The population ecology of house mice (Mus domesticus) on the Isle of May, Scotland

The colonizing ability, catholic habitat utilization and wide distribution of house mice ( Mus domesticus , Rutty) are indicators of their ecological resilience. Numerous studies have been made of commensal, caged and free-living mouse populations though few have assessed the relative importance of physiological and genetical components of adaptability in a simple ecosystem. This paper reports such findings, derived from live-trapping which formed part of an inter-disciplinary study of adaptability in a feral population of house mice living on a small Scottish island (57 ha).
The population size ranged from450–3250 animals. A high proportion of mice showed homerange tenacity, though15–20% shifted their range during winter. This 'churning' of the population is consistent with the island population forming an effectively panmictic unit rather than fragmented demes. The breeding season, survival of individuals and change in population size related to patterns of gross climatic variation (temperature and rainfall) so that rates of reproduction and survival were lowest in cold, wet conditions. Thermoregulatory adjustment of the mice to lowered ambient temperatures and its contribution to overwinter survival are discussed. Genetical monomorphism of May Island mice is discussed in relation to their biological performance compared with other populations, especially that of the ecologically comparable Skokholm Island (Wales).     

The importance of the oil-shale Bings of West Lothian,Scotland, to local and national biodiversity

Summary

The oil-shale bings of West Lothian, Scotland, are a group of post-industrial waste sites, unique in Britain and Western Europe. The industrial exploitation of oil-bearing rocks has created a habitat with its own distinctive flora and fauna. The floral diversity of individual sites has been documented as species lists in several studies. A comprehensive list of more than 350 plant species, with supplementary information on animal species, was compiled from an extensive literature review of these studies. From these data it was possible to determine the extent of species variation within and between bings, identify locally and nationally rare species, and thus to determine the importance of the oil-shale bing habitat at a local and national scale. The results will go some way to allay concerns about the loss of local biodiversity, generally throughout the country side, due to changes in agricultural practices and increased urbanisation. Findings from the bings and evidence from other types of derelict land suggest that species are not lost, they have moved to new habitats.     

Trophic ecology of East African caecilians (Amphibia: Gymnophiona), and their impact on forest soil invertebrates

Diets of the syntopic caecilian amphibians Boulengerula boulengeri and Scolecomorphus vittatus were studied from gut content analyses of 108 specimens collected from Nilo Forest Reserve, East Usambara Mountains, Tanzania. Head length and width relative to body length is greater in male B. boulengeri than in females, but no such dimorphism is apparent in S. vittatus . No differences, other than females consuming disproportionately more ants and invertebrate eggs and fewer termites than males, occur in the diets of B. boulengeri . The gut contents of S. vittatus are dominated by large, surface-active earthworms, in contrast to those of B. boulengeri which contained smaller, endogeic earthworms and a much greater number and diversity of soil arthropods (particularly termites, ants and Diptera larvae). These dietary characteristics underline differences in microhabitat use between these caecilian species and thus corroborate a previously proposed hypothesis of niche separation. The ecological impact of caecilians and other limbless endogeic vertebrates is little studied and poorly known. Approximations based on current knowledge are not clear, but are interpreted as indicating that predation by caecilians is unlikely to be among the most important factors influencing population densities of soil-dwelling termites and perhaps also ants: two groups recognized as soil ecosystem engineers.     

Youngest early carboniferous (late Visean) shallow-water patch reefs in eastern Australia (Rockhampton Group, Queensland): Combining quantitative micro- and macro-scale data

