Northern Range Research Articles

THE FIRST DATA ON MICROTURBELLARIANS (PLATHELMINTHES, RHABDITOPHORA) OF THE BOGUCHANSKY RESERVOIR. 1. KALYPTORHYNCHIA OF BAIKAL ORIGIN, WITH DESCRIPTIONS OF THREE NEW SPECIES

This series of reports is devoted to taxonomic investigations of the microturbellarian fauna (Plathelminthes, Rhabditophora) of the Boguchansky reservoir, lower flow of the Angara River, eastern Siberia. The first report provides information about ten species of Kalyptorhynchia (Rhynchokarlingiidae) previously described from Lake Baikal. Three of them are new species, all described in the present paper. The new species of Kalyptorhynchia belong to the genera Mariareuterella Timoshkin Grygier 2005, Riedelella Timoshkin 2004 and Rhynchokarlingia Timoshkin et Mamkaev 2004, respectively. A species with five cuticular hooks in the male copulatory apparatus is discovered for the first time. The diagnosis of the genus Rhynchokarlingia is expanded. All species are found in the lower reaches of Angara River. Rhynchokarlingiidae is a family of kalyptorhynchian worms autochthonous in Baikal. It seems logical to assume that all newly described species are also of Baikal origin. Endemic Baikal Kalyptorhynchia are found for the first time in an area so remote (about 1400 km) from Lake Baikal. Our records significantly expand the distribution area of Rhynchokarlingiidae, with the Boguchanskoye reservoir of Angara River to be considered as the northern range limit of their distribution. Illustrated descriptions of nine species (including three new ones), comparisons with previously described taxa, information on distribution and brief ecological data are also given.

Morphological and Molecular Study of the Fish Parasitic Crustaceans Cymothoa indica and Mothocya collettei (Isopoda: Cymothoidae), with New Distribution Records

Cymothoidae are parasitic isopods that infest fishes inhabiting marine, brackish, and fresh-water environments. The systematics, distribution, and host specificity of cymothoids is often unknown. In this study, morphological observations and molecular analysis using the COI and 16S rRNA genes were conducted on a juvenile individual of Cymothoa indica infesting the wide-banded hardyhead silverside, Atherinomorus lacunosus, and an ovigerous female of Mothocya collettei infesting the hound needlefish, Tylosurus crocodilus, both collected from Okinawa Island, Japan. This is the first time that these two species of cymothoid have been collected in the Ryukyu Islands, and the juvenile C. indica in particular represents a new northern range limit for its species. That specimen was identified using molecular analysis and showed almost identical morphology to previously reported juveniles, but it differed in the numbers of robust setae on pereopods 6 and 7. The ovigerous female of M. collettei showed a high morphological similarity to M. collettei but had some morphological traits consistent with Mothocya affinis. DNA analysis indicated that these two nominal species of Mothocya are very closely related, and morphological and molecular studies using larger populations of both are needed.

Non-linear effects on the population performance of Bighead Carp under different maturation schedules

Bighead Carp currently threatens to invade the Laurentian Great Lakes from the Mississippi River, but the novel climatic conditions it will encounter by expanding northwards could affect its population performance. Bighead Carp in colder climates exhibits slower growth and matures later, with later maturation typically leading to larger adult size and increased fecundity and survival. Accordingly, the life-history strategies of Bighead Carp at its northern range limits could differ from those observed in its current invaded range. To explore how population performance could differ across changing environmental conditions, we used a stage- and age-based matrix population model parameterized with values reported for Bighead Carp populations around the world. The model was used to evaluate how different ages of maturity and their resulting impacts to body size, survival, and fecundity could impact rates of population growth and establishment. Age of maturity had a non-linear effect on population growth, with maturation at intermediate ages (4–6 years) resulting in better performance. However, performance differed less between maturation ages when fecundity was allowed to increase disproportionately with body size. Greater population growth at younger ages of maturity suggest that invasion at lower latitudes could enable establishment in fewer years due to faster rates of development in warmer temperatures. Across all maturation schedules, population growth was most sensitive to the recruitment of age-1 individuals and least sensitive to adult survival, and vital rates overall varied more in their contribution to population growth at younger ages of maturity. Thus, understanding the factors that control age-1 recruitment would inform projections of population performance for Bighead Carp in the Laurentian Great Lakes.

