Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions

Aim We use data from 13 mountain regions and surrounding lowland areas to identify (1) the origins, traits and cultural uses of alien plant species that establish in mountains, (2) the alien species that are most likely to be a threat and (3) how managers might use this information to prevent further invasions. Location Australia, Canada, Chile, India, New Zealand, South Africa, Spain, Switzerland, USA. Methods Lists of alien species were compiled for mountains and their surrounding or nearby lowlands. Principal co‐ordinates analysis was performed on a matrix of similarities created using presence/absence data for alien species. The significance of differences between means for (1) similarity metrics of lowland and mountain groups and (2) species traits of lowland and mountain alien floras was determined using t‐tests. In seven of the 13 mountain regions, lists of alien species undergoing management were compiled. The significance of differences between proportions of traits for species requiring and not requiring management input was determined with chi‐square tests. Results We found that the proximal lowland alien flora is the main determinant of a mountain region’s alien species composition. The highest similarities between mountain floras were in the Americas/Pacific Region. The majority of alien species commonly found in mountains have agricultural origins and are of little concern to land managers. Woody species and those used for ornamental purposes will often pose the greatest threat. Main conclusions Given the documented potential threat of alien species invading mountains, we advise natural resource managers to take preventive measures against the risk of alien plant invasion in mountains. A strategy for prevention should extend to the surrounding lowland areas and in particular regulate the introduction of species that are already of management concern in other mountains as well as climatically pre‐adapted alien mountain plants. These may well become more problematic than the majority of alien plants currently in mountains.     

Flightless insects: a test case for historical relationships of African mountains

Flightless insects give a clearer view of former distribution of montane habitat in Africa compared with highly mobile animals as birds and butterflies because passive long distance transport and long distance dispersal can be discounted. Only a few species in the twenty-one genera under study are shared between neighbouring mountains which can be explained in all cases by a Pleistocene lowering of the montane habitat by 850 m. Therefore a montane forest cover connecting the mountains at colder times as suggested by the pluvial theory can be refuted which is in correspondence with palynological findings suggesting a dry corridor between the mountains. No montane refuge for flightless insects can be identified, because the most species-rich mountain of a genus differs among the genera under study. Instead, each mountain served as a species refuge with a stable habitat. The requirement of a smaller habitat compared to vertebrates is indicated by endemic species on each single mountain suggesting pre-Pleistocene speciation which results even in endemic genera to one mountain. Different small patches of suitable habitat on one mountain could also explain the radiations found in some genera of flightless insects. In some genera species are lacking on Mt Kenya which indicates—with the findings of no endemic passerine bird on the mountain—a probably very dry condition during colder times. On Mt Cameroon no species of the flightless insect genera occurring on the Eastern mountains are found. This contrasts with the existing patterns of birds, grasses and butterflies.     

Diel activity patterns of South Scandinavian high mountain ground beetles (Coleoptera, Carabidae)

Fourteen species of carabids were studied throughout the snowfree season in outdoor arenas above the timberline at Finse, South Norway (60°36'N, 7°30'E). Ten species were nocturnal. Onset of nocturnal activity occurred after termination of twilight with peak activity before midnight, but in June, with less than 1 h of darkness, activity was extended into evening twilight, the peak being around midnight. Linear regressions between ground surface temperature and nocturnal activity predicted zero activity in the range −2.0 to0.8°C, mean −0.5°C, indicating that activity is possible on most nights throughout the snowfree season. Two diurnal species had activity threshold temperatures at 4 and 8°C, respectively, the former with a peak at 16°C and an upper threshold at 28°C.
The proportion of nocturnal species in the study area was significantly greater than in lowland open fields. Large and common species were mainly nocturnal, while small and rare species were mainly diurnal. It is suggested that nocturnalism in the South Scandinavian high mountains is a response to avoid bird predation and desiccation.     

