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1

Ecology of testate amoebae (Protists) in a Sphagnum-dominated peat bog and the relationship between species assemblages and environmental parameters

Niedźwiecki M., Mieczan T., Adamczuk M.

Oceanological and Hydrobiological Studies

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2016

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Vol. 45, No. 3

344--352

EN

Despite its ecological importance, little information is available regarding spatial and seasonal changes in the testate amoebae community in peat bogs. The objectives of this study were to examine the structure of communities and horizontal distribution of testate amoebae fauna, to improve the understanding of factors affecting the distribution of moss testate amoebae communities and to analyze the seasonal changes in testate amoebae communities in a Sphagnum-dominated peat bog (eastern Poland). A total of 45 testate amoebae species were identified in the samples. The highest species richness occurred in hollows dominated by Sphagnum angustifolium, much lower numbers of taxa were observed in hummocks dominated by Sphagnum magellanicum and Polytrichum. The Monte Carlo permutation test showed the significance of Ntot, temperature, pH, and the depth to the water table for the variability of testate amoebae in all microhabitats. Species found in spring samples were associated with the increased Ntot content. Species occurring in summer samples were associated with the increasing pH gradient and species developing in late spring and autumn preferred a greater depth to the water table.

2

Differentiation of microbial loop components in small anthropogenic reservoirs

Mieczan T.

Polish Journal of Ecology

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2014

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Vol. 62, nr 2

323--334

EN

The interactions between bacteria and heterotrophic protists are essential for the ecosystem ecology of freshwater. The basic objective of the study was to analyse the seasonal dynamics of changes in particular elements of the microbial loop (bacteria, flagellates and ciliates) in various types of small water bodies. The classification into particular trophic groups of ciliates and the role of the organisms in the functioning of the microbial loop was also analysed. The abundance and biomass of microbial communities has been assessed in eight reservoirs of varied origin (peat pits, clay pits and post-mining reservoirs), in order to test a hypothesis that the microbial communities differed among reservoirs and that differences could be related to fertility of habitats. Fieldwork was done from April to November 2010-2012. From each reservoirs once a month, three samples were collected with a 5-litre planktonic sampler. Samples were taken on two stations: pelagic – located in the deepest part of each reservoirs and littoral. The density and biomass of bacteria and protists significantly differed between the studied reservoirs, with the lowest numbers in the peat pits and clay pits and the highest in the post-mining reservoirs. All of the studied reservoirs were generally dominated by ciliates belonging to the orders Oligotrichida and Scuticociliatida constituted > 30% of the total numbers. In all reservoirs bacterivorous ciliates occurred in the highest numbers, while predators ones in the lowest. Generally, concentrations of nutrients (especially total phosphorus) is not a factor having the strongest effect on the abundance of bacteria and heterotrophic flagellates and the number and strength of correlations between microbial loop components. The relations demonstrated between bacteria and protists point to an important process of matter and energy flow from bacteria to higher trophic levels. In peat pits, relations between bacteria and ciliates were stronger. Only in clay pits and postmining reservoirs the correlation between bacteria and heterotrophic flagellates were found. Consuming much of bacterial productions, protozoa become an important link between bacteria and micrometazoans.

3

Vertical micro-distribution of psammonic ciliates and their relationship to physical and chemical parameters in two lakes of different trophic status

Mieczan T., Nawrot D.

Oceanological and Hydrobiological Studies

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2012

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Vol. 41, No. 2

48-56

EN

The aim of this study was to examine the community structure and vertical micro-distribution of psammonic ciliates in two lakes of different trophic status in eastern Poland. Additionally, the size and trophic structure of these microorganisms, and the influence of physical and chemical water parameters on their abundance, were analysed. Psammon samples were collected during spring, summer, and autumn of 2010. In each of the lakes samples were collected in the euarenal, higroarenal, and hydroarenal zones of the psammolittoral. In order to determine the micro-vertical distribution of ciliates, each sample was divided into two sub-samples: the upper part (0-1cm) and the lower part (1-2cm). The species diversity of ciliates decreased with depth. The tendency was particularly clear in mesotrophic lakes. Irrespective of the lake’s trophic type and arenal zones, significantly higher numbers and biomass of ciliates were recorded in the surface layer of the psammolittoral. The upper layer of sand was dominated by omnivorous taxa, whereas the deeper layer showed increases in the proportions of bacterivore species. The factors limiting the occurrence of ciliates are mainly concentrations of total organic carbon and nutrients.

