Climate Change Ecology最新文献

Environmental change often causes decreased food availability and/or increased foraging costs, putting wild animals at risk of starvation. Body-fat reserves can enable individuals to resist (buffer) periods of weather-driven food scarcity, improving their chances of survival and subsequent reproductive success. This capacity, however, is constrained by life-history factors and fixed long-term differences between individuals. Here, we use 29 years of data from a population of wild European badgers (Meles meles) to test how weather and population density affect individual body condition indices (BCIs), how BCI mediates survival rate and reproductive success, and whether long-term BCI phenotypes (fat vs. thin) provide life-history advantages. Maintaining body condition above a certain threshold was key to survival (reflecting a nonlinear relationship), especially when temperatures varied more between seasons (requiring greater tactical foraging and BCI adjustments) and following excessive rainfall (causing thermoregulative stress). BCI also affected survival more strongly in older individuals. Female reproductive success increased linearly with autumn BCI, and consistently fatter badgers (of both sexes) had higher lifetime reproductive success; however, substantial intra-individual body-condition variation remained after accounting for weather and individual factors, and 84% of individuals varied BCI substantially from year to year. Modelling BCI responses according to projected climate change through 2080 (Emissions Scenario RCP 8.5) revealed that even strong warming (as one-off events) would produce < 5% survival probability reductions, pushing few individuals below the BCI risk threshold. We thus demonstrate that life-history factors and individual body-condition tactics are fundamental to understanding population resilience under anthropogenic climate change.

Shifting flowering seasons is a global effect of climate change that can have important long-term evolutionary and demographic effects on plant communities. Life history optimization theory can be a valuable tool to assert the adaptive value and fitness effects of observed phenological shifts, but takes plant-plant competition rarely into account. Here we combine energy allocation models with evolutionary game theory to assess how size-asymmetric competition for light can influence phenological adaptations and fitness responses to a changing climate – here represented as changes of the start, end and intensity of the growing season. We focus on annual plants which, due to their short generation times, are particularly likely to exhibit rapid demographic and evolutionary responses to environmental change. We find that while light competition favors late flowering times, it does not affect the direction of selection in the climate changes scenarios considered here. We predict, however, that plants adapted to light competition face more detrimental fitness consequences if the growing season advances, becomes shorter or less intense. We also show that adaptation to changing growing seasons under light competition can favor increased investment in vegetative growth with the counterintuitive side effect that seed production is reduced at the same time. In sum, our study highlights several effects of light competition that may help to interpret phenological trends and idiosyncratic fitness effects of climate change in wild plant communities.

The Galapagos Islands are one of the most productive marine ecosystems in the world. The convergence of four ocean currents and the isolation of these islands create a variety of ecosystems that host unique biodiversity. Many of the endemic species are particularly vulnerable to disturbances in their environment, as most of them are unable to migrate or adapt in response to changing climatic conditions. Due to climate change, there is an increase in extreme weather patterns (El Niño-Southern Oscillation [ENSO] and La Niña events) and climate variability. These affect the productivity of marine and terrestrial ecosystems on the Galapagos Islands and ultimately disrupt natural processes and ecosystem dynamics. Here we conduct a systematic review on the impact on the increase of extreme weather events (ENSO and La Niña events) and climate variability on the biodiversity of the Galapagos Islands. We demonstrate that the increase in the frequency of ENSO events poses a major threat to endemic marine biodiversity, while it has positive impacts on many terrestrial species due to increase rainfall and food availability. In contrast, La Niña provides sometimes positive conditions for marine species allowing them to recover, while for many terrestrial species La Niña years result in worse conditions causing adverse effects. Therefore, the increased frequency of ENSO and La Niña years under climate change poses significant threats to the Galapagos biodiversity. Also, increased climate variability (not related to ENSO and La Niña events) has adverse impacts on marine and terrestrial species, putting biodiversity under even more pressure. The results of our review are key to understand the far-reaching implications of climate change on the Galapagos Islands and can be used to understand impacts on other archipelagos worldwide, which are often areas with high levels of (endemic) biodiversity.