Bison alter the northern Yellowstone ecosystem by breaking aspen saplings.

The American bison (Bison bison) is a species that strongly interacts with its environment, yet the effects of this large herbivore on quaking aspen (Populus tremuloides) have received little study. We documented bison breaking the stems of aspen saplings (young aspen >2 m tall and ≤5 cm in diameter at breast height) and examined the extent of this effect in northern Yellowstone National Park (YNP). Low densities of Rocky Mountain elk (Cervus canadensis) after about 2004 created conditions conducive for new aspen recruitment in YNP's northern ungulate winter range (northern range). We sampled aspen saplings at local and landscape scales, using random sampling plots in 87 randomly selected aspen stands. Across the YNP northern range, we found that 18% of sapling stems had been broken. The causal attribution to bison was supported by multiple lines of evidence: (1) most broken saplings were in areas of high bison and low elk density; (2) saplings were broken in summer when elk were not foraging on them; (3) we directly observed bison breaking aspen saplings; and (4) mixed-effects modeling showed a positive association between scat density of bison and the proportion of saplings broken. In a stand heavily used by bison, most aspen saplings had been broken, and portions of the stand were cleared of saplings that were present in previous sampling in 2012. Bison numbers increased more than fourfold between 2004 and 2015, and their ecosystem effects have similarly increased, limiting and in some places reversing the nascent aspen recovery. This situation is further complicated by political constraints that prevent bison from dispersing to areas outside the park. Thus, one important conservation goal, the preservation of bison, is affecting another long-term conservation goal, the recovery of aspen and other deciduous woody species in northern Yellowstone.

Establishment and postrelease recovery of Laricobius nigrinus and Laricobius osakensis (Coleoptera: Derodontidae), released for biological control of Adelges tsugae (Hemiptera: Adelgidae), in the Northeastern United States.

Hemlock woolly adelgid (HWA), Adelges tsugae Annand, is a major forest pest in the eastern United States responsible for killing millions of eastern hemlock, Tsuga canadensis (L.) Carrière and Carolina hemlock, T. caroliniana Engelmann. The US biological control program for HWA has largely invested in the rearing and release of Laricobius nigrinus Fender and more recently L. osakensis Montgomery and Shiyake. Though the establishment of L. nigrinus has been well-documented in the southern, mid-Atlantic, and coastal portions of the northeastern United States, documentation in interior areas of the northeastern United States is limited. Establishment of L. osakensis in the northeastern United States has not yet been documented. Release locations in the northeastern United States were surveyed for L. nigrinus and L. osakensis establishment to examine the relationship between establishment success and winter temperatures, as winter minimum temperatures likely limit the northern range of introduced Laricobius species. Our results suggest that L. nigrinus establishment is limited by winter minimum temperatures and that the probability of establishment declines as absolute minimum temperature declines. We found L. nigrinus established at sites in Maine, New York, and Pennsylvania, but did not recover any L. nigrinus in Massachusetts, New Hampshire, or Vermont. Similarly, we found L. osakensis established at sites in New York and Pennsylvania and recovered individuals in Maine, though further sampling is necessary to confirm presence of the F3 generation. We also report the first field observation of reproduction of silver flies, Leucotaraxis argenticollis (Diptera: Chamaemyiidae), released predator of HWA, in the eastern United States.

The northern range of rare plant species in the NE Fennoscandia between historical and recent climatic changes: the case of Eriophorum gracile (Cyperaceae)

The northern range of rare plant species in the NE Fennoscandia between historical and recent climatic changes: the case of Eriophorum gracile (Cyperaceae)

Evolution of the Xerocarpa clade (Opuntia; Opuntieae): Evidence for the Role of the Grand Canyon in the Biogeographic History of the Iconic Beavertail Cactus and Relatives.