4

Horizontal Distribution of Psammonic Ciliates in Two Lakes of Different Trophic Status: Relationship to Physical and Chemical Parameters

Mieczan T., Nawrot D.

Archives of Environmental Protection

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2012

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Vol. 38, no. 2

55-70

EN

The aims of this study were to identify the taxonomic diversity and abundance of psammonic ciliate communities in mesotrophic and eutrophic lakes (Łęczna-Włodawa Lakeland, eastern Poland). The effect of selected physical and chemical water parameters on ciliates community was also analysed. Psammon samples were collected during three seasons: spring, summer and autumn of 2010. In each lake, in the psammolittoral, samples were collected in the euarenal, higroarenal, and hydroarenal zones. A total of 53 ciliate taxa were recorded. The highest value of the Shannon-Weaver index was recorded in summer in eutrophic lake (2.79). At the same time in mesotrophic lake, a lower value of the index was determined (0.79). The mean numbers of ciliates ranged from 516 ind.cm-3 in the eutrophic lake to 191 ind. cm-3 in the mesotrophic lake. In eutrophic lake, the highest number of ciliates was recorded in the euarenal (649 ind. cm-3), and the lowest in the higroarenal (425 ind. cm-3). In the mesotrophic lake, the highest average numbers were determined in the higroarenal (235 ind. cm-3), and the lowest in the hydroarenal (155 ind. cm-3). Irrespective of the lake trophy, Hymenostomata (Paramecium sp., Glaucoma sp., Uronema nigricans) occurred in the highest numbers (from 13 to 95%). The results demonstrated that N-NH4, P-PO4 and TOC can strongly regulate the abundance and taxonomic composition of ciliates. The strongest correlations between numbers of ciliates and physical and chemical water parameters were observed in the higro- and hydroarenal zones of the eutrophic lake.

PL

Celem pracy było poznanie struktury jakościowej i ilościowej orzęsków psammonowych w jeziorze mezotroficznym i eutroficznym (Pojezierze Łęczyńsko-Włodawskie). Analizowano również wpływ wybranych właściwości fizycznych i chemicznych wód na kształtowanie się tego specyficznego zespołu mikroorganizmów. Próby psammonu pobierano wiosną, latem i jesienią 2010 roku. W każdym zbiorniku, w psammolitoralu próby pobierano w euarenalu, higroarenalu i hydroarenalu. Łącznie stwierdzono 53 taksony orzęsków. Średnie zagęszczenie orzęsków wyniosło 516 osobn. cm-3 w jeziorze eutroficznym, zaś w mezotroficznym było niemal 2 razy niższe i osiągało 191 osobn. cm-3 piasku. W jeziorze Sumin najwyższe średnie zagęszczenie zanotowano w euarenalu 649 osobn.cm-3, najniższe zaś w higroarenalu (425 osobn. cm-3). W jeziorze mezotroficznym najwyższe średnie wartości liczebności zanotowano w higroarenalu 235 osobn. cm-3, najniższe zaś w hydroarenalu 155 osobn. cm-3. Najwyższą wartość wskaźnika Shanonna-Weavera odnotowano latem w jeziorze Sumin (2.79), w tym samym czasie w jeziorze Piaseczno odnotowano najniższą wartość tego współczynnika (0.79). Niezależnie od trofii jeziora największy udział w ogólnej liczebności orzęsków osiągały Hymenostomata (Paramecium sp., Glaucoma sp., Uronema nigricans) stanowiące od 13 do 95% ogólnej liczebności orzęsków. Stwierdzono istotne zależności pomiędzy obfitością orzęsków, a stężeniami w wodzie związków biogennych oraz całkowitego węgla organicznego, przy czym najsilniejsze korelacje odnotowano w strefach higro- i hydroarenalu jeziora eutroficznego.

5

Vertical microzonation of testate amoebae and ciliates in peatbog waters in relation to physical and chemical parameters

Mieczan T.

