Open Moorland Research Articles

Novice gyrfalcons cut straight to the kill on maiden flight

Prized for their rarity during the Middle Ages and designated the bird of kings by medieval gentlemen, gyrfalcons may even have instigated the downfall of a Chinese empire, thanks to its demand for the merciless hunters. Gyrfalcons carry a majestic cachet, yet it wasn't clear whether these masters of the air are unique or use the same interception strategy as other falcons when closing in for the kill; they rarely swoop from spectacular heights to intercept prey like their smaller cousin, the peregrine falcon. According to Caroline Brighton from the University of Oxford, UK, ‘Wild gyrfalcons are most often recorded performing low surprise attacks initiated from a perch or from ridge soaring’. Knowing that Harris’ hawks hound their victim from behind, Brighton and her colleagues, Katherine Chapman (University of Oxford), Nicholas Fox (Wingbeat Ltd) and Graham Taylor (University of Oxford) wondered whether gyrfalcons use a hawk-like strategy, where they directly follow every twist and turn of their prey, or apply their peregrine cousin's strategy, cutting the corner off their approach and aiming ahead of their prey to intercept it. Puzzled by the mystery of the regal raptors, the team decided to investigate how novice gyrfalcons that had never pursued prey before tackled the interception challenge.‘Nick breeds gyrfalcons for falconry and he invited us to watch the training flights of his latest cohort of juvenile birds at their training grounds’, says Brighton, who joined Fox and the rest of the team in the north of England for the young birds’ maiden flights. ‘Northumberland has large expanses of open moorland, much better suited for flying drones and falcons’, Brighton explains. With each bird hooded and perched on its handler's glove, a drone pilot moved into position upwind of the young gyrfalcon with a remote controlled aeroplane disguised as a crow, known as a Rocrow. As soon as the handler removed the hood, the gyrfalcon set off in pursuit of the fleeing crow robot. ‘The pilot flew the Rocrow through a series of evasive turns and the trial ended when the falcon either touched or grabbed it with its talons’, says Brighton. Filming 20 skirmishes while tracking the robot prey and birds’ manoeuvres in fine detail with GPS loggers, the researchers were able to recreate each airborne duel back in the lab. They then simulated a range of dog fight styles, from the peregrine falcon's interception approach to the Harris’ hawk's hot pursuit, to find out which strategy most closely replicated the gyrfalcons’ flight path.Analysing 111 s of the birds’ intricate flight paths as they hunted their quarry over 1127 m in total, Brighton and Taylor successfully reproduced the bird's manoeuvres by recreating a variant of the peregrine falcon's interception approach, resulting in the gyrfalcon's signature tail-chase strategy. However, the inexperienced gyrfalcons were not as nimble as the smaller peregrine falcons, turning more slowly and pursuing their quarry farther before grasping it with their talons. Brighton and Taylor suggest that although the gyrfalcon's strategy is less efficient than the peregrine's, the prolonged chase allows them to harry their wild prey to exhaustion.The fact that gyrfalcons on their maiden flights were able to perform such meticulous interceptions with no practice suggests that they inherit the ability and cut straight to the kill without having to learn from other birds. The team's discovery that the gyrfalcon's interception flight path has more in common with that of their peregrine falcon cousins also suggests that these attack behaviours may be characteristic of all falcons and were practised by the last ancestor that the two species had in common.

Bird and small mammal community composition and abundance in upland open habitats and early conifer forests

Anthropogenic land-use change, such as commercial afforestation, is a significant driver of shifts in ecological communities and species abundance. In this study, the consequences of afforestation of upland habitats for two distinct animal groups, birds and small mammals, were examined by comparing open moorland, early pre-thicket conifer forests (2–4 years post-replanting) and late pre-thicket conifer forests (6–8 years post-replanting) across 24 upland study sites in Ireland. Field data were collected using bird point counts, live trapping of small mammals and detailed vegetation surveys. A total of 17 bird species and four small mammal species were detected. Both groups showed contrasting patterns of abundance between moorland and pre-thicket forests, with bird density being higher in moorland, while small mammal abundance was higher in pre-thicket forests. Bird diversity was lowest in moorland and highest in late pre-thicket forests, while small mammal diversity was highest in moorland and lowest in late pre-thicket forests. Our study shows that afforestation can alter the abundance and community composition of bird and small mammal populations and that the consequences of land-use change associated with afforestation in upland areas vary across different taxa. Our findings have important implications for forest management practices and conservation of upland habitats and species.

