bluuebunny/crossref_metadata_2025 huggingface dataset:
Crab carapace hydrodynamics
Authors: Blake R. W.
Published: August 2010

The hydrodynamic properties of the carapace of the swimming crab, (Callinectes sapidus, Portunidae) and two dissimilar benthic species, Cancer productus and Lopholithodes mandtii, are investigated employing flow visualization and low‐speed wind tunnel techniques. Drag and lift forces for different orientations are determined for angles of attack ranging from 0–20. For Callinectes and Cancer productus drag is least at all angles of attack for sideways placement of the carapace, which corresponds to the position during locomotion in both species. Values of the drag Coefficient (based on plan form area) for Reynolds numbers greater than 104 for C. sapidus and C. productus are of the order of 0.2 0.35. Maximum values of the lift coefficient are of the order of 1.2 and 0.6 ‐0.7 for C. supidus and C.productus, respectively, giving maximum lift to drag ratios of about 4.0 for C. sapidus and 2.0 for C. productus. In contrast, L. mandtii is characterized by relatively high drag coefficients, low lift coefficients (about 1.0 and 0.2, respectively) and a lift to drag ratio that is an order of magnitude less than that of C. productus.

The adaptive significance of the different lift to drag ratios of the animals is discussed in the context of simple hydromechanical models of carapace design in relation to flow velocity. It is argued that the carapace of Callinectes is adapted for minimum resistance and to generate sufficient lift to counter excess weight over buoyancy (specific gravity, S.G. = 1.14) at low forward speeds. Assuming that all of the lift required is produced passively by the carapace, minimum swimming speeds of the order of 0.15 ms‐1 are calculated.

The model applied to the benthic species focuses on two critical velocities, the slipping speed (speed at which lateral displacement first occurs) and the lift‐off speed (speed at which the animal is lifted off the bottom). The ratio of lift‐off speed to slipping speed for C. productus is approximately 1.9 and similar to that for plaice. Values for L. mandtii are about 3.3. It is suggested that the carapace of C. productus is adapted to maximize slipping speed and that displacement in L. mandtii is resisted actively by holding on to the substratum. The influence of flow on crabs in general is briefly discussed in relation to morphological design and habitat.
The effect of differences in herbage height on the grazing behaviour of lactating Bennett's wallabies (Macropus rufogriseus rufogriseus)
Authors: Clarke J. , Loudon A. S. I.
Published: August 2010

The grazing behaviour of lactating Bennett's wallabies was studied on a number of different pasture types. Increases in mean sward height resulted in a greatly reduced bite rate and an increase in the search time per bite. All wallabies showed a diurnal rhythm in grazing activity irrespective of habitat type, with least grazing activity at midday and most at night. Animals maintained on very short grass swards compensated for the reduced herbage mass by extending their grazing activity into the midday period. Lactating animals grazed for longer, had higher biting rates and a greater number of estimated bites per day than non‐lactating wallabies (17,700 vs. 7600 bites per day, respectively). In general, the response of wallabies to changes in herbage availability is similar to domestic ruminants, although wallabies may be able to graze for longer each day than ruminants.
The date of spawning in populations of the Common frog (Rana temporaria) from different altitudes in northern England
Authors: Beattie R. C.
Published: August 2010

A series of ponds in the Wear Valley in northern England, ranging in altitude from 46 to 838 m, were visited regularly over a four‐year‐period, and a record was kept of the dates on which spawn from the Common frog, Rana temporaria, was first seen in each of the ponds. On average. spawning was delayed by six days for every 100 m increase in altitude. The date of spawning at each of the ponds was fairly consistent from year to year; only in 1974 was the date of spawning noticeably different from other years. A theory was proposed which could account for the variation in the date of spawning with altitude and the annual variation in the date of spawning, observed in the present study. It is proposed that frogs from nothern England become sensitive to environmental temperature in the middle of February and emerge in the spring after experiencing a temperature‐sum of 106 degree(C)‐days. The onset of temperature sensitivity is probably initiated by a circannual endogenous rhythm. The time at which the rhythm switches on the temperature‐sensing mechanism in frogs probably varies in different populations, and may well be locally adapted. For spawning to follow emergence, a certain minimum water temperature may be required. In the present study, most frogs in the wild spawned when the water temperature in the ponds was above 7°C, but frogs could spawn at 3·1°C. Alternative theories for the control of emergence and spawning are also discussed.
The effect of melatonin on the seasonal embryonic diapause of the Bennett's wallaby (Macropus rufogriseus rufogriseus)
Authors: Loudon A. S. I. , Curlewis J. D. , English J.
Published: August 2010

