of the success of restoration projects need to cover the entire invertebrate assemblage, including both vagile and more sedentary species.     

Aquatic microinvertebrate abundance and species diversity in peat bogs of Tierra del Fuego (Argentina)

Peat bogs are regarded as extreme environments due to their low pH and low nutrient concentration, and thus hold a unique biota adapted to these particular conditions. The island of Tierra del Fuego encompasses the southernmost extensive peat bog area in the world, and is therefore particularly interesting from a biogeographical viewpoint. Within the same peat bog, different environment types can be identified: clear ponds, vegetated ponds and Sphagnum patches. In this study we compare the abundance, richness and species diversity of microinvertebrates (Copepoda, Cladocera and Rotifera) in these three types of environments from two peat bogs (Andorra and Rancho Hambre). Out of the 29 taxa recorded, 19 were common to both peat bogs, including four cladocerans endemic to Southern Patagonia and three rotifers endemic to Fuegian peat bogs. The rotifers were the dominant group in all environment types from Rancho Hambre, while in Andorra the Sphagnum moss was dominated by copepods, particularly harpacticoids. The results revealed that the environment type rather than peat bog was the key factor at explaining differences in species richness and diversity among microinvertebrate communities. This study highlights the importance of Sphagnum moss as a low diversity extreme environment which supports highly endemic species.     

Linking ecological function to species composition in ecological restoration: Seed removal by ants in recreated woodland

Evaluations of ecological restoration typically focus on associating measures of structural properties of ecosystems (e.g. species diversity) with time since restoration efforts commenced. Such studies often conclude a failure to achieve restoration goals without examining functional performance of the organism assemblages in question. We compared diversity and composition of ant assemblages and the rates of seed removal by ants in pastures, 4‐ to 10‐year old revegetated areas and remnants of Cumberland Plain Woodland, and an endangered ecological community in Sydney, Australia. Ant assemblages of forest remnant sites had significantly higher species richness, significantly different species composition and a more complex functional group structure in comparison with ant assemblages of pasture and revegetated sites, which did not differ significantly. However, the rates of seed removal by ants in revegetated sites were similar to those in forest remnants, with the rates in pasture sites being significantly lower. Approximately, one‐third of all ant species were observed to remove seeds. Forest remnant sites had significantly different assemblages of seed removing ant species from those in pasture and revegetated sites. These results demonstrate that similar ant assemblages of unrestored and restored areas can function differently, depending on habitat context. Evaluation of restoration success by quantifying ecosystem structure and function offers more insights into ecosystem recovery than reliance on structural data alone.     

Is rewetting enough to recover Sphagnum and associated peat-accumulating species in traditionally exploited bogs?

When restoring ecosystems, the simple removal of stresses causing degradation may seem preferable over other more costly and time consuming approaches. However, some restoration techniques can be implemented at reasonable cost and with increased efficiency in certain cases. We examined the successional trajectories of vegetation within abandoned block-cut peatlands in a major peat-producing region of Eastern Canada to evaluate whether the use of rewetting as a restoration technique can assist in the recovery of a typical bog plant community dominated by Sphagnum compared to spontaneous recolonization alone. We surveyed a total of 55 trenches in 6 peatlands twice, ~25 and ~35 years after the cessation of peat extraction. Canonical ordinations evidenced a generalized process of afforestation during the decade studied, partially driven by agricultural drainage in the surrounding landscape. Plant communities were dominated by ericaceous shrubs that hampered the spontaneous recovery of a Sphagnum-dominated system typical of bogs in the short and medium-term. Three of the six peatlands surveyed were partially restored by blocking drainage ditches. There, we surveyed plant composition in rewetted (28) and non-rewetted (26) trenches and observed that rewetting mitigated the increase in tree dominance, decreased the dominance by ericaceous shrubs, and favored the spread of non-vascular species with a wet habitat preference (notably Sphagnum species from the Cuspidata section). We conclude that the use of low intervention restoration techniques in block-cut bogs, such as the blockage of former drainage ditches, can re-orient undesired vegetation trajectories driven by spontaneous recolonization alone.     

