Modelling of underwater light in freshwater lakes using survival and failure time analysis

1. This study presents a new approach to modelling subsurface irradiance using concepts from survival and failure time analysis. The model applies a modified Weibull distribution function to predict downwelling irradiance. Data sets from forty-seven Norwegian sites show extremely high coefficients of determination, up to 99.99%, when analysed by the Weibull model.
2. The uncritical use of a single k _d value to model underwater light conditions is likely to result in poor estimates of received irradiance. This error may amount to several hundred per cent. The practice of force-fitting linear least-squares regressions to log-transformed irradiance data inevitably leads to highly biased estimates of the true fraction of incident irradiance entering the water.
3. Wave effects causing fluctuations of subsurface irradiance are modelled with synthetic data and compared with field observations. Fluctuations of surface elevation by waves produce skewed frequency distributions of the underwater light field. The result of these effects, which are to reduce the accuracy of estimated model parameters, can be largely eliminated by carefully designing field procedures used for the acquisition of subsurface light data.     

Chemosymbiotic bivalves and stable carbon isotopes indicate hydrocarbon seepage at four unusual Cenozoic fossil localities

Four unusual Cenozoic fossil localities are identified here as ancient hydrocarbon seep sites using palaeontological, petrological, and stable carbon isotope data. Late Eocene carbonate-cemented sandstone bodies in the Wagonwheel Mountains in California were previously suspected to represent ancient hydrocarbon seep sites, but the relatively high δ¹³C_carbonate values (−12.2 to −5.0‰) suggest oil rather than methane seepage. The Oligocene fauna of the Elmira asphalt mine, Cuba, was previously interpreted as a mix of freshwater and marine taxa, but all species are here identified as belonging to marine groups, including the bivalve families Lucinidae and Vesicomyidae, whose extant members live largely in symbiosis with chemoautotrophic endosymbionts. A carbonate concretion from this site showed δ¹³C_carbonate values as low as −32.2‰, which most likely indicates methane seepage. A previously unpublished Oligocene fossil locality in Atlantico, northern Colombia, is dominated by large solemyid, mytilid, lucinid, and vesicomyid bivalves, which most likely lived with chemotrophic endosymbionts. Seepage of biogenic methane without a significant contribution of thermogenic methane is indicated by δ¹³C_carbonate values as low as −51.3‰. We confirm that the Pleurophopsis -dominated sites of the Heath Shale and Lomitos Chert in northern Peru are ancient seep sites, although the previous identification of Pleurophopsis peruviana as a vesicomyid is doubtful.     

Ethnozoology in Brazil: current status and perspectives

Ancient connections between animals and human are seen in cultures throughout the world in multiple forms of interaction with the local fauna that form the core of Ethnozoology. Historically, ethnozoological publications grew out of studies undertaken in academic areas such as zoology, human ecology, sociology and anthropology - reflecting the interdisciplinary character of this discipline. The rich fauna and cultural diversity found in Brazil, with many different species of animals being used for an extremely wide diversity of purposes by Amerindian societies (as well as the descendents of the original European colonists and African slaves), presents an excellent backdrop for examining the relationships that exist between humans and other animals. This work presents a historical view of ethnozoological research in Brazil and examines its evolution, tendencies, and future perspectives. In summary, literature researches indicated that ethnozoology experienced significant advances in recent years in Brazil, although from a qualitative point of view improvement is still needed in terms of methodological procedures, taxonomic precision, and the use of quantitative techniques. A wide range of methodologies and theories are available in different areas of learning that can be put to good use in ethnozoological approaches if the right questions are asked. The challenges to studying ethnozoology in Brazil are not insignificant, and the tendencies described in the present study may aid in defining research strategies that will maintain the quantitative growth observed in the recent years but likewise foster needed qualitative improvements.     

Matching thirty years of ecosystem monitoring with a high resolution microfossil record

1. Monitoring of the ecosystem of Lake Mývatn, Iceland, since 1975 has revealed extreme fluctuations in important food web components, such as chironomids and cladocerans, with amplitudes of several orders of magnitude and a period of 5–8 years. This study uses sediment cores from the lake to examine if the food web fluctuations appear in the microfossil record of the sediment. 2. Dating was achieved by means of a combination of ¹³⁷Cs and volcanic tephra and was fine‐tuned by wiggle‐matching of chironomid microfossil and monitoring data. 3. Cladocera exuviae and chironomid egg capsules in the uppermost 34 cm of sediment were compared with the monitoring record that consisted of 30 years of window trap catches of flying chironomids and a 16‐year record of chydorid Cladocera caught in activity traps. 4. The observed chironomid and cladoceran population fluctuations were reflected in the sediment record of chironomid eggs and of the exuviae of three of seven cladocerans: Alonella nana, Alona rectangula and Eurycercus lamellatus, which also had the most extreme fluctuations in the monitoring data (3–4 orders of magnitude). Chydorus sphaericus, and to some extent Alona quadrangularis and Acroperus harpae, showed regular fluctuations in the core that the monitoring did not reveal. Density of subfossil chironomid eggs correlated positively with that of larval head capsules but not with other microfossils. 5. This study shows a reasonably good correspondence between the fossil records of chironomids and cladocerans on the one hand and biomonitoring data on the other. The results pave the way for an extension of the food web history to much earlier time intervals of the ecosystem, allowing the study of long‐term variation in the food web dynamics, including the impact of climatic variation and other external forcing. The results also indicate the usefulness of chironomid egg capsules in palaeolimnological studies.     

