The Evolving Role of Botanical Gardens and Natural Areas:A Floristic Case Study from Royal Botanical Gardens,Canada

As leaders calling for the conservation of the world’s plants,botanical gardens protect plants within living collections.Many also study,manage and restore plants in natural habitats.Royal Botanical Gardens(Ontario,Canada) has integrated both horticultural and natural heritage in its mission for decades.Envisioned by municipal leaders in the 1920s as a combination of nature sanctuaries and civic gardens,RBG now includes forests,wetlands and other habitats,gardens and built spaces.Today RBG is Canada’s largest botanical garden on the basis of area.In the 1950s RBG began to inventory plant diversity.The checklist of spontaneous vascular plants now exceeds 1 170 species,of which 752 are native.This is 37% of Ontario’s native vascular plants and 19% of the native vascular flora of Canada.The RBG nature sanctuaries are among the richest locations in Canada for species-level diversity.We examine the history of floristic exploration within RBG and compare plant species-area relationships among protected natural areas in Ontario.This comparison supports the contention that the nature sanctuaries,and in particular Cootes Paradise,could be considered an important area for plants in Canada,and relative to the nation’s flora,a biodiversity hotspot.The fact that a candidate vascular plant hotspot for Canada lies within a major botanical garden presents opportunities for raising public awareness of the importance of plant diversity,as well as focusing attention on the scientific and conservation biology needs of communities and individual species in this area.     

Analysis of forestry impacts and biodiversity in two Pyrenean forests through a comparison of moth communities （Lepidoptera, Heterocera）

We have compared the biodiversity variations in moth communities between unmanaged forests and commercial forests in a mountainous environment （Pyrenees France）. The aim was to evaluate the impact of forestry activities on moth diversity. The data collected from the insects were analysed with a Bayesian specific similarity index （noted SSP index） and by statistical biodiversity indexes comparison. It was seen that diversity and richness were decreased in the plantation compared to the unmanaged forest. Interestingly, the composition of the communities of moths was shown to be not only related to the presence/absence of host plants, but also to be in relation with changes in the differences in forest architecture （i.e. the relative coverage by the different vegetation levels）. However, the moth community in the commercial forest still has a high capacity to converge with the moth community present in more natural forests. We report here a list of 177 species of moths, providing information on the distribution of some uncommon species, poorly studied as yet in the Pyrenees.     

Effects of fire disturbance on the soil physical and chemical properties and vegetation of Pinus massoniana forest in south subtropical area

A variety of studies on the impact of fire disturbance on ecosystems has shown that the physical and chemical properties of soil after fire disturbance change notably. Meanwhile, little is known about the effects of different fire intensities on the soil properties and vegetation after fire disturbance, especially in the south subtropical area. In this paper, we analyzed the soil physical and chemical properties, vegetation species and species diversity of fire center, fire edge (which was burned a year ago) and non-burned Pinus massoniana plantation in Gaoyao, Guangdong province, China. The results showed that the soil conductivity, water content, total nitrogen, total potassium, and available potassium content of fire center were significantly higher than those of the non-burned land, and pH was higher than that of fire edge, whereas the available nitrogen, total phosphorus and organic matter content were much lower, which were generally existed in 0–10 cm soil layer and 10–30 cm soil layer. Changes of the soil properties of fire edge were similar with those of fire center, but less significant, and seemed to be more complex. Effects of burning on the vegetation of fire disturbance plots were found to be notable, species number and average height of plants of fire disturbance plots were lower than those of the non-burned plots, a difference of species diversity and uniformity were also shown, and finally, the composition of plant community also changed, e.g., pioneer species such as D. dichotoma, etc., dominated, and drought-resistant plants, heat-resistant plants and positive plants increased after burning.     