In seasonally breeding mammals, the hormone melatonin, produced at night by the pineal gland, is known to be important in transducing the effect of photoperiod in timing reproduction. In the Bennett's wallaby, an unimplanted unilaminar blastocyst is held in a state of seasonal diapause from mid‐winter to mid‐summer. Here we show that an implant of the hormone melatonin rapidly terminates seasonal diapause in this species. Blastocyst reactivation is not accompanied by a significant reduction in levels of the hormone prolactin, thereby refuting earlier suggestions that this hormone is responsible for maintaining seasonal embryonic diapause.
The early development of the quail (Coturnix c. japonica) furcula reconsidered
Authors: Russell A. P. , Joffe D. J.
Published: August 2010

Although the avian furcula is generally regarded as a dermal bone, this view was challenged by Lansdown (1968a), who postulated that it is a cartilage bone. His reinterpretation was predicated upon histochemical data, derived from embryological observations made on the Japanese quail, and is deserving of further investigation as it bears importantly upon the interpretation of the homology of the furcula, and upon aspects of avian phylogeny and the origin of the flight apparatus.

Employing the same investigative methods as Lansdown (1968a), together with additional techniques, his interpretations have been reconsidered and no support for his suggestions has been found. The furcula of the quail, instead, has the early developmental characteristics of a typical dermal bone and conforms with the developmental details seen in the chicken.
Variation in plumage colour of the Great tit Parus major in relation to habitat, season and food
Authors: Slagsvold T. , Lifjeld J. T.
Published: August 2010

The plumage colour of nestling and adult Great tits Parus major major L. was studied at Trondheim (63 °N, 10 °E), Norway. Nestlings reared in deciduous woodland were yellower than those reared in coniferous woodland, those reared in 1983 were yellower than those in 1982, and the later in the breeding season they were reared the more yellow they were. Furthermore, adults were yellower than nestlings, and for both groups the males were yellower than the females. Experimental interchange of eggs between nests showed that the variation in plumage colour observed between broods was related primarily to the food and not to genetic differences. Sampling, by the neck‐collar method, of the food brought by the parent birds showed that the yellower nestlings received a greater proportion of lepidopteran larvae, in particular greenish‐coloured ones, than did the nestlings with a paler plumage. A speculation is whether or not the variation in plumage colour has some adaptive value (viz. background matching).

In avian systematics, plumage coloration has been used to distinguish and describe subspecies. The present study shows that such a classification should only be made with certain reservations, until possible variation in the food quality of the subspecies is known to have no influence on plumage coloration.
Relative size of the foot of two species of Littorina on a rocky shore in Wales
Authors: Grahame J. , Mill P. J.
Published: August 2010

Populations of the gastropods Littorina rudis and L. arcana on the rocky shore at Westdale, Pembroke, South Wales, have been investigated. Foot area has been related to shell length. It is shown that there are differences in the areas of the expanded foot of different groups of snails: those from more exposed sites have a relatively larger foot. Littorina arcana achieves the greatest foot area of all, and it extends on to the most exposed rocks investigated, where L. rudis is absent. It is suggested that this may be important in ecological separation of the two species. It is noted that there is still uncertainty over the taxonomic identity of what is referred to here as ‘Littorina rudis’, and further work is in progress.
A comparison of the fecundities of two species of toad (Bufo bufo and B. calamita) from different habitat types in Britain
Authors: Banks B. , Beebee T. J. C.
Published: August 2010

The fecundities of Natterjack toads, Bufo calamita, on a Cumbrian dune system and a relict heathland site in Hampshire were compared and contrasted with the fecundity of Common toads, B. bufo, on the Cumbrian dunes. For both species, fecundity was positively correlated with length, while in B. calamita length was also correlated with size of eggs produced, and age of the female. Bufo calamita was found to invest more energy exponentially in egg production with increasing length, and therefore age. This species also laid more than twice as many eggs as comparably‐sized female B. bufo, and some probably produced two clutches of spawn per year in southern England. The enhanced fecundity of the species was believed to be an adaptation to living in areas with unpredictable spawning sites. Small female B. bufo on the dunes appeared to put more energy into egg production when small than individuals of the same species on other habitat types in Britain, possibly as a result of reduced life expectancy on the dune habitat. There was a link between old age and the production of non‐viable spawn in B. calamita, and males of this species which spawned at the end of the prolonged breeding season were found to have reduced fertilization efficiency when spawning on consecutive evenings.
The annual reproductive cycle of the Smooth newt (Triturus vulgaris) in England
Authors: Verrell P. A. , Halliday T. R. , Griffiths M. L.
Published: August 2010

Newts were collected throughout the year from both breeding ponds and terrestrial sites and were weighed, measured and dissected; in males, the testes were examined histologically. Smooth newts show post‐nuptial gametogenesis such that, during late summer and autumn they are producing mature gametes for the following year's breeding season. In males, the testes are at their smallest size during the spring, when they consist mostly of immature sperm cysts and evacuated tissue, mature sperm having been evacuated into the vasa deferentia during the newts' migration to water. Evacuated testicular tissue is glandular in function and there is evidence that secretions from this tissue control the development of secondary sexual characters: the dorsal crest, fringes of skin on the toes and the dorsal cloacal gland. In both sexes, fat body and liver weights are lowest in the spring and increase in the autumn. In females, oocytes vary in size, depending on the amount of yolk they contain. Only the larger oocytes are laid in a current breeding season, the smaller ones being retained and yolked in late summer and autumn. In both sexes, measures of fecundity (testis size in males, oocyte number in females) are strongly correlated with body size. The finding that male newts have a finite supply of sperm during the breeding season leads to an interpretation of various aspects of male courtship behaviour. These are adaptations for conserving sperm and allocating it to courtship encounters in a way likely to promote male reproductive success.
Sexual dimorphism in wing and tail length as shown by the Swallow Hirundo rustica
Authors: Bańbura Jerzy
Published: August 2010

