Do grazers alter nitrogen dynamics on grazing lawns in a South African savannah?

The presence of grazers on grazing lawns in East Africa and North America often alters nitrogen cycling and availability. Grazing lawns can be defined as areas where grasses are kept in a short, actively growing, palatable state by the action of grazers. Our aim was to test whether lawns have enhanced leaf nitrogen (N) concentrations, total soil N and δ¹⁵N when compared to tall grass areas in a South African savannah. Previous studies have used ecosystem δ¹⁵N as a proxy of N availability, and enriched δ¹⁵N values have been suggested to indicate higher N availability or higher N transformation rates. Across all sites, foliar N concentrations (but not soil N) were higher when compared to tall grass areas, and evidence of enriched foliar and soil δ¹⁵N values was found on the lawns. These results suggest that grazers may be involved in altering the rates of N transformations directly on grazing lawns. Regardless of whether these N transformations included increased net N mineralization, higher N concentrations in above‐ground foliage attract grazers back to the lawns, encouraging their maintenance.     

Influence of Colophospermum mopane canopy cover on litter decomposition and nutrient dynamics in a semi‐arid African savannah

The objective of this study was to investigate the influence of mopane canopy cover on litter decomposition in a semi‐arid African savannah. We used a randomized block design with five blocks of 100 × 100 m demarcated in a 10‐ha pocket of open mopane woodland. Litterbags were placed beneath large (8.3 m crown diameter) and small mopane trees (2.7 m crown diameter) and in the intercanopy area. Decomposition was fastest in the intercanopy area exposed to solar radiation (k = 0.35 year^?1), intermediate beneath small trees (k = 0.28 year^?1) and slowest beneath large trees (k = 0.23 year^?1). Soil temperatures beneath small and large trees were 3–5 and 6–9°C lower than in the intercanopy area, respectively. Bacterial and fungal counts were significantly higher (P < 0.05) beneath large than small trees and in the intercanopy area. The amount of N and P released did not vary significantly among sampling sites. Soil moisture in the dry season was similar among sampling sites but rainy‐season soil moisture was significantly greater (P < 0.05) beneath large than small trees and in the intecanopy area. Mopane canopy cover retarded litter decomposition suggesting that photodegradation could be an important factor controlling carbon turnover in semi‐arid African savannahs.     

Weak conspecific feedbacks and exotic dominance in a species-rich savannah

Whether dominance drives species loss can depend on the power of conspecific self-limitation as dominant populations expand; these limitations can stabilize competitive imbalances that might otherwise cause displacement. We quantify the relative strength of conspecific and heterospecific soil feedbacks in an exotic-dominated savannah, using greenhouse trials and field surveys to test whether dominants are less self-suppressed, highly suppressive of others or both. Soil feedbacks can impact plant abundance, including invasion, but their implications for coexistence in invader-dominated systems are unclear. We found that conspecific feedbacks were significantly more negative than heterospecific ones for all species including the dominant invaders; even the rarest natives performed significantly better in the soils of other species. The strength of these negative feedbacks, however, was approximately 50 per cent stronger for natives and matched their field abundance--the most self-limited natives were rare and narrowly distributed. These results suggest that exotics dominate by interacting with natives carrying heavier conspecific feedback burdens, without cultivating either negative heterospecific effects that suppress natives or positive ones that accelerate their own expansion. These feedbacks, however, could contribute to coexistence because all species were self-limited in their own soils. Although the net impact of this feedback stabilization will probably interact with other factors (e.g. herbivory), soil feedbacks may thus contribute to invader dominance without necessarily being detrimental to species richness.     

福州左海公园园林绿化调查及种类配置分析

本文对福州左海公园园林植物种类及其配置进行统计、描述,测算其绿化面积及绿化率,分析种类配置的合理性,并提出可行性建议。     

浙江温州洞头国家海洋公园药用植物资源多样性调查

本研究采用样线调查法和踏查法相结合的方式对浙江温州洞头国家海洋公园药用植物资源进行调查研究。此次调查涉及14个岛屿共计23条样线,统计到药用植物共99科282属400种。结果表明：禾本科（Poaceae）和菊科（Asteraceae）为该区内的优势科;药用种子植物以热带成分为主;生活型以多年生草本植物为主,共计157种;药性以平性居多,有50科101属122种;入药部位以全草或全株入药为主,有64科160属221种;药效包含20个大类,其中以清热药为主,有55科97属115种;药用植物中有毒植物共计70种,隶属于31科54属;药用植物中有75种植物和77味中药被药典收载;共3种药用植物被列入世界自然保护联盟（IUCN）的受威胁评估等级,分别是全缘贯众（Cyrtomiumfalcatum）、黄檀（Dalbergiahupeana）和福参（Angelicamorii）,并有2种药用植物列入濒危动植物种国际贸易公约,分别是葱叶兰（Microtisunifolia）和绶草（Spiranthessinensis）。在药用植物中发现1种国家二级重点保护野生植物：金荞麦（Fagopyrumdibotrys）和3种浙江省重点保护野生植物：龙须藤（Bauhiniachampionii）、三叶崖爬藤（Tetrastigmahemsleyanum）和柃木（Euryajaponica）。本研究旨在为该区域中药材产业的发展提供先导资料,并为海岛药用植物的开发和利用奠定基础。     

