Freshwater and wetland plant communities of Loch Lomond

Information on the aquatic and wetland vegetation of Loch Lomond, Scotland, is summarised for the period 1957–90. Aquatic macrophyte growth is estimated to occupy about 1% of the loch's total surface area, being limited to the 0–10 m euphotic zone, and probably excluded from much of this area by wave disturbance and unsuitable substrates. Aquatic vegetation is however abundant in sheltered bays and less-exposed shorelines, particularly in the South Basin of the loch. Although Littorella uniflora (L.) Aschers is the commonest, ubiquitous, submerged plant of the loch, three separate euhydrophyte communities have been identified within the loch. One of these is characterised by abundant stands of Elodea canadensis Michx., which appears to have invaded Loch Lomond some time between 1967–88, and has rapidly spread throughout the loch.     

The physico-Chemical limnology of Loch Lomond

Loch Lomond, the largest freshwater lake in Britain, is physically divided into a number of distinct basins by geological structures. The northern part of the loch is long, narrow and deep whilst the southern area is broad and shallow with many islands scattered throughout it.The water chemistry of the loch is dictated by the geology of catchment and the quality of the rivers flowing into it. The two major rivers, the Falloch and the Endrick Water, are both of good quality with low nutrient content. Consequently, the loch is regarded as oligotrophic, though the southern area verges towards being mesotrophic.     

Has habitat heterogeneity promoted phenotypic and ecological sub‐structuring among a Coregonus lavaretus population in a large Scottish lake?

Differences in stable‐isotope values, morphology and ecology in whitefish Coregonus lavaretus were investigated between the three basins of Loch Lomond. The results are discussed with reference to a genetic investigation to elucidate any substructuring or spawning site fidelity. Foraging fidelity between basins of Loch Lomond was indicated by δ¹³C and δ¹⁵N values of C. lavaretus muscle tissue. There was, however, no evidence of the existence of sympatric morphs in the C. lavaretus population. A previous report of two C. lavaretus‘species’ in Loch Lomond probably reflects natural variation between individuals within a single mixed population.     

Zooplankton in Loch Lomond: perspectives,predation and powan

Published and unpublished accounts of the zooplankton community of Loch Lomond are reviewed. Loch Lomond's zooplankton community is unique amongst those of Scotland's other large lochs. Holopedium gibberum appeared in Loch Lomond in the years between the studies of Slack & Hamilton in the 1950s and zooplankton surveys in the late 1970s.The annual cycles of Eudiaptomus gracilis, Cyclops strenuus abyssorum and Mesocyclops leuckarti are described for the mid basin of Loch Lomond. E. gracilis overwinter mainly as adult with variable egg production during their lifespan of 5–8 months. The cyclopoid copepods have variable life history characteristics. C. str. abyssorum produce a single generation per year, overwinter by means of resting eggs and a small population of planktonic adults, while M. leuckarti is present in the plankton throughout the year, but in low numbers during winter.Zooplankton populations in Loch Lomond are predated by the diverse fish community which includes a facultative planktivore in the powan, Coregonus lavaretus. Powan feed heavily on zooplankton from late spring until late autumn. Powan display selectivity in the prey species taken, in the size distribution and morph types taken within prey species. Zooplankton species, morphs and forms in Loch Lomond tend to reflect this predation.Zoology Department, University of St. AndrewsZoology Department, University of St. Andrews     

A comparative assessment of temporal variation in diet of powan, Coregonus lavaretus (L.), from Loch Lomond and Loch Eck, Scotland, U.K.

Stomach contents of powan caught throughout the year from Loch Lomond and Loch Eck were examined. Adult powan in Loch Lomond fed mainly on planktonic Cladocera, switching to benthic food during December-April. Bosmina coregoni was the principal planktonic food with Daphnia hyalina an important late summer and autumn prey. Loch Eck powan fed throughout the year on chironomid larvae and Pisidium spp. from the benthos and ingested large amounts of non-food material. Mean dry weights of food in stomachs were correlated with water temperature in Loch Lomond but not in Loch Eck and were higher in powan from Loch Eck over most of the year.     

Morphological abnormalities in a population of Lampetra planeri,with a short review of petromyzontid teratologies

Reported here are several deviations (n = 15; 1·96%) from typical morphology in a large sample (n = 767) of European brook lamprey Lampetra planeri from a single population in the Loch Lomond catchment; this includes one specimen bearing a true anal fin. A brief review of petromyzontid teratology is provided.     

