Loss Of Species Diversity Research Articles

Impacts of elevated pCO2 on estuarine phytoplankton biomass and community structure in two biogeochemically distinct systems in Louisiana, USA

Ocean acidification has the potential to impact the ocean's biogeochemical cycles and food web dynamics, with phytoplankton in the distinctive position to profoundly influence both, as individual phytoplankton species play unique roles in energy flow and element cycling. Previous studies have focused on short-term exposure of monocultures to low pH, but do not reflect the competitive dynamics within natural phytoplankton communities. This study explores the use of experimental microcosms to expose phytoplankton assemblages to elevated pCO2 for an extended period of time. Phytoplankton communities were collected from two biogeochemically distinct Louisiana estuaries, Caillou Lake (CL) and Barataria Bay (BB), and cultured in lab for 16 weeks while bubbling CO2 enriched air corresponding to current (400 ppm) and future (1000 ppm) pCO2 levels. Results suggest that elevated pCO2 does not implicitly catalyze an increase in phytoplankton biomass (chlorophyll a). While pigment data showcased a parabolic trend and microscopic observations revealed a loss in species diversity within each major taxonomic class. By the end of the 16-week incubation, 10 out of the 12 cultures had a community structure analogous to that of the startup phytoplankton assemblage collected from the field. Natural phytoplankton assemblages exposed to elevated pCO2 experienced multiple transitional states over the course of a 16-week incubation, indicating that there is no deterministic successional pathway dictated by coastal acidification but community adaptation was observed.

Loss of only the smallest patches will reduce species diversity in most discrete habitat networks.

Under many global-change scenarios, small habitat patches are the most vulnerable to destruction. For example, smaller ponds are at greater risk in a drying climate and their loss would remove any obligate aquatic individuals present. We asked what proportional loss of species diversity from metacommunities comprised of discrete habitat patches should be expected from attrition (complete loss) of only the smallest patches under such a premise. We analyzed 175 published datasets for different taxonomic groups (vertebrates, invertebrates, and plants) and habitat types (islands, habitat islands, and fragments). We simulated the destruction of only the smallest patches to an approximate 20% of total area (range: 15.2%-24.2%) and analyzed species loss. Mean [±95% CI] species loss was 12.7% [10.8, 14.6], although 18.3% of datasets lost no species. Four broad patterns of species loss were evident, reflecting underlying differences in minimum area requirements and the degree of species turnover among patches. Regression modeling showed species loss increased with greater species turnover among patches (βSIM ) and decreased with greater area scaling of diversity (i.e., larger power-law island species-area relationship exponents). Losses also increased with greater numbers of single-patch endemics and with increasing proportions of patches destroyed. After accounting for these predictors, neither taxonomic group nor habitat type increased explained variation in species loss. Attrition of the smallest patches removed species in >80% of metacommunities, despite all larger patches and >75% of total area remaining intact. At both 10% and 20% area reduction, median species loss across all datasets was around 50% higher than predicted from methods based on the species-area relationship. We conclude that any mechanism of global change that selectively destroys small habitat patches will lead to imminent extinctions in most discrete metacommunities.

How does landscape anthropization affect the myrmecofauna of urban forest fragments?

We evaluate whether landscape variables surrounding urban remnant forest fragments influence ant diversity and its components in urban areas. The study was conducted in six riparian forest fragments in midwestern Minas Gerais State, Brazil, by sampling epigaeic and arboreal ants. Arboreal ants respond to fragmente isolation with changes in alpha, beta and gamma diversities. Isolation likely hinders dispersion and re-colonization such that the more isolated a fragment is, the less likely that new species arrive there. On other hand, epigaeic diversity did not show any response to variables of the surroundings or fragments, probably because natural periodic floods constitute a more severe disturbance for these ants. In addition, throughout the process of urbanization, anthropogenic improvements, such as paving, that prevent the natural percolation of water, increase the flooding of riparian soil. Arboreal ant species composition responds to percentage of urban area, fragment area and distance from the urban center, while epigaeic ants respond only to fragment area and percentage of urban area. We believe that even with the loss of species diversity and anthropogenic influences on fragments within urban centers, these areas are still important for species conservation. We also suggest the development of environmental protection projects for riparian áreas within urban centers, including investments in ecological corridors connecting fragments and public policies seeking to preserve these areas.