In both sexes of Hirundo rustica two metric traits are significantly different. One of these traits, tail length, shows a positive correlation between mates and a negative correlation with the date of first egg laying. On the other hand, wing lengths are not significantly related in any of the corresponding tests. Similar relations were recorded both for all analysed birds and for at least two‐year‐old individuals. It is suggested that sexual selection, as proposed by Darwin (1871) for monogamous birds, is responsible for sexual dimorphism in the tail length of the Swallow. It seems that intersexual difference in wing length could be a result of such mechanisms as stabilizing the body sizes of males and females at different energetically optimum levels by natural selection.
Developmental constraints on limb growth in domestic and some wild canids
Authors: Wayne Robert K.
Published: August 2010

The domestic dog varies remarkably in limb size. Presumably, such differences in limb size stem from inequities in postnatal specific growth rate. I test this hypothesis by examining the postnatal growth of limb bones (40–250 days post‐partum) in four dog breeds of dramatically different adult size; Lhasa Apso, Cocker Spaniel, Labrador Retriever and Great Dane. The results show that the limb bones of these four breeds have similar specific growth rates throughout most of postnatal development. Thus, proportionate differences in limb bone length are established during perinatal growth (0–40 days post‐partum) or before birth.

Comparisons of postnatal growth in the Great Dane and two wild canids of dramatically different leg length, the Bush dog (Speothos venaticus) and the Maned wolf (Chrysocyon brachyurus) also show a near congruency of specific growth rate curves. However, despite these similarities, the adult limb proportions of small dogs and small wild canids are different. Dogs also differ from wild canids in the relative variability of gestation time. All dogs have a similar gestation period of 60–63 days which is independent of birth weight, whereas the two are directly related in wild canids. I suggest that small dogs may differ in limb proportions from small wild canids because the latter have a shorter gestation period. Thus, the relative invariability of gestation time in domestic dogs may act as a fundamental constraint on their morphologic variability.
Egg production in the Common toad, Bufo bufo
Authors: Reading C. J.
Published: August 2010

The number and size of eggs produced by the Common toad (Bufo bufo) was investigated at a site in southern England. There was a trend within the population as a whole for egg weight, egg number and ovary weight to increase with female size, as defined by body length and body weight. However, with use of partial correlation analysis to remove the effects of female size from the data, some of these trends changed. Thus, for females of the same size, although egg number increased with ovary weight, no significant correlation was found between egg weight and ovary weight whilst egg weight became negatively correlated with egg number. The possible significance of variation in egg weight on tadpole survival and female reproductive success is discussed.
Materialism and conspicuous consumption in China: a cross‐cultural examination
Authors: Podoshen Jeffrey S. , Li Lu , Zhang Junfeng
Published: August 2010

With the growing rise in consumer spending and economic power in Asian societies, it is increasingly important to explore the implications of these developments on consumer culture. This cross‐cultural study first discusses the rise of materialism and conspicuous consumption in post‐revolution China then examines differences in these phenomena between young adult consumers, aged 18–35, living in urban China and the United States. Utilizing survey data from over 600 respondents, significant differences were found in both materialism and conspicuous consumption, with Chinese young adults scoring higher in both variables. The findings show, that compared with past comparative studies, it appears both materialism and conspicuous consumption are on the rise among urban Chinese consumers.
The role of endogenous serotonin in methamphetamine‐induced neurotoxicity to dopamine nerve endings of the striatum
Authors: Thomas David M. , Pérez Mariana Angoa , Francescutti‐Verbeem Dina M. , Shah Mrudang M. , Kuhn Donald M.
Published: August 2010

