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Other Habitats (other + habitat)
Selected AbstractsStarling foraging success in relation to agricultural land-useECOGRAPHY, Issue 3 2002Ola Olsson Changes in agricultural land-use have been suggested to contribute to the decline of several bird species through negative effects on their food supply during breeding. One important change in land-use has been loss of pastures, especially permanent pastures. In this study we investigated how different forms of agricultural land-use affected foraging success of a declining bird species, the European starling Sturnus vulgaris. We let caged starlings forage in different forms of agricultural fields and determined time spent foraging and foraging success. The starlings' activity level (time spent actively foraging) as well as the number of prey caught per time unit was strongly related to the abundance of prey in soil samples. Also the body mass change during the experiment was positively related to activity level and prey capture rate. We found consistent differences in foraging variables between habitats. In spring sown grain starlings were least active and found fewer prey items at a lower rate than in any other habitat. The other three habitats differed less, but in general mowed hay fields appeared slightly more valuable than the cultivated and natural pastures. We did not find any differences between natural and cultivated pastures in foraging variables. Thus, starling foraging success is higher in grass-covered fields than in cultivated fields, but the management of the grass-covered fields mattered less. The results are consistent with starlings having higher population densities and breeding success in areas with higher availability of pasture. We suggest that the physical structure of the habitat (sward height) and moisture may be additional variables that need to be taken into account to explain starling breeding density and success in the agricultural landscape. [source] Trophic level modulates carabid beetle responses to habitat and landscape structure: a pan-European studyECOLOGICAL ENTOMOLOGY, Issue 2 2010ADAM J. VANBERGEN 1. Anthropogenic pressures have produced heterogeneous landscapes expected to influence diversity differently across trophic levels and spatial scales. 2. We tested how activity density and species richness of carabid trophic groups responded to local habitat and landscape structure (forest percentage cover and habitat richness) in 48 landscape parcels (1 km2) across eight European countries. 3. Local habitat affected activity density, but not species richness, of both trophic groups. Activity densities were greater in rotational cropping compared with other habitats; phytophage densities were also greater in grassland than forest habitats. 4. Controlling for country and habitat effects, we found general trophic group responses to landscape structure. Activity densities of phytophages were positively correlated, and zoophages uncorrelated, with increasing habitat richness. This differential functional group response to landscape structure was consistent across Europe, indicated by a lack of a country × habitat richness interaction. Species richness was unaffected by landscape structure. 5. Phytophage sensitivity to landscape structure may arise from relative dependency on seed from ruderal plants. This trophic adaptation, rare in Carabidae, leads to lower phytophage numbers, increasing vulnerability to demographic and stochastic processes that the greater abundance, species richness, and broader diet of the zoophage group may insure against. [source] Assemblages of soil macrofauna across a Scottish land-use intensification gradient: influences of habitat quality, heterogeneity and areaJOURNAL OF APPLIED ECOLOGY, Issue 6 2005PAUL EGGLETON Summary 1Land-use intensification strongly influences biodiversity by altering habitat heterogeneity, the distribution of habitat types and their extent. This study explores these effects within mixed semi-natural/agricultural mosaic habitats in Scotland, examining the effect of land-use intensification on the soil macrofauna at point (m2), landscape (km2) and regional (> 1 km2) scales. 2The soil macrofauna in six 1-km2 sampling areas (land-use units; LUU) were sampled using a combined hand-sorting and Winkler bag extraction technique. Within each LUU, 16 1-m2 samples were taken in each of 2 successive years. Each LUU had a mixture of land-use types, representing an agricultural intensification gradient. 3The following hypotheses were tested: (i) the study area sustains a number of distinct habitats as defined by soil macrofaunal composition; (ii) a greater number of restricted range species are found in semi-natural habitats; (iii) local (point) species density is related to habitat type; (iv) overall levels of species richness per habitat at regional scales are related to species-area effects; and (v) landscape-level species density is correlated with habitat heterogeneity. 