Habitat Value Research Articles

Seasonal Patterns in Daily Flight Distance and Space Use by Great Egrets (Ardea alba)

In an effort to quantify the value of wetland habitats, GPS technology was used to document the movement patterns of 16 Great Egrets (Ardea alba) in North America. Patterns in daily flight distances and utilization distributions (UD; estimates of area occupied on the ground) were documented throughout the annual cycle. Maximum Daily Displacement (MDD), the farthest distance occupied by a bird from colony/roost (central place) in 24 hr was greatest (4.3 ± 0.1 km) during breeding season and lowest (3.3 ± 0.1) during post-breeding season. As birds visited multiple foraging sites and made multiple round trips to central places, this Total Daily Distance (TDD) was also measured. It increased from a mean of about 12 km during the incubation phase to about 35 km at the time of fledging. Average TDD was greatest during breeding season (14.2 ± 0.3 km) and lowest during winter (11.0 ± 0.2 km). The utilization distribution increased from 128 (± 21.3) ha during breeding season to 179 (±32.6) ha during winter. Birds that foraged at tidal sites used 183.3 (± 22.2) ha, twice as much area as birds that foraged strictly in freshwater sites (89.6 ± 21.3 ha).

Increasing water-use efficiency in rice fields threatens an endangered waterbird

Many species have adapted successfully to traditionally cultivated agricultural environments but, as production systems are intensified, this adaptation is reaching its limits. Conflicting facets of sustainability compound the problem. Here we describe how reductions in the use of water in rice fields is compromising the persistence of the largest known breeding population of the Australasian Bittern (Botaurus poiciloptilus), a globally endangered waterbird. In fields with traditional, early permanent water, bitterns began nesting around 77 days after inundation, with 65% of nests having sufficient time for all chicks to fledge before harvest. Our breeding success model showed that all nests could potentially be successful if permanent water was applied by early November, with a ponding period – the phase when fields are flooded – of at least 149 days. The modelling suggests that successful bittern breeding was unlikely where rice was grown using new water-saving methods – drill-sown and delayed permanent water – because the ponding period is too short. These methods have become the rice industry standard in Australia, rising from 34% of fields in 2014 to 91% in 2020. While this saved 1.5–4.5 megalitres/ha per year, it has undermined the habitat value of these agricultural wetlands. ‘Bittern-friendly’ rice growing incentives could encourage timely nesting and maximise breeding success. Early and sufficient ponding can be complemented by establishing adjacent wetland habitat refuges, maintaining grassy banks, and creating dedicated patches to fast-track nesting. Increasing water-use efficiency in agro-ecosystems is widely touted as being beneficial to the environment, but our research demonstrates the urgent need to manage trade-offs with biodiversity conservation.

Seagrass valuation from fish abundance, biomass and recreational catch

The value of critical habitats, such as seagrass, to act as a nursery varies spatially and temporally; however, such information is essential for the public and stakeholders to appropriately value and manage these habitats. We use an existing systematic long-term fisheries dataset in Port Phillip Bay to examine variability in nursery habitat value for an important commercial and recreational species, King George Whiting (Sillaginodes punctatus). Port Phillip Bay represents one of the most important marine assets in the southern hemisphere and is surrounded by the second-largest city in Australia, Melbourne, home to 4.5 million people. We modelled the abundance of King George whiting as a function of environmental variables, using Boosted Regression Trees (BRT). Fish densities ranged from 1,000 to 30,000 individuals ha−1y−1, equalling an adult biomass of 110–3,300 kg ha−1y−1. This production supports between 69 and 2,062 recreational fishing trips a year, with an estimated value of seagrass of AUD 687–20,625 ha−1y−1. Based on biomass production of King George Whiting and recreational fisheries data, the 6662 ha of seagrass in Port Phillip Bay are valued at around AUD 36 million annually.

