The classification and management of limestone pavements - an endangered habitat

This thesis describes an in-depth study of limestone pavements across North West England and North Wales. The aim was to combine elements of geodiversity and biodiversity in order to create a holistic limestone pavement classification to inform future management. A field-based research protocol was used to assess a stratified random sample (46 pavements), accounting for approximately 10% of the limestone pavements in the geographical area. Detailed analyses of key elements are presented, along with important issues that continue to pose threats to this Annex One Priority Habitat. This research resulted in a comprehensive classification, using TWINSPAN analysis and Nonmetric Multidimensional Scaling, identifying six distinct holistic functional groups. The prime factors driving limestone pavement morphology, and hence the classification, were established to be lithology, proximity to structural fault, altitude and human intervention, particularly in terms of grazing intensity. Three upland, open limestone pavement classes were formed. Of these, the richest in terms of geodiversity and biodiversity was the group with the thickest bedding planes and hence the deepest grikes, typically greater than 1m. The class that was most species-poor was "at the highest altitude (above 450m), formed on the thin limestones of the Yoredales. These were characterised by shallow, wide grikes. The third upland limestone pavement group had mid-range grikes, generally 0.5-1m in depth, and small clints. Two wooded classes were identified. One was a lowland 'classic' wooded limestone pavement group with deep, narrow grikes and shallow soils. Indicator species included Juniperus communis and Taxus baccata. The second wooded group was situated proximal to a major structural fault. In this group the pavement dip ranged between 10°-40° with well-runnelled clints that were heavily moss-covered. The sixth group was low altitude, proximal to the coast, characterised by low moss growth, un-vegetated clints and the presence of Ulex europaeus. Conservation management was identified as key to the quality of the limestone pavement habitat and this thesis identifies best management practises and links these to the holistic limestone pavement classification. Finally, as a sample case study, this thesis presents mollusc species and diversity from eleven of the Yorkshire limestone pavements. Analysis establishes significant links between geodiversity and mollusc populations, with key drivers for mollusc communities echoing those of plant species on limestone pavement.Funded by the Yorkshire Dales National Park and the University of Chester

Limestone Pavements in Great Britain and the Role of Soil Cover in Their Evolution

Članek obravnava povezavo med korozivno močjo prsti in skalnimi oblikami v apnencu. V ta namen so vzorcem iz različnih škrapljiπč, drugih oblik kraškega površja in vrtač v Severni Angliji, določili pH in delež karbonatov. Rezultati meritev so potrdili, da so oblike pod kislo prstjo globlje in da prisotnost apnenca močno zvišuje pH prsti.The goal of the research was to verify the connection between the solutional power of soil and the shape of rocky features in limestone. Soil samples from runnels, grikes, foot of pavements, top of limestone, grass patches and dolines were collected on limestone pavement areas of North England and examined for the pH and carbonate content. The results of the measurements proved that the soils with lower pH are related to deeper solution features and that proximity to limestone causes a higher soil-pH

Using presence-absence data to establish reserve selection procedures that are robust to temporal species turnover

Previous studies suggest that a network of nature reserves with maximum efficiency (obtained by selecting the minimum area such that each species is represented once) is likely to be insufficient to maintain species in the network over time. Here, we test the performance of three selection strategies which require presence-absence data, two of them previously proposed (multiple representations and selecting an increasing percentage of each species' range) and a novel one based on selecting the site where each species has exhibited a higher permanence rate in the past. Multiple representations appear to be a safer strategy than selecting a percentage of range because the former gives priority to rarer species while the latter favours the most widespread. The most effective strategy was the one based on the permanence rate, indicating that the robustness of reserve networks can be improved by adopting reserve selection procedures that integrate information about the relative value of sites. This strategy was also very efficient, suggesting that the investment made in the monitoring schemes may be compensated for by a lower cost in reserve acquisition

Geomorphology of the Durmitor Mountains and surrounding plateau Jezerska Površ (Montenegro)

The geomorphological map of the northeastern Durmitor Mountains and the plateau Jezerska Povrs. (1: 10,000, 47 km(2), Montenegro, Dinaric Alps) was prepared from an intensive fieldwork campaign and remote sensing analysis, and was compiled within a GIS. The basic components of the legend are (i) processes/genesis, (ii) materials, (iii) morphometry/morphography, (iv) hydrography, (v) vegetation and (vi) anthropogenic features. The geomorphological setting of the area consists of Mesozoic limestones which are physically deformed by Quaternary glacial and periglacial activity and chemically affected during interglacials. Glacial deposits on the plateau of three middle-to-late Pleistocene glacial phases are intersected by a well-developed network of palaeo meltwater channels. In the mountains, Holocene glacier retreat left behind a series of well-preserved recessional moraines. The map serves as a valuable tool for Quaternary research in the Durmitor Mountains, and also in other mountains of the Western Balkans