Response of Polygonum viviparum species and community level to long-term livestock grazing in alpine shrub meadow in Qinghai-Tibet Plateau

Grazing by domestic herbivores is generally recognized as a major ecological factor and an important evolutionary force in grasslands. Grazing has both extensive and profound effects on individual plants and communities. We investigated the response patterns of Polygonum viviparum species and the species diversity of an alpine shrub meadow in response to long-term livestock grazing by a field manipulative experiment controlling livestock numbers on the Qinghai-Tibet Plateau in China. Here, we hypothesize that within a range of grazing pressure, grazing can alter relative allocation to different plant parts without changing total biomass for some plant species if there is life history trade-offs between plant traits. The same type of communities exposed to different grazing pressures may only alter relative species' abundances or species composition and not vary species diversity because plant species differ in resistant capability to herbivory. The results show that plant height and biomass of different organs differed among grazing treatments but total biomass remained constant. Biomass allocation and absolute investments to both reproduction and growth decreased and to belowground storage increased with increased grazing pressure, indicating the increasing in storage function was attained at a cost of reducing reproduction of bulbils and represented an optimal allocation and an adaptive response of the species to long-term aboveground damage. Moreover, our results showed multiform response types for either species groups or single species along the gradient of grazing Intensity. Heavy grazing caused a 13.2％ increase in species richness. There was difference in species composition of about 18％--20％ among grazing treatment. Shannon-Wiener (H') diversity index and species evenness (E) index did not differ among grazing treatments. These results support our hypothesis.     

Plant community complexity in the arid valley of Minjiang River, southwestern China

Biocomplexity theory is becoming increasingly important in understanding natural vegetation dynamics and interrelation among all components of the ecosystem. In this study, based on the field investigation of plant species and environmental factors (altitude, microtopography, soil water content, and soil nutrients) in an arid valley of the upper reaches of Minjiang River, Sichuan Province, southwestern China, plant community complexity and its relationship with environmental factors, community diversity, species evenness and richness were studied. Both total and structural complexities of the communities showed a “high- low-high” tendency with the increase in altitude of the area, which meant that the complexity of communities was the highest at the sites of low and high altitude, whereas it was the lowest at the sites of intermediate altitude. It was found that the total community complexity had significant quadratic correlations with soil organic matter (SOM) content, total nitrogen (N), hydrolyzable N, soil water content, and available potassium (K), whereas it had no significant correlations with soil total K, total phosphorus (P), available P, and pH value. The total community complexity positively correlated with community diversity, species evenness and species richness, whereas the structural complexity negatively correlated with the community evenness. Of the two components of the total community complexity, namely, the structural complexity and the structural diversity, the structural complexity was more sensitive than the structural diversity to the changes of species in the community, which was not only related to the community evenness but also to the community richness. The relative contribution of both the structural complexity and the structural diversity to the total complexity would be different for different study areas or ecosystems.     

Effects of fire disturbance on the soil physical and chemical properties and vegetation of Pinus massoniana forest in south subtropical area

A variety of studies on the impact of fire disturbance on ecosystems has shown that the physical and chemical properties of soil after fire disturbance change notably. Meanwhile, little is known about the effects of different fire intensities on the soil properties and vegetation after fire disturbance, especially in the south subtropical area. In this paper, we analyzed the soil physical and chemical properties, vegetation species and species diversity of fire center, fire edge (which was burned a year ago) and non-burned Pinus massoniana plantation in Gaoyao, Guangdong province, China. The results showed that the soil conductivity, water content, total nitrogen, total potassium, and available potassium content of fire center were significantly higher than those of the non-burned land, and pH was higher than that of fire edge, whereas the available nitrogen, total phosphorus and organic matter content were much lower, which were generally existed in 0–10 cm soil layer and 10–30 cm soil layer. Changes of the soil properties of fire edge were similar with those of fire center, but less significant, and seemed to be more complex. Effects of burning on the vegetation of fire disturbance plots were found to be notable, species number and average height of plants of fire disturbance plots were lower than those of the non-burned plots, a difference of species diversity and uniformity were also shown, and finally, the composition of plant community also changed, e.g., pioneer species such as D. dichotoma, etc., dominated, and drought-resistant plants, heat-resistant plants and positive plants increased after burning.     