4Initial analysis revealed five distinct habitat types: Caledonian forest (semi-natural pine forest), closed canopy woodland (pine plantation and broadleaved woodland), riparian habitats (wet woodland and grassland), pasture (improved grassland) and arable (crop fields). 5As hypothesized, the Caledonian habitat contained a greater number of restricted-range species than the other habitats. However, conifer plantations contained more restricted range species than expected, given their anthropogenic origin. Species density per m2 was most strongly affected by habitat type. At the regional level, the size of the species pool was correlated with the size of habitat areas. There were more species overall in LUU with greater habitat heterogeneity. 6Synthesis and applications. Caledonian pine forests have high species densities and contain species of conservation value. Mixed conifer plantations also appear to have a surprisingly high invertebrate conservation value. In contrast, intensively managed agricultural habitats have low species densities and conservation value. Generally, mixed land-use areas have higher species densities than single land-use areas. This emphasizes the need for careful management of forest systems within the matrix of agricultural habitats to maximize landscape diversity. [source] An investigation into the composition, complexity and functioning of snake communities in the mangroves of south-eastern NigeriaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2002Luca Luiselli Abstract The structure of the snake community was studied between 1996 and 2000 on a transect in the mangrove ecological zone of southern Nigeria, West Africa. In three major habitats, both taxonomical diversity and frequency of observations in relation to sampling effort were investigated. In general terms, the complexity of the snake community appeared less than in other habitats of the same geographic region (i.e. swamp forest and forest,plantation mosaics). In fact, only eighteen species were recorded, whereas 43 species are known to inhabit neighbouring habitats. A Principal Component Analysis allowed arrangement of the various species into two main groups in relation to the habitats of capture: (1) a group of species of rainforest biota (i.e. Toxicodryas blandingii, Thelotornis kirtlandii, Thrasops flavigularis, Rhamnophis aethiopissa, Gastropyxis smaragdina, Grayia smythii, Pseudohaje goldii, Python sebae), and (2) a group of species that, at least in Niger Delta, are typically linked to altered habitats, including derived savannas, plantations and suburbia (i.e. Psammophis cf. phillipsi, Philothamnus cf. nitidus, Hapsidophrys lineatus, Crotaphopeltis hotamboeia, Boaedon lineatus, Naja nigricollis, Python regius). The community structure in terms of food habits and body sizes appeared similar to those of other snake assemblages from different habitats of southern Nigeria. The conservation implications of our results are also discussed. Résumé On a étudié entre 1996 et 2000 la structure de la communauté des serpents dans un transect de la zone écologique de mangroves du sud du Nigeria, en Afrique de l'Ouest. On a étudié, dans trois habitats importants, la diversité taxonomique et la fréquence des observations par rapport à l'importance des échantillonnages. En termes généraux, la communauté des serpents y semblait moins complexe que dans d'autres habitats de la même région géographique (c.-à-d. la forêt marécageuse et une mosaïque de plantations forestières). En fait, on n'a rapporté que 18 espèces, alors qu'on sait que 43 espèces vivent dans les habitats voisins. Une Analyse du Composant Principal a permis de ranger les différentes espèces en deux groupes principaux, liés aux habitats où se sont faites les captures : (1) un groupe avec les espèces des biotes de forêt pluviale (Toxicodryas blandingii, Thelotornis kirtlandii, Thrasops flavigularis, Rhamnophis aethiopissa, Gastropyxis smaragdina, Grayia smythii, Pseudohaje goldii, Python sebae) et (2) un groupe d'espèces qui, au moins dans le delta du Niger, sont typiquement liées à des habitats dégradés, y compris des savanes dérivées, des plantations et des faubourgs urbains (Psammophis phillipsi, Philothamnus cf. nitidus, Hapsidophrys lineatus, Crotaphopeltis hotamboeia, Boaedon lineatus, Naja nigricollis, Python regius). La structure de la communauté, en ce qui concerne les habitudes alimentaires et la taille corporelle, était semblable à celle des autres groupes de serpents dans différents habitats du sud du Nigeria. On discute de l'implication de nos résultats pour la conservation. [source] Developmental changes in habitat associations of tropical treesJOURNAL OF ECOLOGY, Issue 3 2007LIZA S. COMITA Summary 1Recent studies have documented local-scale associations between tree species and topographic and edaphic habitat types in forests worldwide. To determine whether such associations form at early life stages, we compared species' positive associations with five habitat types (high plateau, low plateau, slope, streamside, and swamp) at two life stages for 80 tree and shrub species in a Panamanian lowland forest. 