Changes of adenine nucleotide and orthophosphate concentrations in buds of deciduous trees during spring reactivation

Summary Concentrations of AMP, ADP, ATP, and inorganic phosphate (Pi) were determined in buds of five deciduous tree species (Acer pseudoplatanus, Alnus glutinosa, Fagus sylvatica, Fraxinus excelsior, Quercus robur) during spring reactivation from February to the middle of May. In closed buds of diffuse-porous wood trees (Acer, Alnus, Fagus), the content of adenine nucleotides (AdN) increased temporarily between the middle of February and the middle of March. The main increase of AdN concentration appeared either when buds became swollen (Fraxinus, Fagus, Quercus), or at the time of bud-break (Acer, Alnus). Pi content in general decreased during the course of reactivation. It was almost zero in buds of Quercus at bud-break and afterwards, but in Fraxinus Pi concentration rose when bud-break took place. The extremely low AdN content in Quercus buds is contrasted by a steep increase in AdN content in Fraxinus following bud-break. The decrease of AdN content in emerging leaves of Quercus and Fagus could be related to the high age of these trees.Abbreviations AdN adenine nucleotide(s) - DTT dithiothreitol - EDTA ethylenediaminetetraacetic acid - PEP phosphoenolpyruvate - Pi orthophosphate Supported by Deutsche Forschungsgemeinschaft and by Bundesministerium für Forschung und Technologie, Federal Republic of Germany.     

Environmental drivers interactively affect individual tree growth across temperate European forests

Forecasting the growth of tree species to future environmental changes requires a better understanding of its determinants. Tree growth is known to respond to global‐change drivers such as climate change or atmospheric deposition, as well as to local land‐use drivers such as forest management. Yet, large geographical scale studies examining interactive growth responses to multiple global‐change drivers are relatively scarce and rarely consider management effects. Here, we assessed the interactive effects of three global‐change drivers (temperature, precipitation and nitrogen deposition) on individual tree growth of three study species (Quercus robur/petraea, Fagus sylvatica and Fraxinus excelsior). We sampled trees along spatial environmental gradients across Europe and accounted for the effects of management for Quercus. We collected increment cores from 267 trees distributed over 151 plots in 19 forest regions and characterized their neighbouring environment to take into account potentially confounding factors such as tree size, competition, soil conditions and elevation. We demonstrate that growth responds interactively to global‐change drivers, with species‐specific sensitivities to the combined factors. Simultaneously high levels of precipitation and deposition benefited Fraxinus, but negatively affected Quercus’ growth, highlighting species‐specific interactive tree growth responses to combined drivers. For Fagus, a stronger growth response to higher temperatures was found when precipitation was also higher, illustrating the potential negative effects of drought stress under warming for this species. Furthermore, we show that past forest management can modulate the effects of changing temperatures on Quercus’ growth; individuals in plots with a coppicing history showed stronger growth responses to higher temperatures. Overall, our findings highlight how tree growth can be interactively determined by global‐change drivers, and how these growth responses might be modulated by past forest management. By showing future growth changes for scenarios of environmental change, we stress the importance of considering multiple drivers, including past management and their interactions, when predicting tree growth.     

Pulsed resource availability changes dietary niche breadth and partitioning between generalist rodent consumers

Identifying the mechanisms that structure niche breadth and overlap between species is important for determining how species interact and assessing their functional role in an ecosystem. Without manipulative experiments, assessing the role of foraging ecology and interspecific competition in structuring diet is challenging. Systems with regular pulses of resources act as a natural experiment to investigate the factors that influence the dietary niches of consumers. We used natural pulses of mast‐fruiting of American beech (Fagus grandifolia) to test whether optimal foraging or competition structure the dietary niche breadth and overlap between two congener rodent species (Peromyscus leucopus and P. maniculatus), both of which are generalist consumers. We reconstructed diets seasonally over a 2‐year period using stable isotope analysis (δ¹³C, δ¹⁵N) of hair and of potential dietary items and measured niche dynamics using standard ellipse area calculated within a Bayesian framework. Changes in niche breadth were generally consistent with predictions of optimal foraging theory, with both species consuming more beechnuts (a high‐quality food resource) and having a narrower niche breadth during masting seasons compared to nonmasting seasons when dietary niches expanded and more fungi (a low‐quality food source) were consumed. In contrast, changes in dietary niche overlap were consistent with competition theory, with higher diet overlap during masting seasons than during nonmasting seasons. Overall, dietary niche dynamics were closely tied to beech masting, underscoring that food availability influences competition. Diet plasticity and niche partitioning between the two Peromyscus species may reflect differences in foraging strategies, thereby reducing competition when food availability is low. Such dietary shifts may have important implications for changes in ecosystem function, including the dispersal of fungal spores.     