J. Neurochem.(2010)115, 595–605.

Methamphetamine (METH) is a neurotoxic drug of abuse that damages the dopamine (DA) neuronal system in a highly delimited manner. The brain structure most affected by METH is the striatum where long‐term DA depletion and microglial activation are maximal. Endogenous DA has been implicated as a critical participant in METH‐induced neurotoxicity, most likely as a substrate for non‐enzymatic oxidation by METH‐generated reactive oxygen species. The striatum is also extensively innervated by serotonin (5HT) nerve endings and this neurochemical system is modified by METH in much the same manner as seen in DA nerve endings (i.e., increased release of 5HT, loss of function in tryptophan hydroxylase and the serotonin transporter, long‐term depletion of 5HT stores). 5HT can also be modified by reactive oxygen species to form highly reactive species that damage neurons but its role in METH neurotoxicity has not been assessed. Increases in 5HT levels with 5‐hydroxytryptophan do not change METH‐induced neurotoxicity to the DA nerve endings as revealed by reductions in DA, tyrosine hydroxylase and dopamine transporter levels. Partial reductions in 5HT withp‐chlorophenylalanine are without effect on METH toxicity, despite the fact thatp‐chlorophenylalanine largely prevents METH‐induced hyperthermia. Mice lacking the gene for brain tryptophan hydroxylase 2 are devoid of brain 5HT and respond to METH in the same manner as wild‐type controls, despite showing enhanced drug‐induced hyperthermia. Taken together, the present results indicate that endogenous 5HT does not appear to play a role in METH‐induced damage to DA nerve endings of the striatum.
Are Suicidal Phenomena in Children Different to Suicidal Phenomena in Adolescents? A Six‐Year Review
Authors: Sarkar Manas , Byrne Patricia , Power Lorna , Fitzpatrick Carol , Anglim Margo , Boylan Carole , Morgan Sophia
Published: August 2010

Background:  There has been little published about the nature and frequency of suicidal phenomena in children compared to that of adolescents.

Method:  Standardised information on all presentations with suicidal phenomena to the Children’s University Hospital, Dublin from 2002 to 2008 were retrospectively analysed from a centralised database.

Results:  During the time period of the study, 401 young people presented for assessment, of whom 21.9% (N = 88) were under 12 years of age. Children differed from adolescents in terms of gender distribution, method of self‐harm, and risk factors present.

Conclusion:  Children under 12 are capable of displaying suicidal phenomena and differ considerably to adolescents in this regard.
Presidential Address: The Visible or Invisible Hand? The Balance Between Markets and Regulation in Agricultural Policy
Authors: Blandford David
Published: August 2010

The recent crisis in global financial markets has brought into question reliance on markets to determine the conduct of economic affairs and generated pressure for greater regulation and government control. Neither a neoliberal nor a neoregulatory approach is likely to be able to solve pressing problems affecting agriculture and natural resources, such as a deterioration in environmental quality and the challenge of climate change. To find solutions we need to employ a more realistic behavioural model than that typically used in economic analysis, and to recognise the key role played by values in individual and collective decision making. A more devolved approach to policy formation based on collective action seems to offer the greatest chance of success. More effort needs to be directed to understanding the drivers and processes of collective decision making, and how it can be harnessed to address pressing policy issues.
Recovery and Management Committees for Lion Tamarins: Partnerships in Conservation Planning and Implementation
Authors: Kleiman Devra G. , Mallinson Jeremy J. C.
Published: August 2010

Four international recovery and management committees act as official technical advisors to the Brazilian federal environmental agency—the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis—with respect to the conservation and management of both the in situ and ex situ populations of the endangered lion tamarins ( Leontopithecus). The committees promote lion tamarins as “flagship” species, the ultimate intent being the preservation of the unique Atlantic rain forest (Mata Atlântica) ecosystem and its many endemic plants and animals. We summarize the history, organization, structure, and functioning of these oversight management committees and their current role in guiding, motivating, and focusing conservation efforts for the Mata Atlântica of Brazil and the four endangered Leontopithecus species therein. We discuss the role of science in conservation planning for the species, funding mechanisms, the decision‐making process, conflicts and their resolution, and criteria used for evaluating success. The benefits of this particular species recovery process include the establishment of collaborative partnerships between the Brazilian government and a multitude of individuals and organizations and the use of multidisciplinary, semi‐autonomous teams to implement conservation activities. The major limitation of the management committees is their lack of a formal budget and permanent staff.

Comites de Recuperación y Manejo de León Tamarins: Colaboraciones en Planeación e Implementación de la Conservación

Cuatro comités de recuperación y manejo actúan como asesores técnicos del Instituto Brasileño del Medio Ambiente y Recursos Naturales Renovables en lo concerniente a la conservación y manejo de poblaciones del león tamarins ( Leontopithecus) tanto in situ como ex situ. Los comités promueven al león tamarins como una especie “bandera”, con la intensión de preservar el peculiar ecosistema de bosque lluvioso del Atlántico (Mata Atlântica) así como sus plantas y animales endémicos. Resumimos la historia, organización, estructura y funcionamiento de estos comites de manejo, así como su papel actual en la conducción, motivación y enfoque de los esfuerzos de conservación del Mata Atlântica del Brasil y de las cuatro especies amenazadas de Leontopithecus. Discutimos el papel de la ciencia en la planeación de la conservación de las especies, los mecanismos de financiamiento, los procesos de toma de decisiones, los conflictos y sus soluciones y los criterios empleados para la evaluación de los avances. Los beneficios del proceso de recuperación de esta especie en particular incluyen el establecimiento de trabajo en colaboración entre el gobierno de Brasil y una gran cantidad de individuos y organizaciones, además del empleo de grupos multidisciplinarios semiautónomos para la implementación de actividades de conservación. Las mayores limitantes para los comités de manejo han sido la carencia de un presupuesto formal y de trabajadores permanente.
Geographic Isolation of Hector’s Dolphin Populations Described by Mitochondrial DNA Sequences
Authors: Pichler F. B. , Dawson S. M. , Slooten E. , Baker C. S.
Published: August 2010

