Stages Of Vegetation Succession Research Articles

Regenerative Role of Soil Seed Banks of Different Successional Stages in A Saline-alkaline Grassland in Northeast China

Soil seed banks can act as a potential seed source for natural revegetation and restoration. However, in a saline-alkaline grassland, it remains unclear how the stages of vegetation succession affect the characteristics of soil seed banks and the potential of soil seed banks of different successional stages for vegetation restoration. In this study, seasonal changes of the soil seed bank, and seed production and dispersal dynamics along degradation successional gradients were investigated in a saline-alkaline grassland in Northeast China, where the dominant grass during the 1960s, Leymus chinensis was replaced with the secondary successional order of Puccinellia chinampoensis, Chloris virgata, and Suaeda salsa, together with bare patches. It was found that the soil seed bank composition varied according to the changing vegetation and had the highest species richness (7–16) in the climax successional stage, but had a low Sorensen similarity (0.22–0.37) with the aboveground vegetation. There was a high seed density of the soil seed bank (21 062–62 166/m2 in August and December) and also high Sorensen similarity index values (0.47–0.60) in the secondary successional stages of P. chinampoensis, C. virgata, and S. salsa. In bare patches, there were many seeds in the soil seed bank and some seedlings also appeared in the aboveground vegetation, indicating the existence of a persistent soil seed bank. Seed density and species richness differed substantially among the different successional stages, which was related to the reproductive characteristics of the standing plants in vegetation communities. Due to the lack of propagules of perennial species, especially the climax species of L. chinensis, in the soil, the successful restoration of the degraded saline-alkaline grassland was not possible. The study proved that in a degraded saline-alkaline grassland dominated by biennial or annual species, the soil seed bank was important for the revegetation of the current dominant plants, but not for the restoration of the original target species. Therefore, it is necessary to induce seeds or other propagules of the target perennial species.

Vascular plant‐mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change

Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that vascular plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of vascular plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb-14 C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.

Potenziale städtischer Gewerbebrachflächen für eine integrierte Stadtentwicklung

Urban brownfields have been an internationally recognised topic for many years and exist in industrialised countries worldwide. After decades of severe shrinkage, Leipzig, Germany, is now a fast-growing city. It serves as an excellent example to discuss the redevelopment of urban brownfields for an integrated urban development. We investigate the potentials of brownfields through land-use monitoring. In our field work, we mapped 783 brownfields in all of the city's commercial zones, including size, geographic position and spatial assignment, land surface characteristics and surrounding infrastructure. Spatial distribution of brownfields in the planning districts as well as land-use pat- terns was of great concern regarding vegetation succession stages and sealed surfaces. Infrared aerial colour photos supported our field information, gathered in a GIS-based information tool of urban districts for the planning division. More than 80% of all derelict land is less than one hectare in size and thus a major challenge in terms of individual recycling. Private ownership hampers redevelopment. Due to advanced succession stages there is a high potential for renaturalisation into coherent green spaces. Pressures on land use demand the readjustment of green infrastructure development in an urban planning masterplan. The project is based on scientific collaboration with the City of Leipzig's Authority of Urban Planning, Germany.English title: Potential Performance of Commercial Urban Brownfield Sites in Integrated Urban Development – Monitoring for Sustain- able Land-Use Management Based on the Ex- ample of the City of Leipzig

The early stages of vegetation succession in a recovering Eucalyptus plantation: A case study from Sri Lanka

Changes in non-herbaceous species were recorded between 2006 and 2013 to understand the secondary succession in a harvested Eucalyptus camaldulensis plantation near Maragamuwa, Naula in Sri Lanka. Composition, mean abundance and absolute abundance were recorded in 40 cleared, 20 × 20 m2 quadrats placed in eight 1 ha blocks in two types of locations: harvested eucalypt plantation away from the natural forest (MP) and harvested blocks next to a natural forest (MT). A total of 77 species were recorded in 2006 in MP declining to 55 in 2013, while the 61 species recorded from MT dropped to 48. Over time the number of super-abundant species with >100 individuals decreased from 14 in MP in 2006 to 5 in 2013. In the same period, numbers declined from 13 to 3 species in MT. Changes in numbers of individuals differed significantly in both MP and MT between 2006, 2009 and 2013 years (p 0.05). MP had lower proportions of forest species than that in MT. The proportion of forest species increased in MT, whilst remained similar in MP. As expected, both the abundance and richness decreased in MP and MT over time.

