Affect Ecosystem Processes Research Articles

Dynamic feedbacks among tree functional traits, termite populations and deadwood turnover

Abstract Changes in the composition of plant functional traits may affect ecosystem processes through influencing trophic interactions. Bottom‐up control by plant species through food availability to animals may vary with time. However, such dynamics and their consequences for deadwood turnover are poorly known for detrital food webs. We introduce a dynamic conceptual model of the feedback of tree functional traits, (deadwood‐feeding) termite populations and deadwood decomposition. We hypothesized that tree functional diversity (in terms of a wood resource economic spectrum [WES]) supports the sustenance of termite populations via complementary food supplied through time, as deadwood varies in traits both initially across species and because of different decomposition rates. Simultaneously, driven by this temporal dynamics of food quality, the consumption of deadwood by termites should hypothetically sustain deadwood turnover in a functionally diverse forest over time. We tested our hypothesis through an 18‐month termite‐exclusion decomposition experiment by incubating coarse (i.e. 5 cm diameter) deadwood of 34 woody species in two subtropical forests in East China. One site still sustained a healthy population of pangolins as the keystone termite predator, whereas another had lost its pangolins due to hunting and illegal wildlife trade. The results supported our hypothesis: in the first 12 months, termites amplified the positive linear relationship between % wood mass loss and initial wood quality (WES). In contrast, between 12 and 18 months, termite‐mediated consumption, and associated wood mass loss, showed a humpback relation with the initial WES. This shift in termite preference of deadwood species along the WES reflects complementary food availability to termites through time. Synthesis. Our findings imply that tree functional composition, with variation in deadwood quality through decomposition time, can help to sustain termite populations and thereby forest carbon turnover. Future studies need to test whether and how our conceptual model may apply to other detrital systems and food webs. In general, food web research would benefit from a stronger focus on temporal patterns for better understanding the interactions of basal resource functional traits and consumers on ecosystem functions.

Winter Habitat Indices (WHIs) for the contiguous US and their relationship with winter bird diversity

The seasonal dynamics of snow cover strongly affect ecosystem processes and winter habitat, making them an important driver of terrestrial biodiversity patterns. Snow cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra satellites can capture these dynamics over large spatiotemporal scales, allowing for the development of indices with specific application in ecological research and predicting biodiversity. Here, our primary objective was to derive winter habitat indices (WHIs) from MODIS that quantify snow season length, snow cover variability, and the prevalence of frozen ground without snow as a proxy for subnivium conditions. We calculated the WHIs for the full snow year (Aug-Jul) and winter months (Dec-Feb) across the contiguous US from 2003/04 to 2017/18 and validated them with ground-based data from 797 meteorological stations. To demonstrate the potential of the WHIs for biodiversity assessments, we modeled their relationships with winter bird species richness derived from eBird observations. The WHIs had clear spatial patterns reflecting both altitudinal and latitudinal gradients in snow cover. Snow season length was generally longer at higher latitudes and elevations, while snow cover variability and frozen ground without snow were highest across low elevations of the mid latitudes. Variability in the WHIs was largely driven by elevation in the West and by latitude in the East. Snow season length and frozen ground without snow were most accurately mapped, and had correlations with station data across all years of 0.91 and 0.85, respectively. Snow cover variability was accurately mapped for winter (r = 0.79), but not for the full snow year (r = −0.21). The model containing all three WHIs used to predict winter bird species richness patterns across the contiguous US was by far the best, demonstrating the individual value of each index. Regions with longer snow seasons generally supported fewer species. Species richness increased steadily up to moderate levels of snow cover variability and frozen ground without snow, after which it steeply declined. Our results show that the MODIS WHIs accurately characterized unique gradients of snow cover dynamics and provided important information on winter habitat conditions for birds, highlighting their potential for ecological research and conservation planning.