Polish Journal of Ecology

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2010

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Vol. 58, nr 4

729-740

EN

Peatbogs have both horizontal and vertical differences in moisture, pH, light and nutrient availability. Micro-distribution of testate amoebae taxa has been observed along the Sphagnum stem but there is no data concerning the vertical micro-distribution of protozoa in water column under the peatbog surface and in the interstitial waters. The research was made in a small (ca 16 ha) peatbog complex in the eastern Poland. Vertical microzonation of testate amoebae and ciliates in relation to physical, chemical and biological parameters (peat porosity, temperature, dissolved oxygen, chlorophyll a, TN, TP, DOC and TOC) in Sphagnum hollows, mud bottom hollows and interstitial waters in peatbog were studied. Samples were taken once a month from April to November 2009 from three layers: free water mass up to 10 cm (FW), bottom water (BW) and interstitial, pore water - IW (water between particles of peat on depth 20-25 cm). During each sampling occasion 3 samples were collected from each site. At each type of micro-habitat and each sampling date water was sampled using a plexiglass core. The water column sampled from the top surface to the bottom was 25 cm high. Interstitial waters were collected from mini-piezometers located into the peat. Temperature, dissolved oxygen, conductivity, chlorophyll a and nutrients contents were always lower in interstitial water than in free and bottom waters. The highest numbers of testate amoebae and ciliates taxa occurred in the bottom water (31 and 13 taxa, respectively) and became much lower in interstitial water (17 and 5 taxa, respectively). The density and biomass of protozoa differed significantly between the studied layers, with the lowest numbers in the interstitial water and the highest in the bottom water. Ordination analysis indicated that chlorophyll a, TOC and TP can strongly regulate the abundance and species composition of protozoa. The RDA ordination showed that the testate amoebae species can be divided into three groups associated with: 1) free water mass, 2) bottom water and 3) interstitial water, while the ciliate species into two groups associated with: 1) interstitial water and 2) free water mass and bottom waters. The free water mass and bottom water were dominated by mixotrophic taxa, whereas the deepest layer showed the increase of the contribution of small, bacterivorous species. In all the examined micro-habitats the highest abundance and biomass of these microorganisms occurred in early spring and late autumn, while the lowest values were recorded in late summer.

6

Effect of vegetation patchiness and site factors on distribution and diversity of testate amoebae and ciliates in peatbogs

Mieczan T.

Polish Journal of Ecology

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2010

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Vol. 58, nr 1

135-144

EN

Testate amoebae and ciliates are common inhabitants of moist soils, lakes and peatbogs. These microorganisms are important consumers of bacteria, flagellates and algae; they also participate in transformation of the organic matter and nutrient regeneration. The complexity of micro-environmental conditions present in peatbogs and the challenges associated with the proper sampling may partly explain the fact that these microorganisms are still much less studied than other components of the ecosystem. The influence of emergent and submerged plants on community composition, abundance and biomass of testate amoebae and ciliates were investigated in two peatbogs in the eastern Poland. The raised and carbonate bogs selected for this study were considered to be representative of the bogs of the region and contained a broad diversity of habitats. Samples were collected in patches of Sphagnum angustifolium (C.C.O. Jensen ex Russow), Sphagnum cuspidatum Ehrh. ex Hoffm., Sphagnum palustre L., belts of Phragmites australis (Car.), Typha latifolia L., Carex acutiformis Ehrhart., Calliergonella cuspidata (Hedw.) and beds of Utricularia sp. Sampling was done on a monthly basis from April to November. At each plant patch (microhabitat) and each sampling date the water was sampled using a plexiglass core (length 1.0 m, [Radius]50 mm). Comparison of the species number, abundance and biomass (estimated in C organic units) of testate amoebae and ciliates between Sphagnum patches did not show statistically significant differences. The significant differences were noted in patches of plants in carbonate peatbog. The highest species number (40-46) was found in the Utricularia and Calliergonella, and the lowest richness (26-20) in the Typha, Phragmites and Carex. The density and biomass of protozoa communities, increase together with the abundance and the level of the complicated spatial structure of the plants. Based on differences in plant structure, two groups of habitats with similar patterns of size-related testate amoebae and ciliate distribution were distinguished. The first group consisted of three vegetated zones of smooth stem structure (Phragmites, Typha and Carex), the second group comprised plant species, which were more complex (Sphagnum, Utricularia and Calliergonella). In the redundancy analysis, water level, pH, concentration of TP, chlorophyll a and TOC together explain 45% of the variation in the species distribution data. The contribution of conductivity, dissolved oxygen TN and DOC was not (or marginally) statistically significant.

7

The influence of emergent and submerged macrophyte beds on ciliate communities in a shallow lake

Mieczan T.

