Montane Heathland Research Articles

Resistance of soil bacterial communities from montane heathland ecosystems in the Cantabrian mountains (NW Spain) to a gradient of experimental nitrogen deposition

Elevated atmospheric nitrogen (N) deposition on terrestrial ecosystems has become one of the most important drivers of microbial diversity loss on a global scale, and has been reported to alter the soil function of nutrient-poor, montane Calluna vulgaris heathlands in the context of global change. In this work we analyze for the first time the shifts of bacterial communities in response to experimental addition of N in Calluna heathlands as a simulation of atmospheric deposition. Specifically, we evaluated the effects of five N addition treatments (0, 10, 20, and 50 kg N ha−1 yr−1 for 3-years; and 56 kg N ha−1 yr−1 for 10-years) on the resistance of soil bacterial communities as determined by changes in their composition and alpha and beta diversities. The study was conducted in montane Calluna heathlands at different development stages (young and mature phases) in the southern side of the Cantabrian Mountains (NW Spain). Our results evidenced a substantial increase of long-term (10-years) N inputs on soil extractable N-NH4+, particularly in young Calluna stands. The alpha diversity of soil bacterial communities in mature Calluna stands did not show a significant response to experimental N addition, whereas it was significantly higher under long-term chronic N addition (56 kg N ha−1 yr−1 for 10-years) in young Calluna stands. These bacterial community shifts are mainly attributable to a decrease in the dominance of Acidobacteria phylum, the most representative in montane Calluna ecosystems, in favor of copiotrophic taxa such as Actinobacteria or Proteobacteria phyla, favored under increased N availability. Future research should investigate what specific ecosystem functions performed by soil bacterial communities may be sensitive to increased nitrogen depositions, which may have substantial implications for the understanding of montane Calluna ecosystems' stability.

Disturbance and biomass removal enhance population reinforcement of a plant species of European conservation concern

ABSTRACT Background Arnica montana is a threatened plant species that highly depends on species-specific conservation action. Aims We conducted three experiments in montane heathlands to quantify the role of disturbance for population reinforcement of A. montana. Methods In the first experiment, clusters of A. montana were raked to remove biomass and promote vegetative growth. In two other experiments, we analysed what kind of disturbance intensity is necessary to promote the establishment of A. montana by seeding and planting, respectively. Different traits with respect to population structure and growth of A. montana (e.g. abundance of rosettes and flowering stems) were measured. Results Raking resulted in the removal of bryophytes and parts of the herb layer and strongly fostered vegetative reproduction of A. montana. In general, disturbance enhanced the establishment of A. montana by seeding, however, the establishment rate was low. By contrast, planting of A. montana in plots whose surface was disturbed greatly increased the populations of A. montana. Conclusion Our study highlights that populations of A. montana much depend for re­production on the disturbance of the above-ground vegetation. We identified (i) disturbance of vegetation within existing populations for fostering vegetative reproduction and (ii) planting of A. montana in previously disturbed vegetation as the most suitable measures for reinforcing populations of this species of European conservation concern.

Rejuvenation and restoration measures foster specialised and threatened carabid beetle species in montane heathland ecosystems

Abstract Montane heathlands are among the most threatened semi‐natural ecosystems across Central Europe. Nevertheless, empirical studies on the effects of rejuvenation and restoration of montane heathlands have been scarce thus far. The aim of our study was to analyse the long‐term effects of heathland rejuvenation and restoration on carabid beetle assemblages. Our study took place in the Rothaar Mountains, one of the most important strongholds of montane heathlands in Central Europe. We considered four different successional stages: (i) early‐successional heathlands as a result of rejuvenation measures (EARLY), (ii) restored heathlands (RESTORED), (iii) late‐successional heathlands (LATE) and (iv) windthrows (WIND). Our study revealed that the composition of carabid beetle assemblages differed across the gradient. From the earlier to the later stages, beetle biomass, richness of macropterous, threatened and heathland species decreased, whereas moisture and shading indicator values increased. The number of indicator species peaked in EARLY and RESTORED. Solely brachypterous species had the highest species richness in the later seral stages. Overall, rejuvenation and restoration measures fostered specialised and threatened carabid beetle species of montane heathlands. In contrast, carabid beetle assemblages of the two later and dense successional stages consisted mainly of non‐threatened habitat generalists. Vegetation structure and the interrelated microclimate are assumed to be the key drivers of assemblage composition. For the long‐term conservation of montane heathlands and their specialised carabid beetle assemblages, we recommend rejuvenation by sod cutting and choppering in a mosaic‐like manner and at intervals that clearly exceed more than two decades.

