Indicators Of Ecosystem Health Research Articles

Marine coastal biodiversity and services in Ireland in a three-dimensional context: Scientific, news media, and legislative

Biodiversity is a key indicator of ecosystem health and plays an important role in providing ecosystem services that are essential for economic development and social well-being. In Ireland, climate change and anthropogenic pressures have led to biodiversity loss and habitat degradation, which in turn affects the provision of ecosystem services. The aim of this study was to determine how marine coastal biodiversity and ecosystem services in the Republic of Ireland are portrayed in the scientific literature, news media, and current legislation in order to identify knowledge gaps and priority areas of intervention for policymakers and other decision-making stakeholders. A review of the scientific literature based on the Scopus database suggests a lack of stakeholder involvement in the scientific-based approach. Up to 2022 research on marine coastal biodiversity focused primarily on species richness and diversity, especially in the context of climate change, while research on ecosystem services focused primarily on ecosystem function. Analysis of the news media found that coverage of biodiversity and ecosystem services has increased over the past decade, but opportunities are being missed to raise public awareness of the multiple benefits, not just economic, of marine coastal ecosystems, their biodiversity, and the services they provide. The terms “biodiversity” and “ecosystem services” have only been introduced into Irish legislation in recent years. The legislative context at the national level is rather fragmented at diverse levels and mainly corresponds to the transposition of European Directives while national specific legislation is less developed. The interconnection between these three domains: scientific, news media and legislative was not evident in this study, especially in the case of the scientific field. Efforts to promote science-based knowledge, communication, collaboration, and transparency between these domains are crucial to support informed decision-making and promote public engagement while conserving biodiversity. Addressing the information gaps identified in this work could help advance the implementation of Nature-based Solutions (NbS), key cost-effective measures to mitigate and adapt to the impacts of climate change while protecting biodiversity and ecosystem services.

Exploring the use of fish as indicators of eicosapentaenoic and docosahexaenoic supply in lake ecosystems.

An adequate supply of food sources with high levels (i.e., weight proportion of total fatty acids) and contents (i.e., absolute amount per mass) of long chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are important for ecosystems. Therefore, the supply of EPA and DHA from basal food sources is a useful indicator of ecosystem health. To determine whether EPA and DHA levels and contents in fish can be used as indicators of EPA and DHA supply in lakes, five dominant species of fish and basal food sources (seston and sediment) were collected monthly from June to November from 2016 to 2021 from Lake Hachiro, Japan. Seston and Hypomesus nipponensis were collected from 12 lakes (one collection per lake) with varying seston contents in EPA and DHA. The trends of EPA and DHA in all fish species were similar to those of the basal food sources. Correlation analysis showed that the EPA levels were strongly correlated between fish and seston; moreover, the correlation coefficient increased when a 1- or 2-month moving average was applied to the basal food sources, suggesting that fish represent a time-integrated supply of EPA and DHA. EPA levels of H. nipponensis had the highest correlation coefficients with seston among all fish species. EPA levels of H. nipponensis were significantly correlated with those of seston among lakes. The results of this study suggest that H. nipponensis is a useful indicator of EPA and DHA supplies in lake ecosystems.

Structural and functional changes in Artificial Reefs ecosystem stressed by trophic modelling approach: Case study in the Bay of Biscay

Artificial Reefs (ARs) are commonly cited as a tool used for increasing fishery production and reinstating ecosystem functionalities. The assessment of ARs deployment is mostly based on analysis of the evolution of fish communities. Recently, studies have focused on trophic modelling to understand the functioning of such ecosystems in a more holistic approach. Trophic models are able to address this concern by describing the interaction between species at different trophic levels and based on the quantification of energy and matter flows through ecosystems. These models allow the application of numerical methods – also called Ecological Network Analysis (ENA) – to characterize emergent properties of the ecosystem. Usually, ENA indices are proposed as indicators of ecosystem health as they are sensitive to different impacts on marine ecosystems. In the present study, the Ecopath software is used to build an ecosystem model composed of 23 compartments, from detritus and phytoplankton to mammals, to describe the situation “before” and “after” the deployment of ARs in the south of the Bay of Biscay along the Landes coast. In addition, ENA indices are calculated for two periods, “before” and “after” the deployment of artificial reefs, to compare network functioning and the overall properties of the structural trophic network. Our results show little structural change in the ecosystem, with a rearrangement of the trophic levels and a simultaneous increase in biomass and system maturity. These preliminary results evidently need to be confronted with other environmental factors such as, for instance, substrate composition, proximity to natural reefs and larval supply. Nonetheless, we consider that the maturity index could be used as a new indicator to assess the evolution of ARs with specific management objectives.

