Changes in the flora of Thoreau’s Concord

To determine the effectiveness of conservation efforts, scientists and land managers must evaluate the ability of conservation areas to protect biological diversity. The historic town of Concord, Massachusetts, home of the philosopher and naturalist Henry David Thoreau, provides a unique opportunity to examine how well conservation areas preserve biodiversity in a suburban landscape. About 35% of total land area in the town has been protected, and botanists, including Thoreau, have surveyed plants in Concord five times over the last 170 years. We spent 5 years (2003-2007) re-surveying a subset of Concord’s flora for species presence and abundance. Of the species seen by Thoreau in the mid-19th century in Concord, we could not locate 27%, and an additional 36% persist in one or two populations where they are vulnerable to local extinction. Most species losses appear to have occurred in the past three to four decades. Certain groups, such as orchids, have shown particularly severe losses. More native species are declining in abundance than are increasing. Non-native species represent an increasing percentage of the flora, with many increasing in abundance. The flora has experienced a net loss of species over the past four decades, with 82 species gained and 236 species missing. Because many species are rare on a local scale, persisting as one or two small populations, local extinctions will likely continue in coming decades. Habitat management, primarily to prevent tree establishment, appears to have allowed many rare species of open habitats to persist and recover. Active management of existing sites will likely be the key to protecting the species diversity of the Concord flora and maintaining the living connection to the writings of Thoreau.     

To what extent are threatened European plant species conserved in seed banks?

The number of ex situ conservation facilities has grown dramatically in recent years, and they have become increasingly integrated under national and regional conservation initiatives. However, little information is available about the extent to which plant species are appropriately represented in ex situ collections. This paper assesses whether seed/spore collections stored in European seed banks cover or not, and to what extent, the species currently threatened with extinction in the wild. Although a substantial amount of the European flora (ca. 70%) is currently stored in seed banks, we highlight the relatively poor representation of threatened species: only 27% of the taxa listed on the European threatened plant list and 44% of the taxa listed in Annex II of the EU Habitat Directive are stored in European seed banks. Some taxonomical groups most at risk, e.g. Pteridophytes and Orchidaceae, are also under-represented in European seed banks. By examining the number of accessions per species and the number of seeds per accession, this study also gave some insight on how well species are conserved, considering that these two variables are surrogates for genetic diversity. We have highlighted that at least two thirds of the threatened species stored in European seed banks likely suffer from too low genetic diversity in the collections. These analyses were essential to identify those collections and additionally the standards needed to maximize the usefulness of future collections.     

Effects of community-level grassland management on the non-target rare annual Agalinis auriculata

The objective of grassland management is to maintain keystone species, as well as species diversity, to promote a particular community structure, or to preserve specific ecosystem processes. Studies of grassland management rarely ascertain the effects on rare plant species, although conservation plans for rare herbaceous plants often recommend habitat management as well as restoration activities. Indeed, conservation biology has evolved from a relatively species-specific discipline into one more focused on larger scale issues such as ecosystem function, community composition and habitat restoration. Few studies have tested whether species of concern are adequately managed with a community or ecosystem-level approach. In this study, we evaluate whether community-level management of white-tailed deer and woody brush improves the viability of the rare annual plant species, Agalinis auriculata (Earleaf false foxglove; Orobanchaceae). Reducing deer browse and removing brush each positively affect plant vital rates. Brush removal increases the proportion of plants that reach the largest size class. Reducing deer browse increases the fertility of plants, particularly those in the largest size class. We report on demographic matrix models created with data from five populations of A. auriculata studied across 4 years. We find that both management activities positively affect the non-target plant species and are, in fact, necessary for A. auriculata to persist. Conservation of A. auriculata at our study sites requires both reducing the density of white-tailed deer and brush removal. Our study demonstrates that management at the community and ecosystem levels can be compatible with conservation goals at the species and population levels.     

The effect of different fire regimes on plant diversity in southern African grasslands

South African grasslands support a rich flora that is attracting growing conservation interest. Fire has long been used to manage grasslands for livestock production. However, there is very little information on the effects of fire on forb diversity to help guide conservation management. We studied plant diversity at scales of 1 and 100 m² in three long-term burning experiments in mesic, montane and semi-arid grasslands, respectively, to explore forb responses to different fire regimes. Though the dominant grasses were strongly influenced by season and frequency of fire, forb diversity showed no consistent trends. Ordination results showed that forb composition varied less with fire treatment than with local site conditions. Forbs in all three grasslands seem remarkably resilient to fire. However, all three sites showed large compositional changes if fires were excluded for about 10 or more years, with the replacement of many species by a suite of, mostly, woody species. Patterns of beta-diversity sampled in the montane grassland, showed somewhat different patterns, with species turnover increasing with inter-fire interval. Our results indicate that most forb species tolerate a wider range of season and frequency of fires than the dominant grasses. However, to accommodate those species with low tolerance of frequent fires, parts of the landscape will require less frequent fires.     