To describe the genetic structure of Hector’s dolphin (Cephalorhynchus hectori) populations, we used the polymerase chain reaction to amplify and sequence a 360 base‐pair fragment of the mitochondrial DNA control region from 34 beachcast or gillnet‐caught specimens. Variation in these sequences identified 11 distinct haplotypes differing from one another by 0.28–1.67% and by an average of 4.47% from the closely related Commerson’s dolphin. The genealogical relationship of these haplotypes showed a strong concordance with the geographic origins of the samples. An analysis of variance modified for molecular data showed that 74% of the sequence variation could be explained by the three primary sampling regions: the North Island, the west coast of the South Island, and the east coast of the South Island. Such a marked segregation of maternal lineages across a small geographic range is unusual among cetaceans. The low rate of female dispersal, as indicated by this mitochondrial DNA structure, could increase the vulnerability of local populations to extinction due to fisheries‐related mortality.

Aislamiento Geográfico de Poblaciones del Delfin de Hector Descritas por Secuencias Mitocondriales de ADN

Para describir la estructura genética del delfín de Hector (Cephalorhynchus hectori), utilizamos la reacción de polimerasa en cadena para amplificar y secuenciar un fragmento de la región control del ADN‐mitocondrial de 360 pares de bases provenientes de 34 especímenes varados en playas o capturados en redes agalleras. La variación de las secuencias identificaron 11 haplotipos distintivos difiriendo entre ellos por un 0.28–1.67% y por un promedio de 4.47% del relativamente cercano delfin de Commerson. La relación genealógica de estos haplotipos muestran una fuerte concordancia con los origenes geográficos de las muestras. Un análisis de varianza modificado para datos moleculares mostró que 74% de la variación de las secuencias puede ser explicada por tres regiones de muestreo primarias: la isla del norte, la costa oeste de la isla del sur y la costa este de la isla del sur. Esta segregación tan marcada de linajes maternales a lo largo de un rango geográfico pequeño es inusual en cetáceos. La baja tasa de dispersión de hembras, indicada por la estructura del DNA mitocondrial, podría incrementar la vulnerabilidad de las poblaciones locales a la extinción debido a la mortalidad relacionada con pesquerías.
Phylogenetic Distinctiveness of a Threatened Aquatic Turtle (Ster nother us depressus)
Authors: Walker Deette , Ortí Guillermo , Avise John C.
Published: August 2010

The musk turtle (Sternotherus minor) is common throughout the southeastern United States. In 1955 a morphologically atypical form confined to the Black Warrior River System in Alabama was discovered and accorded full species status asS. depressus, the “flattened musk turtle.” Questions remain about the taxonomic status and evolutionary history of the flattened musk turtle because (1) the geographic distribution ofS. depressusis nested within the range ofS. minor; (2) the flattened shell might be a recently evolved anti‐predator adaptation; and (3) reports exist of intergrades betweenS. depressusandS. minor. We generated and employed sequence data from mitochondrial DNA to address the phylogenetic distinctiveness and phylogeographic position ofS. depressusrelative to all other musk and mud turtles (Kinosternidae) in North America. The flattened musk turtle forms a well‐supported monophyletic group separate fromS. minor. Genetic divergence observed betweenS. depressusand geographic populations ofS. minoris no less than that distinguishing many kinosternid congeners from one another. These molecular genetic findings bolster rationale for the taxonomic recognition ofS. depressusand, hence, for special efforts to protect this federally threatened species.

Distintividad Filogenética de una Tortuga Acuática Amenazada (Sternotherus depressus)

Las tortugas acuáticas (“musk turtles”) de la especieSternotherus minor( familia Kinosternidae) están ampliamente distribuidas en la región sudeste de los Estados Unidos de Norteamérica. En 1955, una variedad de musk turtle morfológicamente atípica, con el caparazón notoriamente comprimido y restringida a la cuenca del río Black Warrior en Alabama, fue descrita y asignada a una especie nueva,S. depressus(“flattened musk turtle”). Posteriormente, el origen evolutivo y el estatus taxonómico de esta nueva especie han sido cuestionados debido a: (1) su restringida distribución geográfica esta anidada dentro del rango de distribución deS. minor; (2) El caparazón aplanado podría ser una adaptación anti‐depredador recientemente evolucionada; y (3) existen reportes de morfologías intermedias entreS. depressusyS. minor. En el presente trabajo se emplean secuencias de ADN mitocondrial para evaluar la identidad genética, posición filogenética, y distribución filogeográfica deS. depressusen relación a las demás especies norteamericanas de la familia Kinosternidae. Los datos obtenidos confirman la identidad deS. depressuscomo una especie separada genéticamente de la poblaciones locales deS. minor, y de las otras especies de la familia Kinosternidae. Estos resultados sugieren el reconocimiento taxonómico deS. depressusy justifican los esfuerzos conservacionistas para proteger esta especie amenazada.
Evaluating the Biotic Integrity of Watersheds in the Sierra Nevada, California
Authors: Moyle Peter B. , Randall Paul J.
Published: August 2010

