Montane forest birds in winter: do they regularly move to lower altitudes? Observations from the Eastern Cape,South Africa

Seasonal altitudinal migration to lower altitudes including the coast has been ascribed to a number of forest birds, of which 14 species occur at Fort Fordyce Reserve in the Eastern Cape, South Africa. Based on our observations and ringing at this site (2007–2017), as well as concurrent data from the South African Bird Atlas Project (SABAP2), we suggest that in this region only three species, the African Dusky Flycatcher Muscicapa adusta, White-starred Robin Pogonocichla stellata and Barratt's Warbler Bradypterus barratti, are regular altitudinal migrants. For two other species, the Grey Cuckooshrike Coracina caesia and Yellow-throated Woodland Warbler Phylloscopus ruficapilla, local movements apparently occur, but these may take place within the coastal zone rather than between the coast and inland forests.     

Faunal diversity and endemicity of the Cape Peninsula, South Africa — a first assessment

A total of 322 records were available from the literature on faunal taxa endemic to the Cape Peninsula, South Africa. Excluding possible pseudoendemics, dubious records and many invertebrate groups for which little or no information exists, these records represent 112 species (1 vertebrate and the rest invertebrates) in 47 families. This number excludes many other potential endemics having distributions that extend just off the Peninsula. When mapped according to a 590 1 km×1 km grid, these endemics were clustered in several, largely montane nodes and palaeogenic (palaeoclimatically stable) zones typically located in upper reach forest streams, riverine forest and caves (the latter supported 14 endemics). Endemics were over-represented on steep slopes. For many taxa, a very high percentage of the Peninsula representatives were endemics. There were more plant than animal endemics per 1 km² cell, although in total there were more animal than plant endemics. A significant correlation existed between the distribution of plant and animal endemics on the Peninsula, and especially on Table Mountain. The relationship, however, appears not to be causal, and is possibly related to parallel responses to historical isolation and topography. As the endemic fauna is mostly relictual, conservation of umbrella plant communities and the sandstone caves is essential. This may avert further extinction (some invertebrate endemics are likely to be extinct at this stage). Others have suffered declines in population numbers through development, invasion of alien vegetation, and possibly through predetion by the introduced Argentine ant.     

Does the removal of snowpack and the consequent changes in soil frost affect the physiology of Norway spruce needles?

Climate change may cause a decrease in snow cover in northern latitudes. This, on the other hand, may result in more severe soil frost even in areas where it is not common at present, and may lead to increased stress on the tree canopy. We studied the effects of snow removal and consequent changes in soil frost and water content on the physiology of Norway spruce (Picea abies [L.] Karst.) needles and implications on root biomass. The study was conducted at a 47-year-old Norway spruce stand in eastern Finland during the two winters of 2005/06 and 2006/07. The treatments in three replicates were: (i) natural snow accumulation and melting (CTRL), (ii) artificial snow removal during the winter (OPEN), and (iii) the same as OPEN, but the ground was insulated in early spring to delay soil thawing (FROST). In spite of the deeper soil frost in the OPEN than in the CTRL treatment, soil warming in spring occurred at the same time, whereas soil warming in the FROST was delayed by 2 and 1.5 months in 2006 and 2007, respectively. The soil water content was affected by snow manipulations, being at a lower level in the OPEN and FROST than CTRL in spring and early summer. The physiological measurements of the needles (e.g. starch, carbon and nitrogen content and apoplastic electrical resistance) showed differences between soil frost treatments. The differences were mostly seen between the CTRL and FROST, but also in the case of the starch content in early spring 2007 between the CTRL and OPEN. The needle responses in the FROST were more evident after the colder winter of 2006. The physiological changes seemed to be related to the soil temperature and water content in the early growing season rather than to the wintertime soil temperature. No difference was found in the fine root (diameter < 2 mm) biomass between the treatments assessed in 2007. In the future, conditions similar to the OPEN treatment may be more common than at present in areas experiencing a thick snow cover. The present experiment took place over the course of two years. It is possible that whenever thin snow cover occurs yearly, the reduced starch content during the early spring may be reflected in the tree growth itself as a result of reduced energy reserves.     

Does background nitrogen deposition affect the response of boreal vegetation to fertilization?