Animal Colonization of Restored Peatlands: Inoculation of Plant Material as a Source of Insects

Ecological restoration of mined peatlands in North America involves active reintroduction of bog plant species. Animals are not actively reintroduced, thus the re‐establishment of peatland fauna must occur either by inoculation along with introduced plant material or by dispersal. We examined the extent to which insects are reintroduced to restored sites with plant material by rearing insects from shredded vegetation collected in three donor sites. We assessed differences in abundance, diversity, and composition of taxonomic and trophic groups among seasons and sites. Abundance and species richness did not differ by season, but species assemblages did. The three sites were significantly different in abundance, but not in species richness and assemblages. Few insects emerged from the vegetation, suggesting that shredded plant material may not be the primary source of insect colonists. Insects likely recolonize by active or passive dispersal from the surrounding area. The species pool was similar among donor sites; consequently a mined site could be inoculated with vegetation from another peatland in the same region and this would not affect the insect assemblages at the initial stage of establishment. Diapause may be a major factor for emergence success among seasons of collection. Knowledge of how restoration techniques influence establishment of insect communities will help predict longer‐term outcomes of restoration on biotic communities in peatlands.     

Mechanisms involved in the re-establishment of Sphagnum-dominated vegetation in rewetted bog remnants

Restoration of peat bog vegetation inhighly degraded peatlands is generallyattempted by improving the hydrology ofthese areas. The present paper discussesand explains various restoration strategiesrelating to peat quality, water chemistryand hydrology. In some cases, (shallow)inundation of bog remnants leads to a rapidredevelopment of (floating) Sphagnumvegetation, usually when poorly humifiedSphagnum peat is still present. Afterinundation, the peat either swells up tothe newly created water table or becomesbuoyant, in both cases creating a favorablesubstrate for Sphagnum mosses. Bulkdensity and methane production rate play animportant role in the buoyancy of floatingpeat, methane providing buoyancy to thesubstrates. The presence of (slightly)calcareous groundwater in the peat base mayenhance the development of floating raftsby stimulating decomposition processes.Alternatively, the growth of submerged Sphagnum species can also lead to thedevelopment of floating rafts. This dependson the penetration of light into the waterlayer and the availability of carbondioxide in the water layer.Many bog remnants, however, only havestrongly humified peat, which does notfavor the redevelopment of Sphagnumcarpets after deep inundation. On the otherhand, most peat moss species appear to dovery well on surface soaked black peat,which is why shallow inundation (< 0.3 m)is to be preferred in such cases.Compartmentalization of the terrain willprobably be necessary to ensure a more orless constant water table.An important prerequisite for thesuccessful restoration of bog remnants isthe development of a hydrologicallyself-regulating acrotelm. Key speciesinvolved in this development are Sphagnum magellanicum, Sphagnumpapillosum and Sphagnum rubellum.These typical hummock and lawn species areusually very slow colonizers compared tohollow species such as Sphagnumcuspidatum and Sphagnum fallax.Introduction of key species in carpetsdominated by hollow species or on baresubstrates appears to be very successful,indicating that the main constraint iscolonization.     

Odonate species occupancy frequency distribution and abundance–occupancy relationship patterns in temporal and permanent water bodies in a subtropical area

This paper investigates species richness and species occupancy frequency distributions (SOFD) as well as patterns of abundance–occupancy relationship (SAOR) in Odonata (dragonflies and damselflies) in a subtropical area. A total of 82 species and 1983 individuals were noted from 73 permanent and temporal water bodies (lakes and ponds) in the Pampa biome in southern Brazil. Odonate species occupancy ranged from 1 to 54. There were few widely distributed generalist species and several specialist species with a restricted distribution. About 70% of the species occurred in <10% of the water bodies, yielding a surprisingly high number of rare species, often making up the majority of the communities. No difference in species richness was found between temporal and permanent water bodies. Both temporal and permanent water bodies had odonate assemblages that fitted best with the unimodal satellite SOFD pattern. It seems that unimodal satellite SOFD pattern frequently occurred in the aquatic habitats. The SAOR pattern was positive and did not differ between permanent and temporal water bodies. Our results are consistent with a niche‐based model rather than a metapopulation dynamic model.     

Are butterflies and moths useful indicators for restoration monitoring? A pilot study in Sydney's Cumberland Plain Woodland

Summary   Moths and butterflies are strongly associated with vegetation structure and composition, which makes them a suitable indicator taxon for various ecological studies. Despite a good knowledge of many Australian lepidopteran taxa, they have rarely been used for restoration assessment. To explore the feasibility of using Lepidoptera as an indicator taxon for restoration monitoring in Australia, we used it to evaluate the success of a large-scale revegetation program in western Sydney. We compared moth and butterfly assemblages sampled with relatively low intensity in unrestored pastures, revegetated pastures and remnants of endangered Cumberland Plain Woodland (restoration aim). A light-trap survey of moth assemblages showed no significant differences in moth species richness and composition between any of the treatments with traps in revegetated areas producing most species rich samples. Butterfly surveys conducted over a 1-year period showed a considerable increase in butterfly species richness in revegetated areas compared to pastures, while forest remnants still had twice as many butterfly species compared to revegetated areas. Current revegetation practices employed to restore Cumberland Plain Woodland increased the diversity of lepidopteran assemblages, however, it is not clear whether they are on a trajectory towards the reference assemblages of forest remnants. Our study demonstrates that Lepidoptera, particularly butterflies, has a potential for broader application as an indicator group in restoration monitoring in Australia.     