Use of remote sensing-based pressure-state-response framework for the spatial ecosystem health assessment in Langfang, China.

Land use/land cover changes are occurring at an unprecedented rate and scale because of the economic development that has jeopardized the ecosystem's health. Ecosystem health should be studied and monitored at spatiotemporal scale to promote sustainable development and ecological civilization. The goal of this study was to assess the spatial ecosystem health of Langfang at the city and administrative levels using city's regional characteristics. Remote sensing-based pressure-state-response (PSR) framework, analytical hierarchy process (AHP), and principal component analysis (PCA) were utilized for spatial ecosystem health index (SEHI) formulation, indicator weighting, and indicator selection in several epochs (1990, 2003, 2013, and 2021), respectively. SEHI was formulated by combining subindices of pressure, state and response. The spatial ecosystem pressure index (SEIP) identified that the pressure was increasing on the ecosystem. In contrast, the spatial ecosystem state index (SEIS) pointed out an improvement in the state of the ecosystem since 1990. The worst state of the ecosystem was observed for the year 2013. The spatial ecosystem response index (SEIR) indicated that the response of the ecosystem towards the exerted pressures and states remained variable; however, it was reasonably good in 1990. All the administrative units of Langfang were associated with a healthy score for the spatial ecosystem health index (SEHI) for 1990 (pre-industrialization epoch), while the SEHI significantly reduced in 2013 (industrialization epoch) however improved for the later epochs (circular economy and ecological civilization epoch). The SEHI was moderately healthy for Dachang, Dacheng, Guan, Guangyang, and Yongqing while relatively healthy for the remaining administrative units in 2021. SEHI identified that spatial health has been improving since 2003 though not reaching the 1990's level for Langfang. Therefore, efforts should be focused on minimizing pressure and stabilizing the state to improve the spatial ecosystem health of Langfang. The developed SEHI can assist policymakers in analyzing regional health, identifying development strategies, driving environmental restoration, and quantifying needed changes.

Year-round weather alters nest-provisioning rates in a migratory owl.

As global temperatures and precipitation become more extreme, habitat specialists are at particular risk of being pushed past their environmental tolerance limits. Flammulated Owls (Psiloscops flammeolus) are small migratory owls that breed in temperate conifer forests of western North America. Their highly specialized nesting and foraging requirements make them indicators of ecosystem health. Using 17 years of nest observations, we investigated how annual weather patterns affected Flammulated Owl nesting and foraging behaviors during the breeding season. We used generalized linear models with a changepoint parameter to evaluate nest provisioning and nestling growth rates in years of extreme temperature and precipitation. We also evaluated how adult mass, division of labor, and productivity varied based on precipitation and temperature. Compared to wet and warm years, adults made more frequent prey deliveries to nestlings in dry and cold years, particularly early in the night and early in the season, and they experienced earlier changepoints in these years. We found a significant effect of temperature on the number of fledglings in broods, but weather did not affect other variables including productivity, nestling growth rates, adult masses, and division of labor. Our findings suggest that extreme annual weather patterns influence insect prey availability during the Flammulated Owl breeding season, forcing adults to work harder to provision for nests during dry and cold years. While productivity and nestling growth did not vary between years, these may incur a long-term tradeoff in adult survival.