The influence of plant diversity on people’s perception and aesthetic appreciation of grassland vegetation

The conservation of biodiversity critically depends on the value that humans attach to it. Apart from an ecological and economic value, an aesthetic value has often been assigned to biodiversity. However, it is not known whether lay people appreciate the diversity of species and not just certain individual species or nature as a whole. We studied in a series of experiments and field studies people’s perception and appreciation of species diversity. We presented meadow-like arrays of different species richness and evenness but random species composition to lay people and asked them to estimate plant species richness and rank the arrays by attractiveness. The experiments were complemented by two larger-scale field studies using natural meadows. Both in the experiments and the field studies the mean perception of species richness by people increased with true species richness, but was slightly overestimated at low and increasingly underestimated at high diversity levels. Lay people’s aesthetic appreciation of both the experimental grassland arrays and the natural meadows increased with true species richness. Communities consisting of the same number of species were perceived to be more species-rich and were appreciated more when their evenness was high. Our results demonstrate that plant diversity in itself is attractive to humans. The current reduction of the diversity of grasslands due to intensification of management may thus reduce the attractiveness of regions where grasslands are a dominant feature of the landscape. This could have negative consequences for tourism and may add an economic argument for the conservation of biodiversity in grasslands.     

The role of buried seed in coppicewoods

The ancient coppicewoods of eastern England have high conservation value when managed as such, but neglect leads to loss of species from the vegetation. The present paper reports a study of the potential for vegetational recovery which is conferred by the presence of dormant buried seeds in neglected coppices. These seed-banks are discussed both in relation to the pattern of floristic change in the coppice cycle, and to the conservation of the coppicewood flora.It is shown that many of the coppicewood plants are present as buried seed though absent from the vegetation, especially the light-demanding ‘marginal’ species which normally reappear after each coppicing in the managed system.Very few species of the deep shade are present as seed, however, and because such species also tend to have poor dispersive powers, it is suggested that they are more vulnerable than the marginal flora to any extreme management changes which might lead to their complete disappearance from the vegetation.     

Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors

Decline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity.     

National inventories of crop wild relatives and wild harvested plants: case-study for Portugal

Crop wild relatives (CWR) and wild harvested plant species (WHP) constitute an important element of a nation’s plant genetic resources (PGR) available for utilisation. Although their natural populations are threatened like other wild species by habitat lost and fragmentation, little attention has generally been paid to their systematic conservation. The development of checklists and inventories is considered by the convention on biological diversity (CBD) and the global strategy for plant conservation (GSPC) as the first step in any national strategy for conservation and sustainable use of plant diversity. Methodological approaches to the development of a national inventory of wild PGR are discussed in the light of a case-study for the CWR and WHP growing in mainland Portugal. The resultant inventory comprises 2319 taxa, of which 97.5% are CWR, 21.4% are WHP and 19.0% are both CWR and WHP. Approximately 6.1% are endemic to mainland Portugal; 24.1% occur in 1 to 4 Portuguese administrative regions; 15.6% are threatened, but only 5.9% are covered by legislative protection. Taxonomic misalignments and the dispersed nature of biological literature were the major impediments to the production of the national inventory, but once the inventory was established it has proven to be a powerful tool in conservation management.     

