Feeding Niche Breadth Research Articles

Conifers and non-native tree species shift trophic niches of generalist arthropod predators in Central European beech forests

BackgroundFunctional diversity is vital for forest ecosystem resilience in times of climate-induced forest diebacks. Admixing drought resistant non-native Douglas fir, as a partial replacement of climate-sensitive Norway spruce, to native beech forests in Europe appears promising for forest management, but possible consequences for associated biota and ecosystem functioning are poorly understood. To better link forest management and functional diversity of associated biota, we investigated the trophic niches (∆13C, ∆15N) of epigeic generalist predators (spiders and ground beetles) in mixed and pure stands of European beech, Norway spruce and non-native Douglas fir in north-west Germany. We assessed the multidimensional niche structure of arthropod predator communities using community-based isotopic metrics.ResultsWhilst arthropod ∆13C differed most between beech (high ∆13C) and coniferous stands (low ∆13C), ∆15N was lowest in non-native Douglas fir. Tree mixtures mitigated these effects. Further, conifers increased isotopic ranges and isotopic richness, which is linked to higher canopy openness and herb complexity. Isotopic divergence of ground beetles decreased with Douglas fir presence, and isotopic evenness of spiders in Douglas fir stands was lower in loamy sites with higher precipitation than in sandy, drier sites.ConclusionsWe conclude that tree species and particularly non-native trees alter the trophic niche structure of generalist arthropod predators. Resource use and feeding niche breadth in non-native Douglas fir and native spruce differed significantly from native beech, with more decomposer-fueled and narrower feeding niches in beech stands (∆13C, isotopic ranges and richness). Arthropod predators in non-native Douglas fir, however, had shorter (∆15N) and simplified (isotopic divergence) food chains compared to native forest stands; especially under beneficial abiotic conditions (isotopic evenness). These findings indicate potential adverse effects of Douglas fir on functional diversity of generalist arthropod predators. As tree mixtures mitigated differences between beech and conifers, mixed stands including (non-native) conifers constitute a promising compromise between economic and conservational interests.

FEEDING ECOLOGY OF A PARROT ASSEMBLAGE IN THE BRAZILIAN CERRADO

In this study, during two years, I documented the feeding habits of a parrot assemblage in response to food resources offer (abundance, nº of food species, and diversity), across a habitat mosaic in the Brazilian Cerrado. In addition, to each parrot species, I compared variations in those parameters across seasons, as well as in the feeding niche breadth. The feeding activity of every parrot species paralleled both food abundance and the number of food species available. In fact, despite fluctuations, food abundance, the number of food species, and diversity exhibited similar values through seasons, suggesting a trend for adequate food supply across the three major habitat types (palm swamp, gallery forest, and the dominant Cerrado vegetation). Excepting Orthopsittaca manilata (foraged only on Mauritia flexuosa fruit pulp), all other five species (Ara ararauna, Amazona aestiva, Alipiopsitta xanthops, Eupsittula aurea, and Diopsittaca nobilis) showed wide feeding niche breadth. Their broad diets resulted from the opportunist use of a rich collection of seasonal food species. Moreover, they presented diet association according to plant part eaten, in which parrot’s diet displayed a gradient that had an increasingly greater dominance of seeds (A. ararauna, A. aestiva, and A. aurea), to a diet composed mainly by fruit pulp and flowers (A. xanthops, and D. nobilis). The accelerated fragmentation process of the Brazilian Cerrado has been suppressing habitat types in which unpredictable and scattered food patches might be available to parrots. Thus, conservation plans should prioritize the inclusion of habitat mosaics, at least, in the form documented here. As a concern, in the smaller Cerrado remnants, food resources available may be scarce, mainly in terms of the variety and abundance year-round required by parrots.

Assassin snails (Anentome helena) as a biological model for exploring the effects of individual specialisation within generalist predators.