The formation of the western North American drylands has led to the evolution of an astounding diversity of species well adapted for such communities. Complex historical patterns often underlie the modern distribution of the flora and fauna of these areas. We investigated the biogeography of a group of desert-adapted prickly pears, known as the Xerocarpa clade, from western North America. The Xerocarpa clade originated in the mid-late Pliocene, likely on the Colorado Plateau, and then moved south into the Mojave, Sonoran, and Chihuahuan deserts, and California montane regions, further diversifying, mostly into the Quaternary. The southward trajectory of the clade was likely greatly influenced by the formation of the Grand Canyon. The synapomorphy of dry fruit presumably impeded the long-distance dispersibility of the beavertail cactus, Opuntia basilaris, while dry, spiny fruit may have enabled O. polyacantha to substantially increase its distribution. Opuntia basilaris evolved a pubescent epidermis, allowing it to invade hotter, drier conditions, while the spine-clothed stems of O. polyacantha may have given it an advantage for increasing its northern range into colder environments. The Xerocarpa clade shows a cold desert origin, and changes in morphological characters have made these sister taxa well adapted for invading broadscale, but oftentimes contrasting habitats.

Postglacial establishment and expansion of marginal populations of sugar maple in western Québec, Canada: Palynological detection and interactions with fire, climate and successional processes

An isolated sugar maple ( Acer saccharum Marsh.) stand is located in the boreal forest of Abitibi, about 75 km beyond its present northern range limit. When did this relatively thermophilous tree species establish after ice retreat? Were its populations more abundant than now sometimes in the past? If so, when and how did they expand then retracted? How did the species persist in boreal forest over time? What could have been the role of fire on this stand? To answer those questions, we reconstructed the postglacial fire and vegetation history from three lacustrine sediment sequences distributed along a c. 180 km latitudinal transect from southern boreal forests to the northern portion of deciduous forests. From north to south, those are lakes Labelle, Chasseur and Fur. We explored a procedure based on pollen accumulation rates in order to detect the probable presence of sugar maple within the lakes’ watershed. The procedure successfully indicates a sugar maple establishment c. 7800–5100 cal. BP at Fur, 5500–4400 cal. BP at Chasseur and c. 4000–2700 cal. BP at Labelle, in the north. At Fur, the subsequent sugar maple expansion happened 1 to 2 thousand years after establishment, during colder and moister climatic conditions favoring Pinus strobus L. replacement by Betula spp. c. 6000–5000 cal. BP. Sugar maple establishment, persistence or expansion is apparently not linked to a change in fire activity at Fur and Chasseur, but at Labelle, the species was more abundant during periods of shorter fire return intervals from 2000 to 500 years ago. Our study suggests that northern (Chasseur and Labelle) sugar maple establishment and possible expansion was probably more controlled by a complex interaction of inhibition and facilitation dynamics than by climate alone, a process reliant on the dominant vegetation’s composition and structure.

Asymmetric glaciation, divide migration, and postglacial fluvial response times in the Qilian Shan

Abstract Glacial-interglacial cycles have repeatedly perturbed climate and topography in many midlatitude mountain ranges during the Quaternary. Glacial erosion can move drainage divides and induce fluvial adjustments downstream, yet the time scale over which these adjustments occur remains unclear. We examined landscape evolution in the northwest-southeast–trending Qilian Shan, where the contrast in solar insolation between north- and south-facing slopes has generated larger glaciers on the northern range crest. Our analyses suggest that this asymmetric glaciation has caused southward migration of the main drainage divide, prompting river channels below the extents of ice on north-facing slopes to become oversteepened for their drainage area and channels on south-facing slopes to become analogously understeepened. These changes in steepness should accelerate or slow down postglacial fluvial incision, even in the regions where topography has not been directly modified by glacial erosion. Numerical modeling suggests these discrepancies persist for millions of years, much longer than the duration of recent glacial-interglacial cycles, implying a widespread and enduring influence of intermittent glaciations on landscape evolution in glaciated mountain ranges during the Quaternary.