黄前水库集水区典型人工林群落物种多样性

 为给黄前流域人工林综合治理的进一步实施提供科学依据,对流域内4种人工林群落的植物区系组成和地理成分进行分析,并采用常规生物多样性的调查方法对其物种多样性特征进行了定量研究。结果表明:1)该流域的植物区系比较丰富,占泰山植物区系物种总数的13.02%;2)4种人工林灌木层和草本层的Simpson指数、Shannon-Wienner指数和均匀度指数差异显著,物种丰富度指数差异不显著,草本层发育明显好于灌木层;3)各人工林尚处于演替初期阶段,混交林下多以阴生性植物为主,其他林下植被发育常以禾本科等阳生性植物为主;4)不同人工林物种总体多样性特征分析表明,板栗林总体物种丰富度最低,均匀度指数最大,多样性指数较低,而赤松+元宝槭混交林总体物种丰富度最大,多样性指数也最大,均匀度指数较低,群落总体多样性混交人工林较大而单一林分较小,混交人工林更有利于林下植被的发育和更新。     

A checklist of the cultivated plants of Ustica (Italy)

The small island of Ustica north of Sicily has been investigated for its plant genetic resources in 1997. A checklist of the agri- and horticultural crop plants comprises more than 110 species. Some of the species show still a large infraspecific variation but genetic erosion could be also found. Rare material has been collected for the conservation in genebanks.The considerable agrobiodiversity and the ongoing evolution as evidenced by introgression from wild relatives to several cultivated species and vice versa suggest the development of an on-farm conservation for the island. Nature protection and traditional farm management should develop an integrated approach.     

Evaluating patterns of biodiversity in managed grasslands using spatial turnover metrics

Market and policy incentives that encourage agricultural intensification, such as incentives for bioenergy, may contribute to biodiversity decline when they encourage a large-scale conversion of native and semi-natural ecosystems to production fields. In order to appreciate the impact of these incentives on biodiversity, it is imperative to better understand how native and semi-natural ecosystems contribute to plant diversity and composition. We studied the five most common types of managed grasslands in Northeastern Kansas, a region undergoing agricultural intensification. We analyzed plant community data recorded at three spatial scales in 98 managed grassland sites, and examined patterns of diversity and composition of plant species and functional groups; and spatial turnover of species and functional groups measured at different spatial scales. We found reduced soil quality and plant diversity as well as a lack of scale-dependent community patterns on sites that were historically cultivated. Forage management practices (haying or grazing) altered plant diversity and composition in native grassland remnants but not in non-native grasslands. We identified several opportunities where changes to existing management practices could benefit both conservation and bioenergy production objectives. Recommendations to conserve biodiversity include increasing the use of hay management or other biomass collection on native grassland remnants and improving the Conservation Reserve Program by increasing enrollment, adding more native species to seed mixes, and incorporating a periodic biomass collection. We also found that using measures of spatial turnover in community composition added important insights in understanding the effects of management decisions on biodiversity.     

Conserving the genetic resources of crop wild relatives in European Protected Areas

European native plant diversity is currently suffering erosion and extinction and thus, it is crucial to improve conservation strategies to maintain this essential resource. If unchecked, this genetic erosion and species extinction will cause unnecessary and irreversible harm to the economy and social well being of Europe. Much plant biodiversity is undoubtedly found in the existing 9654 European protected areas that cover 1,066,358 km², but clearly targeted and active conservation of priority plant species is required within these protected areas. To help ensure more efficient long-term sustainable conservation, a novel approach to the in situ conservation of European plants, notably crop wild relatives, is suggested. The purpose of this approach is to know what plant genetic resources (PGR) we have, where they are located and to assess whether the current network of protected areas includes a representative sample of European PGR diversity. The generation of in situ conservation and management plans for PGR populations in existing protected areas can significantly improve the present conservation status. Additionally, the identification of gaps of certain PGR in current protected areas can provide the basis for the designation of new complementary PGR in situ reserves.     

Fertilizer application during primary succession changes the structure of plant and herbivore communities

Fertilization of secondary successional communities generally increases biomass but reduces diversity; its impact on primary successional communities is less well understood. Following applications of a balanced fertilizer to naturally established vegetation on slate quarry waste, effects on tree growth, ground flora species and foliar invertebrates were monitored over two years. Fertilization increased tree growth, with stem basal area increasing by 130% over two growing seasons compared with a 50% increase in unfertilized trees. Several dominant ground flora species increased in cover as a result of fertilization. In contrast, cover of bryophytes was not increased. Fertilization favoured plant species associated with drier habitats, but disadvantaged less-competitive ruderal species. Tree foliar invertebrates were less abundant on the trees on slate waste than on trees in established woodland. Fertilization made tree leaves more palatable by increasing nitrogen and reducing soluble polyphenol concentrations, and increased the abundance of sap-sucking invertebrates, without changing foliar invertebrate diversity. Overall, fertilizing this primary successional site was beneficial for biodiversity; it increased abundance of dominant plant species and foliar invertebrate herbivores, yet few taxa were adversely affected during this period. Increases in tree biomass and invertebrate abundance are likely to favour the establishment of other taxa. Where the biodiversity conservation interest is principally in closed-canopy vegetation, applying fertilizer is a cheap, comparatively non-intrusive and effective way to increase biodiversity on denuded sites. However, plant species characteristic of open and infertile habitats (particularly bryophytes) and their obligate herbivorous invertebrates are likely to decrease in abundance.     