Summary Although skeletal organisms have received most of the emphasis in studies on Phanerozoic roef history, the roles of non-skeletal (non-enzymatic) carbonates (e.g., synsedimentary cements, automicrite, microbialite, etc.) in reef framework construction are becoming increasingly better understood. One problem in understanding the role of non-enzymatic carbonates in reef construction has been the difficulty in recognizing them in reef facies. Whereas skeletal organisms commonly can be recognized and documented in the field, non-enzymatic carbonates may be recognizable only in thin section. This paper describes the application of a new sampling technique that allows the quantitative comparison of skeletal macrofauna and flora with associated non-enzymatic carbonates and other microfaunal/microfloral constituents. The technique involves the point counting of thin sections made from small diameter cores that are systematically recovered from grids and line transects that cover a reasonable area (m²) of reef facies. Small, shallow-water patch reefs are abundant in scattered oolitic intervals in the Lower Carboniferous strata of eastern Australia. The youngest known Carboniferous reefs in eastern Australia occur in uppermost Visean strata (limestone FC5) near the top of the Rockhampton Group, approximately 50 km west-northwest of Rockhampton, Queensland. The largest sampled reef was 15 m thick and 42 m in diameter, with synsedimentary relief above the sea floor of at least 2 m during the primary growth phase. The reef occurs within bioclasticoolitic grainstones representing a shallow shelf setting and consists of eight common framework microfacies: 1) coral boundstone; 2) bryozoan boundstone; 3) mixed crinoid-bryozoan boundstone; 4) tubular problematica boundstone; 5) sponge-automicrite boundstone; 6) encrusted thrombolite boundstone; 7) mixed automicrite boundstone; and 8) thrombolitic wackestone-packstone. Reef growth was initiated by automicrite-producing biofilms, sponges and a tubular problematic organism. Primary relief building was accomplished by automicrite-dominated frameworks and lithistid sponges, crinoids, and corals. Large cerioidAphrophyllum coral colonies had a heterogeneous distribution through the reef. The framework of the main relief-bearing portion of the reef consists on average of 44.4% automicrite and automicrite-bound detritus, excluding automicrite-bound sponge body fossils, and at most 19.6% skeletal organisms in growth position (minimum of 7.2%). If sponge body fossils are included as automicrite framework, because they are preserved only as a result of automicrite formation, the percentage of automicrite and bound sediment is 54.9%. A smaller sampled reef consisting of the same basic facies had 39.5% automicrite and automicrite-bound sediment in its fremework (50.2% including sponges) and, at most, 33.4% skeletal organisms in growth position (minimum of 22.7%). The greater volume of skeletal framework in the small reef reflects a greater proportion of large corals. Of framebuilding skeletal organisms, automicrite-preserved lithistid and other sponges and cerioid rugose corals provided the greatest volume. However, crinoid holdfasts were the most widespread skeletal framework components. The dominant framework facies are sponge-automicrite boundstone, encrusted thrombolite, boundstone, mixed automicrite boundstone, and coral boundstone. The reefs are similar in overall framework construction and ecological succession to slightly older Visean reefs in eastern Australia and to some of the late Visean reefs of northern England. Surprisingly, framework similarities also exist between the reefs and certain thrombolite-lithistid-coral reefs of the European Jurassic.     

The ecology of a scale insect,Aulacaspis tegalensis,on sugar cane in East Africa

• 1 The scale insect, Aulacaspis tegalensis, invaded a sugar estate near Moshi, Tanzania, in 1969.
• 2 The number of fields affected and scale abundance were estimated weekly by weighing eggs sifted from samples scraped from infested cane.
• 3 Abundance increased exponentially with the age of the cane, once mature cane began to develop at the age of six months, and it was also affected by the cane variety.
• 4 The principal source of temporal variation in abundance was weather, especially mean maximum temperature eight weeks before sampling, when the crawlers which gave rise to the females were settling.
• 5 The behaviour of crawlers is affected by temperature, humidity and sunshine.
• 6 Up to 25% of the crop was lost at the height of the infestation.
• 7 Wild natural enemies could not reduce scale numbers to an acceptable level.
• 8 Lindorus lophanthae (Coccinellidae) was introduced from Mauritius in 1971 and may have been responsible for the decline in scales which began after it had become abundant throughout the estate. Since 1972 loss of yield due to scale has been undetectable in the factory.
• 9 The results are discussed in relation to the situation in Mauritius, where L.lophanthae is ineffective and the implications of the studies for the reduction of losses by agronomic methods are detailed.