Strong latitudinal gradient in temperature-growth coupling near the treeline of the Canadian subarctic forest

Boreal forests are experiencing severe climatic changes that vary widely across the broad geographic distribution of the biome. The changes are greatest near the subarctic treeline where trees often exhibit high climatic sensitivity because climatic conditions approach the limits of their physiological tolerance. Despite the importance of subarctic boreal forests, the lack of field-acquired growth data remains a critical issue that limits the generalization of forest productivity models across the entire boreal biome. Using tree-ring chronologies from remote stands distributed along three latitudinal gradients ranging from 65 to 102°W, we investigated recent trends in black spruce growth and their relationships with recent climate warming near the subarctic treeline in eastern Canada. Our results show a generally positive effect of temperature and a negative effect of precipitation, both indicating that black spruce growth is temperature-limited near its northern range limit. However, we observed a strong gradient in temperature-growth coupling within a small latitudinal gradient (about one degree of latitude), where strong temperature constraints appear limited to the northernmost, coldest stands. Moreover, the positive growth response to temperature decreased from wetter to dryer sites and climate-growth coupling declined over the study period in the driest sites. These results suggest that the growth increase associated with warmer temperature may be limited by reduced precipitation and potential moisture limitation. Lastly, our results suggest that acute climatic events have the potential to induce abrupt shifts in tree climate-growth relationships. Such results indicate that the expected beneficial effect of warming on high latitude tree growth may be less generalized and more complex than previously thought in northeastern Canada, perhaps due to factors other than temperature, which might confound the climate-growth coupling southwards. Thus, our results highlight the need for a better understanding of additional growth drivers in these poorly studied regions and for physiologically informed definitions of acute climatic events, in order to refine broad-scale forest productivity modeling.

Multiscale assessment of habitat selection and avoidance of sympatric carnivores by the endangered ocelot

Habitat selection by animals is a complex, dynamic process that can vary across spatial and temporal scales. Understanding habitat selection is a vital component of managing endangered species. Ocelots (Leopardus pardalis), a medium-sized endangered felid, overlap in their northern range with bobcats (Lynx rufus) and coyotes (Canis latrans), with all three species sharing similar space and resource use. As the potential for competition between these three carnivores is high, understanding differences in habitat use and the effect of these potential competitors on habitat selection of ocelots is essential to conservation. Our objective was to compare habitat selection between species and examine if ocelots avoided areas used by competitors at broad and fine scales. We captured and collared 8 ocelots, 13 bobcats, and 5 coyotes on the East Foundation’s El Sauz Ranch and the Yturria San Francisco Ranch in South Texas, USA from 2017 to 2021. We compared 2nd (position of home range) and 3rd (use within the home range) order selection across species and examined whether ocelots avoided areas categorized as high probability of use by bobcats and coyotes across both orders of selection. We found a preference for heterogeneous landscapes by bobcats and coyotes while ocelots were strongly tied to woody cover across both orders. At the 2nd order, ocelots selected areas with higher probability of use by bobcats and showed no response to higher probability of use by coyotes, suggesting ocelots did not avoid either species. However, at the 3rd order, ocelots avoided areas used by coyotes. Ocelots selected for areas of use by bobcats at the 2nd order and 3rd order. Results suggest that at the broader scale, placement of the home range is not affected by the presence of sympatric carnivores, however, at a finer scale, ocelots are avoiding coyotes but not bobcats. Our study emphasizes the importance of woody and herbaceous cover at the broad scale and dense vegetation at the finer scale to sustain ocelots. In addition, we show differing patterns of interspecific avoidance by ocelots across species and scales.

Increased importance of cool-water fish at high latitudes emerges from individual-level responses to warming.

