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Freshwater bivalves are key faunal elements of aquatic ecosystems. Native species declines are paralleled by increasing distribution and abundances of non-native species. Appropriate management of both groups depends on knowledge of their interactions, which remains limited. Herein, we systematically review the current knowledge status of native and non-native bivalves in Europe, analyzing their functional interactions as well as niche and distribution overlaps between species. We also review existing management tools for non-native species in light of their applicability and sustainability. Strong and multiple interactions as well as niche overlaps between native and non-native bivalves already exist in Central Europe, especially with regard to Dreissena spp., Corbicula spp., and Sinanodonta woodiana . Direct competition is low with native species that have a high degree of specialization such as Margaritifera margaritifera , whereas the greatest niche overlap and competition occurs in generalist species such as Anadonta anatina , Unio pictorum , and S. woodiana . Early detection and preventive measures against undesired species are most successful in limiting their spread. Most methods for managing non-native species are unspecific and thus also include undesired side effects on endangered native species. The conservation and restoration of functionally intact bivalve habitats are the most sustainable and most resilient ways of management.

Classic and contemporary trophic ecology-based studies have shown that most non-native freshwater fish species (NNS) that integrate into novel environments have the potential to influence the recipient ecosystems’ structure and function. However, the interspecific trophic interactions amongst co-occurring NNS within invaded systems remain poorly studied. Here, we used carbon ( δ 13 C) and nitrogen ( δ 15 N) stable isotope analyses to examine general fish trophic diversity patterns (native and non-native fishes) and to explore trophic niche patterns amongst co-occurring NNS within a flow-modified river system, the Great Fish River (South Africa). The system was characterised by isotopic variation, which revealed spatial differences in trophic complexity from uninvaded headwater tributaries to invaded mainstem and downstream sections. Two of the invaded sections, the upper mainstem of the Great Fish River (UGFR) and the Koonap River, had low isotopic overlaps between NNS and the native fish assemblages. Furthermore, co-occurring NNS in these two invaded sections had variable isotopic niche sizes and low interspecific isotopic niche overlaps, suggesting the potential for trophic differentiation. By comparison, there was evidence of high resource use patterns among NNS within the lower mainstem section of the Great Fish River (LGFR), which likely reflected trophic plasticity. Overall, results of this study provided evidence of both trophic niche differentiation (UGFR and Koonap River) and niche overlap (LGFR) as probable mechanisms of co-occurrences of the non-native fishes within different invaded sections of the Great Fish River system, and underscores the difficulties associated with predicting their trophic impacts.

Some parasitic plants are major pests in agriculture, but how this might be affected by climate change remains largely unknown. In this study, we assessed this question for five generalist holoparasitic Cuscuta species (smoothseed alfalfa dodder [Cuscuta approximata Bab.], alfalfa dodder [Cuscuta europaea L.], soybean dodder [Cuscuta chinensis C. Wright], Peruvian dodder [Cuscuta australis R. Br.], and Japanese dodder [Cuscuta japonica Choisy]) and two of their main Leguminosae host crop species (soybean [Glycine max (L.) Merr.] and alfalfa [Medicago sativa L.]. For each of the five Cuscuta species and the two crop species, we ran MaxEnt models, using climatic and soil variables to predict their potential current distributions and potential future distributions for 2070. We ran species distribution models for all seven species for multiple climate change scenarios, and tested for changes in the overlap of suitable ranges of each crop with the five parasites. We found that annual mean temperature and isothermality are the main bioclimatic factors determining the suitable habitats of the Cuscuta species and their hosts. For both host species, the marginally to optimally suitable area will increase by 2070 for all four representative concentration pathway scenarios. For most of the Cuscuta species, the marginally to optimally suitable area will also increase. While the suitable areas for both the hosts and the parasites will increase overall, Schoener’s D, indicating the relative overlap in suitable area, will change only marginally. However, the absolute area of potential niche overlap may increase up to 6-fold by 2070. Overall, our results indicate that larger parts of the globe will become suitable for both host species, but that they could also suffer from Cuscuta parasitism in larger parts of their suitable ranges.