INTERACTION BETWEEN DIRECT GEOREFERENCING, CONTROL POINT CONFIGURATION AND CAMERA SELF-CALIBRATION FOR RTK-BASED UAV PHOTOGRAMMETRY

Abstract. Unmanned Aerial Vehicles (UAV) are enjoying increasing popularity in the photogrammetric community. The Chinese supplier DJI is the market leader with about 70% of the global consumer UAV market. The Phantom model has been available for more than 10 years and its current version "RTK" is equipped with a 2-frequency GNSS receiver, as a basis for direct georeferencing of image flights, using RTK or PPK technologies.In the context of the paper, different case studies are investigated, which allow statements on the geometric accuracy of UAV image flights as well as on the self-calibration of the camera systems.In the first example, four DJI Phantom 4 RTK systems are examined, which were flown in a cross flight pattern configuration on the area of the UAV test field "Zeche Zollern" in Dortmund, Germany. The second example analyses the results of an open moorland area where the establishment of GCPs is extremely difficult and expensive, hence direct georeferencing offers a promising way to evaluate deformations, soil movements or mass calculations. In this example a DJI Matrice 210 v2 RTK drone has been used and the results of two different software packages (Agisoft Metashape and RealityCapture) are analysed. The third example presents a reference building that has been established by the Lower Saxony administration for geoinformation in order to evaluate UAV photogrammetry for cadastral purposes. Here again a DJI Phantom 4 RTK has been tested in a variety of flight configurations and a large number of high precision ground control and check points.The case studies show that the RTK option leads to sufficient results if at least 1 GCP is introduced. Flights without any GCPs lead to a significant height error in the order of up to 30 GSD.

Fluctuations in field vole abundance indirectly influence red grouse productivity via a shared predator guild

Changes in the abundance of one prey species may indirectly affect other prey species by triggering responses in generalist predators. Here we examine relationships between two prey species that do not compete directly, the field vole Microtus agrestis, a common rodent with fluctuating populations, and the red grouse Lagopus lagopus scotica, a gamebird inhabiting open moorland, during a 27-year study on a moor in south-west Scotland. First, we test whether vole abundance was related to grouse density and demographic rates. Second, we test whether vole abundance was related to abundance indices of four common predators of both voles and grouse (red fox Vulpes vulpes, weasel Mustela nivalis, hen harrier Circus cyaneus and common buzzard Buteo buteo). Third, we test whether these vole–grouse and vole–predator relationships differ in relation to grouse management, which includes the culling of foxes and weasels. We found no association between vole abundance and grouse densities, adult summer survival or nesting success. However, the ratio of young grouse per adult and the proportion of female grouse with broods in July were negatively associated with field vole abundance, suggesting increased predation of grouse chicks in years with high vole abundance. Fox indices showed a weak positive association with vole abundance when their numbers were not controlled, whilst weasel indices showed no relationship with voles. The numbers of breeding hen harriers and buzzards were also not associated with vole abundance, but the number of buzzard sightings was higher when voles were more plentiful. Our results are consistent with a negative interaction between field voles and red grouse chick survival in a pattern expected for apparent competition. Although the underlying mechanisms could not be disentangled, this interaction may be at least partly mediated by rodent-hunting raptors such as buzzards and, in periods without grouse management, foxes.