Nestedness of waterbird assemblages in the subsidence wetlands recently created by underground coal mining

Nestedness has been a research focus in fields of island biogeography and community ecology in recent decades. Although nestedness of faunal assemblages has been investigated in natural wetlands, it remains largely unknown whether and why waterbird communities in artificial wetlands follow n ested patter ns. We exami ned the existence of n ested ness and un derlyi ng drivers in waterbird comm un ities in subside nee wetlands that are recently created by large-scale un derground coal mining in the North China Plain. Twelve point-count surveys for waterbirds were undertaken approximately every 2 weeks in 55 subside nee wetla nds from September 2016 to April 2017. We used the metric WNODF to estimate nestedness of the assemblages. Partial Spearman rank correlations were performed to examine the association between the nestedness and habitat variables (wetland area, landscape connectivity, wetland age, and habitat diversity) as well as life-history traits (body size, clutch size, dispersal ratio, geographical range size, and migrant status) related to species exti notion risk and colon izati on rate. Waterbird assemblages in the subside nee wetla nds were significantly nested. After controlling for other independent variables, the magnitude of nestedness was significantly and negatively correlated with wetland area and species trait linked to extinction risk (i.e., geographical range size). Our results indicate that selective extinction may be the main driver of the nestedness of waterbird assemblages in our study system. However, the nestedness was not due to passive sampling, selective colonization, or habitat diversity. From a conservation viewpoint, both large wetlands and waterbirds with a small geographic range should be protected to maximize the preserved species richness.     

Human activities and nitrogen in waters

Shenzhen was a famous typical rapid-urbanization city in China, and this study compares plant species diversity in urban parks from the start of urbanization through 2011. Results show that the plant species biodiversity increased rapidly: the rate changed from 140% to 980% and the average increasing rate was 406.90%, but only 12.59% of plants spread into the park naturally. Shrubs had the highest rate; with change increasing from 20.70% to 43.54%, they replaced trees to become the dominant type. The biodiversity of native plants also increased, but their proportion relative to all species had declined. The homogenization of plant species in the parks increased; more than half of the plant species (62.24%) are located in 5–7 parks at once now, compared with 65.52% of species located in only 2–3 parks at the start of the study. The increase of species was faster than the increase of families; many new species planted belong to a few specific families. The ratio of species to families declined from 0.40 to 0.32. Results indicate that the rapid increase of plant species diversity as well as their homogenization happened in the initial stage of urbanization, and so rapid urbanization might be the major factor in the changes in plant species diversity in municipal parks. Rapid urbanization was an important cause of change in plant species diversity.     

Effect of rapid urbanization on plant species diversity in municipal parks, in a new Chinese city: Shenzhen

Shenzhen was a famous typical rapid-urbanization city in China, and this study compares plant species diversity in urban parks from the start of urbanization through 2011. Results show that the plant species biodiversity increased rapidly: the rate changed from 140% to 980% and the average increasing rate was 406.90%, but only 12.59% of plants spread into the park naturally. Shrubs had the highest rate; with change increasing from 20.70% to 43.54%, they replaced trees to become the dominant type. The biodiversity of native plants also increased, but their proportion relative to all species had declined. The homogenization of plant species in the parks increased; more than half of the plant species (62.24%) are located in 5–7 parks at once now, compared with 65.52% of species located in only 2–3 parks at the start of the study. The increase of species was faster than the increase of families; many new species planted belong to a few specific families. The ratio of species to families declined from 0.40 to 0.32. Results indicate that the rapid increase of plant species diversity as well as their homogenization happened in the initial stage of urbanization, and so rapid urbanization might be the major factor in the changes in plant species diversity in municipal parks. Rapid urbanization was an important cause of change in plant species diversity.     

Body Surface Area Prediction in Odorrana grahami

Body surface area（BSA）was regarded as a more readily quantifiable parameter relative to body mass in the normalization of comparative biochemistry and physiology.The BSA prediction has attracted unceasing research back more than a century on animals,especially on humans and rats.Few studies in this area for anurans were reported,and the equation for body surface area（S）and body mass（W）：S=9.9 W 0.56,which was concluded from toads of four species in 1969,was generally adopted to estimate the body surface areas for anurans until recent years.However,this equation was not applicable to Odorrana grahami.The relationship between body surface area and body mass for this species was established as：S=15.4 W 0.579.Our current results suggest estimation equations should be used cautiously across different species and body surface area predictions on more species need to be conducted.     