Changes in Abundance and Distribution of the Sea Pen, Funiculina quadrangularis, in the Central Adriatic Sea (Mediterranean Basin) in Response to Variations in Trawling Intensity

Marine resources exploitation through bottom trawling affects marine ecosystems; thus, management should consider the presence of sensitive species as ecosystem health indicators. Epibenthic organisms such as sea pens are widely used to assess benthic conditions, as their populations are declining where trawling is intense. The Pomo/Jabuka Pits fishing ground in the Adriatic Sea, subject to various management measures over the years, is a nursery for European hake and hosts a small, but dense, population of Norway lobster and a remarkable abundance of pink shrimp. The sea pen Funiculina quadrangularis shares its habitat (sandy-muddy bottoms) with these crustaceans. Through UnderWater TeleVision surveys conducted from 2012 to 2019, F. quadrangularis abundance and distribution were quantified in relation to changes in the spatiotemporal distribution of fishing efforts. The average density (n/m2) of colonies was calculated for three periods: BEFORE implementation of measures (before 1 July 2015), during an INTERMEDIATE period in which limitations changed (2 July 2015 to 31 August 2017), and AFTER the implementation of a Fishery Restricted Area (from 1 September 2017). F. quadrangularis revealed an increase in density where fisheries were closed, even after a short period. This showed how management measures can positively influence epibenthic communities and that sea pens can be indicators of impact and/or recovery of habitats.

The role of diseases in unifying the health of global estuaries

Establishing a universal indicator of estuary health is an ongoing challenge for coastal ecology that is made more pressing due to the threat that climate change and anthropogenic activity pose to them. Historically, estuarine health was measured through basic physical, chemical, and biological traits, which have been used to routinely monitor estuaries for more than 30 years. However, it is unclear if they are dynamic enough to accurately assess ecosystem health changes driven by the pressures of climate change and anthropogenic activity. Measuring estuarine health indicators and noting incipient indicators relevant to the evolving threats of climate- and anthropogenic-related stressors on estuarine ecosystems is vital for safeguarding them into the future. Monitoring the presence and vitality of disease in estuarine ecosystems may prove to be a significant indicator of estuarine health. Here we review 22 years of literature (354 papers) to identify the role of marine diseases as critical indicators of long-term estuary health compared to traditional methods, with the goal of identifying a key indicator and underlying unifier of other health metrics. As indicators of both general ecosystem health and of multiple other stressors, diseases play a disproportionately significant role in estuary health in the face of climate- and anthropogenic-related stressors. Marine diseases are a unifier of structural and functional estuary health indicators and must be observed and modeled further.

Exploring invertebrate indicators of ecosystem health by focusing on the flow transitional zones in a large, shallow eutrophic lake

The river–lake transitional zone provides a unique environment for the biological community and can reduce pollution inputs in lake ecosystems from their catchments. To explore environmental conditions with high purification potential in Lake Taihu and indicator species, we examined the river-to-lake changes in water and sediment quality and benthic invertebrate communities in the transitional zone of four regions. The spatial variations in the environment and invertebrate community observed in this study followed the previously reported patterns in Taihu; the northern and western regions were characterized by higher nutrient concentrations in water, higher heavy metal concentrations in sediment, and higher total invertebrate density and biomass dominated by pollution-tolerant oligochaetes and chironomids. Although nutrient concentrations were low and transparency was high in the eastern region, the taxon richness was the lowest there, which disagreed with the previous findings and might be due to a poor cover of macrophytes in this study. The river-to-lake change was large in the southern region for water quality and the invertebrate community. Water circulation induced by strong wind-wave actions in the lake sites of the southern region is assumed to have promoted photosynthetic and nutrient uptake activities and favored invertebrates that require well-aerated conditions such as polychaetes and burrowing crustaceans. Invertebrates usually adapted to brackish and saline environments are suggested to be indicators of a well-circulated environment with active biogeochemical processes and a less eutrophic state in Taihu, and wind-wave actions are key to maintaining such a community and natural purifying processes.