Tree ferns dominate secondary succession in abandoned pineapple plantations around Manu National Park, Peru

Habitat management and restoration in buffer zones of national parks is critical for maintaining ecosystem services and biological connectivity in and around the parks’ core protected areas. Vegetation succession in abandoned plantations in buffer zones may take different paths that reach climax ecosystems in more or less time depending on the conditions of initial succession, thus enhancing or hindering biological connectivity and ecosystem services. This study documents the dominance of tree ferns in the initial stages of vegetation succession on abandoned pineapple plantations on the Andean foothills around Manu National Park, Peru, and discusses the role it may have on ecosystem restoration. Four years after abandonment, tree fern gametophytes grow under the shade of pineapple plants and melastomes. After 6-10 years of succession, the vegetation is dominated by a tree fern community composed of at least eight species, of which the most common are by far Cyathea delgadii and Cyathea microdonta. Cyathea microdonta functions as a short-lived pioneer, reaching its peak of live stem density in 6 to10 years and dying off in older plots. Cyathea delgadii, on the other hand, continues to grow and persists beyond 10 years of succession. Areas adjacent to abandoned pineapple fields have few tree ferns and higher tree species diversity, suggesting that pineapple agriculture and the resulting tree fern community may be a longer pathway to reach climax vegetation stages than other types of plantation.

Tree ferns dominate secondary succession in abandoned pineapple plantations around Manu National Park, Peru

Habitat management and restoration in buffer zones of national parks is critical for maintaining ecosystem services and biological connectivity in and around the parks’ core protected areas. Vegetation succession in abandoned plantations in buffer zones may take different paths that reach climax ecosystems in more or less time depending on the conditions of initial succession, thus enhancing or hindering biological connectivity and ecosystem services. This study documents the dominance of tree ferns in the initial stages of vegetation succession on abandoned pineapple plantations on the Andean foothills around Manu National Park, Peru, and discusses the role it may have on ecosystem restoration. Four years after abandonment, tree fern gametophytes grow under the shade of pineapple plants and melastomes. After 6-10 years of succession, the vegetation is dominated by a tree fern community composed of at least eight species, of which the most common are by far Cyathea delgadii and Cyathea microdonta. Cyathea microdonta functions as a short-lived pioneer, reaching its peak of live stem density in 6 to10 years and dying off in older plots. Cyathea delgadii, on the other hand, continues to grow and persists beyond 10 years of succession. Areas adjacent to abandoned pineapple fields have few tree ferns and higher tree species diversity, suggesting that pineapple agriculture and the resulting tree fern community may be a longer pathway to reach climax vegetation stages than other types of plantation.

Assessment of Land Use-Cover Changes and Successional Stages of Vegetation in the Natural Protected Area Altas Cumbres, Northeastern Mexico, Using Landsat Satellite Imagery

Loss of vegetation cover is a major factor that endangers biodiversity. Therefore, the use of geographic information systems and the analysis of satellite images are important for monitoring these changes in Natural Protected Areas (NPAs). In northeastern Mexico, the Natural Protected Area Altas Cumbres (NPAAC) represents a relevant floristic and faunistic patch on which the impact of loss of vegetation cover has not been assessed. This work aimed to analyze changes of land use and coverage (LULCC) over the last 42 years on the interior and around the exterior of the area, and also to propose the time of succession for the most important types of vegetation. For the analysis, LANDSAT satellite images from 1973, 1986, 2000, 2005 and 2015 were used, they were classified in seven categories through a segmentation and maximum likelihood analysis. A cross-tabulation analysis was performed to determine the succession gradient. Towards the interior of the area, a significant reduction of tropical vegetation and, to a lesser extent, temperate forests was found, as well as an increase in scrub cover from 1973 to 2015. In addition, urban and vegetation-free areas, as well as modified vegetation, increased to the exterior. Towards the interior of the NPA, the processes of perturbation and recovery were mostly not linear, while in the exterior adjacent area, the presence of secondary vegetation with distinct definite time of succession was evident. The analysis carried out is the first contribution that evaluates LULCC in this important NPA of northeastern Mexico. Results suggest the need to evaluate the effects of these modifications on species.