Linking macrophyte community structure with food chain length: A case study in the largest freshwater lake in China and ecological restoration implications

Food chain length is a significant ecosystem index and it greatly affects ecosystem processes and their outcomes. In recent decades, determinants or indicators of FCL have been investigated in different ecological contexts, but few studies analyzed the relationships between macrophyte community structure and the food chain length of freshwater ecosystems despite the crucial role of macrophyte community in determining food web structure. This study investigated the influence of macrophyte community structure on food chain length by conducting a field survey in Lake Poyang, the largest freshwater lake in China. Plant volume inhabited (PVI), Shannon-Wiener diversity index and Pielou’s evenness index were used to indicate macrophyte community structure. Our results suggested that intermediate levels of PVI and diversity (PVI 44% and diversity 0.61) with greater evenness could support longer food chain in sub-lakes of Lake Poyang. We proposed that macrophyte community structure indexes could be useful indicators in indicating food chain length in freshwater ecosystem. These novel findings also highlight that within suitable ranges of PVI and diversity, better restoration effect could be achieved by higher macrophyte evenness in lake management. Our findings provide new insights for the restoration and management of macrophytes in freshwater ecosystems.

Ain’t No Mountain Pine Enough: A Case Study of How Mountain Pine Beetles are Affecting Ecosystem Processes

This case study engages students in generating hypotheses and predictions, analyzing and interpreting data, critically evaluating contrasting results in science, and thinking about feedbacks between biota and abiotic ecosystem dynamics. To address these areas, students use primary literature and simulated data about the interactions between mountain pine beetles and terrestrial carbon cycling. Mountain pine beetles are causing unprecedented mortality in forests in the mountain west, serving as a particularly relevant issue for our students in Colorado. The case is designed for three 50-minute class periods or two 75-minute class periods and should be implemented after students have learned the basics of terrestrial carbon cycling. During implementation of this case in a lower-division ecology course, we found that 1) content knowledge increased for most questions regarding student comprehension of carbon cycling, 2) students were better able to identify reasons for contrasting scientific results beyond scientist bias or human error, and 3) including a narrative in the assignment did not increase student perceptions of topic relevance. <em>Primary image:&nbsp;</em>Mountain Pine Beetle Kill in the Gore Range, Colorado. Forest with trees that have been attacked by the mountain pine beetle, in front of mountains in the Gore Range in Colorado. Photo by Dr. Jeff Mitton, reprinted with written permission.

Influence of the chlorophyll-a gradient on the community structure of plankton microcrustaceans (Cladocera and Copepoda) in a Neotropical reservoir.

Fish farming in net cages is considered as an alternative to food production in response to elevated population growth, and zooplankton is an important resource to the development of this economic activity. We (i) compared microcrustacean composition in eutrophic and oligotrophic habitats under net tank influence, (ii) investigated changes in species distributions in these habitats, and (iii) indicated which chlorophyll-a concentrations presented thresholds that alter community structure. We expected different responses of species to changes in chlorophyll-a concentration due to net cage management, as chlorophyll-a represents an estimate of food availability. Microcrustacean samplings and chlorophyll-a estimation were made upstream, downstream and close to the net cages, during 120 days, in the Rosana Reservoir (Brazil). Species composition differed significantly (p<0.05) among habitats where in the eutrophic environment was found the largest number of species. However, only in the eutrophic habitats did frequency of occurrence and relative abundance of some species change with chlorophyll-a variation. Thus, net cage management influenced species distribution only in the most productive habitat. These responses can affect ecosystem processes related to trophic dynamics as secondary productivity and nutrient cycling.

Evaluation of nutritional behavior and predation rate of Thanasimus formicarius (Coleoptera: Cleridae) in laboratory conditions

