Modelling power‐line collision risk for the Blue Crane Anthropoides paradiseus in South Africa

The Overberg wheatbelt population of Blue Cranes Anthropoides paradiseus in the Western Cape of South Africa is approximately half the global population of this vulnerable species. Blue Cranes are highly susceptible to collisions with overhead power lines, and a spatial model was developed to identify high‐risk lines in the Overberg for proactive mitigation. To ground‐truth this model, we surveyed 199 km of power lines. Although Blue Cranes were the most commonly killed birds found (54% of all carcasses), the model was unable to predict lines with high collision risk for Blue Cranes. Further Geographic Information System (GIS) modelling was undertaken to test a wider range of landscape and power‐line variables, but only the presence or absence of cultivated land could usefully identify lines posing a collision risk. Modelling was limited by a lack of detailed spatial habitat data and recent information on Crane numbers and distributions. We used recent carcass counts to estimate a Blue Crane collision rate, corrected for sample biases, of 0.31/km power line per year (95% CI 0.13–0.59/km/year), which means that approximately 12% (5–23%) of the total Blue Crane population within the Overberg study area is killed annually in power‐line collisions. This represents a possibly unsustainable source of mortality. There is urgent need for further research into risk factors and for mitigation measures to be more widely implemented.     

Troop fission in femaleLemur catta at berenty reserve,Madagascar

A- Troop of Lemur cattaat Berenty Reserve, Madagascar, divided in July- August 1992. We observed the daughter troops— Al and A2— between Aug. 15 and Nov. 15. The subordinate female subgroup of A- Troop (A2) had been harassed for at least 3 years previously. After fission, it suffered high conflict and energy demands, wounding, and socially induced infant mortality. Costs of fission may be a pressure for remaining in large troops. In September, A2 ranged widely, was chased by all neighbor troops, but then it challenged the previously dominant subgroup, Al, and by late October occupied a portion of the previous A- Troop range in which it was consistently successful in confrontations. A2's acquisition of range may relate to its high affiliation and low conflict between females of the subgroup. Unlike previously reported fission in L. cattathere was no male involvement in defense, and the females that lost infants became more aggressive. This may be interpreted as female competition for resource control.     

Patterns of emergence,import of egg energy and energy export via emerging dragonfly populations in a tropical pond

The most abundant dragonflies Brachythemis contaminata, Orthetrum sabina, Diplacodes trivialis, Pantala flavescens and Trithemis festiva in the tropical pond Idumban emerged from November to April during the years 1973,1974 and 1975. The date of initiation of emergence of all the species was synchronized and tied to the events following the north west monsoon in November. During the seasons '73–74 and '74–75, as many as 10,693 and 7,910 adults emerged; females outnumbered the males in all the 5 species; male populations of B. contaminata, O. sabina, D. trivialis, P. flavescens and T. festiva represented 47, 48, 46, 49 and 44% during the '73–74 season, 48, 48, 46, 46 and 49% during the '74–75 season, respectively. The adult dragonflies equivalent to 2,442 Kcal emerged from the Pond during the season '73–74. Of this, B. contaminata contributed 30%, D. trivialis 7%, O. sabina 12%, P. flavescens 23% and T. festiva 28%. For the season '74–75, the dragonflies equivalent to 1,602 Kcal emerged from the Pond and the contribution was in the following order: B. contaminata: 31%, O. sabina: 8%, D. trivialis: 13%, P. flavescens: 27% and T. festiva: 21%. Import of energy due to inoculation of B. contaminata eggs into the Pond Idumban was 73 Kcal/ year and the output from the Pond via emerging B. contaminata population alone amounted to 620 Kcal/ year; the net energy loss from the Pond was 548 Kcal/ year. During either season, as much as 99.7% of B. contaminata eggs failed to attain adulthood due to infertility (5.8%), unhatchability (12%) and predation during the egg and nymphal stages (82.5%). During the study, the GPP of the Pond was 26,073 Kcal/m²/ year, and output of energy through emergence of 5 dragonfly species amounted to 0.0045 Kcal/m²/year, i.e. 0.00002% of the GPP is lost through the emerging carnivorous odonates; comparable values available for the emerging detritivorous chironomids, herbivorous dipterans and mayflies fall between 1.0 and 0.1%.     