Morphometric analyses of capsule and seed traits in Scandinavian Papaver radicatum (Papaveraceae) in relation to the bicentric distribution pattern

The bicentric distribution pattern of certain plant species in the southern and northern Scandinavian mountains has been explained in different ways. Either by refugial survival, by late-glacial immigration to the first deglaciated areas in southern and northern Norway or by a successive fragmentation of wide-distributed populations during post-glacial time — or by present-day ecological factors. Even if the bicentric distribution pattern is at least partly explained by present-day ecological conditions, the question about the origin of the bicentric distribution still remains. One way to tackle this problem, is to investigate the morphometric and/or the genetic differentiation between isolated populations of ‘bicentric’ species and its impact on the explanation of the disjunct pattern. The overall morphometric differentiation pattern in seeds and capsules was investigated in populations of Papaver radicatum, a perennial herb with a bicentric distribution in the Scandinavian mountain range. Canonical variates analysis of capsules separates the populations into two groups in accordance with their geographic origin, i.e. the regions of southern and northern Scandinavia. The differentiation pattern indicates a two-step development of the present-day distribution: first separation of the southern and northern Scandinavian occurences of older origin, then separation between populations within each region. The results from canonical variates analysis of seeds shows a weaker variation pattern with a tendency of overlapping inter-region populations. The most northerly situated populations from the southern region are grouped with populations from the northern region. The pattern of differentiation in capsules may be interpretated in terms of refugial survival or late-glacial immigration. However, the variation pattern in seeds rather points to a scenario where a widespread occurrence that previously ranged from southern to northern Scandinavia was successively fragmented, which makes a postglacial development of the differentiation pattern more probable.     

Vertebrate range sizes indicate that mountains may be 'higher' in the tropics

In 1967, Daniel Janzen proposed the influential, but largely untested hypothesis, that tropical mountain passes are physiologically higher than temperate mountains. I test his key prediction, the one upon which all the others rely: namely, that elevational range sizes of organisms get larger on mountains at increasing latitudes. My analyses use 170 montane gradients spanning 36.5° S to 48.2° N latitude compiled from over 80 years of research and 16 500 species of rodents, bats, birds, lizards, snakes, salamanders, and frogs. In support of Janzen's prediction, I find that elevational range size increases with increasing latitude for all vertebrate groups except rodents. I document additional lines of evidence for temperature variability as a plausible mechanism for trends in vertebrate range size, including strong effects of thermoregulation and daily temperature variability, and a weak effect of precipitation.     

Diversity and biogeographical makeup of the dung beetle communities inhabiting two mountains in the Mexican Transition Zone

The role of horizontal and vertical colonization on the diversity and integration of the dung beetle fauna of two mountains in the Mexican Transition Zone (Los Tuxtlas and La Chinantla) are analyzed and compared. On each mountain standardized sampling was done using pitfall traps baited with dung and carrion along elevation gradients. On both mountains diversity decreased linearly with increasing elevation. The decrease in the number of genera and species was not different between mountains, but the cumulative total number for both taxonomic levels was significantly higher on La Chinantla. There, three well-defined groups were identified for which species turnover was mainly a result of species gain. On Los Tuxtlas there was no evident grouping pattern, and species turnover was determined by species loss. For both mountains the dominant biogeographic distribution pattern was Neotropical; however, at the higher elevations of La Chinantla, a clear replacement by lineages of Holarctic affinity was observed. We suggest that for La Chinantla—a mountain that is geographically connected to the Sierra Madre Oriental mountain range and is of ancient geological origin—the processes of horizontal and vertical colonization have had relatively different weights in terms of their effect on the pattern of diversity and the biogeographic integration of the beetle community, while on Los Tuxtlas, the limited role of horizontal colonization appears to be a consequence of its isolation and more recent geological origin. We discuss the potential use of these models for studying the effects of climate change on elevation gradients.     