Habitat use of Bechstein’s Bat (Myotis bechsteinii) and woodpeckers reveals the importance of old-growth features in European beech forests

Old-growth forests provide valuable habitats for bat and woodpecker species worldwide. However, the abundance of old-growth related habitat features is frequently reduced in managed forests. Bechstein’s Bat (Myotis bechsteinii, Kuhl 1817) is globally restricted to old-growth deciduous forests in Europe and therefore a species of high European conservation priority. Since the species prefers woodpecker cavities for roosting, woodpeckers are keystone species for Bechstein’s Bat. We surveyed woodpecker activity and forest structural features within 16 roost sites of Bechsteińs Bat and a random sample from the surrounding managed forest within the centre of the global distribution of Bechsteińs Bat. We found above-average quantity of old-growth related habitat features in the roost sites of Bechstein’s Bat. Five of six occurring woodpecker species revealed significantly higher densities in the roost sites of Bechstein’s Bat, demonstrating a distinct preference of the woodpeckers and the bat in managed forests for old, deciduous stands with high basal areas of large living trees (DBH > 50 cm), bearing deadwood structures and highest available tree cavity densities. Furthermore, when comparing the direct surroundings of roost trees to their wider surroundings (16 ha), cavity density and other old-growth features reached their maxima in the direct surroundings of roost trees (mean = 19.3 cavities ha−1), demonstrating a distinct habitat selection of Bechsteińs Bat for patches with maximum available cavity density on large and fine spatial scale. We found a close relation between the basal area of trees with limb break offs (>20 cm base diameter) and tree cavity density, which leads us to the conclusion that specifically injured but still vital, large trees play a major role for the development and long-term persistence of tree cavities. Finally, our analyses revealed a threshold of 20 (DBH > 50 cm) or 10 (DBH > 70 cm) large deciduous trees bearing deadwood structures per ha to fulfil the minimum habitat requirements of the woodpeckers and Bechstein’s Bat. Obviously, Bechsteińs Bat and the associated woodpeckers explicitly selected forest patches, which most closely resembled primeval forest benchmarks, emphasising the importance of maintaining and developing forest patches, providing the mentioned habitat features within managed forests.

Minor Treatments Can Play a Significant Role in Preserving Natural Habitats and Protected Species on the Shore of a Central European Lake

Semi-natural grasslands were previously established through traditional land use and maintained by active management, but their extension nowadays is declining rapidly, particularly in areas that also have tourism potential. In parallel, the conservation value of the remaining areas is increasing. The shore of Lake Balaton is a particularly good example, as Lake Balaton is an area highly affected by tourism, yet there have been valuable habitats able to survive and provide refuge for many vulnerable, protected species. Fortunately, we have reliable information about the vegetation of the area from two decades ago. Comparing these data with our recent surveys we investigated the changes in habitats and the distribution of protected plant species in connection with the active conservation treatments such as grazing or cutting. Our results show that in areas where treatments are still ongoing, protected plant species are more likely to survive, or even other species can appear, which is in clear contrast with conditions experienced in abandoned areas, where at least seven protected species have disappeared. According to our results, minor, but appropriately chosen and well-executed management interventions, can help in the long-term maintenance of species-rich habitats and improving the conservation status of threatened species.

