Authors:J. Benitez, M. V. Lencinas, A. Huertas Herrera, and G. Martínez Pastur
Lencinas , M.V. , G.J. Martínez Pastur , P. Rivero and C.A. Busso . 2008 a. Conservationvalue of timber quality versus associated non-timber quality stands for understory diversity in Nothofagus forests . Biodiv. Conserv. 17 : 2579 – 2597
Authors:K. Mikulić, A. Radović, V. Kati, S. Jelaska, and N. Tepić
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 forest 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 integrative land use management concepts for areas affected by land abandonment in order to formulate sound conservation policy.
Authors:F. Samu, F. Kádár, G. Ónodi, M. Kertész, A. Szirányi, É. Szita, K. Fetykó, D. Neidert, E. Botos, and V. Altbäcker
Recent environmental and land use changes have made wildfires more frequent in natural habitats of the Kiskunság Sand Ridge on the Hungarian Plain. In a study initiated 2.5 years after an extensive fire that destroyed half of the area of a sand grassland — juniper, poplar forest steppe habitat, we assessed the effects of fire on two generalist arthropod groups: spiders and carabid beetles, as well as on the vegetation. Utilizing the natural experiment situation, samples were taken by pitfalls and suction sampling during a 1.5 years period in four 1 ha blocks, two of which were on the burnt part of the habitat, and two in the unburnt control. At the time of the investigation, in the burnt area the vegetation in the grass layer showed a quick but not complete recovery, while the canopy layer of the juniper bushes burnt down with no sign of regeneration. Carabid beetles and spiders showed differences in recovery after fire. In the carabid assemblages of the burnt parts — compared to the unburnt control — there were over three times more beetles, out of which significantly more represented the macropterous life form and granivorous feeding strategy. There was a higher ratio of pioneer species and a simplified assemblage structure in the burnt area, which meant that the conservation value of the carabid assemblage became lower there. In contrast, for the spider assemblage quantitative changes in abundance and species numbers were not significant, and the differences in species composition did not lead to a decrease in conservation value. Spider species in the burnt plots could not be described as pioneer species, rather they had ecological characteristics that suited the changed vegetation structure. Comparing the two groups, to repopulate the burnt areas, dispersal abilities proved to be more limiting for carabids. However, in both groups a strong assemblage level adaptation could be observed to the postfire conditions. In spiders, species with a stratum preference for the grass layer prevailed, while in carabids individuals with granivore strategy gained dominance. Thus, despite the differences in their speed, basically both assemblages tracked vegetation changes. The effect of future fires will depend on their scale, as well as land-use practices, such as grazing, that interact with fire frequency and recovery. If extensive fires in the future permanently change the vegetation, then it would also lead to a fundamental change in the arthropod fauna.
Authors:A. Huertas Herrera, M. V. Lencinas, and G. Martínez Pastur
The comprehensive assessment of environmental gradients influencing species assemblages is important for implementing new conservation strategies under climate change. This study aims to determine the multi-scale effect of altitudinal and longitudinal gradients as drivers of richness and plant community assembly in mountain landscapes of Isla de los Estados (Argentina) to identify areas with greater conservation value in Southern Patagonia. We chose three fjords across the island that extends from West to East and we categorized landscapes into four ecosystem types according to their vegetation type (forests and open-lands) and elevation (lower lands, 0-100 m.a.s.l. and upper lands, 300-400 m.a.s.l.). Forest structure, soil cover (woody debris, rocky outcrop and bare soil) and vegetation cover (vascular and non-vascular), including richness and growthforms (trees, shrubs, prostrate and erect herbs, tussock and rhizomatous grasses, ferns and inferior plants) were measured in 60 sampling areas (3 fjords × 2 vegetation types × 2 elevations × 5 replicates). ANOVAs and multivariate methods were used to analyse heterogeneity in forest structure, plant richness, and life-form. In addition, species richness and the Simpson’s diversity index were calculated to understand plant assembly at multiple-scales (α, β and γ). Our results showed that environmental gradients (altitudinal and longitudinal) are more important drivers of change of ecosystem type than forest spatial structure. Furthermore, forest structure significantly varied with altitudinal and longitudinal gradients affecting most of the studied variables. A greater similarity (in richness and cover) between open-lands of lower and higher elevations was detected, as well as between forests. Fjords showed a West-East gradient, where the western and center fjords were more closely related to each other than to the eastern fjord. A multi-scale diversity approach may play central role in improving our understanding the main environmental drivers of richness and plant community assembly in these forests, both theoretical and empirical, and may be used to identify the spatial scale at which ecosystem types have greater conservation value. This study indicates that for southern forest conservation at regional level, efforts must cover all environmental gradients, including the different vegetation types to assure ful conservation of all the species assemblages.