Intraspecific genetic variation in selected mosses of Scandinavian interglacial refugia suggests contrasting distribution history patterns

Three pleurocarpous mosses were studied to explore the haplotype diversity patterns in a Scandinavian system of interglacial refugia in which low‐competitive species of calcareous or base‐rich habitats occur. Hypnum bambergeri and H. vaucheri displayed little variation across Scandinavia. For the third species, Drepanocladus turgescens, an analysis of molecular variance showed that two S Scandinavian lowland regional populations were significantly different from each other and differed or almost differed (Gotland vs. Jämtland, according to pair‐wise Φ_PT) from the populations of the Scandinavian mountain range and Svalbard. Haplotype diversity displayed little variation among regional populations, and did not reflect the higher frequency of sexual reproduction in southern than in mountain populations. A coalescent‐based analysis (LAMARC) indicated immigration into the population now found in the lowlands from that represented in the mountains. This is contrary to that found in Rhytidium rugosum in an earlier study and, together with the fact that sporophytes are produced almost exclusively in the lowlands, speaks against this direction of post‐glacial migration. Therefore, if the LAMARC results reflect migration patterns, these most probably reflect events that occurred earlier. Taken together with the results on R. rugosum, this study emphasizes the fact that moss species having similar distribution patterns reached these distributions in partly different ways. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 295–310.     

Elevational diversity gradients, biogeography and the structure of montane mammal communities in the intermountain region of North America

1  Distribution data were assembled for non-volant small mammals along elevational gradients on mountain ranges in the western U.S.A. Elevational distributions in the species-rich Uinta Mountains were compared to those on smaller mountain ranges with varying degrees of historical isolation from the Uintas.
2  For mountain ranges supporting the richest faunas, species richness is highest over a broad low- to mid-elevation zone and declines at both lower and higher elevations. Patterns on other mountain ranges are similar but reflect lower overall species richness.
3  A basic relationship between elevational and geographical distribution is apparent in the occurrence patterns of mammals on regional mountains. Faunas on mountains that have had low levels of historical isolation appear to be influenced by immigration rather than extinction. Species restricted to high elevations in the Uintas are poorly represented on historically isolated mountains and form a portion of local faunas shaped by extinction. Species occurring at lower elevations in the Uintas have better representation on isolated mountains and apparently maintain populations through immigration.
4  Several widespread species show substantial variation in maximum elevation records on different mountain ranges. This involves (1) an upward shift in habitat zones on small, isolated mountain ranges, allowing greater access by low-elevation species, and (2) expansion of certain low- and mid-elevation species into habitats normally occupied by absent high-elevation taxa.
5  Results indicate that montane mammal faunas of the intermountain region have been shaped by broad-scale historical processes, unique regional geography and local ecological dynamics. Parallel examples among mammals of the Philippine Islands suggest that such patterns may characterize many insular faunas.     

Where do the treeless tundra areas of northern highlands fit in the global biome system: toward an ecologically natural subdivision of the tundra biome

According to some treatises, arctic and alpine sub‐biomes are ecologically similar, whereas others find them highly dissimilar. Most peculiarly, large areas of northern tundra highlands fall outside of the two recent subdivisions of the tundra biome. We seek an ecologically natural resolution to this long‐standing and far‐reaching problem. We studied broad‐scale patterns in climate and vegetation along the gradient from Siberian tundra via northernmost Fennoscandia to the alpine habitats of European middle‐latitude mountains, as well as explored those patterns within Fennoscandian tundra based on climate–vegetation patterns obtained from a fine‐scale vegetation map. Our analyses reveal that ecologically meaningful January–February snow and thermal conditions differ between different types of tundra. High precipitation and mild winter temperatures prevail on middle‐latitude mountains, low precipitation and usually cold winters prevail on high‐latitude tundra, and Scandinavian mountains show intermediate conditions. Similarly, heath‐like plant communities differ clearly between middle latitude mountains (alpine) and high‐latitude tundra vegetation, including its altitudinal extension on Scandinavian mountains. Conversely, high abundance of snowbeds and large differences in the composition of dwarf shrub heaths distinguish the Scandinavian mountain tundra from its counterparts in Russia and the north Fennoscandian inland. The European tundra areas fall into three ecologically rather homogeneous categories: the arctic tundra, the oroarctic tundra of northern heights and mountains, and the genuinely alpine tundra of middle‐latitude mountains. Attempts to divide the tundra into two sub‐biomes have resulted in major discrepancies and confusions, as the oroarctic areas are included in the arctic tundra in some biogeographic maps and in the alpine tundra in others. Our analyses based on climate and vegetation criteria thus seem to resolve the long‐standing biome delimitation problem, help in consistent characterization of research sites, and create a basis for further biogeographic and ecological research in global tundra environments.     