We developed a watershed index of biotic integrity that used whole watershed variables for metrics rather than site‐specific variables. We used the index to evaluate the biological health of 100 watersheds in the Sierra Nevada of California. The index scores, which were based on various measures of distribution and abundance of native fish and frogs, indicated that 7 of the watersheds were in excellent condition (high biotic health), 36 were in good to very good condition, 48 were in fair condition, and 9 were in poor condition. The biggest factors contributing to low index scores were large dams and introduced fishes, although measures of road density and indicators of intensity of use of terrestrial habitats were also important. Large areas of the Sierra Nevada that were once fishless now contain trout in most waters, anadromous fishes are excluded from many streams from which they were once abundant, assemblages of native fishes have been disrupted, and ranid frogs have been extirpated from many areas. All watersheds in the Sierra Nevada have thus experienced loss of biotic integrity, but some have suffered much less than others. Evaluations of the biotic integrity of watersheds over wide regions can help managers set priorities for watershed‐oriented systems of aquatic conservation and provide starting places for more‐intensive studies.

Evaluación de la Integridad Biótica de Cuencas Acuíferas en la Sierra Nevada, California

Un indice de cuencas de integridad biótica fue desarrollado, el cual utilizó variables paramétricas en vez de variables de lugar específico. El índice fue utilizado para evaluar la salud biológica de cien cuencas en la Sierra Nevada de California. El muestreo, el cual fue basado en varias medidas de disribución y abundancia de peces nativos y ranas indicaron que siete de las cuencas estaban en excelente condición (salud biótica), treinta y seis estaban de buena a muy buena condición, cuarenta y ocho estaban en favorable condición y nueve estaban en mala condición. Los factores más grandes que contribuyeron al bajo muestreo fueron represas grandes y peces introducidos, aunque medidas de densidad de carreteras, indicadores de intensidad del uso de comunidades terrestres, fueron también importantes. Grandes areas de la Sierra Nevada que no tenían peces ahora contienen trucha en la mayoria de sus aguas, peces anadromos están excluidos de muchos arroyos, en los cuales ellos fueron una vez abundantes; comunidades de peces nativos han sido interrumpidas, y ranas de la familia ranidae han sido exterminadas de muchas areas. Todas las cuencas en la Sierra Nevada, por lo tanto, han experimentado pérdida de integridad biótica, pero algunas han experimentado menos pérdida que otras. Evaluaciones de la integridad biótica de cuencas sobre regiones extensas pueden ayudar a establecer prioridades para un sistema de conservación acuática y proveer información básica para estudios más intensos.
Incentives for Biological Conservation: Costa Rica's Private Wildlife Refuge Program
Authors: Langholz Jeff , Lassoie James , Schelhas John
Published: August 2010

Abstract: The alarming pace of tropical biodiversity loss requires development of innovative approaches for in situ biodiversity conservation. Incentive‐based approaches have emerged as one possible option. We interviewed 68 private nature reserve owners to learn more about one of Costa Rica's incentive programs. The interview group included all reserve owners participating in the government's Private Wildlife Refuge Program (n = 22) and a control group of nonparticipating owners (n = 46). Quantitative and qualitative data led to seven main conclusions on the use of incentive programs: (1) a developing country can expand and enhance its formal park system through conservation incentives; (2) insufficient promotion, and resulting information gaps, can prevent an incentive program from realizing its full potential; (3) landowners enter a program not only in response to the intended incentive package, but also for several powerful and hidden incentives such as publicity and marketing purposes; (4) underutilization of official incentives by participants, in part due to sporadic delivery of incentives by the government, can undermine program effectiveness; (5) biodiversity protection goals can be accomplished by means of a wide range of incentives; (6) programs that require only a short‐term commitment by landowners can still lead to long‐term biodiversity protection; and (  7) a program can produce unanticipated negative consequences at the national level, including putting conservation at odds with social justice. These and other lessons on the use of incentives should be of interest wherever biodiversity is threatened, wherever new conservation partners are being sought, and wherever incentive‐based approaches are being considered.
Bushmeat Markets on Bioko Island as a Measure of Hunting Pressure
Authors: Fa Julia E. , Yuste Juan E. Garcia , Castelo Ramon
Published: August 2010