Capture and commercialization of blue land crabs ("guaiamum") Cardisoma guanhumi (Lattreille, 1825) along the coast of Bahia State, Brazil: an ethnoecological approach

Background

Blue Land Crab (Cardisoma guanhumi) is one of the most important crustacean species captured and commercialized in Brazil. Although this species is not considered to be threatened with extinction, populations of C. guanhumi are known to be rapidly diminishing due to heavy harvesting pressures and degradation of their natural habitats, highlighting the necessity of developing and implanting management and protection strategies for their populations. There have been no ethnozoological publications that have focused specifically on C. guanhumi, in spite of importance of this type of information for developing efficient management plans of resource utilization. So, the present work describes the ethnoecological aspects of the capture and commercialization of C. guanhumi by a fishing community in northeastern Brazil.

Methods

Field work was carried out in the municipality of Mucuri, Bahia in Brazil, between the months of January and March/2011 through the use of open semi-structured interviews with all of the crustacean harvesters in city who acknowledged their work in capturing this species, totaling 12 interviewees. The informants were identified through the use of the "snowball" sampling technique. In addition to the interviews themselves, the "guided tour" technique and direct observations was employed.

Results

According all the interviewees, the C. guanhumi is popularly called "guaiamum" and is collected in "apicum" zones. They recognize sexual dimorphism in the species based on three morphological characteristics and the harvesters also pointed two stages in the reproductive cycle during the year and another phase mentioned by the interviewees was ecdysis. All of the interviewed affirmed that the size and the quantities C. guanhumi stocks in Mucuri have been diminishing. All of the interviewees agreed that the species and other mangrove resources constituted their principal source of income. The harvesters dedicated three to five days a week to collect Blue Land Crabs and the principal technique utilized for capturing is a trap called a "ratoeira" (rat-trap).

Conclusions

The results of the present work demonstrated that the community retains a vast and important volume of knowledge about C. guanhumi that could subsidize both scientific studies and the elaboration of viable management and conservation strategies for this species.     

A revision of West Palaearctic species of the Micropsectra atrofasciata species group (Diptera: Chironomidae)

Phylogenetic relations among selected Micropsectra (Diptera: Chironomidae) species are inferred using mitochondrial COII gene sequences and morphological characters. Both maximum parsimony and Bayesian analyses indicate a monophyletic atrofasciata species group. However, some species morphologically similar to M. atrofasciata (Kieffer) in the adult male, i.e. M. appendica sp. nov. and M. logani (Johannsen), are placed outside the atrofasciata group in the gene trees. The phylogenetic hypotheses based on parsimony analyses of the combined molecular and morphological data sets weakly support a monophyletic atrofasciata group including M. appendica sp. nov. and M. logani if third positions in the COII gene sequences are excluded. In the taxonomic part of this study, adult males, pupae and larvae of Micropsectra aristata Pinder, M. atrofasciata, M. bavarica sp. nov., M. klinki sp. nov., M. logani, M. pallidula (Meigen) and M. schrankelae sp. nov. , and adult males and pupae of M. appendica sp. nov. and M. sofiae sp. nov. as well as adult males of M. andalusiaca Marcuzzi, M. calcifontis sp. nov., M. freyi Storå, M. longicrista sp. nov., M. robusta sp. nov. , and M. zernyi Marcuzzi are described and diagnosed. Micropsectra bidentata (Goetghebuer), M. jokaquarta Sasa & Ogata, M. miki Marcuzzi, M. pallida Goetghebuer, M. subnitens Goetghebuer, M. suecica (Kieffer) and M. shouharasima Sasa are new junior synonyms of M. atrofasciata; Micropsectra groenlandica Andersen and M. utonaitertia Sasa are new junior synonyms of M. logani; Micropsectra candida Chaudhuri & Datta, M. franzi Goetghebuer and M. viridiscutellata Goetghebuer are new junior synonyms of M. pallidula. Comments on the ecology, distribution and systematics of each species are provided. Keys to all known life stages are presented, as well as an annotated list of species morphologically similar to species in the atrofasciata group and nomina dubia in the atrofasciata group. Chironomus mimulus Holmgren is transferred to the genus Micropsectra. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 146 , 165–225.     