2Nineteen significant, positive habitat associations were detected at the small tree stage (seedlings and saplings , 20 cm tall and < 1 cm d.b.h.), and 18 at the large tree stage (individuals , 1 cm d.b.h.), according to results of torus-translation randomization tests. The majority of species did not show consistent associations at the two stages. Of the 30 species significantly associated with a habitat, only five were associated with the same habitat at both stages. Overall, more species were associated with the wetter slope habitat at the large tree stage compared with the small tree stage. 3For a subset of species, we examined the relationship between observed habitat associations and seed dispersal and seedling establishment patterns by using species-specific seed dispersal kernels to predict seed rain into each habitat. 4Two-thirds of species associated with a habitat at the large tree stage had higher predicted seed densities in the associated habitat relative to other habitat types, indicating that limited seed dispersal acts to reinforce habitat associations for most species. In contrast, only one-third of the species associated with a habitat at the large tree stage showed evidence of higher seedling establishment rates in the associated habitat compared with other habitats, and an equal number of species appeared to have lower rates of establishment in the habitat that large trees of the species were associated with. 5Overall, our results indicate that habitat associations of large trees typically do not form at early life stages. Rather, many species appear to exhibit different ecological habitat preferences across life stages. Future studies of species' habitat associations should therefore include multiple life stages in order to detect developmental shifts in ecological preferences. [source] Molecular phylogeny of Enchytraeidae (Oligochaeta) indicates separate invasions of the terrestrial environmentJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2010Bent Christensen Abstract Enchytraeidae is a family of soil inhabiting small- to medium-sized oligochaete worms using degradable plant material as a food source and primarily adapted to terrestrial or semi-terrestrial environments. The molecular phylogeny based upon both mitochondrial and nuclear genes indicates early segregations of the two genera Enchytraeus and Lumbricillus leaving the remaining genera included in this study as a later segregated major monophyletic branch. Extant members of the two former genera dominate in decaying seaweed in the littoral zone along the sea although members of in particular the genus Enchytraeus have also invaded other habitats. Historically the littoral zone of the sea is undoubtedly the first terrestrial or semi-terrestrial habitat where dead plant material accumulates to any greater extent and Enchytraeus and Lumbricillus may represent early successful attempts to exploit this resource. Inland soils probably had to await the emergence of land plants in order to provide a similar food resource and here the major branch of enchytraeid genera diversified into a high number of species in the numerous decomposer networks of this varied environment. A subdivision into the genera Enchytraeus and Lumbricillus on the one hand and a branch of mainly inland genera on the other is supported by differences in two somewhat neglected morphological features. Firstly, in Enchytraeus and Lumbricillus the testes are enclosed in a testis sac within which the male cells mature, by one possible exception a unique feature among Oligochaeta, The other enchytraeid genera studied and Oligochaeta in general lack this sac and the male cells mature directly in the cavity of the testicular segment. Secondly, species of Enchytraeus and Lumbricillus generally have a higher reproductive output than species of the inland terrestrial branch and this may represent an adaptation to the unpredictable littoral zone compared to the more stable nature of inland habitats. In the older literature the genus Mesenchytraeus is considered to have a basic position within the entire family but our molecular data do not support this expectation. In Enchytraeidae the nephridia are elaborate organs of a characteristic and constant shape covering species from different genera in a pattern following the molecular phylogeny. Other much used morphological features such as shape of setae, anteclitellar origin of the dorsal vessel and various modifications of the intestine have arisen more than once. Zusammenfassung Enchytraeidae sind eine Familie kleiner bis mittelgroßer edaphischer Oligochaeten, welche abbaubares Pflanzenmaterial als Nahrungsquelle nutzen und primär an terrestrische oder semiterrestrische Lebensräume angepaßt sind. Die hier vorgestellte, auf mitochondrialen und nukleären Genen beruhende molekulare Phylogenie