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1. Predicting climate change impacts on critical fisheries species in Fijian marine systems and its implications for protected area spatial planning

   https://doi.org/10.1111/ddi.13709  

   Lawson, Katherine N. ; Lang, Karina M. ; Rabaiotti, Daniella ; Drew, Joshua ( August 2023 , Diversity and Distributions)

   Spatially explicit protections of coastal habitats determined on the current distribution of species and ecosystems risk becoming obsolete in 100 years if the movement of species ranges outpaces management action. Hence, a critical step of conservation is predicting the efficacy of management actions in future. We aimed to determine how foundational, habitat‐building species will respond to climate change in Fiji.

   The Republic of Fiji.

   We develop species distribution models (SDMs) using MaxEnt, General Additive Models and Boosted Regression Trees and publicly available data from the Global Biodiversity Information Facility to predict changes in distribution of suitable habitat for mangrove forests, coral habitat, seagrass meadows and critical fisheries invertebrates under several IPCC climate change scenarios in 2070 or 2100. We then overlay predicted distribution models onto existing Fijian protected area network to assess whether today's conservation measures will afford protection to tomorrow's distributions.

   We found that mangrove suitability is projected to decrease along the Coral Coast and increase northward towards the Yasawa Islands due to precipitation changes. The response of seagrass meadows was predicted to be inconsistent and dependent on the climate scenario. Meanwhile, suitability for coral reefs was not predicted to decline significantly overall. The mangrove crabScylla serrata, an important resource for fisherwomen in Fiji, is projected to increase in habitat suitability while economically important sea cucumber species will have highly variable responses to climate change.

   Species distribution models are a critical tool for conservation managers, as linking spatial distribution data with future climate change scenarios can aid in the creation and resiliency of protected area programmes. New protected area designations should consider the future distribution of species to maximize benefits to those taxa.

    

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2. Historical interactions are predicted to be disrupted under future climate change: The case of lace lichen and valley oak

   https://doi.org/10.1111/jbi.13442  

   Zhao, Jian‐Li ; Werth, Silke ; Ikegami, Makihiko ; Gugger, Paul F. ; Sork, Victoria L. ( November 2018 , Journal of Biogeography)

   The distributions and interactions of co‐occurring species may change if their ranges shift asymmetrically in response to rapid climate change. We aim to test whether two currently interacting taxa, valley oak (Quercus lobata) and lace lichen (Ramalina menziesii), have had a long‐lasting historical association and are likely to continue to associate in the future.

   Central western California, western United States of America

   Using population genetic analyses andMaxEntsoftware for ecological niche modelling, we estimate species’ distributions during the Last Interglacial, the Last Glacial Maximum, present, and future periods. Mantel and vertex (genetic connection) tests were used to examine the spatial congruence among taxa. To compare the modelled response to climate change, we estimated migration speed between respective time periods using vector analysis.

   We found significant genetic congruence between valley oak and the lichen's green algal photobiont, independent of geographic isolation and habitat isolation, which is consistent with long‐term association. Ecological niche models under past and future climate scenarios indicate that overlap of climatic niche sharing between valley oak and lace lichen might decrease in the future. Our models indicate that the speed of shifts in climate niches between these two taxa differed significantly in past periods from that of the present period.

   Our findings reveal that historical interactions between valley oak and lace lichen correlate with long‐term sharing of past climate niches. However, the future association of lace lichen with valley oak may be disrupted in parts of its current distribution due to differential discordance of climate niche shifts, species’ movements and generation times. This study illustrates the processes and patterns that allow long‐term association during historic climate change and how they are likely to change during rapid climate change.

    

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3. Phylogeographic analysis of shrubby beardtongues reveals range expansions during the Last Glacial Maximum and implicates the Klamath Mountains as a hotspot for hybridization

   https://doi.org/10.1111/mec.15992  

   Stone, Benjamin W. ; Wolfe, Andrea D. ( June 2021 , Molecular Ecology)

   Quaternary glacial cycles often altered species' geographic distributions, which in turn altered the geographic structure of species' genetic diversity. In many cases, glacial expansion forced species in temperate climates to contract their ranges and reside in small pockets of suitable habitat (refugia), where they were likely to interact closely with other species, setting the stage for potential gene exchange. These introgression events, in turn, would have degraded species boundaries, making the inference of phylogenetic relationships challenging. Using high‐throughput sequence data, we employed a combination of species distribution models and hybridization tests to assess the effect of glaciation on the geographic distributions, phylogenetic relationships, and patterns of gene flow of five species ofPenstemonsubgenusDasanthera, long‐lived shrubby angiosperms distributed throughout the Pacific Northwest of North America. Surprisingly, we found that rather than reducing their ranges to small refugia, mostPenstemonsubgenusDasantheraspecies experienced increased suitable habitat during the Last Glacial Maximum relative to the present day. We also found substantial evidence for gene exchange between species, with the bulk of introgression events occurring in or near the Klamath Mountains of southwestern Oregon and northwestern California. Subsequently, our phylogenetic inference reveals blurred taxonomic boundaries in the Klamath Mountains, where introgression is most prevalent. Our results question the classical paradigm of temperate species' responses to glaciation and highlight the importance of contextualizing phylogenetic inference with species' histories of introgression.