Black Bears Select Large Woody Structures for Dens in Southeast Alaska

ABSTRACTTimber interests target coastal temperate rainforests, and within them stands composed of large trees potentially selected by American black bears (Ursus americanus) for denning. We identified the location of 75 black bear dens (used ≥14 days) in an intensively logged area on Prince of Wales Island, Alaska, USA. We ground‐visited a subset (n = 43) of these sites to measure the diameter of living trees and woody structures used by black bears for denning. We contrasted dens with random trees available in the study area in a series of models to characterize black bear den selection. All but 1 of 43 ground‐visited dens were located within woody structures, and all but 2 of these structures were >1 m diameter at breast height (dbh). We built resource selection functions (RSFs) to investigate black bear den selection across a range of spatial scales, though estimated selection was generally scale invariant. Black bears strongly selected large‐diameter woody structures (dead or alive) as dens at the home‐range scale, with the estimated relative strength of selection (RSS) for a 2‐m‐diameter tree approximately 166 times that of a 1‐m‐diameter tree. The estimated RSS of logged forest was unexpectedly greater (2.75 times) than that of the remaining commercially valuable old‐growth forest. Selection for den structures within stumps in previously logged stands suggests features of the woody structure may be of greater importance to black bears selecting dens than attributes of the surrounding forest. There was no observed correlation between bear den selection and second‐growth age, indicating that stumps may persist as suitable dens well after logging. Because denning is an important part of their life history and the denning structures used by black bears on Prince of Wales Island will eventually decay, retaining habitat value for bears in areas intensively managed for timber harvest requires strategies to recruit very large, old trees throughout the landscape. © 2021 The Wildlife Society.

Evidence‐based restoration of freshwater biodiversity after mining: Experience from Central European spoil heaps

Abstract Post‐mining freshwater habitats can serve as secondary habitats for threatened species. Being globally plentiful, their efficient restoration should be based on detailed evidence, especially under the current global decline of freshwater biodiversity. Synthetic studies focusing on the effects of restoration on freshwater communities are surprisingly rare, even for the most common restoration approaches. Such a lack of evidence limits the efficiency of habitat restoration in post‐mining landscapes. We combined a landscape‐scale field study of aquatic beetles and hemipterans in 29 freshwater pools at lignite spoil heaps in Czechia with a comparative synthesis of all 14 available datasets on freshwater communities at habitats created by coal mining in Central Europe. We compared the diversity and conservation value of freshwater habitats created by the main restoration approaches, including technical reclamation, spontaneous succession and their combination. Additionally, we analysed the detailed influence of key habitat descriptors on their conservation potential. Communities of aquatic beetles and hemipterans had more species in spontaneously and semi‐spontaneously developed pools, which were also preferred by more red‐listed species of both studied groups. The reviewed studies showed the same trend for amphibians, odonates, dipterans and macrozoobenthos, although some technically created pools and drainage ditches harboured some threatened species of aquatic plants, odonates and macrozoobenthos as well. Relatively independent of the restoration approach, the conservation value of freshwater communities was related to the particular characteristics of the restored habitats. The key beneficial features were as follows: smaller area of restored water bodies, heterogeneous littoral vegetation with suppressed dominants, heterogeneous bottom substrate with low and gradually sloping banks, absence of fish, sun‐exposed water surface and some forests in the surroundings. Synthesis and applications. Efficient restoration of freshwater habitats at post‐mining landscapes can create important secondary refuges for threatened and common species. Freshwater communities of high conservation value can be supported by all main restoration approaches if heterogeneous habitats are created. A combination of technical reclamation with spontaneous succession seems to be the most efficient approach to maximise biodiversity in freshwater habitats at coal‐mining spoil heaps.

An Insight into Antioxidant and Antimicrobial Activities of Ethnotherapeutically Important Trans Himalayan Medicinal Plants: A Review

The high altitude of the Himalayan cold desert represents a valuable habitat of natural resources. The extreme climatic condition manifested by intense mutagenic UV-radiation, physiological drought, desiccation and strong winds, makes the survival of plants really difficult. As a consequence of this atmospheric stressor, the plants produce unique metabolites which play a preventive role in intrinsic mechanism of sustenance. Many plant species of this region have been investigated in search of novel antioxidants and antimicrobials. Plants synthesize several antioxidants that aid in antioxidant defense system, thereby protecting plants against damage caused by active ROS. These compounds include chlorophyll derivatives, alkaloids, essential oils, phytosterols, phenolics and polyphenolics. Some of the antioxidants that have been isolated from plants include curcumin, quercetin, ascorbic acid, resveratrol amongst many other compounds. Additionally, the emergence of resistance to multiple antimicrobial agents has become a major threat to public health. Hence, fresh efforts towards new drug identification and development are greatly needed. Plants have long been used in traditional Indian medicine for numerous therapeutic benefits and low toxicity. Considering the growing interest in quest for search of plant based antimicrobials and antioxidants; an effort has been carried to systematically record the antioxidants and antimicrobial potential of plants of Himalayan region.