Effects of a hydrological protection zone on the restoration of a raised bog: a case study from Northeast-Germany 1997–2008

We investigated the changes of water level and vegetation in a restored cut-over raised bog in response to a hydrological protection zone established around the bog. The restoration began 1997 and techniques involved ditch blocking within and around the bog to stimulate a return to conditions of intact bog ecosystems. In order to monitor the rehabilitation of the raised bog, water levels and vegetation have been recorded since before restoration measures began. The monitoring is ongoing, but an assessment of 15 year’s data (1994–2008) is presented. A hydrological protection zone with continuous high water levels could be established around the raised bog which minimizes the runoff of precipitation. Shortly after the first measures, the water levels increased significantly at all dipwells. Parallel to the increasing water levels a vascular plant species assemblage and a diverse Sphagnum community developed. In particular Sphagnum fimbriatum, S. palustre, S. recurvum and S. squarrosum spread efficiently. The cover of trees decreased significantly because of high water levels and ongoing acidification by Sphagnum spp. The high water levels have stimulated the re-vegetation and the hydrology self-regulation of the acrotelm. The successful regeneration of the acrotelm particularly became apparent in years with below-average precipitations (e.g. 2008), when the water levels in the central parts of the raised bog did not fall back to the low level reached in previous years, which had also remarkably water deficits (e.g. 2003).     

Flood‐Pulse Effects on Zooplankton Assemblages in a River‐Floodplain System (Gemenc Floodplain of the Danube,Hungary)

We studied the structure and population dynamics of zooplankton assemblages in the water bodies (eu‐, para‐, plesiopotamal and conjunctive water bodies) of a temperate floodplain during flood events. Here we report differences in the species composition of these water bodies in the two stages of flood pulses: rising vs. receding. During the receding period the proportion of larger and tychoplanktonic species increased. Similarity among zooplankton assemblages of these floodplain water bodies increased during the rising and decreased during the receding period. Species richness, diversity and population density values of zooplankton assemblages increased during the receding period in all types of water bodies except the eupotamal. The guild ratio of rotifer assemblages showed characteristic, but somewhat ambiguous changes. We conclude that the hydrological regime affects the structure and dynamics of zooplankton assemblages on the floodplain. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Natural peat bog remnants promote distinct spider assemblages and habitat specific traits

Peat bogs are very sensitive and highly endangered ecosystems. They were once typical landscape elements in northern Germany, but today only a few remnants exist. On-going habitat degradation has alarming adverse effects on biodiversity, and, from a conservation viewpoint, it is imperative to evaluate the current ecological quality of the remaining peat bog remnants to assess the intensity of degradation and to suggest reasonable management strategies. In 2007, spiders were sampled in 23 study sites representing typical peat bog habitat types in the northern parts of Westphalia (NW Germany). In all, 214 species from 18,413 adult individuals have been collected. Multivariate analyses showed that different peat bog successional stages harbour distinct spider assemblages with succession being the main driver for species separation. Pardosa sphagnicola, Pirata piscatorius and P. uliginosus can be considered as flagship species for near-natural or natural peat bogs. Trait analyses showed that habitat specialisation for high moisture is negatively affected by succession. Peat bogs are now only small remnants, but, nevertheless, they have a high conservation value as they still harbour a distinct species assemblage and specialised species.     

If we build – they mostly come: partial functional recovery but persistent compositional differences in wetland beetle community restoration

There is growing evidence of restoration success for wetland plant communities. However, little research has been done on the associated invertebrate community. We test whether restoring plant communities after peat extraction is sufficient for restoring the taxonomic and functional composition of beetle communities. We monitored taxonomic and trait‐based community metrics for beetle assemblages on restoration islands that were up to 13 years old and compared these with the adjacent “target” undisturbed peat bog. Recovery of beetle abundance, species richness, and trophic structure on the islands was remarkably rapid (i.e. within a decade) and converged on that of the undisturbed peat bog within 13 years after restoration commenced. In contrast, small, native, and poor‐dispersing taxa were persistently less abundant on the islands than in the undisturbed peat bog, causing persistent differences in species composition, even on the oldest islands. These poor‐dispersers probably need assistance to reach the islands and possibly ongoing intervention to allow them to survive there. Our findings emphasize the potential for functional trait analysis to reveal barriers to full restoration of insect community composition.