Ecosphere最新文献

Fungi play key roles in the fire-fuel feedbacks that structure ~40% of the Earth's terrestrial ecosystems, yet a general understanding of fungal responses to fire is lacking. While fire and associated stressor effects on fungi vary based on fire regime components like severity, intensity, and frequency, their influence on fungi can be categorized into three primary phases based on when they influence fungi: during fire, early post-fire, and later post-fire. We first identify key fire-associated phenomic traits and similarities in fungal responses to fire across time. Then, we synthesize this information by linking fire effects to specific fungal traits and response groups to produce trait profiles useful for classifying pyrophilic fungi. The goal of this review is to consolidate fire-associated phenomic trait data into trait profiles that can be used in combination with fungal genomic data and associated methodologies. These profiles produce an invaluable framework for understanding fungal roles in fire regimes and identify previously unknown trends in fungal responses to fire and associated stressors including heat shock responses, pigmentation, and dispersal into and out of burned environments.

Following the implementation of a camera trap-monitoring protocol of interactions between cave bats and wildlife in the Republic of Congo, we identified sustained rusty-spotted genet (Genetta maculata) activity in Boundou cave. This cave, consisting of a single chamber, is home to a colony of several species of insectivorous bats throughout the year. Between 2022 and 2023, we recorded four events of bat or rodent consumption, one hunting attempt on bats and three feeding behaviors on insects. We describe and discuss the various behaviors and briefly elaborate on the potential epidemiological implications of bat consumption. To the best of our knowledge, our videos are the first to depict the consumption of bats by rusty-spotted genets.

Identifying how species respond to system drivers such as weather, climate, habitat, and resource availability is critical for understanding population change. In coastal areas, the transfer of nutrients across the marine and terrestrial interface increases complexity. Nesting populations of bald eagles (Haliaeetus leucocephalus) along the Pacific coast of North America, although terrestrial, are largely dependent on marine resources during the breeding season and therefore represent a good focal species for understanding the linkages of nutrients between terrestrial and marine systems. Due to their location, coastal eagle populations are susceptible to a variety of climate-induced perturbations, from both land and sea. The northeast Pacific Marine Heatwave (PMH) of 2014–2016 had wide-ranging impacts on the marine ecosystem and provided an opportunity to explore how marine conditions can impact terrestrial wildlife populations. We used a spatially explicit multistate occupancy modeling framework to analyze >30 years of bald eagle nest occupancy data collected in four large national parks along a coastal interior gradient in Alaska, USA. We assessed occupancy state in relation to weather conditions, salmon abundance, access to alternate prey resources, and the PMH event to help elucidate the factors affecting bald eagle occupancy dynamics over time. We found that occupancy probability was higher in areas where prey resources were concentrated (e.g., near seabird colonies, where bears facilitate access to salmon carcasses). We also found that the probability of reproductive success was higher during warmer, drier springs with higher-than-average salmon abundance. After the onset of the PMH, success declined in the areas most dependent on non-salmon marine resources. These findings confirm the importance of spring weather conditions and access to salmon resources during the critical chick-rearing period, but also reveal that marine heatwaves may have important secondary effects through a reduction in the overall quantity or quality of prey available to bald eagles. Given ongoing warming at high latitudes and the expectation that marine heatwaves will become more common, our findings are useful for understanding ongoing and future changes in the transfer of nutrients from marine to terrestrial ecosystems and how such changes may impact terrestrial species such as bald eagles.

Ecosystems are frequently considered to be controlled by predation (top-down). Experiments examined this in four bird/spider/grasshopper/prairie habitats over 34 years, employing in each habitat three 100 m² bird exclosures and controls (121 habitat/year cases) where plant, grasshopper, and spider abundances were measured. Top-down control (plants decrease and grasshoppers increase with bird exclusion) was observed in only 13.2% of cases, while plants increased and grasshoppers decreased in 33.1% of cases, plants decreased and grasshoppers decreased in 25.6% of cases, and plants increased and grasshoppers increased in 28.1% of cases. Therefore, top-down control was not common and system responses were not constant, but varied among sites, years, and directionally over time with climate change. This diversity of responses is expected given the variety of underlying processes in complex ecosystems. For example, decision tree/discriminant analysis found that plant decreases and increases with bird exclusion were correctly identified in 78.3% of cases by grasshopper hatchling abundance, plant cover, and annual net primary production (ANPP), while grasshopper decreases and increases with bird exclusion were correctly identified in 76.7% of cases by edible plant biomass per grasshopper hatchling, grasshopper hatchling abundance, and large grasshopper abundance. Analysis of other system-wide terrestrial trophic experiments indicates that the variety of responses observed by us over time and space may be common so that system-wide trophic responses may, in general, be more variable than either top-down or bottom-up as often considered.

