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1. Convergent niche shifts of endangered parrots (genus Amazona ) during successful establishment in urban southern California

   https://doi.org/10.1111/ddi.13817  

   Ramirez, Brenda R. ; Freeland, Rowdy J. ; Muhlheim, Allison ; Zellmer, Amanda J. ; DeRaad, Devon A. ; Kirsch, Eliza J. ; Mutchler, Marquette J. ; Secor, Maeve B. ; Reckling, Kelsey R. ; Schedl, Margaret E. ; et al ( February 2024 , Diversity and Distributions)

   Introduced species offer insight on whether and how organisms can shift their ecological niches during translocation. The genusAmazonaoffers a clear test case, where sister species Red‐crowned (A. viridigenalis) and Lilac‐crowned Parrots (A. finschi) have established breeding populations in southern California following introduction via the pet trade from Mexico where they do not coexist. After establishment in the 1980s, introduced population sizes have increased, with mixed species flocks found throughout urban Los Angeles. Here, we investigate the differences between the environmental conditions of the native and introduced ranges of these now co‐occurring species.

   Southern California and Mexico.

   Using environmental data on climate and habitat from their native and introduced ranges, we tested whether Red‐crowned and Lilac‐crowned Parrots have divergent realized niches between their native ranges, and whether each species has significantly shifted its realized niche to inhabit urban southern California. We also analysed data from Texas and Florida introductions of Red‐crowned Parrots for comparative analysis.

   There are significant differences in the native‐range niches of both parrot species, but a convergence into a novel, shared environmental niche into urban southern California, characterized by colder temperatures, less tree cover and lower rainfall. Texas and Florida Red‐crowned Parrots also show evidence for niche shifts with varying levels of niche conservatism through the establishment of somewhat different realized niches.

   Despite significant niche shifts, introduced parrots are thriving, suggesting a broad fundamental niche and an ability to exploit urban resources. Unique niche shifts in different U.S. introductions indicate thatAmazonaparrots can adapt to diverse environmental conditions, with cities offering a resource niche and the timing of introduction playing a crucial role. Cities can potentially serve as refugia for threatened parrot species, but the risk of hybridization between species emphasizes the need for ongoing monitoring and genetic investigations.

    

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2. Climatic niche comparisons of eastern North American and eastern Asian disjunct plant genera

   https://doi.org/10.1111/geb.13504  

   Melton, Anthony E. ; Clinton, Matthew H. ; Wasoff, Donald N. ; Lu, Limin ; Hu, Haihua ; Chen, Zhiduan ; Ma, Keping ; Soltis, Douglas E. ; Soltis, Pamela S. ( April 2022 , Global Ecology and Biogeography)

   While the floras of eastern Asia (EA) and eastern North America (ENA) share numerous genera, they have drastically different species richness. Despite an overall similarity in the quality of their temperate climates, the climate of EA is more spatially heterogeneous than that of ENA. Spatial environmental heterogeneity has been found to play a key role in influencing species richness in some regions. Here, we tested the following hypotheses: (a) EA species will occupy larger climatic niches than their ENA congeners, (b) congeners of EA‐ENA disjunct genera will occupy statistically equivalent climatic niches, and (c) congeners of EA‐ENA disjunct genera will occupy more similar climatic niches than expected by their respective physiographic context.

   North America and Asia.

   Present.

   Seed plants.

   Predictions generated by ecological niche models (ENMs) were compared for 88 species across 31 EA‐ENA disjunct genera. ENM predictions were assessed for geographic and ecological breadth. Tests for niche equivalency and similarity were performed for congeneric species pairs to determine if species of disjunct genera have experienced niche conservatism or divergence.

   EA species tend to occupy greater amounts of climatic niche space than their close relatives in ENA. Over two‐thirds of the conducted niche comparisons show that EA‐ENA congeners either occupy equivalent climatic niche space within these broader climatic regimes or occupy non‐equivalent niches that are as similar as expected given their physiographic contexts.

   EA species tend to occupy larger climatic niches, and congeners of EA‐ENA disjunct genera tend to occupy equivalent/similar niche space within their respective distributions, with differences in occupied niches possibly due to their respective physiographic contexts, highlighting how niche‐neutral processes and niche conservatism may affect the distributions of disjunct species.

    

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3. Niche modelling predicts that soil fungi occupy a precarious climate in boreal forests

   https://doi.org/10.1111/geb.13684  

   Qin, Clara ; Pellitier, Peter T. ; Van Nuland, Michael E. ; Peay, Kabir G. ; Zhu, Kai ( April 2023 , Global Ecology and Biogeography)

   Efforts to predict the responses of soil fungal communities to climate change are hindered by limited information on how fungal niches are distributed across environmental hyperspace. We predict the climate sensitivity of North American soil fungal assemblage composition by modelling the ecological niches of several thousand fungal species.

   One hundred and thirteen sites in the United States and Canada spanning all biomes except tropical rain forest.

   Fungi.

   2011–2018.