Deciduous and semi-deciduous oak forests (<Emphasis Type="Italic">Quercus robur,Q. petraea</Emphasis> and <Emphasis Type="Italic">Q. pyrenaica</Emphasis>) floristic composition in the Northwest Iberian Peninsula

Oak forests in the Northwest Iberian Peninsula represent climax communities with a high floristic diversity of vascular plants. This study presents data from 189 botanical samples randomly collected in stands of deciduous and semi-deciduous oak as Quercus robur (98), Q. petraea (50) and Q. pyrenaica (41). Within these stands, 187 species or subspecies were identified, in addition to 20 genera and 68 families, all of them present in forests of Quercus robur. A total of 126 species occur in more than five relevés. The largest number of species corresponds to Poaceae (22), Fabaceae (19) and Rosaceae (14). The biological spectrum is dominated by hemicryptophytes, with mainly Atlantic and Sub-Atlantic floristic elements. The distribution of the stands has been studied by using Two-Way Indicator Species Analysis, obtaining like pseudo-species, with shrubby and arborea form, the following ones: Fagus sylvatica, Castanea sativa, Sorbus aucuparia, Corylus avellana, Crataegus monogyna, Pyrus cordata, Erica arborea, Frangula alnus and Cytisus scoparius.     

Vegetation structure and diversity of an ancient temperate deciduous forest in SW Denmark

Bolderslev Skov (113 ha) is the largest contiguous ancient forest remnant in Denmark. The forest has been preserved since 1998 as a strict non-intervention forest reserve. We studied vegetation structure, floristic gradients, and diversity of the forest in 50 plots of 100 m² placed according to a restricted random sampling design. Dominant tree species were Fagus sylvatica, Fraxinus excelsior, Tilia cordata and Quercus robur, which in most parts of the forest form a mixed canopy. Most stands appeared to be of moderate age, 55-80 years old, and large old trees were rare. pH in association with light and thickness of the litter layer were the most important factors in explaining floristic gradients in the forest. Soil moisture (dry to mesic) was not strongly correlated with DCA axes for neither tree nor field layer, but had a significant effect on the distribution of a number of herb species. Forest structure was not important in explaining species distributions. Field layer species richness showed a positive relationship with the pH-gradient. At the scale of 1m² plots we also found a highly significant negative relationship between field layer species richness and the plot-wise Ellenberg indicator value for nitrogen availability. Structure of the tree layer had little effect on field layer species richness. The mixed composition, long continuity, and presence of a high proportion of the regional species pool assigns a high conservation value to Bolderslev Skov and makes it an important site for future studies of the dynamic properties, niche preferences, and inter-specific competition of temperate deciduous forest species. This revised version was published online in June 2006 with corrections to the Cover Date.     

The trophic structure of bark-living oribatid mite communities analysed with stable isotopes (15N, 13C) indicates strong niche differentiation

The aim of the present study was to identify food sources of bark-living oribatid mites to investigate if trophic niche differentiation contributes to the diversity of bark living Oribatida. We measured the natural variation in stable isotope ratios (¹⁵N/¹⁴N, ¹³C/¹²C) in oribatid mites from the bark of oak (Quercus robur), beech (Fagus sylvatica), spruce (Picea abies) and pine (Pinus sylvestris) trees and their potential food sources, i.e., the covering vegetation of the bark (bryophytes, lichens, algae, fungi). As a baseline for calibration the stable isotope signatures of the bark of the four tree species were measured and set to zero. Oribatid mite stable isotope ratios spanned over a range of about 13 δ units for ¹⁵N and about 7 δ units for ¹³C suggesting that they span over about three trophic levels. Different stable isotope signatures indicate that bark living oribatid mites feed on different food sources, i.e., occupy distinct trophic niches. After calibration stable isotope signatures of respective oribatid mite species of the four tree species were similar indicating close association of oribatid mites with the corticolous cover as food source. Overall, the results support the hypothesis that trophic niche differentiation of bark living oribatid mites contributes to the high diversity of the group.     