Quantifying feeding behaviour of generalist predators at the population and individual levels is crucial for understanding the structure and functioning of food webs. Individual predator/consumer feeding niches can be significantly narrower than that of the population across animal taxa. In such species, the population of a generalist predator becomes essentially an ensemble of specialist individuals and this often highly affects the dynamics of the prey-predator interactions. Currently, few experimental systems exist that are both easily technically manipulated in a lab and are reliable to accurately assess effects of individual specialisation within generalist predators. Here we argue that a freshwater predaceous snail, Anentome helena (also known as an ‘assassin snail’), is a convenient and reliable experimental system to study feeding of a generalist predator on multiple food types which exhibits well-pronounced specialisation of foraging individuals. Using A. helena we experimentally test: (i) how relative prey abundances in the environment affect the feeding patterns, (ii) whether the feeding patterns are consistent over the duration of the experimental period, and (iii) compare the feeding niche breadth of individuals to that of the laboratory population. By offering four different prey snail species, at a range of relative abundances, we show that there are consistent patterns in feeding. Importantly, the consumption of each prey was independent of the relative abundance at which they were present. Individual predators showed selectivity to a particular prey, i.e. the population of assassin snails seems to be formed of individuals that specialise on different prey. Our findings would contribute to the recent revision and the ongoing debate on the classification of predator species into generalists and specialists.

Sexual Dimorphism and Feeding Ecology of the Black-bellied Bunchgrass Lizard Sceloporus aeneus (Squamata: Phrynosomatidae) in Central Mexico

Morphology and resource use have a significant influence on lizard population dynamics. In this study, sexual dimorphism and feeding ecology were assessed in a population of Sceloporus aeneus from central Mexico. Sexual dimorphism was recorded, with males being larger than females in several morphological characteristics, such as jaw width, femur length, tibia length, and forearm length, but not snout–vent length (SVL) or jaw length, which were similar in both sexes. The stomach contents analysis indicated an insectivorous diet composed of 11 prey categories, of which females consumed 11 and males consumed 9. Low values of feeding niche breadth were found, as well as high overlap between sexes and seasons. For the whole population, adult preys of the family Formicidae and orders Coleoptera and Hemiptera showed the highest values of food importance and abundance. A higher volume of stomach contents was recorded during the dry season than the wet season in both females and males. Results showed a pattern of sexual dimorphism similar to that of other species of the genus Sceloporus, but different from those of other populations of the same species. Morphological variation in jaw length and width seems to be related to food resources use because, in spite of the high similarity in the diet between sexes, the volume of stomach contents was not correlated with SVL in females. These findings suggest a constant consumption of food that is subsequently invested in reproduction. Further studies analyzing morphology and diet and their effect on reproductive characteristics such as clutch size, eggs mass, and volume are needed among populations of this species. The results obtained in this research could help explain the differences and similarities previously reported on the morphology and reproductive characteristics for S. aeneus and other species of the S. scalaris group.

Broad feeding niches of capelin and sand lance may overlap those of polar cod and other native fish in the eastern Canadian Arctic

As ocean temperatures rise, sub-Arctic capelin (Mallotus villosus) and sand lance (Ammodytes spp.) have become increasingly abundant in regions of the eastern Canadian Arctic. These fish have a similar trophic role to the keystone polar cod (Boreogadus saida), potentially competing for food resources when co-occurring. To evaluate this, we calculated feeding niche breadth and overlap based on fatty acids and δ15N- and δ13C-derived trophic position and carbon source, among sub-Arctic fish and 10 Arctic fish and invertebrates within low, mid, and high latitudes of the Canadian Arctic. Diverse feeding strategies including benthic Myoxocephalus sp., anadromous and pelagic fish, led to limited feeding niche overlap among species (13% average, range 0–96%). Feeding niche overlap between capelin and sand lance from the low Arctic was generally high (36–93%); while fatty acid niches of these fish overlapped 0–21% with polar cod in the mid and high Arctic, and their isotopic niches overlapped up to 96%. Capelin and sand lance showed 3–8 times broader feeding niches than polar cod. Regarding regional variation, polar cod had similar niche breadth between regions and highly overlapping fatty acid niches. Niche variation for Myoxocephalus sp. and Gammarus spp. between low and high Arctic was likely associated with more diverse sources of primary production in the shallower, more brackish low Arctic. Although regional variation in food availability play an important role defining feeding niches, broader niches and isotopic niche overlap with polar cod indicated a potential ecological advantage for capelin and sand lance over polar cod under climate change.