Impact of Sitka spruce (Picea sitchensis (Bong.) Carr.) afforestation on the carbon stocks of peaty gley soils – a chronosequence study in the north of England

This study aimed to quantify the medium-term impact of afforestation with Sitka spruce (Picea sitchensis (Bong.) Carr.) on C stocks of peaty gley soils through a 100 year chronosequence of 40 plots in Kielder Forest, northern England. Litter layer C stocks in the afforested plots were 4.11 t C ha⁻¹ (3.58–4.70, 95 per cent CI) compared with open moorland, which had no litter. In the organic F horizon, C stocks accumulated significantly through time at a rate of 1.3 per cent per year, with a significant difference in average C stocks by rotation (rotation 1: 49.7 t C ha⁻¹; rotation 2: 24.0 t C ha⁻¹) and a significant increase in horizon thickness through time (end of rotation 1: 11 cm; end of rotation 2: 6.5 cm) at a rate of 11 per cent per year (P < 0.05). There was no significant change in C stocks through time or across different rotations in the peat (H) horizon, with the exception of a noticeable C loss during the first 30 years of first rotation. H horizon C stock, its thickness and C concentration all increased significantly (P < 0.05) with altitude. Although soil C stocks in the mineral A horizon (0–20 cm depth) did not change significantly with any tested factors, soil C concentration significantly increased with afforested years. The average whole-profile (down to 70–100 cm depth) soil C stock rate of change with time since afforestation was not significant. These findings suggest that the high variability in C change in the peat H horizon was likely due to leaching, oxidation and decomposition processes linked with disturbance during afforestation and clearfelling. The loss of C in the peat layer during the first rotation was compensated by C accumulation in the upper organic F horizon. Over two rotations of conifer afforestation, the total C stock of the organo-mineral soils at Kielder was therefore unchanged.

What causes cooling water temperature gradients in a forested stream reach?

Abstract. Previous studies have suggested that shading by riparian vegetation may reduce maximum water temperatures and provide refugia for temperature-sensitive aquatic organisms. Longitudinal cooling gradients have been observed during the daytime for stream reaches shaded by coniferous trees downstream of clear cuts or deciduous woodland downstream of open moorland. However, little is known about the energy exchange processes that drive such gradients, especially in semi-natural woodland contexts without confounding cool groundwater inflows. To address this gap, this study quantified and modelled variability in stream temperature and heat fluxes along an upland reach of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland) where riparian land use transitions from open moorland to semi-natural, predominantly deciduous woodland. Observations were made along a 1050 m reach using a spatially distributed network of 10 water temperature data loggers, 3 automatic weather stations and 211 hemispherical photographs that were used to estimate incoming solar radiation. These data parameterised a high-resolution energy flux model incorporating flow routing, which predicted spatio-temporal variability in stream temperature. Variability in stream temperature was controlled largely by energy fluxes at the water-column–atmosphere interface. Net energy gains occurred along the reach, predominantly during daylight hours, and heat exchange across the bed–water-column interface accounted for &lt;1% of the net energy budget. For periods when daytime net radiation gains were high (under clear skies), differences between water temperature observations increased in the streamwise direction; a maximum instantaneous difference of 2.5 °C was observed between the upstream reach boundary and 1050 m downstream. Furthermore, daily maximum water temperature at 1050 m downstream was ≤1 °C cooler than at the upstream reach boundary and lagged by &gt;1 h. Temperature gradients were not generated by cooling of stream water but rather by a combination of reduced rates of heating in the woodland reach and advection of cooler (overnight and early morning) water from the upstream moorland catchment. Longitudinal thermal gradients were indistinct at night and on days when net radiation gains were low (under overcast skies), thus when changes in net energy gains or losses did not vary significantly in space and time, and heat advected into the reach was reasonably consistent. The findings of the study and the modelling approach employed are useful tools for assessing optimal planting strategies for mitigating against ecologically damaging stream temperature maxima.