The fall webworm moth, Hyphantria cunea, is a highly invasive defoliator that threatens forest ecosystems in China. The parasitoid wasp Chouioia cunea has been mass‐reared and widely released for biological control of H. cunea. Climate change can alter climatic suitability and potentially reshape the spatial matching between hosts and natural enemies, thereby affecting biological control outcomes. Here, we used an ensemble species distribution modeling (SDM) framework to project current (WorldClim 1971–2000) and future (2030s and 2050s) suitable habitats for H. cunea and C. cunea in China under three Shared Socioeconomic Pathways (SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5). We quantified changes in suitable area and host‐parasitoid overlap and estimated climatic niche overlap using Schoener's D. Both species were projected to maintain broadly similar suitability patterns with a general northward shift and an increase in total suitable area under several scenarios, leading to extensive overlaps in eastern and central China. Schoener's D (0.738) indicated substantial climatic niche overlap between the two species. Among the retained predictors, the minimum temperature of the coldest month (bio6) and the Human Influence Index were most important for C. cunea. Under SSP5‐8.5, overlapping suitable areas were projected to increase to approximately 1.15 million km2 by the 2050s. These results provided a spatial basis for anticipating where biocontrol releases may be most effective and where potential host‐parasitoid mismatches could require strengthened monitoring under climate change. *Hyphantria cunea* is a highly invasive forest pest in China, and its parasitoid *Chouioia cunea* is widely used for biological control, though climate change may alter their spatial matching. Using ensemble species distribution models under multiple SSP scenarios, we found that suitable habitats for both species are projected to expand, with substantial niche overlap (Schoener's D = 0.738), particularly in eastern and central China. These results provide a basis for optimizing climate‐adaptive release strategies of *C. cunea* in future pest management programs.

This study combines niche overlap analysis with species distribution modeling (SDM) to examine the niche dynamics of Atlantoxerus getulus, a ground squirrel native to Morocco and Algeria that has been introduced to the Canary Islands. We compiled 1272 records of A. getulus in its native and exotic ranges and five bioclimatic variables for present and future climate conditions for the years 2050 and 2070. We assessed the ecological niche of the species using exploratory and ordination analyses, followed by the prediction of its distribution using the SpatialMaxent model. Our results showed that the niches of A. getulus exhibited equivalence (p > 0.05) and significant similarity (p < 0.05) between the native and exotic ranges. No observed niche expansion in the exotic area is shown to be associated with complete niche stability. However, 90% of the niche in the Canary Islands remains unfilled, suggesting potential for further invasion. Our results highlighted habitat contractions ranging from 41% (SSP245-2050) to 60% (SSP585-2070), associated with a shift in the centroid of suitable habitat towards the Atlantic coast. These contractions are particularly severe in Algeria, where suitable habitats could disappear by 2050, contrasting with stable habitats maintained in the Canary Islands under all scenarios. Urgent habitat restoration in Algeria is crucial, including efforts to combat poaching. In Morocco, targeted in situ conservation is recommended, while in the Canary Islands, the focus should be on invasive species management and public awareness campaigns to prevent further spread.

Aim Populations of large ungulates are dwindling worldwide. This is especially so for wild sheep, which compete with livestock for forage, are disturbed by shepherds and their dogs, and are exposed to disease transmissions from livestock. Our aim was to assess spatial patterns in realized niche overlap between wild and domestic sheep to better understand where potential competition might arise, and thus to identify priority areas for wild sheep recovery. Location Southern Caucasus (220,000 km2). Methods We studied Gmelin's mouflon (Ovis orientalis gmelinii), an ancestor of domestic sheep, to investigate seasonal habitat use and niche overlap with domestic sheep. To map habitat, we analysed mouflon occurrences collected during 2006–2016, and domestic sheep occurrences from shepherd camp locations digitized on high‐resolution satellite imagery. We mapped areas of potential competition between mouflon and domestic sheep and assessed potential habitat displacement. Results Mouflon and domestic sheep niches overlapped substantially (overlap index I = 0.89, where 1 means perfect overlap) but were not identical. Mouflon habitat was less widespread than domestic sheep habitat (14,000 vs. 40,270 km2) and tended to be located in more rugged areas with less vegetation cover. We identified 51 priority patches as reintroduction candidates if grazing pressure and poaching were reduced. Main conclusions Our results suggest that competition with domestic sheep might have pushed mouflon into marginal habitat. Thus, conservation efforts focusing on current mouflon habitat might miss suitable reintroduction sites. We demonstrate that a combined habitat model for wild and domestic sheep can identify general sheep habitat, which might be more useful for conservation planning than understanding current mouflon habitat selection. Our results highlight that considering competition with livestock is important for large ungulate conservation, both in terms of reactive (e.g., lessening livestock pressure in prime habitat) and proactive strategies (e.g., reintroduction in areas with low contemporary overlap).

Aim The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of gentoo penguins (Pygoscelis papua) distributed across Antarctica and sub-Antarctic Islands are subject to spatially explicit ecological conditions that have limited gene flow, facilitating genetic differentiation, and thereby speciation processes. Location Antarctica and sub-Antarctic area. Methods We identify divergent lineages for gentoo penguins using ddRAD-seq and mtDNA, and generated species distribution models (SDMs) based on terrestrial and marine parameters. Results Analyses of our genomic data supports the existence of four major lineages of gentoo penguin: (i) spanning the sub-Antarctic archipelagos north of the Antarctic Polar Front (APF); (ii) Kerguelen Island; (iii) South America; and (iv) across maritime Antarctic and the Scotia Arc archipelagos. The APF, a major current system around Antarctica, acts as the most important barrier separating regional sister lineages. Our ecological analyses spanning both the terrestrial (breeding sites) and marine (feeding sites) realms recover limited niche overlap among the major lineages of gentoo penguin. We observe this pattern to correspond more closely with regional differentiation of marine conditions than to terrestrial macroenvironmental features. Main conclusions Recognition of regional genetic lineages as discrete evolutionary entities that occupy distinct ecological niches and also differ morphologically should be considered a priority for conservation. Gentoo penguins provide a good example of how conservation policy can be directly impacted by new insights obtained through the integration of larger genomic datasets with novel approaches to ecological modelling. This is particularly pertinent to polar environments that are among the most rapidly changing environments on earth.

