Habitat Distribution Of Species Research Articles

Comparing fishery-independent and fishery-dependent data for analysis of the distributions of Oregon shelf groundfishes

We investigate whether fishery-dependent time series can be used to fill in spatial and temporal data gaps where scientific, fishery-independent data are not available. Limitations in sampling coverage combined with a historical focus on continental slope-dwelling groundfish resulted in a gap in understanding Oregon’s nearshore groundfish fishery. Although fisheries-independent surveys have been conducted across most of the fishery’s depth range, the data are limited by years and seasons surveyed, as well as the absence of data for areas shallower than 55 m water depth. Fishery-dependent data are available for those shallow waters and for a broader temporal range. However, these data are self-reported and the coverage was determined by where fishers choose to fish. To investigate the potential for future combined uses for these data sources, we analyzed spatial and temporal changes in catch rates, as well as gaps in fishery (logbook) and scientific (NOAA survey) data, for six flatfishes. We found that more heavily targeted species that live in deeper water, like Dover sole and petrale sole, had more spatial scientific sampling coverage compared to less frequently targeted species that live in shallow water, such as starry flounder and sand sole. Overlap between datasets was variable in space and time but consistently higher near large ports. We identified the winter season, and the pre-2003 time-period as having the highest potential to benefit from complementary use of fishery-dependent data. Prior to 2003, the survey design was variable and there was greater spatial and temporal coverage of logbook data compared to post-2003. Integration of these data sets may be useful for future research given their differences in spatial and temporal range. This work provides a new perspective on the value of using fishery-dependent data to understand the spatial distribution of species in habitats that are under sampled in scientific surveys.

Diversity and Distribution of Cyatholaimidae (Chromadorida: Nematoda): A Taxonomic and Systematic Review of the World Records

Nematoda is a very species-rich phylum that has successfully adapted to almost all types of ecosystems. Despite their abundance and ecological importance, the taxonomic knowledge of nematodes is still limited and the identification of species is not trivial. In Cyatholaimidae, a relatively common and abundant family of free-living nematodes, the identification of organisms is challenging due to the overlap of some generic diagnoses and the absence of updated systematic reviews. Here we systematically reviewed the knowledge about the family diversity, providing a list of valid species, the diagnostic characters to genus level, and the geographical and habitat distribution of species. The review systematized a total of 619 records. The occurrences were classified into biogeographic ecoregions and habitats. Cyatholaimidae includes 211 valid species, classified in 20 genera. The genera can be differentiated based on six diagnostics characters, namely: pattern of cuticle ornamentation; number of longitudinal rows of pore-complex in cuticle; structures of the buccal cavity; presence/absence of pharyngeal bulb; pre-cloacal supplements aspect; and the shape of gubernaculum. Cyatholaimidae includes mainly marine species, mostly occurring in the Coastal Zone. Four and three species were registered in freshwater and terrestrial habitats, respectively, all classified in the genus Paracyatholaimus. About 38% of the valid species occur in more than one type of habitat, under very different environmental conditions, suggesting a broad niche. The occurrence of congeneric species in different habitats types indicates that, throughout the evolutionary history of the family, multiple ecological shift events have occurred. The family occurs worldwide in 74 ecoregions, and the majority of the records and species are in the North Sea and Western Mediterranean. Most species are endemic to one ecoregion, and examples of broadly distributed ones may be a result of misidentifications or cases of long-distance dispersal, especially for those associated with biological substrates.

Padrões de distribuição e abundância de gastrópodes límnicos no município de Acaraú, Ceará: avaliando aspectos da Teoria da Biogeografia de Ilhas

Na Teoria da Biogeografia de Ilhas, a relação espécies-área e o isolamento espacial podem influenciar na distribuição de espécies nos habitat. Nesse contexto, ecossistemas lênticos são utilizados para fornecer informações sobre mecanismos locais de diversidade de organismos, entre eles, moluscos. O presente estudo avaliou os aspectos ecológicos e biogeográficos de moluscos límnicos verificando a influência do tamanho e distância dos corpos hídricos na distribuição das espécies. A amostragem foi realizada em lagoas, classificada por perímetro com diferentes distâncias entre elas, em Acaraú, Ceará. Foram capturados 2.067 gastrópodes, distribuídos em seis famílias, seis gêneros e nove espécies. Foram coletados os planorbídeos Biomphalaria glabrata e Drepanotrema cimex, que ainda não haviam sido registrados para o Ceará. Não foram observadas diferenças significativas na riqueza, abundância e diversidade em relação ao tamanho das lagoas. Entretanto, há uma tendência de maiores índices em lagoas médias, o que pode ser resultante de distúrbios intermediários. Também não foram observadas similaridades na estrutura da comunidade entre corpos de água próximos, o que pode ser explicado pela facilidade de dispersão das espécies devido à enchente em períodos chuvosos. Os dados aqui apresentados podem ser importantes para compreensão dos mecanismos responsáveis pelos padrões de distribuição de moluscos límnicos no nordeste brasileiro.

