Mountain Ecotones Research Articles

Canada lynx (Lynx canadensis) gene flow across a mountain transition zone in western North America

Mountain ecotones have the potential to cause multiple patterns in divergence, from simple barrier effects to more fundamental ecological divergence. Most work in mountain ecotones in North America has focused on reinforcement between refugial populations, making prediction of how mountains impact species that are not restricted to separate glacial refugia remains difficult. This study focused on the Canada lynx (Lynx canadensis Kerr, 1792), a highly mobile felid considered to be a habitat and dietary specialist. Specifically, we used 14 microsatellite loci and landscape genetic tools to investigate if the Rocky Mountains and associated climatic transitions influence lynx genetic differentiation in western North America. Although lynx exhibited high gene flow across the region, analyses detected structuring of neutral genetic variation across our study area. Gene flow for lynx most strongly related to temperature and elevation compared with other landscape variables (terrain roughness, percent forest cover, and habitat suitability index) and geographic distance alone. Overall, genetic structure in lynx is most consistent with barrier effects created by the Rocky Mountains rather than ecological divergence. Furthermore, warmer temperatures had a measurable impact on gene flow, which suggests connectivity may further decrease in peripheral or fragmented populations as climate warms.

Forest Phenology Dynamics to Climate Change and Topography in a Geographic and Climate Transition Zone: The Qinling Mountains in Central China

Forest ecosystems in an ecotone and their dynamics to climate change are growing ecological and environmental concerns. Phenology is one of the most critical biological indicators of climate change impacts on forest dynamics. In this study, we estimated and visualized the spatiotemporal patterns of forest phenology from 2001 to 2017 in the Qinling Mountains (QMs) based on the enhanced vegetation index (EVI) from MODerate-resolution Imaging Spectroradiometer (MODIS). We further analyzed this data to reveal the impacts of climate change and topography on the start of the growing season (SOS), end of the growing season (EOS), and the length of growing season (LOS). Our results showed that forest phenology metrics were very sensitive to changes in elevation, with a 2.4 days delayed SOS, 1.4 days advanced EOS, and 3.8 days shortened LOS for every 100 m increase in altitude. During the study period, on average, SOS advanced by 0.13 days year−1, EOS was delayed by 0.22 days year−1, and LOS increased by 0.35 day year−1. The phenological advanced and delayed speed across different elevation is not consistent. The speed of elevation-induced advanced SOS increased slightly with elevation, and the speed of elevation-induced delayed EOS shift reached a maximum value of 1500 m from 2001 to 2017. The sensitivity of SOS and EOS to preseason temperature displays that an increase of 1 °C in the regionally averaged preseason temperature would advance the average SOS by 1.23 days and delay the average EOS by 0.72 days, respectively. This study improved our understanding of the recent variability of forest phenology in mountain ecotones and explored the correlation between forest phenology and climate variables in the context of the ongoing climate warming.

Study on optimized combination and utilization model of agricultural and animal husbandry resources in mountain ecotone

[Purpose] The development of agriculture and animal husbandry in Tibet is basically based on the interlaced development of agriculture and animal husbandry in mountainous areas. The interlaced agricultural and animal husbandry areas in mountainous areas are the unity of special, harmonious and harmonious regional small environment. The special attributes of mountainous areas determine the rich agricultural and animal husbandry resources, ecological development cycle areas, characteristic agricultural products areas and tourism. The division and regionalization of recreational zones and the optimal combination and utilization of agricultural and animal husbandry resources in mountainous ecotone have very important effects on promoting the benign cycle of regional agricultural and animal husbandry economic development, the development of urban integration and the protection of industrial ecological environment. How to develop and construct a new type of "environment-friendly and resource-saving" agricultural and animal husbandry areas is very important. It is of great practical significance to promote the development of regional agriculture and animal husbandry industry, to establish an efficient production system of agriculture and animal husbandry and to speed up the increase of farmers' and herdsmen's income. Rational and effective utilization of various beneficial resources can effectively solve the problems of material shortage, resource shortage and contradiction between supply and demand, and ensure the interlaced agriculture and animal husbandry economy in Tibet's mountainous areas. Sustainable development. [Method]On the basis of domestic and foreign literatures, this paper analyses and evaluates in detail the optimal combination and utilization mode of agricultural and animal husbandry resources in mountainous ecotone area by means of management induction, [Result]that is, the modern high-efficiency utilization mode of new energy, the green integration development mode of "chain fusion" in seed and culture, and the multi-level agricultural capital. Four basic modes, i.e. the mode of efficient utilization of resources and the mode of recreational sightseeing and sightseeing in mountainous agriculture and animal husbandry. [Conclusion] The above four modes of optimal combination and utilization of agricultural and animal husbandry resources are the basic macro-combination modes of agricultural and animal husbandry resources in the mountainous ecotone of Tibet. They are discussed in detail from the perspectives of natural resources utilization, agricultural products production and processing, agricultural and animal husbandry production and construction, and eco-tourism development in order to provide better services. Development and construction of agricultural and animal husbandry circular economy in Tibet. Finally, according to the characteristics of Tibet's own development, this paper puts forward to promote the integration of scientific concepts, the strength of scientific and technological support, and the fund guarantee system in the basic fields, and to strengthen the integration of farmer-herdsman cooperatives and market organizations in practical application. Reference and extension of the model, incentive and compensation security system, etc., for the future development of mountain-type interlaced agriculture and animal husbandry in Tibet circular agricultural and animal husbandry and resource optimization and combination of construction to provide a reference and research results.