Food processing does not affect energy intake in the nectar-feeding bat Anoura geoffroyi

Food processing affects the way animals behave with important implications in their ecology and community structure. Despite numerous studies of food processing by nectar-feeding bats have been done, these have been focused on species living in tropical climates, whereas the information about species inhabiting high altitude environments is scarce. Here, we investigated food processing of the nectar-feeding bat Anoura geoffroyi, a species that can be found in places above 2, 500m a.s.l. To do this, we evaluated the capacity of bats to assimilate the energy content in seven sucrose solutions ranging from 5 to 35%. We measured: 1) nightly food/energy intake, and 2) changes in body mass of seven captive individuals feeding from the different experimental solutions. Bats increased food intake nearly seven times (from 16.9±4.7 to 111.6±18.7g) when sucrose concentration decreased from 35 to 5% (wt/vol). By doing this, animals were able to obtain a constant energy intake of 101.07kJ±5.4 (mean±SD) and a mean body mass gain of 1.31g±0.1 (mean±SD). Both values were independent of sugar concentration. This response (known as compensatory feeding) may enable bats the access to many feeding sources present in their environment, increasing their feeding niche-breadth and their ability to live in cold environments.

Chaco Chachalaca (Ortalis canicollis, Wagler, 1830) feeding ecology in a gallery forest in the South Pantanal (Brazil).

Cracids are generalist frugivores, which often exploit plant food resources such as flowers and leaves, mainly when fruit production declines. The Chaco chachalaca (Ortalis canicollis) is the most abundant cracid in the Pantanal (Brazil), and particularly common in the gallery forests. However, the factors related to their occurrence in this habitat type are unclear. In this study I describe the feeding habits and feeding niche breadth fluctuations of the Chaco chachalaca in relation to food resources abundance and diversity at the Miranda river gallery forest (Southern Pantanal). I also analyzed the relationships between Chaco chachalacas feeding activity and food resources abundance. This parameter (flowers and fruits) exhibited significant seasonal differences of abundance in which flowers were plentiful at the end of the dry, while fruits were abundant during the early wet season. However, food resources diversity to Chaco chachalacas exhibited no seasonal difference. Their feeding activity paralleled the availability of food resources, so that when some items were massively available an enhanced number of Chaco chachalacas foraged in the gallery forest, particularly during the prolonged dry season when they extensively used flowers and Genipa americana fruits. In fact, the Chaco chachalaca feeding niche breadth value presented low values in this period, while high values were common in the rest of the year. The flexible diet of this cracid, potentially favors their year round presence in the gallery forest, mainly during the prolonged dry season when the propensity for famine might be high. Since the Chaco chachalaca is among the largest and most abundant canopy frugivores in the gallery forest, it may contribute to forest regeneration, an underscored role due to the impact of annual floods and meandering dynamics on tree loss.

Factors involved in prey resource partitioning in the genus Artedidraco (Notothenioidei, Artedidraconidae) from the western Ross Sea

Antarctic plunderfishes are demersal species inhabiting the continental shelf of the Ross Sea, with sympatric distributions and similar morphology. Assuming these species are potential competitors for food, we aimed to quantify food overlap among them and to test the existence of factors involved in prey resource partitioning. Dietary composition and feeding niche breadth were estimated through stomach contents analysis of some species of Artedidraco sampled in the western Ross Sea. The fish community consisted of a wide range of feeders, from specialists like A. glareobarbatus and A. shackletoni, which fed exclusively on epifaunal polychaetes, to generalists like A. loennbergi and A. skottsbergi, which fed on a variety of prey. Although all species relied exclusively on benthic prey, diet diversity and prey type largely differed from each other, both contributing to reduce prey overlap and food competition. In a few cases, relatively high food overlap was observed between species with different spatial distributions. Based on our data and on previous studies, prey resource partitioning in plunderfishes is therefore established through morphological and behavioural adaptations, either by differential development of sense organs and trophic structures or by different diet composition and spatial distribution within the shared benthic habitat.

Plant food resources exploited by Blue-and-Yellow Macaws (Ara ararauna, Linnaeus 1758) at an urban area in Central Brazil.

In this study, we described the food plants available to Blue-and-Yellow Macaws (Ara ararauna), its feeding habits and the relationship between these parameters with feeding niche breadth. We established four transects, each one 12 km long, to sample fruiting plants and the feeding habits of this macaw (monthly 40 h, of observations), at the urban areas of Três Lagoas (Mato Grosso do Sul, Brazil). During all studied months, macaws foraged for palm fruits, mainly Syagrus oleracea and Acrocomia aculeata fruit pulp, both available all year, as well as Caryocar brasiliense and Anacardium occidentale seeds, in the wet season. The year-round feeding activity of macaws suggests Três Lagoas city as an adequate feeding area. The permanent availability of plant food resources, potentially, resulted from the diverse fruiting patterns of exotic and, mainly, native plant species, which provided a variety of suitable fruit patches.