     

Three species of Isotoma (Collembola, Isotomidae) based on morphology, isozymes and ecology

Morphological markers and isozymes were used for identifying three presumed species of the Isotoma genus. Morphological traits separated three taxa of the genus. 10 isozymes determined by at least 11 loci were analysed from each taxon, and 2 loci were taxon-specific, supporting the hypothesis that the three taxa represented three species. The genetic variation found within the taxa measured as fraction of polymorphic loci at the 99% level was 0.82, 0.55 and 0.55 with the corresponding observed heterozygosity 0.15, 0.09 and 0.12. Two populations of the same taxon from Denmark and Norway, respectively, were very closely related. Additional ecological criteria, obtained from a literature survey, also revealed pronounced differences between the three taxa. Due to these facts three distinct species are proposed, namely I. anglicana Lubbock 1862, I. riparia Nicolet 1841 and I. viridis Bourlet 1839.     

A phyletic study on lacustrine haplochromine fishes (Perciformes, Cichlidae) of East Africa, based on scale and squamation characters

Phyletic relations within the haplochromine cichlids of East Africa were investigated using scale and squamation characters. Within the L. Victoria–Edward–Kivu species flock most of the genera proposed in Greenwood's revision could be confirmed by this approach. In addition the genera could be interrelated phylogenetically. They form two distinct superlineages comprising several genera each. The genus Astatotilapia as conceived by Greenwood is diphyletic. The fluviatile members of the genus form the sister taxon of the L. Victoria–Edward–Kivu flock, while the rest are a subgroup of that flock. The flock seems to be of monophyletic origin.     

Notes on the ecology of rolled-leaf hispines (Chrysomelidae,Cassidinae) at La Gamba (Costa Rica)

A total of 301 adult hispine beetles of the genera Cephaloleia and Chelobasis were found in rolled leaves of plants of 17 species of Zingiberales (families Costaceae, Heliconiaceae, Maranthaceae, Musaceae, and Zingiberaceae) during a field study at La Gamba, Golfito region, Costa Rica. Of these beetles, Cephaloleia belti was recorded from 12 potential host plant species, C. distincta from 7, C. dilaticollis from 5, C., Chelobasis bicolor, C. championi, and C. histrionica from 3, Chelobasis perplexa and C. instabilis from 2, whereas C. trivittata from only one. Of the plant species, Heliconia latispatha had 7 beetle species in its leaf rolls, Calathea lutea had 5, H. imbricata and H. rostrata had 4, H. stricta and Musa paradisiaca had 3, H. wagneriana had 2, while on H. vaginalis, H. danielsiana, H. densiflora, H. longiflora, Calathea crotalifera, C. platystachya, Goeppertia lasiophylla, Alpinia purpurata, Costus pulverulentus and Costus barbatus, H. densiflora, H. vaginalis, and H. danielsana only hispines of one species were found.Cephaloleia belti occurred together with beetles of six other hispine species, whereas Cephaloleia trivittata never shared a leaf roll with another hispine species. The remaining beetle species aggregated with one to four other hispines. Adults of C. belti and C. championi were frequently seen, occasionally also with C. dilaticollis, C. histrionica, and Chelobasis perplexa, to co-occur with the carabid Calophaena ligata in the same leaf roll without any sign of interspecific aggression.A comparison of host choices and the phylogeny of the hispines and of their host plants revealed no signs that beetles used species level phylogenetic relationships within the Zingiberales to select food plants. Obviously, within this plant order, rolled-leaf hispines choose their plant hosts in a nearly opportunistic manner. Seemingly, they use differences among plants at higher taxonomic levels but within the Zingiberales, the availability of young – rolled – leaves might be the actual decisive factor.     

Effects of small-scale habitat disturbance on the ecology of breeding birds in a Vermont (USA) hardwood forest