Let native species take their course: Ambrosia artemisiifolia replacement during natural or “artificial” succession

Ambrosia artemisiifolia is able to dominate the early stages of vegetation succession in open/disturbed habitats, spreading out into available empty niches, after which it can be progressively replaced by perennial plants. In this study, we considered the time-span in which the species is suppressed during active (restoration actions) and passive (spontaneous) vegetation recovery. In particular, we envisaged that A. artemisiifolia growth and fitness may be strongly reduced and that the species may rapidly be suppressed within a short time during succession as a consequence of the increase of vegetation cover, both natural or artificially induced, in a disturbed area of northern Italy. Three different treatments were applied within an abandoned quarry area commonly invaded by A. artemisiifolia: (i) spontaneous succession i.e. (control), (ii) hayseed and (iii) a commercial seed mixture. We determined the effect of mixtures of grassland species, established from native hayseed or from a commercial seed mixture, on A. artemisiifolia growth and fitness traits over time in comparison to a non-seeded area left to spontaneous succession. The results demonstrated that, after the first growing season, compared with spontaneous succession, both commercial seed and hayseed resulted in a strong reduction of A. artemisiifolia abundance and growth rate, in terms of both vegetative and reproductive traits. After the second growing season, A. artemisiifolia was completely suppressed in the commercial seed treatment, and after the third growing season it was also suppressed in the spontaneous succession and hayseed treatments. This study indicated that both active and passive vegetation recovery (by niche filling and competitive exclusion) could be used as methods individually or in combination with other methods, such as mowing and biological control, to suppress A. artemisiifolia from anthropogenic habitats.

English

Many people in Uganda, particularly in the rural areas depend on herbal medicine for health care. Although, medicinal plants are collected from different habitats, most of them are collected from the wild. Claims indicate that men use more forest products than women; and that women prefer younger vegetation succession stages as compared to those preferred by men for harvesting medicinal plants. However, there was no documented evidence to ascertain these claims. This study documented medicinal plants and investigated the influence of gender in the collection of these plants around Bwindi Impenetrable National Park. The plants used by various categories of herbalists were collected, identified and listed. The differences between herbalist categories regarding medicinal plant collection and use were studied using both qualitative and quantitative participatory rural appraisal (PRA) methods. Two hundred and ninety five species encompassing all growth forms were listed with herbs and shrubs being most frequently used and majority (70%) of these occurred outside the forest. Most of the mentioned plants were reported to be used in mixtures while leaves were reported as the most frequently used plant part. Key words: Medicinal plants, Bwindi Impenetrable National Park, conservation.

The role of willowherbs (Epilobium) in the recovery of vegetation cover a year after use of herbicide: a case study from Central Lithuania / Ožkarožių (Epilobium) vaidmuo atsikuriant augalijai praėjus metams po herbicido panaudojimo: tyrimas centrinėje Lietuvos dalyje