Morphological Alterations in the External Gills of Some Tadpoles in Response to pH

Introduction Water pH affects the breeding, hatching, development, locomotion, mortality and habitat distributions of species in nature. The external gills of anuran tadpoles were studied by several authors in relation to abiotic factors. Exposure to low and high pH has been found to adversely affect the different tissues of various organisms. On that consideration, the present investigation was performed with tadpoles of the species Hyla annectans and Euphlyctis cyanophlyctis. Material and Methods The maximum and the minimum pH thresholds were determined prior to the detailed experiments on the effects of pH. The pH that demonstrated 50% mortality was taken as the minimum and maximum pH thresholds. The hatchlings of both the species were then subjected to different pH (based on the minimum and maximum pH thresholds). After 48 hours of exposure, the external gills of the hatchlings were anesthetized and observed under a scanning electron microscope. Results After 48 hours, clumping, overlapping and curling of the secondary filaments of the external gills and epithelial lesions in response to both acidic and alkaline pH were observed. The lengths of the secondary filaments were also affected by pH in both the species studied when compared with the control groups. Conclusion Scanning electron microscopic approaches are relevant in assessing the adverse effects of pH on the morphology of the external gills of H. annectans and E. cyanophlyctis tadpoles, which included problems with osmoregulation, acid-base balance and respiratory function.

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km) were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus), puma (Puma concolor), striped hog-nosed skunk (Conepatus semistriatus), and Andean bear (Tremarctos ornatus)]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Гриби класу Dothideomycetes лісових рослинних угруповань степової зони України

The species composition of class Dothideomycetes in the forest plants communities of the steppe zone of Ukraine has been studied. It includes 43 species from 26 genera, 20 families, 6 orders from 2 subclasses and group Incertae sedis. In the taxonomic structure of the investigated species composition it was established predominance of the subclass Pleosporomycetidae, of the order Pleosporales, the families Leptosphaeriaceae, Lophiostomataceae and Mycosphaerellaceae, and also genus Leptosphaeria. We have established the ecological structure of mycobiota and consortial connections with 33 species of plants from 25 genera 11 families. In the ecological structure it was marked the dominance of saprotrophs and xylotrophs. We analyzed the characteristics of habitat distribution of species in communities 3 types of vegetation. A comparison of the taxonomic spectra of Dothideomycetes of forest and steppe communities of the heath zone has been performed.

Use of herbarium data to evaluate weediness in five congeners.

It is often desirable to quantify a plant's relative weediness or synanthropy, that is, the degree to which a species associates with human-caused disturbance, in order to study and understand the biology, ecology and evolution of weeds and invasive plants. Herbarium specimens are among the most accessible and verifiable sources of data on distribution and habitat. However, the habitat distribution of species may not be reflected accurately by herbarium specimen data, due to well-known biases in plant collection. Here, we assess how well herbarium specimens reflect species' weediness, when compared with direct field surveys. We used five species of Melampodium (Asteraceae) and classified their degree of weediness with a modification of Nuorteva's synanthropy index, based on herbarium specimens. We then modelled the distribution of our focal species in Mexico using MaxEnt and identified a polygon of ∼3000 km(2) in the state of Nayarit, Mexico, where there was a high probability of finding all five species. Systematic field searches in the target area documented all visible populations of four species along major and minor roads. Then we, again, classified their degree of weediness with the synanthropy index, based now on field data, and compared. We found that herbarium data were an accurate predictor of a species' weediness relative to its congeners despite the well-documented skew of herbarium data towards natural areas, which our data reflected as well. So, herbarium data can be used to classify species' weediness relative to each other, but not in absolute terms, if the specimens were correctly identified and none of the species were subject to particular collection bias. This study is the first attempt to compare herbarium and field data on this subject and may be relevant for other types of investigations based on herbarium data. Our work also highlights the usefulness of distribution models based on herbarium specimens.

