Consideration of genetic variation and evolutionary history in future conservation of Indian one-horned rhinoceros (Rhinoceros unicornis)

The extant members of the Eurasian rhino species have experienced severe population and range declines through a combination of natural and anthropogenic factors since the Pleistocene. The one-horned rhino is the only Asian species recovered from such strong population decline but most of their fragmented populations in India and Nepal are reaching carrying capacity. Implementation of any future reintroduction-based conservation efforts would greatly benefit from currently unavailable detailed genetic assessments and the evolutionary history of these populations. We sequenced wild one-horned rhino mitogenomes from all the extant populations (n=16 individuals) for the first time, identified the polymorphic sites and assessed genetic variation (2531bp mtDNA, n=111 individuals) across India. Results showed 30 unique rhino haplotypes distributed as three distinct genetic clades (Fst value 0.68-1) corresponding to the states of Assam (n=28 haplotypes), West Bengal and Uttar Pradesh (both monomorphic). Phylogenetic analyses suggest earlier coalescence of Assam (~0.5 Mya) followed by parallel divergence of West Bengal and Uttar Pradesh/Nepal (~0.06-0.05Mya), supported by the paleobiogeographic history of the Indian subcontinent. Combined together, we propose recognising three Evolutionary Significant Units (ESUs) of the Indian rhino. As recent assessments suggest further genetic isolations of the Indian rhinos at local scales, future management efforts should focus on identifying genetically variable founder animals and consider periodic supplementation events while planning future rhino reintroduction programs in India. Such well-informed, multidisciplinary approach is the only way to ensure evolutionary, ecological and demographic stability of the species across its range.

Pollinator community response to planted pollinator habitat in agroecosystems over time

Pollinators are important both ecologically and economically, with the majority of flowering plants and many of the world’s crop species relying on animal pollination—the majority of which is provided by bees. However, documented pollinator population decline threatens ecosystem functioning and human well-being. As such, conservation methods such as augmented pollinator habitat are becoming popular tools to combat pollinator losses. In our study, we evaluate an initiative to plant pollinator habitat at all North Carolina agricultural research stations to ensure that these efforts result in improved bee communities. From 2016 to 2018, we found significant increases in bee abundance and community diversity. These increases depended on the quality of habitat, with plots with higher cover and more plant diversity supporting larger, more diverse bee communities. Although the habitat positively supported bee communities, we found that overall habitat quality degraded over the course of our study. This points to the need of regular upkeep and maintenance of pollinator habitat in order for it to appropriately support bee communities. Future long-term studies on pollinators will be important as natural fluctuations in bee populations may limit findings and many knowledge gaps on native bees still persist.

Light Competition Contributes to the Death of Masson Pines of Coniferous-Broadleaf Mixed Forests in Subtropical China

In the process of subtropical forest succession, it has long been recognized that population decline of Masson pines in coniferous-broadleaf mixed forest is caused by shading from broadleaf trees. However, little is known about the mechanism underlying the interaction between them. Here, we first chose two sets of Masson pine plots approximately aged 60 years in subtropical mountainous areas in eastern China (i.e., pure coniferous forest vs. coniferous-broadleaf mixed forest). Then, we measured and compared tree height, diameter at breast height, first branch height (FBH), live crown ratio (LCR) of Masson pines between the two sets of plots, and also determined the difference in growth performance of Masson pines relative to their neighboring broadleaf trees in the mixed forest stand. Compared with plots in pine forests, Masson pines in mixed plots had lower tree height and crown breadth, higher FBH, lower LCR, and leaf area. Furthermore, the difference of mean FBH between reference trees (Masson pines) and their neighboring trees (i.e., broadleaf trees) in mixed forest plots was greater than that in pine forest plots, and the ratio of LCR between Masson pines and their neighbors (0.46) in mixed forest was significantly smaller than in pine forest (1.05), indicating that those broadleaf trees around Masson pines probably affected their growth. The mean distance between Masson pines and neighboring trees (1.59 m) in mixed forest plots was significantly shorter than in pine forest plots (2.77 m) (p < 0.01), suggesting that strong competition may occur between reference trees and their neighbors. There was a significant difference in the ratio of crown volume between reference tree Masson pine and its neighboring trees in mixed forests (p < 0.01), indicating that the ratio of biomass synthesis to consumption of pines was much lower than their nearby broadleaf trees in mixed forest. Our results have demonstrated for the first time that Masson pines’ population decline is affected by shade-tolerant broadleaf late-successional species, which can be primarily attributed to the distinctive light transmittance of dominant species nearby (pure pine vs. mixed forest). This study provides a new perspective for future studies on the mechanism of forest succession.