Bark beetle is one of the most dangerous groups among forest pests. Periodic outbreaks of these species can cause very serious economic losses as well as negatively affect ecosystem processes and functions. Strategies developed in line with the specific objectives and continued efforts to control these pests are necessary. Environment-friendly and nature compatible methods are preferred to keep the population of pests at low levels. One of the effective methods of suppressing the bark beetle population is biological control. Thanasimus formicarius, a general predator of many bark beetle species, is an effective natural enemy of them. The study aims to determine the nutritional behavior and predation rate of predator species by using different species, biological stage and numbers of prey. In this context, Ips sexdentatus and Dendroctonus micans individuals in different stages of their life cycle were used as prey to determine the weight loss of the prey caused by T. formicarius, prey preference, and predation rates of predator beetle. T. formicarius adults caused an average weight loss of 0.0188 g of their prey within 24 h. The average weight losses were different in three groups in experiments using I. sexdentatus adults alone, D. micans larvae alone, and these two species together as prey. In experiments wherein only I. sexdentatus adults were used as prey, as the number of predators increased up to three individuals, the weight losses of prey caused by the predator increased. In the evaluations conducted without considering the differences in stages of life cycle and prey species, the predator caught the prey at a rate of 69%. In experiments wherein only I. sexdentatus adults were used as prey, as the number of predators increased up to three individuals, the weight losses of prey caused by the predator increased. Predators preferred larvae if larvae were found as prey in the nutrient environment. The average predation rate of T. formicarius in experiments using I. sexdentatus adults alone as prey was 68.9%, whereas this rate was 71.3% in experiments using D. micans larvae alone.

A genomic catalog of Earth\u2019s microbiomes

The reconstruction of bacterial and archaeal genomes from shotgun metagenomes has enabled insights into the ecology and evolution of environmental and host-associated microbiomes. Here we applied this approach to >10,000 metagenomes collected from diverse habitats covering all of Earth’s continents and oceans, including metagenomes from human and animal hosts, engineered environments, and natural and agricultural soils, to capture extant microbial, metabolic and functional potential. This comprehensive catalog includes 52,515 metagenome-assembled genomes representing 12,556 novel candidate species-level operational taxonomic units spanning 135 phyla. The catalog expands the known phylogenetic diversity of bacteria and archaea by 44% and is broadly available for streamlined comparative analyses, interactive exploration, metabolic modeling and bulk download. We demonstrate the utility of this collection for understanding secondary-metabolite biosynthetic potential and for resolving thousands of new host linkages to uncultivated viruses. This resource underscores the value of genome-centric approaches for revealing genomic properties of uncultivated microorganisms that affect ecosystem processes.

The millennium shift: Investigating the relationship between environment and growth trends of Norway spruce and Scots pine in northern Europe

For boreal forests in colder climates, changes in environmental conditions are hypothesised to substantially affect ecosystem processes. In this study, trends of top height growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) were analysed using permanent sample plot data from more than 300 long-term experimental sites distributed from temperate zones to the boreal forest conditions in Sweden. By regression analyses, the effects of temperature-sum and precipitation-sum on top height growth were assessed in the period 1986–2018. A significant upward temporal trend in height growth was observed for both species, with the trend more pronounced after the millennium shift. The magnitude of the annual relative height growth after the millennium was about 16.92% and 9.54% higher than expected, respectively for Scots pine and Norway spruce. A potential climate response on height growth was found for both species with temperature-sum positively correlated with top height growth. No significant effect of precipitation-sum on height growth was observed for either species. Our results suggest improved growing conditions and forest sites became more productive in response to increasing temperature in the northern temperate and boreal regions. The increasing growth trends may offer shorter rotation periods and increased forest value for Norway spruce and Scots pine, coupled with contributions of boreal forests to the emerging bio-economy and the regulation of global atmospheric carbon.

Responses of arbuscular mycorrhizal fungi to nitrogen addition: A meta-analysis.

Arbuscular mycorrhizal (AM) fungi play important roles in carbon (C), nitrogen (N) and phosphorus (P) cycling of terrestrial ecosystems. The impact of increasing N deposition on AM fungi will inevitably affect ecosystem processes. However, generalizable patterns of how N deposition affects AM fungi remains poorly understood. Here we conducted a global-scale meta-analysis from 94 publications and 101 sites to investigate the responses of AM fungi to N addition, including abundance in both intra-radical (host roots) and extra-radical portion (soil), richness and diversity. We also explored the mechanisms of N addition affecting AM fungi by the trait-based guilds method. Results showed that N addition significantly decreased AM fungal overall abundance (-8.0%). However, the response of abundance in intra-radical portion was not consistent with that in extra-radical portion: root colonization decreased (-11.6%) significantly, whereas extra-radical hyphae length density did not change significantly. Different AM fungal guilds showed different responses to N addition: both the abundance (spore density) and relative abundance of the rhizophilic guild decreased significantly under N addition (-29.8% and -12.0%, respectively), while the abundance and relative abundance of the edaphophilic guild had insignificant response to N addition. Such inconsistent responses of rhizophilic and edaphophilic guilds were mainly moderated by the change of soil pH and the response of root biomass, respectively. Moreover, N addition had an insignificant negative effect on AM fungal richness and diversity, which was strongly related with the relative availability of soil P (i.e. soil available N/P ratio). Collectively, this meta-analysis highlights that considering trait-based AM fungal guilds, soil P availability and host plant C allocation can greatly improve our understanding of the nuanced dynamics of AM fungal communities under increasing N deposition.