Influence of management regimes of adjacent land uses on the woody plant richness of hedgerows in Spanish cultural landscapes

Hedgerows are an important component of the cultural landscape and may have an invaluable role in maintaining biological diversity. Adjacent land use potentially has an important influence on the species composition of hedgerows. In the Mediterranean region, hedgerows are considered as remnants of past practices and their function may be linked with the prevailing agrarian systems, in turn related to societal change. In this paper, the characteristics of hedgerows in Central Spain, and their interactions with adjacent fields were studied in order to understand their contribution to maintaining woody plant species richness in the cultural landscape. The hedgerow typology of the region were found to respond jointly both to environmental and livestock farming-related variations in adjacent land uses. The variation in the management intensity of the landscape is reflected in the composition of the woody plant species of hedgerows, varying from species of open landscape to woodland species. Moderate degrees of grazing allow for higher values of woody plant richness in hedgerows compared with those hedgerows separating systems subjected to a higher livestock loads or to abandonment processes. Thus, hedgerows potentially contribute to the functionality of these cultural landscapes and provide a basis of important ecological and historical value in landscape conservation planning. These conclusions have important implications in the development of landscape conservation and protection policies.     

Magnitude of Species Diversity Effect on Aboveground Plant Biomass Increases Through Successional Time of Abandoned Farmlands on the Eastern Tibetan Plateau of China

Recent empirical and theoretical studies have shown that magnitude and direction of biodiversity effects on ecosystem functioning can shifts over time. Here, we used species richness and plant abundance (total individual plant stem density) as proxies for species diversity and aboveground biomass for productivity. We used an analytical approach combining both chronosequence and 6 year of vegetation monitoring in a subalpine ecosystem as a model system to assess temporal species richness–abundance–aboveground biomass relationships at different successional stages and spatial scales. We observed that both species richness and plant aboveground biomass increased rapidly early in succession after land abandonment, then after 10 years of abandonment reached a steady state. We found that the relationship between species richness and plant abundance with aboveground biomass was strengthening over successional time. In all successional stages, species richness had stronger positive effects as compared with plant abundance on plant aboveground biomass. Species richness was linearly correlated with aboveground biomass, whereas plant abundance showed a humped‐back relationship with aboveground biomass across all successional stages. Our results showed an increase in the effect of plant diversity over time, and a combination of both plant species richness and abundance is correlated with plant productivity throughout successional time, knowledge that maybe important to managing ecological restoration and conservation. Copyright © 2016 John Wiley & Sons, Ltd.     

Grazing management of calcareous grasslands and its implications for the conservation of beetle communities

Calcareous grasslands are an important habitat for floral and faunal communities in the UK and Europe. Declines due to changes in management, scrub invasion and agricultural improvement have left much of the remnants of this habitat in a degraded and fragmented state. Grazing, by cattle or sheep, is one of the main management practices used to maintain and improve the floral and faunal quality of calcareous grassland. The long-term impacts of different grazing regimes, however, are poorly understood, particularly in terms of the invertebrate communities. This study contrasted the impacts of recently introduced and long-term sheep or cattle grazing on beetle communities present on one of the largest areas of calcareous grassland in Europe, the Salisbury Plain military training Area, UK. No effects of grazing management on beetle abundance, species richness or evenness were found, but plant diversity and overall percentage cover of grasses did influence beetle diversity. Proportions of the total number of individuals and overall species richness within beetle guilds (predatory, phytophagous, flower/seed feeders, root feeders and foliage feeders) were strongly influenced by both the duration and type of grazing animal. At the species level, beetle community structure showed significant differences between ungrazed, long-term cattle and long-term sheep grazing treatments. Changes in plant community structure were found to influence beetle community structure. The significance of these results is discussed in terms of the long-term impacts of grazing on beetle community structure, and the benefits of different grazing regimes for the conservation management of calcareous grasslands.     