Restoration of montane heathlands – Early- and mid-successional stages promote phytodiversity

Heathlands are highly threatened ecosystems with high conservation value. Montane heathlands have suffered from widespread habitat loss due to land-use abandonment and afforestation. The aim of our study was to analyse the long-term effects of montane heathland restoration, nine to ten years after restoration, on vegetation in the Rothaar Mountains (Central Germany). We compared vegetation composition in four vegetation types: (i) early-successional heathland stages on sod cut sites or ski pistes (hereafter referred to as EARLY), (ii) late-successional (old-growth) heathland stages (LATE), (iii) restored heathlands on former spruce forests where seed transfer by hydroseeding or the application of chopper material (crushed aboveground biomass from donor heathland site including seeds) had been applied (RESTORED) and (iv) windthrows with salvage logging (WIND). In every vegetation type, ten vegetation relevés were carried out and the cover of all vascular plant, bryophyte and terricolous lichen species were analysed. Furthermore, soil samples were taken in every relevé and measured with respect to soil acidity as well as carbon, nitrogen, phosphate and potassium contents.Our study demonstrated that the restoration plots were characterised by chemical soil conditions comparable to those of existing heathland communities. RESTORED was the hotspot of phytodiversity. Species richness of vascular plants, threatened vascular plants and target species peaked on RESTORED, followed by EARLY. Additionally, EARLY was characterised by the highest number of terricolous lichen species and threatened bryophyte species.The applied restoration measures were successful in establishing montane-heathland and acidic-grassland vegetation on former spruce forests. However, two usually dominant species of montane heathlands, Vaccinium myrtillus and Vaccinium vitis-idaea, had hardly established. Both species are slow colonisers and require specific microsites characterised by high moisture and organic content of the soil for generative reproduction. Additionally, the study demonstrated that early- to mid-successional stages of montane heathlands play a vital role for the conservation of cryptogams and low-competitive plant species.

Effects of montane heathland rejuvenation on phytodiversity depend on management intensity and succession

Heathlands are of high importance for biodiversity conservation, and most heathlands depend on management. While the effects of management on biodiversity are well-studied for lowland heathlands, studies on Central European montane heathlands are scarce. Therefore, we analysed the effects of heathland rejuvenation measures on soil characteristics and phytodiversity within Central European montane heathlands. We focused on four heathland types: sod-cut heathlands with (i) early-successional stages (SOD CUT-EARLY) and (ii) mid-successional stages (SOD CUT-MID), (iii) choppered heathlands with mid-successional stages (CHOP-MID) and (iv) late-successional heathland stages (CONTROL). For every heathland type, ten vegetation relevés were carried out. In every relevé, we analysed the cover of all vascular plant, bryophyte and terricolous lichen species. Additionally, soil characteristics were measured. Statistical analyses included generalised linear mixed-effects models and non-metric multidimensional scaling.Our study revealed that rejuvenation of montane heathlands reduced soil nutrient levels, increased pH values and had positive effects on phytodiversity. The effects of rejuvenation were persistent. Even after around 20 years following the measures, SOD CUT-MID and CHOP-MID were characterised by lower nutrient levels and different plant assemblages compared to CONTROL.Sod cutting and choppering promoted the rejuvenation of Calluna vulgaris, one target species of montane heathlands. However, the regeneration of Vaccinium vitis-idaea – another ericaceous target species – was clearly favoured by choppering in comparison to sod cutting. By contrast, overall vascular plant species diversity as well as the number of threatened vascular plant and target species were favoured by sod cutting in the long run while early-successional stages after sod cutting had positive effects on lichen diversity. Due to the contrary effects of the two rejuvenation measures, we recommend a spatial mix of high-intensity (sod cutting) and less intensive (choppering) rejuvenation methods in montane heathlands.

