Abstract We monitored the temperature of seven Paleosuchus palpebrosus nests found on the banks of streams surrounding the Brazilian Pantanal, near the southern limit of the species´ distribution, ...between 2008 and 2013. The mean temperature of the nests between 45 and 68 days incubation, the presumed period of sex determination, varied between 26.1 and 31.5o C. Nest temperatures were 2 to 5°C higher than air temperatures, presumably due to metabolic heat of decay of material within the nests, but air temperature explained 10–50% of the variance in egg-chamber temperatures. The estimated incubation periods for nests from which eggs hatched were 80, 84, 86, 90 and 104 days with a mean of 89 (SD =9.23) days, though these are probably slight overestimates because eggs may have hatched in the period between inspections. For these nests, there was no significant relationship between mean temperature and incubation period (r2 = 0.23, p = 0.411).
Resumo Nós monitoramos a temperatura de sete ninhos de Paleosuchus palpebrosus encontrados nas margens de riachos ao redor do Pantanal, próximo ao limite sul da distribuição da espécie, entre 2008 e 2013. A temperatura média dos ninhos entre 45 e 68 dias de incubação, período presumido de determinação do sexo, variou entre 26,1 e 31,5o C. As temperaturas dos ninhos foram 2 a 5°C mais altas que as temperaturas do ar, presumivelmente devido ao calor metabólico de decomposição do material dentro dos ninhos, mas a temperatura do ar explicou 10-50% da variação na temperatura da câmara de ovo. Os períodos de incubação estimados para os ninhos dos quais os ovos eclodiram foram de 80, 84, 86, 90 e 104 dias com uma média de 89 (DP = 9,23) dias, embora sejam provavelmente pequenas superestimavas porque os ovos podem ter eclodido no período entre as inspeções. Para esses ninhos, não houve relação significativa entre temperatura média e período de incubação (r2 = 0,23, p = 0,411).
Ecological succession in tropical savannas is limited by seasonal fire, which affects habitat quality. Although fire may cause negligible or positive effects on animals occupying savannas, most ...short-term studies (months to a few years) are based on a single temporal sampling snapshot, and long-term studies (decades) are rare. We sampled four lizard species (Rainbow Whiptail, Cnemidophorus lemniscatus (Linnaeus, 1758); Striped Whiptail, Kentropyx striata (Daudin, 1802); Grass Anole, Norops auratus Duméril and Bibron, 1837 = Anolis auratus Daudin, 1802; Amazon Racerunner, Ameiva ameiva (Linnaeus, 1758)) in Amazonian savannas to test the effects of fire and vegetation cover on lizard densities at two temporal scales. In the short term, we use three sampling snapshots to test the effects of fire and vegetation cover on estimated lizard densities over the subsequent 1–5 years. In the long term, we test the effects of fire and changes in vegetation cover over 21 years on current lizard density differences. In the short term, species responses were usually consistent with foraging and thermoregulation modes. However, the results were not consistent among species and years, although the variances in species density explained by year as a random factor were generally low. In the long term, the main effects of fire and vegetation cover show that lizard densities may change spatially, but not necessarily temporarily. Wildfire is a natural resource of savannas and apparently have little impact on resident lizards of that ecosystem.
Surveying and monitoring of elusive animals with naturally low densities and large home ranges, such as many medium‐ and large‐sized mammals, is challenging. Low capture rates can preclude detailed ...analyses. The use of bait has been used as a strategy to increase carnivore capture rates in many camera‐trap surveys. Here, we test the effect of one carnivore bait type (mix of fresh sardine and egg) on the capture rates of carnivores and prey species in a camera‐trap survey in the Central Brazilian Amazon. We also test if the quality of records of naturally marked felids for individual identification is enhanced by the use of bait. We found that the bait had no apparent effect on the carnivore capture rates, but it might have repelled some prey species. The number of suitable photos for individual identification of naturally marked felids was greater at baited stations than at unbaited stations, but this did not result in practical advantages for individual identification. We recommend that the use of carnivore bait should be carefully considered at the planning stage of camera‐trap studies as it can negatively affect recording of prey species.
