Profiteers of environmental change in the Swiss Alps: increase of thermophilous and generalist plants in wetland ecosystems within the last 10years

It has been predicted that Europe will experience a rise in temperature of 2.2-5.3°C within this century. This increase in temperature may lead to vegetation change along altitudinal gradients. To test whether vegetation composition has already changed in the recent decade due to current warming (and other concomitant environmental changes), we recorded plant species composition in 1995 and 2005/2006 in Swiss pre-alpine fen meadows (800-1,400ma.s.l.). Despite no obvious changes in the management of these fens, overall, plant species richness (cumulative number of plant species at five plots per site) significantly increased over this period. This was mainly due to an increase in the number of thermophilous, rich-soil-indicator and shade-indicator species, which corresponded to increased community productivity and shading within the vegetation layer. In contrast, fen specialists significantly declined in species numbers. The strongest species shifts occurred at the lowest sites, which overall had a higher colonization rate by new species than did sites at higher altitudes. Vegetation change along the altitudinal gradient was also affected by different types of land management: early-flowering species and species with low habitat specificity had high colonization rates in grazed fens, especially at low altitude

Density-Independent Mortality and Increasing Plant Diversity Are Associated with Differentiation of Taraxacum officinale into r- and K-Strategists

Background: Differential selection between clones of apomictic species may result in ecological differentiation without mutation and recombination, thus offering a simple system to study adaptation and life-history evolution in plants. Methodology/Principal Findings: We caused density-independent mortality by weeding to colonizer populations of the largely apomictic Taraxacum officinale (Asteraceae) over a 5-year period in a grassland biodiversity experiment (Jena Experiment). We compared the offspring of colonizer populations with resident populations deliberately sown into similar communities. Plants raised from cuttings and seeds of colonizer and resident populations were grown under uniform conditions. Offspring from colonizer populations had higher reproductive output, which was in general agreement with predictions of r-selection theory. Offspring from resident populations had higher root and leaf biomass, fewer flower heads and higher individual seed mass as predicted under K-selection. Plants grown from cuttings and seeds differed to some degree in the strength, but not in the direction, of their response to the r- vs. K-selection regime. More diverse communities appeared to exert stronger K-selection on resident populations in plants grown from cuttings, while we did not find significant effects of increasing species richness on plants grown from seeds. Conclusions/Significance: Differentiation into r- and K-strategists suggests that clones with characteristics of r-strategists were selected in regularly weeded plots through rapid colonization, while increasing plant diversity favoured the selection of clones with characteristics of K-strategists in resident populations. Our results show that different selection pressures may result in a rapid genetic differentiation within a largely apomictic species. Even under the assumption that colonizer and resident populations, respectively, happened to be r- vs. K-selected already at the start of the experiment, our results still indicate that the association of these strategies with the corresponding selection regimes was maintained during the 5-year experimental period

Relationship between Reproductive Allocation and Relative Abundance among 32 Species of a Tibetan Alpine Meadow: Effects of Fertilization and Grazing

Background: Understanding the relationship between species traits and species abundance is an important goal in ecology and biodiversity science. Although theoretical studies predict that traits related to performance (e.g. reproductive allocation) are most directly linked to species abundance within a community, empirical investigations have rarely been done. It also remains unclear how environmental factors such as grazing or fertilizer application affect the predicted relationship. Methodology: We conducted a 3-year field experiment in a Tibetan alpine meadow to assess the relationship between plant reproductive allocation (RA) and species relative abundance (SRA) on control, grazed and fertilized plots. Overall, the studied plant community contained 32 common species. Principal Findings: At the treatment level, (i) RA was negatively correlated with SRA on control plots and during the first year on fertilized plots. (ii) No negative RA–SRA correlations were observed on grazed plots and during the second and third year on fertilized plots. (iii) Seed size was positively correlated with SRA on control plots. At the plot level, the correlation between SRA and RA were not affected by treatment, year or species composition. Conclusions/Significance: Our study shows that the performance-related trait RA can negatively affect SRA within communities, which is possibly due to the tradeoffs between clonal growth (for space occupancy) and sexual reproduction. We propose that if different species occupy different positions along these tradeoffs it will contribute to biodiversity maintenance in local communities or even at lager scale

Effects of landsacape characteristics on fragmented wetland plant communities and experimental metapopulations of Arabidopsis thaliana

This study focused on the effects of landscape patterns (habitat fragmentation and spatial structure) and landscape dynamics (changes in landscape patterns through time) on plant communities, using both observational and experimental approaches, at different scales from natural landscapes to experimental microcosms

Applying Circuitscape Theory to Identify Migration Corridors Between Mooteh and Ghamishloo Wildlife Refuges in Isfahan Province-Iran