鲁中水土保持生态修复区种子植物区系特征

 为鲁中石质山地水土保持生态修复过程中适宜植物种类的选择、保护与合理经营提供理论依据,对淄川峨庄水土保持生态修复区内植物区系组成和地理成分进行分析。结果表明:1)该植物区系内共有种子植物271种,隶属于61科157属,分别占我国种子植物区系科、属、种的17.28%、4.90%和0.998%,其中单种科和极小科（含29种）所含的种数占总种数的91.6%,单种属和含2～4种的属有161个,占总属数的96.18%,可以看出该研究区内植物科和属的分布是比较均匀和丰富的;2)该区植物区系温带成分,特别是北温带成分具有明显优势,热带性质属在该区系中占有较大的比例,说明该地区植物区系与热带植物区系有较密切渊源,并具有一定的亚热带热带区系的过渡性;3)该区植物区系的特有性较低。     

美国市民农园生态植被景观营建及其启示

美国市民农园是一个值得借鉴的兼具生产、生态和生活等多功能的植被景观模式,本研究针对市民农园的生态服务功能,依据市民农园结构模式及经营群体的不同,随机选取了洛杉矶市14个市民农园,采用样地调查、半结构式访谈等方法,基于植被物种功能组合和乡土植物组成,定量化研究了城市植被物种多样性及其分布格局对种植者族裔背景及营建模式等影响因素的响应,进而评析对我国城市绿地建设和休闲农业的启示。本研究共计调查到439种植物,分属90科,242属,分析结果显示:市民农园是城市生态系统中重要的物种库,能维护较为丰富的乡土植物资源;其植物功能以食用植物为主,观赏植物、药用植物次之,这在保护族裔传统文化、区域乡土文化具有重要价值;其植被景观结构和功能受到族裔背景及营建模式等不同程度影响。研究证明,市民农园作为生态多样性和文化多样性的交汇景观,是实现城镇绿色基础建设和休闲农业发展的重要营建模式。以此为经验,我国在进行绿地规划和生态植被建设时要考虑不同利益相关者,尤其是关注外来者的生活习俗和选择偏好;同时也要注意监测外来物种,以防造成物种入侵,这对于建设文化强国背景下开展城镇生态植被建设和发展休闲农业具有启示意义。     

The Dynamics of on-farm Management of Sorghum in Ethiopia: Implication for the Conservation and Improvement of Plant Genetic Resources

On-farm conservation of plant genetic resources for food and agriculture has received strong support worldwide in recent years. It has been justified on appealing assumptions: it complements ex situ conservation, allows co-evolutionary interaction of host–pathogens and crop–weed complexes, and involves local knowledge systems. This article illustrates how on-farm conservation being set for its sake is extremely difficult under farmers’ dynamic management of plant genetic resources based on sorghum. The dynamics of their management could be explained by continued introduction, displacement, loss and maintenance of aboriginal landraces that have distinct functional attributes, patch-occupancy and relative abundance profiles. Such management and hence the dynamic landrace demography has largely been triggered by co-evolving biophysical stresses, spatial and seasonal variations. The best viable alternative to support farmers’ management of genetic resources is to link conservation to crop improvement both to enhance on-farm genetic diversity and make the biophysical environment a comfortable home for the plant genotypes.     

Challenges and opportunities of genetic approaches to biological conservation

I discuss future challenges and opportunities in genetic approaches to biodiversity conservation. Resolving taxonomy uncertainties and identifying diverged evolutionary units within species are both bedevilled by a plethora of definitions: the challenge for the conservation community is to come to an agreed definition of species and for a unit within species for conservation purposes. For genetic management in the wild, the main challenge is to apply well-established genetic principles to management, especially of fragmented populations. Fears about outbreeding depression are preventing rational use of gene flow for genetic rescue; predicting the risk of outbreeding depression is the most important unmet scientific challenge in the field. The major challenge in genetic management of captive populations of threatened animal species is to institute explicit management to minimize genetic adaptation to captivity, so that reintroduction success is maximized. The development of low cost genome sequencing offers many research opportunities and challenges. For example, there are opportunities to identify genes involved in speciation and a major challenge is to devise molecular tests to predict reproductive isolation between populations. Genomics offers opportunities to provide higher precision estimate for many parameters of importance to conservation. A major challenge is to devise means to assess, on a genome-wide basis, genetic diversity that is important to adaptive evolution. There is a challenge to develop simple inexpensive means to monitor genetic diversity of species on a global scale. Many of the most important practical challenges concern application of current genetic knowledge to the management of threatened species.