Oceanological and Hydrobiological Studies

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2010

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Vol. 39, No.4

107-115

EN

Relationships between ciliates and the presence of emergent and submerged vegetation were studied in a shallow lake in eastern Poland. Samples were collected in zones of Phragmites, Typha, Batrachium, Elodea, Stratiotes and from the open water zone. The abundance and biomass of ciliates were significantly higher at sites with structurally most complex plants than in the open water or sparsely vegetated sites. The redundancy analysis indicated that bacterial abundance and total organic carbon were the most influential variables that determine the distribution of ciliates. However, chlorophyll a and Ptot have a lesser influence on the distribution of these microorganisms. Based on differences in macrophyte structure, two groups of habitats with similar patterns of size-related ciliate distribution were distinguished. The first group consisted of three vegetation zones of sparse stem structure and the open water zone, the second group comprised submerged macrophyte species, which were more complex.

8

Influence of type of substrate and water chemistry on the structure and succession of periphytic ciliate communities in hypertrophic lake

Mieczan T., Puk A.

Archives of Environmental Protection

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2010

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Vol. 36, no. 2

13-24

EN

The aims of the study was to establish whether differences exist between periphytic ciliate communities on different substrates; to determine whether colonization time would yield an abundance and taxonomic composition of ciliates; to assess the effect of physical and chemical factors on the distribution of ciliates in a shallow hypertrophic lake. Generally the species richness as well as the abundance of periphytic ciliates are determined mostly by the habitats and chemical properties of the waters (especially the content of total organic carbon and nitrate nitrogen), and, to a lesser extent, by the type of the colonized substrate. Moreover, exposition time of the substrates affected both an increase in the richness of periphytic ciliates and the changes in their trophic structure. At the beginning of the experiment the substrates were intensively colonized by typically bacterivorous species, yet prolonged exposition time resulted in an increasing proportion of omnivorous species.

PL

Celem pracy było porównanie składu taksonomicznego i liczebności zespołu orzęsków peryfitonowych zasiedlających różne podłoża; określenie, w jaki sposób czas ekspozycji podłoży wpływa na obfitość tych mikroorganizmów oraz analiza zależności pomiędzy wybranymi właściwościami fizyczno-chemicznymi wód a orzęskami w jeziorze hypertroficznym. Wykazano, że zarówno bogactwo gatunkowe jak i obfitość orzęsków peryfitonowych w największym stopniu determinują zasoby pokarmowe siedliska oraz właściwości chemiczne wód (głównie zawartość całkowitego węgla organicznego oraz azotu azotanowego), w mniejszym zaś stopniu rodzaj kolonizowanego podłoża. Czas ekspozycji podłoży wpływał zarówno na wzrost obfitości peryfitonowych orzęsków jak i zmianę ich struktury troficznej. Na początku eksperymentu podłoża były intensywnie kolonizowane przez gatunki typowo bakteriożerne, wraz ze wzrostem czasu ekspozycji podłoży wzrastał udział gatunków wszystkożernych.

9

Diversity and vertical distribution of planktonic ciliates in a stratified mesotrophic lake: relationship to environmental conditions

Mieczan T.

Oceanological and Hydrobiological Studies

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2008

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Vol. 37, No.1

83-95

EN

The density and biomass of planktonic ciliates significantly differed between sample sites in a deep, mesotrophic lake, with the lowest numbers in the hypolimnion and the highest in the epilimnion. The community composition varied greatly with depth. Oligotrichs dominated in the epilimnion, where prostomatids and peritrichs were also important components of the community. The density of oligotrichs and peritrichs decreased in the metalimnion, and they were absent from the hypolimnion. In the deep metalimnion the most abundant groups were prostomatids, haptorids and scuticociliates. In the hypolimnion, the ciliate community was dominated by scuticociliates and heterotrichs. In the epilimnion and metalimnion a significant positive correlation was observed between ciliate numbers, chlorophyll a and heterotrophic flagellate density. In all three zones the number of ciliates was most strongly correlated with water temperature, concentrations of total organic carbon (TOC), total phosphorus (Ptot) and bacterial density, whilst in the hypolimnion there was a significant correlation between ciliate numbers and the dissolved oxygen concentration.

10

Influence of water chemistry on the structure of planktonic ciliate communities across a freshwater ecotone in the eutrophic dam reservoir (Eastern Poland)

Mieczan T., Tarkowska-Kukuryk M.