Forest floor vegetation is an important component of forest biodiversity, and numerous studies have shown that N input alters the vegetation. In some cases, however, the effects of experimental N addition have been small or absent. Two alternative hypotheses have been suggested: (a) competition from the tree layer confounds the response to N, or (b) N response in areas with high background deposition is limited by N saturation. Neither of these hypotheses has so far been explicitly tested. Here, we compile data on forest floor vegetation from N addition experiments, in which the forest had been clear-cut, along an N deposition gradient ranging from 4 to 16 kg ha^?1 year^?1 in Sweden. We analyzed the effects of N addition and its interaction with N deposition on common species and thereby tested the second hypothesis in an environment without the confounding effects of the tree layer. The results show that the effects of the experimental N addition are significantly influenced by background N deposition: the N addition effects are smaller in areas with high N deposition than in areas with low N deposition, despite the fact that the highest N deposition in this study can be considered moderate from an international perspective. The results are important when assessing the reliability of results from N addition experiments on forest floor vegetation in areas with moderate to high background N deposition. We conclude that the interacting effects of N addition and N deposition need to be included when assessing long-term N sensitivity of plant communities.     

Have grass carp driven declines in macrophyte occurrence and diversity in the Vaal River,South Africa?

The Vaal River, South Africa, historically had a rich diversity of native submerged macrophytes with at least 13 species from 5 families recorded. Over the past 10 years there has been a noticeable reduction in the occurrence and diversity of submerged macrophytes in the river. It is possible that this is linked to the recent increase in the populations of invasive alien grass carp Ctenopharyngodon idella Cuvier & Valenciennes (Cyprinidae) in the river, where populations have been a concern since 2005. Grass carp invasions worldwide have been shown to have severe impacts on macrophyte biodiversity and ecosystem functioning. This fish is an aggressive feeder on submerged macrophytes, as well as being an ecosystem engineer that can change water and sediment chemistry.     

Does invasion by an alien plant species affect the soil seed bank?

Questions: How does invasion affect old‐field seed bank species richness, composition and density? How consistent are these effects across sites? Does the soil seed bank match vegetation structure in old‐fields? Location: Menorca, Balearic Islands, Spain, western Mediterranean basin. Methods: We monitored seed germination in soils from old‐fields that were both uninvaded and invaded (legacy effect) by the annual geophyte Oxalis pes‐caprae. We also added O. pes‐caprae bulbs to uninvaded soils to test O. pes‐caprae interference with seedling emergence (competitive effect). We compared species composition in the seed bank with that of the vegetation. Results: Species richness in the seed bank and in the vegetation was not significantly different between invaded and uninvaded areas. Uninvaded areas did not have larger seed banks than invaded areas. More seedlings, especially of geophytes, emerged when O. pes‐caprae bulbs were added to the soil. Species similarity between invaded and uninvaded areas was higher in the seed bank (74%) than in the vegetation (49%). Differences in species composition were as important as differences among sites. The degree of species similarity between the seed bank and the vegetation was very low (17%). Conclusions: Despite invasion by O. pes‐caprae not affecting species richness, the variation in the seed bank species composition in invaded and uninvaded areas, and the differences between the seed bank and the mature vegetation, highlights that even if the invader could be eradicated the vegetation could not be restored back to the exact composition as found in uninvaded areas.     

Hydrologic balance,net primary productivity and water use efficiency of the introduced exotic Eucalyptus grandis × Eucalyptus urophylla plantation in south-western China

Aims Land cover changes can disrupt water balance and alter the partitioning of precipitation into surface runoff, evapotranspiration and groundwater recharge. The widely plantedEucalyptustrees in south-western China have the potential to bring about hydrologic impacts. Our research aims to elucidate the hydrologic balance characteristics of the introduced exoticEucalyptus grandis×Eucalyptus urophyllaplantation and to assess whether its high productivity results from high water use efficiency (WUE) or large water consumption.     