High latitude ecosystems are experiencing the most rapid warming on earth, expected to trigger a diverse array of ecological responses. Climate warming affects the ecophysiology of fish, and fish close to the cold end of their thermal distribution are expected to increase somatic growth from increased temperatures and a prolonged growth season, which in turn affects maturation schedules, reproduction, and survival, boosting population growth. Accordingly, fish species living in ecosystems close to their northern range edge should increase in relative abundance and importance, and possibly displace cold-water adapted species. We aim to document whether and how population-level effects of warming are mediated by individual-level responses to increased temperatures, shift community structure, and composition in high latitude ecosystems. We studied 11 cool-water adapted perch populations in communities dominated by cold-water adapted species (whitefish, burbot, and charr) to investigate changes in the relative importance of the cool-water perch during the last 30 years of rapid warming in high latitude lakes. In addition, we studied the individual-level responses to warming to clarify the potential mechanisms underlying the population effects. Our long-term series (1991-2020) reveal a marked increase in numerical importance of the cool-water fish species, perch, in ten out of eleven populations, and in most fish communities perch is now dominant. Moreover, we show that climate warming affects population-level processes via direct and indirect temperature effects on individuals. Specifically, the increase in abundance arises from increased recruitment, faster juvenile growth, and ensuing earlier maturation, all boosted by climate warming. The speed and magnitude of the response to warming in these high latitude fish communities strongly suggest that cold-water fish will be displaced by fish adapted to warmer water. Consequently, management should focus on climate adaptation limiting future introductions and invasions of cool-water fish and mitigating harvesting pressure on cold-water fish.

The effects of temperature and salinity on the blood chemistry and survival of juvenile Atlantic tarpon Megalops atlanticus.

Atlantic tarpon Megalops atlanticus are highly migratory sportfish that support recreational fisheries throughout their range. In US waters, juveniles can be found in coastal and estuarine habitats along the Gulf of Mexico and Atlantic seaboard, with temperature limiting their northern latitudinal distribution. Juveniles may overwinter in these areas during the first several years of life. Low temperatures are known to cause mortality in adults, but the challenges of temperature are less understood for juveniles. Furthermore, salinity, which can change dramatically in these habitats, may have a synergistic effect with temperature. To examine the physiological effects of temperature and salinity on juvenile tarpon, wild fish were acclimated to a range of conditions that potentially occur in the northern range of their estuarine habitats. The haematology of juvenile tarpon was examined in two salinity (≤2 and ≥30 ppt) and temperature (15 and 25°C) treatments, followed by a low-temperature tolerance test. After 2 weeks in treatment conditions, blood samples were analysed for haematocrit, pH, red blood cell concentration, haemoglobin content and plasma osmolality. Increased plasma osmolality was observed in fish at low temperature (15°C compared to 25°C) and at high salinity (≥30 ppt compared to ≤2 ppt). Blood pH was increased at 15°C compared to 25°C, with the highest pH at 15°C and low salinity. Haemoglobin, haematocrit and red blood cell concentration were higher at 25°C than 15°C, with haemoglobin lowest at 15°C and low salinity. For the low-temperature tolerance test, all fish were acclimated to 15°C for 2 weeks, then transferred to separate tanks where temperature was gradually decreased at 0.9 ± 0.1°C/h until fish lost equilibrium. Fish at low salinity lost equilibrium more rapidly (1 ppt, 12.65 ± 0.46°C) than fish at high salinity (30 ppt, 11.26 ± 0.14°C). The results indicate juvenile tarpon are susceptible to low temperature, which is exacerbated by low salinity, findings useful in the assessment of juvenile tarpon overwintering habitat.