Detecting Population Regulation of Winter Flounder from Noisy Data

Year-class size of marine fish is thought to be determined during the first year of life, with density-dependent mortality during the larval or juvenile stages. However, investigations of such dynamics are often limited by data availability. To test this paradigm for winter flounder (Pseudopleuronectes americanus) in Narragansett Bay, Rhode Island, the abundances of 29 year classes moving through seven life stages were analyzed with a novel extension of key-factor analysis. Evidence of density dependence was identified between the egg and July young-of-the-year stages and high process-error variance was detected throughout the life cycle, suggesting year-class size is not fully determined until age-2. However, the first summer appeared to be a critical life stage for winter flounder, during which high temperatures, hypoxia, and predator abundance contributed to increased mortality rates behind a long-term population decline. Due to its general data requirements, the key-factor analysis method developed here may be applied to other marine populations to identify the impacts of external stressors at particular life stages and the degree to which they are compensated by density-dependent processes.

US demographic change will have broad economic effects

Significance This has implications for the size of the workforce and the living standards that the US economy is capable of supporting. It will also have broader consequences for the US economy over the next 30 years. Impacts Lower workforce participation rates will lower average living standards, relative to what they would have otherwise been, by 10% by 2050. Medicare and social security spending will rise by 4% of GDP over the next 30 years; higher taxes or spending cuts elsewhere will be needed. Immigration is projected to be just sufficient to offset natural population decline by 2050, cushioning the working-age population drop. Estimating the extent to which immigration and automation could help to fill worker shortages over the longer term is difficult.

Occurrence and relevance of Mycoplasma spp. in free-ranging pheasants from northwestern Germany

Since 2008/2009, the population of free-ranging ring-necked pheasants was recorded to decrease all over Germany. Various Mycoplasma (M.) spp. are causing severe respiratory signs in captive game bird species. Furthermore, M. gallisepticum is responsible for massive die-offs in consequence to severe conjunctivitis in house finches in the USA. Therefore, the prevalence of mycoplasmas in free-ranging pheasants was investigated and a potential impact on the population decline of pheasants discussed. Within this study, 150 free-ranging pheasants were sampled via tracheal swabs and tissue samples of the trachea and the periorbital skin, as the latter displayed inflammatory alterations in previous studies. In total, 177 samples were investigated for the presence of mycoplasmas using cultural and molecular biological methods. In 76 birds, necropsy was performed additionally. In total, 73.7% (51/76) of the examined pheasants had periorbital skin alterations. Furthermore, 64.4% (114/177) of the samples tested positive for mycoplasmas via PCR. Overall, 102/177 samples (57.6%, 78/105 tracheal swabs, 19/51 skin tissue, 5/21 trachea tissue) tested positive for mycoplasmas via culture. Mycoplasma gallinaceum (n = 50), M. pullorum (n = 45), M. glycophilum (n = 43), M. iners (n = 11), and M. gallinarum (n = 5) were frequently isolated. In 45 cases (45.9%), multiple Mycoplasma spp. were isolated from one sample. All examined samples tested negative for M. gallisepticum. Of 51 skin samples investigated for mycoplasmas, 24 (47.1%) showed inflammatory skin alterations in histology, and 58.3% (14/24) of these samples tested positive for Mycoplasma spp. additionally. Overall, there was a significant correlation between inflammatory altered skin samples and the detection of mycoplasmas in periorbital skin samples. Based on the present results, the isolated Mycoplasma spp. may play a role as facultative agents for the observed inflammatory skin alterations. However, additional investigation is needed to confirm this presumption.

Genetic Variability Trend of Lusitano Horse Breed Reared in Italy

The Lusitano Horse (LH) originates from Portugal, but is reared worldwide. Since 1994, the University of Milan has routinely tested the LHs bred in Italy for parentage control. This study aims to assess the genetic variability of the LH reared in Italy using 16 microsatellites markers. Moreover, the genetic variability changes over the years in the total population (n.384) and in unrelated horses (n.47) were evaluated. Horses were grouped according to their date of birth (1975–1990, 1991–2000, 2001–2010, 2010–2019). Standard genetic diversity parameters, including observed (Ho) and expected (He) heterozygosity, Hardy-Weinberg equilibrium (HWE; P-Val), allelic richness, and inbreeding coefficient (Fis) were estimated. In the whole period, the total population showed Ho as high as 0.69, low Fis (0.057), and imbalance for HWE. When considering the unrelated horses, Ho was seen to increase over time (from 0.594 in 1975–1990 to 0.68 in 2010–2019) and frequencies were in HWE, again having low and decreasing values of Fis (from 0.208 in 1975–1990 to 0.019 in 2010–2019). Bottleneck analysis excluded a recent population decline. Principal Coordinate Analysis at the individual level defined two clusters, the major cluster including all the most recent horses. An increasing number of dams (156% more from 2001–2010 to 2011–2019) supports the good variability recorded in the population so far. However, the high number of foals (77.2%) sired by only four stallions in recent years suggests caution in the choice of the sires for the future.