Structure and projected decline of a Karoo dwarf tortoise population

Inconspicuous, secretive, or sparsely distributed species receive relatively little research attention, potentially leading to uncertainty about their status and lack of efforts to conserve them. Karoo dwarf tortoises (Chersobius boulengeri) are endemic to South Africa, spend most of the time in retreats at remote arid locations, and are seldom seen. We conducted a 3-year (2018–2020) mark-recapture study to investigate the size and structure of the only Karoo dwarf tortoise population currently known to exist. The population in the 16-ha core of our study site consisted primarily of adult males and females, at a density of 3.3 individuals/ha. Many individuals had severely worn shells and appeared old. Small individuals (straight carapace length <65 mm) represented just 8% of the population and were mostly recent hatchlings. Overall, tortoises had high estimated survival rates (0.77–0.95; lower 95% confidence limit for the smallest tortoises was 0.16), despite a 15-month drought. The lack of small individuals may reflect low levels of recruitment and population decline. Predation by corvids was an obvious threat to all size classes. We estimated that the local population across the 250-ha study area was 800–900 males and females, and recommend precautionary conservation measures focused on reducing human-subsidized avian predation.     

N-Exponential Fertilization Could Affect the Growth and Nitrogen Accumulation of <i>Metasequoia glyptostroboides</i> Seedling in a Greenhouse Environment

Metasequoia glyptostroboides (M. glyptostroboides) is a unique plant species related to relic flora in China. It plays a positive role in afforestation and its long-term protection with high paleoclimate research value. However, due to the nutrients-supply deficiency, it is a big challenge to cultivate the high-quality seedlings of M. glyptostroboides. In this study, a pot experiment in a greenhouse environment was carried out to identify the effect of N-exponential fertilization on the growth and nutrient distribution of M. glyptostroboides seedling. The M. glyptostroboides rooted seedlings with 12-month growth were chosen. Different N fertilizer levels with conventional fertilization (CF: 5.0 g seedling⁻¹), exponential fertilization including EF1, EF2, EF3 and EF4 were determined. The relevant growth indexes were measured after 210-day growth. The results indicated that non-significant differences in seedlings’ height and ground diameter were found among the above treatments (P > 0.05); At the same time, N-exponential fertilization promoted the M. glyptostroboides’s biomass in different organs (P < 0.05), with the maximum total biomass under EF3 treatment. The N accumulation in root and stem of the N-exponential fertilization treatments were increased in to some extent (P < 0.05). The maximum N accumulation was also found under EF3 treatment. Therefore, steady-state nutrition and superior growth performance of M. glyptostroboides could be obtained by N-exponential fertilization of 5.0 g cutting⁻¹.     

Effect of dietary protein and energy intake on embryonic survival and gene expression in the uterine endometrium of early pregnant gilts

Porcine embryonic loss during early gestation is a serious problem in swine production. Improving embryonic survival can be achieved by maternal manipulation. Protein and energy are two major components of the diet, which play decisive roles in embryonic survival. This study was performed to evaluate the effects of enhancing maternal protein or energy intake on embryonic survival during early gestation in gilts and to explore the underlying mechanism. From day (d) 0 to 30 of gestation, 40 gilts (Landrace × York) were randomly allocated to 5 diets according to daily intake of low (L, National Research Council (NRC) recommendation for gestation gilts), medium (M, 20% higher than NRC) or high (H, 40% higher than NRC) CP or metabolisable energy (ME) (L_CPL_ME, M_CPL_ME, H_CPL_ME, L_CPH_ME, H_CPH_ME). Gilts were sacrificed on d 30 of gestation, and number of foetuses and corpora lutea, embryonic survival rate, uterine weight, and total volume of allantoic fluid were recorded or calculated. Gene expression was determined by Quantitative Real-time PCR (qPCR), western blot or immunohistochemistry. Results showed that increasing protein or ME intake significantly increased embryonic survival rate. Compared with diet L_CPL_ME, plasma progesterone (P4) concentration in diet L_CPH_ME increased at d 14 and d 30 of gestation. Progesterone receptor (PGR) was found not to be expressed in the epithelia but was strongly expressed in the stroma of the endometrium. Increasing protein or ME intake did not alter PGR expression in the endometrium. There was also no change in the amount of P4, hepatocyte growth factor, and fibroblast growth factor-7 in the endometrium. The mRNA abundance of cationic amino acid transporter 1 in the endometrium in diet L_CPH_ME and H_CPH_ME was significantly lower than in diet L_CPL_ME. Diet H_CPL_ME showed a tendency to increase neutral amino acid transporter 1 mRNA expression in the endometrium compared to diet L_CPL_ME (P = 0.087). In conclusion, increasing maternal protein or ME intake had a positive effect on the embryonic survival. Increased protein intake by 20 or 40% did not alter plasma P4 level, but increasing ME intake by 40% improved plasma P4 concentration at d 14 and 30 of gestation. Increasing maternal protein or ME intake did not induce PGR expression in the endometrium. Maternal protein and energy intake likely mediate transportation of cationic and neutral amino acids from mother to foetus to affect embryonic survival and development.