Time- and age-related effects of experimentally simulated nitrogen deposition on the functioning of montane heathland ecosystems

Ecosystems adapted to low nitrogen (N) conditions such as Calluna-heathlands are especially sensitive to enhanced atmospheric N deposition that affects many aspects of ecosystem functioning like nutrient cycling, soil properties and plant-microbial-enzyme relationships. We investigated the effects of five levels of experimentally-simulated N deposition rates (i.e., N fertilization treatments: 0, 10, 20 and 50kgNha−1yr−1 for 3years, and 56kgNha−1yr−1 for 10years) on: plant, litter, microbial biomass and soil nutrient contents, soil extracellular enzymatic activities, and plant root ericoid mycorrhizal colonization. The study was conducted in marginal montane Calluna-heathlands at different developmental stages resulting from management (young/building-phase and mature-phase). Our findings revealed that many soil properties did not show a statistically significant response to the experimental addition of N, including: total N, organic carbon (C), C:N ratio, extractable N-NO3−, available phosphorus (P), urease and β-glucosidase enzyme activities, and microbial biomass C and N. Our results also evidenced a considerable positive impact of chronic (10-year) high-N loading on soil extractable N-NH4+, acid phosphatase enzyme activity, Calluna root mycorrhizal colonization by ericoid fungi, Calluna shoot N and P contents, and litter N content and N:P ratio. The age of heathland vegetation influenced the effects of N addition on ericoid mycorrhizal colonization, resulting in higher colonized roots in young heathlands at the control, low and medium N-input rates; and in mature ones at the high and chronically high N rates. Also, young heathlands exhibited greater soil extractable N-NO3−, available P, microbial biomass N, Calluna shoot N and P contents, and litter N content, compared to mature ones. Our results highlighted that accounting for the N-input load and duration, as well as the developmental stage of the vegetation, is important for assessing the effects of added N, particularly at the heathlands' southern distribution limit.

Monitoring protected areas from space: A multi-temporalassessment using raptors as biodiversity surrogates.

Monitoring protected areas (PAs) is essential for systematic evaluation of their effectiveness in terms of habitat protection, preservation and representativeness. This study illustrates how the use of species distribution models that combine remote sensing data and information about biodiversity surrogates can contribute to develop a systematic protocol for monitoring PAs. In particular, we assessed the effectiveness of the Natura 2000 (N2000) network, for conserving and preserving the representativeness of seven raptor species in a highly-dynamic landscape in northwest Spain between 2001 and 2014. We also evaluated the cost-effectiveness of the N2000 network by using the total area under protection as a proxy for conservation costs. Overall, the N2000 network was found to poorly represent the habitats of the raptor species. Despite the low representativeness, this network showed a high degree of effectiveness due to increased overall habitat availability for generalist and forest specialist species between 2001 and 2014. Nevertheless, additional protected areas should be established in the near future to increase their representativeness, and thus ensure the protection of open-habitat specialist species and their priority habitats. In addition, proactive conservation measures in natural and semi-natural ecosystems (in particular, montane heathlands) will be essential for long-term protection of Montagu’s harrier (species listed in the Annex I of the Bird Directive), and thus complying with the current European Environmental Legislation. This study sheds light on how the development and application of new protected area indices based on the combined use of freely-available satellite data and species distribution models may contribute substantially to the cost-efficiency of the PA monitoring systems, and to the ‘Fitness Check’ process of EU Nature Directives.