The debate over the best agricultural practices for biological conservation often focuses on the degree to which agricultural lands should be interspersed with desirable habitat versus protecting lands entirely from production. It is important to understand the benefits agriculture provides for wildlife because it is consuming an increasing proportion of the landscape. We evaluated the nesting ecology of breeding ducks within a mosaic of flood-irrigated conservation areas and agricultural lands in hay production. We assessed how habitat features at two spatial scales across these lands were related to nest site selection, nest density, and nest survival of multiple duck species. Birds selected nest sites with higher visual obstruction, a higher proportion of shrubs around the nest, and less bare ground, but we did not detect evidence of selection per se at larger spatial scales. Nest density was marginally higher along linear features, including irrigation ditches and riparian stretches, but nest survival remained similar across land-use types and habitats features. This system is representative of many agricultural landscapes around the globe and highlights the ways agroecosystems can be managed to maintain habitat suitability for wildlife on working lands.

Forest disturbances are expected to increase in severity with climate change and intensified land use, threatening future delivery of several ecosystem services, including the climate-mitigating potential of forests. Alleviating these consequences through adaptive forest management demands a greater understanding of what drives the impacts of disturbances on forests, which, in turn, requires collection of high-quality data through large-scale and long-term monitoring programs. The Swedish National Forest Inventory has been recording “damages” on living trees across a forest area of 230,000 km², in addition to a wide range of stand characteristics and environmental conditions. Using 15 years of these data, we investigated the frequency of different types of tree damages and the causes of these damages and modeled damage risk among tree species and across gradients in stand attributes and environmental conditions. We found that 94% of all surveyed trees had some type of damage, but for 65% of these, the underlying cause was not identified. Nevertheless, for all damage types and causes, we found that damage risk varied considerably among tree species and across gradients in tree species richness, tree height, and stand age. For a few damages, stand age or tree species richness interacted with climate to influence risks. Among identified causes of damage, “wind and snow” was most common (11.9% of surveyed trees), followed by “forestry” (6.9%). Further, for most causes of damage where stand age was significant, the risk was highest in young or the youngest stands. As such, our results indicate that there is great potential for reducing the risk of tree damages via adaptive management, such as altered tree species composition and increased rotation length. However, for a greater understanding of what is driving the frequency and magnitude of forest damages, and to be able to provide specific, useful information to stakeholders, collection of higher-quality data must be prioritized by monitoring programs.

To further evaluate the effect of water stress on soil respiration (R_S), reveal the influencing factors of daily and seasonal R_S, and systematically evaluate and compare the sensibility of different machine learning algorithms (multiple nonlinear regression [MNR], support vector machine regression [SVR], backpropagation artificial neural network [BPNN]) to estimate R_S from a maize field under water stress condition, the field experiments were conducted within a maize field in Inner Mongolia, China, during the entire 2019 growing season. Various levels of deficit irrigation were conducted in the vegetative, reproductive, and mature stages. Our research indicated that soil CO₂ fluxes from 100% evapotranspiration treatment (Tr1) were significantly greater than various deficit irrigation treatments (Tr2, Tr3, Tr4) during each growth stage of summer maize. The cumulative soil CO₂ fluxes of Tr2, Tr3, and Tr4 decreased 24.8%, 30.3%, and 43.7% compared with Tr1, respectively. We determined that the drivers affecting the daily R_S were soil temperature at 5 cm depth (T_S,5) and soil surface temperature (T_SF), followed by water-filled porosity (WFPS) at 5 cm depth, but no significant correlations were observed at 25 cm depths. T_S,5 and T_SF also performed similar correlation with seasonal R_S with R greater than 0.753 among all water treatments, followed by chlorophyll content with R greater than 0.726. During the whole growing season, the BPNN model exhibited the best predicting result, and could explain the 60%–80% and 87.8% of the variations of R_S at the daily and seasonal scales, with root mean square error of 48.7–100.9 mg m⁻² h⁻¹ and 91.5 mg m⁻² h⁻¹, respectively. The SVR and MNR models could estimate the 47.9%–57% and 39.9%–52.1% of the daily R_S and 81.4% and 78.6% of the seasonal R_S, respectively. Overall, our study indicated the machine learning algorithms could be successfully applied to estimate R_S at daily and seasonal scales from a maize field under water stress condition.