Inter‐annual variability in the effects of riparian woodland on micro‐climate, energy exchanges and water temperature of an upland Scottish stream

AbstractThe influence of riparian woodland on stream temperature, micro‐climate and energy exchange was investigated over seven calendar years. Continuous data were collected from two reaches of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland) with contrasting land use characteristics: (1) semi‐natural riparian forest and (2) open moorland. In the moorland reach, wind speed and energy fluxes (especially net radiation, latent heat and sensible heat) varied considerably between years because of variable riparian micro‐climate coupled strongly to prevailing meteorological conditions. In the forested reach, riparian vegetation sheltered the stream from meteorological conditions that produced a moderated micro‐climate and thus energy exchange conditions, which were relatively stable between years. Net energy gains (losses) in spring and summer (autumn and winter) were typically greater in the moorland than the forest. However, when particularly high latent heat loss or low net radiation gain occurred in the moorland, net energy gain (loss) was less than that in the forest during the spring and summer (autumn and winter) months. Spring and summer water temperature was typically cooler in the forest and characterised by less inter‐annual variability due to reduced, more inter‐annually stable energy gain in the forested reach. The effect of riparian vegetation on autumn and winter water temperature dynamics was less clear because of the confounding effects of reach‐scale inflows of thermally stable groundwater in the moorland reach, which strongly influenced the local heat budget. These findings provide new insights as to the hydrometeorological conditions under which semi‐natural riparian forest may be effective in mitigating river thermal variability, notably peaks, under present and future climates. © 2014 The Authors. Hydrological Processes published by John Wiley &amp; Sons Ltd.

Effects on bird abundance and species richness of edge restructuring to include shrubs at the interface between conifer plantations and moorland

Capsule Bird species richness and (for most species) abundance were positively related to the extent of shrub cover at the interface between conifer plantations and moorland, but it appears that responses to shrub development vary between different bird guilds. Aims To assess the bird assemblages in both winter and breeding seasons at the interface between managed conifer plantations and open moorland, where that interface had been restructured to include a mosaic of shrubs and open ground. Methods Timed point counts were used to sample the birds at restructured plantation – moorland interface areas and also in neighbouring plantations (post- and pre-thicket age classes) and neighbouring moorland. Associations between species richness and abundances with measures of shrub cover and composition were assessed using GLMMs. Results A total of 60 bird species were recorded including 29 on lists of conservation concern, most of which were associated with shrub interface habitats. Species richness and, for most species, abundance were positively related to the extent of shrub cover. Positive relationships between shrub cover in interface areas and the abundance of some species in neighbouring plantations and open moorland suggested a resource subsidy to birds in neighbouring habitats. In contrast, some birds tended to be less abundant in plantations next to areas with more shrub cover. These species were more abundant in the shrub itself, suggesting redistribution by species with a preference for early successional shrub habitats. Conclusions The long-term management of shrub, especially with regard to successional development, is a challenging aspect of forest and landscape management that deserves further study.

The origin and temporal development of an ancient cultural landscape

AbstractAim To reconstruct the Late Glacial and Holocene vegetation history of western Tasmania and to test the long‐held notion of a replacement of forest by moorland during the mid to late Holocene in western Tasmania, Australia.Location Western Tasmania, Australia.Methods Fossil pollen data were screened with a modern pollen dataset using detrended correspondence analysis and charcoal data were analysed using significance tests.Results At the landscape scale, the distribution of vegetation types in western Tasmania has remained remarkably stable through the post‐glacial period. Open moorland has dominated the landscape since the Late Glacial, while rain forest expanded at that time in to areas which it occupies today. Vegetation development in the Holocene is markedly different and charcoal values are significantly higher when compared with those in previous interglacial periods.Main conclusions The dominant paradigm of a replacement of rain forest by moorland across western Tasmania during the mid to late Holocene is not supported by this regional analysis. The arrival of humans in Tasmania during the Last Glacial Stage provided an ignition source that was independent of climate, and burning by humans through the Late Glacial period deflected vegetation development and facilitated the establishment of open moorland in regions occupied by rain forest during previous interglacial periods. It is concluded that the present dominance of the landscape of western Tasmania by open moorland is the direct result of human activity during the Late Glacial and that this region represents an ancient cultural landscape.