    

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4. Occupancy patterns and upper range limits of lowland Bornean birds along an elevational gradient

   https://doi.org/10.1111/jbi.13691  

   Burner, Ryan C. ; Styring, Alison R. ; Rahman, Mustafa A. ; Sheldon, Frederick H. ( August 2019 , Journal of Biogeography)

   The traditional view of species’ distributions is that they are less abundant near the edges of their ranges and more abundant towards the centre. Testing this pattern is difficult because of the complexity of distributions across wide geographical areas. An alternative strategy, however, is to measure species’ distributional patterns along elevational gradients. We applied this strategy to examine whether lowland forest birds are indeed less common near their upper range limits on a Bornean mountain, and tested co‐occurrence patterns among species for potential causes of attenuation, including signatures of habitat selection and competition at the periphery of their ranges.

   Mt. Mulu, Borneo.

   Rain forest birds.

   We surveyed lowland forest birds on Mt. Mulu (2,376 m), classified their elevation‐occupancy distributions using Huisman–Olff–Fresco (HOF) models, and examined co‐occurrence patterns of species pairs for signatures of shared habitat patches and interspecific competition.

   For 39 of 50 common species, occupancy was highest at sea level then gradually declined near their upper range edges, in keeping with a “rare periphery” hypothesis. With respect to habitat selection, lowland species do not appear to cluster together at sites of patchy similar habitat near their upper range limits; neither are most lowland species segregated from potential montane competitors where ranges overlap.

   High relative abundance at sea level implies that species inhabit “truncated niches” and are not currently near the limits of their fundamental niche, unless unknown critical response thresholds exist. However, indirect effects of increasing temperature predicted under climate change scenarios could still influence lower range limits of lowland species indirectly by altering habitat, precipitation regimes and competitive interactions. The lack of non‐random co‐occurrence patterns implies that patchy habitat and simple pairwise species interactions are unlikely to be responsible for upper range limits in most species; diffuse competition across diverse rain forest bird communities could still play a role.

    

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5. Polyploidy in creosote bush ( Larrea tridentata ) shapes the biogeography of specialist herbivores

   https://doi.org/10.1111/jbi.13490  

   O'Connor, Timothy K. ; Laport, Robert G. ; Whiteman, Noah K. ( January 2019 , Journal of Biogeography)

   Whole‐genome duplication (polyploidy) can influence the biogeography and ecology of plants that differ in ploidy level (cytotype). Here, we address how two consequences of plant polyploidy (parapatry of cytotypes and altered species interactions) shape the biogeography of herbivorous insects.

   Warm deserts of North America.

   Gall midges (Asphondylia auripilagroup, Diptera: Cecidomyiidae) that attack three parapatric cytotypes of creosote bush (Larrea tridentata, Zygophyllaceae).

   We surveyedAsphondyliaspecies diversity at 177 sites across a 2300‐km extent. After noting a correspondence between the distributions of eightAsphondyliaspecies andL. tridentatacytotypes, we fine‐mappedAsphondyliaspecies range limits with transects spanning cytotype contact zones. We then tested whether plant–insect interactions and/or abiotic factors explain this coincidence by (a) comparing attack rates and gall midge communities on alternative cytotypes in a narrow zone of sympatry and (b) using species distribution models (SDMs) to determine if climatically suitable habitat for each midge species extended beyond cytotype contact zones.

   The range limits of 6/17Asphondyliaspecies (including two novel putative species confirmed withCOIsequencing) perfectly coincided with the contact zone of diploid and tetraploidL. tridentata. One midge species was restricted to diploid host plants while five were restricted to tetraploid and hexaploid host plants. Where diploid and tetraploidL. tridentataare sympatric, cytotype‐restricted midge species more frequently attacked their typical host andAsphondyliacommunity structure differed markedly between cytotypes.SDMs predicted that distributions of cytotype‐restricted midge species were not constrained by climatic conditions near cytotype contact zones.

   Contact zones between plant cytotypes are dispersal barriers for manyAsphondyliaspecies due to plant–insect interactions. The distribution ofL. tridentatacytotypes therefore shapes herbivore species ranges and herbivore community structure across North American deserts. Our results demonstrate that polyploidy in plants can affect the biogeography of ecological communities.

    

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