Resource availability can alter infection outcomes through its impact on host immunity and on parasite reproduction. On one hand, enhanced nutrition could favor immunity, limiting the parasite, and on the other hand, it could favor establishment and reproduction of the parasite. Our study aimed to determine the effect of diet on (1) host susceptibility to infection and (2) parasite production in a snail-trematode system. We fed Biomphalaria sudanica, a snail vector of Schistosoma mansoni, either a strict lettuce (low nutrient) or pellet (high nutrient) diet for two generations before exposing them to S. mansoni. We used two parasite strains, one that is incompatible with the snails and one that is compatible with the snails. We found that when exposed to incompatible parasites, diet did not affect snail susceptibility significantly as few snails were infected overall. However, when challenged with the compatible parasites, snails fed the high-nutrient diet were more susceptible to infection than their low-nutrient-fed counterparts. The high-nutrient-fed snails also produced more cercariae than low-nutrient-fed snails, but this advantage was lost after the initial assessment at 8 weeks. Snails that obtained infections were either kept on their initial diet or switched to the other diet. This experiment showed that snails switched from a low-to-high-nutrient diet produced more cercariae than those remaining on the low-nutrient diet and similar numbers to those remaining on the high-nutrient diet. Unexpectedly, the reciprocal diet switch (high to low nutrient) initially resulted in more cercariae relative to controls, but the pattern reversed after initial assessment. This study showed that available resources can impact the susceptibility of the vector host and the reproductive capacity of the parasites, with higher nutrients favoring parasite establishment and reproduction, highlighting the plasticity of susceptibility phenotypes, which also have a strong genetic basis. These data can aid predictions of how future environmental changes and resource availability may impact parasite transmission.

In forest management settings, disturbance resets forests to earlier successional stages, typically improving forage conditions for mule deer. Examining how forest disturbance influences mule deer behavior is important for guiding forest and wildlife management. We used GPS collar data collected between 2017 and 2019 from 136 adult female mule deer in three populations throughout western Montana, United States, to investigate how disturbance from burns (wildfire and prescribed fire) and timber harvest influenced three aspects of space-use behaviors: (1) probability of migration from winter range to summer range, (2) home range (second-order) selection by migrants on summer range, and (3) within-home range (third-order) selection. We hypothesized that deer would maximize use of disturbances during summer for nutritional benefits, predicting that deer with higher proportionate disturbance in their winter home range would be less likely to migrate away from those disturbances during summer. We predicted that migrants would select disturbances at the second and third orders. We found that proportionate disturbance in winter home ranges had no effect on the probability of migration. Among migrants, deer generally selected burns, timber harvests, and open-canopy habitat at the second order in all study areas, with particularly strong selection for 6- to 15-year-old disturbances. At population levels, selection for disturbances ceased at the third order. At individual levels, however, third-order selection for burns increased with availability, whereas selection for harvests decreased, suggesting burns may satisfy more resource needs than harvests. Our results emphasize how space-use fidelity constrains mule deer habitat selection. During summer, adherence to migratory strategies constrains the habitat available for second-order selection, preventing deer from exploiting disturbances that would otherwise be available had they remained resident in wintering areas. Second-order selection then determines disturbance availability within home ranges, affecting third-order behaviors. Although variance in selection behaviors among individuals was high, population-level patterns were remarkably similar among study areas, suggesting these responses may be generalizable to mule deer throughout the northern Rocky Mountains. Forest management practices like timber harvest, prescribed burns, and wildfire management within higher elevation areas of summer range used by migrants could yield the greatest nutritional benefits for mule deer.

A positive correlation between wealth and biodiversity within cities is a commonly documented phenomenon in urban ecology that has come to be labeled as the “luxury effect.” We contend that both this language and this framing restrict our understanding of how sociopolitical power dynamics influence biodiversity within and across cities. We describe how the term “luxury” is not appropriately applied to describe patterns of biodiversity and how the pattern depends on the form(s) of biodiversity investigated. While we recognize examples where there is a positive relationship between socioeconomic status and biodiversity, we describe numerous examples where either opposite patterns or no clear relationship between wealth and biodiversity is found. We propose an alternate framework, the POSE framework, that examines the Power, Objectives, mediating Socio-ecological context, and Effort of specific actors and how those may influence biodiversity. The mediating socio-ecological context includes everything from biophysical limitations to historical context and the actions of other actors. Further, it is important to understand how and to what degree we expect the actor's actions to influence biodiversity in order to design studies that are able to detect these shifts in biodiversity. We contend that complicating our analysis to focus more on power generally, rather than socioeconomic status specifically, as well as the specific objectives of actors of interest within their socio-ecological context offers a more flexible approach that can be applied in a wider range of socio-ecological contexts and allows for more directed policy interventions.