AbstractSeveral species of willowherb (Epilobium) are considered as agricultural weeds and their prevalence has become an increasing problem in agriculture. The aim of this study was to investigate the role of willowherb plants in the initial stage of vegetation succession a year after the use of glyphosate. The study was based on the examination of thirteen willowherb specimens collected in the apple orchard of 0.2 ha area in August 2008, one month after glyphosate treatment, and vegetation field investigations in the same orchard in July 2009. The coverage of herb layer, the abundance and life stages of Epilobium plants in twenty plots of 1 m2in size were investigated. The specimens of willowherbs, which survived the glyphosate application in 2008, were identified as Epilobium ciliatum and E. tetragonum. A year after the glyphosate treatment, the willowherb plants prevailed in the vegetation. One alien (E. ciliatum) and three native (E. hirsutum, E. parviflorum and E. tetragonum) species of willowherb were found. E. ciliatum was the most abundant. This species was characterized by the highest number of reproductive and virginile plants. E. parviflorum and E. tetragonum plants were abundant with a very high proportion of reproductive plants. Only pre-reproductive plants of E. hirsutum occurred in the study plots. The reproductive plants represented more than one third of the total number of willowherb plants. The distribution patterns of willowherb species in the plots were very variable.

Small Mammal Abundance in Mountain Big Sagebrush Communities after Fire and Vegetation Recovery

Abstract. Managing fire for the conservation of biodiversity is a widespread challenge. An important disturbance mechanism in big sagebrush (Artemisia tridentata) communities, fire has well-known effects on vegetation structure but poorly described consequences for sagebrush wildlife communities. We estimated the abundance of small mammals in relation to fire history in mountain big sagebrush (A. t. ssp. vaseyana) communities by way of a chronosequence approach that included 3 wildfires and adjacent unburned areas. We compared patterns of mammal community succession with expectations of the habitat accommodation model by associating responses of mammals to change over time in vegetation structure. Burned study sites were at various stages of vegetation succession from 7 to 19 years following fire. Shrub canopy cover ranged from 9% to 36% and was not fully recovered on the plots at 19 years after fire. Only Belding's ground squirrel (Urocitellus beldingi) demonstrated a measurable response to fire that was...

Aboveground carbon stock, allocation and sequestration potential during vegetation recovery in the karst region of southwestern China: A case study at a watershed scale

Karst landscape in southwestern China is one of the most typical landscapes developed on carbonate bedrock and has the largest area in the world. Carbon sequestration potentials during secondary karst vegetation recovery remain uncertain. Based on the vegetation map and 87 sampling plots at five stages of natural vegetation succession, this study estimated aboveground (AG) vegetation carbon stocks and dynamics at a watershed scale. AG carbon density of grasslands, shrublands, shrub forests, secondary forests and primary forests was 1.70, 4.15, 22.3, 70.3, 142.2Mgha−1, respectively. The ten most important species stored 71.6–96.1% of total AG carbon stock, indicating that carbon pool in karst vegetation was determined by a few dominant species. Main contributors to AG carbon stock shifted from individuals in small diameter classes in shrublands to individuals in large diameter classes in primary forests, indicating that carbon increases in the early vegetation succession resulted from high recruitment of woody plants, while carbon accumulations in the later forests were mainly due to tree growth. The long time required for secondary forests to recover carbon density to the level of primary forests could be explained by the slow speed of large evergreen trees reaching a high level of dominance during secondary succession on the harsh habitats. The total AG carbon stock of the studied watershed (7.50×103ha) was 85.9×103 Mg, of which paddy fields, dry lands, grasslands, shrublands, shrub forests and secondary forests accounted for 22.6%, 3.49%, 0.34%, 5.97%, 12.3% and 55.3%, respectively. The AG carbon stock in this watershed would increase by 92.5% in 50–100 years and by 4.40 times in 140–200 years if the degraded vegetation types could continue to develop into mature forests. Although carbon density of karst forests was significantly lower than that of the forests on non-karst habitats in the same latitudinal zone, the degraded karst vegetation showed a great carbon sequestration potential due to the large distribution area in southwestern China.