Benchmarking plant diversity of Palaearctic grasslands and other open habitats

AbstractAimsUnderstanding fine‐grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine‐grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups).LocationPalaearctic biogeographic realm.MethodsWe used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class.ResultsPatterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi‐natural) grasslands and natural grasslands are the richest vegetation type. The open‐access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats.ConclusionsThe GrassPlot Diversity Benchmarks provide high‐quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation‐plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology.

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Habitat value of bivalve shellfish and seaweed aquaculture for fish and invertebrates: Pathways, synthesis and next steps

AbstractAquaculture can have negative environmental impacts, adding to the suite of anthropogenic stressors that challenge coastal ecosystems. However, a growing body of scientific evidence indicates that the commercial cultivation of bivalve shellfish and seaweed can deliver valuable ecosystem goods and services, including provision of new habitats for fish and mobile invertebrate species. We completed a systematic literature review of studies focused on understanding habitat‐related interactions associated with bivalve and seaweed aquaculture, and a brief meta‐analysis of 65 studies to evaluate fish and mobile macroinvertebrate populations at farms and reference sites. Bivalve and seaweed aquaculture were associated with higher abundance (n = 59, range: 0.05× to 473×, median lnRR = 0.67) and species richness (n = 29, range: 0.68× to 4.3×, median lnRR = 0.13) of wild, mobile macrofauna. Suspended or elevated mussel and oyster culture yielded the largest increases in wild macrofaunal abundance and species richness. We describe the major mechanisms and pathways by which bivalve and seaweed aquaculture may positively influence the structure and function of faunal communities—including provision of structured habitat, provision of food resources and enhanced reproduction and recruitment—and identify the role of the species cultivated and cultivation gear in affecting habitat value. Given the continued deterioration of coastal habitats and increasing investments into their restoration, understanding how industry activities such as aquaculture can be designed to deliver food within ecological limits and have positive influences on ecosystem goods and services is essential in ensuring ecological, social and economic objectives can be achieved.

The conservation value of Aculeata communities in sand quarries changes during ecological succession

Sand quarries that are used occasionally and not subjected to rehabilitation are important biodiversity banks in both anthropogenic and semi-natural landscapes. However, their value for biodiversity preservation can change due to dynamic successional processes. We determined the responses of three Aculeata guilds: herbivores (Apiformes), predators (Crabronidae, Sphecidae), and parasitic species (Apiformes, Chrysididae, Crabronidae) to successional transformations in 32 sand quarries, along a successional chronosequence covering 15 years of spontaneous regeneration, classified into three stages (early, middle and late succession). Responses to succession differed depending on the trophic guild of the Aculeata. Values of community characteristics for herbivores and parasitic species were the highest in the middle stages of succession, whereas for predators, they did not change. The arrival of new species significantly affected the community structure of all three Aculeata guilds, although dominance structure did not change. However, only for predators, turnover was higher in the later successional stages. This was manifested by a rapid accumulation of new and rare species. In contrast, for parasitic species the species turnover decreased, and in the case of herbivores, it remained constant throughout the successional stages. Predators were also characterized by the highest number of species, present at all successional stages. We emphasize that the various patterns of species turnover can influence the conservation value of sand quarries assessed as numbers of rare and/or threatened species as well as other community characteristics and structure. The collected information will allow a more deliberate selection of protective measures to facilitate the preservation of these valuable habitats.

