306 research outputs found
Sospechas y evidencia: revisión de las causas de la extinción local y del declive de los mejillones de agua dulce
Sospechas y evidencia: revisión de las causas de la extinción local y del declive de los mejillones de agua dulce
La conservación de la biodiversidad requiere pruebas fiables de las causas de extinción local. Utilizando los mejillones de agua dulce como ejemplo, llevamos a cabo esta valoración sistemática, la primera que se ha realizado, de la evidencia de peligro para cualquier grupo de organismos. Revisamos artículos que publicaban conclusiones sobre las causas de las extinciones locales, evaluando la calidad de las pruebas según una escala objetiva. Encontramos que únicamente el 48% de los estudios presentaban relaciones plausibles entre la extinción local y sus causas. Los análisis carecían de resolución, dado que más del 75% de los estudios considerados (n = 124) sugerían múltiples causas de extinción local. Los estudios llevados a cabo en grandes áreas, y los que presentaban menos pruebas, son los que abogaban por un mayor número de causas. A pesar de las evidencias, que frecuentemente eran débiles, existía un acuerdo sustancial sobre la identidad de las causas; la más frecuente era la destrucción o alteración del hábitat, pero se postulaban muchas más. A pesar de que la extinción local de los mejillones de agua dulce es indudablemente una realidad, las pruebas podrían ser más consistentes. En estos animales y en muchos otros, la evidencia de las causas de su extinción local a menudo ha sido circunstancial. Presentamos aquí un estudio sistemático que pueden utilizar los ecólogos, para fortalecer las evidencias concernientes a las causas de las extinciones locales. También hemos reflejado la relación entre la fortaleza de la evidencia y las prioridades económicas de las investigaciones.
Palabras clave: Evidencia, Extinción, Extinción local, Agua dulce, Mejillones.Conservation of biodiversity requires reliable evidence of the causes of extirpation. Using freshwater mussels as an example, we performed the first–ever systematic assessment of the evidence for endangerment of any group of organisms. We surveyed articles publishing conclusions about the cause of local extirpation by assessing the quality of evidence on an objective scale. We found that only 48% of studies presented plausible links between extirpation and causes. Analyses lacked resolution since more than 75% of all studies considered (n = 124) suggested multiple causes of extirpation. Studies performed over large areas and those presenting less evidence postulated the most causes. Despite the frequently weak evidence, there was substantial agreement on the identity of causes; the most frequent was habitat destruction or alteration but many others were postulated. Although mussel extirpation is undoubtedly real, the evidence could be stronger. In these animals and others, evidence of the causes of extirpation has often been circumstantial. We present a systematic approach ecologists can use to strengthen the evidence concerning the causes of extirpation. We also reflect on the link between the strength of evidence and research funding priorities.
Key words: Evidence, Extinction, Extirpation, Freshwater, Mussels.La conservación de la biodiversidad requiere pruebas fiables de las causas de extinción local. Utilizando los mejillones de agua dulce como ejemplo, llevamos a cabo esta valoración sistemática, la primera que se ha realizado, de la evidencia de peligro para cualquier grupo de organismos. Revisamos artículos que publicaban conclusiones sobre las causas de las extinciones locales, evaluando la calidad de las pruebas según una escala objetiva. Encontramos que únicamente el 48% de los estudios presentaban relaciones plausibles entre la extinción local y sus causas. Los análisis carecían de resolución, dado que más del 75% de los estudios considerados (n = 124) sugerían múltiples causas de extinción local. Los estudios llevados a cabo en grandes áreas, y los que presentaban menos pruebas, son los que abogaban por un mayor número de causas. A pesar de las evidencias, que frecuentemente eran débiles, existía un acuerdo sustancial sobre la identidad de las causas; la más frecuente era la destrucción o alteración del hábitat, pero se postulaban muchas más. A pesar de que la extinción local de los mejillones de agua dulce es indudablemente una realidad, las pruebas podrían ser más consistentes. En estos animales y en muchos otros, la evidencia de las causas de su extinción local a menudo ha sido circunstancial. Presentamos aquí un estudio sistemático que pueden utilizar los ecólogos, para fortalecer las evidencias concernientes a las causas de las extinciones locales. También hemos reflejado la relación entre la fortaleza de la evidencia y las prioridades económicas de las investigaciones.