From deforestation to blossom – Large-scale restoration of montane heathland vegetation

Land-use change and atmospheric nitrogen deposition have negatively affected heathlands with severe consequences for biodiversity. One possible way to counteract these negative impacts can be habitat restoration. The aim of this study was to evaluate the success of montane heathland restoration on former spruce forests using vascular plants as indicators. We compared the three following land-use types (i) grazed montane heathlands, (ii) grazed restoration sites on former spruce forests where seed transfer has been applied, and (iii) ungrazed clear-cuts of spruce forests.Four to five years after restoration each land-use type was according to an indicator species analysis characterised by different indicator species. Despite the short time period since the implementation of the restoration measures and many similarities in plant species assemblages between restoration and clear-cut sites, Calluna vulgaris had vigorously established on restoration sites with a mean cover of nearly 20%, whereas it was largely absent at clear-cut sites. In addition, there was a clear trend that plant assemblages of restoration and clear-cut sites become more clearly separated. The cover of non-target species significantly increased at clear-cut sites and the cover of C. vulgaris remained extremely low.The conducted restoration measures are able to initiate the establishment of typical montane heathland vegetation on former spruce forests. However, restoration of the complete plant assemblage would require additional sod transplantation as both Vaccinium myrtillus and V. vitis-idaea mainly depend on vegetative regeneration. Furthermore, topsoil removal of the most nutrient-rich parts would be necessary to counteract the encroachment of Cytisus scoparius.

Experimental evidence from Cantabrian mountain heathlands suggests new recommendations for management of Vaccinium myrtillus L

Background: Management actions in mountain heathlands oriented to increasing the cover of Vaccinium myrtillus promote mowing of Calluna vulgaris to avoid competition. However, such action ignores the fact that plant–plant interactions range from competition to facilitation under different stress conditions.Aims: To test whether the interactions between these two species are related to competition or facilitation, which would change the perspective for their management in mountain heathlands.Methods: A total of 40 experimental plots located in a montane heathland (northern Spain) were selected. Calluna or Vaccinium plants were either cut at ground level or not cut, and plots were fertilized with nitrogen or not in a three-factorial design. Vegetative and reproductive shoot mass and length of the current year’s shoots were estimated in two consecutive years for both species. Herbivory on Vaccinium by browsing ungulates was compared in control plots and plots where Calluna had been cut 2 yrs ago.Results: The two study species co-occurred in 72.4% of the sampled plots, although Calluna was more abundant. Vaccinium growth was greater in plots with Calluna than in plots where Calluna had been cut. Browsing on Vaccinium was also higher in plots were Calluna had been cut, and the effect of fertilization was only significant on the reproductive biomass of Calluna.Conclusions: Contrary to initial proposals, our results suggest that Vaccinium does not always benefit from the cutting of Calluna in heathlands. Thus, the management of Cantabrian mountain heathlands should consider maintaining Calluna in order to facilitate the growth of Vaccinium.

Montane heathland rejuvenation by choppering—Effects on vascular plant and arthropod assemblages

Land-use changes and atmospheric nitrogen deposition have negatively affected heathland biota. Active habitat management is one possible way of counteracting the biodiversity loss associated with these habitat alterations. However, management practices for lowland heathlands often have been transferred to montane heathlands, irrespective of the differences in environmental conditions or assemblage composition. The objective of this study was to evaluate the effects of so-called choppering for the rejuvenation of montane heathland. Choppering involves chaffing and removing the largest part of the organic layer down to the mineral soil. In this study, we compared montane heathlands that were rejuvenated through the application of choppering (CHOPPER) to old-growth montane heathlands (CONTROL). Thirteen years after the rejuvenation measures had been conducted, the environmental conditions between CHOPPER and CONTROL still differed. CHOPPER was characterised by shorter vegetation (herbs/grasses and dwarf shrubs), more bare soil, less litter and higher temperatures. Although, the vascular plants and all studied arthropod groups were affected by the environmental changes, their responses were somewhat different. CHOPPER had a unique assemblage of each taxonomic group that included at least a few heathland species that mainly occurred in this treatment. However, choppering was most beneficial for vascular plants, grasshoppers and carabid beetles. As shown for lowland heathlands, choppering is also a suitable management measure for montane heathland to rejuvenate vegetation with its characteristic arthropod fauna. Due to the intact seed banks and Ericaceae root systems with their mycorrhizas, in combination with the availability of bare soil, heathland vegetation can rapidly regenerate after choppering. The keystone structures that explain the high relevance of CHOPPER, especially for vascular plants, grasshoppers and carabid beetles, are low-growing vegetation and bare soil, which result in light and warm microclimatic conditions. Based on the results of our study, we recommend choppering as a regular management measure to rejuvenate montane heathland.