Taxonomic and functional diversity of macroinvertebrates in sediment and macrophyte habitats: A case study, the Ibrahimia Canal, Nile River, Egypt

The taxonomic and functional diversities of macroinvertebrates are a critical indicator of ecosystem health. This study focuses on the taxonomic and functional diversities of the assemblage structure of macroinvertebrates in the Ibrahimia Canal, Egypt. They were compared across two different substrate habitats: sediment-associated and macrophytes-associated habitats. Significant variations in the taxonomic and biological trait community composition in the two substrate habitats were recorded, with high taxa abundance in sediment substrate and increased diversity in macrophyte substrate. In sediment substrates, burrow dweller and collector-filterer taxa were the main characteristics, while tube dweller and collector-gatherer were the main traits of macrophytes substrate. The taxonomic and functional indices tended to increase from sediment to macrophytes substrate; however, there was an increase in Rao’s quadratic entropy index (RaoQ) for sediment substrate habitat. Redundancy analyses explained the association between environmental factors and macroinvertebrate taxa and traits. Total suspended solids, dissolved oxygen, chemical demand oxygen, and phosphate were the key environmental drivers of the taxonomic and functional diversities of macroinvertebrates. Integration between the approaches to taxonomic and functional diversity is recommended to give insight into explaining and managing the freshwater ecosystem.

Northeast Pacific eelgrass fish communities characterized by environmental DNA represent local diversity and show habitat specificity

AbstractFish biodiversity is an important indicator of ecosystem health and a priority for the National Park Service in Drakes Estero, a shallow estuary within Point Reyes National Seashore, Marin County, California. However, fish diversity has yet to be described following the removal of oyster aquaculture infrastructure within Drakes Estero from 2016 to 2017. We used environmental DNA (eDNA) to characterize fish biodiversity within Drakes Estero. We amplified fish eDNA with MiFish primers and classified sequences with a 12S rRNA reference database. We identified 110 unique operational taxonomic units (OTUs, at 97% similarity) within the estuary from 40 samples across 4 sites. From these 110 OTUs, we identified 9 species and 13 taxonomic groups at the genus, family, order, or class level within the estuary. Species‐level assignments are limited by a lack of representative sequences targeted by the MiFish primers for 42% of eelgrass fishes in our region that we identified from a literature review in the Northeast Pacific (NEP) from Elkhorn Slough to Humboldt Bay. Despite this limitation, we identified some common Drakes Estero fishes with our eDNA surveys, including the three‐spined stickleback (Gasterosteus aculeatus), Pacific staghorn sculpin (Leptocottus armatus), surfperches (Embiotocidae), gobies (Gobiidae), and a hound shark (Triakidae). We also compared fish biodiversity within the estuary with that from nearby Limantour Beach, a coastal site. Limantour beach differed in community composition from Drakes Estero and was characterized by high relative abundances of anchovy (Engraulis sp.) and herring (Clupea sp.). Thus, we can distinguish estuarine and non‐estuarine sites (<10 km away) with eDNA surveys. Further, eDNA surveys accounted for greater fish diversity than seine surveys conducted at one site within the estuary. Environmental DNA surveys will likely be a useful tool to monitor fish biodiversity across eelgrass estuaries in the Northeast Pacific, especially as reference databases become better populated with regional species.

Influence of water quality on benthic macroinvertebrates in a groundwater-dependent wetland

Benthic invertebrates communities are frequently used as indicators of aquatic ecosystem health since many species are sensitive to pollution and abrupt changes in their environment. Limited knowledge exists on the interlinkages of hydrological dynamics, water quality and the ecological character of groundwater-dependant ecosystems especially in developing countries. In this study we assessed the sensitivity of benthic macroinvertebrates to water quality dynamics in the Barotse Floodplain, a groundwater-dependant wetland. Benthic invertebrates were sampled in the dry season using the kick-net method at selected points upstream, mid-stream and downstream. The selection of sampled points was based on an initially conducted water quality survey that characterized the wetland into mainly two water types, NaHCO3 (upstream) and CaMgHCO3 (downstream). Canonical Correspondence Analysis (CCA) was used to investigate the influence of water quality on macroinvertebrate subclass-taxa level. Furthermore, factor analysis was used to derive the processes propagating the observed water quality variability. It was established that the composition and diversity of macroinverbrate communities at subclass-taxa level was influenced by effects of the wetland flood pulse, salinity (mineralisation) from groundwater input and biogeochemical processes during the expansion and contraction of the floodplain-river exchange. This study has demonstrated that biomonitoring was effective in capturing the natural processes/regimes of the environmental (such as flooding) and thus has potential to be used for mointoring extreme effects of phenomenon such as climate change. It is recommended that, the families, genus and species taxonomic levels are needed to improve the understanding of responses of the subclass-taxa level and the detection of specific contamination signatures, to ensure wetland conservation and protection. Integrated water resources management for wetlands thus should incorporate biomonitoring conjuctively with traditional methods to ensure vital ecosystems are not compromised at the expense of maximizing the economic and social welfare of humanity.