Does artificial snow production affect soil and vegetation of ski pistes? A review

The production of artificial snow and the use of snow additives in ski resorts have increased considerably during the last 20 years. Their ecological consequences are the subject of environmental concerns. This review compiles studies about the ecological implications of ski pistes preparation in general and of artificial snow production. The main direct impacts of ski piste preparation on the vegetation are related to the compaction of the snow cover, namely the induction of soil frost, the formation of ice layers, mechanical damage and a delay in plant development. The vegetation reacts with changes in species composition and a decrease in biodiversity. Artificial snowing modifies some of these impacts: The soil frost is mitigated due to an increased insulation of the snowpack, whereas the formation of ice layers is not considerably changed. The mechanical impacts of snow-grooming vehicles are mitigated due to the deeper snow cover. The delay of the vegetation development is enhanced by a considerably postponed snowmelt. Furthermore, artificial snowing induces new impacts to the alpine environment. Snowing increases the input of water and ions to ski pistes, which can have a fertilising effect and hence change the plant species composition. Increasingly, snow additives, made of potentially phytopathogenic bacteria, are used for snow production. They enhance ice crystal formation due to their ice nucleation activity. Although sterilised, additives affected the growth of some alpine plant species in laboratory experiments. Salts are applied not only but preferably on snowed pistes to improve the snow quality for ski races. The environmental impacts of most salts have not yet been investigated, but a commonly used nitrate salt has intense fertilising properties. Although snowing mitigates some of the negative impacts of ski piste preparation in general, new impacts induced by snowing could be non-beneficial to the vegetation, which, however, has yet to be clarified.     

Does lemming winter grazing impact vegetation in the Canadian Arctic?

In low-productivity environments such as the tundra, it has been proposed that regular, multi-annual population cycles of lemmings could be driven by winter food depletion in years of peak abundance. If lemming population dynamics is controlled by food resources, we predict that (1) winter grazing should negatively impact the abundance of food plants, (2) this impact should be proportional to lemming density and (3) high lemming winter grazing pressure should result in reduced plant growth during the following summer. We tested these predictions on Bylot Island, Nunavut, Canada, where two species of lemmings are present: the brown (Lemmus trimucronatus) and collared lemming (Dicrostonyx groenlandicus). We installed 16 exclosures in their preferred wintering habitat (snowbeds) and annually sampled plant biomass inside and outside exclosures at snow melt and at peak growth during the summers of 2009–2012, covering a full population cycle. Winter grazing had no impact on total vascular plant or moss biomass at snow melt in all years. Among plant families, only Caryophyllaceae, which was uncommon, showed a decline. In moss taxa, a negative effect was found on Polytrichum in only 1 year out of three. Overall, plant regrowth during the subsequent summer showed annual variation and tended to be reduced in the 2 years of high lemming abundance. However, this could be a consequence of summer grazing. Overall, the impact of lemming winter grazing on plants was weak and short-lived, even in years of high lemming abundance. Therefore, our results are not consistent with the hypothesis that food depletion during winter was the cause of the lemming decline following peak abundance at our study site. Other factors may limit lemming populations and prevent them from reaching densities high enough to exhaust their food resources.     

Does seminal plasma affect angiogenesis in the porcine oviduct?

In the present study we examined the effect of seminal plasma (SP) on angiogenesis in the porcine oviduct. Gene expressions of vascular endothelial growth factor (VEGF) and its two receptors (Flt-1: fms-like tyrosine kinase and Flk-1/KDR: fetal liver kinase-1/kinase insert domain-containing receptor) as well as fibroblast growth factors (FGF-1 and 2) and von Willenbrand factor (VWF) were determined in the oviduct of SP-treated and control (PBS-treated) gilts. Moreover, vascular density (VD) indicated by endothelial cell area immunolocalized by VWF staining, was assessed in the oviducts. Real-time PCR revealed significantly higher expression of FGF-2 and VWF on day 1 (p < 0.05) after SP administration in comparison to control animals. In contrast, Flt-1 mRNA level on day 1 was lower in SP-treated gilts compared to controls (p < 0.05). In the examined oviductal sections, VD did not differ between control and SP-treated animals. However, in SP-treated animals VD was higher on day 5 than on day 1 (p < 0.05) or 3 (p < 0.01). SP had no significant effect on VEGF, Flk-1/KDR and FGF-1 mRNA expression. In conclusion, our results suggest that SP affects the vascular network by changing the expression of factors contributing to angiogenesis.     

Does smoking affect body weight and obesity in China?