Ecological legacies of past human activities in Amazonian forests.

SummaryIn Amazonia, human activities that occurred hundreds of years ago in the pre‐European era can leave long‐lasting effects on the forests – termed ecological legacies. These legacies include the intentional or nonintentional enrichment or depletion of certain species. The persistence of these legacies through time varies by species, and creates complex long‐term trajectories of post‐disturbance succession that affect ecosystem processes for hundreds of years. Most of our knowledge of Amazonian biodiversity and carbon storage comes from a series of several hundred forest plots, and we only know the disturbance history of four of them. More empirical data are needed to determine the degree to which past human activities and their ecological legacies affect our current understanding of Amazonian forest ecology.

Eco-physiological processes are more sensitive to simulated N deposition in leguminous forbs than non-leguminous forbs in an alpine meadow of the Qinghai-Tibetan Plateau

Increased nitrogen (N) deposition can affect ecosystem processes and thus influence plant eco-physiological processes in grasslands. However, how N deposition affects eco-physiological processes of leguminous and non-leguminous forbs in alpine grasslands is understudied. A long-term field experiment using a range of simulated N deposition rates (0, 8, 24, 40, 56, and 72 kg N ha−1 year−1) was established to examine the effects of N deposition on various eco-physiological parameters in leguminous and non-leguminous forbs in an alpine meadow of the Qinghai-Tibetan Plateau. We found that the responses of leguminous and non-leguminous forbs to simulated N deposition varied. Net photosynthetic rate of leguminous and non-leguminous forbs exhibited different response patterns, but chronic increases in simulated N deposition rates may lead to negative effects in both functional groups. Neither functional group responded differently in aboveground biomass under the highest N addition level (72 kg N ha−1 year−1) compared to the control. Differences in aboveground biomass of leguminous forbs were observed at intermediate N levels. Short-term simulated N deposition significantly promoted N uptake of both functional groups. In leguminous forbs, simulated N deposition affected net photosynthetic rates (PN) and aboveground biomass (AGB) mainly via stomatal conductance (gs), water use efficiency (WUE), and plant N uptake. In non-leguminous forbs, simulated N deposition affected PN and AGB mainly through WUE and plant N uptake. Our findings suggest that leguminous and non-leguminous forbs have differential response mechanisms to N deposition, and compared with non-leguminous forbs, leguminous forbs are more sensitive to continuing increased N deposition. The obvious decline trend in photosynthetic capacity in leguminous forbs is likely to exacerbate the already divergent ecological processes between leguminous and non-leguminous forbs. More importantly, these changes are likely to alter the future composition, function, and stability of alpine meadow ecosystems.

DNA metabarcoding reveals the responses of prokaryotes and eukaryotes microbiota to warming: Are the patterns similar between taxonomic and trophic groups?