A comparison of stream water temperature regimes from open and afforested moorland, Yorkshire Dales, northern England

AbstractDespite the known importance of water temperature for river ecosystems, the thermal regime of streams and rivers can be heavily modified by afforestation. Although the nature of the heat budget affecting streams in forested catchments shows high variability in space and time, most of the studies of stream temperature response to afforestation have lacked replication among streams. This study examined the impacts of coniferous forest plantations on stream water temperature at six sites (three forested and three open moorland) in the Yorkshire Dales, northern England. Our aim was to test the hypothesis that afforestation would alter the thermal regime of streams, leading to reduced year‐round thermal variability, and cooler summer/warmer winter water temperatures, relative to streams flowing across open moorland. Data collected from April 2007 to March 2009 showed similar thermal dynamics among all six streams over the study period, although variability in forested streams was markedly lower as expected. Mean and maximum daily water temperatures were significantly higher in open moorland streams for much of the year but while some forested streams were warmer than individual moorland streams during winter months (November to February), there was considerable overlap in water temperature between moorland and forest streams. Most stream temperature records showed evidence of low/no winter flow and freezing. These results contrast with many previous studies that have reported warmer temperatures in forested versus open moorland streams during winter, a finding that most likely reflects site‐specific hydrological, geomorphological and climatological influences on water temperature in addition to afforestation. This study demonstrates the need for replication of hydrological monitoring when examining the effects of basin‐scale management practices and provides further evidence for changes in stream thermal regime following afforestation, a practice that is likely to increase in future due to growing demands for increased forest cover in the UK uplands. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Making visions visible for long-term landscape management

Results generated by planning and futures studies are often too abstract to provide a clear vision of the future to non-specialists. In this study the role of 3D visualization and the challenges in developing and communicating visible visions for our future landscapes is explored. While traditional visualization techniques have been well-known for several hundreds of years digital 3D visualizations are still not yet taken advantage of in long-term planning or in futures studies in general to their full potential. As part of an iterative consultation and participation process a long-term vision for the landscape and land management of the Alport Valley in the Peak District National Park, UK is developed in order to improve the valley's special landscape character, to enhance the valley's visual and recreational attractiveness, to regenerate the woodlands in ways that maximize the long-term benefit of ecology, wildlife and landscape and to get a good balance between wooded areas and open moorland. An early integration of 3D visualization in the planning process offers a wide range of opportunities for exploring alternative futures but it also poses challenges to the expert planners such as being able to react timely, with a high degree of realism and interactively to incorporate new inputs from participating stakeholders. Furthermore, the planner is forced to translate a vision into concrete geographically referenced data. Only then the vision can be visualized. The full potential of 3D visualizations in the planning disciplines and in futures studies is still to be explored. The visualizations could be the basis to communicate the vision – the views of the future – and to share the vision with others in order to influence future change.

The role of deer as vehicles to move ticks, Ixodes ricinus, between contrasting habitats

In Europe the most important hosts maintaining Ixodes ricinus tick populations are deer. Therefore, excluding deer by fencing or culling are potential tick management tools. Here we test the hypothesis that deer act as vehicles for moving ticks between two distinct habitats: forest and open heather moorland. We utilised an ideal “natural experiment” whereby forests were either fenced or unfenced to prevent or allow deer to move between habitats. We aimed to test the hypothesis that deer cause a net movement of ticks from high tick density areas, i.e. forests, to low tick density areas, i.e. open moorland. We recorded I. ricinus and host abundance in 10 unfenced and seven fenced forests and their respective surrounding heather moorland. We found that fenced forests had fewer deer and fewer I. ricinus nymphs than unfenced forests. However, we found no evidence that fencing forests reduced I. ricinus abundance on adjacent heather moorland. Thus there was insufficient evidence for our hypothesis that deer cause a net movement of ticks from forest onto adjacent moorland. However, we found that deer abundance generally correlates with I. ricinus abundance. We conclude that fencing can be used as a tool to reduce ticks and disease risk in forests, but that fencing forests is unlikely to reduce ticks or disease risk on adjacent moorland. Instead, reducing deer numbers could be a potential tool to reduce tick abundance with implications for disease mitigation.