Recovering ability of deciduous Oak Forest after different stages of tree cutting in Central Italy

This study, performed in the frame of the European PROmotion of FORest BIOmass in the MEDitterranean project, addressed the spatio-temporal variations among stands with different ages of tree cutting using data on species composition and vertical structure collected by phytosociological survey. In the Mediterranean region coppicing and tree cutting are the most widespread management regime affecting the forest composition, structure and recovery. All woodlands investigated in central Italy belong to sub-mediterranean deciduous oak forest dominated by Quercus cerris and Q. frainetto. An integrated phytosociological and ecological approach was utilized to determine the forest changes after tree cutting. A multivariate ordination (nonmetric Multidimensional Scaling, NMDS) was applied to the floristic and environmental dataset. NMDS distinguished, along the first axis, two groups of releves related to different age of tree cutting: Young—Y-stands (period: after 2000, cutting from 13 years ago), were well separated from Old—O-stands (period: 1950 and 1970, cutting from 43–63 years ago) and Middle (M) stands (period: 1970 and 2000, cutting from 13–43 years ago). On the same ordination the environmental variables related to climate, topography and vertical structure were projected. The Indicator species of Young and Old/Middle groups, respectively, were detected via the indicator species analysis: thermoxerophilous woody species of the Mediterranean woodlands together with deciduous thermophilous species were indicators of Young stands; whereas sciaphilous and mesophilous herbaceous species were indicators of Old/Middle stands. Significant differences in species composition and vertical structure distinguished the three groups of stands and the Young stands, with a turnover of 13 years, were particularly affected. Coverage of species and layers vary greatly in relationship with the years of cutting following the stages of vegetation succession. Finally, the climate strongly interacts with the forest management.

Habitat modification as a means of restoring crested auklet colonies

ABSTRACTSeabirds that forage in dense groups can be especially vulnerable to anthropogenic threats at sea. To mitigate these threats to populations, nesting habitat restoration may be a viable option by reducing negative density dependence. Accordingly, we undertook a before‐after control‐impact (BACI) experiment to test whether habitat modification could be an effective means of restoring nesting habitat of crested auklets (Aethia cristatella) breeding on Gareloi Island, Alaska, USA. Despite supporting large numbers of crevice‐nesting auklets, many lava flows at Gareloi Island are in a stage of late vegetative succession that may prevent birds from accessing subterranean nesting habitat. We hypothesized that crested auklet density is highest in unvegetated blocky and porous lava, and predicted that removing vegetation from the surface would allow new recruits to secure previously unavailable nesting sites. In 2009 and 2010, we delineated 34 200‐m2 plots throughout the southeast colony at Gareloi, and color marked a subset of crested auklets landing in each plot to measure movement and abundance. We removed vegetative overgrowth and peat from half of each plot at the end of the 2009 (4 plots) and 2010 (30 plots) breeding seasons. Before and after vegetation removal, we counted the number of active nesting sites and calculated the ratio of banded to un‐banded breeders on the surface of each plot half. Overall, active nesting sites, number of individuals on the surface, and number of breeders landing did not increase after vegetation removal. However, among banded individuals that moved among plot halves, birds were 1.7 times more likely to move to a de‐vegetated plot half. Based on our experimental results, we found no evidence that vegetation removal increased crested auklet numbers at Gareloi Island, and thus in the short term this may not be a viable option for increasing crested auklet abundance. © 2016 The Wildlife Society.

Late Holocene paleoenvironments of the floodplain of the Solimões River, Central Amazonia, based on the palynological record of Lake Cabaliana

The core PD-67 of 160 cm depth was collected from the delta of Lake Cabaliana situated on the Solimoes River. Seventeen samples were removed for palynological and sedimentological analysis and three for radiocarbon analysis. Two dry periods, both in the Late Holocene, were observed (2800-2550 cal yr BP, 1450-550 cal yr BP) separated by a wetter phase (2550-1450 cal yr BP). In 2800-2550 cal yr BP, varzea forests of Alchornea, Symmeria, Cecropia, Alternanthera and Asteraceae were predominant. Beginning in 2,550-1450 cal yr BP, the varzea was characterized by pioneer elements, such as Cassia, Laetia, Mabea, Symmeria and Cecropia, and by the expansion of Poaceae, Cyperaceae, Sagittaria, Montrichardia and Asteraceae. In 1450-550 cal yr BP the succession of varzea continued with Pseudobombax, Laetia, Luehea/Lueheopsis and Ryanaea increasing simultaneously with the terra firme vegetation of Rutaceae, Sapotaceae, Styrax, Scleronema, Anthurium, Araceae, pteridophytes and Pariana. The successional dynamics at Lake Cabaliana indicated that the local varzea had become established recently, and is composed of a mosaic of different successional stages of vegetation influenced mainly by flood pulse and variation in rainfall. It is therefore possible to propose that the recent climate history of Central Amazonia reflects changes in rainfall patterns in the basin.