Abstract The aquatic microbiota is involved in crucial ecosystem functions. Thus, investigating the effects of global warming on these organisms is highly relevant, especially given the numerous climatic changes expected by the end of the century. In this study, we used an experimental approach and high-throughput sequencing to evaluate the shortterm effect of warming predicted by different future scenarios in the composition of the planktonic freshwater bacteria and microeukaryotes, and to verify if the same effects occur for each trophic level separately (autotrophic, heterotrophic and mixotrophic). Our experiment demonstrated that the composition for eukaryotes and prokaryotes based on DNA metabarcoding is affected by the increase in temperature and these have a similar pattern of response to warming. This highlights the temperature importance in structuring the communities of different groups. Modifications in the communities were observed through the substitution of specific taxa, which occurred mainly in warmer levels. Changes in community composition were also identified when trophic levels were assessed separately. Mixotrophic eukaryotes organisms are more sensitive to warming, modifying the patterns of composition with an increase in temperature of 2 °C. Microeukaryotes and heterotrophic bacteria were more resistant, with alterations in the communities composition visualized only in higher warming levels. The composition of autotrophic organisms was not affected by the increase in water temperature in any of the biological classifications evaluated, although the richness of eukaryotic autotrophic has decreased with warming. Our results contribute to predict how different biological levels and trophic groups of the aquatic microbiota respond to global warming. This approach is relevant because warming leads to changes in community composition and affects ecosystem processes essentials to the aquatic environment.

Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems

Over the last century, anthropogenic activities have increased nitrogen (N) deposition considerably, which significantly affects ecosystem processes and has the potential to induce N saturation in the future. The continuous increase in N deposition may cause a non-linear response in soil respiration (Rs), an important component of carbon (C) cycling. However, little is known about N saturation threshold of soil respiration. In this study, we conducted coordinated experiments in four grassland types across northern China with four N addition levels to explore patterns in the Rs saturation threshold. Our results showed that an Rs saturation threshold generally exists in grassland ecosystems in response to N addition gradients. The N saturation threshold of Rs occurred at an average rate of 50 kg N ha−1 yr−1, but varied widely with grassland type; the N saturation threshold occurred at rates of 100, 50, 50, and 25 kg N ha−1 yr−1 in the alpine meadow, meadow steppe, typical steppe, and desert steppe, respectively. Autotrophic respiration (Ra) and heterotrophic respiration (Rh) responded to N addition gradients differently. Ra increased initially and became saturated at a rate of 50 kg N ha−1 yr−1 and declined thereafter. In contrast, Rh decreased monotonically after N addition. Structural equation models further confirmed that the effects of N addition gradients on Rs were primarily determined by the non-linear response of belowground biomass. Interestingly, the compiled global dataset showed that the N saturation threshold of Rs increased with precipitation and soil moisture. These findings indicate that the stimulating effect of N deposition on Rs and Ra might diminish with increasing N deposition in the future, especially in dry grassland ecosystems.

Prospects for Integrating Disturbances, Biodiversity and Ecosystem Functioning Using Microbial Systems

Biodiversity is a key driver of ecosystem functioning, while disturbances are a key driver of biodiversity. Consequently, disturbances crucially influence ecosystem functioning—both directly via affecting ecosystem processes but also indirectly via altering biodiversity. We thus need to disclose the joint relationships between disturbances, biodiversity and functioning (DBF) to understand and predict ecosystem dynamics under realistic conditions. However, biodiversity responses to disturbances have so far insufficiently been studied together with biodiversity effects on functions. For many ecosystems, such integrative exploration of DBF relationships would require too extensive manipulations and observations over unfeasible spatial and temporal scales. We argue that microbial systems offer a bright perspective to overcome these limitations, and present a roadmap for doing so. Microbial systems allow us exposing different, well-characterized communities to multiple, reproducible disturbance regimes and precisely measuring both biodiversity and associated functions over time. Comprehensive data can be obtained by systematically varying and replicating representative environmental scenarios. These data can further be explored and explained with computational models. Microbial systems thus reveal mechanisms that underlie DBF relationships and allow scrutinizing ecological hypotheses. This advancement of theory will be essential for ecology as a whole. It is particularly relevant in the context of global change, which is expected to promote disturbances as well as loss of biodiversity and functions in many ecosystems.