Robustness of reserve selection procedures under temporal species turnover

Complementarity-based algorithms for the selection of reserve networks emphasize the need to represent biodiversity features efficiently, but this may not be sufficient to maintain those features in the long term. Here, we use data from the Common Birds Census in Britain as an exemplar data set to determine guidelines for the selection of reserve networks which are more robust to temporal turnover in features. The extinction patterns found over the 1981-1991 interval suggest that two such guidelines are to represent species in the best sites where they occur (higher local abundance) and to give priority to the rarer species. We tested five reserve selection strategies, one which finds the minimum representation set and others which incorporate the first or both guidelines proposed. Strategies were tested in terms of their efficiency (inversely related to the total area selected) and effectiveness (inversely related to the percentage of species lost) using data on eight pairs of ten-year intervals. The minimum set strategy was always the most efficient, but suffered higher species loss than the others, suggesting that there is a trade-off between efficiency and effectiveness. A desirable compromise can be achieved by embedding the concerns about the long-term maintenance of the biodiversity features of interest in the complementarity-based algorithms

Performance Evaluations of Crushed Sandstone Aggregates in Bituminous Bases

The principal objective of the research effort was to develop historical performance data for bituminous sandstone pavements and bituminous limestone pavements relative to visual distress, pavement rutting characteristics, and structural condition using deflection measurements. Data relative to Road Rater deflections, pavement rutting, condition ratings based on subjective visual surveys and objective data such as skid resistance and rideability, were collected and analyzed during the course of the study and reported herein for the routes investigated. It was concluded, based upon information gained during the evaluation period and presented in this report, that pavements constructed with bituminous sandstone bases do not develop excessive rut depths, are more resistant to shoving and pushing, but appear to exhibit cracking at an earlier age than pavements constructed with bituminous limestone bases. The use of bituminous sandstone mixtures addresses problems such as haul costs, rutting, skid resistance, etc. Field engineers indicated that although bituminous sandstone surface mixtures have a slight tendency to ravel, they are very resistant to rutting and applications of bituminous sandstone base and surface mixtures have been very successful in their estimation

Valuing the landscape benefits of rural policies actions in Veneto (Italy)

<p class="p1">This study addresses, with reference to the landscape, a precise request of the EU to quantify the benefits of public expenditure in agriculture. It analyses the implications on rural landscape of some measures of the Common Agricultural Policy at a regional level, taking the Rural Development Programme (RDP) 2007-2013 of the Veneto Region, in north-eastern Italy, as case study. A choice experiment (CE) is applied to value four measures of the RDP that directly affect the landscape characteristics.<br />The CE results point out that the landscape benefits of the measures in the Veneto RDP are higher than the subsidies paid to farmers for the provision of services that improve landscape quality. The CE results suggest the opportunity to rethink the distribution of the subsidies.</p

Human impact on limestone pavement

&#091;cat&#093; Els paviments calcaris de les Illes Britàniques forneixen interessants exemples de l’activitat humana com a agent de canvi geomorfològic. Aquest article contempla la historia de la influencia humana en els paviments calcaris, especialment a l’Anglaterra nord-occidental, examina danys recents, i discuteix les accions realitzades per protegir aquestes formes paisatgístiques tan belles corn fascinants. Han estat diverses les activitats que han afectat els paviments, i la importància de les activitats individuals ha canviat amb el temps. Darrerament la pressió s'ha incrementat i els organismes conservacionistes s'han interessat pel problema per tal de protegir els paviments de nous estralls. Durant els darrers 30 anys, molts pocs paviments calcaris de les Illes Britàniques han deixat d'esser afectats per agressions o alteracions, i alguns han patit molt seriosament.&#091;eng&#093; The limestone pavements of the British Isles provide an interesting example of human activity as an agent of geomorphological change. This paper looks at the history of human influences on limestone pavements, especially in northwestern England, examines recent damage, and discusses the actions being taken to protect these fascinating and beautiful landforms. The activities which have affected the pavements have been varied, and the importance of any individual activity has changed over time. In recent decades the pressures have increased and conservation bodies have become concerned with the problem in order to protect pavement sites from further damage. Very few pavement sites in the British Isles have been unaffected by damage or alteration in the past 30 years, and come have suffered very severely