Carabid beetles and spiders as bioindicators for the evaluation of montane heathland restoration on former spruce forests

Semi-natural habitats such as heathland ecosystems are important for the conservation of biodiversity. Due to land use changes, these valuable ecosystems have become highly threatened. Nowadays, their management and restoration is of special relevance for nature conservation.In this study, we used carabid beetles and spiders as bioindicators to evaluate the success of montane heathland restoration on former spruce forests. We compared three different treatments: (i) montane heathlands (MONHEATH), (ii) restoration (RESSITE) and (iii) control (CONTROL) sites.Four to five years after conducting the restoration measures, all environmental variables, except soil moisture, significantly differed between MONHEATH on one hand and RESSITE and CONTROL on the other. MONHEATH was characterised by a high cover of dwarf shrubs; in contrast, RESSITE/CONTROL had a vegetation rich in herbs/grasses with some bare ground. Both carabid beetle and spider assemblage composition clearly reflected these differences in environmental conditions. Alpha-diversity (Simpson diversity, evenness) and niche positions were, however, only significantly different for spiders. Diversity as well as spider indicator values for shade and moisture were higher for MONHEATH.Due to the cool and wet montane climate and the dense dwarf-shrub stands the carabid beetle and spider species characteristic of MONHEATH are typical woodland species. Four to five years after restoration, RESSITE and CONTROL still represent early successional stages with a low cover of the Ericaceae target dwarf shrubs (Calluna vulgaris, Vaccinium myrtillus and Vaccinium vitis-idaea), but are already home to some typical heathland carabid beetle and spider species that are missing in MONHEATH.

Effects of Montane Heathland Restoration on Leafhopper Assemblages (Insecta: Auchenorrhyncha)

AbstractAt the beginning of the 20th century, many montane heathlands were abandoned and became subject to natural succession or afforestation by humans. Thus, the formerly large montane heathlands slowly degraded into small and isolated patches. In this study, we evaluate the influence of restoration measures on leafhopper (Auchenorrhyncha) assemblages of montane heathland ecosystems in Central Europe. Our analyses comprised three different site types that were adjacent to each other: (1) montane heathlands, (2) restoration sites, and (3) control sites. Leafhoppers showed a clear response to montane heathland restoration. Thus, after 4–5 years since implementation of restoration measurements restoration sites were characterized by the highest species richness. However, detailed analyses of leafhopper diversity, species composition, and environmental parameters on the three site types revealed that restoration sites were rather similar to control sites and significantly differing from montane heathlands. We conclude that leafhoppers are excellent bioindicators for restoration measurements because they reflected environmental differences between the three site types. Restoration measurements might only be a useful instrument to promote typical montane heathland leafhopper communities in the long run. Colonization by leafhoppers is, however, dependent on many different factors such as leafhopper mobility, vegetation structure, microclimate, and the establishment of ericaceous dwarf shrubs. Practitioners should establish a management regime (grazing and sod‐cutting) that creates a mosaic of different habitat structures and increases typical heathland vegetation, thus, favoring the colonization of typical heathland leafhoppers.