Abstract: Counts of the number of animal carcasses arriving at Malabo market, Bioko Island, Equatorial Guinea, were made during two, 8‐month study periods in 1991 and 1996. Comparisons of the availability and abundance of individual species between years showed that more species and more carcasses appeared in 1996 than in 1991. In biomass terms, the increase was significantly less, only 12.5%, when compared with almost 60% more carcasses entering the market in 1996. A larger number of carcasses of the smaller‐bodied species (i.e., rodents and the blue duiker [Cephalophus monticola] ) were recorded in 1996 than in 1991. Although an additional four species of birds and one squirrel were recorded in 1996, these were less important in terms of their contribution to biomass or carcass numbers. Concurrently, there was a dramatic reduction in the larger‐bodied species, Ogilby's duiker (C. ogilbyi) and seven diurnal primates. We examined these changes, especially the drop in the number of larger animals. We considered the possible following explanations: (1) the number of hunters dropped either because of enforced legislation or scarcity of larger prey; (2) a shift in the use of hunting techniques occurred (   from shotguns to snares); or (3) consumer demand for primate and duiker meat dropped, which increased demand for smaller game. Our results suggest that the situation in Bioko may be alarmingly close to a catastrophe in which primate populations of international conservation significance are being hunted to dangerously low numbers. Although there is still a need for surveys of actual densities of prey populations throughout the island, working with the human population on Bioko to find alternatives to bushmeat is an urgent priority.
Bat‐ and Bird‐Generated Seed Rains at Isolated Trees in Pastures in a Tropical Rainforest
Authors: Galindo‐González Jorge , Guevara Sergio , Sosa Vinicio J.
Published: August 2010

Abstract: Bats are abundant and effective seed dispersers inside the forest, but what happens when a forest is fragmented and transformed into pasture? The landscape at Los Tuxtlas, Mexico, originally rainforest, is greatly fragmented and covered with pastures. We analyzed the seed rains produced by frugivorous bats and birds under isolated trees in pastures in the fragmented landscape and the contribution of this process to vegetational recovery. We surveyed bats and obtained fecal samples under isolated trees in pastures. We also collected seed rain below the canopy of 10 isolated Ficus trees, separating nocturnally dispersed seeds from diurnally dispersed seeds. We caught 652 bats of 20 species; 83% of captures were frugivores. The most abundant species were Sturnira lilium (48%), Artibeus jamaicensis (18%), Carollia perspicillata (12%), and Dermanura tolteca (11%). Fecal samples contained seeds of 19 species in several families: Piperaceae (50%), Moraceae (25%), Solanaceae (12%), Cecropiaceae (10%), and others (3%). Sturnira lilium was the most important disperser bat in pastures. Seed rain was dominated by zoochorous species (89%). We found seed diversity between day and night seed captures to be comparable, but we found a significant interaction of disperser type (  bird or bat) with season. Seven plant species accounted for 79% of the seed rain: Piper auritum (23%), Ficus (  hemiepiphytic‐strangler tree) spp. (17%), Cecropia obtusifolia (10%), P. amalago (10%), Ficus (  free‐standing tree) spp. (8%), P. yzabalanum (6%), and Solanum rudepanum (5%). Bats and birds are important seed dispersers in pastures because they disperse seeds of pioneer and primary species (trees, shrubs, herbs, and epiphytes), connect forest fragments, and maintain plant diversity. Consequently, they might contribute to the recovery of woody vegetation in disturbed areas in tropical humid forests.
Heavy Extinctions of Forest Avifauna in Singapore: Lessons for Biodiversity Conservation in Southeast Asia
Authors: Castelletta Marjorie , Sodhi Navjot S. , Subaraj R.
Published: August 2010

Abstract: The consequences of rapid rainforest clearance on native avifauna are poorly understood. In Southeast Asia, Singapore, a newly developing country, has had 95% of its native lowland rainforest cleared. Most of the rainforest was lost in the mid‐ to late‐nineteenth century. We compared avifauna checklists from 1923, 1949, and 1998 to determine the extent of extinctions between 1923 and 1998 in Singapore. Of 203 diurnal bird species, 65 were extirpated in Singapore in the past 75 years. Four of these species were nonforest‐ dependent species, whereas 61 (94%) were forest bird species dependent on the primary or old secondary forest to survive. Twenty‐six forest bird species became extinct between 1923 and 1949, whereas 35 forest species disappeared after 1949. We compared the body lengths, feeding guilds, and vertical feeding zones between extinct and extant forest bird species to determine whether extinction patterns were dependent on these characteristics. Larger forest bird species went extinct between 1923 and 1949. Body sizes, however, did not affect the loss of forest bird species between 1949 and 1998. We observed high losses of insectivorous birds; the insectivore‐carnivore and insectivore‐granivore guilds lost> 80% of the species present in 1923. The highest losses were among birds that fed in the canopy. None of the forest bird species are currently common (>100 individuals/species) within Singapore. Our study shows that more than half the forest avifauna became locally extinct after extensive deforestation. Based on this fact, the countries within Southeast Asia should reconsider their heavy deforestation practices.
Population Size, Genetic Variation, and Reproductive Success in a Rapidly Declining, Self‐Incompatible Perennial (Arnica montana) in The Netherlands
Authors: Luijten Sheila H. , Dierick Angelo , Gerard J. , Oostermeijer B. , Raijmann Léon E. L. , Den Nijs Hans C. M.
Published: August 2010