We studied territory placement and foraging behavior of breeding birds in relation to juxtaposition of forest vegetation and logged patches in southern Vermont, USA Different bird species used disturbed vegetation at differing spatial scales, depending on temtory size Four species Dendroica pensylvamca. Geothlypis trichas, Zonotrichia albicollis, Oporornis Philadelphia showed strong clumping of their small (< 0 5 ha) territories in logged patches and were absent or rare in undisturbed forest Eleven species (e g Seiurus aurocapillus, Vireo ohvaceus) tended to avoid logged areas, especially the centers of cut patches An additional 17 species fell between these two extremes, using a mixture of disturbed and undisturbed forest and showing no tendency to prefer one or the other These 17 species tended to have larger (1 to > 3 ha) territories than disturbance specialists We used ordination and quantitative matrix comparisons to describe and test relationships among 14 of the most common bird species according to their similarities in territory habitat structure, tree species composition, and foraging behavior These analyses did not reveal any strong associations between foraging behavior and use of cut versus uncut forest Habitat use by birds occupying this forest mosaic, with its strong local gradient of vegetation structure, was thus not associated with concurrent variation in foraging behavior The sizes of cut patches of forest (0 7-1 6 ha) in our study area may be close to the minimum required to attract distinct breeding assemblages of non-forest birds to otherwise undisturbed forest ecosystems Bird species that use patches of early-successional vegetation embedded m a forested landscape may adopt a fugitive strategy as they seek nesting habitats in the spring Careful use of forest management techniques may permit both forest-interior and early-successional bird species to coexist m the landscape     

Feeding ecology of spider monkeys (Ateles geoffroyi) at Tikal,Guatemala

Field study in tropical dry forest in Tikal National Park, Guatemala, revealed that spider monkeys (Ateles geoffroyi) devoted about 57% of feeding time to fruit (pulp), 20% to the unripe seeds of a single tree species, and the remainder largely to leaves and buds. Fruit, seeds, flowers and leaves ofBrosimum alicastrum (Moraceae) accounted for 56% of the diet, and there was very little predation on invertebrates. A severe drought occurred during 1975, the first year of the study, and a comparison between July of that year with July, 1978 shows that in the drought year there was heavier than normal reliance on fruit of the genusFicus (46% versus 14%) and depressed consumption ofBrosimum (11% vs. 54%). Dietary species diversity (Shannon's measureH) and evenness (Hill'sE) were markedly higher during the drought July than the normal July.     

Vassiljukia,a new colonial rugose coral from the Early Visean (Mississippian) of the Donets Basin (Ukraine) and NW Turkey

The cerioid colonial coral previously described as Lithostrotion columnariformis from the Early Visean of the Donets Basin (Ukraine) is here reattributed to the new genus Vassiljukia. This genus is introduced for colonial amygdalophylloid developing a stable cerioid habitus. It differs from amygdalophylloid proto-colonies by its ability to produce second generation offsets. This ability is proposed here as a definition to differentiate proto-colonial stages from genuine colonies within the rugose corals. Vassiljukia columnariformis is also known from equivalent strata of northwestern Turkey where it occurs with the oldest cerioid Lithostrotion and Ceriodotia. The origin and affinity of Vassiljukia columnariformis within the Amygdalophyllidae are also discussed.     

Feeding ecology of Saguinus bicolor bicolor (Callitrichidae: Primates) in a relict forest in Manaus, Brazilian Amazonia.

This study is part of a long-term ecological study of habitat and dietary requirements of the pied bare-face tamarin (Saguinus bicolor bicolor). One group was studied for 11 months in an area of secondary forest in a suburb of Manaus, Amazonas, Brazil. Three main vegetation types occurred inside the group's home range (12 ha): capoeira, older secondary forest and campinarana (white sand forest). The tamarins ate fruits (21 species), flowers (1 species), exudates (4 species), and arthropods (insects and spiders). They spent 14.3% of total activity time seeking and eating animal prey, and 9.9% feeding on plant material, mostly fruits. In general, fruits consumed were ripe, small and succulent. Trees used for feeding were low and had small crown diameters. Three plant species (Protium aracouchinni, Myrcia cf. fallax, and Couma utilis) were used intensively during the three seasons covered by the study period. The concentrated use of 3 fruit species, each for an extended period (one fruiting species per season), provided the tamarins with a regular food supply. Tamarins consumed exudates from holes in the bark of trees of the families Anacardiaceae and Vochysiaceae, as well as gum exuded from seed pods of Mimosaceae. Exudates were exploited during the dry season and at the beginning of the wet season. Group travel was primarily based on routes connecting the fruiting trees exploited, with foraging for animal prey occurring during travel. Tamarins searched for arthropods on trunks, branches and leaves and in trunk holes. The foraging and feeding tactics displayed by S. b. bicolor are closely linked to morphological characteristics (small size and weight, claw-like nails) that allowed access to energy-rich resources (arthropods and plant exudates) in different strata of the vegetation.     