The relationship between tree species and wood colonising fungi and fungal interactions influences wood degradation

Deadwood is one of the main terrestrial carbon (C) pools and its decomposition is fundamental in biogeochemical cycles. As fungi are the main wood degraders, a study was carried out on deadwood-colonising fungal community changes as a function of host plants and wood degradation. Deadwood fungal communities were investigated in adjacent woody plantations of hybrid poplar, willow and black locust established in the early 2000 s and abandoned for fifteen years. Lying deadwood was estimated in the three plantations and wood decay (WD) visually assessed using a 3-class scale. Fungal colonization of wood samples was assessed using culture-based methods and identified with morphological and molecular features. Wood colonising fungal communities differed in composition both between host plants and WD classes (P < 0.001). Ligninolytic white rot fungal species (Basidiomycota) prevailed in black locust and poplar, where they co-colonised all three wood decay classes in association with soft rot fungal agents. In willow, Daldinia chilidiae, a ligninolytic ascomycete, co-colonised deadwood with fungal species associated with tree dieback (Botryosphaeriaceae); whilst soft rot fungi principally colonised the highest wood degradation class. Results showed high fungal preference towards tree species that was most evident in ligninolytic fungi. Moreover, different wood decay paths were deduced from fungal changes across the three wood degrading classes and the necromass distribution in those classes. The co-habitation of white rot and soft rot fungi in all the wood decay classes of poplar and black locust indicated a continuum decay process; whilst the prevalence of soft rot fungi in the almost decomposed class in willow, suggested sequential succession of primary and secondary phases in deadwood degradation. Wood degradation is influenced by plant species and the native fungal microbiome and is mediated by multiple biotic interactions and environmental factors, which supports the use of wood colonising fungi as indicators of forest ecosystem health.

Paired environmental DNA and dive surveys provide distinct but complementary snapshots of marine biodiversity in a temperate fjord

AbstractMarine biodiversity is a key indicator of ecosystem health and can be assessed using a variety of methods, including environmental DNA (eDNA) sampling. However, the ecology of eDNA in physically dynamic nearshore environments remains uncertain, particularly with regards to how eDNA stratifies with depth. Here, we paired eDNA sampling with dive surveys at six sites in Knight Inlet, British Columbia, Canada. eDNA samples were collected from the surface, midwater column and bottom (8–25 m depth) at each site, while dive surveys focused on the bottom (benthic) habitat. Amplicon sequencing using the mitochondrial 12S rRNA gene (targeting fish) and the COI gene (targeting marine invertebrates and algae) resolved significant differences in community composition in surface waters compared with midwater and bottom. Differences by depth were greater than differences across sites, with surface waters dominated by salmon (Oncorhynchus spp.) and rotifer DNA, and midwater and bottom samples largely dominated by Pacific herring, copepods, and mussels. eDNA samples collected at the surface, therefore, may not accurately capture benthic communities, particularly in systems with high levels of freshwater input such as coastal temperate fjords. Over small spatial scales, particularly in systems with strong stratification, adding samples from different depths may be more effective at maximizing inferred diversity rather than sampling more sites. In general, there was low overlap in species detection between dive and eDNA surveys (less than 10% for each taxonomic group – fish, invertebrates, and algae). However, we observed clear strengths for each method – dive surveys provided better taxonomic resolution, while eDNA resolved greater total diversity. These results suggest that the two survey methods can be used in tandem to provide distinct and complementary snapshots of marine biodiversity in the nearshore environment.