Using mechanistic insights to predict the climate‐induced expansion of a key aquatic predator

AbstractAmeliorating the impacts of climate change on communities requires understanding the mechanisms of change and applying them to predict future responses. One way to prioritize efforts is to identify biotic multipliers, which are species that are sensitive to climate change and disproportionately alter communities. We first evaluate the mechanisms underlying the occupancy dynamics of marbled salamanders, a key predator in temporary ponds in the eastern United States We use long‐term data to evaluate four mechanistic hypotheses proposed to explain occupancy patterns, including autumn flooding, overwintering predation, freezing, and winterkill from oxygen depletion. Results suggest that winterkill and fall flooding best explain marbled salamander occupancy patterns. A field introduction experiment supports the importance of winterkill via hypoxia rather than freezing in determining overwinter survival and rejects dispersal limitation as a mechanism preventing establishment. We build climate‐based correlative models that describe salamander occupancy across ponds and years at two latitudinally divergent sites, a southern and middle site, with and without field‐collected habitat characteristics. Correlative models with climate and habitat variation described occupancy patterns better than climate‐only models for each site, but poorly predicted occupancy patterns at the site not used for model development. We next built hybrid mechanistic metapopulation occupancy models that incorporated flooding and winterkill mechanisms. Although hybrid models did not describe observed site‐specific occupancy dynamics better than correlative models, they better predicted the other site's dynamics, revealing a performance trade‐off between model types. Under future climate scenarios, models predict an increased occupancy of marbled salamanders, especially at the middle site, and expansion at a northern site beyond the northern range boundary. Evidence for the climate sensitivity of marbled salamanders combined with their disproportionate ecological impacts suggests that they might act as biotic multipliers of climate change in temporary ponds. More generally, we predict that top aquatic vertebrate predators will expand into temperate‐boreal lakes as climate change reduces winterkill worldwide. Predaceous species with life histories sensitive to winter temperatures provide good candidates for identifying additional biotic multipliers. Building models that include biological mechanisms for key species such as biotic multipliers could better predict broad changes in communities and design effective conservation actions.

Similar growth responses to climatic variations in Norway spruce (Picea abies) and European beech (Fagus sylvatica) at the northern range limit of beech

In south-east Norway, in the hemiboreal vegetation zone, beech reaches its northern distribution limit and typically occupies the same type of sites as spruce. Under future climate change, this area is projected to fall within the temperate zone and beech to increase its distribution towards the north at the expense of spruce. However, such forecasts are based on very broad scale estimates and the knowledge of climatic adaptation and the competitive potential of the beech and spruce populations at these latitudes is scarce. Here, we use a dendrochronological approach to study the growth performance of neighbouring spruce and beech trees to climate variability over a period of 70 years. The two species responded quite similarly to variations in climate in the study area. Both showed increased incremental growth in response to high precipitation both in the previous and present year June, indicating that water is a limiting resource. In addition, beech showed a negative response to high temperatures in previous July and August, which is probably connected with growth reductions due to masting. Overall, spruce and beech in the hemiboreal zone show comparable responses to climatic variations as in the temperate zone. Due to the different drought-handling strategies of the two species, we suggest that the intensity of summer droughts and the variability between years are likely factors that would be decisive for which of them that will be more successful under future climatic conditions.

The Chirostyloidea of the Northeastern Pacific: Host Associations, Range Extensions and a New Species (Decapoda: Anomura).

Four species of chirostyloid squat lobsters, including a new species and a range extension are reported herein from California. Uroptychus nicoleae sp.nov. was collected on a black coral, Lillipathes sp. off San Clemente Island. It is characterized by a rostrum bearing 1 or 2 lateral teeth, the carapace having 5 lateral spines and a belt of 15 spinules on the anterior dorsal surface, and the dactyls of pereopods 2-5 are curved and bearing a continuous row of 6-8 teeth. The new species is morphologically similar to U. bellus of the southwestern Pacific. The color in life is red and pink. Uroptychus occidentalis is reported for the first time off California. The chirostyloids Sternostylus iaspis and S. perarmatus, which also occur off California, are shown in video still images from a remotely operated vehicle. They inhabit antipatharians and soft corals (Primnoidae) and are easily distinguished from species of Uroptychus by their elongate chelipeds and spinose carapaces. We provide northern range extensions for Uroptychus bellus, Sternostylus defensus and Heteroptychus galapagos collected off Costa Rica.

Female ticks (Ixodes scapularis) infected with Borrelia burgdorferi have increased overwintering survival, with implications for tick population growth.