Relationships between time since fire and honeyeater abundance in montane heathland

Montane heath communities in south-eastern Australia provide a valuable nectar resource for honeyeaters (Meliphagidae) but are subject to variable fire regimes that may influence the production of this resource and the abundance of honeyeaters. Little is known about changes in honeyeater communities through time after fire. We examined seasonal relationships between characteristics of the honeyeater community and time since fire in Blue Mountains Heath using regression analysis. Positive trends were expected, with possible eventual declines owing to senescence of the vegetation community. Twelve sites ranging from 2 to 39 years since fire were sampled in late winter-spring (cool season) and in late summer (warm season). In the warm season, abundance of all honeyeaters and abundance of New Holland Honeyeaters showed saturation relationships with time since fire. A steep rate of increase in abundance reached a plateau 10 years after fire for all honeyeaters and New Holland Honeyeaters. In the cool season, New Holland Honeyeater abundance was positively influenced by time since fire. This study showed that honeyeaters used heath across a broad range of post-fire intervals >10 years and there was no evidence of a decline as the heath matured (to 39 years post-fire). Our research has contributed to the understanding of the links between fire ecology and avian habitat use, which in turn provides a scientific basis for ecologically sustainable fire management of natural areas.

Rapid response of Orthoptera to restoration of montane heathland

Understanding how to restore threatened ecosystems is of special relevance for nature conservation. The aim of this study was to use Orthoptera as ecological indicators for the effects of montane heathland restoration in Central Europe. We analysed the three following treatments: (i) montane heathlands (MONHEATH) (N = 7), (ii) restoration sites (RESSITE) (N = 3) and (iii) clear-cuts of spruce forests as unprocessed and ungrazed control sites (CONTROL) (N = 3). Vegetation structure and microclimate differed considerably between MONHEATH on the one hand and RESSITE and CONTROL on the other hand. Orthoptera species richness and density did so too. MONHEATH was characterised by a high-growing dense dwarf-shrub and moss layer having a cool microclimate and high soil moisture. In contrast, RESSITE and CONTROL had sparse vegetation and a warm microclimate; Orthoptera species richness and density was highest on these sites. Our study clearly showed that heathland Orthoptera responded rapidly to restoration measures, while Ericaceae dwarf shrubs slowly established. The vast majority of Orthoptera species found on the restoration sites are early and mid-successional species. The colonization of the sites by late-successional Orthoptera species in the future will depend on the further development of the heathland vegetation; that is, if Ericaceae will expand to the sites. We conclude that the realised restoration measures are suitable to promote heathland Orthoptera of early and mid-successional stages. However, the current management of montane heathlands is insufficient and needs to be intensified in order to provide structurally diverse habitats with their characteristic orthopteran assemblages.

Tending for Cattle: Traditional Fire Management in Ethiopian Montane Heathlands

Johansson, M. U., M. Fetene, A. Malmer, and A. Granström. 2012. Tending for cattle: traditional fire management in Ethiopian montane heathlands. Ecology and Society 17(3): 19. https://doi.org/10.5751/ES-04881-170319

Species interaction and response to wind speed alter the impact of projected temperature change in a montane ecosystem

Question: How does an improved understanding of species interactions, combined with an additional ecological variable (wind speed), alter the projected vegetation response to variation in altitudinal temperature? Location: Cairngorm Mountains, Scotland. Methods: Montane heathland vegetation was sampled from 144 plots (432 quadrats) comprising eight altitudinal transects. Ordination by partial DCA and path analysis was used to confirm: (1) the effect of wind speed and altitude (≈ temperature) on vegetation structure, i.e. canopy height and cover of bare ground, and (2) the control of arctic/alpine macrolichen occurrence by vegetation structure. Nested regression analysis was used to project the response of vegetation structure and lichen occurrence to temperature change scenarios with and without a step-wise change in future wind speed. Results: Warming trends shifted vegetation zones upwards, with a subsequent loss of suitable habitat for arctic/alpine lichens. However, incorporating wind speed as an additional explanatory variable had an important modifying effect on the vegetation response to temperature: decreasing wind speed exaggerates the effects of increased temperature and vice versa. Our models suggest that for the wind-driven heath examined, a 20% increase in mean wind speed may negate the effect of increased temperature on vegetation structure, resulting in no net change in lichen occurrence. Conclusions: We caution that an improved understanding of species interactions in vegetation response models may force the consideration of locally variable environmental parameters (e.g. wind speed), bringing into question the predicted vegetation response based on standard projections of temperature change along altitudinal gradients.