Baits have been used to increase carnivore capture rates in many camera‐trap surveys as low capture rates can preclude detailed analyses. Here, we test the effect of one carnivore bait type on the capture rates of carnivores and prey species in a camera‐trap survey in the Central Brazilian Amazon. We also test if the quality of records of naturally marked felids for individual identification is enhanced by the use of bait. We found that the bait had no apparent effect on the carnivore capture rates, but it might have repelled some prey species. Moreover, the use of baits did not result in practical advantages for felid individual identification.
. Nyberg ST, Heikkilä K, Fransson EI, Alfredsson L, De Bacquer D, Bjorner JB, Bonenfant S, Borritz M, Burr H, Casini A, Clays E, Dragano N, Erbel R, Geuskens GA, Goldberg M, Hooftman WE, Houtman IL, ...Jöckel K‐H, Kittel F, Knutsson A, Koskenvuo M, Leineweber C, Lunau T, Madsen IEH, Magnusson Hanson LL, Marmot MG, Nielsen ML, Nordin M, Oksanen T, Pentti J, Rugulies R, Siegrist J, Suominen S, Vahtera J, Virtanen M, Westerholm P, Westerlund H, Zins M, Ferrie JE, Theorell T, Steptoe A, Hamer M, Singh‐Manoux A, Batty GD, Kivimäki M, for the IPD‐Work Consortium (Finnish Institute of Occupational Health, Helsinki, Finland; Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Jönköping University, Jönköping, Sweden; Ghent University, Ghent, Belgium; National Research Centre for the Working Environment, Copenhagen, Denmark; Versailles‐Saint Quentin University, Versailles, France; Centre for Research in Epidemiology and Population Health, Villejuif, France; Bispebjerg University Hospital, Copenhagen, Denmark; Centre for Maritime Health and Safety, Esbjerg, Denmark; Université Libre de Bruxelles, Brussels, Belgium; University Duisburg‐Essen, Essen, Germany; West‐German Heart Center Essen, University Duisburg‐Essen, Essen, Germany; TNO, Hoofddorp, the Netherlands; Mid Sweden University, Sundsvall, Sweden; University of Helsinki, Helsinki, Finland; Stockholm University, Stockholm, Sweden; University College London, London, UK; Bispebjerg University Hospital, Copenhagen, Denmark; Umeå University, Umeå, Sweden; Finnish Institute of Occupational Health, Turku, Finland; Harvard School of Public Health, Boston, MA, USA; University of Copenhagen, Copenhagen, Denmark; University of Düsseldorf, Düsseldorf, Germany; University of Turku, Turku; Folkhälsan Research Center, Helsinki; Turku University Hospital, Turku, Finland; Uppsala University, Uppsala; Karolinska Institutet, Stockholm, Sweden; University of Bristol, Bristol; University of Edinburgh, Edinburgh, UK; and University of Helsinki, Helsinki, Finland). Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies. J Intern Med 2012; 272: 65–73.
Background. Evidence of an association between job strain and obesity is inconsistent, mostly limited to small‐scale studies, and does not distinguish between categories of underweight or obesity subclasses.
Objectives. To examine the association between job strain and body mass index (BMI) in a large adult population.
Methods. We performed a pooled cross‐sectional analysis based on individual‐level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow‐up of 4 years was possible for four cohort studies (n = 42 222).
Results. A total of 86 429 participants were of normal weight (BMI 18.5–24.9 kg m−2), 2149 were underweight (BMI < 18.5 kg m−2), 56 572 overweight (BMI 25.0–29.9 kg m−2) and 13 523 class I (BMI 30–34.9 kg m−2) and 3073 classes II/III (BMI ≥ 35 kg m−2) obese. In addition, 27 010 (17%) participants reported job strain. In cross‐sectional analyses, we found increased odds of job strain amongst underweight odds ratio 1.12, 95% confidence interval (CI) 1.00–1.25, obese class I (odds ratio 1.07, 95% CI 1.02–1.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.01–1.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow‐up.