Geospatial mapping of ecoraces of tasar silkworm (Antheraea mylitta Drury) using remote sensing and geographic information system techniques

Tropical Tasar silkworm Antheraea mylitta Drury (Family: Saturniidae) produces Tasar silk which has very high demand globally and because of their wide range of distribution in tropical regions, they have adapted to different niches forming different ecoraces. In Odisha, alone seven types of ecoraces of A. mylitta have been reported, namely Modal, Sukinda, Nalia, Jata-Daba, Adaba, Umerkote, and Boudh. These ecoraces show differences in their phenotypes, genetic constitution, fecundity, voltinism, etc. In the past few decades, there is the substantial deterioration of habitats due to many anthropogenic activities. This has resulted in a large decline in wild Tasar cocoon production. Lepidopterans are accepted as ecological indicators of ecosystem health and it is apprehended that through anthropogenic and climatic factors this precious genetic resource, which took millions of years to evolve, may face the threat of extinction shortly if adequate conservation measures are not taken. This paper attempts the geospatial mapping of these ecoraces in the state of Odisha through RS and GIS tools, which will provide a greater scenario for their conservation

The Everglades vulnerability analysis: Linking ecological models to support ecosystem restoration

Understanding of the Everglades’ ecological vulnerabilities and restoration needs has advanced over the past decade but has not been applied in an integrated manner. To address this need, we developed the Everglades Vulnerability Analysis (EVA), a decision support tool that uses modular Bayesian networks to predict the ecological outcomes of a subset of the ecosystem’s health indicators. This tool takes advantage of the extensive modeling work already done in the Everglades and synthesizes information across indicators of ecosystem health to forecast long-term, landscape-scale changes. In addition, the tool can predict indicator vulnerability through comparison to user-defined ideal system states that can vary in the level of certainty of outcomes. An integrated understanding of the Everglades system is essential for evaluation of trade-offs at local, regional, and system-wide scales. Through EVA, Everglades restoration decision makers can provide effective guidance during restoration planning and implementation processes to mitigate unintended consequences that could result in further damage to the Everglades system.

A Novel Vegetation Index Approach Using Sentinel-2 Data and Random Forest Algorithm for Estimating Forest Stock Volume in the Helan Mountains, Ningxia, China

Forest stock volume (FSV) is a major indicator of forest ecosystem health and it also plays an important part in understanding the worldwide carbon cycle. A precise comprehension of the distribution patterns and variations of FSV is crucial in the assessment of the sequestration potential of forest carbon and optimization of the management programs of the forest carbon sink. In this study, a novel vegetation index based on Sentinel-2 data for modeling FSV with the random forest (RF) algorithm in Helan Mountains, China has been developed. Among all the other variables and with a correlation coefficient of r = 0.778, the novel vegetation index (NDVIRE) developed based on the red-edge bands of the Sentinel-2 data was the most significant. Meanwhile, the model that combined bands and vegetation indices (bands + VIs-based model, BVBM) performed best in the training phase (R2 = 0.93, RMSE = 10.82 m3ha−1) and testing phase (R2 = 0.60, RMSE = 27.05 m3ha−1). Using the best training model, the FSV of the Helan Mountains was first mapped and an accuracy of 80.46% was obtained. The novel vegetation index developed based on the red-edge bands of the Sentinel-2 data and RF algorithm is thus the most effective method to assess the FSV. In addition, this method can provide a new method to estimate the FSV in other areas, especially in the management of forest carbon sequestration.

Effects of Natural Land Cover, Anthropogenic Disturbance, Space, and Climate on Oribatid Mite Communities in Canada’s Oil Sands Region

Soil contains a diverse fauna and microflora that are vital for maintaining healthy soils and their various ecosystem services. Oribatid mites are typically highly abundant arthropods in the soil and are used as indicators for environmental monitoring. The aim of this study was to determine oribatid mite community response to natural land cover, anthropogenic disturbance, space, and climate in the oil sands region of Alberta, Canada. Our results found that oribatid mite total abundance was significantly reduced by mining, cultivation, and well sites. Species richness was significantly reduced by mining and cultivation. Shannon’s diversity index was significantly higher for all natural land cover types, seismic lines, and forest harvest. Additionally, species diversity was lower under the relative influence of energy-related soft linear disturbances than for naturally vegetated sites and forest harvesting, and was lowered further by anthropogenic disturbances with more impact on soil integrity (cultivation, mines, urban/industrial, road/trail verges, well sites). Abundance, richness, and diversity also increased with increased frost free period and with eastward longitude. Mite community composition included a notable composition difference between lowland habitats and upland forest types, and between natural land cover and intense anthropogenic disturbance types (e.g., mines, cultivation). Our study highlighted oribatid mite communities’ response to natural land cover, anthropogenic disturbance and spatial–climatic factors assessed over broad spatial scales and the potential utility of oribatid mites as ecosystem health indicators under multiple ecological drivers.