Frugivory by Toco Toucan (Ramphastos toco) inhabiting a mountain chain in the Brazilian cerrado

I describe the feeding habits of Ramphastos toco (Toco Toucan) in relation to fruit abundance and diversity in a variety of habitat types in central Brazil. I traversed transects to sample fruit production and toucans that were feeding in four habitat types: two wet (streams and river) and two dry (cerrado and deciduous forest). Fruit abundance exhibited substantial temporal and spatial variability in which dry habitats provided fruits to toucans mainly in the dry season; the same occurred in the wet habitats during the rainy season. As a result, toucans experienced similar fruit diversity between seasons, while feeding niche breadth exhibited high values all year. The variable spatial and temporal fruiting patterns reflected differences among the vegetation of the four habitat types, and floristic variations between related sites as well. The data emphasize the importance of the peculiarities of a given site within a habitat mosaic and which should be included in conservation plans for declining species.

Trophic ecology and microhabitat utilization by the Bufo gargarizans, Rana guentheri, and Rana limnocharis in southwestern China

We studied the trophic ecology and microhabitat use of the Asiatic toad, Bufo gargarizans Cantor, 1842; Guentheri frog, Rana guentheri (Boulenger, 1882); and the Ricefield frog, Rana limnocharis (Boie, 1834). These three species are common around Nanchong City, in southwestern China, where they live in the same habitat before hibernation. The main objective of this study was to analyze the diets and patterns of coexistence relative to the microhabitat of each species. In the Asiatic toad, based on index of relative importance, the diet was dominated by adult Coleoptera, Isopoda, and Hymenoptera (29.53%, 22.07%, and 15.20%, respectively), while the Guenther's frog and Ricefield frog ingested predominantly Orthoptera (67.44% and 40.94%, respectively). The standardized feeding niche breadth of the Asiatic toad (0.277) was wider than that of the Guentheri frog (0.177) and Ricefield frog (0.269). The overlap in the trophic niche (prey proportion) between the toad and two species of frog was low (toad vs. Guentheri frog, C H = 0.526; toad vs. Ricefield frog, C H = 0.521), while this was high for the two species of frogs (C H = 0.942). The three species also differed in microhabitat use. Asiatic toads showed strong preference for small roads close to shrubs or pre-harvest corn, while Guenther's frogs preferred bare surfaces on habitat edges, and Ricefield frogs showed a preference for bare surfaces as feeding sites in the middle of habitat. The difference in diet observed during three species seems to be explained by the difference in microhabitat use and body size of three species.

Resource partitioning in two carcinophagous confamiliars: distribution and feeding habits of psychrolutid fish on the southern Patagonian shelf

Psychrolutes marmoratus and Cottunculus granulosus, two psychrolutids, inhabit the shelf and continental slope of the southern South America between 45 and 1,250 m. Over this range, the P. marmoratus is found in depths of less than 400 m, whilst C. granulosus inhabits waters of >200 m. There is a trend of increasing total length with increasing water depth for P. marmoratus and the converse for C. granulosus. The total lengths of the species are different in the depth zone that they overlap in (200–400 m), and we hypothesise that this may reduce interspecific competition. Both are specialised carcinophagous feeding on crabs, large isopods and sea spiders, but they also prey upon polychaets and gastropods. There was no difference in the feeding spectra of similar-sized fish sampled at the same depth, indicating a similar foraging strategy. In contrast to this, the feeding spectra are quite different between the species over different depths as well as at different adult sizes. The feeding niche breadth in these species is similar to other slope dwelling fish in the area.