The effect of climate conditions on inter-annual flowering variability monitored by pollen traps below the canopy in Draved Forest, Denmark

Since 1967 annual pollen deposition has been monitored in the semi-natural mixed deciduous woodland Draved Forest by the Geological Survey of Denmark. In this paper, we analyse the variability in pollen accumulation rates for the eight most common deciduous trees, and their relationships to monthly temperature and precipitation. High summer temperatures in the year before flowering have a positive effect on pollen deposition for several species. A positive correlation between temperatures during the flowering season and pollen accumulation rates is found for Fagus sylvatica, Quercus robur, Fraxinus excelsior and Corylus avellana. The amount of precipitation can have both positive and negative effects on pollen accumulation, depending on species and on time of year. Linear modelling showed that combinations of monthly climate parameters could explain between 10 and 80% of the variation observed in different species. There were marked differences in the time series of pollen accumulation and pollen/climate relationships for some species between traps within the forest related to the location of trees near the traps. This underlines the importance of using multiple traps in a region for this type of study. Time series analyses were used to test for cyclicity in pollen accumulation rates, which could be caused by resource limitations or internal biological factors. No significant autocorrelations were found, although Alnus glutinosa showed a tendency towards 3-year cyclicity. These results indicate that, with the possible exception of Alnus glutinosa, temperature and precipitation are the main factors controlling the annual variability in pollen deposition of the trees in Draved Forest.     

Nurse Trees as a Forest Restoration Tool for Mixed Plantations: Effects on Competing Vegetation and Performance in Target Tree Species

Multi‐species mixed plantations can be designed to meet social, economic, and environmental objectives during forest restoration. This paper reports results from an experiment in southern Sweden concerning the influence of three different fast growing nurse tree species on the cover of herbaceous vegetation and on the performance of several target tree species. After 10 years, the nurse trees had reduced the competing herbaceous vegetation but the effect was weak and it may take more than a decade to achieve effective vegetation control. The nurse tree species Betula pendula and Larix x eurolepis did improve stem form in some target tree species, but had a minor effect on survival and growth. The open conditions before crown closure of nurse trees strongly influence seedling performance and so delayed planting of target tree species may provide a means to avoid those conditions. Survival and growth differed greatly among the tree species. Besides the two nurse tree species mentioned above, high survival was found in Picea abies and Quercus robur and intermediate survival in Fagus sylvatica, Tilia cordata, and in the N‐fixing nurse tree Alnus glutinosa. Survival was low in the target tree species Fraxinus excelsior L. and Prunus avium. For restoration practitioners, our results illustrate the potential of using nurse trees for rapidly building a new forest structure and simultaneously increase productivity, which might be a cost‐effective strategy for forest restoration.     

Hierarchical analysis of the relationship between spatial distribution and abundance of epiphytic lichens (Mt. Olympos-Greece)

The relationship between distribution and abundance of epiphytic lichens on five different substrates (Fagus sylvatica, Pinus nigra, Quercus coccifera, Pinus heldreichii and Quercus pubescens) has been studied. For the first three substrates the above relationship has been studied hierarchically. It was concluded that this relationship is partly represented by the core-satellite distribution. This abundance-distribution pattern could probably be explained by more than one hypothesis and it is probably related with the life strategies of lichen species.     

6000 years of forest dynamics in Suserup Skov, a seminatural Danish woodland

• 1 The history of a forest stand over the last 6000 years has been reconstructed by studying pollen, macrofossils and charcoal from a small, wet hollow in Suserup Skov on the island of Sjælland in eastern Denmark.
• 2 The earliest recorded forest was Tilia‐dominated but contained an intimate mixture of many different tree species that included Acer campestre, A. platanoides, Alnus glutinosa, Betula pubescens, Corylus avellana, Frangula alnus, Fraxinus excelsior, Malus sylvestris, Populus tremula, Pinus sylvestris, Quercus robur, Q. petraea, Salix spp., Sorbus aucuparia, Tilia cordata and T. platyphyllos. The preserved fruits of T. platyphyllos confirm its hitherto doubtful status as a native member of the Danish flora.
• 3 The present‐day woodland developed after a period of intensive anthropogenic disturbance between ≈ 600 bc and ad 900, during which time open canopy conditions prevailed at Suserup. Fagus sylvatica and Fraxinus excelsior are the dominant trees at present, together with some Quercus robur and Ulmus glabra. 4 Charcoal was present in the sediments from most time periods except at the Ulmus decline. In the last 1000 years of the sequence — the period of Fagus dominance — charcoal counts were consistently low.
• 5 Pinus sylvestris was a natural component of this primarily deciduous forest, and the last macrofossil find dates from c. ad 900. Macrofossil Pinus cone scales recorded c. ad 1800 originate from planted individuals. Prior to Fagus dominance, the forest had an open structure partly caused by frequent, low‐intensity fires associated with the presence of Pinus sylvestris.
• 6 The replacement of Tilia by Fagus in this forest was catalysed by human activity. If the forest had not been so disturbed, the rich diversity of trees would most probably have persisted up to the present time, with only a moderate‐sized Fagus population.