Palabras clave: Evidencia, Extinción, Extinción local, Agua dulce, Mejillones
Developing a Healthy Masculinities Program on a University Campus
Amid increased concerns about mental health, sexual violence, and substance use among college students, college campuses are looking toward developing targeted programming to help counteract these concerning trends. This practitioner paper highlights the development and impacts of a program at a Canadian institution, which focuses on healthy masculinity and identity development. Although still in the early stages, the feedback and observations are indicative of the powerful potential of this type of programming to improve healthy masculinity on college campuses
The illegal wildlife trade is a likely source of alien species
The illegal wildlife trade is driving biodiversity declines worldwide, yet its role in transporting alien species with a high likelihood of establishment is seldom considered. We demonstrate the threat posed by the illegal reptile trade in Australia. We modeled the establishment success of alien reptiles in Australia, revealing the importance of both minimum number of release events and the body length of the species. Using our model, we screened 28 alien reptiles illegally traded in Victoria, Australia. Establishment risk varied widely across species, and a whole-pathway analysis revealed that 5 out of the 28 species (17.9%) are likely to become established if released. The global dimension of the illegal wildlife trade calls for a tight transnational collaboration, via multilateral cooperation agreements arranging the share of resources. Complementary to this, we encourage conducting campaigns to raise public awareness about the risk and legal consequences of participating in the wildlife black market.Pablo García-Díaz, Joshua V. Ross, Andrew P. Woolnough, and Phillip Casse
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The implications of an idealised large-scale circulation for mechanical work done by tropical convection
A thermodynamic analysis is presented of an overturning circulation simulated by two cloud resolving models, coupled by a weak temperature gradient
parametrisation. Taken together, they represent two separated regions over
different sea surface temperatures, and the coupling represents an idealised
large-scale circulation such as the Walker circulation. It is demonstrated that a
thermodynamic budget linking net heat input to the generation of mechanical
energy can be partitioned into contributions from the large-scale interaction
between the two regions, as represented by the weak temperature gradient
approximation, and from convective motions in the active warm region and
the suppressed cool region. Model results imply that such thermodynamic
diagnostics for the aggregate system are barely affected by the strength of
the coupling, even its introduction, or by the SST contrast between the regions. This indicates that the weak temperature gradient parametrisation does
not introduce anomalous thermodynamic behaviour. We find that the vertical
kinetic energy associated with the large-scale circulation is more than three
orders of magnitude smaller than the typical vertical kinetic energy in each
region. However, even with very weak coupling circulations, the contrast between the thermodynamic budget terms for the suppressed and active regions
is strong and is relatively insensitive to the degree of the coupling. Additionally, scaling arguments are developed for the relative values of the terms in
the mechanical energy budget
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Diagnosing ocean feedbacks to the MJO: SST-modulated surface fluxes and the moist static energy budget
The composite effect of intraseasonal sea surface temperature (SST) variability on the Madden-Julian Oscillation (MJO) is studied in the context of the column integrated moist static energy (MSE) budget using data from the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-I). SST fluctuations influence the Delta-q and Delta-T parts of the bulk surface latent and sensible heat flux calculations, respectively, each of which influence column MSE. Reynolds decomposition of latent and sensible heat fluxes (LH and SH) reveal that the thermodynamic perturbations modestly offset the equatorial wind-driven perturbations and MSE, but strongly offset the subtropical wind-driven perturbations and MSE. Column moistening east of MJO convection is opposed by wind-driven perturbations and supported by thermodynamic perturbations.
Impacts of intraseasonal SST fluctuations are analyzed by recomputing surface flux component terms using 61-day running-mean SST. Differences between "full SST" and "smoothed SST" projections onto MSE and its tendency yield the "SST effect" on the MJO MSE budget. Particularly in the Indian Ocean, intraseasonal SST fluctuations maintain equatorial MSE anomalies at a rate of 1%-2% per day, and damp subtropical MSE anomalies at a similar rate. Vertical advection exports 10%-20% of MSE per day, implying that the SST modulation of surface fluxes offsets roughly 10% of equatorial MSE export and amplifies by 10% the subtropical MSE export by vertical advection. SST fluctuations support MJO propagation by encouraging on-equator convection and the circulation anomalies that drive MJO propagation, and by contributing up to 10% of MSE tendencies across the Warm Pool
Origins and population genetics of sambar deer (Cervus unicolor) introduced to Australia and New Zealand
Context. Some populations of introduced species cause significant undesirable impacts but can also
act as reservoirs for genetic diversity. Sambar deer (Cervus unicolor) are ‘Vulnerable’ in their native
range and invasive in Australia and New Zealand. Genetic data can be used to determine whether
these introduced populations might serve as genetic reservoirs for declining native populations and
to identify spatial units for management. Aims. We aimed to identify the provenance of sambar deer
in Australia and New Zealand, and to characterise their genetic diversity and population structure.
Methods. We used mitochondrial control region sequences and 18 nuclear microsatellite loci of 24
New Zealand and 63 Australian sambar deer collected across continuous habitat in each location.