Influence of flood pulses on diet composition and trophic relationships among piscivorous fish in the upper Paraná River floodplain

The aim of this article is to evaluate whether alterations in flood pulses differentially affect diet composition, feeding niche breadth, and diet overlap of piscivorous fish. Species examined were Acestrorhynchus lacustris, Hoplias aff malabaricus, Plagioscion squamosissimus, Rhaphiodon vulpinus, and Salminus brasiliensis. These species were collected with gillnets (different mesh sizes) in the upper Parana River floodplain, during four distinct flood events (four periods; A = 1992/1993; B = 2000; C = 2001; and D = 2002). The volumetric method was chosen to express diet results. Feeding niche breadth was calculated using Levins measure, and diet overlap was evaluated by the Pianka’s Index. Flooding was more intense and lasted longer in the first period (1992/1993—A). Diet composition of the studied species was broad (47 total items consumed). For period A, Prochilodus lineatus was the main item taken by four out of five species. In the other periods, there were relevant alterations in diet, since P. lineatus was not recorded in any stomach of the five species; rather, it was replaced by the shrimp, Macrobrachium amazonicum. Diet overlap was low in all periods. The greatest overlap was obtained in period C for P. squamosissimus and R. vulpinus, due to high consumption of shrimps. There were no significant differences in niche breadth among species. However, the species presented distinct variation patterns in niche breadth. For example, H. aff. malabaricus showed a tendency toward increasing niche over the period, but the other species presented larger niches only during period A. Therefore, it can be concluded that the intensity and duration of the flood pulse influences: (i) the diet composition of piscivores; (ii) the breadth of their niches; and (iii) feeding overlap among species.

Food niche overlap among neotropical frugivorous bats in Costa Rica

Food habits of 15 species of frugivorous bats were studied at La Selva Biological Station, Costa Rica. Eight hundred and fifty-four (854) fecal samples and 169 samples from fruit parts and seeds discarded by bats beneath feeding roosts were analyzed. During eight months of study, 47 fruit species consumed by bats were identified. Five plant genera (Cecropia, Ficus, Piper Solanum, and Vismia) constituted 85% of all plants found in fecal samples. Feeding niche breadth differed significantly among the six most common species of frugivorous bats (Artibeus jamaicensis, Carollia sowelli, C. castanea, C. perspicillata, Dermanura sp., and Glossophaga commissarisi). All species, except for Dermanura sp., showed a diet dominated by one or two plant species. This suggests a pattern of resource partitioning at a generic level, in which Carollia consumed mainly Piper, Artibeus consumed Ficus and Cecropia, and Glossophaga consumed Vismia. Cluster analysis revealed higher values of food niche overlap in congeneric species than among species of different genera. Results show that if food is a limiting factor, mechanisms other than trophic selection must reduce interspecific interference or competition for food in this frugivorous bat guild.

Feeding habits and microhabitat utilization by two syntopic Brazilian Amazonian frogs (Hyla minuta and Pseudopaludicula sp. (gr. falcipes)

We studied the feeding habits and microhabitat use of the Amazonian frogs Hyla minuta and Pseudopaludicula sp. at Serra Norte, Carajás, Brazil. Although living syntopically, the two species differed markedly in both prey types and sizes. Standardized feeding niche breadth of H. minuta (Bst = 0.572) was larger than that of Pseudopaludicula sp. (Bst = 0.149) and their feeding niche overlap was considerably low (10.5%). The two frog species also differed in microhabitat use. When active, Pseudopaludicula sp. were found partially submerged at the lake border whereas H. minuta were found predominantly on Nymphaea sp. leaves. Although we have not evaluated taxonomic effects on diet composition, differences in diet may be partially explained by differences in microhabitat use and frogs' size.

Decrease in feeding niche breadth of Melasoma lapponica (Coleoptera: Chrysomelidae) with increase in pollution.

We studied host-plant preference and performance of the leaf beetle, Melasoma lapponica, around Severonikel smelter situated in Monchegorsk, Russia. The breadth of feeding niche (Smith's measure) based on both field counts and preference tests decreased with an increase of ambient SO2 concentration, but showed no relationship with either metal pollutants or beetle population densities. In heavily polluted plots (mean annual SO2 concentrations 400-1000 μg/m3) the beetles concentrated on Salix borealis, Whereas in moderately and slightly polluted plots they used other willow species as well. No difference in survival was revealed between M. lapponica fed with leaves of S. borealis from heavily and sloghtly polluted plots. However, performance of larvae fed with Salix caprea and S. Phylicifolia was significantly lower when leaves were collected from heavily polluted plots. In these plots beetles clearly preferred S. borealis, the only species assuring high survival of M. lapponica under strong pollution impact. Decrease in preference of two less favourable hosts, S. caprea and S. phylicifolia, with increase in pollution can therefore be considered as an adaptive response of M. lapponica to pollution-induced changes in host-plant quality.