The tick, Ixodes scapularis, vectors pathogens such as Borrelia burgdorferi, the bacterium that causes Lyme disease. Over the last few decades I. scapularis has expanded its range, introducing a novel health threat into these areas. Warming temperatures appear to be one cause of its range expansion to the north. However, other factors are also involved. We show that unfed adult female ticks infected with B. burgdorferi have greater overwintering survival than uninfected female ticks. Locally collected adult female ticks were placed in individual microcosms and allowed to overwinter in both forest and dune grass environments. In the spring we collected the ticks and tested both dead and living ticks for B. burgdorferi DNA. Infected ticks had greater overwintering survival compared with uninfected ticks every winter for three consecutive winters in both forest and dune grass environments. We discuss the most plausible explanations for this result. The increased winter survival of adult female ticks could enhance tick population growth. Our results suggest that, in addition to climate change, B. burgdorferi infection itself may be promoting the northern range expansion of I. scapularis. Our study highlights how pathogens could work synergistically with climate change to promote host range expansion.

Range extensions for <i>Alopoglossus vallensis</i> (Squamata: Alopoglossidae) in the Central Andes of Colombia

The lizard Alopoglossus vallensis (family Alopoglossidae) has been historically recorded in the Cauca River Valley and the western Andes (departments of Cauca and Valle del Cauca) of Colombia. Based on a review of specimens in biological collections, we report northern and southern range extensions for the species, including the first records from the departments of Antioquia, Caldas, Quindío, and Risaralda in the Central Andes of Colombia. These new records also expand the known elevational range and climatic tolerances of A. vallensis.

Variation in Leaf Functional and Plant Defense Traits of Introduced Eucalyptus Species across Environmental Gradients in Their New Range in Southern China

Due to the rapid development of China’s economy, the demand for wood is steadily increasing. Eucalyptus species have been introduced in large quantities because of their fast growth, strong adaptability, and wide utility. To understand the phenological changes in introduced Eucalyptus in its new range, we carried out a field investigation to examine leaf functional and chemical defense traits of three introduced species (E. saligna, E. grandis and E. robusta) over latitudinal and altitudinal gradients in southern China. We sampled multiple stands of each species, and measured the leaf physical characteristics (e.g., leaf width, leaf thickness, and specific leaf area [SLA]), leaf nitrogen (N) and phosphorus (P) content, and phenolic compounds. We found that many functional traits (e.g., leaf size and thickness) decreased at lower latitudes, especially in E. grandis, possibly to reduce heat and water loss under higher temperatures. In E. grandis, we found that leaf P was lower at higher latitudes and altitude, and phenolics increased with elevation, while in E. robusta, both leaf N and P decreased with altitude. These findings suggested that both species were more conservative in resource allocation, with E. grandis possessing enhanced chemical defenses in response to the conditions experienced at higher elevations. In addition, we found the tree populations at the northern range limit of E. robusta had lower SLA, suggesting a more conservative growth strategy, In contrast, small populations in the northern part of the ranges of E. grandis had higher SLA, indicating range expansion at the edge of the species’ geographic distribution. Overall, it is particularly important to consider intraspecific trait differences across wide geographic areas when studying the spread of invasive species in the new range.

Euonymus latifolius im Böhmischen Massiv

Abstract Euonymus latifolius in the Bohemian Massif – In the present study, scattered and mainly previously unpublished distribution data of Euonymus latifolius for the Bohemian Massif are aggregated and presented in tabular and graphical form. In Lower Austria, the otherwise pre- to perialpine distribution pattern extends northwards to the area of the Bohemian Massif, becomes isolated and represents the European northern range edge of autochthonous occurrences with an exposed range outpost in the Lower Austrian Freiwald region. So far there is evidence from 10 quadrants. Although siliceous growth sites are also colonized, the ecological assemblage remains species-typical and includes deciduous forests, but also copses. The discussion is mainly devoted to the topics of floristic status, cultivation and dispersal ecology. Contradictions in the reference material concerning range and status data are pointed out.