We estimated genetic diversity and population differentiation by using pairwise FST, AMOVA, and
STRUCTURE analyses. We compared our data with 27 previously published native and invasive range
sequences to identify phylogenetic relationships. Key results. Sambar deer in Australia and New
Zealand are genetically more similar to those in the west of the native range (South and Central
Highlands of India, and Sri Lanka), than to those in the east (eastern India, and throughout Southeast
Asia). Nuclear genetic diversity was lower than in the native range; only one mitochondrial haplotype
was found in each introduced population. Australian and New Zealand sambar deer were genetically
distinct but there was no population structure within either population. Conclusions. The genetic
differences we identified between these two introduced populations at putatively neutral loci
indicate that there also may be underlying diversity at functional loci. The lack of population genetic
structure that we found within introduced populations suggests that individuals within these popula-
tions do not experience barriers to dispersal across the areas sampled. Implications. Although
genetic diversity is reduced in the introduced range compared with the native range, sambar deer
in Australia and New Zealand harbour unique genetic variants that could be used to strengthen
genetic diversity in populations under threat in the native range. The apparent high levels of gene
flow across the areas we sampled suggest that localised control is unlikely to be effective in Australia
and New Zealand
The Effect of a Brief Salivary α-Amylase Exposure During Chewing on Subsequent in Vitro Starch Digestion Curve Profiles
There is inconsistency between current in vitro digestion methods with regard to accommodation of a (salivary) α-amylase exposure during the oral phase. The effect of a salivary α-amylase pre-exposure on subsequent in vitro starch digestion curve profiles for various foods was investigated. Foods were chewed, expectorated and the boluses left to rest for 0–15 min. During pancreatic digestion, aliquots were taken and hydrolysis curves constructed for comparison against those of the same foods comminuted with a manually-operated chopper, hence spared exposure to saliva. Hydrolysate aliquots taken at T0 (time zero) of the digestion of chewed samples contained higher levels of glucose and dextrins compared with chopped samples. Pancreatin activity immediately overwhelmed differences in sugar released due to salivary amylase activity. Within 10 min no differences were detectable between hydrolysis curves for chewed and chopped foods. Salivary amylase pretreatment does not contribute to the robustness or relative accuracy of in vitro methods
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A climatology of tropical wind shear produced by clustering wind profiles from the Met Office Unified Model (GA7.0)
Toward the goal of linking wind shear with the mesoscale organization of deep convection, a procedure for producing a climatology of tropical wind shear from the output of the Met Office Unified Model climate model is presented. Statistical information from wind profiles from tropical grid columns is used to produce a tractable number (10) of profiles that efficiently span the space of all wind profiles. Physical arguments are used to filter wind profiles that are likely to be associated with organized convection: only grid columns with substantial CAPE and those with shear in the upper quartile are considered. The profiles are rotated so that their wind vectors at 850 hPa are aligned, in order to be able to group like profiles together, and their magnitudes at each level are normalized. To emphasize the effect of lower levels, where the organization effects of shear are thought to be strongest, the profiles above 500 hPa are multiplied by 4. Principal Component Analysis is used to truncate the number of dimensions of the profiles to seven (which explains 90 % of the variance), and the truncated profiles are clustered using a K-means clustering algorithm. The median of each cluster defines a Representative Wind Profile (RWP). Each cluster contains information from thousands of wind profiles with different locations, times, and 850 hPa wind directions.
To summarize the clusters statistically, we interpret the RWPs as pseudo-wind profiles, and display the geographic frequency, seasonal frequency, and histograms of wind direction at 850 hPa for each cluster. Geographic patterns are evident, and certain features of the spatio-temporal distributions are matched to observed distributions of convective organization. The form of the RWPs are also matched to specific wind profiles from case studies of organized convection.
By performing the analysis on climate-model output, we lay the foundations for the development of the representation of shear-induced organization in a Convection Parametrization Scheme (CPS). This would use the same methodology to diagnose where the organization of convection occurs, and modify the CPS in an appropriate manner to represent it. The procedure could also be used as a diagnostic tool for evaluating and comparing climate models
Improved surveillance for early detection of a potential invasive species: the alien Rose-ringed parakeet Psittacula krameri in Australia
Published online: 12 November 2016The Rose-ringed parakeet Psittacula krameri is the most widely introduced parrot in the world, and is an important agricultural pest and competitor with native wildlife. In Australia, it is classified as an ‘extreme threat’, yet captive individuals frequently escape into the wild. The distribution and frequency of incursions are currently unknown, as are the potential impacts of the species in Australia. This lack of critical ecological information greatly limits effective biosecurity surveillance and decision-making efforts. We compiled a unique dataset, which combined passive surveillance sources from government and online resources, for all available information on parakeet detections at-large in Australia. We investigated whether geographic variables successfully predicted parakeet incursions, and used species distribution models to assess the potential distribution and economic impacts on agricultural assets. We recorded 864 incursions for the period 1999–2013; mostly escaped birds reported to missing animal websites. Escapes were reported most frequently within, or around, large cities. Incursions were best predicted by factors related to human presence and activity, such as global human footprint and intensive land uses. We recommend surveillance of high (predicted) establishment areas adjacent to cities where a feral parakeet population could most affect horticultural production. Novel passive surveillance datasets combined with species distribution models can be used to identify the regions where potential invasive species are most likely to establish. Subsequently, active surveillance can be targeted to the areas of highest predicted potential risk. We recommend an integrated approach that includes outreach programs involving local communities, as well as traditional biosecurity surveillance, for detecting new incursions.Miquel Vall-llosera, Andrew P. Woolnough, Dean Anderson, Phillip Casse
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