Wild reindeer foraging‐niche organization

Part 1:Diet selection was studied on free‐ranging reindeer fitted with an esophageal fistula (EF) and by analysis of rumen samples from reindeer shot in the field. Plant density was assessed from quadrats on field plots. Three measures of palatability were used, the nitrogen, fiber, and total non structural carbohydrate (TNC) contents of samples from clipped vegetation. As lichen density decreased the EK reindeer included progressively more vascular litter and pieces of winter dormant species in their diet. Diets with highest TNC and N/F and the lowest fiber, providing the most readily digestible diets, were selected. The combined density‐quality criterion gave the best prediction of their diets. In summer, forbs, and to some extent grasses and dwarf shrubs, were selected. Plants of highest density and in an early growth phase gave the best prediction of summer diets.In winter the variety of vascular plants utilized increased with increasing herd size and decreasing density of lichens in the vegetation. The width of diets was a function of diversity of available plants. It is suggested that dietary selection by reindeer has been a three stage process: evolution of a gastro‐intestinal system capable of digesting lichens containing secondary compounds, behavioural tracking of the plant production pulse, and diet width scaling according to density‐quality of all potential foods.Part 2:Wild reindeer closely followed the wave of vascular plant production in spring and summer with a significant correlation being found between the daily foraging time per habitat type and the highest concentration of green phytomass. Snow‐bed meadows were the most consistently selected vegetation type by the four herds studied, viz. Hardangervidda, Snøhetta, Prudhoe Bay, and Svalbard, during the summer. Habitat niche‐breadths were narrow during the winter, largely due to the limitation of access to the food supply by the snow‐cover, broadened as the landscape became clear of snow, narrowed again with the initiation of plant growth and broadened once more as the wave of plant production reached all habitat types.At high levels of food resources the alpine herd (Hardangervidda) narrowed the feeding niche breadth (or adopted a selective feeding strategy) as the habitat niche breadth increased. The high arctic herd (Svalbard) living in the least productive environment, at the same time of year adopted a generalist feeding strategy as their habitat niche breadth expanded.Part 3:In this part the temporal organization of a low‐alpine herd of reindeer (Hardangervidda) is described, and subsequently compared with those of two arctic herds. Their foraging efficiencies under different degrees of food availability were analysed, in order to test the hypothesis that food intake changes in response to the prevailing state of the food resources.The number of daily feeding bouts increased from 2 to 6 as the diet changed from the winter to the summer pasturage. Strong winds in winter and insect harassment in summer severely depressed the daily time spent foraging. When these environmental factors were accounted for no significant inter‐seasonal differences in daily foraging time of the low alpine herd were found; on average 50% of each day was spent grazing, of which 78% of the time was spent on actual ingestion (feeding rate). The feeding rate within the active periods varied with the snow‐depth, due to the need to dig a food crater in the snow and due to the particular selective feeding strategy adopted. The data from the present and from other studies suggest that the foraging efficiency of wild reindeer, expressed as their daily food intake follows a Holling type II functional response as food availability changes.Part 4:Sheep is the only sympatric ruminant which grazes with the reindeer on alpine pastures in Norway. The inter‐specific niche relationships ot the wild reindeer and the domestic sheep in summer were studied on part of the western Hardangervidda. to test the hypothesis of inter‐specific competition. Three niche dimensions were meas‐ured, diel, habitat utilization, and spatial distribution. The estimates of the degree of overlap obtained suggest that this is relatively high for diet and habitat utilization but low for spatial distribution, which leads to a low degree of foraging interference. Since the intensity of both interspeeific and intra‐specific competition depends on the ratio of the herbivore densities to the food resource density, the degree ol overlap in utilization by the two species tell us nothing about the degree of competition. Present numbers of both species on Hardangervidda have a beneficial influence on the vegetation, by opening‐up the shrub‐layer canopy and thus facilitating the main‐tenance of grasses and forbs in the field layer, which has a higher carrying capacity for ruminants. The balance between the beneficial effects and inter‐generic competition (if any) deriving from the present‐day stocking rales is so tar unknown. Only long‐term monitoring of the performance of both populations will shed light on this competitive aspect.