indiziert eine frühe Abtrennung der beiden Gattungen Enchytraeus und Lumbricillus und beläßt die übrigen der in dieser Studie untersuchten Gattungen als eine später abgezweigte monophyletische Großgruppe. Rezente Glieder der beiden erwähnten Gattungen dominieren in verrottendem Strandanwurf des Meereslitorals, obwohl Arten insbesondere der Gattung Enchytraeus auch andere Lebensräume erobert haben. Historisch gesehen ist das Meereslitoral zweifelsohne das erste terrestrische oder semiterrestrische Habitat, in dem totes Pflanzenmaterial in größerem Ausmaß akkumulierte, und Enchytraeus und Lumbricillus könnten frühe erfolgreiche Versuche der Nutzung dieser Ressource darstellen. Festlandsböden dagegen bedurften wahrscheinlich der Entwicklung von Landpflanzen, um eine vergleichbare Nahrungsquelle zur Verfügung zu stellen, und hier diversifizierte sich der Hauptzweig der Enchytraeidengattungen in viele Arten in den diversen Zersetzernetzen dieses vielgestaltigen Lebensraums. Eine Unterteilung in die Gattungen Enchytraeus und Lumbricillus auf der einen Seite und einen Zweig mit vorwiegend terrestrischen Gattungen auf der anderen wird durch zwei bislang eher vernachlässigte morphologische Merkmale gestützt. Erstens, bei Enchytraeus und Lumbricillus wird der Hoden von einem Testis-Sack, in dem die männlichen Zellen reifen, umschlossen. Dies ist mit einer möglichen Ausnahme einzigartig bei Oligochaeten. Bei den übrigen untersuchten Enchytraeidengattungen und bei Oligochaeten generell fehlt dieser Sack, und die männlichen Zellen reifen unmittelbar in der Körperhöhle des Hodensegmentes. Zweitens, die Reproduktionsrate von Enchytraeus und Lumbricillus ist generell höher als die der Arten des Festlandszweigs. Dies könnte eine Anpassung an die im Vergleich zu Festlandsböden instabileren Bedingungen des Meereslitorals bedeuten. In der älteren Literatur wird der Gattung Mesenchytraeus eine basale Position innerhalb der gesamten Familie zugewiesen, aber unsere molekularen Daten stützen diese Annahme nicht. Die Nephridien der Enchytraeiden sind komplexe Organe mit einer charakteristischen und artübergreifend konstanten Form, deren gattungsmäßige Abwandlungen der molekularen Phylogenie entsprechen. Andere oft verwendete morphologische Merkmale wie Borstenform, anteclitellarer Ursprung des Dorsalgefäßes und verschiedene Darmmodifikationen sind mehr als einmal entstanden. [source] Effects of temporal and spatial variations in food supply on the space and habitat use of red squirrels (Sciurus vulgaris L.)JOURNAL OF ZOOLOGY, Issue 2 2000Peter W. W. Lurz Abstract In non-native conifer plantations characterized by strong spatial and temporal variations in the availability of tree seeds in Spadeadam Forest, northern England, the home range and habitat use of red squirrels Sciurus vulgaris was very flexible. Males tended to have much larger home ranges than females and core-areas of most breeding females seemed mutually exclusive. Adult female red squirrels were found to increase their home range and core-area size in forest patches where food was less abundant. Home-range size was significantly related to home-range quality and the extent of overlap by other females. In contrast with high-quality continuous conifer forests: (1) a considerable proportion of adult males and females at Spadeadam shifted home range, (2) both sexes had much larger home ranges than reported from other habitats in Britain or Belgium. Many ranges were multinuclear, particularly from January onwards, when supplies of seeds become depleted through consumption and seed shed. Squirrels tracked the availability of conifer seeds (lodgepole pine cones throughout the study, Norway spruce cones in spring 1992 and Sitka spruce cones in autumn 1993) and intensively used several non-adjacent activity centres in temporally food-rich patches. Consequently, habitat preference changed markedly with time. The squirrels seemed to maximize nitrogen intake and to avoid the smaller seeds when possible. This resulted in an overall preference for a mixed diet of lodgepole pine and spruce seeds and avoidance of Sitka spruce seeds when Norway spruce seeds were available. These results lend support to the hypothesis of Ostfeld (1985) that when food is sparse and patchily distributed, females should develop intrasexual territoriality, concentrating their activity in food-rich patches, while males should be non-territorial and adapt their space use to the distribution of females. [source] Community lifestyle of Candida in mixed biofilms: a mini reviewMYCOSES, Issue 6 2009Z. M. Thein Summary Candida is the most common human fungal pathogen that causes a variety of afflictions from superficial mucosal infections to deep mycoses. Biofilm formation is a major virulence factor of Candida, and more than 300 articles have been published on Candida biofilms over the past two decades. However, most of these data are on monospecies biofilms of Candida, and information on mixed-species Candida biofilms or bacteria,Candida