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1.
Aim To quantify the interaction between climate and woodland continuity in determining the bioclimatic response of lichen epiphytes. Location Northern Britain (Scotland). Methods Indicator‐species analysis was used to pre‐select lichen epiphytes along parallel gradients in climate and the extent of old‐growth woodland. Nonparametric multiplicative regression was used to describe in a predictive model the individualistic response of selected species, which were projected based on climate‐change scenarios and contrasting patterns of simulated woodland loss or gain. Species with a similar response were grouped using a novel application of cluster analysis to summarize the potentially huge number of projected outcomes. Projected patterns of occurrence under climate‐change scenarios were examined for different levels of old‐growth woodland extent. Results Forty‐two lichen species were statistically significant indicator species in oceanic woodlands, and old‐growth indicators under suboptimal climatic conditions. Responses to climate‐change scenarios were contrasting, with one group comprising species projected to increase in extent in response to climate warming, and other response groups projected to decrease in occurrence, possibly in response to shifting rainfall patterns. The occurrence of all response groups had a positive relationship with old‐growth woodland extent. Main conclusions An ‘oceanic’ biogeographical group of epiphytes identified using the baseline climatic and present‐day woodland setting comprised species with a cyanobacterial photobiont or tropical phytogeographical affinities. However, within this group the individual species responses to climate‐change scenarios were contrasting. Additionally, group responses may be poorly matched with simple ecological traits. However, the studied interaction between climate and habitat continuity suggests that the impact of climate change might be offset for certain lichen epiphytes by appropriate management of woodland resources, for example, expansion of native woodland around remnant old‐growth stands. 相似文献
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Lichens show that fungi can acclimate their respiration to seasonal changes in temperature 总被引：5，自引：0，他引：5
Five species of lichens, the majority members of a soil-crust community (Cladonia convoluta, Diploschistes muscorum, Fulgensia fulgens, Lecanora muralis, Squamarina lentigera) showed seasonal changes of temperature sensitivity of their dark respiration (DR) to such an extent that several substantially met the definition of full acclimation, i.e. near identical DR under different nocturnal temperature conditions during the course of the year. C. convoluta, for example, had maximal DR at 5°C of –0.42, –1.11 and –0.09 nmol CO2 g–1 s–1 in autumn, winter, and summer, respectively, a tenfold range. However, at the mean night temperatures for the same three seasons, 9.7°C, 4.2°C and 13.6°C, maximal DR were almost identical at –1.11, –0.93, and –1.45 nmol CO2 g–1 s–1. The information was extracted from measurements using automatic cuvettes that continuously recorded a sample lichens gas exchange every 30 min under near-natural conditions. The longest period (for L. muralis) covered 15 months and 22,000 data sets whilst, for the other species studied, data blocks were available throughout the calendar year. The acclimation of DR means that maximal net carbon fixation rates remain substantially similar throughout the year and are not depressed by increased carbon loss by respiration in warmer seasons. This is especially important for lichens because of their normally high rate of DR compared to net photosynthesis. We suggest that lichens, especially soil-crust species, could be a suitable model for fungi generally, a group of organisms for which little is known about temperature acclimation because of the great difficulty in separating the organism from its growth medium. Fungi, whether saprophytic, symbiotic or parasitic, including soil lichens, are important components of soil ecosystems and contribute much of the respired CO2 from these systems. Temperature acclimation by fungi would mean that expected increases in carbon losses caused by global climate warming from soil ecosystems might not be as extensive as first thought. This would ameliorate this positive feedback loop present in some climate models and might substantially lower the predicted warming.This work is dedicated to Professor Hubert Ziegler on the occasion of his 80th birthday. We would like to acknowledge his impressive contribution to physiological plant ecology, and to wish him continuing joie de vivre with his scientific interests during a happy retirement. 相似文献