Characters of ecosystem vulnerability in southwestern China based on vegetation productivity

Southwestern China is one of the most important areas for global biodiversity conservation. Under the background of global climate change, the vulnerability of this area has showed an increasing trend. According to the IPCC concept of vulnerability, we calculated the spatial distribution of ecosystem's vulnerability in southwestern China based on gross primary productivity (GPP) and then analyzed the spatial variation of different levels of vulnerability. Besides, we analyzed the relationship between environmental factors and ecosystem vulnerability, including precipitation, temperature, altitude, slope and vegetation type. The results showed that ecosystem vulnerability in the southwestern China gradually increased from southeast to northwest, with most area within the region being slight and mild vulnerable area (together occupied 69% of the total). The vulnerability level decreased with the increasing of mean annual precipitation and temperature but increased with increasing elevation and slope. Karst area in southwest and borders between farming and ranging regions in northwest Mountain ecotone of the study area had higher vulnerability, being more easily affected by climate change or other disturbances. The vulnerabilities of needle-leaved forest, grassland, and shrubland were relatively higher than other vegetation types, with the potential to be more easily affected by climate change.

Invasion of Siberian Pine Populations in Mountain Tundra in the Northern Urals

A new method for determining the upper forest border (UFB) as the border of the “root-closed” stand and regrowth as its potential vanguard is proposed. The mass dispersal of Pinus sibirica populations by the nutcracker (Nucifraga caryocatactes) in the UFB ecotone in the Northern Urals (Pavdinskii Kamen’ and Tretii Bugor Mountain) from the middle-mountain taiga to the mountain forest tundra and tundra at a distance reaching 1 km is found. It is done based on the original reconstruction method of the dynamics of population number in P. sibirica annual seedlings and on an analysis of their relations with the dynamics of the seed bearing and population number of the nutcracker. The trustworthy consortive relations of the number of Pinus sibirica generations in the mountain forested tundra and tundra zones, with its seed bearing and nutcracker number in the previous year in the middle-mountain taiga zone, are found. A significant increase, 3.7 times, in the number of seedling generations during the last 49 years is found in connection with the increase in the summer air temperature in the subarctic to 2.0°C. A hypothesis of the formation of the united genetic metapopulation of P. sibirica in the forest–tundra mountain ecotone zone as a consequence of its seed ornitochory from the highly different populations is formulated. A forecast of the mosaic formation of the vanguard “thin forests” in 20–25 years and the root-closed curtains of the forest in 40–50 years in the mountain tundra of the Northern Urals at the current rate of the rise in temperature is made.

Tree growth and regeneration dynamics at a mountain ecotone on Changbai Mountain, northeastern China: Which factors control species distributions?

To improve our understanding of climate-driven long-term dynamics of eastern Asian mountain forests, we used field surveys and dendrochronological techniques to examine regeneration density, growth rate of mature trees, and growth sensitivity to climate of 3 common coniferous tree species at their respective altitudinal distribution limits on Changbai Mountain, northeastern China. The studied species were Manchurian fir (Abies nephrolepis, distributed between 780 and 1750 m asl), Korean pine (Pinus koraiensis, 780 and 1300 m asl), and Jezo spruce (Picea jezoensis var. komarovii, 1000 and 1750 m asl). Regeneration densities did not differ significantly among the elevations except for Jezo spruce, which showed a significantly lower regeneration density at 1000 m asl as compared to 1300 and 1750 m asl. All 3 species showed a significantly higher basal area increment (BAI) at the middle part of their distribution ranges than at their limits. The growth of Manchurian fir and Jezo spruce exhibited higher sensitivity to precipitation than to temperature at their lower distribution limits, and the inverse pattern was observed at the upper limit. In all cases the correlations between growth and the respective climate variable were positive, except for the correlation between Jezo spruce growth and precipitation. Growth of Korean pine was positively correlated with spring temperature and summer moisture at its lower distribution limit and with summer temperature at its upper limit. Our study suggests that elevational limits of forest vegetation were likely constrained by climate factors affecting growth of dominant species rather than those controlling regeneration density.