Germination performance of congeneric Styrax species from the Cerrado sensu lato areas and their distribution pattern in different physiognomies

When studying congeneric species, it is of reasonable importance to understand different ecophysiological performances which might determine the distribution of species in habitats with different natural resources. Styrax ferrugineus is exclusive and well adapted to the Brazilian Cerrado sensu stricto (s. str.); S. camporum is widely distributed in the Cerrado sensu lato (s. l.) areas, with young trees being observed at the edge of cerradão and other vegetation fragments; and S. pohlii occurs in permanently waterlogged soils of the Cerrado region, such as those of riparian forests. We tested the hypothesis that the higher the soil water content in the physiognomic gradient of the vegetation, the higher is the germination success of S. pohlii, but the lower is the germination success of S. ferrugineus. We also discuss whether gap conditions inside a cerradão fragment imply a high germination rates of seeds of S. camporum. Seeds from each of the three species were buried within nylon bags containing soil from the respective sites. Burial occurred in a Cerrado s. str., in understory and gap conditions of a cerradão, and in the understory of a riparian forest fragment, and lasted for 60, 120, 180 and 240 days, respectively, after the fruit dispersal time of each of the three species. After 60 days, a relationship was found showing that the percentage of germinated seeds diminished, and the percentage of damaged seeds increased as soil water content increased (Cerrado s. str.<cerradão gap<cerradão understory≪riparian forest). S. camporum still showed viable seeds 60 days after burial (DAB), and germinated seeds 120 DAB, indicating that it needed a longer time to germinate, which might be associated to its thicker seed coat, in relation to the other two species. The germination performance of each of the three species was the same in the gap and understory conditions of the cerradão. The higher concentration of adult S. camporum plants at the edge of vegetation fragments is not related to a particular high germination performance and seedling establishment.

Landscape patterns as indicators of ecological change at Fort Benning, Georgia, USA

This research examined landscape indicators that signal ecological change in both intensely used and lightly used lands at Fort Benning, Georgia. Changes in patterns of land cover through time affect the ecological system by altering the proportion and distribution of habitats for species that these cover types support. Landscape patterns, therefore, are important indicators of land-use impacts, past and present, upon the landscape. This analysis of landscape pattern began with a landscape characterization based on witness tree data from 1827 and the 1830s and remotely sensed data from 1974, 1983, 1991, and 1999. The data from the early 1800s, although coarse, were useful in characterizing the historical range of variability in ecological conditions for the area. The steps for the analysis involved the creation of a land-cover database and a time series of land-cover maps, computation of landscape metrics, and evaluation of changes in those metrics over time as evidenced in the land-cover maps. We focused on five cover types (bare/developed land, deciduous forest, mixed forest, pine forest, and non-forest vegetated land), for they reveal information important to resources management at Fort Benning. An examination of land-cover class and landscape metrics, computed from the maps, indicated that a suite of metrics adequately describes the changing landscape at Fort Benning, Georgia. The most appropriate metrics were percent cover, total edge (km), number of patches, descriptors of patch area, nearest neighbor distance, the mean perimeter-to-area ratio, shape range, and clumpiness. Identification of such ecological indicators is an important component of building an effective environmental monitoring system.

Diversity in crystal production by some bird's nest fungi (Nidulariaceae) in culture

Hyphae of many species of bird's nest fungi (Nidulariaceae) were examined for the presence of crystals. Scanning electron microscopy revealed crystals typical of calcium oxalate associated with hyphae. Crystal depositions included complete hyphal encrustation, organized druses, randomly arranged groups, single crystals, and relatively "clean" hyphae. The majority of crystals could be morphologically classified as styloid, raphide, or bipyramidal type. Energy-dispersive X-ray microanalyses confirmed that all crystal types were rich in calcium, and X-ray diffraction identified both the dihydrate (weddellite) and monohydrate (whewellite) forms of calcium oxalate. Morphological variation of crystals was species and medium specific, with generally more crystals being produced on relatively calcium-rich V8 juice agar than on PDA. No association was found between crystal types and geographic and habitat distribution of species. Keywords: wood rotting fungus, decomposition, calcium oxalate.