Authors:L. Erdős, Z. Bátori, M. Zalatnai, K. Margóczi, D. Tolnay, V. Cseh, G. Arsene, and L. Kömöczi
We compared two neighbouring alkaline grasslands from a nature conservation point of view. The two grasslands are situated in different countries, resulting in different land uses. This study characterises the vegetation of the area in focus using the categories of the General National Habitat Classification System (Á-NÉR) and compares the two sides based on naturalness categories, diversity ordering, social behaviour types, differential species and some supplementary information (e.g. waste dumps, landscape elements). Plant diversity is greater on the Romanian side, but this is mainly due to disturbance tolerants, weeds and ruderal competitors. Thus, we conclude that the grassland on the Romanian side is overgrazed. In addition, there are other undesirable processes on the Romanian side. In contrast, the Hungarian side is undergrazed. We suggest that adverse effects of grazing should be minimised using careful grazing techniques and traditional methods on the Romanian side, while grazing should be re-established on the Hungarian side. Intensive nature conservation efforts must be made if we are to protect the considerable conservation values of the grasslands, which should be protected legally.
Lake Balaton is a large, shallow lake (area: 597 km
, average depth 3.3 m) located in Western Hungary. The valleys joining the lake hold wetlands which are of high conservation value. When the water level of the lake was lowered by more than a meter in 1863, these valleys were also partially drained. In order to investigate the original state of these wetlands and the lake, the corresponding sheets of the First Habsburg Military Survey (1783–1784) were georeferenced and interpreted. The shorelines of the wetlands were compared with present-day elevation contours to create elevation profiles of the valleys. The water level of Lake Balaton was measured by comparing the depth contour lines of the georeferenced Krieger Map (1776) to the present-day elevation model of the lake floor. The results show that the valleys can be grouped into lacustrine and fluvial types, the former characterized by low slope angles, the latter by comparable steeper slopes and water retention by vegetation. The original water level of the lake was around 106.5 meters above sea level. The connections of the valleys with the lake were evaluated and priorities for focusing conservation efforts were suggested based on the geomorphology of the region.
Authors:K. Ecker, M. Küchler, E. Feldmeyer-Christe, U. Graf, and L. Waser
As conservation of sensitive habitats is a high priority issue in European environmental policy, there is considerable interest in mapping and monitoring specific habitats of high conservation value. In this study, we discuss the potential of the Swiss mire monitoring program to monitor small area habitats in sufficient detail. The monitoring scheme combines nationwide probability sampling and predictive habitat mapping based on a field data sample. Thus, it is designed to identify spatiotemporal changes at the stand level and to derive hard statistics for the sub-national level. For feasibility reasons, the thematic focus is on semi-quantitative mean indicator values derived from vegetation records. These measures provide robust estimates of essential floristic site conditions. Regression models based on CIR aerial photographs are applied to continuously map respective measures across the sample mires. The present study explores the required investment of data for model-based mapping. Exemplary mapping results are presented and validated within a reference mire. Repeated tests show that about one hundred field records are needed to guarantee optimal prediction accuracy and reliable error estimates for all target variables. The corresponding 95% error quantiles in a test data set are below 0.7. To evaluate the benefit of high resolution orthophotos (30 cm resolution), the model prediction is compared with results obtained from coarsened images. Although the original CIR images produce the best model performance, the models based on resolutions comparable to modern satellite images still show considerable potential to assess larger areas where the use of digital aerial photographs is limited. The resulting spatially-explicit in-depth information can resolve the common thematic limitations of stand-alone remote sensing applications in conservation monitoring. As the method is applicable consistently across a range of habitat types, we argue that it has the potential to become a standard method for operational monitoring of priority habitats in European nature conservation.