30-year changes of natural forests under human activities in the Indochina peninsula - case studies in Cambodia, Laos and Vietnam

Natural forests are a basic component of the earth's ecology. It is essential for biodiversity, hydrological cycle regulation, and environmental protection. Natural forests are gradually degraded and reduced due to timber logging, conversion to cropland, production forests, commodity trees, and infrastructure development. Decreasing natural forests results in loss of valuable habitats, land degradation, soil erosion, and imbalance of water cycle on the regional scale. Thus, operational monitoring of natural forest cover change has been in the interest of scientists for a long time. Current forest mapping methods using remotely sensed data provide limited capability to separate natural forests and planted forests. Natural forest statistics are often generated using official forestry national reports that have different bias levels due to different methodologies applied in different countries in forest inventory. Over the last couple of decades, natural forests have been over-exploited for various reasons. This led to forest cover degradation and water regulation capability, which results in extreme floods and drought of a watershed in general. This situation demands an urgent need to develop a fast, reliable, and automated method for mapping natural forests. In this study, by applying a new method for mapping natural forests by Landsat time series, the authors succeeded in mapping changes of natural forests of Cambodia, Laos, and Vietnam from 1989 to 2018. As a focused study area, three provinces: Ratanakiri of Cambodia, Attapeu of Laos, and Kon Tum of Vietnam were selected. The study reveals that after 30 years, 51.3% of natural forests in Ratanakiri, 27.8% of natural forests in Attapeu, and 50% of natural forests in Kon Tum were lost. Classification results were validated using high spatial resolution imagery of Google Earth. The overall accuracy of 99.3% for the year 2018 was achieved.

Attraction versus production in restoration: spatial and habitat effects of shellfish reefs for fish in coastal seascapes

Restored shellfish reefs provide valuable habitat for fish, but it is not clear how different approaches affect performance, and either promote the development of new fish populations (i.e. “production”) or simply attract individuals from the broader seascape (i.e. “attraction”). We measured the effects of a 1.5 ha shellfish reef restoration site on fish assemblages in Pumicestone Passage in eastern Australia, which contains replicates of six different restoration units: shell patch reefs, crates of shells, and biodegradable matrix, and each had replicates with and without live oysters. Fish were surveyed before restoration and then every 6 months for 30 months with baited (at restoration and control sites) and unbaited (at 106 sites across the seascape to detect potential fish attraction, and at the different restoration units) underwater cameras. Shellfish reef restoration represents an addition to the carrying capacity of Pumicestone Passage for fish for two key reasons. First, restoration significantly enhanced the diversity and abundance of fish assemblages and the density of harvestable fish at the restoration site by 3.8, 10.7, and 16.4 times, respectively. Second, fish distributions across the broader seascape did not change in response to succession at the restoration site. Fish assemblages did not differ between restoration units or the presence or absence of oysters. These findings further support the notion that restored shellfish reefs significantly enhance fish abundance and diversity and that restored reefs can enhance the overall carrying capacity of seascapes for fish, rather than simply centralizing them at restoration sites.

Fundamental dietary specialisation explains differential use of resources within a koala population.

The diets of individual animals within populations can differ, but few studies determine whether this is due to fundamental differences in preferences or capacities to eat specific foods, or to external influences such as dominance hierarchies or spatial variation in food availability. The distinction is important because different drivers of dietary specialisation are likely to have different impacts on the way in which animal populations respond to, for example, habitat modification. We used a captive feeding study to investigate the mechanisms driving individual dietary specialisation in a population of wild koalas (Phascolarctos cinereus) in which individuals predominantly ate either Eucalyptus viminalis or Eucalyptus obliqua foliage. All six koalas that primarily ate E. viminalis in the wild avoided eating E. obliqua for more than 1 month in captivity. In contrast, all seven koalas that primarily ate E. obliqua could be maintained exclusively on this species in captivity, although they ate less from individual trees with higher foliar concentrations of unsubstituted B-ring flavanones (UBFs). Our results show that fundamental differences between individual animals allow some to exploit food resources that are less suitable for others. This could reduce competition for food, increase habitat carrying capacity, and is also likely to buffer the population against extinction in the face of habitat modification. The occurrence of fundamental individual specialisation within animal populations could also affect the perceived conservation value of different habitats, translocation or reintroduction success, and population dynamics. It should therefore be further investigated in other mammalian herbivore species.