A systems-level model of direct and indirect links between environmental health, socioeconomic factors, and human mortality

Major efforts are being made to better understand how human health and ecosystem health are influenced by climate and other environmental factors. However, studies that simultaneously address human and ecosystem health within a systems-level framework that accounts for both direct and indirect effects are rare. Using path analysis and a large database of environmental and socioeconomic variables, we create a systems-level model of direct and indirect effects on human and ecosystem health in counties throughout the conterminous United States. As indicators of human and ecosystem health, we use age-adjusted mortality rate and an index of biological integrity in streams and rivers, respectively. We show that: (i) geology and climate set boundary conditions for all other variables in the model; (ii) hydrology and land cover have predictable but distinct effects on human and ecosystem health; and (iii) forest cover is a key link between the environment and the socioeconomic variables that directly influence human health.

Earthworms shape prokaryotic communities and affect extracellular enzyme activities in agricultural soil

Earthworms are known for their important role in soil ecosystem functioning and are used as indicators of ecosystem health. Earthworms and soil microorganisms are major players in soil ecosystem processes. However, understanding of their interactions is limited. Using microcosms, we studied the effect of earthworms on soil microorganisms in entire soil mesocosms by comparing soil with and without earthworms. Soil microbial activity was determined by an extracellular enzyme activity assay, while soil DNA was used to determine prokaryote abundance by quantitative PCR targeting 16S rRNA genes and community composition and diversity by amplicon sequencing of 16S rRNA genes. The microbial activity showed an indication of increase of chitinase, α-glucosidase, β-glucosidase and endo-β-glucanase during incubation with a specific increase in endo-β-glucanase activity in the presence of earthworms. Importantly earthworms decreased species richness (p = 0.002) and were a significant factor (p = 0.008) in shaping soil prokaryotes community structure. Moreover, our results revealed enrichment of bacterial phyla of Bacteroidetes and Proteobacteria, as well as reduction in relative abundance of the archaeal phylum Thaumarchaeota, suggesting that the presence of earthworms favors specific microbes in soil. Further, differential abundance analysis showed strong correlations between enzymatic activities (all tested except phosphomonoesterase) and relative abundances of specific bacterial OTUs. Our findings suggest that earthworms influence the soil microbial communities and their activity in soil, and hence earthworm-prokaryote interactions should be incorporated in future soil microbiome studies.

Disturbance-Dependent Variation in Functional Redundancy Drives the Species Versus Functional Diversity Relationship across Spatial Scales and Vegetation Layers

Since species’ traits are closely linked to ecosystem functioning, the species versus functional diversity relationship (the SD–FD relationship) is considered a valuable indicator of ecosystem health. However, the extent to which the SD–FD relationship varies among disturbed versus undisturbed subtropical forests and whether the conclusion depends on the spatial scale of the observation or vegetation layer remains unclear. In this study, using plots of 100 m2, 400 m2 and 2000 m2, we gathered species and functional diversity data for woody and non-woody vegetation from replicate sites of undisturbed mature forests versus disturbed shrubland and plantations from subtropical China. Our analyses indicated that the species richness versus functional richness relationship, as well as the species evenness versus functional evenness relationship, varies markedly among disturbed versus undisturbed forests and woody versus non-woody layers. Scale-dependent variations in the SD–FD relationship were evident mainly in the woody layers or evenness component. Additional analyses revealed that disturbance-dependent variation in the community-level functional redundancy and species-level functional uniqueness can partly explain the observed variation in the SD–FD relationships. Overall, our study demonstrated that the SD–FD relationships are positive, but the relationship’s slope varies with contexts, partly due to variations in community-level functional redundancy and species-level functional uniqueness.