Impact of secondary vegetation succession on soil quality in a humid Mediterranean landscape

Former agricultural fields are increasingly abandoned in several regions in Southern Europe. In many cases this leads to vegetation succession which may have a direct impact on soil quality, biodiversity and hydrological connectivity. The aim of this study is to provide insights on the role of vegetation succession in response to land abandonment on soil quality changes, while keeping aspect into consideration. Information on soil quality change is incomplete and highly scattered especially in the Mediterranean and deserves more attention.Four different stages of land use change and vegetation succession (i.e. agricultural field, abandoned field, young forest, semi-mature forest) were selected and sampled on both north-, and south-facing slopes. For each of the eight conditions six representative sites were sampled. During vegetation succession soil organic carbon (SOC) content and total nitrogen (TN) content, and aggregate stability significantly increased. With increasing SOC, TN and aggregate stability the bulk density and pH decreased. In addition, the parameters SOC, TN and water retention are impacted by aspect. SOC contents increased slower over time on north exposed slopes, but were higher after 50years. Carbon stocks showed a similar trend but were not different after 50years for both studied expositions, due to aspect related changes in dry bulk density over time. Soil water availability was 24% higher for north-facing slopes. Soil water availability however did not change over time. Largest increase in soil quality was observed in the first 30years after abandonment.

Succession is threatening the large population of Lycopodiella inundata (L.) Holub. on anthropogenic site

Lycopodiella inundata is an endangered, wetland species, able to occur in secondary, anthropogenic habitats. The article presents five-year changes in the occurrence of Lycopodiella inundata on the one of the largest stands in Central Poland. Chosen parameters of population were examined in different stages of vegetation succession. In open thickets the number of fertile stems was near three times higher and amounted above eight hundred fertile stems per square meter. In contrast, in patches with dense herb- and shrub-layer, the low number of fertile stems of L. inundata, have been observed. At anthropogenic sites, where L. inundata occurs, active protection should be made for the inhibition of succession and for the rejuvenation of habitat.

Decline of the Endangered Morro Bay Kangaroo Rat in California

AbstractThe Morro Bay kangaroo rat Dipodomys heermanni morroensis occurs in the vicinity of Morro Bay (specifically in and near Los Osos) in western San Luis Obispo County in coastal central California. It was listed as endangered pursuant to the U.S. Endangered Species Conservation Act in 1970 and subsequently the U.S. Endangered Species Act in 1973. Field research from the late 1950s to the mid-1980s has documented a rapid population decline. Despite many efforts, researchers have not captured the Morro Bay kangaroo rat since 1986, and the last captive individual died in 1993. We review the biology and conservation status of the Morro Bay kangaroo rat, including taxonomy and genetics, soil type and burrows, history of decline, primary causes of decline, breeding in the wild and in captivity, habitat restoration, and threats. In particular, there are two primary causes of decline. First, development (urban, agricultural, and industrial) has resulted in direct loss of habitat. Second, in the absence of fire, the early seral stages of coastal dune scrub (optimal habitat) have matured to later successional stages of vegetation, which are denser and with substantially fewer annual food plants, and which negatively impact the locomotion of kangaroo rats and change the diversity of the small mammal community with a likely increase in competition. In 2016 only pockets of habitat remain, with optimal habitat comprising an estimated 1% of the historical geographic range. Although researchers have not demonstrated predation by domestic cats, it is likely a major threat and we suspect it has contributed to the decline based upon a review of the literature. In 2011 we observed potential signs of the Morro Bay kangaroo rat at two historical areas, which suggests it may be persisting at extremely low densities in a few isolated colonies. In addition, we could not obtain permission to survey on four private properties with potential habitat. In consideration of the vast loss and fragmentation of its habitat, along with the continuing and pervasive threats, the Morro Bay kangaroo rat is clearly conservation-reliant. We believe that without urgent human intervention, the Morro Bay kangaroo rat will soon become extinct if it is not already.

