Ecological Research最新文献

The 10th International Conference on Serpentine Ecology was held in Nancy, France on 12–16 June, 2023. As a major international scientific forum in the field of serpentine (ultramafic) ecology, this conference brings together botanists, zoologists, microbiologists, physiologists, geneticists, geologists, soil scientists, and other applied specialists studying the ecology of ultramafic rocks and soil. A notable aspect of these meetings is the multidisciplinary nature of research on ultramafic biota, including diversity, ecology, evolution, physiology, and applied research in phytotechnologies and conservation. The main goals of the conference were to create a platform for the exchange of ideas and experiences and to promote scientific dialogue among scientists from numerous fields who share expertise in the study of ultramafic habitats worldwide. In this Special Issue we present the major topics and provide some highlights of the contributions to the 10th International Conference on Serpentine Ecology.

Acer mono is thought to comprise seven varieties, but its classification and nomenclature are controversial. A recent molecular phylogenetic study suggested that A. mono varieties glabrum (G) and mayrii (M) do not interbreed, despite occurring syntopically (same location) and having a common genetic origin. However, if these are separate, reproductively isolated species, the basis for that isolation remains unclear. Here, we tested whether G and M can be considered separate species that differ in multiple ecological characteristics. We compared G and M in terms of distribution, habitats, drought tolerance of leaves, and flowering phenology of trees, and we verified their reproductive isolation (RI) in Japan. G showed higher drought and salt tolerance than M, which is consistent with the distribution of G in salt-stressed coastal areas with relatively low precipitation. In contrast, M occurs in snowy, mesic, and mountain habitats. Even in neighboring M and G trees, the onset of flowering in M is earlier than that of G. Similarly, flower drop in M is completed sooner than in G. Although the presence of post-zygotic reproductive barriers was not tested, the high calculated RI index probably contributes to RI. Two varieties of A. mono with a common genetic origin but different drought tolerance should be considered separate species. They likely shifted their climatic niches, involving local adaptation to different climatic conditions. This is roughly supported by an ENM-based niche analysis and significant differences in flowering time. These findings help to understand the physiological diversification of A. mono.

Research on metal hyperaccumulating plants has concentrated on New Caledonia, Brazil, Cuba, the Mediterranean basin, and southeastern Asia, while other regions remain under studied. This work used a systematic approach in the targeted search for new hyperaccumulators in Mesoamerica, with a focus on characterizing nickel (Ni) hyperaccumulation in six species of Orthion and the monotypic genus Mayanaea (Violaceae), to complement earlier global studies on the related genus Hybanthus. We screened major herbarium collections, using x-ray fluorescence (XRF) analysis to measure metal concentrations in specimens of Orthion and Mayanaea ranging from Mexico to Nicaragua. In addition, fresh samples collected in Mexico were analyzed with associated rhizosphere soils. The results indicated that all species of Orthion and Mayanaea are able to hyperaccumulate Ni. Ni concentration ranges in leaves of herbarium specimens were (in mg kg⁻¹ dry weight): Orthion guatemalense (380–5100), O. malpighiifolium (24–5620), O. montanum (1620–5850), O. oblanceolatum (60–1440), O. subsessile (450–18,700), and O. veracruzense (22–3660). The available specimen of Mayanaea caudata had foliar Ni concentration of 5390 mg kg⁻¹. Field-collected samples of O. veracruzense and O. subsessile had similar Ni concentrations to herbarium specimens. Additionally, many Orthion species were facultative hyperaccumulators of cobalt. This is the first report of Ni hyperaccumulation in Violaceae from the Western Hemisphere. Ni hyperaccumulation in Orthion and Mayanaea is consistent with published phylogenies showing that they belong to a clade which also includes strong hyperaccumulators in the genus Hybanthus from Australia and New Caledonia. Orthion subsessile has suitable traits to become a potential crop for agromining of Ni.

The flora of New Caledonia is renowned as one of the world's most significant biodiversity hotpots. The contrasting soil conditions that characterize this small archipelago profoundly influence species local diversity and distribution. Because the difference between soil chemistry is likely to cause variation in leaf elemental composition, we wanted to test how different soil properties affect plant community and leaf elemental concentration. We focused on two adjacent forests, of similar physiognomy, growing on serpentinite (ultramafic rock), and on volcano-sedimentary rock. Both soils strongly differed in their pH, cation exchange capacity, and element concentration (Al, Mn, and Ni). The two adjacent forests have a diverse endemic flora and share a relatively high proportion of species (35%–42%). The tree composition differs more than the total vascular flora. Leaf element concentrations of 30 tree species that grow on both soil types, as well as the corresponding soil–plant-available nutrients, were analyzed. Leaf element concentrations indicated N, P, K, and Ca deficiency. Despite higher plant-available Mn concentration in ultramafic soil than volcano-sedimentary soil, leaf Mn concentrations were significantly higher for plants growing on volcano-sedimentary soil. Leaf Ni concentrations were higher on ultramafic soil and Al concentration was higher on volcano-sedimentary soil. Major differences in leaf elemental concentration were for micronutrients (metals) while macronutrients varied in much lower proportion between the two soil types, suggesting a tight regulation of macronutrients compared to micronutrients.