深圳塘朗山郊野公园的植物资源

广东深圳塘朗山郊野公园共有野生维管植物144科423属611种,分别占广东省维管植物280科1589属5737种的51.4%、26.7%和10.65%;其中蕨类省植物21科29属33种,裸子植物3科3属4种,被子植物120科391属574种,被子植物占绝对优势。国家重点保护野生植物共计7科7属7种,占广东省国家重点保护野生植物的10.9%;珍稀濒危植物有4科5属5种,占广东省珍稀濒危植物67种的7%。公园中经济植物可分为12类,分别是药用植物321种,用材树种65种,观赏植物60种,纤维植物41种,野生水果33种,油脂植物38种,饲料植物42种,鞣料植物42种,野菜植物25种,农药植物27种,芳香植物26种,淀粉植物23种,保健植物19种,染料植物13种,有毒植物10种,蜜源植物5种。     

The regressive Cirsium rivulare population in an unmown meadow in Białowieża National Park: Influenced by other clonal plants and necromass

This study deals with population dynamics of Cirsium rivulare (brook thistle) present in a meadow that undergoes succession as a result of former disuse. The effect of the following in the succession, currently dominant clonal species and necromass on the performance of the brook thistle population (presence, size of clusters and reproduction) was investigated. The regression stage, the Cirsium rivulare population had attained after mowing, was discontinued. Different kinds of influence from the contiguous species on the brook thistle population could be identified. In the case of Filipendula ulmaria and Carex cespitosa, Cirsium rivulare clusters were found to be present on the edge of the dominant patches. In case of Carex acutiformis patches brook thistle ramets did not form clusters but were present among the sedge ramets. No Cirsium rivulare ramets were found in Phragmites australis and willow (Salix cinerea, S. pentandra and S. aurita) patches. The highest number of generative brook thistle ramets were observed in a Carex acutiformis patch, whereas the highest number of inflorescences on the shoots of the analysed species were identified in the patch dominated by Filipendula ulmaria.Experimental vegetation gaps were created in patches dominated by various species to determine the effect of necromass on the presence of Cirsium rivulare seedlings. A considerable rise in the number of Cirsium rivulare seedlings was noted in Carex acutiformis and Filipendula ulmaria patches following necromass removal in comparison with plots containing necromass. On the other hand, removing the necromass and foliage did not contribute to an increase in the numbers of brook thistle seedlings in the patch dominated by Cirsium rivulare itself.     

Children’s knowledge and contact with native fauna: a comparative study between Portugal and Spain

ABSTRACT

The present study compared Portuguese and Spanish children in the 6^th year of primary school in terms of their knowledge and live experience of animals from the Iberian Peninsula (IP) and the African savannah. A questionnaire was administered to 420 children from state schools, 215 from Portugal and 205 from Spain. The questionnaire included photos of eleven mammals from each region. The pupils had to identify them, to say if they had observed them live and where, and if they are native in the IP. The results showed a greater knowledge of both groups of the savannah species, also the ones most had seen live. However, the Spanish children had a better performance in the identification of the native mammals and which animals are native on IP, probably because these children are from a less urban zone, with more direct contact with some of the species presented. The school does not seem to play, in either group, an important role in the learning about native species. Boys from both countries performed better than girls on the issues under study. A high percentage of children from both countries think that several of the savannah species occur wild on the IP.     

祁连山国家公园青海片区野生植物资源调查

该研究以祁连山国家公园青海片区野生植物资源为研究对象,通过样方调查法对祁连山国家公园青海片区野生植物资源的种属分类情况进行调查,共记录野生植物资源130种,隶属于37科84属。其中,野生药用植物95种,隶属于34科66属;国家Ⅱ级保护植物7种,隶属于3科6属;易危种3种,隶属于3科3属。该研究结果可为祁连山国家公园青海片区野生植物资源普查、合理开发利用、生物多样性研究及保护策略的制定奠定理论基础。