Parataxonomía: un test utilizando escarabajos

The present study examines the utility of parataxonomic sorting (groupings of similar individuals, categorized by non–experts, relying on features of external morphology) using data from a study of beetle communities in four forest habitats in Nova Scotia, Canada. Alpha diversity and the Shannon–Weaver, Simpson, Berger–Parker, and Brillouin indices of diversity, derived from both taxonomic species and parataxonomic units, are compared and yield identical habitat rankings. Beta diversity rankings derived from both data sets do not differ although they produce slightly different rankings. The Elateridae, Curculionidae, Cantharidae, and Staphylinidae had particularly large numbers of "lumping" and "splitting" errors. Although the overall gross sorting error was only 14%, individual families of beetles had errors between 0% and 200% with an average error of 38%. The limitations of the parataxonomic approach are discussed; both in regard to the practical application of the concept, as well its theoretical basis. We note the spillover of this discourse to the subject of what constitutes a species and observe that this discussion has been misplaced due to the unfortunate confusion of the two usages of the term "morphospecies".El presente estudio examina la utilidad de la ordenación parataxonómica (agrupación de individuos similares, categorizados por aficionados, basada en caracteres morfológicos externos) usando los datos de un estudio de comunidades de escarabajos de cuatro hábitats forestales de Nueva Escocia, Canadá. Se comparan la diversidad alfa y los índices de diversidad de Shannon–Weaver, Simpson, Berger–Parker y Brillouin, obtenidos tanto de especies taxonómicas como de unidades parataxonómicas, dando como resultado rankings de hábitats idénticos. Los rankings de diversidad beta procedentes de ambas series de datos no se diferencian, aunque arrojan rankings ligeramente distintos. Los Elateridae, Curculionidae, Cantharidae y Staphylinidae presentaban gran cantidad de errores de "agrupación" y "escisión". Aunque el error de clasificación bruto global era tan solo del 14%, algunas familias de escarabajos presentaban errores de entre el 0 y el 200%, con un error medio del 38%. Se discuten las limitaciones del planteamiento parataxonómico; tanto en lo que hace referencia a la aplicación práctica del concepto, como a su base teórica. Esta discusión nos lleva al tema de en qué consiste una especie y nos permite ver como esta discusión ha sido mal enfocada debido a la desafortunada confusión de los dos usos del término "morfoespecie"

Parataxonomy: a test case using beetles

The present study examines the utility of parataxonomic sorting (groupings of similar individuals, categorized by non-experts, relying on features of external morphology) using data from a study of beetle communities in four forest habitats in Nova Scotia, Canada. Alpha diversity and the Shannon-Weaver, Simpson, Berger-Parker, and Brillouin indices of diversity, derived from both taxonomic species and parataxonomic units, are compared and yield identical habitat rankings. Beta diversity rankings derived from both data sets do not differ although they produce slightly different rankings. The Elateridae, Curculionidae, Cantharidae, and Staphylinidae had particularly large numbers of “lumping” and “splitting” errors. Although the overall gross sorting error was only 14%, individual families of beetles had errors between 0% and 200% with an average error of 38%. The limitations of the parataxonomic approach are discussed; both in regard to the practical application of the concept, as well its theoretical basis. We note the spillover of this discourse to the subject of what constitutes a species and observe that this discussion has been misplaced due to the unfortunate confusion of the two usages of the term “morphospecies”

Black Bear, Ursus americanus, Ecology on the Northeast Coast of Labrador

Twenty-three Black Bears (Ursus americanus) were captured, 20 were measured, marked and/or radio collared, in northeastern Labrador, between 1996 and 1997. Bears used sea ice for travel, coastal islands for denning, hunted adult Caribou (Rangifer tarandus), and were the possible cause of Moose (Alces alces) calf mortality. Body sizes were small, median weight of adult females was 48 kg, and the sex ratio for captured subjects was 1:1. Four of six radio-collared females gave birth during the winter of 1997, female reproductive histories suggest delayed sexual maturity. Den entry occurred between October and December 1996; spring emergence occurred between April and May 1997, with estimated denning period ranging from 148-222 days. Visual observations of habitat use by radio collared subjects (n = 10) were not tested statistically but suggest that barren areas are used nearly as much as forest. Location data from three GPS collars deployed on three adult females were analysed using Chi-square goodness-of-fit test with Bonferroni correction; two females appeared to prefer forest habitats (p < 0.05)

Effects of Ash Application on Cadmium Concentration in Small Mammals

In order to assess the effects of wood ash application to forests on small mammals, we collected bank voles (Clethrionomys glareolus ) and common shrews (Sorex araneus ) from a forest area in southern Finland. Part of the sample population was from sites that had been treated with ash 1.5 years earlier, part from untreated control sites. The ash increased the soil pH and gave an average cadmium load in soil of 44 g ha1.When comparing treated and control areas, we found slightly but significantly lower Cd concentrations in vole muscle, liver, and kidney from treated plots, whereas the Cd concentrations in shrew tissues were greater in animals from treated plots. In voles we detected an increase in Cd concentrations during the 45-d sampling period in treated and untreated plots. The relative weight of kidneys was greater from the ash-treated areas than untreated areas for both voles and shrews. The difference in Cd concentrations between the voles and shrews could be explained by the different food habits

Maternal investment in relation to sex ratio and offspring number in a small mammal – a case for Trivers and Willard theory?