Modeling of ecological connectivity across landscape is important for understanding a wide range of ecological processes. Modeling ecological connectivity between habitats and incorporating these models into conservation planning require quantifying the effect of spatial patterns of landscape on the degree of habitats connectivity. Recently, concepts from electrical circuit theory have been adapted to model habitats connectivity, predict patterns of movement and identifying corridors. Circuits are defined as network of nodes connected by resistors (electrical components that conduct current).the application of circuit theory to ecological problems is because of connections between ecological and electrical connectivity: as multiple or wider conductors connecting two electrical nodes (in parallel) allow greater current flow than would a single, narrow conductor, multiple or wider habitat swaths connecting populations or habitats also allow greater movement between them.. This theory treats landscape as a conductive surface and creates a network by converting pixels to nodes and connecting them to their immediate neighbors. Results of this theory are current and voltage maps, which can be related to ecological processes like individual movements. In this study circuit theory was applied to evaluate habitats connectivity for Persian gazella (Gazella subgutturosa) and Isfahan wild sheep (Ovis omon isfahanica) between Mooteh and Ghamishloo wildlife refuges in Isfahan province-Iran. Based on current maps, movement patterns and, functional connectivity for target species was evaluated .furthermore, area important for connectivity across the study area was identified

Analysis of Land Cover Changes in the Central Part of Isfahan (Iran) Using Landscape Metrics

Knowledge about long-term land cover/use changes is essential for evaluating and predicting their consequent problems by urban managers and policymakers. Remote sensing with landscape metrics is an effective tool for monitoring these changes in urban cores and their peripheral areas. During the recent decades, industrial and urban growth, and immigration of people into Isfahan metropolitan area (Iran) have affected its surrounding environment. The objective of this research was to quantify the changes of landscape patterns in the center of Isfahan during the last two decades. For monitoring spatial pattern changes, land use and cover maps of the area were prepared using supervised maximum likelihood classification of Landsat Thematic Mapper (TM) images taken in 1990 and 2010. In order to quantify the changes in landscape patterns during this period, we used several landscape metrics of each class type and total landscape. These metrics included percentage of landscape (PLAND), number of patches (NP), mean patch size (MPS), patch density (PD), largest patch index (LPI), mean nearest neighbor (MNN), contagion (CONTAG), and Shannon’s diversity index (SHDI). The results of this study showed that the proportion of urban area and bare land significantly increased during the study period. Decreased mean patch area for agriculture and undeveloped land uses indicated that the landscape had been more fragmented in these two classes. The synoptic analysis of selected metrics for landscape level indicated that the metric values of MNNand SHDI to have increased and the metric values of LPI has reduced during the last two decades

Quantifying Landscape Spatial Pattern Changes in the Caucasian Black Grouse (Tetrao mlokosiewiczi) Habitat in Arasbaran Biosphere Reserve

Large scale land use/cover changes and habitat fragmentation have been associated with the decline of many wildlife populations in ecological sensitive regions. The main goal of this study was to quantify the spatial pattern changes in Caucasian Black Grouse habitat in Arasbaran Biosphere Reserve, Northwest of Iran in a period of 24 years (1987–2011). Caucasian black grouse (Tetrao mlokosiewiczi) in Iran is restricted to the Arasbaran area, and the populations and range of this specialist bird species have been declining over the last decades. This study focuses on the landscape structure changes of black grouse habitat in Arasbaran Biosphere reserve. We used Landsat Thematic Mapper (TM) satellite images from 1987 and 2011, and ETM+ from 2001, for analysis of the spatial patterns of land use/cover patches. The satellite images were geometrically corrected and classified. For quantifying landscape pattern changes, various landscape metrics were derived from spatial analysis software FRAGSTATS, including NP (Number of Patches), LPI (Largest Patch Index) and TE (Total Edge). The results indicated that the proportion of forest was significantly decreased from 39.95% to 31.95%, and proportion of grassland was decreased from 44.45% to 38.44% during the last 24 years, while proportion of dominated by astragalus was increased from 3.30% to 15.65%. Total Edge (TE) was decreased 8000 meters at altitude over 1800 meters. Our result provided quantitative data on habitat loss and landscape fragmentation in Arasbaran Biosphere reserve and indicated negative impacts of the landscape structure changes on Black grouse habitat

Assessment of the Conservation Status and Habitat Suitability of Critically Endangered Lorestan Newt (Neurergus Kaiseri) in Lorestan and Khuzestan Provinces

Lorestan newt (Neurergus kaiseri) is an endemic species which has restricted dispersal in southern Zagros Mountains in Iran, and it is listed as critically endangered in IUCN red list. Today the populations of this species are decreasing and facing serious threats. In this study, habitat suitability of Neurergus kaiseri was evaluated using a MaxEnt modelling approach according to environmental and climatic parameters (thermal and precipitation). Based on the results derived from the MaxEnt model, the most important parameters were related to annual and seasonality precipitation, annual mean temperature, elevation and land cover, respectively. Also, assessment of the conservation status of this species with species distribution areas and adapting them with protection networks revealed that currently, none of the suitable habitats of Lorestan newt are protected and there is no legal support for conserving these sites that the issue makes this critically endangered species even more vulnerable