Think globally,measure locally: The MIREN standardized protocol for monitoring plant species distributions along elevation gradients

Climate change and other global change drivers threaten plant diversity in mountains worldwide. A widely documented response to such environmental modifications is for plant species to change their elevational ranges. Range shifts are often idiosyncratic and difficult to generalize, partly due to variation in sampling methods. There is thus a need for a standardized monitoring strategy that can be applied across mountain regions to assess distribution changes and community turnover of native and non‐native plant species over space and time. Here, we present a conceptually intuitive and standardized protocol developed by the Mountain Invasion Research Network (MIREN) to systematically quantify global patterns of native and non‐native species distributions along elevation gradients and shifts arising from interactive effects of climate change and human disturbance. Usually repeated every five years, surveys consist of 20 sample sites located at equal elevation increments along three replicate roads per sampling region. At each site, three plots extend from the side of a mountain road into surrounding natural vegetation. The protocol has been successfully used in 18 regions worldwide from 2007 to present. Analyses of one point in time already generated some salient results, and revealed region‐specific elevational patterns of native plant species richness, but a globally consistent elevational decline in non‐native species richness. Non‐native plants were also more abundant directly adjacent to road edges, suggesting that disturbed roadsides serve as a vector for invasions into mountains. From the upcoming analyses of time series, even more exciting results can be expected, especially about range shifts. Implementing the protocol in more mountain regions globally would help to generate a more complete picture of how global change alters species distributions. This would inform conservation policy in mountain ecosystems, where some conservation policies remain poorly implemented.     

磷的生物有效性对山地生态系统的影响

磷(P)的生物有效性对山地生态系统的发育和稳定至关重要。由于大气CO_2浓度升高和N沉降增加,生态系统C、N和P的化学计量比失衡,P的生物有效性受到更多关注。近年来山地系统中P的研究不断深入,2004—2013年间ISI Web of Knowledge中相关研究论文几乎是此前近百年的3倍。总结了山地生态系统中P的生物有效性的特点及其对植物物种多样性和初级生产力的影响。山地生态系统P的生物有效性因垂直高差和地形梯度空间变异明显,快速物质运移和生物过程是控制山地生态系统P的生物有效性的关键因素。P的生物有效性可以影响山地生态系统物种多样性和初级生产力,其对初级生产力的限制存在于全球范围内的山地生态系统。当P的生物有效性发生改变时,山地生态系统的结构越复杂,其植物物种多样性和初级生产力的响应可能会越平缓。全球变化的重要驱动因子(如增温和N沉降增加)可以直接或间接地改变山地生态系统P的生物有效性,因此需要在山地生态系统中加强长期监测和养分控制实验,并结合新型P分析技术,以期认识山地生态系统P的生物有效性的现状、变化趋势和对生态系统的影响,从而为适应全球变化背景下山地生态系统养分状况的改变提供依据。     

Synchronicity in elevation range shifts among small mammals and vegetation over the last century is stronger for omnivores