USE OF LANDSAT-8 OLI IMAGERY AND LOCAL INDIGENOUS KNOWLEDGE FOR EELGRASS MAPPING IN EEYOU ISTCHEE

Abstract. The eastern coastline of James Bay (Eeyou Istchee) is known to be home to beds of subarctic eelgrass (Zostera marina L.). These eelgrass beds provide valuable habitat and food source for coastal and marine animals and contribute valuable ecosystem services such as stabilization of the shoreline all along the coast. Despite reports from Cree communities that eelgrass bed health has declined, limited research has been performed to assess and map the spatial distribution of eelgrass within the bay. This study aims to address that issue by evaluating the capability of Landsat-8 Operational Land Imager (OLI) imagery to establish a baseline map of eelgrass distribution in 2019 in the relatively turbid waters of Eeyou Istchee. Three images acquired in September 2019 were merged and classified using Random Forests into the following classes: Eelgrass, Turbid Water, Highly Turbid Water, and Optically Deep Water. The resulting classified image was validated against 108 ground truth data that were obtained from both the eelgrass health and Hydro-Quebec research team. The resulting overall accuracy was 78.7%, indicating the potential of the Random Forests classifier to estimate baseline eelgrass coverage in James Bay using Landsat-8 imagery. This project is part of a Cree driven project, the Coastal Habitat Comprehensive Research Program (CHCRP). The CHCRP aims to combine Cree's traditional knowledge with Western science to better understand environmental changes in the coastal ecosystems and ecosystem services of eastern James Bay. The study is funded by a MITACS grant sponsored by Niskamoon Corporation, an indigenous non-profit organization.

What non-natural factors are behind the underuse of EU CAP funds in areas with valuable habitats?

While the European Union’s Common Agricultural Policy (EU CAP) is being redefined, natural habitats, treated as wasteland for many years, are becoming a crucial element in the promotion of environmentally-friendly management of farmland and the protection of biodiversity and the local cultural landscape. The aim of the study is to assess the effectiveness of the uptake of certain environmental CAP funds and to describe the factors behind the spatial differentiation of the uptake of these funds. Both natural and non-natural conditions are taken into account. The analysis is conducted for Poland, a country engaged in reform of the agricultural economy, which has sizeable areas of habitats of high value for nature and which represents a region of Europe in need of special public support for environmental improvement. The research procedure consisted of the following four main stages: (1) spatial delimitation of grasslands (taking into account their territorial rank and quality) and (2) the level of utilisation of funds under specific Agri-Environmental and Climate Schemes (AECSs), (3) determining the relationships – types and (4) identifying the causes of disproportions, taking into account selected non-natural conditions. Apart from indicator methods, use is made of spatial typology and spatial autocorrelation methods (global and local Moran I coefficients). The results of the analysis show the decisive influence of natural and environmental conditions on the amount of funds expended through AECSs. However, the study has also identified situations where non-natural factors come to the fore. Among the non-natural conditions, a key role is played by historical factors. The study has identified areas with untapped environmental potential and those where environmental farming measures are underutilised given the environmental potential of those areas. The situation described is detrimental to the effectiveness of support, which is contrary to CAP principles. The findings are important in the context of monitoring and evaluating the EU’s agricultural policies, which should take more account of the characteristics of the individual countries, including their natural regional and local specificities.