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Axioms developed from island biogeography theory (i.e. species–area relationships, effects of fragmentation and isolation) are central to the development of conservation strategy. Within this context, the 'extinction debt' hypothesis brings into question an often assumed relationship between species richness and present-day spatial habitat structure (i.e. extent, fragmentation), suggesting instead that the richness and composition of biological communities may lag behind spatial changes in habitat. We examined evidence for an extinction debt among epiphytic lichens, a highly diverse biological group of significant conservation concern. Using sites in Scotland, we compared epiphyte species richness in smaller-scale habitat units (aspen stands) to larger-scale woodland structure (extent and fragmentation) measured at two spatial scales (1 km2 and 4 km2 ) and for two timeframes, modern (1990s to 2000s) and historic (1860s to 1880s). Species richness was positively related to woodland extent and negatively related to woodland fragmentation; however, richness was explained better by historic woodland structure at a 1-km2 scale, than by modern woodland structure. The results indicate: (1) a coupling of stand-scale epiphyte assembly and dynamics of the wider woodland ecosystem, and (2) a significant lag in the response of epiphyte species richness to habitat spatial structure. However, the effect of spatial habitat structure is different between species groups with contrasting traits. The effect of decreasing woodland extent on epiphyte richness is generally more severe for microlichens (comprising a greater number of rare and specialist species) than the more generalist macrolichens. 相似文献
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全球气候变化不仅给人类社会可持续发展带来严峻挑战,而且严重威胁到生物多样性及生态安全。我国是生物多样性最为丰富的国家之一,气候变化已经在对动物分布、行为和迁移,植物物候、植被和群落结构等方面造成了影响,并增加了珍稀濒危物种的灭绝风险,同时对生态系统的功能方面也造成了明显影响。未来气候变化将成为生物多样性丧失的主要驱动力之一。世界很多国家都在制定生物多样性适应气候变化的策略和采取适应行动,加强生物多样性的保护。本文在分析国外适应策略的基础上,结合中国生物多样性的现状,提出了适应气候变化的策略建议,包括制定生物多样性适应气候变化的国家战略,开展气候变化对生物多样性的影响监测和评估,针对敏感物种的就地保护和迁地保护,针对气候变化将导致退化生态系统开展恢复与重建,重点关注生物多样性适应气候变化优先区的保护,通过科学研究和国际合作,促进生物多样性适应气候变化技术的提高,期望为我国生物多样性保护和应对气候变化提供支持。 相似文献
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All Swedish forest land is at present being surveyed with the aim of mapping woodland key habitats which have an estimated number of ca. 70 000. An untested requirement of these habitats is that they should contain red-listed species. In order to investigate if they fulfill their aim, an inventory of nationally red-listed bryophytes and lichens was performed in ca. 120 randomly selected woodland key habitats distributed throughout the country. The species were recorded in line transects, covering the whole surface of the habitats. The mean number of red-listed species per habitat was 0.7 for bryophytes and 1.4 for lichens with 11 species at the richest site and 71% of the sites having at least one species. Nemoral forests and coniferous forests were the most species-rich habitat types. The habitats of northern Sweden were more species rich than the southern ones. There were weak correlations between presence of bryophytes and lichens. The study shows that a majority of the woodland key habitats contain red-listed bryophyte and lichen species. Further studies are needed in order to record more organism groups and to compare the woodland key habitats with the surrounding matrix forests. 相似文献
6.
《Mammalian Biology》2014,79(1):58-63
The invasive American mink has been a component of Iceland's fauna since the 1930s. Hunting statistics indicate that until 2003 the population size was increasing, but thereafter decreased rapidly. The Icelandic marine environment has experienced various changes in recent years, including rising sea temperature and sand-eel collapse followed by seabird recruitment failure and population declines. Furthermore the arctic fox population has increased at least six-fold in the last three decades. Mink stomach content analysis in the period 2001–2009 revealed diet changes, and signs of reduced prey availability for this generalist predator, that were most significant in males. The most marked shift in composition was a decrease in consumption of birds. Our findings suggest that climate events, together with competition with increasing numbers of arctic foxes over terrestrial food, contributed to the sharp reduction in the mink population from 2004 and onwards. Despite their generalist behaviour, mink have apparently failed to respond fully to these environmental changes, and this susceptibility may benefit attempts to control their numbers. The results are relevant to the ability of top predators in general to cope with diverse ecosystem alterations triggered by climate change. 相似文献