     

Contrasting climate niches among co‐occurring subdominant forbs of the sagebrush steppe

Aim

Abiotic conditions are key components that determine the distribution of species. However, co‐occurring species can respond differently to the same factors, and determining which climate components are most predictive of geographic distributions is important for understanding community response to climate change. Here, we estimate and compare climate niches of ten subdominant, herbaceous forb species common in sagebrush steppe systems, asking how niches differ among co‐occurring species and whether more closely related species exhibit higher niche overlap.

Location

Western United States.

Methods

We used herbarium records and ecological niche modelling to estimate area of occupancy, niche breadth and overlap, and describe characteristics of suitable climate. We compared mean values and variability in summer precipitation and minimum temperatures at occurrence locations among species, plant families, and growth forms, and related estimated phylogenetic distances to niche overlap.

Results

Species varied in the size and spatial distribution of suitable climate and in niche breadth. Species also differed in the variables contributing to their suitable climate and in mean values, spatial variation and interannual variation in highly predictive climate variables. Only two of ten species shared comparable climate niches. We found family‐level differences associated with variation in summer precipitation and minimum temperatures, as well as in mean minimum temperatures. Growth forms differed in their association with variability in summer precipitation and minimum temperatures. We found no relationship between phylogenetic distance and niche overlap among our species.

Main conclusions

We identified contrasting climate niches for ten Great Basin understorey forbs, including differences in both mean values and climate variability. These estimates can guide species selection for restoration by identifying species with a high tolerance for climate variability and large climatic niches. They can also help conservationists to understand which species may be least tolerant of climate variability, and potentially most vulnerable to climate change.

     

Feeding ecology and seasonal diet overlap between Stellifer brasiliensis and Stellifer stellifer in a tropical estuarine ecocline

Seasonal freshwater discharge was important for defining habitat utilization by different ontogenetic phases of Stellifer brasiliensis and Stellifer stellifer along the estuarine ecocline. The middle estuary was important as a nursery and feeding ground for young‐of‐the‐year, and a feeding ground for sub‐adults and adults of both species. These species are zoobenthivorous, but during their life cycle and between different habitats and seasons, their trophic guild can change to opportunist and zooplanktivore. During the late rainy season in the lower estuary, all phases of both species, except juveniles of S. brasiliensis and adults of S. stellifer, showed a niche overlap indicating similarity in prey utilization. The diet composition was qualitatively similar, showing an evident niche overlap of intra and interspecific competition among the Stellifer spp. Although the niches of these species appeared to significantly overlap, some resource partitioning patterns were apparent. The niche overlap was significantly reduced due to the seasonal difference in habitat use and prey consumption along the ecocline of the estuary by different ontogenetic phases. The ingestion of blue nylon fragments by both species was observed and quantified.     

Investigating the relationship between climate,stand age,and temporal trends in masting behavior of European forest trees

Masting—temporally variable seed production with high spatial synchrony—is a pervasive strategy in wind‐pollinated trees that is hypothesized to be vulnerable to climate change due to its correlation with variability in abiotic conditions. Recent work suggests that aging may also have strong effects on seed production patterns of trees, but this potential confounding factor has not been considered in previous times series analysis of climate change effects. Using a 54 year dataset for seven dominant species in 17 forests across Poland, we used the proportion of seed‐producing trees (PST) to contrast the predictions of the climate change and aging hypotheses in Abies alba, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, Quercus petraea, and Quercus robur. Our results show that in all species, PST increased over time and that this change correlated most strongly with stand age, while the standardized precipitation–evapotranspiration index, a measure of drought, contributed to temporal trends in PST of F. sylvatica and Q. robur. Temporal variability of PST also increased over time in all species except P. sylvestris, while trends in temporal autocorrelation and among‐stand synchrony reflect species‐specific masting strategies. Our results suggest a pivotal role of plant ontogeny in driving not only the extent but also variability and synchrony of reproduction in temperate forest trees. In a time of increasing forest regrowth in Europe, we therefore call for increased attention to demographic effects such as aging on plant reproductive behavior, particularly in studies examining global change effects using long‐term time series data.     