Abstract:Arnica montanais a rare and rapidly declining, self‐incompatible plant species. In 26 populations in The Netherlands we investigated the relationship between population size and genetic variation using allozyme markers. Genetic variation was low inA. montana(  He= 0.088). There were positive correlations between population size and the proportion of polymorphic loci, the number of effective alleles, and expected heterozygosity, but not with observed heterozygosity. There was a significantly positive correlation between population size and the inbreeding coefficient. Generally, small populations showed heterozygote excess, which decreased with increasing population size. Possibly, the heterozygous individuals in small populations are survivors from the formerly larger populations with relatively high fitness. TheFstatistics showed a moderately high level of differentiation among populations (  FST= 0.140 ± 0.02), implying a low level of gene flow. For three out of four allozyme loci, we found significant inbreeding (  FIS= 0.104 ± 0.03). Only 14 of 26 populations were in Hardy‐Weinberg equilibrium at all four polymorphic loci. In a subset of 14 populations of various size, we investigated natural seed production and offspring fitness. Population size was positively correlated with seed set, seedling size, number of flowering stems and flowerheads, adult survival, and total relative fitness, but not with the number of florets per flowerhead, germination rate, or the proportion of germination. Offspring performance in the greenhouse was not associated with genetic diversity measured on their mothers in the field. We conclude that the fitness of small populations is significantly reduced, but that there is as yet no evidence that this was caused by inbreeding. Possibly, the self‐incompatibility system ofA.montanahas been effective in reducing selfing rates and inbreeding depression.
Population Variability and Extinction Risk
Authors: Vucetich John A. , Waite Thomas A. , Qvarnemark Linda , Ibargüen Siri
Published: August 2010

Abstract: Population models generally predict increased extinction risk (ER) with increased population variability (  PV  ), yet some empirical tests have provided contradictory findings. We resolve this conflict by attributing negative measured relationships to a statistical artifact that arises because PV tends to be underestimated for populations with short persistence. Such populations do not go extinct quickly as a consequence of low intrinsic variability; instead, the measured variability is low because they go extinct so quickly. Consequently, any underlying positive relationship between PV and ER tends to be obscured. We conducted a series of analyses to evaluate this claim. Simulations showed that negative measured relationships are to be expected, despite an underlying positive relationship. Simulations also identified properties of data, minimizing this bias and thereby permitting meaningful analysis. Experimental data on laboratory populations of a bruchid beetle (Callosobruchus maculatus) supported the simulation results. Likewise, with an appropriate statistical approach (Cox regression on untransformed data), reanalysis of a controversial data set on British island bird populations revealed a significant positive association between PV and ER (p = 0.03). Finally, a similar analysis of time series for naturally regulated animal populations revealed a positive association between PV and quasiextinction risk (p < 0.01). Without exception, our simulation results, experimental findings, reanalysis of published data, and analysis of quasiextinction risk all contradict previous reports of negative or equivocal relationships. Valid analysis of meaningful data provides strong evidence that increased population variability leads to increased extinction risk.
Using Logistic Regression to Analyze the Sensitivity of PVA Models: a Comparison of Methods Based on African Wild Dog Models
Authors: Cross Paul C. , Beissinger Steven R.
Published: August 2010

Abstract:We used logistic regression as a method of sensitivity analysis for a stochastic population viability analysis model of African wild dogs (  Lycaon pictus) and compared these results with conventional sensitivity analyses of stochastic and deterministic models. Standardized coefficients from the logistic regression analyses indicated that pup survival explained the most variability in the probability of extinction, regardless of whether or not the model incorporated density dependence. Adult survival and the standard deviation of pup survival were the next most important parameters in density‐dependent simulations, whereas the severity and probability of catastrophe were more important during density‐independent simulations. The inclusion of density dependence decreased the probability of extinction, but neither the abruptness nor the inclusion of density dependence were important model parameters. Results of both relative sensitivity analyses that altered each parameter by 10% of its range and life‐stage‐simulation analyses of deterministic matrix models supported the logistic regression results, indicating that pup survival and its variation were more important than other parameters. But both conventional sensitivity analysis of the stochastic model which changed each parameter by 10% of its mean value and elasticity analyses indicated that adult survival was more important than pup survival. We evaluated the advantages and disadvantages of using logistic regression to analyze the sensitivity of stochastic population viability models and conclude that it is a powerful method because it can address interactions among input parameters and can incorporate the range of parameter variability, although the standardized regression coefficients are not comparable between studies. Model structure, method of analysis, and parameter uncertainty affect the conclusions of sensitivity analyses. Therefore, rigorous model exploration and analysis should be conducted to understand model behavior and management implications.