Influence of riparian cover on stream temperatures and the growth of the mayfly Baetis rhodani in an upland stream

This research aimed to assess whether stream temperature and the size of Baetis rhodani larvae (Insecta: Ephemeroptera) differed between sites with contrasting riparian vegetation cover. Stream temperatures and Baetis sizes were monitored at sites along a 5-km section of a small (30 km2) upland Scottish stream. Some sites had riparian tree cover dominated by mature broadleaved woodland, while others were located in areas of open Calluna moorland. The 13 month data period included two contrasting summers, one typical for the region and the other unusually warm. Daytime water temperatures were generally highest at the open moorland sites. The difference between moorland and broadleaved woodland sites was most apparent in the summer months, with the woodland shading apparently acting to reduce maximum temperatures and mediate temporal fluctuations. Size data suggest that Baetis has a bivoltine life-cycle in the stream. Significant differences in the mean size of Baetis were found between moorland and woodland sites, with differences occurring primarily during the summer months. Mean size of Baetis was significantly greater in the moorland during the time of summer adult emergence. During the months that followed (growth of the next generation), Baetis larvae in the woodland sites were significantly larger. Size distribution data for the population suggest earlier adult emergence in the moorland section and different egg-to-larvae hatch times. Overall, the results indicate that subtle differences in growth and life cycles, linked to differences in riparian cover and streamwater temperature, can occur over short distances in upland streams.

Altitudinal patterns of tick and host abundance: a potential role for climate change in regulating tick-borne diseases?

The impact of climate change on vector-borne infectious diseases is currently controversial. In Europe the primary arthropod vectors of zoonotic diseases are ticks, which transmit Borrelia burgdorferi sensu lato (the agent of Lyme disease), tick-borne encephalitis virus and louping ill virus between humans, livestock and wildlife. Ixodes ricinus ticks and reported tick-borne disease cases are currently increasing in the UK. Theories for this include climate change and increasing host abundance. This study aimed to test how I. ricinus tick abundance might be influenced by climate change in Scotland by using altitudinal gradients as a proxy, while also taking into account the effects of hosts, vegetation and weather effects. It was predicted that tick abundance would be higher at lower altitudes (i.e. warmer climates) and increase with host abundance. Surveys were conducted on nine hills in Scotland, all of open moorland habitat. Tick abundance was positively associated with deer abundance, but even after taking this into account, there was a strong negative association of ticks with altitude. This was probably a real climate effect, with temperature (and humidity, i.e. saturation deficit) most likely playing an important role. It could be inferred that ticks may become more abundant at higher altitudes in response to climate warming. This has potential implications for pathogen prevalence such as louping ill virus if tick numbers increase at elevations where competent transmission hosts (red grouse Lagopus lagopus scoticus and mountain hares Lepus timidus) occur in higher numbers.

Seasonality of epCO2 at different scales along an integrated river continuum within the Dee basin, NE Scotland

AbstractSpatial and temporal variations of free CO2 concentrations in surface waters are mainly controlled by dynamic processes encompassing terrestrial inputs and in‐stream biotic cycling. Free CO2 can be expressed as ‘excess partial pressure of CO2’ (epCO2), indicating supersaturation or under‐saturation with respect to atmospheric CO2. Seasonal patterns of epCO2 at sites draining nested upland catchments between 3·40 and 1837 km2 were assessed within the River Dee basin in NE Scotland. EpCO2 values ranged from 0·14 at the lowermost site on the mainstem in autumn to 12·7 on a major tributary during spring.A seasonality index was derived to describe contrasting winter/spring maxima and summer/autumn minima as annual mean epCO2 values could not clearly distinguish between different sites. Seasonal differences tended to increase downstream as progressive changes in physicochemical conditions enhanced the influence of autotrophic communities. However, perturbations to this continuum occurred as CO2 inputs from high DOC, heterotrophic tributaries and land‐use changes between open moorland and forest affected downstream continuity. Major tributaries showed reduced differences between seasons compared to the mainstem. Smaller headwaters indicated a lack of seasonality as high connectivity of responsive, peaty soils enabled continual inputs of terrestrially derived free CO2 to streams concomitant with limited autotrophic CO2 removal, maintaining epCO2 &gt; 1 throughout.Seasonality of epCO2 was mainly driven by the ability of in‐stream biota to consume CO2 during optimal conditions in summer/autumn. This was confirmed by multiple linear regression analysis, which indicated that, apart from catchment area, baseflow and biotic activity indicators were the best predictors of epCO2 seasonality characteristics at any particular stage of the river system. Copyright © 2009 John Wiley &amp; Sons, Ltd.