Optimal parental sex allocation depends on the balance between the costs of investing into sons vs. daughters and the benefits calculated as fitness returns. The outcome of this equation varies with the life history of the species, as well as the state of the individual and the quality of the environment.We studied maternal allocation and subsequent fecundity costs of bank voles, Myodes glareolus, by manipulating both the postnatal sex ratio (all-male/all-female litters) and the quality of rearing environment (through manipulation of litter size by −2/+2 pups) of their offspring in a laboratory setting.We found that mothers clearly biased their allocation to female rather than male offspring regardless of their own body condition. Male pups had a significantly lower growth rate than female pups, so that at weaning, males from enlarged litters were the smallest. Mothers produced more milk for female litters and also defended them more intensively than male offspring.The results agree with the predictions based on the bank vole life history: there will be selection for greater investment in daughters rather than sons, as a larger size seems to be more influencial for female reproductive success in this species. Our finding could be a general rule in highly polygynous, but weakly dimorphic small mammals where females are territorial.The results disagree with the narrow sense Trivers & Willard hypothesis, which states that in polygynous mammals that show higher variation in male than in female reproductive success, high-quality mothers are expected to invest more in sons than in daughters

How Does Spatial Study Design Influence Density Estimates from Spatial Capture-Recapture Models?

When estimating population density from data collected on non-invasive detector arrays, recently developed spatial capture-recapture (SCR) models present an advance over non-spatial models by accounting for individual movement. While these models should be more robust to changes in trapping designs, they have not been well tested. Here we investigate how the spatial arrangement and size of the trapping array influence parameter estimates for SCR models. We analysed black bear data collected with 123 hair snares with an SCR model accounting for differences in detection and movement between sexes and across the trapping occasions. To see how the size of the trap array and trap dispersion influence parameter estimates, we repeated analysis for data from subsets of traps: 50% chosen at random, 50% in the centre of the array and 20% in the South of the array. Additionally, we simulated and analysed data under a suite of trap designs and home range sizes. In the black bear study, we found that results were similar across trap arrays, except when only 20% of the array was used. Black bear density was approximately 10 individuals per 100 km2. Our simulation study showed that SCR models performed well as long as the extent of the trap array was similar to or larger than the extent of individual movement during the study period, and movement was at least half the distance between traps. SCR models performed well across a range of spatial trap setups and animal movements. Contrary to non-spatial capture-recapture models, they do not require the trapping grid to cover an area several times the average home range of the studied species. This renders SCR models more appropriate for the study of wide-ranging mammals and more flexible to design studies targeting multiple species

Isotopic partitioning by small mammals in the subnivium

In the Arctic, food limitation is one of the driving factors behind small mammal population fluctuations. Active throughout the year, voles and lemmings (arvicoline rodents) are central prey in arctic food webs. Snow cover, however, makes the estimation of their winter diet challenging. We analyzed the isotopic composition of ever-growing incisors from species of voles and lemmings in northern Finland trapped in the spring and autumn. We found that resources appear to be reasonably partitioned and largely congruent with phylogeny. Our results reveal that winter resource use can be inferred from the tooth isotopic composition of rodents sampled in the spring, when trapping can be conducted, and that resources appear to be partitioned via competition under the snow.Peer reviewe

The Wernecke igneous clasts in Yukon, Canada: evidence for a Paleoproterozoic volcanic arc terrane at 1.7 Ga and its obduction onto ancestral North America

All observed Wernecke igneous clasts (WIC) occur within the 1.60 Ga Wernecke Breccias of Yukon, Canada. The clasts range up to 5.4 million m3 in volume, and comprise the 1.71 Ga Bonnet Plume River Intrusions (BPRI), the Slab volcanics, the Devil volcanics, and the Blackstone River megaclast. The WIC were not emplaced through the <1.64 Ga Wernecke Supergroup (WSG). The BPRI and Devil volcanics have a geochemical affinity with volcanic arcs. The Slab volcanics are more alkaline, like mantle plume or slab-window derived volcanoes. Sm-Nd isotopes indicate that magmas of the BPRI and Devil volcanics assimilated older basement rock. The WIC originated in a terrane that was obducted onto the WSG. Hydrothermal fluids brecciated these units, forming the Wernecke Breccias. WICs derived from the terrane foundered into these breccias to the level of the WSG and were metasomatized. The obducted terrane eroded entirely prior to deposition of the Pinguicula Group

High reliance on a diet of Moose (Alces americanus) by Eastern Coyotes (Canis latrans var.) in Cape Breton Highlands National Park, Nova Scotia, Canada

Eastern Coyote (Canis latrans var.) scats were collected along transects in Cape Breton Highlands National Park, Nova Scotia, Canada, from May 2012 to August 2013 to determine diet. Based on 294 scats, Moose (Alces americanus) remains made up the highest percentage by volume in scats during fall, winter, and spring. During the summer, Moose remains were found in over 30% of scats (18% by volume), although fruit and berries were more commonly found. No other study has documented such high annual use of Moose. As there was no evidence that the consumed Moose were killed by Coyotes, presumably Coyotes scavenged Moose that had died of natural causes