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Phenological trends among Australian Alpine species: Using Herbarium records to identify climate-change indicators

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Global temperatures are increasing at an unprecedented rate and the analysis of long-term phenological records has provided some of the most compelling evidence for the effect of these changes on species. In regions where systematically collected data on the timing of life-cycle events is scarce, such as Australia, researchers must seek alternative sources of information from which climate-change signals can be identified. In the present paper, we explore the limitations and strengths of using herbarium specimens to detect changes in flowering phenology, to select potential indicator species, and to pinpoint locations for potential monitoring schemes of native plants in Australia's subalpine and alpine zone. We selected 20 species on the basis of a range of selection criteria, including a flowering duration of 3 months or less and the number of herbarium records available in the areas above 1500 m. By the use of gridded temperature data within the study region, we identified an increase in mean annual temperature of 0.74 C between 1950 and 2007. We then matched the spatial locations of the herbarium specimens to these temperature data and, by using linear regression models, identified five species whose flowering response may be sensitive to temperature. Higher mean annual temperatures at the point of collection were negatively associated with earlier flowering in each of these species (a = 0.05). We also found a significant (P = 0.02) negative relationship between year and flowering observation for Alpine groundsel, Senecio pectinatus var. major. This species is potentially a suitable candidate for monitoring responses of species to future climate change, owing to the accessibility of populations and its conspicuous flowers. It is also likely that with ongoing warming the other four species identified (Colobanthus affinis, Ewartia nubigena, Prasophyllum tadgellianum and Wahlenbergia ceracea) in the present study may show the same response.
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... Lima et al. (2021) found that climate change has caused inconsistent patterns in flowering and fruiting times across different species. Calinger et al. (2013) and Gallagher and Leishman (2009) found that the increase in temperature caused by climate change has caused plants to flower at an earlier date. Pearson (2019) found that spring flowering species flowered 1.8 -2.3 days earlier per 1℃ increase in spring temperatures. ...
... Many studies have hypothesized that climate change would cause some species of plants to start flowering at an earlier date. This prediction has been supported by various studies, but others have indicated that flowering times of plants can be delayed (Calinger et al. 2013;Gallagher and Leishman 2009;Pearson 2019;Sherry et al. 2011). Species' distributions are based on biotic and abiotic factors. ...
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Climate change has resulted in various changes to the phenology of species, and some of these changes have been documented through the use of herbarium specimens. Understanding how plants react to changes in the environment can give scientists insight into how plants have been responding and will respond to the continuing consequences of climate change as well as how to approach biodiversity conservation. In this study, herbarium records of Collinsia violacea Nutt. ranging from 1895 to 2014 were utilized to show the trends of the first and peak flowering dates with regard to various geographic and climatic variables using regression analysis. The results from simple linear regression analyses showed a trend of the flowering times for first and peak flowering dates occurring earlier over the years; however, the relationship was not significant. The multiple linear regression full model for first flowering indicated increases in latitude, longitude, and mean monthly temperatures were associated with delayed flowering while increases in monthly minimum and maximum temperatures were associated with earlier flowering. The full model for peak flowering showed that peak flowering was delayed with increases in latitude, longitude, and maximum monthly temperature. The reduced models, with highly correlated variables removed, indicated significant delays in first flowering and peak flowering with increases in latitude, longitude, and mean monthly temperature, but no significant relationship between monthly precipitation and flowering time. Further research is needed to fully understand the implications of these changes.
... Herbarium-based phenological studies are invaluable for understanding the effects of climate change on plant species [1][2][3][4][5][6][7][8]. These studies leverage the extensive historical records provided by herbarium specimens, which have shown congruence with ield observations, effectively assessing patterns and mechanisms of plant phenological responses [6,9]. ...
... Herbarium-based phenological studies are invaluable for understanding the effects of climate change on plant species [1][2][3][4][5][6][7][8]. These studies leverage the extensive historical records provided by herbarium specimens, which have shown congruence with ield observations, effectively assessing patterns and mechanisms of plant phenological responses [6,9]. ...
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Herbarium records provide a valuable historical database for assessing plant phenology shifts in the context of global climate change. The herbarium specimens, collected from diverse locations and periods, offer comprehensive data illustrating how many plants are altering their blooming times in response to global climate change. The appropriate use and analysis of long-term herbarium records offer an additional dimension for the study of plant phenology through the application of advanced experimental methodologies such as bioinformatics and satellite imagery, statistics, and Artificial Intelligence (AI) which, coupled with field observations, will improve ecosystems evaluation. These efforts can significantly contribute to conservation strategies and climate change mitigation and further support the synchronization of scientific inputs for evaluating the impacts of climate change and its ecological implications.
