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The effect of environmental change in structuring the phytoplankton communities of the coastal waters of the Eastern English Channel was investigated by applying a trait-based approach on two decades (1996-2019) of monitoring on diatoms and Phaeocystis . We show that phytoplankton species richness in an unbalanced nutrient supply context was influenced by wind-driven processes, ecological specialization for dissolved inorganic phosphorous, temporal niche differentiation, and a competition-defense and/or a growth-defense trade-off, a coexistence mechanism where weak competitors (i.e., slower growing) are better protected against predation. Under the influence of both environmental perturbations (e.g., wind-driven processes, freshwater influence, unbalanced nutrient levels) and biotic interactions (e.g., competition, predation, facilitation), phytoplankton species exhibited specific survival strategies such as investment on growth, adaptation and tolerance of species to environmental stresses, silicification and resource specialization. These strategies have led to more speciose communities, higher productivity, functional redundancy and stability in the last decade. Our results revealed that the unbalanced nutrient reduction facilitated Phaeocystis blooms and that anthropogenic climate warming and nitrate reduction may threaten the diatom communities of the eastern English Channel in a near future. Our results provide strong support for biogeographical historical and niche-based processes in structuring the phytoplankton community in this temperate region. The variety of species responses that we characterized in this region may help to better understand future changes in pelagic ecosystems, and can serve as a basis to consider functional approaches for future ecosystem management.

AIM: Emerging infectious diseases present a major perturbation with apparent direct effects such as reduced population density, extirpation and/or extinction. Comparatively less is known about the potential indirect effects of disease that likely alter community structure and larger ecosystem function. Since 2006, white‐nose syndrome (WNS) has resulted in the loss of over 6 million hibernating bats in eastern North America. Considerable evidence exists concerning niche partitioning in sympatric bat species in this region, and the unprecedented, rapid decline in multiple species following WNS may provide an opportunity to observe a dramatic restructuring of the bat community. LOCATION: We conducted our study at Fort Drum Army Installation in Jefferson and Lewis counties, New York, USA, where WNS first impacted extant bat species in winter 2007–2008. METHODS: Acoustical monitoring during 2003–2011 allowed us to test the hypothesis that spatial and temporal niche partitioning by bats was relaxed post‐WNS. RESULTS: We detected nine bat species pre‐ and post‐WNS. Activity for most bat species declined post‐WNS. Dramatic post‐WNS declines in activity of little brown bat (Myotis lucifugus, MYLU), formerly the most abundant bat species in the region, were associated with complex, often species‐specific responses by other species that generally favoured increased spatial and temporal overlap with MYLU. MAIN CONCLUSIONS: In addition to the obvious direct effects of disease on bat populations and activity levels, our results provide evidence that disease can have cascading indirect effects on community structure. Recent occurrence of WNS in North America, combined with multiple existing stressors, is resulting in dramatic shifts in temporal and spatial niche partitioning within bat communities. These changes might influence long‐term population viability of some bat species as well as broader scale ecosystem structure and function.

Exploitative competition and interference competition differ in the way access to resources is modulated by a competitor. Exploitative competition implies resource depletion and usually produces spatial segregation, while interference competition is independent from resource availability and can result in temporal niche partitioning. Our aim is to infer the presence of spatial or temporal niche partitioning on a two-species system of terrestrial salamanders in Northern Italy: Speleomantes strinatii and Salamandrina perspicillata. We conducted 3 repeated surveys on 26 plots in spring 2018, on a sampling site where both species are present. We modelled count data with N-mixture models accounting for directional interactions on both abundance and detection process. In this way we were able to disentangle the effect of competitive interaction on the spatial scale, i.e., local abundance, and from the temporal scale, i.e., surface activity. We found strong evidence supporting the presence of temporal niche partitioning, consistent with interference competition. At the same time, no evidence of spatial segregation has been observed.