Archives of Environmental Protection

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2008

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Vol. 34, no. 4

63-70

EN

The aim of the present study was to examine changes in species composition and density of ciliates in an adjacent river, ecotone and reservoir zone (Zemborzycki Reservoir, Eastern Poland). Quality and quantity structure of planktonic ciliates showed visible differences between studied zones; the highest species diversity and abundance were observed in the ecotone (water/water). The lowest species diversity and abundance were noted in the Bystrzyca River. Independent on the zone, ciliates community was dominated by bacterivorous species with the lowest proportions of algivorous taxa. The present study showed that density of protozooplankton rose with the increase of nutrients delivery and TOC concentration in water.

PL

Celem pracy była analiza zróżnicowania gatunkowego oraz liczebności orzęsków planktonowych w układzie: rzeka- ekoton (woda/woda) - zbiornik retencyjny (Zbiornik Zemborzycki, Wschodnia Polska). Zarówno bogactwo gatunkowe jak i obfitość orzęsków planktonowych były wyraźnie zróżnicowane w poszczególnych badanych strefach. Najwyższą różnorodność i liczebność orzęsków stwierdzono w strefie ekotonowcj. Najbardziej uboga jakościowo i ilościowo okazała się natomiast rzeka Bystrzyca. Niezależnie od strefy, w strukturze troficznej dominowały gatunki bakteriożerne, najniższy zaś udział miały gatunki glonożerne. Czynnikami w największym stopniu wpływającymi na występowanie protozooplanktonu były stężenia w wodzie fosforu ogólnego, fosforanów oraz całkowitego węgla organicznego.

11

Relationships among ciliated protozoa and water chemistry in small peat-bog reservoirs (Łęczna-Włodawa Lakeland, Eastern Poland)

Mieczan T.

Oceanological and Hydrobiological Studies

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2007

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Vol. 36, No.2

77-86

EN

The aims of this study were to identify the taxonomic and trophic diversity of planktonic ciliate communities occurring in small peat-bog reservoirs of various acidities (from about 3 to 6), and to assess the effects of chemical factors on them. Generally the highest numbers of ciliate taxa were recorded in high pH (>6) reservoirs, and the lowest in low pH (3.28-4.6) reservoirs. The mean numbers of planktonic ciliates in the high pH reservoirs were about three times higher than in the low pH reservoirs. However, the greatest biomass of ciliates occurred in low pH reservoirs. The results suggest that pH, conductivity and total organic carbon (TOC) are more important than total phosphorus (Ptot) in the distribution of planktonic ciliates in peat-bog reservoirs. In the low pH peat-bog reservoirs, the biggest factor affecting ciliate distribution is the pH of the water, whilst in the higher pH reservoirs the role of organic matter becomes increasingly important with increasing pH.

12

Periphytic ciliates in littoral zone of three lakes of different trophic status

Mieczan T.

Polish Journal of Ecology

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2005

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Vol. 53, nr 4

489-502

EN

Periphytic ciliate communities were investigated in three lakes of different trophic status of the Łęczyńsko-Włodawskie Lake District (Eastern Poland). Observations were made of the periphyton growing on glass-slides. Samples were taken from April to November 2000-2001. Once a month, four periphyton samples were collected in littoral zone. Seventy three ciliate taxa occurred in the studied lakes. The biggest number, 60 species, was found in eutrophic lake, a little less, 55 species, in mesotrophic lake and the least, 49 species, in dystrophic lake. The lowest density was observed in mesotrophic lake and it was 13x103 ind. m-2, being a little higher in dystrophic lake - 16x103 ind. m-2, and the highest - 20x103 ind. m-2 in eutrophic lake. All of the studied lakes were generally dominated by ciliates belonging to the order Cyrtophorida (Chilodonella uncinata Ehrenberg 1983) constituted >30% of the total numbers. In all lakes bacterivorous ciliates occurred in the highest numbers (>50%), while algivorous and histophagous . in the lowest (<5%). In the eutrophic and dystrophic lakes the proportion of omnivorous and predatory species was high. The number of significant correlations differed among lakes. In mesotrophic lake the correlation between ciliates abundance and total organic carbon was found. In eutrophic lake total number of ciliates was positively correlated with the conductivity, TP and TOC. In dystrophic lake the correlations between ciliates abundance and abiotic parameters were not observed. In mesotrophic and dystrophic lakes the content of organic matter positively correlated with the biomass of ciliates, while in eutrophic lake conductivity showed positive correlation with their biomass.