Exotic pine forestation shifts carbon accumulation to litter detritus and wood along a broad precipitation gradient in Patagonia, Argentina

Carbon dioxide emissions to the atmosphere from human activity continue to increase, and accordingly, strategies of biological carbon (C) sequestration in terrestrial ecosystems have been proposed. Forestation projects have garnered wide public support, and research has focused principally on how soil C storage is affected. Nevertheless, our mechanistic understanding of how forestation, particularly with exotic woody species, affects ecosystem processes is not well understood. We took advantage of a land-use change in Patagonia, Argentina, that involved the simultaneous planting of a single conifer species (Pinus ponderosa) along a broad precipitation gradient [250–2200 mm mean annual precipitation (MAP)], replacing natural ecosystems from semi-arid steppe to broadleaf forest. Comparing C fluxes and stocks in five paired natural and planted forest sites during three consecutive years demonstrated that aboveground net primary production (ANPP) was consistently greater in forested areas along the gradient, while litter decomposition markedly decreased. Dramatic increases in leaf litter detritus, coupled with increased aboveground woody biomass, contributed to identical levels of C accumulation in pine plantations from 250 mm to 1350 mm MAP, without significantly detectable differences in surface soil C. The replacement of intact forest in the most humid site resulted in large decreases in vegetation C pools. The implications for ecosystem C cycling suggest that inhibition of C turnover, along with the aboveground woody growth, are key variables contributing to the observed patterns of C accumulation from exotic pine forestation along this precipitation gradient. Given the transient nature of these C stocks, vulnerable to loss as CO2 due to climatic or anthropogenic disturbances, these changes may not contribute to long-term C sequestration in these ecosystems. The conversion of natural ecosystems as a management tool for C mitigation should include a consideration of the realized sequestration potential but also the unintended consequences for changes in both C inputs and C turnover that determine the ecosystem C balance, as well as potential effects on biodiversity and long-term ecosystem functioning.

Fire dynamics in Mato Grosso State, Brazil: the relative roles of gross primary productivity

ABSTRACTThe fires and biomass burning are responsible for affect ecosystem processes in a wide range of biomes at regional and global scales. In Brazil, the state of Mato Grosso is one of the most affected by the occurrence of forest fires. Thus, this study aims to quantify the long-term changes in the temporal and spatial patterns of fire occurrence and their effect on gross primary productivity (GPP) in the state of Mato Grosso, Brazil, considering the biomes that compose it. The images used in the study were acquired by satellite Terra and Aqua combined in the product MCD64A1.006, a monthly resolution of 500m by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, during the period from 01/10/2000 to 12/31/2018. The MOD17A2 product derived from the MODIS sensor provides the accumulated value of GPP. The points without the presence of burning presented higher values of GPP for all studied biomes. In some points with the presence of burning the GPP even decreased by 44.20%, 30.04% and 55.78% for Amazonia, Cerrado, and Pantanal, respectively. According to the results presented here, it is concluded that the burnings negatively impact gross primary production in the biomes of the state of Mato Grosso, Brazil and the dynamics of the burns do not keep up with the intensity of drought years. The use of cluster analysis techniques, such as principal component analysis (PCA), is an alternative to bigdata analysis when the objective is to evaluate the presence of forest burning in more than one biome.

Evaluating two sampling methodologies for shrimp density and biomass estimates in streams

Abstract Freshwater shrimp can reach high biomasses, affecting ecosystem processes. It is important to define the most accurate methodology to estimate their densities and biomass. We studied two species of different sizes, Potimirim brasiliana Villalobos F., 1960 and Macrobrachium olfersii (Wiegmann, 1836), in three sites of a coastal stream in Ilha Grande, Rio de Janeiro, Brazil. We evaluated the efficiency of two infrequently used sampling methods: a depletion method using electrofishing, and a substrate method using benthic samplers. The methodologies provided different estimates, especially for M. olfersii, of density (electrofishing 1.27 ± 6.3 ind/m²; substrate sampling 0.1 ± 5.05 ind/m²) and biomass (electrofishing 1.66 ± 8.5 g/m²; substrate sampling 0.11 ± 1.16 g/m²). The median size of M. olfersii was higher for electrofishing, while the median size of P. brasiliana was higher for substrate sampling. Electrofishing is good at collecting bigger individuals that are not possible to catch with the substrate method and it samples a bigger area that includes many different microhabitats. The substrate method is cost-effective, especially for P. brasiliana, but by sampling a small area, its estimates can be highly affected by local heterogeneity. The substrate method is not recommended for M. olfersii, as it underestimated both its density and biomass.