Comparing the Response of Birds and Butterflies to Vegetation-Based Mountain Ecotones Using Boundary Detection Approaches

Mountains provide an opportunity to examine changes in biodiversity across environmental gradients and areas of transition (ecotones). Mountain ecotones separate vegetation belts. Here, we aimed to examine whether transition areas for birds and butterflies spatially correspond with ecotones between three previously described altitudinal vegetation belts on Mt. Hermon, northern Israel. These include the Mediterranean Maquis, xero-montane open forest and Tragacanthic mountain steppe vegetation belts. We sampled the abundance of bird and butterfly species in 34 sampling locations along an elevational gradient between 500 and 2200 m. We applied wombling, a boundary-detection technique, which detects rapid changes in a continuous variable, in order to locate the transition areas for bird and butterfly communities and compare the location of these areas with the location of vegetation belts as described in earlier studies of Mt. Hermon. We found some correspondence between the areas of transition of both bird and butterfly communities and the ecotones between vegetation belts. For birds and butterflies, important transitions occurred at the lower vegetation ecotone between Mediterranean maquis and the xero-montane open forest vegetation belts, and between the xero-montane open forest and the mountain steppe Tragacanthic belts. While patterns of species turnover with elevation were similar for birds and butterflies, the change in species richness and diversity with elevation differed substantially between the two taxa. Birds and butterflies responded quite similarly to the elevational gradient and to the shift between vegetation belts in terms of species turnover rates. While the mechanisms generating these patterns may differ, the resulting areas of peak turnover in species show correspondence among three different taxa (plants, birds and butterflies).

A new method to infer vegetation boundary movement from ‘snapshot’ data

Global change may induce shifts in plant community distributions at multiple spatial scales. At the ecosystem scale, such shifts may result in movement of ecotones or vegetation boundaries. Most indicators for ecosystem change require timeseries data, but here a new method is proposed enabling inference of vegetation boundary movement from one ‘snapshot’ (e.g. an aerial photograph or satellite image) in time. The method compares the average spatial position of frontrunners of both communities along the vegetation boundary. Mathematical analyses and simulation modeling show that the average frontrunner position of retreating communities is always farther away from a so‐called optimal vegetation boundary as compared to that of the expanding community. This feature does not depend on assumptions about plant dispersal or competition characteristics. The method is tested with snapshot data of a northern hardwood‐boreal forest mountain ecotone in Vermont, a forest‐mire ecotone in New Zealand and a subalpine treeline‐tundra ecotone in Montana. The direction of vegetation boundary movement is accurately predicted for these case studies, but we also discuss potential caveats. With the availability of snapshot data rapidly increasing, the method may provide an easy tool to assess vegetation boundary movement and hence ecosystem responses to changing environmental conditions.

Community structure and seasonal variation of soil arthropods in the forest-steppe ecotone of the mountainous region in Northern Hebei, China

Soil fauna have been receiving more and more attention because they play an important role in nutrient cycling. However, there is a lack of information on soil arthropods in the forest-steppe ecotone in the mountainous region of northern Hebei, which makes it difficult to meet the need of protecting biodiversity in this area. Soil arthropod communities were investigated in the forest-steppe ecotone in northern Hebei province to provide basic information on changes in mountain soil fertility, which could promote the development of soil arthropod communities in mountain ecotones. From the preliminary identification, a total of 7994 individual soil arthropods were collected, which belonged to 25 groups, 6 classes and 24 orders. Acarina, Hymenoptera and Collembola were the dominant groups in the ecotone. The number of Acarina was higher than Collembola, and this phenomenon was obviously different from other areas in the same climate zone. The increased abundance of rare groups in the Forest zone with the richer vegetation, higher arthropod abundance and more substantial litter depth, could be interpreted as a reaction to the suitable soil environment and food supply. And these rare groups were sensitive to environmental changes, which could be regarded as biotic indicators for evaluating soil quality. The analysis of community diversity showed that the abundance index (d), the Shannon-Wiener index (H′), the evenness index (J) and the density-group index (DG) were significantly higher in the forest zone, lower in the forest-steppe zone, and lowest in the meadow-steppe zone. Seasonal variations in community composition correlated with changes in average air temperature and precipitation in this ecotone. Groups and individuals of soil arthropod communities in the three zones were present in greater numbers in the middle of the rainy season than in the early or late periods of the rainy season as a whole. At the same time, seasonal changes in soil arthropod communities from different plots were also influenced by habitat condition.