In mountain ecosystems, species can be said to respond synchronously to environmental change when the elevation ranges of vegetation types and their associated vertebrates expand or contract in the same direction. Conversely, the response is asynchronous when the elevation ranges of vegetation types and associated vertebrates change in different directions. The capacity of vertebrate species to respond synchronously with change in the elevation ranges of the vegetation that comprises their habitat is likely a function of their ecological traits. Here we combine measures of elevation range shifts in 23 vertebrate species with those of their associated vegetation types across 80 yr, on a large elevation transect in California's Sierra Nevada mountains that encompasses Yosemite National Park. Half the species’ shifts were synchronous with vegetation shifts, ¼ of the species were asynchronous, and the others showed no relationship. Most species that responded synchronously to changes in vegetation elevation ranges expanded their elevation range, and are inhabitants of low and intermediate elevations. In contrast, those species whose range shifts were asynchronous to associated vegetation shifts inhabit high elevations. These species experienced contraction in elevation range even while their associated vegetation types expanded. However, these species were responding synchronously to a subset of their associated vegetation types. Considering trait‐based predictors, omnivores were more synchronous than herbivores. Our results on synchronous and asynchronous elevation shifts with vegetation may permit more accurate modeling of future ranges for vertebrates in California's Sierra Nevada. The approach also offers a new method for use in assessment of vertebrate vulnerability in other mountain regions, and can be an important component of assessing their vulnerability to climate change.     

Agaricales found in the Godhavn area, W Greenland

The agaric flora of the Godhavn region (W Greenland 69°15'–69°30'N) was studied by the authors in 1967, 1970–72, and 1977. 1125 collections were made and 150 taxa were recognized. It was found that the fungus flora varied very much in the different seasons. The authors attempt to join their experience from studies in other arctic and alpine areas. In total, the check–list shows that there is a large degree of similarity between the agaric flora of the Godhavn area and that of the Alps and the Scandinavian mountains, while the similarity with the European lowland flora is less than earlier assumed. A bibliography of the relevant literature is appended.     

The moss mites of Yes Tor, Dartmoor, Devon (Acari: Oribatida) and their evolutionary significance

A species list of oribatid mites collected from the summit of Yes Tor, Dartmoor, is given, together with notes on their distribution. Yes Tor lies south of latitude 51° in that part of Britain which remained ice free during the Pleistocene. The species found on Yes Tor are compared with the species recorded from the summits of 11 mountains lying north of latitude 53°, which were all ice-covered at the period of maximum glaciation. In the case of Yes Tor and these 11 northern montane sites, three similar faunal elements have been identified arctic-alpine species, European-alpine species and a group of British montane species that are also common in the lowlands. The view is advanced that the similarity of the montane oribatid fauna of Yes Tor with that of the mountains to the north of latitude 53° has resulted from the probable movements of the mites during Quaternary and postglacial times over an area extending from the Arctic Circle to the Mediterranean. It is suggested that these movements, while being largely spontaneous, have also been aided by transportation agents, both physical and biological.     

Response of copronecrophagous beetle communities to habitat disturbance in two mountains of the Mexican Transition Zone: influence of historical and ecological factors

We analyze the influence of historical and ecological factors on the diversity and composition of communities of copronecrophagous beetles associated with conserved and disturbed habitats on two mountains of the Mexican Transition Zone: one mountain of xeric (Las Derrumbadas) and the other of temperate (El Pinal) climate. We collected a total of 1113 beetles of 14 species. While abundance was similar between mountains, the number of species found on the temperate mountain (589 individuals: 11 species) was higher than on the xeric mountain (524 individuals: 5 species). On the temperate mountain, the disturbed habitat was approximately twice as diverse as the conserved habitat, while the opposite pattern was observed on the xeric mountain. Analysis of species turnover between mountains indicated the presence of two relatively different communities and the magnitude of the species turnover related to habitat disturbance depended on the type of mountain, having a higher turnover between habitat types in the temperate mountain. The xeric mountain was dominated by species belonging to the Paleoamerican Plateau distribution pattern, while the Paleoamerican Montane pattern dominated on the temperate mountain, whose species increased their abundance in disturbed habitats together with species of Nearctic affinity. Our results suggest a negative effect of habitat disturbance on the xeric mountain. While on the temperate mountain, beetle diversity seems to increase with disturbance. These results reiterate the need to consider regional-scale historical and ecological processes in order to understand the effects of disturbance and permit the establishment of conservation strategies to adequately protect the organisms, as well as the functions they provide for natural and anthropic ecosystems alike.     