   We combine internal transcribed spacer (ITS) sequences from two continental‐scale sampling networks in North America and cluster them into operational taxonomic units (OTUs) at 97% similarity. Using climate and soil data, we fit ecological niche models (ENMs) based on logistic ridge regression for all OTUs present in at least 10 sites (n = 8597). To describe the compositional turnover of soil fungal assemblages over climatic gradients, we introduce a novel niche‐based metric of climate sensitivity, the Sørensen climate sensitivity index. Finally, we map climate sensitivity across North America.

   ENMs have a mean out‐of‐sample predictive accuracy of 73.8%, with temperature variables being strong predictors of fungal distributions. Soil fungal climate niches clump together across environmental space, which suggests common physiological limits and predicts abrupt changes in composition with respect to changes in climate. Soil fungi in North American climates are more likely to be limited by cold and dry conditions than by warm and wet conditions, and ectomycorrhizal fungi generally tolerate colder temperatures than saprotrophic fungi. Sørensen climate sensitivity exhibits a multimodal distribution across environmental space, with a peak in climates corresponding to boreal forests.

   The boreal forest occupies an especially precarious region of environmental space for the composition of soil fungal assemblages in North America, as even small degrees of warming could trigger large compositional changes characterized mainly by an influx of warm‐adapted species.

    

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4. Evolution of compound eye morphology underlies differences in vision between closely related Drosophila species

   https://doi.org/10.1186/s12915-024-01864-7  

   Buffry, Alexandra D. ; Currea, John P. ; Franke-Gerth, Franziska A. ; Palavalli-Nettimi, Ravindra ; Bodey, Andrew J. ; Rau, Christoph ; Samadi, Nazanin ; Gstöhl, Stefan J. ; Schlepütz, Christian M. ; McGregor, Alistair P. ; et al ( March 2024 , BMC Biology)

   Insects have evolved complex visual systems and display an astonishing range of adaptations for diverse ecological niches. Species ofDrosophila melanogastersubgroup exhibit extensive intra- and interspecific differences in compound eye size. These differences provide an excellent opportunity to better understand variation in insect eye structure and the impact on vision. Here we further explored the difference in eye size betweenD. mauritianaand its sibling speciesD. simulans.

   We confirmed thatD. mauritianahave rapidly evolved larger eyes as a result of more and wider ommatidia thanD. simulanssince they recently diverged approximately 240,000 years ago. The functional impact of eye size, and specifically ommatidia size, is often only estimated based on the rigid surface morphology of the compound eye. Therefore, we used 3D synchrotron radiation tomography to measure optical parameters in 3D, predict optical capacity, and compare the modelled vision to in vivo optomotor responses. Our optical models predicted higher contrast sensitivity forD. mauritiana, which we verified by presenting sinusoidal gratings to tethered flies in a flight arena. Similarly, we confirmed the higher spatial acuity predicted forDrosophila simulanswith smaller ommatidia and found evidence for higher temporal resolution.

   Our study demonstrates that even subtle differences in ommatidia size between closely relatedDrosophilaspecies can impact the vision of these insects. Therefore, further comparative studies of intra- and interspecific variation in eye morphology and the consequences for vision among otherDrosophilaspecies, other dipterans and other insects are needed to better understand compound eye structure–function and how the diversification of eye size, shape, and function has helped insects to adapt to the vast range of ecological niches.

    

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5. Fine‐scale environmental heterogeneity and spatial niche partitioning among spring‐flowering forest herbs

   https://doi.org/10.1002/ajb2.1593  

   Beck, Jared J. ; Givnish, Thomas J. ( January 2021 , American Journal of Botany)

   Environmental heterogeneity influences plant distributions and diversity at several spatial scales. In temperate forests, fine‐scale environmental variation may promote local coexistence among herbaceous species by allowing plants to spatially partition microsites within forest stands. Here we argue that shallow soils, low soil water‐holding capacity and fertility, and reduced light near tree boles should favor short, shallow‐rooted, evergreen species likeAnemone acutilobawith low moisture, nutrient, and light requirements. Farther from trees, richer, deeper soils should favor taller, deeper‐rooted herbs with greater moisture and nutrient demands, such asSanguinaria canadensisandTrillium flexipes.

   We tested these hypotheses by mapping the fine‐scale distributions ofAnemone,Sanguinaria, andTrilliumindividuals within a 50 × 50 m plot, comparing local species’ distributions with respect to soil depth and proximity to neighboring trees, and characterizing intraspecific and interspecific spatial associations.

   Local plant distributions were consistent with our predictions based on leaf height, physiology, and phenology.Anemonewas found in microsites on shallower soils and closer to trees than eitherSanguinariaorTrillium. In all three species, individual plants were spatially aggregated within 2 m, but spatially segregated from individuals of the other species beyond 2 m.

   Differential plant responses to fine‐scale environmental heterogeneity and observed spatial associations suggest that local species‐environment associations could facilitate coexistence. These findings illustrate how fine‐scale environmental heterogeneity coupled with phenological and physiological differences likely contribute to spatial niche partitioning among spring‐flowering forest herbs and maintain high local plant diversity within temperate forests.

    

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