炼山飞播造林后华山松林主要种群资源利用研究

巫溪县红池坝地区于1972年采用炼山造林的生态恢复措施对退化森林植被进行了恢复与重建,现已形成了多种类型的华山松(Pinusarmandii)针阔混交林群落.采用Petraitis生态位普遍重叠和特定重叠指数,研究了巫溪县红池坝地区华山松群落中10个主要乔木种群的资源利用状况.结果表明,华山松与大多数乡土树种都具有较大的生态位宽度,种间普遍重叠值为0.728,表明种群能够充分、有效地占有和利用生境资源.华山松对乡土树种的种间特定重叠值很小,而乡土树种对华山松的特定重叠值大,华山松对资源利用和竞争能力不及乡土树种,在竞争中处于劣势.乡土阔叶树种间特定重叠值普遍很小,在资源利用上生态位分化有明显优势,因此,乡土树种的生态位特征应作为植被生态恢复与重建实施过程中的有益参照.另外,本文还对Petraitis的重叠测度指数的可用性和优缺点进行了初步探讨.     

外来红树植物无瓣海桑引种及其生态影响

无瓣海桑是我国首个从国外引进并大面积推广种植的红树植物,生长快,适应性强,已成为华南沿海红树林恢复造林的主要树种。但近年来无瓣海桑引种已引起较大争论,焦点是无瓣海桑是否会对乡土红树植物生长产生不利影响,是否会造成生态入侵,是否应限制推广种植。根据引种以来的研究成果,对无瓣海桑的生态适应性、种植技术、生产力与物质循环、生态影响等四个方面的引种研究进行综述;分析无瓣海桑引种对乡土红树植物生长的影响和生态入侵可能性,对无瓣海桑引种造林提出建议。指出今后无瓣海桑引种的的研究重点为:无瓣海桑引种的生态监测与入侵评估;对滩涂水生生物的影响;与乡土红树植物优化配置的混交种植技术;无瓣海桑的资源化利用。     

秦岭水灾迹地油松和华山松更新种群数量特征

 不同植物种群种间比较研究利于揭示种群的形成机制和影响因素。该文研究了秦岭地区蔡玉河流域范家庄段水灾迹地恢复17年后群落优势种油松(Pinus tabulaeformis) 和华山松(P. armandii)的种群数量特征。水灾灾后第一年（1989年）就有油松和华山松个体进入迹地,由于较大的高生长速度和侧生长速度,油松种群的平均高度和地径高于华山松,占据了较大的垂直和水平空间。相对来说, 油松和华山松高度结构和径级结构模式不同,二者均是小个体数量居多,大个体数量极少,但油松中等大小个体多于华山松。油松和华山松种群的年龄结构模式不同,油松的为单峰右偏曲线,华山松的则近似于正态分布。坡向对油松的年龄结构模式没有影响,但对华山松种 群有影响。油松和华山松种群不同高度级、径级和年龄级之间存在显著正或负相关关系,缺少一致性,表明种群大小结构不一定反映年龄结构。油松和华山松种群的密度动态和存活曲线类型一致,均为Ⅱ型,表明二者具有相同的种群动态。总体上说,油松和华山松具有不同的树种生物学特性,使得种群的大小结构和年龄结构不同,但对种群更新存活动态没有影响。     

柳州市行道树资源调查与结构特征分析

该研究通过对柳州市区主要道路园林绿化全面踏勘,在四城区中筛选出68条道路行道树进行现场调查和综合评价。结果表明:(1)柳州市行道树共有28种,隶属于17科21属,常绿树种与落叶树种比例及乡土树种与外来树种比例合理。(2)柳州市行道树中小叶榕和黄葛榕在各城区应用频度较高,树种组成结构相对单一。(3)季相树种在各城区应用频度不均衡,部分城区春季景观营造效果显著,而夏秋冬季相景观效果不显著。(4)绿化达标率和林荫路推广率离国家生态园林城市还有较大差距,物种丰富度和多样性指数有待提高。建议加大乡土树种的应用与推广,提高各城区物种丰富度及季相树种的应用,营造城市道路特色季相景观。该研究成果提出了发展乡土树种、丰富树种多样性及季相景观营造的技术建议,对柳州市行道树树种规划和建设提供了科学依据。     