The influence of riparian woodland on stream temperatures: implications for the performance of juvenile salmonids

AbstractStream temperature was monitored at five mainstem locations and one tributary location on the Girnock Burn, a 31‐km2 tributary catchment of the Aberdeenshire Dee in north‐east Scotland. Stream temperature was recorded at 15‐min resolution between April 2003 and March 2006 to investigate the influence of semi‐natural riparian woodland on the spatial and temporal variability of stream temperature and the influence that this had on the performance of juvenile Atlantic salmon (Salmo salar). Two upstream sites were located in open moorland locations, while three downstream sites were located in areas of mixed deciduous/coniferous woodland areas at progressive distances of 0·75, 1·5 and 2·0 km from the upstream edge of continuous riparian tree cover. The effects of riparian woodland on stream temperature varied through the year, increasing during the spring to a maximum in summer, before decreasing once again in autumn. Maximum, mean and diel temperature amplitude were lower and minimum temperatures higher at woodland sites when compared to those located in open moorland. Although significant differences in fish performance were detected between sites, the influence of temperature variability was unclear due to confounding factors, some of which could not be measured during the study. It is recommended that future studies should combine advances in field‐based temperature monitoring with those in hydroclimatology to develop realistic process‐based models that can be used for stream temperature prediction. Further advances are needed in understanding the relationship between naturally variable thermal regime and fish performance in order that ecological predictions can be usefully made from field and modelled temperature data. © Crown Copyright 2008. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley &amp; Sons, Ltd.

Spectrophotometric properties of surface water dissolved organic matter in an afforested upland peat catchment

AbstractMany upland catchments in the UK have undergone afforestation; their characteristic waterlogged soils require extensive pre‐plantation ground drainage to allow tree establishment. In peatland areas this can result in very highly coloured runoff and enhanced dissolved organic matter (DOM) export in rivers of naturally high concentrations. In 1966, the Coalburn Experimental Catchment, northern England, was established to investigate the impact of afforestation on an upland peat catchment. Here we report the variations in DOM spectrophotometric properties of streamflow in the catchment at canopy closure, especially with respect to potential carbon sources within the artificial drainage ditches. Drainage ditches are characterized by water that has higher absorption coefficients and which is more highly coloured than in the catchment tributaries. Ditched, afforested areas produce more highly‐coloured runoff waters that are more fluorescent and absorbent normalized to carbon concentration compared to ditches in open moorland. Ditches that had been experimentally re‐excavated have organic matter of different spectrophotometric character, with higher dissolved organic carbon concentration and less aromatic or lower molecular weight material. It is hypothesized that this is due to the exposure of bare peat faces within and adjacent to the ditches that are more susceptible to drying compared to vegetated areas. The large extent of this drainage network acts as both a rapid transport network increasing hydrological connectivity and a pool for the storage of DOM, which is of different spectrophotometric character under low flow conditions, depending on management conditions. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Edge effects and arboreal Collembola in coniferous plantations

Summary We report on the distribution of arboreal Collembola in relation to canopy microclimatic conditions and distance from a forest edge. Collembola were collected by pyrethrum misting from the canopy of 12 m commercial plantations of Pinus sylvestris and Picea sitchensis at two sites in northern England, using transects running perpendicularly from a sharp edge (against open moorland). Temperature and humidity were co-recorded at 1.5 m elevation. Eleven species of Collembola were recorded, dominated by four known to be arboreal (Entomobrya nivalis, Lepidocyrtus lanuginosus, Vertagopus arboreus and Anurophorus laricis) but also including small numbers of supposedly edaphic forms, notably Protaphorura armata. All species were at higher density in the P. sitchensis plantations, but otherwise displayed no consistent community structure. Only four significant edge effects were detected in the Collembola data (out of 60 tests), none of which fitted an exponential model. By contrast the majority of the micro-meteorological data showed significant edge effects which were well modelled by an exponential function. It is concluded that the distribution of arboreal Collembola showed no edge effects, despite the latter being detectable in their meteorological environment.