PROPOSTA DE VALORAÇÃO ECONÔMICA DE DANOS AMBIENTAIS COMETIDOS CONTRA A FLORA

OO meio ambiente e considerado um bem difuso relacionado aos interesses da coletividade. Por isso, a Constituicao Federal do Brasil preve o principio da reparabilidade integral do dano ambiental, que pode ser definido como as alteracoes negativas em recursos naturais que afetem adversamente o homem ou a natureza. Nestes casos, faz-se necessaria a valoracao das lesoes ambientais, visando definir os beneficios dos ecossistemas que foram alterados e instrumentalizar processos indenizatorios. Dessa forma, objetivou-se a confeccao de um metodo simples e direto de valoracao de danos cometidos contra a flora no RS. Esta pesquisa foi norteada pelo Decreto Federal 6514/2008 e pelo Metodo do Custo de Reposicao, e teve como ponto de partida a extracao dos principais danos ambientais cometidos no noroeste do estado. Tambem foram utilizados indices referentes aos estagios sucessionais da vegetacao, extraidos da Resolucao CONAMA 033/2004, unidades de referencia de acordo com a protecao legal das areas, informacoes do Inventario Florestal continuo do RS e de pesquisas com empresas e orgaos do setor sobre os precos de mercado de recursos florestais na mata e os custos de um projeto de recuperacao de area degradada. O metodo para o calculo de valoracao de danos ambientais cometidos contra a flora confeccionado a partir destas informacoes pode ser expresso como Valor inicial do dano multiplicado pela unidade de referencia e pelo estagio sucessional da vegetacao mais o Custo de reposicao de um projeto na respectiva area. Conclui-se que este metodo e aplicavel nas demandas do DBIO/SEMA e de outros orgaos ambientais.

Effects of land abandonment on bird communities of smallholder farming landscapes in post-war Croatia: implications for conservation policies

Land abandonment is a widespread phenomenon in agricultural systems, especially in former communist countries of Eastern and South-eastern Europe. Moreover, Croatia was affected by acts of war which enhanced the depopulation of marginal areas impelling further land abandonment. Agricultural landscapes in Croatia are highly parcelled with various proportions of for- est habitats due to traditional smallholder farming systems. Secondary successions as a consequence of land abandonment affect farmland birds that are among the most endangered bird species in Europe. We examined bird communities along a habitat gradient in heterogeneous agricultural landscapes. We used the share of woody vegetation cover as a proxy measure for land abandonment that we classified in four classes. Our results showed no significant Shannon Wiener Index differences of bird communities along the land abandonment gradient. However, there were differences in abundances when we examined bird guilds such as farmland, forest and "other" birds separately. However, the conservation value of each of the four land abandonment classes did not show significant differences. We extracted single bird species such as the Yellowhammer ( Emberiza citrinella), Red-backed Shrike (Lanius collurio), Song Thrush (Turdus philomelos) and European Robin (Erithacus rubecula) as potential indicator species for the four examined land abandonment levels. With these four species we successfully modelled the distribution of the recorded bird assemblages at the plot level along the four vegetation succession stages. We emphasized the need to develop new and inte- grative land use management concepts for areas affected by land abandonment in order to formulate sound conservation policy. Abbreviations: AMSL-Above Mean Sea Level; CLC-Corine Land Cover; DEM-Digital Elevation Model; MRPP-Multiple Response Permutation Procedure.