An inverse relationship between smoking and body weight has been documented in the medical literature, but the effect of cigarette smoking on obesity remains inconclusive. In addition, the evidence is mixed on whether rising obesity rates are an unintended consequence of successful anti-smoking policies. This study re-examines these relationships using data from China, the largest consumer and manufacturer of tobacco in the world that is also experiencing a steady rise in obesity rates. We focus on the impact of the total number of cigarettes smoked per day on individuals’ body mass index (BMI) and on the likelihood of being overweight and obese. Instrumental variables estimation is used to correct for the endogeneity of cigarette smoking. We find a moderate negative and significant relationship between cigarette smoking and BMI. Smoking is also negatively related to being overweight and obese, but the marginal effects are small and statistically insignificant for being obese. Quantile regression analyses reveal that the association between smoking and BMI is quite weak among subjects whose BMIs are at the high end of the distribution but are considerably stronger among subjects in the healthy weight range. Ordered probit regression analyses also confirm these findings. Our results thus reconcile an inverse average effect of smoking on body weight with the absence of any significant effect on obesity. From a policy perspective these findings suggest that, while smoking cessation may lead to moderate weight gain among subjects of healthy weight, the effects on obese subjects are modest and should not be expected to lead to a large increase in obesity prevalence rates.     

Introduction and invasion of common myna (Acridotheres tristis) in Kruger National Park,South Africa: still time for action?

Biological Invasions - Common myna (Acridotheres tristis) is a passerine bird native to south-east Asia, established as an alien in many parts of the world including South Africa, where it is...     

Species–area relationships in the Hantam-Tanqua-Roggeveld,Succulent Karoo,South Africa

The Hantam-Tanqua-Roggeveld subregion is part of the Succulent Karoo hotspot of biodiversity which stretches along the southwestern side of South Africa and Namibia. Forty Whittaker plots were surveyed in the spring of 2005, in eight vegetation associations, to gather diversity data for the Hantam, Tanqua Karoo and Roggeveld areas. Seven plot sizes were used to construct species–area curves using three different models namely: the untransformed linear function, the power function and the exponential function. In general, the power and exponential functions produced a more significant fit to the data than the untransformed linear function. Linear regressions using environmental parameters indicated that altitude, mean annual precipitation and mean annual temperature were significant predictors of species richness at the 1, 10, 100 and 1000 m² scales. To illustrate the variation in species–area curves and species richness across the landscape, a transect through the study area is discussed. The transect stretches eastwards from the Tanqua Karoo across the escarpment into the Roggeveld and crosses five different vegetation associations. Differences between associations were found in species richness in the 1000 m² plots. Each association also produced species–area curves with their own characteristics. Slope values for the samples within an association did not differ significantly, although the intercept value often did. Comparisons between associations along the transect revealed significant differences in the slope value between the associations, except for the Dicerothamnus rhinocerotis Mountain Renosterveld which did not differ significantly from the associations bordering it on either side.     

Does isolation affect phenotypic variability and fluctuating asymmetry in the endangered Red Apollo?

Isolated populations represent one of the main focuses in conservation biology. Long-term isolation often causes losses of genetic diversity and as a consequence might reduce individual fitness. Morphometric characters can be used as suitable markers to analyse ecological stress and individual fitness of local populations. Asymmetry in bilateral symmetry is used as a measure for developmental instability of populations and is often negatively correlated with population size and low genetic diversity. As a study system, we selected the endangered butterfly Parnassius apollo, which occurs in small and isolated remnant populations in Central Europe, but also in fairly large metapopulations in the Alps. We analysed wing morphometrics (shape and size characters) of 812 individuals representing (1) already extinct, (2) highly isolated and (3) still interconnected populations. Seventeen landmarks on veins were used to analyse morphological variances in the wing shape. Our data show significant deviations between landmarks on the left and right wing side within individuals and strong morphological variance among individuals. The highest morphological variability could be found for individuals in the Alps, however, the level of asymmetry was very similar for all populations analysed. The higher morphological variability found in the Alps can be interpreted as a consequence of the higher level of the genetic diversity detectable for this region. Analysis on morphological variance of P. apollo individuals of the Mosel valley using time series ranging from 1895 until today showed no significant rise in asymmetry and no decline of morphological variability over time, although, anthropogenic habitat destruction has caused severe bottlenecks in this population.     