Geology of the Loch Lomond catchment

Loch Lomond is unusual in its geographical position and relationship to underlying geological structures. To the north-west of the Highland Boundary Fault the bedrock is composed mainly of the Dalradian Supergroup, a sequence of regionally metamorphosed Late Precambrian marine sediments. Immediately to the south-east of the Highland Boundary Fault the Highland Bonder Complex includes fragments and slices of ophiolitic origin and sediments with a range of Ordovician ages. The Dalradians may have originated in a remote location on the northern margin of Gondwanaland. To the south-east of the Highland Border the bedrock lies within the Midland Valley of Scotland and consists entirely of Upper Palaeozoic rocks of Devonian and Carboniferous age. The nature of the bedrock has an influence on the environment of Loch Lomond with respect to slope stabilities and water quality.     

A seasonal and ecological study of the phytoplankton of Loch Lomond

The seasonal succession of phytoplankton in Loch Lomond has been studied both quantitatively and from observations on net plankton. From a qualitative investigation of net phytoplankton Loch Lomond may be described as diatom-desmid in nature although from the quantitative studies the general domination of the population by diatoms becomes clear. During the vernal phytoplankton increase diatoms contributed more than 90% of the population throughout the loch. The bulk of the phytoplankton production occurred in the southern region, where the standing crop was considerably greater throughout the year than in other regions of the loch.Patterns of seasonal succession are described for all species which make an important contribution to the productivity of the loch and the observed successions related to measured physical and chemical changes in the water. Explanations are put forward to account for the absence of a second (autumnal) pulse ofMelosira in Loch Lomond. The appearance ofAnabaena circinalis is a possible indication of the changing trophic status of the southern region of the loch.     

The age and growth of perch (Perca fluviatilis L.) in two Scottish lochs

This study is concerned with the age and growth of perch ( Perca fluviatilis L. ) in two contrasting Scottish lochs-the Dubh Lochan and Loch Lomond. Age and back-calculated growth were determined from annual rings in the opercular bones, and during the 2-year project 470 perch from the Dubh Lochan and 796 from Loch Lomond were examined. Growth in length in the two lochs, though similar for the first 2 years, differed thereafter, the average length at 8 years in the Dubh Lochan being less than 15 cm, that in Loch Lomond more than 23 cm at the same age. In neither locality did the growth of perch follow the Von Bertalanffy growth formula. Reasons for differential growth rates are discussed and comparisons made with the growth of perch in other waters in Europe and North America.     

Modern pollen from the catchment and surficial sediments of a Scottish sea loch (fjord)

Modern pollen was extracted both from moss polster samples collected from a range of sites across the land surface of the Loch Sunart catchment, north‐west Scotland and from a number of marine sediment‐water interface sites in the sea loch. Comparisons between the pollen results and the major vegetation types growing in the catchment area revealed that in general the moss polsters contained a localised picture of the vegetation whilst the sea loch sediments varied much less from sample to sample and better represented a regional picture of the vegetation. It was anticipated that the pollen in the sea loch samples would be in a much poorer state of preservation because of the many pathways through which it travels in order to become incorporated into the sediments of the loch. However, this proved not to be the case and the study demonstrates that marine sediments of the kind found in Loch Sunart have the potential to provide a new source of Holocene vegetation data which is as good as the freshwater lake sediments that have been preferentially sampled in the past.     

The ecology of lampreys (Petromyzonidae) in the Loch Lomond area

All three lamprey species occurring in western Europe are found in the Loch Lomond area: Sea Lamprey Petromyzon marinus L., River Lamprey Lampetra fluviatilis (L.) and Brook Lamprey Lampetra planeri (Bloch). There are major differences in ecology among the three species and in each some features seem to be unique to the Lomond populations. Available data on the ecology of the three species in the area are presented and existing threats reviewed. Future research and conservation requirements are outlined.     

Continuous variation in the pattern of marine v. freshwater foraging in brown trout Salmo trutta L. from Loch Lomond, Scotland

Carbon stable-isotope analysis showed that individual brown trout Salmo trutta in Loch Lomond adopted strategies intermediate to that of freshwater residency or anadromy, suggesting either repeated movement between freshwater and marine environments, or estuarine residency. Carbon stable-isotope (δ¹³C) values from Loch Lomond brown trout muscle tissue ranged from those indicative of assimilation of purely freshwater-derived carbon to those reflecting significant utilization of marine-derived carbon. A single isotope, two-source mixing model indicated that, on average, marine C made a 33% contribution to the muscle tissue C of Loch Lomond brown trout. Nitrogen stable isotope, δ¹⁵N, but not δ¹³C was correlated with fork length suggesting that larger fish were feeding at a higher trophic level but that marine feeding was not indicated by larger body size. These results are discussed with reference to migration patterns in other species.     