Animal collective behavior produces group-level patterns that emerge from individual-level interactions among members. Such sophisticated behavioral coordination can be observed across various taxa, indicating evolutionary convergence. Among the most striking examples are two social insect lineages: ants and termites. Ants and termites evolved socially independently, inhabit terrestrial and subterranean environments, and face a similar collective task of maintaining their colonies with many individuals. This results in the convergent evolution of collective phenomena, such as constructing complex nest structures or movement coordination based on chemical and tactile cues. However, although the striking similarity attracts the most attention, little research has focused on how ants and termites differ in collective behaviors at individual and group levels. Here, we review the similarities and distinctions of collective behaviors in ants and termites. Even with similarities in group-level patterns, rich diversity exists in mechanisms of behavioral coordination and the functions of collective patterns. Comparative analysis of collective behavior is challenging, but recent advances in automatic movement tracking methodologies have greatly expanded the potential for generating further insights. Finally, we conclude that comparative collective behavioral analysis can enhance our ability to understand biodiversity and provide alternative solutions for collective problem-solving in many fields.

Many animal species have movement abilities. Behavior is important for evolutionary ecology because animal movement leads to dispersal, migration, search for food and mates, and escaping from enemies. However, individual differences in movement activity are found within a population. This phenomenon can be affected by various factors, one of which is suggesting that higher moving activity has fitness cost, whereas lower moving activity has benefits. Animal movement may also affect reproduction (e.g., resource allocation tradeoff between movement and reproduction as well as intra- and intersexual selection). Although many previous studies have investigated the relationship between movement and reproduction, less attention has been paid to walking movement. In this study, previous studies that investigated the relationship between movement and reproduction were reviewed using the flour beetle Tribolium castaneum, a model insect in behavioral ecology and genetics. Several previous studies suggest that beetle walking is strongly associated with male and female reproductive traits. In recent years, empirical studies on the correlation between walking and other traits have increased, particularly in T. castaneum. Although this species can fly and walk, the movement is often discussed without discriminating between flight and walk. Differences in modes of movement may affect the correlation between movement and other traits; thus, discussing each mode of movement separately is necessary.

The use of x-ray fluorescence (XRF) instruments for metallome analysis of herbarium specimens to discover hyperaccumulator plant species has gained popularity, but a growing concern arises about intercomparability from the use of different instrument makes and models. Therefore, this study aimed to assess the performance and comparability of the results generated by three different XRF instruments and three different quantification methods (empirical calibration based on XRF versus inductively coupled plasma atomic emission spectroscopy [ICP-AES] regression, in-built manufacturer algorithms, and an independent GeoPIXE software pipeline based on Fundamental Parameters). Three instruments with distinct specifications were chosen to improve the generalizability of the results, ensuring relevance to a wide range of instruments that may be used in the future for metallome analysis of herbarium specimens. Each instrument was used to scan a representative set of dried hyperaccumulator plant leaf samples, and their accuracy in quantifying elemental concentrations was then compared. The manufacturer algorithms overestimate the elemental concentrations and have the highest errors. The empirical calibrations have the closest mean concentration to the mean concentrations reported by ICP-AES, but can produce negative values. The independent pipeline performance is marginally better than the empirical calibration, but it takes substantially more time and effort to setup the Fundamental Parameters through reverse engineering the instrument hardware parameters. Using the GeoPIXE independent pipeline to extract the XRF peak intensity to use in the empirical calibration performs better than manufacturer algorithms, while avoiding the complicated setup requirements, and this should be considered for further development.

While diverse animal species have been implicated in epizoochorous seed dispersal, studies specifically focused on bird-mediated seed dispersal are scarce. We evaluated the potential contribution of two terrestrial birds, green pheasant (Phasianus versicolor) and Chinese bamboo partridge (Bambusicola thoracicus), to epizoochorous seed dispersal using a dummy-based method. Furthermore, we compared the number of seeds attached to birds and mammals using data from a previous study conducted using the same method, site, and season. The results revealed 435 seeds of four herbaceous species (Achyranthes bidentata, Hylodesmum podocarpum, Oplismenus undulatifolius, and Persicaria filiformis) attached to two bird dummies. All seeds found on birds possessed adhesive appendages such as hooks, bristles, or viscous substances. In addition, the number of attached seeds does not exhibit significant differences between birds and mammals, irrespective of the season or plant species. Our findings provide the first documented evidence of epizoochorous seed dispersal by Phasianidae birds, highlighting the potential redundancy and complementarity between birds and mammals in mediating epizoochory.