Use of Multiplex Terminal Restriction Fragment Length Polymorphism for Rapid and Simultaneous Analysis of Different Components of the Soil Microbial Community ▿

A multiplex terminal restriction fragment length polymorphism (M-TRFLP) fingerprinting method was developed and validated for simultaneous analysis of the diversity and community structure of two or more microbial taxa (up to four taxa). The reproducibility and robustness of the method were examined using soil samples collected from different habitats. DNA was PCR amplified separately from soil samples using individual taxon-specific primers for bacteria, archaea, and fungi. The same samples were also subjected to a multiplex PCR with the primers for all three taxa. The terminal restriction fragment length polymorphism profiles generated for the two sets of PCR products were almost identical not only in terms of the presence of peaks but also in terms of the relative peak intensity. The M-TRFLP method was then used to investigate rhizosphere bacterial, fungal, and rhizobial/agrobacterial communities associated with the dwarf shrub Calluna vulgaris growing in either open moorland, a mature pine forest, or a transition zone between these two habitats containing naturally regenerating pine trees. Rhizosphere microbial communities associated with Vaccinium myrtillus collected from the native pine forest were also investigated. In this study, individual PCR products from the three taxa were also pooled before restriction digestion and fragment size analysis. The terminal restriction fragment length polymorphism profiles obtained with PCR products amplified individually and with multiplexed and pooled PCR products were found to be consistent with each other in terms of the number, position, and relative intensity of peaks. The results presented here confirm that M-TRFLP analysis is a highly reproducible and robust molecular tool for simultaneous investigation of multiple taxa, which allows more complete and higher resolution of microbial communities to be obtained more rapidly and economically.

The effect of experimental prescribed fire on the establishment of Scots pine Pinus sylvestris seedlings on heather Calluna vulgaris moorland

A key management objective for native Scots pine ( Pinus sylvestris) forests in Scotland is to extend the forest onto treeless moorland, below the natural tree line, dominated by the dwarf shrub, heather ( Calluna vulgaris). At Abernethy Forest, Scotland's largest native pinewood remnant, establishment of new tree seedlings on moorland has recently slowed despite the low grazing pressure. To investigate whether fire would be a useful management tool to improve the rate of regeneration of Scots pine, an experiment was carried out in 10 plots, on open moorland, on shallow peat soil, c 300 m from the forest edge. At each plot, 10 small exclosures were established, two for each of four burning treatments, and two controls. Within each exclosure, 100 Scots pine seeds were sown and the numbers of seedlings resulting were counted after 2, 11 and 30 months. Exclosures substantially reduced seed and seedling predation by mammals and invertebrates. The four burning treatments were single and double burns in the year of sowing, and single and double burns 1 year before sowing. Single burns removed largely heather, whilst second burns removed more of the moss. Burnt areas had 3.5 times (95% confidence limits 1.5–8.1) the number of seedlings established as controls, 2 months after sowing. There was no significant additional effect on seedling numbers of either double burning or year of burn. Slower-moving fires and, to some extent, shallower post-fire moss/litter depths, were associated with more seedlings establishing. Seedling numbers declined by 18% between months 2 and 11 and by 27% between months 11 and 30. The pattern of these declines was not significantly affected by treatment, post-fire moss/litter depth, or fire characteristics. The results have wide application at sites where Scots pine regeneration is a management aim, particularly on heather moorland, and where techniques which mimic natural processes are preferred. Managers at such sites should include prescribed burning, in conditions that produce slow-moving fires and shallow post-fire moss/litter depths, as a management option for improved Scots pine seedling establishment.