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The climate change risk to biodiversity operates alongside a range of anthropogenic pressures. These include habitat loss and fragmentation, which may prevent species from migrating between isolated habitat patches in order to track their suitable climate space. Predictive modelling has advanced in scope and complexity to integrate: (i) projected shifts in climate suitability, with (ii) spatial patterns of landscape habitat quality and rates of dispersal. This improved ecological realism is suited to data-rich model species, though its broader generalisation comes with accumulated uncertainties, e.g. incomplete knowledge of species response to variable habitat quality, parameterisation of dispersal kernels etc. This study adopts ancient woodland indicator species (lichen epiphytes) as a guild that couples relative simplicity with biological rigour. Subjectively-assigned indicator species were statistically tested against a binary habitat map of woodlands of known continuity (>250 yr), and bioclimatic models were used to demonstrate trends in their increased/decreased environmental suitability under conditions of ‘no dispersal’. Given the expectation of rapid climate change on ecological time-scales, no dispersal for ancient woodland indicators becomes a plausible assumption. The risk to ancient woodland indicators is spatially structured (greater in a relative continental compared to an oceanic climatic zone), though regional differences are weakened by significant variation (within regions) in woodland extent. As a corollary, ancient woodland indicators that are sensitive to projected climate change scenarios may be excellent targets for monitoring climate change impacts for biodiversity at a site-scale, including the outcome of strategic habitat management (climate change adaptation) designed to offset risk for dispersal-limited species. 相似文献
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Aim The coastal temperate rain forests of north‐western North America are internationally renowned as the archetypal expression of the temperate rain forest biome. Less well documented is the existence of somewhat similar forests 500–700 km inland on the windward slopes of the Columbia and Rocky Mountains. Here we attempt to show that these inland ‘wetbelt’ forests warrant rain forest status. Location North‐western North America. Methods We use tree‐dwelling macrolichens to assess the degree of environmental congruence between the coastal temperate rain forests and their inland counterparts. Results We report three key findings: (1) 40% of oceanic, epiphytic macrolichens found in Pacific coastal rain forests occur also in inland regions; (2) epiphytic species richness decreases with decreasing latitude, such that roughly 70% of disjunct oceanic species are restricted to regions north of 51° N; and (3) the southward decline in lichen diversity is correlated with a parallel decrease in summer precipitation, but not with mean annual precipitation. Main conclusions These observations are consistent with the recognition of an inland rain forest formation between 50 and 54° N. Inland rain forests represent a small, biologically significant ecosystem whose continued fragmentation and conversion to tree plantations warrant close scrutiny. 相似文献
9.
ELISABETH C. CHARMAN KEN W. SMITH DEREK J. GRUAR STEPHEN DODD PHILIP V. GRICE 《Ibis》2010,152(3):543-555
Lesser Spotted Woodpecker Dendrocopos minor numbers have declined greatly in England since the early 1980s for reasons that are not yet fully understood. It has been suggested that the species’ decline may be linked to the increase in Great Spotted Woodpeckers Dendrocopos major, changes in woodland habitat quality (such as deadwood abundance) and landscape‐scale changes in tree abundance. We tested some of these hypotheses by comparing the characteristics of woods in southern England where the species is still relatively numerous with those of woods used in the 1980s before the major decline. In each time period, habitat, predator and landscape information from woods known to be occupied by Lesser Spotted Woodpeckers was compared with those found to be unoccupied during surveys. Before the main period of decline, Lesser Spotted Woodpeckers used oak‐dominated, mature, open woods with a large amount of standing deadwood. Habitat use assessed from recent data was very similar, the species being present in mature, open, oak‐dominated woodlands. There was a strong relationship between wood use probability and the extent of woodland within a 3‐km radius, suggesting selection for more heavily wooded landscapes. In recent surveys, there was no difference in deadwood abundance or potential predator densities between occupied and unoccupied woods. Habitat management should focus on creating and maintaining networks of connected woodlands in areas of mature, open woods. Finer‐scale habitat selection by Lesser Spotted Woodpecker within woodlands should be assessed to aid development of beneficial management actions. 相似文献
10.