Authors:G. M. Pastur, M. V. Lencinas, E. Gallo, M. de Cruz, M. L. Borla, R. S. Esteban, and C. B. Anderson
Biodiversity conservation requires knowledge about the factors that influence the structure and function of biotic assemblages. In southern Patagonian Nothofagus forests, birds are the most abundant and diverse vertebrates and are known to have different requirements for nesting, breeding and feeding. Therefore, we chose this group to analyze key drivers of avian community dynamics; for conservation purposes, this information is requisite to manage Nothofagus forest landscapes and their associated biota. We first characterized forest structure and understory floristic composition in open and closed canopy broadleaved forests of mixed deciduous (MD) and mixed deciduous-evergreen (MDE) species on the southern coast of Tierra del Fuego National Park, Argentina. For each habitat, bird assemblages were assessed using point counts, checklists and mistnetting. We used ANOVAs and multivariate methods to analyze changes in bird species richness, density, and biomass as a function of habitat and seasonal characteristics. Forest structure and understory plant communities influenced avian assemblage and density; MDE forests had significantly greater species richness, but lower density than MD. Plus, particular species were associated with specific understory conditions, such as Anairetes parulus and Zonotrichia capensis whose presence was related to shrubs. Additionally, variations observed between seasons apparently were related to differential uses of each habitat type during certain times of year. Finally, it was not possible to define a single forest type with greater conservation value for birds; each had a specific bird species assemblage. Consequently, our results suggest the importance of a full representation of habitats to preserve the region’s bird diversity, which also has been described for forest invertebrates and understory plants.
Authors:P. Sengl, M. Magnes, L. Erdős, and C. Berg
How should the somewhat vague term of restoration success be measured? This is a critical question rooted in European law, where in fact the creation of proper replacement habitats is a prerequisite for permitting projects that trigger a loss of species or habitats. Previous studies have used indices that relied on a comparison to reference sites, for example the number of a predefined pool of target species or compositional similarity. However, since restoration sites have rarely the same biotic and abiotic conditions as reference sites, plant communities in restored sites will not perfectly match the reference sites. Furthermore, such indices fail when reference sites are lacking or degraded. Hence, there is a need for an alternative approach that evaluates the conservation value of a restored site independently from reference sites. We propose that naturalness indicator values can be an option to measure restoration success. The approach of using naturalness indicator values makes use of the fact that plants are able to indicate environmental parameters, including degradation and regeneration. We compared and measured the restoration success of three well-established methods for grassland restoration (sod transplantation, hay transfer, seeding) with three commonly used indices (diversity, number of target species, similarity to reference sites). The results verified earlier studies and showed that sod transplantation led to the highest restoration success followed by hay transfer and seeding of sitespecific seed mixtures. Further, we used those well-established indices for an evaluation of novel, naturalness-based indices (unweighted and cover-weighted mean naturalness indicator values, the sum of naturalness indicator values). While calculating the means of naturalness indicator values failed to offer conclusive information on restoration success, we could show that the sum of naturalness indicator values was highly correlated with the number of target species and compositional similarity to reference sites. Thus, our case study demonstrated that naturalness indices can be an excellent option to estimate success in grassland restoration.