Prolonged frost increases release of C and N from a montane heathland soil in southern Norway

Montane heathlands of southern Norway are important contributors of carbon (C) and nitrogen (N) to aquatic and marine systems. Climate change may give milder winters and decreasing snow cover, producing pronounced soil temperature variations, including freeze-thaw events. A controlled experiment in the laboratory was set up to investigate the effects of freeze-thaw on C and N release. Undisturbed soil columns were subjected to different temperature regimes, including freeze-thaw cycles and one permanent frost program. Leachates after permanent frost had a significant increase in DOC, DON and NH 4-N concentrations. Slow temperature cycling with soil temperature periodically well below 0 had a similar, but far less pronounced effect on leachate composition. On the other hand, the effect of fast temperature cycling, with soil temperature periodically slightly below 0, was not significantly different from the permanent thaw treatment. Permanent frost, and to some extent slow cycling, caused a significant decrease in NO 3-N concentration, and generally gave increased levels of organic relative to inorganic C and N species. Our data suggest that at realistic temperatures, only prolonged soil frost induces pronounced effects on C and N release.

Manipulation of Snow in Small Headwater Catchments at Storgama, Norway: Effects on Leaching of Inorganic Nitrogen

We have manipulated the winter-time soil temperature regime of small headwater catchments in a montane heathland area of southern Norway to study the possible effects on concentrations and fluxes of inorganic nitrogen in runoff. The experiments included extra insulation of soils in two catchments to prevent subzero temperatures during winter, and removal of snow in two other catchments to promote soil frost. Increased soil temperatures during winter increased the springtime concentrations and fluxes of ammonium (NH4) and nitrate (NO3) in runoff. By contrast, snow removal with development of significant soil frost showed no systematic effects on mean concentrations or fluxes of inorganic N. The results from our experiments suggest that warmer soils during winter caused by exceptionally mild winters, or alternatively a heavy snowpack, imply a greater risk for inorganic N leaching in this region than a possible increase of soil frost events because of reduced snow cover.

Manipulation of Snow in Small Headwater Catchments at Storgama, Norway: Effects on Leaching of Total Organic Carbon and Total Organic Nitrogen

Projected increases in winter temperature due to future climate change may cause decreased snow accumulation at lower and intermediate altitudes in northern temperate regions. The resulting changes in soil temperature and water regime may affect the leaching of total organic carbon (TOC) and total organic nitrogen (TON). We manipulated the snow cover of small headwater catchments in a montane heathland area of southern Norway to quantify its effect on concentrations and fluxes of TOC and TON in runoff. Manipulations included snow removal, to promote soil frost, and insulation, to prevent soil frost. Snow removal resulted in increased TOC and TON concentrations, but decreased fluxes. Insulation caused a slight decrease in concentrations and fluxes of TOC. Our experiments show that a change in snow depth, and thus soil temperature, is not likely to have serious effects on TOC and TON leaching in the montane heathland area studied.

Montane Amphibian and Reptile Communities in Madagascar

Abstract; Two habitats in Madagascar, secondary, montane heathland and high plateau prairie, are considered artificial, having been created by human‐set fires soon after the island was colonized less than 2000 years ago. These prairie and secondary heathland habitats are also thought to be degraded and faunistically depauperate. To test the depauperate fauna hypothesis we measured levels of herpetofaunal (amphibian and reptile) endemicity between primary forest, montane secondary heathland, and high plateau prairie. We found no species endemic to high plateau prairie, but a significant percentage of the montane herpetofauna is restricted to post‐fire secondary heathland. These results support the human‐origin hypothesis for prairie, but secondary heathland appears to be a natural, post‐fire successional stage that leads to a climax of sclero‐phyllous forest. This suggests that careful management of montane heathland could establish new dispersal corridors between currently isolated montane forest blocks and, therefore, could offer new opportunities for conservation in Madagascar. Despite widespread burning, the montane heathlands of Madagascar have diverse herpetofaunal communities, demonstrating that these montane communities are not as seriously degraded as previously believed, and that they may be naturally resistant to fire.