《Fungal Ecology》2019
Fungi historically placed in the iconic genera of Boletus, Leccinum and Xerocomus have been the subject of major taxonomic revisions in recent years. Yet, despite all advancements in systematics, boletoid fungi in insular ecosystems remain little explored and our knowledge of their diversity, distribution and abundance in Mediterranean ecoregions is far from complete. To shed light on this blind spot, the findings of a ten-year study from the island of Cyprus were analysed, integrating phylogenetic, ecological, morphological, phenological and chorological data. An unexpected diversity of Boletaceae fungi is unveiled, with twenty-five species phylogenetically confirmed to be present on the island, thirteen of them previously unreported. Sequencing of the ITS rDNA region, reveals crypticism within the Butyriboletus fechtneri, Caloboletus radicans, Rubroboletus lupinus and Rheubarbariboletus armeniacus species-complexes and infrageneric relationships are discussed. A strong link between boletoid fungi and Mediterranean oaks of the ilicoid group (Quercus alnifolia, Quercus coccifera subsp. calliprinos) is illustrated, with nineteen species (76%) overall found to be strictly or broadly associated with evergreen oaks. In stark contrast, the semi-deciduous Quercus infectoria subsp. veneris appears to be an unfavorable host for boletoid fungi, with just a single associated species so far. Phenological and chorological records indicate that most species on the island are rare, highly localized and fruit during very brief spells several years apart, mainly in response to increased annual, late summer or early autumn precipitation. The conservation status of these high-profile fungi is hence discussed, particularly in view of alarming climate changes, forecasted to have a dramatic impact on Mediterranean ecosystems in the years to come. 相似文献
11.
Long‐term stock grazing management in Travelling Stock Reserves and influence on conservation values
We examined the nature of long‐term grazing management implemented in 51 Travelling Stock Reserves (TSRs) in the Albury region, and investigated potential relationships between grazing intensity and conservation values. In general, grazing intensities in most TSRs decreased over the 22 year study period. Most TSRs were lightly grazed (density = 1.1 DSE/ha/year), and stocked for <2 months per year, but some were much more heavily grazed. Spring grazing intensity was found to be negatively associated with TSR conservation values. Our results suggest that grazing management aims to achieve both production and conservation outcomes are not necessarily exclusive to each other. 相似文献
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European National Forest Inventories (NFIs) are well established in most of the European countries. In some NFIs, core samples are taken to estimate volume increments at annual resolution. However, the potential of the NFI for dendroecological investigations has not been evaluated so far. Therefore, the aim of this study was to test the potential of dendrochronological data collected during the Italian NFI in 2006. Silver fir was selected as a test species. Core samples were taken from eighty-one trees including one sample per inventory plot (IP). The 81 IPs were distributed across the Italian Alps and the northern Apennine thus well representing the site conditions of the study area. The effects of the detrending method and sample size on detecting middle- to long-term growth trends and high-frequency climate signals were tested. Further, cluster analysis was applied to find dissimilarities among tree-ring width (TRW) series.Results suggest the detrending method to be the most important factor for detecting growth trends, but not for identification of high-frequency climate signals. Sample size essentially influences the final mean chronology, but it does not bring new information when larger than 30 series. Two groups of trees were recognised with distinct middle-term TRW patterns, although being the same in terms of climate sensitivity. Results are mostly in line with recent findings of other authors, which suggest the potential of the NFI data for dendroecological investigations. 相似文献
14.
Understanding the future impacts of climate and land use change are critical for long-term biodiversity conservation. We developed and compared two indices to assess the vulnerability of stream fish in Missouri, USA based on species environmental tolerances, rarity, range size, dispersal ability and on the average connectivity of the streams occupied by each species. These two indices differed in how environmental tolerance was classified (i.e., vulnerability to habitat alteration, changes in stream temperature, and changes to flow regimes). Environmental tolerance was classified based on measured species responses to habitat alteration, and extremes in stream temperatures and flow conditions for one index, while environmental tolerance for the second index was based on species’ traits. The indices were compared to determine if vulnerability scores differed by index or state listing status. We also evaluated the spatial distribution of species classified as vulnerable to habitat alteration, changes in stream temperature, and change in flow regimes. Vulnerability scores were calculated for all 133 species with the trait association index, while only 101 species were evaluated using the species response index, because 32 species lacked data to analyze for a response. Scores from the trait association index were greater than the species response index. This is likely due to the species response index's inability to evaluate many rare species, which generally had high vulnerability scores for the trait association index. The indices were consistent in classifying vulnerability to habitat alteration, but varied in their classification of vulnerability due to increases in stream temperature and alterations to flow regimes, likely because extremes in current climate may not fully capture future conditions and their influence on stream fish communities. Both indices showed higher mean vulnerability scores for listed species than unlisted species, which provided a coarse measure of validation. Our indices classified species identified as being in need of conservation by the state of Missouri as highly vulnerable. The distribution of vulnerable species in Missouri showed consistent patterns between indices, with the more forest-dominated, groundwater fed streams in the Ozark subregion generally having higher numbers and proportions of vulnerable species per site than subregions that were agriculturally dominated with more overland flow. These results suggest that both indices will identify similar habitats as conservation action targets despite discrepancies in the classification of vulnerable species. Our vulnerability assessment provides a framework that can be refined and used in other regions. 相似文献
15.