Black locust (Robinia pseudoacacia L.) has been widely used to restore degraded land in northern China for many decades, and the forest has become an important ecosystem in China. However, there is still knowledge gap about how the range shift of black locust in response to future climate change, which is the first step for adaptive management of black locust. Here, a global niche model of black locust was established by means of maximum entropy model (MaxEnt), 1174 global occurrences data, as well as 13 climatic variables. Then, the global niche model was projected to China under current climate (2000) and four future climate scenarios (2080). The results showed that the range of black locust is mainly controlled by temperature related variables rather than precipitation related variables. The latitude of potential range of black locust is mainly between 23° and 40° in China with the area of occupation being about 26.7% (25.7 × 10⁵ km²) of China's total land area. Future climate is conducive to the northward expansion of black locust in China with a speed of 21 km/decade, as well as an upward shift with a speed of 9.6 m/decade across climate scenarios. Relatively high stable ranges (87–94%) and quick range shift speed implies that little vulnerability of black locust in response to climate change, as well as little risk of extinction in China.

Coastal deoxygenation is poorly documented in the tropics. When the Isthmus of Panama separated the Caribbean from the Pacific, sister lineages diverged and adapted to changing oxy-thermal conditions along both coasts. This provides unique insight into the ecological consequences of ocean warming and deoxygenation. We find deoxygenated, or hypoxic, waters shoal to the shallow depths of 10 m on both sides of the Isthmus, with Caribbean waters generally warmer than those in the Pacific. We tested the performance of two Caribbean Echinometra sea urchin species and their Pacific sister species under different warming and oxygen scenarios. Performance, measured as righting ability, was reduced by 50–100% under hypoxia compared to normoxia in one species from each coast. Only one Caribbean species performed well under hypoxia and did so at ambient temperatures (≤ 29 °C) but not under warming. This tolerant species, E. viridis, appears to be specialized for living on protected Caribbean reefs, unlike its two sister species that occur on well-oxygenated reefs. Our results emphasize the danger of shoaling hypoxia compressing well-oxygenated habitat from beneath and the importance of evolved hypoxia tolerance. This highlights the underappreciated risk deoxygenation poses for shallow tropical ecosystems.

Phenological matching between the timing of flowering and pollinator activity is critically important for the persistence of pollination systems globally. Phenological mismatch between plants and their insect pollinators can occur if flowering and adult insect activity do not occur simultaneously. There is evidence that the phenological trajectories vary among bee species, but little has been done to compare these trajectories with the phenology of the corresponding floral community. In this work, we use daily pan trapping across nine different annual Clarkia (Onagraceae) plant communities that vary in Clarkia species composition to estimate the phenological trajectory (within-season abundance curve) of the two most abundant bee pollinators - Lasioglossum incompletum, a generalist, and Hesperapis regularis, a Clarkia specialist - over the course of a Clarkia flowering season in California USA. Clarkia flower at the end of the winter annual growing season when all other winter annual plants have senesced, and therefore are phenologically separate from other flowering plants. We find that Hesperapis pollinator abundances follow the same phenological trajectory as Clarkia floral abundances in all community types. In contrast, Lasioglossum abundances do not track Clarkia floral abundance through time. Our results demonstrate that Clarkia exhibit closer phenological matching with Hesperapis than with Lasioglossum. These findings imply that pollinator communities may not respond monolithically to changes in the environment. Future research should study the phenological trajectories of plants and pollinators in different systems to determine if this pattern is common and repeatable.