The ecology and behaviour of a marine insect, Halobates fijiensis (Hemiptera: Gerridae)

Observations were made in Fiji on the adaptive strategies of a marine gerrid, Halobates fijiensis , a species of the only genus of insects to have successfully colonized the open sea. The immature stages spend most of their time in flotillas on sheltered water close to mangroves, whereas adults usually occur singly and on both sheltered and open water behind the protecting reef systems. Wind has a decisive influence on the distribution of H. fijiensis: in strong onshore winds, all stages, including adults, remain close to the shelter of mangroves, but in calm conditions, older immatures venture considerable distances from the mangroves. Halobates fijiensis feed on floating, dead insects. Adults of the chironomid fly Tanytarsus halophilae , whose larvae live on intertidal sea-grasses, accounted for over 60% of the prey items recorded. Halobates fijiensis feeds at around the time of high water, either as individuals or in small, well-dispersed groups. Eggs are laid on intertidal turtle grass (Syringodium) , green coralline algae (Halimeda) or occasionally coral rubble, at or shortly after the point of low water on days of extreme low spring tides. Halobates fijiensis is preyed upon by the robber-fly Clinopogon scalaris (Diptera: Asilidae). Field observations showed that there is a clear effect of group size on the distance at which an approaching predator model is detected.     

The relationships and ecology of Apodemus sylvaticus from the Small Isles of the Inner Hebrides, Scotland

Island races of the field mouse ( Apodemus sylvaticus ) have often been used to support particular theories of colonization or microevolution. Comparisons between Apodemus from a group of four islands in the Inner Hebrides (Rhum, Muck, Eigg and Canna) give support to the idea that the amimals were introduced onto these islands by man—mice first becoming established on Eigg and thence being transported to the other islands.     

The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi)

A herbivore can manipulate certain factors of its feeding behaviour in order to achieve the metabolic requirements for reproduction. These factors include the choice of habitat in which to feed, the selection criteria for choosing food items, and the time allocated to feeding or devoted to other energy-consuming activities. The manipulation of these behavioural factors by giraffe in the Serengeti National Park, Tanzania is analysed in relation to the seasonal changes in the quantity and quality of the food resource.
The pattern of habitat choice demonstrates seasonal movements by giraffe across the drainage catena in response to differences in the rates of browse production between woodland types.
Giraffe show a positive inter-specific selection for the minor food items with a low available biomass, and utilize the dominant species in approximate proportion to their availability. Plant part selection is shown for the flushing shoots with very high protein contents.
Selection criteria include a significant selection for phosphorus, and in the dry season a selection for high energy material by breeding females. With the high nutritional qualities of the diets, negative criteria such as secondary chemical compounds are important. Patterns of browse selection are correlated with inter-specific seasonal changes in plant phenology.
Giraffe devote more time to foraging as the biomass and quality of the food declines in the dry season. Energy is conserved by minimizing energy-consuming activities at the most demanding times of day.     

The ecology of a beech forest on Mt. Sanpoiwadake,Hakusan National Park,Japan I. Braun-Blanquet,TWINSPAN and DCA analysis

The Lindero membranaceae-Fagetum crenatae association on Mt. Sanpoiwadake, Hakusan National Park, Japan, has been classified using traditional Braun-Blanquet methods. The association was floristically sub-divided into six communities, all of which had been included as four subassociations by Hukusima (1982). The resulting table was compared with an analogous community table derived using computer-based TWINSPAN analysis. This dual approach was shown to provide a fully objective classification by method, the subjective element in the Braun-Blanquet method thus being substantiated TWINSPAN. Subsequent ordination of the data using DCA then provided a further degree of objective evaluation allowing any misclassified stand or species to be re-examined, and at the same time displaying the detailed inter-relationships between all species or stands.