Elevational Gradient of Vascular Plant Species Richness and Endemism in Crete – The Effect of Post-Isolation Mountain Uplift on a Continental Island System

Understanding diversity patterns along environmental gradients and their underlying mechanisms is a major topic in current biodiversity research. In this study, we investigate for the first time elevational patterns of vascular plant species richness and endemism on a long-isolated continental island (Crete) that has experienced extensive post-isolation mountain uplift. We used all available data on distribution and elevational ranges of the Cretan plants to interpolate their presence between minimum and maximum elevations in 100-m elevational intervals, along the entire elevational gradient of Crete (0–2400 m). We evaluate the influence of elevation, area, mid-domain effect, elevational Rapoport effect and the post-isolation mountain uplift on plant species richness and endemism elevational patterns. Furthermore, we test the influence of the island condition and the post-isolation mountain uplift to the elevational range sizes of the Cretan plants, using the Peloponnese as a continental control area. Total species richness monotonically decreases with increasing elevation, while endemic species richness has a unimodal response to elevation showing a peak at mid-elevation intervals. Area alone explains a significant amount of variation in species richness along the elevational gradient. Mid-domain effect is not the underlying mechanism of the elevational gradient of plant species richness in Crete, and Rapoport''s rule only partly explains the observed patterns. Our results are largely congruent with the post-isolation uplift of the Cretan mountains and their colonization mainly by the available lowland vascular plant species, as high-elevation specialists are almost lacking from the Cretan flora. The increase in the proportion of Cretan endemics with increasing elevation can only be regarded as a result of diversification processes towards Cretan mountains (especially mid-elevation areas), supported by elevation-driven ecological isolation. Cretan plants have experienced elevational range expansion compared to the continental control area, as a result of ecological release triggered by increased species impoverishment with increasing elevation.     

Species-specific cell mobility of bacteria-feeding myxamoebae in plasmodial slime molds

On decaying wood or litter in forests, plasmodial slime molds (myxomycetes) represent a large fraction of eukaryotic protists that feed on bacteria. In his seminal book Experimental Physiology of Plants (1865), Julius Sachs referred to the multinucleate plasmodium of myxomycetes, which were considered at that time as primitive plants (or fungi). Today it is well established that myxomycetes are members of the Amoebozoa (Protista). In this study we compare the mobility of myxamoebae of 3 European species, Lycogala epidendrum (order Liceales), Tubulifera arachnoidea, and Trichia decipiens (order Trichiales). Using agar plates, on which 3 separate bacterial species were cultivated as prey organisms (Methylobacterium mesophilicum, Escherichia coli, Agrobacterium tumefaciens), we document large differences in cell motility between the myxomycetes investigated. In addition, we show that the 3 species of myxamoebae can be distinguished based on their average cell size. These data shed light on the mode of co-occurrence via differential substrate utilization in these members of the Amoebozoa.     

Myxomycete diversity and distribution from the fossil record to the present

The myxomycetes (plasmodial slime molds or myxogastrids) are a group of eukaryotic microorganisms usually present and sometimes abundant in terrestrial ecosystems. Evidence from molecular studies suggests that the myxomycetes have a significant evolutionary history. However, due to the fragile nature of the fruiting body, fossil records of the group are exceedingly rare. Although most myxomycetes are thought to have very large distributional ranges and many species appear to be cosmopolitan or nearly so, results from recent studies have provided evidence that spatial distribution patterns of these organisms can be successfully related to (1) differences in climate and/or vegetation on a global scale and (2) the ecological differences that exist for particular habitats on a local scale. A detailed examination of the global distribution of four examples (Barbeyella minutissima, Ceratiomyxa morchella, Leocarpus fragilis and Protophysarum phloiogenum) demonstrates that these species have recognizable distribution patterns in spite of the theoretical ability of their spores to bridge continents. Special Issue: Protist diversity and geographic distribution. Guest editor: W. Foissner.