Ecological outcomes of agroforests and restoration 15 years after planting

Large‐scale forest restoration relies on approaches that are cost‐effective and economically attractive to farmers, and in this context agroforestry systems may be a valuable option. Here, we compared ecological outcomes among (1) 12–15‐year‐old coffee agroforests established with several native shade trees, (2) 12–15‐year‐old high‐diversity restoration plantations, and (3) reference old‐growth forests, within a landscape restoration project in the Pontal do Paranapanema region, in the Atlantic Forest of southeastern Brazil. We compared the aboveground biomass, canopy cover, and abundance, richness, and composition of trees, and the regenerating saplings in the three forest types. In addition, we investigated the landscape drivers of natural regeneration in the restoration plantations and coffee agroforests. Reference forests had a higher abundance of trees and regenerating saplings, but had similar levels of species richness compared to coffee agroforests. High‐diversity agroforests and restoration plantations did not differ in tree abundance. However, compared to restoration plantations, agroforests showed higher abundance and species richness of regenerating saplings, a higher proportion of animal‐dispersed species, and higher canopy cover. The abundance of regenerating saplings declined with increasing density of coffee plants, thus indicating a potential trade‐off between productivity and ecological benefits. High‐diversity coffee agroforests provide a cost‐effective and ecologically viable alternative to high‐diversity native tree plantations for large‐scale forest restoration within agricultural landscapes managed by local communities, and should be included as part of the portfolio of reforestation options used to promote the global agenda on forest and landscape restoration.     

The community structure of bird assemblages on urban strangler figs

Figs have been regarded as keystone plant resources that support diverse tropical vertebrate frugivore communities. Planting or conserving large fig trees, such as stranglers, have therefore been proposed for enhancing urban biodiversity. We compared the diversity and community structure of bird assemblages on strangler figs with non‐fig urban trees as well as between the fruiting and non‐fruiting fig trees in an urban setting in Singapore. The total bird abundance across all the fig trees when in fruit was 4.5‐fold higher than on non‐fig trees and 3.5‐fold higher than when the same fig trees were not fruiting, but only attracted two more species. On individual trees, after accounting for the presence of mistletoes, tree height, the area covered by buildings, road lane density, and the distance to natural vegetation, mean diversity was not different between non‐fig trees and fig trees when they were not in fruit. On the other hand, when fruiting, each fig tree on average had 1.4 more species, 3 more counts of non‐native birds, and 1.6 more counts of insectivorous birds than when not fruiting. There was significant compositional turnover between non‐fig trees and non‐fruiting fig trees, while community dispersion was significantly lower among fig trees in fruit. Our results demonstrate that fig trees provide fruit and non‐fruit resources for birds in an urban landscape but do not necessarily support more diverse total bird assemblages than non‐fig trees. Instead, bird communities on fruiting urban figs would be highly homogeneous and dominated by a few species. Abstract in Malay is available with online material.     

Vegetation Response Following Invasive Tamarisk (Tamarix spp.) Removal and Implications for Riparian Restoration

Using a retrospective study of tamarisk removal sites across five states in the southwestern United States, we investigated (1) decreases in tamarisk cover; (2) the effects of tamarisk removal on vegetation; and (3) whether cutting or burning tamarisk has differing effects on plant communities. Our study provides an important first step in recognizing the effects of removing a dominant invasive species on meeting long-term goals of riparian restoration. We found that (1) both cutting and burning reduced mean tamarisk foliar cover by 82–95%, and this reduction was sustained over time. (2) Native foliar cover was 2- to 3-fold higher on tamarisk removal sites, but total foliar cover remained 60–75% lower than on control transects. No trend toward increases in native cover was noted over time. When tamarisk was included in the analyses, diversity in tamarisk removal sites was 2- to 3-fold higher than in the control sites and vegetation communities differed between treated and untreated sites. When tamarisk was excluded from the analyses, diversity was not greater at tamarisk removal sites, and there were no community differences between the treated and untreated transects. Differences in diversity were found to be driven by differences in evenness; overall species richness did not change following tamarisk removal. Sites in the Mojave showed the strongest increase in native foliar cover and diversity, Chihuahuan-transition sites showed a slight increase, and sites on the Colorado Plateau showed no overall increase. (3) There were no differences between plant communities at burned and cut sites. Our research indicates that vegetation response to tamarisk removal is often negligible. Land managers should be prepared for persistent depauperate plant communities following tamarisk removal if additional restoration measures are not instigated.     