Spatio-temporal analysis of alpine ecotones: A spatial explicit model targeting altitudinal vegetation shifts

There is general agreement in literature that Alpine vegetation belt ecotones have shown a trend of upward migration in the last few decades. Despite the potential of such shifts as indicators of global change effects in mountain ecosystems, there are relatively few works focused on their assessment in a systematic and spatially explicit way. In this work our aim is to quantify the altitudinal shifts and analyse the spatial pattern dynamics of mountain ecotones. We developed a novel procedure to delineate the current and former state of three characteristic mountain ecotones, which we formalised as forest, tree and tundra lines. Our approach is based on the recognition of altitudinal extreme outposts identified with ecotone locations at a slope scale. The integration of multi-temporal datasets allows the identification and quantification of altitudinal advances and retreats in the outpost locations for a given period. We tested the method in a section of the Italian Alps for the period 1957–2003. Results show a general trend of an increase in altitude for the three ecotones, despite the occurrence of occasional decreases. We estimate decadal altitude increments of 25 m for forest line, 13 m for treeline and 11 m for tundra line. We also identified changes in ecotone spatial morphology between the two dates, with significant implications in connectivity and colonisation dynamics.

Ecotones in Mountain Environments: Illustrating Sensitive Biogeographical Boundaries with Remotely Sensed Imagery in the Geography Classroom

Application of remotely sensed imagery is useful for examining ecosystem response to environmental change. This paper illustrates the utility of satellite images and aerial photography for examining mountain ecotones for biogeographical classroom instruction. Using imagery from Waterton‐Glacier International Peace Park to explore differences in ecotone boundaries, we focused on descriptive physical features found in these special communities: alpine treeline, montane forest/grassland (lower treeline), subalpine meadows, ribbon forest, and avalanche path edges. We determined that differences and similarities in scale, resolution, and spectral properties between satellite and aerial imagery are important in discerning temporal and spatial change of physical features in ecotones. We hope the examples illustrated in this paper will prove useful to teachers as they examine changes in mountain environments.

The potential negative impacts of global climate change on tropical montane cloud forests

Nearly every aspect of the cloud forest is affected by regular cloud immersion, from the hydrological cycle to the species of plants and animals within the forest. Since the altitude band of cloud formation on tropical mountains is limited, the tropical montane cloud forest occurs in fragmented strips and has been likened to island archipelagoes. This isolation and uniqueness promotes explosive speciation, exceptionally high endemism, and a great sensitivity to climate. Global climate change threatens all ecosystems through temperature and rainfall changes, with a typical estimate for altitude shifts in the climatic optimum for mountain ecotones of hundreds of meters by the time of CO 2 doubling. This alone suggests complete replacement of many of the narrow altitude range cloud forests by lower altitude ecosystems, as well as the expulsion of peak residing cloud forests into extinction. However, the cloud forest will also be affected by other climate changes, in particular changes in cloud formation. A number of global climate models suggest a reduction in low level cloudiness with the coming climate changes, and one site in particular, Monteverde, Costa Rica, appears to already be experiencing a reduction in cloud immersion. The coming climate changes appear very likely to upset the current dynamic equilibrium of the cloud forest. Results will include biodiversity loss, altitude shifts in species' ranges and subsequent community reshuffling, and possibly forest death. Difficulties for cloud forest species to survive in climate-induced migrations include no remaining location with a suitable climate, no pristine location to colonize, migration rates or establishment rates that cannot keep up with climate change rates and new species interactions. We review previous cloud forest species redistributions in the paleo-record in light of the coming changes. The characteristic epiphytes of the cloud forest play an important role in the light, hydrological and nutrient cycles of the cloud forest and are especially sensitive to atmospheric climate change, especially humidity, as the epiphytes can occupy incredibly small eco-niches from the canopy to crooks to trunks. Even slight shifts in climate can cause wilting or death to the epiphyte community. Similarly, recent cloud forest animal redistributions, notably frog and lizard disappearances, may be driven by climate changes. Death of animals or epiphytes may have cascading effects on the cloud forest web of life. Aside from changes in temperature, precipitation, and cloudiness, other climate changes may include increasing dry seasons, droughts, hurricanes and intense rain storms, all of which might increase damage to the cloud forest. Because cloud forest species occupy such small areas and tight ecological niches, they are not likely to colonize damaged regions. Fire, drought and plant invasions (especially non-native plants) are likely to increase the effects of any climate change damage in the cloud forest. As has frequently been suggested in the literature, all of the above factors combine to make the cloud forest a likely site for observing climate change effects in the near future.