以中国科学院武汉植物园内栽培的长果秤锤树(Sinojackia dolichocarpa C. J. Qi)、山白树(Sinowilsonia henryi Hemsl.)、夏腊梅(Sinocalycanthus chinensis Cheng et S. Y. Chang)、紫茎(Stewartia sinensis Rehd. et Wils.)和绒毛皂荚(Gleditsia vestita Chun et How ex B. G. Li) 5种迁地保育植物为对象,通过2008-2016年观察记录的初花期物候及整个花期长度的数据,研究花期的年际变化规律及其与迁入地武汉气候因子的相关性。结果显示:(1)从初花期来看,长果秤锤树的初花期每年提前1.25 d,紫茎的初花期每年推迟1.35 d,绒毛皂荚的初花期每年推迟1.22 d。(2)从花期长度来看,山白树的花期每年增加1.72 d,夏蜡梅的花期每年减少1.62 d,紫茎的花期每年增加0.32 d。(3)从花期与气候因子的相关性来看,年降水量、年平均相对湿度、 10℃有效积温、花前 10℃的有效积温是影响这5种植物初花期、花期长度的主要气候因子;不同物种间影响花期的主要气候因子有所差异。 相似文献
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Aapa mires are EU priority habitats that harbour unique biodiversity values but face increasing global change threats. Here, we investigate the exposure of red-listed aapa mire species inhabiting fen and flark fen habitats to the impacts of land use and climate change. Climate change-based threats were assessed across the aapa mire zone of Finland based on climate velocities (a metric describing the speed and direction of climate movement) measured for mean January temperature (TJan), growing degree days (GDD5) and mean annual water balance (WAB). Land use threats were assessed based on the cover of drainage ditches and three other adverse land use types around the species occurrences. Our results suggest that rapid changes in TJan may alter winter thermal conditions and thereby also species performance, particularly in the northernmost part of the aapa mire zone, where the most valuable concentrations of red-listed species are situated. The land use and GDD5 threats are highest in the southern regions where the red-listed aapa mire species occurrences are sparser but face severe risks to their persistence. In the central part of the aapa mire zone, a number of valuable aapa mires with red-listed species are exposed to both intermediately high TJan and GDD5 velocities and a spatially varying amount of ditching. Three conservation approaches to support the persistence of red-listed aapa mire species: (i) restoration, (ii) establishment of new protected areas, and (iii) monitoring of the key habitats, should be flexibly and complementarily applied to the preservation of aapa mires subject to accelerating climate change. 相似文献
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- By the year 2100, temperatures are predicted to increase by about 6 °C at higher latitudes and about 3 °C in the tropics. In spite of the smaller increase in the tropics, consequences may be more severe because the climatic niches of tropical species are generally assumed to be rather narrow due to a high degree of climate stability and higher niche specialisation. However, rigorous data to back up this notion are rare.
- We chose the megadiverse genus Anthurium (Araceae) for study. Considering that the regeneration niche of a species is crucial for overall niche breadth, we focused on the response of germination and early growth through a temperature range of 24 °C of 15 Anthurium species, and compared the thermal niche breadth (TNB) with the temperature conditions in their current range, modelled from occurrence records.
- Surprisingly, an increase of 3 °C would lead to a larger overlap of TNB of germination and modelled in situ temperature conditions, while the overlap of TNB of growth with in situ conditions under current and future conditions is statistically indistinguishable.
- We conclude that future temperatures tend to be closer to the thermal optima of most species. Whether this really leads to an increase in performance depends on other abiotic and biotic factors, most prominently potentially changing precipitation patterns.