combinations is still scarce. Yet, in nature, the yeast exist in a mixed milieu either in the oral cavity or in other habitats with a multitude of bacteria colonising mucosal surfaces within a shared community. This mini review describes the current knowledge on candidal,candidal or bacterial,candidal interactions in mixed-species biofilms. The underlying mechanisms of these interactions appear to depend on several factors relating to biofilm development, such as species and strains of organisms, nutritional factors, aerobiosis and related environmental factors. Although the fundamental nature of these interactions appears to be commensalism and antagonism, the emerging evidence based on novel molecular, proteomic and imaging tools indicates these biological mechanisms to be far more complex than hitherto recognised. Demystifying the mechanisms underlying the growth and development of mixed-species communities involving Candida will undoubtedly yield useful data for the effective management of microbial infections in general. [source] Reestablishment of the Southern California Rocky Intertidal Brown Alga, Silvetia compressa: An Experimental Investigation of Techniques and Abiotic and Biotic Factors That Affect Restoration SuccessRESTORATION ECOLOGY, Issue 2010Stephen G. Whitaker Previous research has indicated that many rocky intertidal macrophyte communities in southern California, and other locations around the world, have shifted from larger, highly productive, fleshy seaweeds toward a smaller, less productive, disturbance-tolerant flora. In widespread decline are ecologically important, canopy-forming, brown seaweeds, such as the southern California rockweed species Silvetia compressa. Restoration efforts are common for depleted biogenic species in other habitats, but restoration within rocky intertidal zones, particularly on wave-exposed coasts, has been largely unexplored. In two phases, we attempted to restore Silvetia populations on a southern California shore by transplanting live plants and experimentally investigating factors that affect their survival. In Phase I, we implemented a three-way factorial design where juvenile Silvetia thalli were transplanted at four sites with a combination of simulated canopy and herbivore exclusion treatments. Transplant survival was low, although enhanced by the presence of a canopy; site and herbivore presence did not affect survival. In Phase II, we used a two-way factorial design, transplanting two size classes of rockweeds (juveniles and reproductive adults) on horizontal and partially shaded, north-facing vertical surfaces at a target location where this rockweed has been missing since at least the 1970s. Transplant survival was moderate but lower than natural survival rates. Larger thalli exhibited significantly higher survival rates than smaller thalli in both the transplanted and naturally occurring populations, particularly on vertical surfaces. Higher mortality on horizontal surfaces may have been due to differences in desiccation stress and human trampling. Transplanting reproductive adults resulted in the subsequent recruitment of new individuals. [source] A Method for Evaluating Outcomes of Restoration When No Reference Sites ExistRESTORATION ECOLOGY, Issue 1 2009J. Stephen Brewer Abstract Ecological restoration typically seeks to shift species composition toward that of existing reference sites. Yet, comparing the assemblages in restored and reference habitats assumes that similarity to the reference habitat is the optimal outcome of restoration and does not provide a perspective on regionally rare off-site species. When no such reference assemblages of species exist, an accurate assessment of the habitat affinities of species is crucial. We present a method for using a species by habitat data matrix generated by biodiversity surveys to evaluate community responses to habitat restoration treatments. Habitats within the region are rated on their community similarity to a hypothetical restored habitat, other habitats of conservation concern, and disturbed habitats. Similarity scores are reinserted into the species by habitat matrix to produce indicator (I) scores for each species in relation to these habitats. We apply this procedure to an open woodland restoration project in north Mississippi (U.S.A.) by evaluating initial plant community responses to restoration. Results showed a substantial increase in open woodland indicators, a modest decrease in generalists historically restricted to floodplain forests, and no significant change in disturbance indicators as a group. These responses can be interpreted as a desirable outcome, regardless of whether species composition approaches that of reference sites. The broader value of this approach is that it provides a flexible and objective means of predicting and evaluating the outcome of restoration projects involving any group of species in any region, provided there is a biodiversity database that includes habitat