Is Younger Really Safer? A Qualitative Study of Perceived Risks and Benefits of Age-Disparate Relationships among Women in Cape Town,South Africa

Young women in age-asymmetric relationships may be at an elevated risk for acquisition of HIV, since relationships with older men are also correlated with other risk behaviors like less condom use. Qualitative studies have shown that women are motivated to participate in these relationships for money and emotional support. However, there is a paucity of research on women’s perceived risks of these relationships, particularly in South Africa. To this end, we conducted in-depth interviews with 23 women recruited from three urban communities in Cape Town. A thematic question guide was used to direct the interviews. Thematic content analysis was used to explore women’s perceived risks of age-disparate and non-age-disparate relationships, the benefits of dating older men, and risk perceptions that influence decisions around beginning or ending a relationship. A plurality of women thought that dating an older man does not bring any adverse consequences, although some thought that older men do not use condoms and may be involved in concurrent partnerships. Many women were less inclined to date same-age or younger men, because they were viewed as being disrespectful and abusive. This study points to the need for more awareness raising about the risks of age-disparate relationships. In addition to these initiatives, there is an urgent need to implement holistic approaches to relationship health, in order to curb intimate partner violence, improve gender equity and make non-age-disparate relationships more attractive.     

Can the use of natural biostimulants be a potential means of phytoremediating contaminated soils from goldmines in South Africa?

Biostimulants offer great potential in improving phytoremediation of contaminated soils. In the current greenhouse-based study, Brassica juncea seedlings grown on soils collected from Krugersdorp Goldmine and the adjourning areas (a Game Reserve and private farmland) were supplemented with different biostimulants (Kelpak® = KEL, vermicompost leachate = VCL, smoke-water = SW). Indole-3-butyric acid (IBA) was included in the study for comparative purposes because these biostimulants are known to enhance rooting. Prior to the pot trial, concentrations of elements in the three soil types were determined using Inductively Coupled Plasma-Optical Emission Spectroscopy. Plants were harvested after 105 days and the growth and concentrations of elements in the various plant organs were determined. TheB. juncea seedlings with and without biostimulants did not survive when growing in soil from the Krugersdorp Goldmine. The Game Reserve and private farmland soils supplemented with KEL produced the highest plant biomass and the lowest accumulation of metals in the organs of B. juncea. High concentrations (>13 000 mg kg^?1) of zinc and aluminium were quantified in the roots of IBA-supplemented soils from the Game Reserve. Generally, IBA and SW enhanced the phytoremediation of B. juncea due to elevated levels of elements that accumulated in their different organs.     

Does aerobic and strength exercise sequence in the same session affect the oxygen uptake during and postexercise?

Concurrent training is a strategy employed in both general fitness and sports conditioning. The purpose of this study was to compare the responses of VO2 in different combinations of strength exercise with aerobic interval exercise. Eight men (23.6 ± 4.2 years, 178 ± 6.3 cm, 77 ± 7.9 kg, 7.67 ± 1.95% body fat) completed 3 combinations of strength training (ST) and aerobic training (AT) in a randomized order with a 7-day recovery period: AT before ST exercises, AT between 2 blocks of ST exercises, and AT after ST exercises. The ST comprised 4 exercises performed in 3 sets of 10 reps and 2 exercises, abdominal crunch and lumbar extension, performed in 3 sets of 30 and 20 reps, respectively. The AT consisted of a 20-minute interval cycling. There were no significant differences in the values of absolute or relative VO2, in the heart rate (HR) and in the respiratory exchange ratio (RER) when the 3 sessions (during + postexercise measurements) were compared (values are mean ± SD). Analyzing only ST in each session, differences were detected in the RER values (F = 4.714; p < 0.05; η2 = 0.308) between AT before ST and AT in the middle of ST (1.01 ± 0.97 vs. 1.11 ± 0.07, respectively). In all sequences, there was a significant increase (p < 0.05) in the values of relative and absolute VO2 and HR, and a significant decrease in RER values (p < 0.05) from the first to the second part of the ST session. The values of absolute or relative VO2, HR, and RER did not vary significantly among the 3 sessions as compared with the AT after ST. These data support the hypothesis that ST and AT, when performed in sequence in the same session, do not seem to affect the overall oxygen consumption during the exercise session. Therefore, training sessions may incorporate both modalities without apparent impact on aerobic exercise.