How much does climate change threaten European forest tree species distributions?

Although numerous species distribution models have been developed, most were based on insufficient distribution data or used older climate change scenarios. We aimed to quantify changes in projected ranges and threat level by the years 2061–2080, for 12 European forest tree species under three climate change scenarios. We combined tree distribution data from the Global Biodiversity Information Facility, EUFORGEN, and forest inventories, and we developed species distribution models using MaxEnt and 19 bioclimatic variables. Models were developed for three climate change scenarios—optimistic (RCP2.6), moderate (RCP4.5), and pessimistic (RPC8.5)—using three General Circulation Models, for the period 2061–2080. Our study revealed different responses of tree species to projected climate change. The species may be divided into three groups: “winners”—mostly late‐successional species: Abies alba, Fagus sylvatica, Fraxinus excelsior, Quercus robur, and Quercus petraea; “losers”—mostly pioneer species: Betula pendula, Larix decidua, Picea abies, and Pinus sylvestris; and alien species—Pseudotsuga menziesii, Quercus rubra, and Robinia pseudoacacia, which may be also considered as “winners.” Assuming limited migration, most of the species studied would face a significant decrease in suitable habitat area. The threat level was highest for species that currently have the northernmost distribution centers. Ecological consequences of the projected range contractions would be serious for both forest management and nature conservation.     

Species richness and substrate specificity of lignicolous fungi in the canopy of a temperate,mixed deciduous forest

In the more than twenty years in which long-term canopy research has been conducted, mycology has been largely disregarded. Our studies using a construction crane to gain access to the canopy of a forest in Leipzig, Germany are the first long term investigations assessing the diversity and ecology of wood-decaying fungi in a canopy. Thirty-seven individuals of nine different tree species with a large amount of dead wood were selected. Sampling focussed on the four most prominent tree species Acer pseudoplatanus, Fraxinus excelsior, Quercus robur and Tilia cordata. In the years 2002 and 2003 dead wood was collected in different canopy strata. Dead branches were removed and stored for two weeks in open boxes with high humidity to allow growth of fructifications in the laboratory. 118 different taxa were identified (108 species, 77 genera). Corticioid fungi (e.g., of Corticiaceae, Stereaceae, Hymenochaetaceae) dominated the fungal composition with 37 species, pyrenomycetes were present with 18 species. Agaric fungi (Agaricales and Cortinariales) were scarce. Species with minute basidiomes dominated the fungal composition of this systematic group. Agarics with larger sporomes were found only once and were restricted to strongly decayed branches in shaded canopy areas. Concerning species richness and fungal composition the four tree species mentioned above differed remarkably. As expected, many fungi that grew on bark or slightly decayed wood showed a distinct host and substratum specifity. It is noteworthy that fungi which are purportedly to be non-specific were found on single tree species only.     

Carbon isotope discrimination and wood anatomy variations in mixed stands of Quercus robur and Quercus petraea

The two most common oak species in western Europe, Quercus robur and Quercus petraea, display different ecological behaviours, particularly with respect to their responses to drought. The ecophysiological basis of this niche difference is not understood well. Here we test the hypothesis that these two species present distinct water use efficiencies (WUEs), using the carbon isotope discrimination approach. Leaves and 13 dated ring sequences were sampled in 10 pairs of adult trees growing side by side. Carbon isotope composition was measured on cellulose extracts. In addition, relationships between carbon isotope discrimination and wood anatomy were assessed at the tree level. Quercus robur displayed a 1·0‰ larger isotopic discrimination than Q. petraea, and therefore a lower intrinsic WUE (?13%). This interspecific difference of isotopic discrimination was quite stable with time and independent of tree radial growth and climate fluctuations. A strong positive correlation was observed between average tree values of earlywood vessel surface area and ¹³C isotopic discrimination. This correlation was even higher with ¹³C of the 1976 dry year (r = 0·86). These observations led to the hypothesis that hydraulic properties of xylem could exert a constraint on leaf gas exchange, resulting in a larger WUE for individuals with smaller vessel cross‐section area.     