Conclusions. In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a ‘U’‐shaped cross‐sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.
Esophageal adenocarcinoma (EA) is an increasingly common cancer with poor survival. Barrett's esophagus (BE) is the main precursor to EA, and every year 0.12% to 0.5% of BE patients progress to EA. ...BE typically arises on a background of chronic gastroesophageal reflux (GERD), one of the risk factors for EA.
We used genome-wide association data to investigate the genetic architecture underlying GERD, BE, and EA. We applied a method to estimate the variance explained (array heritability, h(2)g) and the genetic correlation (rg) between GERD, BE, and EA by considering all single nucleotide polymorphisms (SNPs) simultaneously. We also estimated the polygenic overlap between GERD, BE, and EA using a prediction approach. All tests were two-sided, except in the case of variance-explained estimation where one-sided tests were used.
We estimated a statistically significant genetic variance explained for BE (h(2)g = 35%; standard error SE = 6%; one-sided P = 1 × 10(-9)) and for EA (h(2)g = 25 %; SE = 5%; one-sided P = 2 × 10(-7)). The genetic correlation between BE and EA was found to be high (rg = 1.0; SE = 0.37). We also estimated a statistically significant polygenic overlap between BE and EA (one-sided P = 1 × 10(-6)), which suggests, together with the high genetic correlation, that shared genes underlie the development of BE and EA. Conversely, no statistically significant results were obtained for GERD.
We have demonstrated that risk to BE and EA is influenced by many germline genetic variants of small effect and that shared polygenic effects contribute to risk of these two diseases.
We used forest inventories, conducted in seventy-two 1-ha permanent plots to assess the variation in tree and palm aboveground live biomass (AGLB), and its relation with soil gradients (texture and ...nutrients) and topography (altitude and slope). Our plots, located at Reserva Florestal Adolpho Ducke, a 10,000
ha reserve in central Amazonia, near the city of Manaus, were systematically spread over 64
km
2. The plots were long (250
m) and narrow (up to 40
m), following elevational contours. Chemical and physical soil analyses were undertaken using topsoil samples, collected in each plot. The plots covered a soil textural gradient ranging from 8% to 98% percent of sand, slopes varying from 0.5° to 27°, and the maximum difference of altitude among plots was 70
m, ranging from 39 to 109
m
a.s.l. The mean total AGLB (palm
+
trees) for stems over 1
cm diameter breast height (dbh
=
1.3
m), was 327.8
Mg/ha (ranging from 210.9 to 426.3) and was similar to other studies in the region. We found a two-fold variation in total AGLB estimates among plots, with soil or topography explaining around 20% of this variation. AGLB was positively related to either a soil textural gradient (represented by the percentage of clay) or altitude, but was insensitive to slope. Although slope had no detectable effect on the mean variation of AGLB per plot, it explained 14% of the AGLB in understory and emergent trees. On slopes, AGLB is concentrated mostly in tree classes of small size (1
≤
dbh
<
10
cm), whereas in flat areas, most of the biomass is concentrated in a few big trees. When considering palms and trees separately, we found that tree biomass tended to increase in clay-rich soils (mostly located in high areas), whereas palm biomass was higher in sandy soils (low slopes and bottomlands). This study shows that forests in central Amazonia grow in a heterogeneous environment in relation to soil and topography, and this heterogeneity seems to be in part responsible for differences in structure and AGLB accumulation. In the forest around Manaus, topography can be used to predict aboveground live biomass as an alternative to soil variables, with similar predictive power. Topographic variables can be easily assessed using satellite imagery and could improve current estimates of carbon stocks over large areas in the Amazon.