基于层次分析法的江苏宁镇山脉乡土树种评价

为了筛选适宜南京地区的优良城市绿化树种,在野外调查和问卷调查的基础上,利用层次分析法(AHP)建立江苏宁镇山脉乡土树种评价体系,对该区域的乡土树种进行客观的定量分析。结果表明:(1)乡土树种作为城市绿化树种应首先考虑抗逆性,其次是生态价值、美学价值和生物学特性;(2)参与评价的41种宁镇山脉乡土树种可分为4类,其中I类乡土树种应大力推广应用,Ⅱ类乡土树种可作为森林城市树种多样性的有益补充,Ⅲ类和Ⅳ类乡土树种作为城市绿化树种仍有一定的差距。13种Ⅰ类乡土树种作为城市绿化树种具有良好的应用前景。     

Plant invasions,restoration, and economics: Perspectives from South African fynbos

Restoration is gaining importance in the management of plant invasions. As the success of restoration projects is frequently determined by factors other than ecological ones, we explored the ecological and financial feasibility of active restoration on three different invaded sites in South Africa's Cape Floristic Region. The aim of our study was to identify cost-effective ways of restoring functional native ecosystems following invasion by alien plants. Over three years we evaluated different restoration approaches using field trials and experimental manipulations (i.e. mechanical clearing, burning, different soil restoration techniques and sowing of native species) to reduce elevated soil nutrient levels and to re-establish native fynbos communities. Furthermore we investigated the possibility of introducing native fynbos species that can be used for sustainable harvesting to create an incentive for restoration on private land.Diversity and evenness of native plant species increased significantly after restoration at all three sites, whereas cover of alien plants decreased significantly, confirming that active restoration was successful. However, sowing of native fynbos species had no significant effect on native cover, species richness, diversity or evenness in the Acacia thicket and Kikuyu field, implying that the ecosystem was sufficiently resilient to allow autogenic recovery following clearing and burning of the invasive species. Soil restoration treatments resulted in an increase of available nitrogen in the Acacia thicket, but had no significant effects in the Eucalyptus plantation. However, despite elevated available soil nitrogen levels, native species germinated irrespective whether sown or unsown (i.e. regeneration from the soil seed bank).Without active introduction of native species, native grasses, forbs and other shrubs would have dominated, and proteoids and ericoids (the major fynbos growth forms) would have been under-represented.The financial analysis shows that income from flower harvesting following active restoration consistently outweighs income following passive restoration, but that the associated increase in income does not always justify the higher costs. We conclude that active restoration can be effective and financially feasible when compared to passive restoration, depending on the density of invasion. Active restoration of densely invaded sites may therefore only be justifiable if the target area is in a region of high conservation priority.     

Decline in local ecological knowledge in the Colombian Andes may constrain silvopastoral tree diversity

Local ecological knowledge (LEK) can play an important role in ecological restoration by guiding landholder decision‐making towards more ecologically oriented land management. Silvopastures are a promising option for restoring ecological function to degraded landscapes because they increase tree cover and diversity, moderating the impacts of cattle production on ecological processes. Some silvopastoralists possess considerable LEK that can shape silvopastoral tree communities, but little is known about the temporal trends of this knowledge base. We followed up on a survey of workers, managers, and owners of silvopastoral farms in the Colombian Andes 6 years later and found that the ability to identify native trees and describe their uses, and interest in tree planting, were significantly lower. Importantly, the likelihood that an individual would plant a species was linked directly to the number of uses they listed for that species. Furthermore, the utility of species became more important for influencing the probability of planting native trees over time, as general interest in planting trees declined. We show that knowledge about the uses of native trees is critical for promoting cultivation of diverse tree species in silvopastoral systems, and that multipurpose trees are most likely to be planted. Moreover, our results suggest that the socio‐economic changes driving declines in ecological knowledge elsewhere, including outmigration and limited transmission of knowledge to younger generations, appear to erode LEK among Colombian silvopastoralists. Preserving LEK is therefore a critical factor for ensuring silvopastoral and other agro‐ecosystems can contribute to efforts to restore ecological integrity to degraded landscapes.