The fish community of Loch Lomond,Scotland: its history and rapidly changing status

The fish community of Loch Lomond is of national importance. Its diversity of species and rare populations of powan (Coregonus lavaretus) and freshwater feeding river lampreys (Lampetra fluviatilis) warrant high conservation status. It is also of value for its sport fisheries for sea-trout (Salmo trutta), salmon (Salmo salar) and pike (Esox lucius). Historical records demonstrate that the species composition of the fish community has remained stable over a very long period until recently when a series of introductions of fish species new to the catchment has resulted in successful colonisation by a number of species. These have resulted in fundamental changes in the ecosystem. Here using historical records the long-term stability of the fish community is examined, recent rapid changes in the fish community are documented and some of the resultant effects of changes in the fish community are demonstrated.     

A pollen diagram from Pitbladdo,Fife

Summary

Pollen analytical data are presented from a site near Cupar, Fife. The stratigraphy and pollen spectra are used to infer the changing patterns of vegetation in the area during the Lateglacial and Postglacial periods. In the Lateglacial Interstadial the local development of Betula-Juniperus scrub was followed by a period of open habitat during the colder Loch Lomond Stadial. The early Postglacial forest was dominated by Corylus and Betula, although Ulmus was also a major woodland component before the arrival of Alnus. Following some initial deforestation due to anthropogenic activity, subsequent woodland clearance was almost total and open habitat communities dominated.     

Impacts of land-use on West African savanna vegetation: a comparison between protected and communal area in Burkina Faso

Biodiversity matters in many aspects for human well-being by providing timber and non-timber products. The most important ecosystems providing these products in West Africa are savannas. In the context of land-use changes, there is an urgent need to understand the impact of land-use on savanna vegetation and biodiversity. This study assesses the impact of land-use on savannas by comparing protected and communal areas. Vegetation relevés were performed in the W National Park and its surrounding communal area in Burkina Faso. Vegetation types were established using ordination and clustering methods. We analyzed to find which environmental factors determine the occurrence of the vegetation types and whether land-use has a specific effect on diversity of vegetation types occurring in both areas. Furthermore, we tested the effect of land-use on vegetation structure and the occurrence of life forms and highly valued tree species. Our results reveal five vegetation types occurring in both areas. Elevation and soil characteristics played the most important role for the occurrence of the vegetation types. Land-use had an effect on vegetation structure, diversity, and the occurrence of life form and highly valued species. Our findings suggest that traditional human land-use does not automatically lead to loss of species and degradation of savanna habitats and that combination of communal and protected areas may be of great importance for the conservation of broad spectrum of biodiversity. Our study demonstrates the complexity of land-use impact on biodiversity patterns and provides insights on what kind of management activities may be most appropriate in both areas.     

Development of a spatially explicit approach for mapping ecosystem services in the Brazilian Savanna – MapES

The objective of the presented study is the development of a spatially explicit approach for mapping ecosystem services (MapES) by using specific knowledge about the Cerrado biome (Brazilian Savanna). This biome covers an area of about 2 million km², i.e. nearly 24% of the total area of Brazil, and has come under substantial pressure during the last 50 years caused by strong land-use/land-cover change, mostly due to agricultural expansion and urbanization. Because of its fast transformation rate, there is an enormous demand for knowledge, and its application, about the effects of land-use/land-cover on the capacity of providing or maintaining ecosystem services. The MapES approach was developed using a vast existing knowledge base. After analyzing and structuring this knowledge the relationships between land-use/land-cover and the potential to provide or maintain eight ecosystem services (Erosion Control, Runoff Control, Water Supply, Water Quality Maintenance, Soil Quality Maintenance, Biodiversity Maintenance, Food Production and Energy Production) were parametrized. In addition, the approach was developed as spatially explicit by including landscape properties (soil, slope and distance to river network) in the cell based system. A reference map of potential natural vegetation and a land use map for 2013 for a meso-scale experimental catchment (32.7 km²) were produced. The catchment was used as an example to apply the approach, i.e. assessing and visualizing changes from before human interference to the current land use situation. Finally, a procedure for assessing the potential impacts of land-use/land-cover on ecosystem services considering the methodological limitations of the respective monitoring. The presented approach is easy to understand, to modify and to adapt to other situations and might be therefore used in other context of decision support. It might also help to fill the gap between land use planning and numeric modeling using very complex tools.     