Litter microbial respiration and enzymatic resistance to drought stress

Many ecosystems are experiencing an increase in drought conditions as a consequence of climate warming and changing precipitation patterns. The stress imposed by these environmental changes can affect ecosystem processes such as the extracellular enzymatic degradation of carbon-containing leaf litter by soil microbial communities. However, the magnitude of these impacts may depend on the composition and metabolism of the microbial community. Based on the hypothesis of local adaptation, microbial communities native to warm-dry ecosystems should display a greater capacity to degrade leaf litter polymers with extracellular enzymes following exposure to warm-dry conditions. To test this hypothesis, we performed a microcosm study in which we monitored extracellular enzyme activity and respiration of microbial communities from five ecosystems along a southern California climate gradient, ranging from warmer, drier desert to wetter, cooler subalpine forest. To simulate drought and rewetting, we subjected microcosms to periods of high temperature and low moisture followed by a water pulse. We found that enzyme activity of wet-cool communities generally exceeded that of warm-dry communities across enzyme types for the five sites we considered. Additionally, we observed a significant decrease in respiration for all communities after longer durations of drought exposure. Although these findings did not align with our expectations of local adaptation, they suggest litter-inhabiting microbial communities are able to retain metabolic functioning in environmental conditions different from those of their native ecosystems. These results may imply that factors such as litter chemistry impose greater constraints than climate on community metabolic function. Overall, despite differences in local climates, microbial communities from semiarid regions may be metabolically adapted to maintain functioning in the face of drought.

Ecological Characteristics of Atlantic Forest Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae) in the State of Santa Catarina, Southern Brazil

Dung beetles are insects involved in the organic matter cycle, providing services in ecosystem functions through their feeding and reproductive behavior. Environmental degradation of the Atlantic Forest in Brazil causes a decrease in species richness, which may affect ecosystem processes. However, many of the characteristics related to the ecological functions of dung beetle species remains unknown. Our study aimed to describe the ecological characteristics of dung beetle species that inhabit the natural forest environments of Santa Catarina state, southern Brazil. We used databases from research conducted from 2007 through 2014 coupled with standardized sampling methods to capture copro-necrophagous Scarabaeinae in 103 native Atlantic forest areas in 20 locations in the state of Santa Catarina. The 98 species collected, representing six tribes and 20 genera, were identified, photographed to scale and categorized according to their feeding habit, resource allocation behavior, diel activity, relative abundance, body size, and distribution range in the state. Most of the species were of small size (n = 54) and tunnelers (n = 47), and almost half of the species (n = 42) were found only in one site, while 85 species were considered rare in relative abundance. In addition to contributing to the knowledge of dung beetle ecology in Brazil's Atlantic Forest, this study shows the species distribution in the region and highlights the importance of remaining forest fragments in the maintenance of biodiversity and the ecosystem functions carried out by these beetles.

Notes on the Nest Architecture and Colony Composition in Winter of the Yellow-Legged Asian Hornet, Vespa velutina Lepeletier 1836 (Hym.: Vespidae), in Its Introduced Habitat in Galicia (NW Spain)

Fifteen years ago, at least one multimated female yellow-legged Asian hornet (Vespa velutina Lepeletier 1836) arrived in France, giving rise to a pan-European invasion, altering the environment, affecting ecosystem processes, and impacting society. During winter, V. velutina nests (n = 3) were collected in Galicia and data on internal and external aspects of the nests and the colony as a whole were collected. The whole colony population (WCPN; adult insects, larvae, and pupae in percentages) was as follows: nest A: n = 176 (49%, 3%, and 48%); nest B: n = 1979 (52%, 36%, and 12%); and nest C: n = 662 (5%, 27%, and 8%). The adult insect population (IAPN; males, workers, and gynes in percentages) was as follows: nest A: n = 87 (11%, 66%, and 23%); nest B: n = 1021 (3%, 62%, and 35%); and nest C: n = 430 (20%, 73%, and 7%). As a small number of queens is sufficient for a population to develop, it is necessary to avoid continued spread by deactivating and removing all nests, even those detected in winter. This practice can be of greatest importance in border areas where V. velutina is expanding into new territory.