1. In studies of an organism's functional ecology, key behavioural traits such as foraging periodicity are assumed to be uniform across the species. In particular, the fundamental division between diurnal and nocturnal activity patterns is usually assumed to be a fixed one, with organisms demonstrating physiological traits optimised for a particular diel rhythm. 2. In this study, we explore the activity rhythm of a tropical reef fish, the golden-lined rabbitfish, Siganus lineatus. We make use of acoustic telemetry (manual tracking), combined with underwater observations of feeding behaviour to investigate the diel foraging patterns of S. lineatus, at three sites around the lagoon of Lizard Island, Great Barrier Reef. 3. We found significant differences in the activity patterns of shoreline and reef-based populations of S. lineatus. Individuals inhabiting the boulder-shoreline site foraged during the day and remained stationary in rest holes during the night, whereas individuals from the two reef populations foraged only during nocturnal hours, remaining stationary at the edge of favoured coral bommies during the day. To our knowledge, this represents the first example of a wholesale intraspecific shift in diel activity rhythm for a tropical marine fish. 4. We suggest that S. lineatus is a diurnal nominal herbivore whose biological rhythm has developed the flexibility to be nocturnal. This development may simply represent the masking effects of predation, competition or ontogeny, or it may represent entrainment over an evolutionary time-scale necessary to enable the species to expand its range into the coral reef environment. 5. Either way, the results identify S. lineatus as a potential subject for research into the relative importance of the various biological forces driving divisions along the temporal niche axis and suggest that the species has the potential to provide insights into the impact of biological rhythm plasticity on ecosystem functioning at the ecological and evolutionary level.

Odonata, like most freshwater invertebrates, tend to overwinter in water due to the thermal properties of a water environment. Winter damselflies (genus Sympecma ), however, hibernate as adults in terrestrial habitats. The strategy of adult overwintering combined with high mortality is associated with several unique adaptations to semiarid conditions, but winter damselflies maintain this unique life history throughout almost the entire Palaearctic. We assume that the unique strategy of adult overwintering in temperate zones is indirectly maintained by niche separation in time. We used phenological data from the Czech Republic to compare the seasonal phenology of Sympecma spp. with other coexisting odonate species. Seasonal population growth patterns between S. fusca and other coexisting species representing different life histories were compared using GLMMs and LME. The models showed negative non-linear dependence between the population growth of S. fusca and the estimated abundance of compared species. We found that the specific strategy of adult overwintering makes it possible to avoid seasonal maxima of competition and predation in adult and larval stages. Adults may benefit from free niches during spring while larvae may benefit from size advantage among intraguild competitors and optimal conditions for development.

A venerable generalization about community resistance to invasions is that more diverse communities are more resistant to invasion. However, results of experimental and observational studies often conflict, leading to vigorous debate about the mechanistic importance of diversity in determining invasion success in the field, as well as other ecosystem properties, such as productivity and stability. In this study, we employed both field experiments and observational approaches to assess the effects of diversity on the invasion of a subtidal marine invertebrate community by three species of nonindigenous ascidians (sea squirts). In experimentally assembled communities, decreasing native diversity increased the survival and final percent cover of invaders, whereas the abundance of individual species had no effect on these measures of invasion success. Increasing native diversity also decreased the availability of open space, the limiting resource in this system, by buffering against fluctuations in the cover of individual species. This occurred because temporal patterns of abundance differed among species, so space was most consistently and completely occupied when more species were present. When we held diversity constant, but manipulated resource availability, we found that the settlement and recruitment of new invaders dramatically increased with increasing availability of open space. This suggests that the effect of diversity on invasion success is largely due to its effects on resource (space) availability. Apart from invasion resistance, the increased temporal stability found in more diverse communities may itself be considered an enhancement of ecosystem function. In field surveys, we found a strong negative correlation between native-species richness and the number and frequency of nonnative invaders at the scale of both a single quadrat (25 x 25 cm, and an entire site (50 x 50 m). Such a pattern suggests that the means by which diversity affects invasion resistance in our experiments is important in determining the distribution of invasive species in the field. Further synthesis of mechanistic and observational approaches should be encouraged, as this will increase our understanding of the conditions under which diversity does (and does not) play an important role in determining the distribution of invaders in the field.