A multivariate morphometric and meristic description of a population of freshwater-feeding river lampreys, Lampetra fluviatilis (L.), from Loch Lomond, Scotland

Adults of a freshwater-feeding population of Lampetra fluviatilis (L.) in Loch Lomond, Scotland, were trapped on their upstream (spawning) migration in the main inflow to the loch, the Endrick Water. These animals could be distinguished from the more typical anadromous upstream migrant L. fluviatilis , from the Endrick Water and the nearby catchment of the River Forth, principally by their smaller total length, greater disc, snout and eye size and much darker pigmentation. These, and other morphometric and meristic characteristics have been compared for populations of L. fluviatilis and Lampetra planeri (Bloch) from the Lomond and Forth catchments using univariate and multivariate statistics. The Endrick Water 'dwarf' L. fluviatilis was found to differ significantly from the other Lampetra studied, in a number of body proportions in addition to those traits mentioned above, and also in mean numbers of trunk myomeres and teeth. These differences are likely to be due to a combination of the effects of genetic isolation, and the short (freshwater) feeding phase of the 'dwarf' L. fluviatilis , which may, therefore, represent the intermediate stage between parasitic and non-parasitic forms in the L. fluviatilis/L. planeri species pair.     

The winter diet and parasitic fauna of a population of Rednecked Wallabies Macropus rufogriseus recently introduced to Scotland

Although the Red-necked Wallaby is native to south-east Australia and Tasmania, at least four colonies have become established in the UK and two of these still survive. Here we provide the first account of a colony that became established following the deliberate release of four individuals to an island in Loch Lomond, Scotland in 1975. Data presented here show that this population is well established, having grown to at least 26 individuals by 1992. Wallaby diet in winter (a critical period for survival in the other remaining UK population) is composed of Blaeberry Vaccinium myrtillus and Heather Calluna vulgaris, each making up 35% of the plant fragments by occurrence in faecal pellets, with grasses making up a further 13%. Two species of parasitic coccidian protozoa and four species of strongyle nematode were found in faecal samples from this colony but the infection rate was low compared with what limited published data exist for this species. The possible reasons for the success of this most northerly of the UK wallaby populations are its isolation, the maritime climate and vegetation structure of the inhabited area.     

Changes in Rotifer Species Composition and Abundance along a Trophic Gradient in Loch Lomond,Scotland, UK

Loch Lomond is the second largest body of freshwater in Great Britain. It is a long, narrow lake (36.4 km long, 8.8 km wide). The northern basin is fjord-like and surrounded by a mountainous, base-poor, rocky catchment. In contrast, the southern basin is much broader and shallower with a mainly lowland, calcareous, agricultural catchment. This causes a trophic gradient along the length of the loch that runs from the oligotrophic northern basin to the more mesotrophic southern basin. Rotifer samples were collected at monthly intervals between May and October 2002 at three locations along the length of the loch. More than 12 species were found, the commonest of which were Keratella cochlearis (Gosse) and Trichocerca stylata (Gosse). Although the species composition of the rotifer community varied very little among the sites, rotifer abundance increased markedly from north to south, apparently reflecting the trophic gradient along the length of the loch. The results suggest that rotifer abundance may be a more sensitive indicator of trophic state, and changes in trophic state, than species composition.     

Long-term changes in the woodlands of Clairinsh

Summary

The mixed oak woodland on the island of Clairinsh has been left unmanaged as part of the Loch Lomond National Nature Reserve. Until 1913 the woodlands had been treated as coppice-with-standards. Between 1961 and 1986 changes in the structure and composition of the stand were recorded by means of two transects, within which individual trees and shrubs were charted and measured. Most of the stand remained closed, increasing in basal area, but decreasing in density. However, a limited number of canopy gaps formed, part-icularly as a result of the 1968 hurricane. Of the individuals present in 1961, 30% died by 1986, mortality being particularly high in smaller individuals and in birch. Recruitment was mainly confined to rowan, holly and hazel in the closed woodland, and to birch and rowan in the gaps. The changes are discussed in relation to natural processes and the history of management.