Sargassum mats in Mexican bays reduce the biodiversity of coral and seagrass nursery habitats. Three bays in Quintana Roo, Mexico were chosen to determine the environmental stress caused by Sargassum natans and S. fluitans on coral, seagrass and fish populations. For both control sites, Yal Ku Lagoon and Half Moon Bay with little to zero Sargassum cover, benthic communities and the physico chemical characteristics of the waters were not impacted. In Soliman Bay, Sargassum mats cover large areas in the shallows and shore and smother the seagrass and corals. Under the Sargassum mats light and dissolved oxygen levels were significantly lower. Anoxic conditions were found, with levels as low as 0.5 mg/L for oxygen and a 73% decrease in light. Water temperature was 5.2 ± 0.1 °C (mean ± SE) warmer under the Sargassum mats. By determination of weight (grams per day) and growth (mm per day), the stress caused by Sargassum mats in Soliman Bay caused a seven-fold decrease in productivity of T. testudinum compared to other sites. Taxonomic diversity was also reduced with lower biomass and an altered species distribution. To improve these ecosystems, pre-emptive conservation management and protection must be priority for future ecosystem health and biodiversity.

Biofilms harbour a wealth of microbial diversity and fulfil key functions in coastal marine ecosystems. Elevated carbon dioxide (CO₂) conditions affect the structure and function of biofilm communities, yet the ecological patterns that underpin these effects remain unknown. We used high-throughput sequencing of the 16S and 18S rRNA genes to investigate the effect of elevated CO₂ on the early successional stages of prokaryotic and eukaryotic biofilms at a CO₂ seep system off Shikine Island, Japan. Elevated CO₂ profoundly affected biofilm community composition throughout the early stages of succession, leading to greater compositional homogeneity between replicates and the proliferation of the potentially harmful algae Prymnesium sp. and Biddulphia biddulphiana. Species turnover was the main driver of differences between communities in reference and high CO₂ conditions, rather than differences in richness or evenness. Our study indicates that species turnover is the primary ecological pattern that underpins the effect of elevated CO₂ on both prokaryotic and eukaryotic components of biofilm communities, indicating that elevated CO₂ conditions represent a distinct niche selecting for a distinct cohort of organisms without the loss of species richness.

Specific proximate mechanisms as climate spatial fluctuations modify the pattern of synchronic reproduction (masting) or seed production at population level in the Fagus genus worldwide. However, phenological processes as mass flowering, beechnut development and seed rain have attracted attention to understand the masting behavior in relict-endangered tree species. The normalized difference vegetation index (NDVI), temperature and precipitation could act as proxy signals resembling the onset of mast-seeding events. We studied a masting event in 2017 in ten relict-endangered Mexican beech forests (Fagus grandifolia subsp. mexicana) in eastern Mexican montane cloud forests. Our aims were 1) test if NDVI shows a particular pattern before and after masting event in 2017 at 10 sites; 2) explore how monthly temperature and precipitation change two years before and during the masting across the Mexican beech forests; and 3) assess how the beechnut amount and quality was affected by spatial and temporal specific climatic variables in the recorded masting event among the beech forests. We found that the masting was related to the canopy greenness variation (2015–2018) in the beech forests. Nut production variability among beech forests was related to temperature and precipitation fluctuations. We found that maximum and mean temperature and high precipitation during May to August were decisive to trigger the synchronic Mexican beech masting spatial behavior.

Future water temperature changes may have a profound impact on fish-parasite interactions. However, while the effect of temperature on fish, and particularly salmonids, is well-understood, its combined effects with parasitic exposure are not. Here, we use a multi-stage experimental approach to explore the impact of increased water temperatures consistent with persistent climate change-induced warming and extreme thermal fluctuations from hydropower (thermopeaking) on brown trout alevins and fry before and during exposure to Saprolegnia parasitica. Parasite exposure had the strongest and most significant effect on survival of both host life stages. The combination of parasite exposure, thermal pre-conditioning and the ongoing thermal regime had a weak but significant influence on alevin mortality. Both parasite-exposed alevin and fry experienced increased mortality when a constant increase in temperature was combined with intermittent thermal increases. The outcomes of this experimental approach provide the basis for future studies scaling up the potential impacts of temperatures and parasite exposure that key fish species may face in the wild. They also highlight the effects of anthropogenic changes on brown trout populations, as pressures on aquatic organisms are likely to intensify in future climate scenarios with increased hydropower development and thermopeaking, particularly in the presence of pathogens.