Evolution of the climatic niche in scaly tree ferns (Cyatheaceae,Polypodiopsida)

Although climatic niche conservatism has been assumed by a large number of studies focused on climatic niche evolution, there are examples of climatic niche diversification and adaptation to changing climates. In this article, we reconstruct a climatic niche of scaly tree ferns (Cyatheaceae) using a rigorous analytical procedure which combines climatic niche modelling with reconstruction of continuous characters given a phylogenetic hypothesis. To estimate the limits to climatic niches of species, we used climate envelope modelling and ordination. Ancestral climatic niches of species were reconstructed by maximum likelihood and least‐squares analyses. We observed a trend towards niche conservatism with occasional events of niche transformations in scaly tree ferns. We discuss the implications of our study with respect to the potential and limitations for applications of niche modelling to evolutionary studies. We suggest that future studies of evolution of climatic niches could be considerably improved by employing approaches enabling reconstruction of continuous response to climatic gradients. Further progress may also be achieved by exploring models of character evolution other than the Brownian motion model. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 1–19.     

Micronutrient levels in some temperate European tree species: a comparative field study

Micronutrient concentrations in foliage and stemwood (including bark) of six European tree species (Betula pendula Roth., Quercus robur L., Fraxinus excelsior L., Fagus sylvatica L., Tilia cordata Mill. and Picea abies (L.) Karst.) planted on the same type of soil at six sites in three different countries were studied. Micronutrient concentrations in foliage were considerably higher than in stemwood for all elements and species studied, except for Fe in spruce. Interspecies comparisons revealed significant differences in concentrations both in foliar and stemwood biomass, as well as in stemwood:foliage nutrient ratios. Lime foliage showed a considerably higher concentration of B than all other species, while the stemwood concentration of this element was highest in ash. Mn concentration in both foliar and stemwood biomass of ash was extremely low compared with concentrations in other species. Birch stemwood showed nearly double the level of Zn in other species at all sites. Zn concentrations in the birch foliage were also higher than in other species, with the exception of the Lithuanian sites, which showed lower EDTA-extractable Zn concentrations in the soils. The concentration of Cu was lowest in spruce foliage, while Cu concentrations in stemwood were similar in all species. It was concluded that species-related differences in microelement nutrition must be taken into account when evaluating the nutrient status of common European forest tree species, and when using them as bio-indicators of the effects of environmental pollution.     

Using ecological niche modelling to evaluate niche stability in deep time

Aim To investigate relative niche stability in species responses to various types of environmental pressure (biotic and abiotic) on geological time‐scales using the fossil record. Location The case study focuses on Late Ordovician articulate brachiopods of the Cincinnati Arch in eastern North America. Methods Species niches were modelled for a suite of fossil brachiopod species based on five environmental variables inferred from sedimentary parameters using GARP and Maxent . Niche stability was assessed by comparison of (1) the degree of overlap of species distribution models developed for a time‐slice and those generated by projecting niche models of the previous time‐slice onto environmental layers of a second time‐slice using GARP and Maxent , (2) Schoener’s D statistic, and (3) the similarity of the contribution of each environmental parameter within Maxent niche models between adjacent time‐slices. Results Late Ordovician brachiopod species conserved their niches with high fidelity during intervals of gradual environmental change but responded to inter‐basinal species invasions through niche evolution. Both native and invasive species exhibited similar levels of niche evolution in the invasion and post‐invasion intervals. Niche evolution was related mostly to decreased variance within the former ecological niche parameters rather than to shifts to new ecospace. Main conclusions Although the species examined exhibited morphological stasis during the study interval, high levels of niche conservatism were observed only during intervals of gradual environmental change. Rapid environmental change, notably inter‐basinal species invasions, resulted in high levels of niche evolution among the focal taxa. Both native and invasive species responded with similar levels of niche evolution during the invasion interval and subsequent environmental reorganization. The assumption of complete niche conservatism frequently employed in ecological niche modelling (ENM) analyses to forecast or hindcast species geographical distributions is more likely to be accurate for climate change studies than for invasive species analyses over geological time‐scales.