Spatial variation in the structure of overwintering, remnant Saccorhiza polyschides sporophytes and their associated assemblages

AbstractUnderstanding the structure and richness of natural communities is a fundamental goal of marine ecology, and foundation species such as large macroalgae have a disproportionate role in structuring biodiversity. However, high-resolution information on assemblages associated with macroalgae is lacking for many species and regions. Saccorhiza polyschides is a warm-temperate kelp with a relatively short lifespan (12–18 months), large thallus and bulbous holdfast offering habitat for diverse assemblages. In the UK, S. polyschides populations are thought to have proliferated recently. Here, we quantified the density and habitat structure provided by S. polyschides along a gradient of wave exposure within Plymouth Sound, and examined the composition and diversity of associated faunal assemblages. Density varied significantly between sites but not by wave exposure, while biometric measurements were generally highly variable. Senescing holdfasts from sporophytes offered valuable habitat, with high abundance and richness of associated assemblages, although these varied markedly between sporophytes and sites. Faunal abundance, taxon richness and diversity were significantly higher at fully exposed sites than at moderately exposed sites. Internal volume of holdfasts was positively correlated with faunal abundance and taxon richness. We recorded more than 27 distinct taxa and up to ~600 individuals within a single holdfast. Taxa included three fish species, including a novel observation of the pipefish Nerophis lumbriciformis. Further work is needed to examine seasonality in habitat structure and associated diversity patterns but our study demonstrates that even remnant holdfasts from decaying sporophytes represent a valuable microhabitat that may provide shelter, protection and food during winter.

Morphological Response of Channelized, Sinuous Gravel‐Bed Rivers to Sediment Replenishment

AbstractAnthropogenic alterations of sediment supply and transport processes may impact the ecological state of riverscapes and threaten infrastructure along the river. Sediment replenishment is one restoration method that is employed in channels impacted by sediment deficit. We performed flume experiments to investigate the channel bed response of a channelized, sinuous gravel‐bed river to periodic and episodic sediment replenishment. The grain size distribution of the replenished material, flow discharge, and sediment supply level were varied in long‐term steady‐state experiments. In addition, the channel routing of a single sediment pulse was investigated. The long‐term channel response included intensified sediment relocation and transversal bed leveling. Sediment supply level and flow discharge thereby exerted the strongest control over channel response, whereas the influence of the grain size distribution of the replenished material was minor. A simple habitat analysis using grayling as example species revealed that replenished sediment retained within the channel and thus providing episodically renewed clean gravel patches may increase spawning habitat availability. However, the general shortage of shallow habitats for grayling fry and juveniles in channelized rivers persisted regardless of sediment replenishment. Overall, the experiments illustrate that sediment replenishment may provide valuable habitats within a channelized river. Accompanying measures such as channel widening and the careful consideration of other remaining stressors are strongly recommended to increase restoration benefits further.

Uptake and accumulation of heavy metals by water body and Azolla filiculoides in the Anzali wetland

The Anzali international wetland is a valuable habitat to a wide variety of aquatic flora and fauna. This wetland ecosystem is being threatened due to various pollutants particularly the heavy metals discharging from different point and non-point sources. Concentration of various heavy metals (Cr, Pb, Hg, Cu, Zn, Cd, Ag and Ti) was examined in the water body and Azolla filiculoides (an exotic fern in the Anzali wetland). The samples regarding water and A. filiculoides were randomly carried out in three parts of the wetland (eastern, central and western parts) in May 2015. After preparing and digesting the samples, the concentration of the heavy metals was measured using ICP OES method. The obtained results showed that the concentration of Zn in water and A. filiculoides samples was higher than other heavy meals in all parts of the wetland (p < 0.05). Overall, concentration of the heavy metals was significantly higher in the eastern part of the wetland than other two sampling locations (p < 0.05). Also with comparing the concentration of the heavy metals in water and A. filiculoides, it was found that all examined metals (except Cd and Ag) in A. filiculoides had significantly higher concentration than water sample, while Cd and Ag in water and A. filiculoides did not have a significant difference with each other. Based on the results, it can be concluded that A. filiculoides can effectively absorb Cr, Pb, Zn, Hg, Cu, Cd, Ag and Ti so that it might be used as a valuable species for the bioremediation and the removal of heavy metals from the wetland.