13

Różnorodność biologiczna środowisk wiejskich i podmokłych na obszarach wiejskich

Radwan S., Płaska W., Mieczan T.

Woda-Środowisko-Obszary Wiejskie

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2004

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T. 4, z. 2a

277-294

PL

Obszary wiejskie zajmują w Polsce ponad 93% powierzchni kraju. Znaczna ich część jest cenna ze względu na dużą różnorodność biologiczną. Śródlądowe ekosystemy wodne obszarów wiejskich cechuje duże zróżnicowanie, zwłaszcza na północy, w krajobrazie pojeziernym. W ich skład wchodzą: jeziora, rzeki, źródła, młaki, naturalne małe zbiorniki wodne oraz zbudowane przez człowieka zbiorniki zaporowe i stawy. Wszystkie typy ekosystemów wodnych zajmują powierzchnię 4550 km², co stanowi 1,5% obszaru Polski. Duże znaczenie w utrzymaniu różnorodności siedliskowo-krajobrazowej obszarów wiejskich mają różne typy zbiorników wodnych i torfowisk oraz rzeki. Na szczególną uwagę zasługują torfowiska węglanowe w okolicach Chełma, jeziora lobeliowe na Pojezierzu Pomorskim, drobne zbiorniki wodne otoczone torfowiskami czy też zbiorniki śródpolne. Tworzą one specyficzny, często unikalny typ krajobrazu wiejskiego, stanowiąc ostoję dla wielu rzadkich gatunków roślin i zwierząt, dzięki czemu zachowują i wzbogacają różnorodność gatunkową. Największe zagrożenie dla różnorodności gatunkowej w ekosystemach stwarzają: zanieczyszczenie wód, ich eutrofizacja, osuszanie terenu oraz gatunki inwazyjne, np.: sumik karłowaty (Ictalurus nebolusus), rak pręgowaty (Orconectes limosus) i niektóre gatunki obunogów (Amphipoda). Prowadzą one do niszczenia lub zaniku specyficznych siedlisk wielu rodzimych gatunków ryb (Pisces), innych kręgowców (Vertebrata) oraz niektórych gatunków bezkręgowców (Invertebrata) wodnych. Skutecznymi sposobami wzbogacania i ochrony różnorodności biologicznej (gatunkowej, ekosystemowej i krajobrazowej) są: restytucja gatunków, czyli wprowadzanie danego gatunku roślin lub zwierząt do siedlisk uprzednio przez niego zasiedlanych; renaturalizacja, czyli odtwarzanie naturalnego stanu w zdegradowanych ekosystemach; rekultywacja, czyli przywracanie aktywności biologicznej na terenach całkowicie zdegradowanych.

EN

Rural areas occupy over 93 % of the country area in Poland . Significant part of these areas is valuable for their high biodiversity. Inland aquatic ecosystems of rural areas are characterized by a high diversity, especially in the lake landscape of Northern Poland . They consist of lakes, rivers, springs, bog-springs, small natural water reservoirs, dammed reservoirs and ponds. All types of water ecosystems cover the area of 4550 km۶ which makes 1.5 % of Poland 's area.Different types of water reservoirs, peat bogs and rivers have great importance for maintaining habitat and landscape diversity of rural areas. Special attention should be paid to carbonate peat bogs in the vicinity of Chełm, Lobelia - type lakes in Pomeranian Lakeland, small water reservoirs surrounded by peat bogs or mid-field water bodies which create specific and unique type of rural landscape, being refuges for many rare species of plants and animals. They also preserve and enrich species' diversity. The most dangerous for species diversity in water ecosystem proved to be the pollution of water, eutrophication, the so-called land reclamation and the invasion of exotic species such as: brown bullhead, spiny-cheek crayfish and some species of amphipods. All these factors lead to the destruction or disappearance of specific habitats for many native species of fish and some invertebrates. The effective ways of enriching and protecting the diversity (at species, ecosystem and landscape level) are: species restitution, i.e. introducing some plant or animal species to habitats previously settled by them, renaturalization, i.e. reconstruction of the natural status of degraded ecosystems; reclamation, i.e. restoration of biological activity in wholly devastated areas.