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1. E nvironmental niche adaptation revealed through fine scale phenological niche modelling

   https://doi.org/10.1111/jbi.13663  

   Van_Dam, Matthew_H ; Rominger, Andrew_J ; Brewer, Michael_S ( July 2019 , Journal of Biogeography)

   Phenology, the temporal response of a population to its climate, is a crucial behavioural trait shared across life on earth. How species adapt their phenologies to climate change is poorly understood but critical in understanding how species will respond to future change. We use a group of flies (Rhaphiomidas) endemic to the North American deserts to understand how species adapt to changing climatic conditions. Here, we explore a novel approach for taxa with constrained phenologies aimed to accurately model their environmental niche and relate this to phenological and morphological adaptations in a phylogenetic context.

   Insecta, Diptera, Mydidae,Rhaphiomidas.

   North America, Mojave, Sonoran and Chihuahuan Deserts.

   We gathered geographical and phenological occurrence data for the entire genusRhaphiomidas, and, estimated a time calibrated phylogeny. We compared Daymet derived temperature values for a species adult occurrence period (phenology) with those derived from WorldClim data that is partitioned by month or quarter to examine what effect using more precise data has on capturing a species’ environmental niche. We then examined to what extent phylogenetic signal in phenological traits, climate tolerance and morphology can inform us about how species adapt to different environmental regimes.

   We found that the Bioclim temperature data, which are averages across monthly intervals, poorly represent the climate windows to which adult flies are actually adapted. Using temporally relevant climate data, we show that many species use a combination of morphological and phenological changes to adapt to different climate regimes. There are also instances where species changed only phenology to track a climate type or only morphology to adapt to different environments.

   Without using a fine‐scale phenological data approach, identifying environmental adaptations could be misleading because the data do not represent the conditions the animals are actually experiencing. We find that fine‐scale phenological niche models are needed when assessing taxa that have a discrete phenological window that is key to their survival, accurately linking environment to morphology and phenology. Using this approach, we show thatRhaphiomidasuse a combination of niche tracking and adaptation to persist in new niches. Modelling the effect of phenology on such species’ niches will be critical for better predictions of how these species might respond to future climate change.

    

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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. Untangling the importance of niche breadth and niche position as drivers of tree species abundance and occupancy across biogeographic regions

   https://doi.org/10.1111/geb.13139  

   Vela Díaz, Dilys M. ; Blundo, Cecilia ; Cayola, Leslie ; Fuentes, Alfredo F. ; Malizia, Lucio R. ; Myers, Jonathan A. ; Pither, ed., Jason ( June 2020 , Global Ecology and Biogeography)

   Ecological niches shape species commonness and rarity, yet, the relative importance of different niche mechanisms within and across ecosystems remains unresolved. We tested the influence of niche breadth (range of environmental conditions where species occur) and niche position (marginality of a species’ environmental distribution relative to the mean environmental conditions of a region) on tree‐species abundance and occupancy across three biogeographic regions.

   Argentinian Andes; Bolivian Amazon; Missouri Ozarks.

   2002–2010.

   Trees.

   We calculated abiotic‐niche breadths and abiotic‐niche positions using 16 climate, soil and topographic variables. For each region, we used model selection to test the relative influence of niche breadth and niche position on local abundance and occupancy in regional‐scale networks of 0.1‐ha forest plots. To account for species–environment associations caused by other mechanisms (e.g., dispersal), we used null models that randomized associations between species occurrences and environmental variables.

   We found strong support for the niche‐position hypothesis. In all regions, species with higher local abundance and occupancy occurred in non‐marginal environments. Observed relationships between occupancy and niche position also differed from random species–environment associations in all regions. Surprisingly, we found little support for the niche‐breadth hypothesis. Observed relationships between both local abundance and niche breadth, and occupancy and niche breadth, did not differ from random species–environment associations.

   Niche position was more important than niche breadth in shaping species commonness and rarity across temperate, sub‐tropical and tropical forests. In all forests, tree species with widespread geographic distributions were associated with environmental conditions commonly found throughout the region, suggesting that niche position has similar effects on species occupancy across contrasting biogeographic regions. Our findings imply that conservation efforts aimed at protecting populations of common and rare tree species should prioritize conservation of both common and rare habitats.

    

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4. Linking climate niches across seasons to assess population vulnerability in a migratory bird

   https://doi.org/10.1111/gcb.15639  

   Ruegg, Kristen ; Anderson, Eric C. ; Somveille, Marius ; Bay, Rachael A. ; Whitfield, Mary ; Paxton, Eben H. ; Smith, Thomas B. ( May 2021 , Global Change Biology)

   Global loss of biodiversity has placed new urgency on the need to understand factors regulating species response to rapid environmental change. While specialists are often less resilient to rapid environmental change than generalists, species‐level analyses may obscure the extent of specialization when locally adapted populations vary in climate tolerances. Until recently, quantification of the degree of climate specialization in migratory birds below the species level was hindered by a lack of genomic and tracking information, but recent technological advances have helped to overcome these barriers. Here we take a genome‐wide genetic approach to mapping population‐specific migratory routes and quantifying niche breadth within genetically distinct populations of a migratory bird, the willow flycatcher (Empidonax traillii), which exhibits variation in the severity of population declines across its breeding range. While our sample size is restricted to the number of genetically distinct populations within the species, our results support the idea that locally adapted populations of the willow flycatcher with narrow climatic niches across seasons are already federally listed as endangered or in steep decline, while populations with broader climatic niches have remained stable in recent decades. Overall, this work highlights the value of quantifying niche breadth within genetically distinct groups across time and space when attempting to understand the factors that facilitate or constrain the response of locally adapted populations to rapid environmental change.

    

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5. Climatic niche evolution in turtles is characterized by phylogenetic conservatism for both aquatic and terrestrial species

   https://doi.org/10.1111/jeb.13395  

   Rodrigues, João Fabrício M. ; Villalobos, Fabricio ; Iverson, John B. ; Diniz‐Filho, José Alexandre F. ( November 2018 , Journal of Evolutionary Biology)

   Understanding how the climatic niche of species evolved has been a topic of high interest in current theoretical and applied macroecological studies. However, little is known regarding how species traits might influence climatic niche evolution. Here, we evaluated patterns of climatic niche evolution in turtles (tortoises and freshwater turtles) and whether species habitat (terrestrial or aquatic) influences these patterns. We used phylogenetic, climatic and distribution data for 261 species to estimate their climatic niches. Then, we compared whether niche overlap between sister species was higher than between random species pairs and evaluated whether niche optima and rates varied between aquatic and terrestrial species. Sister species had higher values of niche overlap than random species pairs, suggesting phylogenetic climatic niche conservatism in turtles. The climatic niche evolution of the group followed an Ornstein–Uhlenbeck model with different optimum values for aquatic and terrestrial species, but we did not find consistent evidence of differences in their rates of climatic niche evolution. We conclude that phylogenetic climatic niche conservatism occurs among turtle species. Furthermore, terrestrial and aquatic species occupy different climatic niches but these seem to have evolved at similar evolutionary rates, reinforcing the importance of habitat in understanding species climatic niches and their evolution.

    

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