... Phenotypic plasticity with varying floral traits across altitudinal gradients is reported in Swertia thomsonii [23]. Gallagher et al. [24], using herbarium records, reported an Australian alpine species as a climate change indicator, mentioning conspicuous flowering patterns and accessible population making the species suitable for monitoring responses toward future climate, which is also suitably depicted in S. bimaculata. While studying the tropical ecosystem Numata et al. [25] emphasized on improved mechanistic understanding of environmental drivers of reproductive phenology in diverse species to decipher complex phenological responses. ...
... Phenotypic plasticity with varying floral traits across altitudinal gradients is reported in Swertia thomsonii [23]. Gallagher et al. [24], using herbarium records, reported an Australian alpine species as a climate change indicator, mentioning conspicuous flowering patterns and accessible population making the species suitable for monitoring responses toward future climate, which is also suitably depicted in S. bimaculata. While studying the tropical ecosystem Numata et al. [25] emphasized on improved mechanistic understanding of environmental drivers of reproductive phenology in diverse species to decipher complex phenological responses. ...
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... Floral richness is one measure that provides an important yardstick on the fitness of Alpine wildflowers, as meadow species are generally perennial (Roslin et al., 2021). Furthermore, flowers are good indicators for measuring the effects of climate change (Dreyer et al., 2006;Gallagher et al., 2009;Miller-Rushing et al., 2008;Rawal et al., 2015). Studying montane meadows provides insights into ecosystem dynamics, plant and animal adaptations and climate change effects (Duan et al., 2021;Jiang et al., 2018;Stöcklin et al., 2009). ...
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... In recent decades, herbaria collection shave transcended their classical role, becoming a dynamic tool in ecological studies. Herbaria collections now serve as historical records of biodiversity, offering information about species distribution, population dynamics, and ecological preferences, as well as response to climate change, which poses a severe threat to our water resources Gallagher et al., 2009;Jones & Daehler, 2018). The convergence of traditional herbarium techniques with modern technologies, such as digitization, molecular analysis, and geographical information systems (GIS), has created unprecedented research opportunities, particularly in biodiversity monitoring and conservation. ...
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Herbaria collections—systematic repositories where plant specimens are preserved—are transitioning from traditional taxonomic tools into fundamental resources in ecological research. This comprehensive review summarizes multidisciplinary applications of herbaria collections in monitoring biodiversity and conservation. The review evaluates the historical and contemporary importance of herbaria specimens in documenting changes in species distribution, population dynamics, and community composition, elucidating their roles in understanding the effects of climate change and human intervention. Moreover, it examines how herbaria collections contribute to large- scale temporal and spatial biodiversity analyses, predictive modeling, and conservation planning in the context of advancements in digitization and molecular techniques. This review underscores the integration of herbaria data into mainstream ecological research and policy decisions, advocating for modernizing herbarium techniques and the innovative use of collections. It aims to foster a deeper understanding of complex environmental systems and inform targeted conservation strategies by revealing the multifaceted uses and expectations of herbaria in ecological studies. Thus, it contributes to the broader scientific discussion on sustainable biodiversity management and highlights the relationship between herbaria and ecological studies.
... Similarly, using 216 herbarium specimens, Lavoie and Lachance [71] reported (15-31 days) earlier flowering of Tussilago farfara L.in the twenty-first century than in around 1920. Several herbarium-based studies report earlier flowering in different plants [12,42,72]. The early-spring-flowering species of bluebell, cuckoo flower, coltsfoot, garlic mustard, and wood anemone responded to increasing temperatures by advancing their first flowering day (FFD) [73]. ...
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... Floral richness is one measure that provides an important yardstick on the fitness of Alpine wildflowers, as meadow species are generally perennial (Roslin et al., 2021). Furthermore, flowers are good indicators for measuring the effects of climate change (Dreyer et al., 2006;Gallagher et al., 2009;Miller-Rushing et al., 2008;Rawal et al., 2015). Studying montane meadows provides insights into ecosystem dynamics, plant and animal adaptations and climate change effects (Duan et al., 2021;Jiang et al., 2018;Stöcklin et al., 2009). ...
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