Phylogenetic relationships of nonbiting midges in the subfamily Tanypodinae (Diptera: Chironomidae) inferred from morphology

The nonbiting midge subfamily Tanypodinae represents one of the most diverse lineages of Chironomidae. Despite the wide distribution and high diversity of tanypodine chironomids, the evolutionary history of the subfamily remains poorly understood. Here, we present the first phylogenetic analysis of the subfamily Tanypodinae based on morphological data. Cladistic analyses were conducted using 86 morphological characters from 115 species belonging to 54 tanypodine genera, including the eight currently recognised tribes: Anatopyniini, Clinotanypodini, Coelopyniini, Macropelopiini, Natarsiini, Pentaneurini, Procladiini and Tanypodini. We use characters from fourth‐instar larvae, pupae and adults of both sexes. We examine the effects of implied weighting by reanalysing the data with varying values of concavity constant (k). Our analysis supports the monophyly of Tanypodinae with Podonominae as its sister group. All previously proposed tribes are recovered as monophyletic assemblages under a wide range of weighting factors. Under these conditions, the genus Fittkauimyia is the sister group of the remaining Macropelopiini and is erected as a new monobasic tribe, Fittkauimyiini trib.n . The tribe Pentaneurini is recovered as monophyletic with some internal relationships resolved. The genus Paramerina, recovered as sister of Reomyia + Zavrelimyia, is formally synonymised with Zavrelimyia syn.n. , based on morphological similarity in all three life stages and treated as a subgenus of the latter. Finally, the recently suggested synonymies of Gressittius and Guassutanypus with Alotanypus and the establishment of the subgenera Conchapelopia (Helopelopia), Macropelopia (Bethbilbeckia), Monopelopia (Cantopelopia), Thienemannimyia (Hayesomyia) and Zavrelimyia (Reomyia and Schineriella) are investigated. Our results support all proposed changes, except for the subgenus‐level status of Helopelopia and Cantopelopia. We suggest re‐establishment of Helopelopia as a genus, but refrain from promoting genus‐level status of Cantopelopia at present because the apparent sister‐relationship between Monopelopia + Nilotanypus likely is due to wing vein reduction caused by miniaturisation. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:DF012C17‐AFB3‐4904‐83DC‐30DD94D0B376 .     

CONSUMER INVOLVEMENT AND EVALUATION OF GREEN PEAS1

This paper reports the effect of consumer involvement on overall acceptance of frozen peas used in green salad and the effect of consumer involvement on the consumer's ability to perceive variations in a set of physical/chemical characteristics such as AIS (Alcohol Insoluble Solids) and color. The results reveal that consumers with high involvement evaluate 16 experimentally varied pea samples more in accordance with quality indicators used in the industry than consumers with low involvement. In our study 61% of the consumers were highly involved. For low involved consumers there was no relation between average acceptance and the quality indicators used by producer/retailer and retailer/consumer. High involved consumers could identify more of the physical/chemical variation in the pea samples than the low involved consumers. The results stress the importance of a preliminary segmentation of consumers. The low involved consumers do not seem to have any specific preferences for any of the samples included in the study although samples are varied considerably with respect to size, color and amount of sucrose. It may be considered as indifference. An obvious conclusion to draw from the results of this study is to concentrate on the highly involved consumers in further product development.     

Do increases in agricultural yield spare land for nature?

Feeding a rapidly expanding human population will require a large increase in the supply of agricultural products during the coming decades. This may lead to the transformation of many landscapes from natural vegetation cover to agricultural land use, unless increases in crop yields reduce the need for new farmland. Here, we assess the evidence that past increases in agricultural yield have spared land for wild nature. We investigated the relationship between the change in the combined energy yield of the 23 most energetically important food crops over the period 1979–1999 and the change in per capita cropland area for 124 countries over the same period. Per capita area of the 23 staple crops tended to decrease in developing countries where large yield increases occurred. However, this was counteracted by a tendency for the area used to grow crops other than staples to increase in the countries where staple crop yields increased. There remained a weak tendency in developing countries for the per capita area of all cropland to decline as staple crop yield increased, a pattern that was most evident in developing countries with the highest per capita food supplies. In developed countries, there was no evidence that higher staple crop yields were associated with decreases in per capita cropland area. This may be because high agricultural subsidies in developed countries override any land-sparing pattern that might otherwise occur. Declines in the area of natural forest were smaller in countries where the yield of staple crops increased most, when the negative effects of human population increases on forest area were controlled for. Our results show that land-sparing is a weak process that occurs under a limited set of circumstances, but that it can have positive outcomes for the conservation of wild nature.