Note on improvement precision of recursive function simulation in floating point standard

An improvement on precision of recursive function simulation in IEEE floating point standard is presented. It is shown that the average of rounding towards negative infinite and rounding towards positive infinite yields a better result than the usual standard rounding to the nearest in the simulation of recursive functions. In general, the method improves one digit of precision and it has also been useful to avoid divergence from a correct stationary regime in the logistic map. Numerical studies are presented to illustrate the method.Comment: DINCON 2017 - Conferencia Brasileira de Dinamica, Controle e Aplicacoes - Sao Jose do Rio Preto - Brazil. 8 page

Highly feminised sex ratio estimations for the world’s third largest nesting aggregation of loggerhead sea turtles

Despite being a fundamental life-history character, there is a paucity of populationwide, data-driven studies of primary sex ratios for any marine turtle species. The Republic of Cape Verde hosts the third-largest nesting population of loggerhead turtles Caretta caretta in the world (hosting up to 15% of global nesting by the species). Weighting for the spatial distribution of nests, we estimate that 84% of female hatchlings are currently likely produced across the population, with 85% of nests laid on Boa Vista, where incubation temperatures are coolest. In future climate change scenarios (by 2100), irrespective of beach, island or sand colour, sex ratios reach over 99% female, and 3 islands (Fogo, Sao Nicolau, Santiago) would cease to produce males, with &gt;90% of nests incubating at lethally high temperatures. Given that most of the population cannot move to nest on cooler islands, we highlight that temporal refugia are amongst the primary means available to this population to adapt. Under a low-emissions scenario, without phenological adaptation, there would only be an estimated 0.14% males produced across the whole population, while under mid- and high-emissions scenarios, male production may cease on most islands.</p

Highly feminised sex ratio estimations for the world’s third largest nesting aggregation of loggerhead sea turtles

Despite being a fundamental life-history character, there is a paucity of populationwide, data-driven studies of primary sex ratios for any marine turtle species. The Republic of Cape Verde hosts the third-largest nesting population of loggerhead turtles Caretta caretta in the world (hosting up to 15% of global nesting by the species). Weighting for the spatial distribution of nests, we estimate that 84% of female hatchlings are currently likely produced across the population, with 85% of nests laid on Boa Vista, where incubation temperatures are coolest. In future climate change scenarios (by 2100), irrespective of beach, island or sand colour, sex ratios reach over 99% female, and 3 islands (Fogo, Sao Nicolau, Santiago) would cease to produce males, with &gt;90% of nests incubating at lethally high temperatures. Given that most of the population cannot move to nest on cooler islands, we highlight that temporal refugia are amongst the primary means available to this population to adapt. Under a low-emissions scenario, without phenological adaptation, there would only be an estimated 0.14% males produced across the whole population, while under mid- and high-emissions scenarios, male production may cease on most islands.</p

High variability in nest site selection in a loggerhead turtle rookery, in Boa Vista Island, Cabo Verde

Among sea turtles, nest site selection is a crucial factor for hatching success and population viability. The relocation of otherwise doomed clutches to safe hatcheries has been widely promoted as a conservation strategy, although this may promote artificial selection of poorly adapted genotypes. In this study, we used multiyear spatial nesting data of individual loggerhead turtles (Caretta caretta) from one of the largest Atlantic rookeries, in Cabo Verde, across six consecutive nesting seasons (2013–2018), to identify spatial nesting patterns, assess how individual nest site selection is influenced by female size and age, and estimate the impacts on the reproductive output. Although females nested across the entire beach width, they preferentially nested in the middle of the beach, avoiding to nest both close to the tideline and close to the vegetation line. Hatching success decreased towards the waterline, while the risk of nest inundation or predation was high, regardless of nest location. In general, females showed high variability in nest site selection, except larger females (> 93 cm curved carapace length) that showed higher repeatability (r = 0.50, SE = 0.14, 95% CI: 0.16–0.72) in distances to the vegetation. We therefore suggest that the relocation of doomed clutches should be considered for this endangered rookery, as clutch relocation should not substantially distort the gene pool, assuming nest choice is a heritable trait. In addition, we recommend the preservation of beach vegetation, particularly in areas with human developmet.info:eu-repo/semantics/publishedVersio

Risk assessment of wildlife-watching tourism in an important endangered loggerhead turtle rookery

T: Wildlife-watching tourism is a non-exploitative activity that can contribute to sustainable economic development of coastal communities. However, it is important to assess the potential impact and implement best practices to mitigate any negative effects of such tourism. We studied this issue on Boa Vista (Cabo Verde), which supports around 60% of nesting activity of one of the most endangered loggerhead turtle rookeries globally. Between 2013 and 2016, authorized turtle watching involved 4942 tourists, generating a mean annual direct income of >USD 289 000 and the direct creation of >250 jobs. On João Barrosa beach, which supports around 20% of nests and 48% of turtle-watching activity on the island, we tested the influence of turtle watching on nesting behavior, reproduction and nest-site fidelity. Nesting females observed by tourists spent significantly less time on nest-camouflaging behavior, although all other phases of nesting were unaffected. There were no statistically significant differences between the re-nesting frequency of females watched (n = 187) and non-watched (n = 972) by tourists. We found no evidence that the current turtle-watching intensity has an effect on turtle reproduction. Turtle poaching remains a severe threat on beaches with no turtle watching, although it has strongly decreased on beaches with tourist visits. We suggest tour guides follow best practice guidelines to minimize disturbance, specifically retreating from the immediate vicinity of a female during nest camouflaging to mitigate the observed impact.Peer reviewe

Effect of body size on the long-term reproductive output of eastern Atlantic loggerhead turtles Caretta caretta

We assessed the relationship between body size and several important life history parameters to understand the demographic significance of interpopulation variability in the body size of loggerhead turtles Caretta caretta nesting on Boa Vista Island (Cabo Verde). The adult growth rate (0.34 +/- 0.60 cm yr-1), annual mortality rate (0.13, 95% CI: 0.12-0.15) and remigration interval (3.1 +/- 1.2 yr) were independent of curved carapace length (minimum curved carapace length [CCLmin]). Conversely, the body condition index decreased significantly with female CCLmin. The clutch size, mean egg mass, mean hatchling straight carapace length and mean hatchling mass increased significantly with female CCLmin. However, there was no relationship between female size and hatching success. Randomization and bootstrapping were used to incorporate variability when calculating the average individual fecundity over 20 yr, a period that accumulated, on average, 94% of the adult mortality. The overall fecundity during this period increased with carapace length at first maturity (71 cm CCLmin: 815 eggs, 95% CI: 653-863; 80 cm CCLmin: 906 eggs, 95% CI: 822-959; 90 cm CCLmin: 1089 eggs, 95% CI: 926-1415). However, only 8% of the adult females nesting on Boa Vista Island are larger than 90 cm CCLmin, and they produce less than 12% of the total annual egg production. The scarcity of large females might result from a shortage of high-quality foraging grounds where females may reach first sexual maturity at a large carapace length and from the combined effect of a small carapace length at first sexual maturity, low adult somatic growth and high adult mortality.info:eu-repo/semantics/publishedVersio