Over the past century, human activities and their side effects have significantly threatened both ecosystems and resident species. Nevertheless, the genetic patterns of large felids that depend ...heavily on large and well-conserved continuous habitat remain poorly studied. Using the largest-ever contemporary genetic survey of wild jaguars (Panthera onca), we evaluated their genetic diversity and population structure in natural (Brazilian Amazon) and highly modified habitats (e.g. Cerrado, Caatinga) including those close to the northern (Yucatan, Mexico) and southern (Pantanal) edge of the species’ distribution range. Data from our set of microsatellites revealed a pronounced genetic structure, with four genetically differentiated geographic areas. Geographic distance was not the only factor influencing genetic differentiation through the jaguar range. Instead, we found evidence of the effects of habitat deterioration on genetic patterns: while the levels of genetic diversity in the Amazon forest, the largest continuum habitat for the species, are high and consistent with panmixia across large distances, genetic diversity near the edge of the species distribution has been reduced through population contractions. Mexican jaguar populations were highly differentiated from those in Brazil and genetically depauperated. An isolated population from the Caatinga showed the genetic effects of a recent demographic decline (within the last 20–30 years), which may reflect recent habitat degradation in the region. Our results demonstrate that the jaguar is highly sensitive to habitat fragmentation especially in human-dominated landscapes, and that in Brazil, the existing but limited genetic connectivity in the central protected areas should be maintained. These conclusions have important implications for the management of wide-ranging species with high dispersal and low population density. The restoration of ecological connectivity between populations over relatively large scales should be one of the main priorities for species conservation.
Post-hatching parental care is common in crocodilians, but the little information available for Cuvier's dwarf caiman (Paleosuchus palpebrosus) indicates that they show little post-hatching parental ...care. During surveys undertaken between 2005 and 2011, we counted and captured groups of hatchlings and observed the presence or absence of attending adults in streams around the Pantanal, along the Guaporé-Madeira River and flooded forest in central Amazonia, Brazil. We found 37 groups of hatchlings, of which 29 were accompanied by adults. We captured 13 of these adults and all were females. The groups of hatchlings remained with adults for up to 21 months. We monitored females and hatchlings in streams around the Pantanal using captures and with radiotelemetry and showed that females and hatchlings frequently remained together in burrows, especially during the dry season.
Faeces similarity among sympatric felid species has generally hampered their use in distributional, demographic and dietary studies. Here, we present a new and simple approach based on a set of ...species‐specific primers, for the unambiguous identification of faeces from sympatric neotropical felids (i.e. puma, jaguar, jaguarundi and ocelot/ margay). This method, referred to as rapid classificatory protocol‐PCR (RCP‐PCR), consists of a single‐tube multiplex PCR yielding species‐specific banding patterns on agarose gel. The method was optimized with samples of known origin (14 blood and 15 fresh faeces) and validated in faecal samples of unknown origin (n = 138), for some of which (n = 40) we also obtained species identification based on mtDNA sequencing. This approach proved reliable and provides high identification success rates from faeces. Its simplicity and cost effectiveness should facilitate its application for routine surveys of presence and abundance of these species.
Nests of Schneider's dwarf caiman, Paleosuchus trigonatus, were located in the forests around three streams that drain into the Xingu River, Brazilian Amazonia, in October 2014. Camera traps were ...installed at the edge of four nests to document predators and female parental care. At two nests, females unsuccessfully defended their nests against one or more giant armadillos, Priodontes maximus, and nine-banded armadillos, Dasypus novemcinctus. Both armadillo species responded to the attack by fleeing and returning on the opposite side of the nest by going around the tree under which the nest was located. Giant armadillos have never before been recorded consuming caiman eggs and their diet has been described as consisting mostly of ants and termites. Another species of armadillo, Cabassous unicinctus, was also registered digging into a nest and probably consuming eggs, though it is generally considered to be primarily insectivorous. A tayra (Eira barbara), lizard (Tupinambis teguixin) and coati (Nasua nasua) were also registered taking eggs from nests during the day, but we obtained no registers of nest defence by caimans during the day. The three nests were attacked after 60 days of incubation, when the eggs were well developed.
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