The introduced parasitoid wasp Aphytis melinus , the most widespread natural enemy of the California red scale ( Aonidiella aurantii ) and the superior competitor, has displaced the native Aphytis chrysomphali from most citrus areas of the Mediterranean basin and other citrus areas all over the world. However, our extensive survey data on the scale parasitoid populations collected in 2004-2008 show that in large citrus areas of eastern Spain both parasitoids coexist. Using field data from 179 orchards spatially divided in five citrus-producing agroecosystems, we examined the mechanisms that could explain displacement or coexistence between both Aphytis species in relation to weather conditions. The distribution and abundance of the parasitoid species are related to the mean summer and winter temperatures and relative humidity of each ecosystem. The relative proportion of A. melinus is higher during the warm months, and the abundance of A. chrysomphali increases from south to north, being higher in the cooler northern areas. Aphytis melinus has displaced A. chrysomphali from hot and dry areas, whereas regions with mild summer temperatures and moderate relative humidity present the optimal conditions for the coexistence of the two parasitoids. The more negative effects of winter temperatures on A. melinus allow the earlier use of the available host resource in late winter and spring by A. chrysomphali and the coexistence of both parasitoids in the same orchard via temporal niche partitioning. We combine previous literature on the behavior of Aphytis species in the laboratory under different temperature and humidity conditions with our field results to confirm the role of spatiotemporal weather conditions and seasonal changes in host stages on the variation of Aphytis relative abundance and parasitoid coexistence.

食肉目（Carnivora）动物对维持食物网稳定和生态系统功能平衡具有重要作用，理解捕食者与其猎物的时间生态位有助于珍稀物种的保护。为探究豹猫（Prionailurus bengalensis）与同域分布潜在猎物的日活动特征、季节性变化和种间活动重叠规律，于2018年9月—2020年8月在甘肃兴隆山国家级自然保护区布设60台红外相机开展持续监测，累计工作日33 521 d，共捕获豹猫370次、灰尾兔（Lepus oiostolus） 390次、鼠类（Rats）760次和环颈雉（Phasianus colchicus）834次独立有效事件。基于核密度曲线和活动重叠度分析豹猫、灰尾兔、鼠类和环颈雉的日活动节律，揭示捕食者与猎物在青草期和枯草期的日活动节律变化模式。结果显示：（1）豹猫和鼠类的日活动节律为双峰型夜行性，环颈雉为持续峰型昼行性，而灰尾兔表现为峦峰型泛夜行性。（2）除环颈雉外，其他3个物种日活动节律季节性变化明显，枯草期均倾向于凌晨活动，且豹猫也增加了白天午后的活动时长，具有较强的适应性。（3）豹猫与鼠类、灰尾兔的重叠度较高，但存在季节差异，青草期与鼠类重叠度最高（∆4=0.779），枯草期与灰尾兔重叠度最高（∆1=0.720），与环颈雉青草期（∆4=0.356）和枯草期（∆1=0.453）重叠度均最低。本研究从时间维度评估了豹猫与其猎物的活动行为响应，为探讨兴隆山豹猫与猎物的时空共存机制和为自然保护地开展关键物种保护与有害物种防治提供科学依据。

Temporal niche partitioning can be a viable mechanism for coexistence, but has received less attention than other niche axes. We characterized and compared patterns of activity, and overlap of temporal activity among the five common rodent species from a tropical semideciduous forest (TSF) and between the two common rodent species from cloud forest (CF) at El Cielo Biosphere Reserve in Mexico. Capture frequencies over 2-h intervals, obtained via live trapping (6850 trap-nights) in chosen months over 3 y formed the empirical basis for analyses. Trap transects were set from 19h00 to 07h00 and checked every 2 h. Analyses of 484 captures evinced two distinct assemblages. The TSF assemblage was diverse and with non-random temporal niche segregation, whereas the CF assemblage was depauperate with its two dominant species evincing the same activity pattern. Predator avoidance between open- and closed-microhabitat species, as well as niche complementarity may explain temporal segregation at TSF. This is the first documentation of assemblage-wide non-random temporal segregation of neotropical rodents. Time of activity may be a largely under-appreciated mechanism in other species-rich tropical rodent assemblages as well as in other species-rich biotas.