and location information. [source] Key tree species for the golden-headed lion tamarin and implications for shade-cocoa management in southern Bahia, BrazilANIMAL CONSERVATION, Issue 1 2010L. C. Oliveira Abstract The golden-headed lion tamarin Leontopithecus chrysomelas occurs in the Atlantic forest of southern Bahia, Brazil, where shade-cocoa agroforestry (known as cabruca) predominates. The economic decline of the cocoa industry has caused many landowners to convert cabruca into cattle pasture or diversify their plantations with other crops. These and prior anthropogenic disturbances such as habitat fragmentation are threatening lion tamarin persistence. For some lion tamarin groups, cabruca comprises a large part of their home range. Considering these factors, the maintenance of the biological diversity in cabruca favorable to golden-headed lion tamarins is of considerable interest to their long-term survival. Here we identify plant species that provide food and sleeping sites for the lion tamarins and examine their occurrence in cabruca plantations, in order to investigate alternatives for conservation management practices that benefit both lion tamarins and cabruca. We determined the total number of trees and the frequency of individuals and species used for food and sleeping sites by lion tamarins in Una Biological Reserve, Bahia, from 1998 to 2006. We used this information to compare the richness and frequency of use across habitats (cabruca, mature and secondary) and to create a ranking index considering various components of a tree species' utility to the lion tamarins. Lion tamarins used 155 tree species, 93 for food and 93 for sleeping sites. Fifty-five species were ranked as ,Extremely Valuable,' eight as ,Valuable' and 92 as ,Of Interest.' Of 48 families, Myrtaceae and Sapotaceae were used the most. Cabruca contained fewer individual trees used by lion tamarins, but the highest frequency of use per tree compared with other habitats, indicating the large influence of single trees in these plantations. Using the key tree species identified in our study in the management of cabruca would be of considerable benefit to the long-term survival of lion tamarins [source] A rapid biodiversity assessment methodology tested on intertidal rocky shoresAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010Timothy D. O'hara Abstract 1.Conservation managers require biodiversity assessment tools to estimate the impact of human activities on biodiversity and to prioritize resources for habitat protection or restoration. Large-scale programs have been developed for freshwater ecosystems which grade sites by comparing measured versus expected species richness. These models have been applied successfully to habitats that suffer from systemic pressures, such as poor water quality. However, pressures in other habitats, such as rocky intertidal shores, are known to induce more subtle changes in community composition. 2.This paper tests a biodiversity assessment methodology that uses the ANOSIM R statistic to quantify the biological dissimilarity between a site being assessed and a series of reference sites selected on the basis of their similar environmental profile. Sites with high R values for assemblage composition have an anomalous assemblage for their environmental profile and are potentially disturbed. 3.This methodology successfully identified moderate to heavily perturbed sites in a pilot study on 65 rocky intertidal sites in south-eastern Australia. In general, measures based on percentage cover (flora and sessile invertebrates) were more sensitive than abundance (fauna). Copyright © 2010 John Wiley & Sons, Ltd. [source] Adaptive modifications of carapace outlines in the Cytheroidea (Ostracoda: Crustacea)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009GENGO TANAKA Shell outlines of 202 extant cytheroidean ostracods were analysed in dorsal, lateral, and posterior views by elliptic Fourier analysis. The results obtained confirm that the exterior morphology is related to ecological factors as well as phylogenetic constraints. Phytal species living on tall seagrass and benthic species burrowing in sediments are characterized and differentiated from the species crawling on sediments by the presence of slender shells with tapered venters. With reference to reconstruction of ancestral state of outline traits on the molecular phylogeny, the hypothetical ancestor of cytheroidean ostracods is presumed to have had an average-shaped shell. Morphological plasticity of the shell outline was observed in many families. The phytal species living on tall seagrass appear to have evolved convergently with species from other habitats, acquiring slim shell outlines during the Cenozoic period. The present analysis also reveals the phylogenetic constraints on the morphological evolution of the Trachyleberididae in their adaptation to a burrowing habit. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 810,821. [source] | |||||||||||||||||||