Zebra mussels (Dreissena polymorpha) filter feed phytoplankton and reduce available pelagic energy, potentially driving fish to use littoral energy sources in lakes. However, changes in food webs and energy flow in complex fish communities after zebra mussel establishment are poorly known. We assessed impacts of zebra mussels on fish littoral carbon use, trophic position, isotopic niche size, and isotopic niche overlap among individual fish species using δ13C and δ15N data collected before (2014) and after (2019) zebra mussel establishment in Lake Ida, MN. Isotope data were collected from 11 fish species, and from zooplankton and littoral invertebrates to estimate baseline isotope values. Mixing models were used to convert fish δ13C and δ15N into estimates of littoral carbon and trophic position, respectively. We tested whether trophic position, littoral carbon use, isotopic niche size, and isotopic niche overlap changed from 2014 to 2019 for each fish species. We found few effects on fish trophic position, but 10 out of 11 fish species increased littoral carbon use after zebra mussel establishment, with mean littoral carbon increasing from 43% before to 67% after establishment. Average isotopic niche size of individual species increased significantly (2.1-fold) post zebra mussels, and pairwise-niche overlap between species increased significantly (1.2-fold). These results indicate zebra mussels increase littoral energy dependence in the fish community, resulting in larger individual isotopic niches and increased isotopic niche overlap. These effects may increase interspecific competition among fish species and could ultimately result in reduced abundance of species less able to utilize littoral energy sources.

The community structure and ecological niche of benthic macroinvertebrates in the upper Yarlung Zangbo River were analyzed in April and September 2023. The benthic macroinvertebrate community largely comprises aquatic insects, with Diptera accounting for approximately half. Commonly observed were Chironomus anthracinus, Tadamus sp.1, Piscicola geometra, species of the family Corixidae spp. and the genera Monodiamesa sp., Apatania sp., and Valvata sp. in April, and Orthocladius sp.1, Gammarus sp., Isoperla sp., Nais sp., Baetis sp., Monodiamesa sp., Tanytarsus sp., Ilisia sp., Nebrioporus sp. and species of the family Corixidae spp. in September. The α-diversity analysis showed significant seasonal differences (p < 0.05) in Shannon–Wiener diversity variable and Margalef richness variable. The Pielou evenness variable did not show seasonal effects (p > 0.05). The β-diversity April/September differences can be attributed to species turnover rather than to nestedness, indicating that benthic macroinvertebrate diversity protection strategies are critical to all areas of the river. In April, Chironomus anthracinus exhibited the broadest ecological niche, and, in September, the widest niche was observed in Gammarus sp. The largest observed ecological niche overlap values were between Chironomus anthracinus and Valvata sp. in April and Gammarus sp. and Ilisia sp. in September, indicating interspecific competition. The study clarifies the diversity status of benthic macroinvertebrates in the upper Yarlung Zangbo River and provides data for related research to facilitate formulation of biodiversity conservation policies.

Diversification is frequently associated with change—anything from colonizing a new area to evolving a new trait. Once a lineage changes, the organisms may be able to exploit previously unavailable ecological opportunities and release pressures from predators, parasites, and competitors, which may increase the speciation rate. Modern teiid lizards originated in South America but managed to colonize and diversify in North America. We assessed whether geographic distribution, body size, and body temperatures are associated with teiid diversification using GeoHiSSE and inverse equal‐splits statistics with simulation tests. We also estimated speciation rates with MiSSE to account for the effect of unmeasured variables. Moreover, we assessed the ecological niche overlap between North American (including Caribbean) teiids and their sister clade in South America. Our results indicate that only distribution range affected diversification, but we discuss that the available data might not have been enough to assess the effect of body temperatures. We also show that North American teiids have a broader ecological niche encompassing almost all environmental conditions used by their sister clade in South America but expanding mainly toward arid areas. Our results suggest that this expansion significantly impacted teiid diversification due to the seizing of ecological opportunities or ecological release, but we do not discard possible effects of phenotypic evolution. Teiids increased their diversification rates upon colonization of North America, which was associated with an ecological niche expansion toward drier areas. This increment in diversification was not shown to be associated with phenotypic traits, which suggests it was due to ecological opportunity and/or ecological release.