Ecological enhancement techniques to improve habitat heterogeneity on coastal defence structures

Sea level rise and higher storm frequency are increasing the need for the placement of hard coastal defences worldwide. The majority of these defences lack optimal habitats for intertidal species, resulting in low diversity and abundance. The construction of coastal defences within marine protected areas (MPA) is also increasing and this study investigates ways to limit the loss of species diversity and intertidal habitat caused by installing rock armour defence structures and other coastal developments. Arrays of holes and grooves were created on granite rock armour in the north of England at Runswick Bay, N. Yorkshire and limestone rock groynes in southern England at Boscombe, Poole Bay, Dorset. Runswick Bay is a Marine Conservation Zone (MCZ) designated for its intertidal habitat and Boscombe is located in close proximity to a Special Area of Conservation (SAC). After 12 months, the treatments had attracted new species to the defence structures and increased the overall diversity and abundance of organisms compared to control areas. Mobile fauna including crabs and fish were also recorded utilising the holes and grooves at Boscombe. Non-native species were recorded in grooves at one site however their abundance was not significantly different to that of control areas. At the southern site, species known to be spreading in response to climate change were found in treatments but not in control areas. The cost of the installation of these enhancement techniques was low in relation to that of the defence scheme and could be easily incorporated before, during or after construction. Through evaluation of the use of these ecological enhancement techniques on coastal structures, it is suggested that they have considerable potential to increase biodiversity on artificial structures, particularly when used within large-scale coastal engineering defence projects.

Ranked Tree Shapes, Nonrandom Extinctions, and the Loss of Phylogenetic Diversity.

Phylogenetic diversity (PD) is a measure of the evolutionary legacy of a group of species, which can be used to define conservation priorities. It has been shown that an important loss of species diversity can sometimes lead to a much less important loss of PD, depending on the topology of the species tree and on the distribution of its branch lengths. However, the rate of decrease of PD strongly depends on the relative depths of the nodes in the tree and on the order in which species become extinct. We introduce a new, sampling-consistent, three-parameter model generating random trees with covarying topology, clades relative depths, and clades relative extinction risks. This model can be seen as an extension to Aldous' one parameter splitting model ($\beta$, which controls for tree balance) with two additional parameters: a new parameter $\alpha$ quantifying the relation between age and richness of subclades, and a parameter $\eta$ quantifying the relation between relative abundance and richness of subclades, taken herein as a proxy for overall extinction risk. We show on simulated phylogenies that loss of PD depends on the combined effect of all three parameters, $\beta$, $\alpha,$ and $\eta$. In particular, PD may decrease as fast as species diversity when high extinction risks are clustered within small, old clades, corresponding to a parameter range that we term the "danger zone" ($\beta<-1$ or $\alpha<0$; $\eta>1$). Besides, when high extinction risks are clustered within large clades, the loss of PD can be higher in trees that are more balanced ($\beta>0$), in contrast to the predictions of earlier studies based on simpler models. We propose a Monte-Carlo algorithm, tested on simulated data, to infer all three parameters. Applying it to a real data set comprising 120 bird clades (class Aves) with known range sizes, we show that parameter estimates precisely fall close to the danger zone: the combination of their ranking tree shape and nonrandom extinctions risks makes them prone to a sudden collapse of PD.

P074 MICROBIAL COMPOSITION IS EFFECTIVELY IMPROVED BY COMBINATION THERAPY WITH FECAL MICROBIAL TRANSPLANTATION AND MULTIPLE ANTIBIOTICS FOR ULCERATIVE COLITIS

Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridium difficile infection. To provide effective FMT protocol for ulcerative colitis (UC) has been desired. We previously reported that the combination therapy with multiple antibiotic therapy (AFM: amoxicillin, fosfomycin and metronidazole) and FMT (Antibiotic FMT: A-FMT) synergistically contributes to the recovery of the phylum Bacteroidetes composition, which is associated with high clinical response for UC. Here, we constructed further additional microbial analyses at the species level to confirm whether Bacteroidetes species from donors actually colonized and contribute to its effective transplantation. AFM therapy was administered to patients for 2 weeks until 2 days before FMT. Donor fecal samples were collected on the day of administration and transferred via colonoscopy within 6 h. Microbiome analysis at the species level was performed by a method based on hsp60 sequences using Miseq. We found that dysbiosis in UC was involved the loss of species diversity among Bacteroidetes, resulting in hyper- and hypoproliferation of particular species. (Simpson’s diversity index; UC vs healthy donors, n = 27, 25; p = .0001). Moreover, in responders treated by A-FMT, the diversity significantly recovered up at 4weeks after FMT (baseline vs after A-FMT; n = 14, 14; p < 0.05) via transplantation of Bacteroidetes cells as supported by the high similarities of bacterial compositions among patients and their donors, in contrast, in the patients treated with FMT monotherapy and AFM monotherapy, there were no cases that exhibited the high similarities with their donors. This combination therapy alleviated intestinal dysbiosis, including loss of species diversity in UC. Eradiation of dysbiotic indigenous species by AFM pretreatment may promote the entry of living cells, improving the bacterial composition of the intestinal microbiota in UC.

P863 Eradication of dysbiotic indigenous species by multiple antibiotic pre-treatment contribute to effective faecal microbiota transplantation

Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridium difficile infection. To provide effective FMT protocol for ulcerative colitis (UC) has been desired. We previously reported that the combination therapy with multiple antibiotic therapy (AFM: amoxicillin, fosfomycin and metronidazole) and FMT (Antibiotic FMT: A-FMT) synergistically contributes to the recovery of the phylum Bacteroidetes composition, which is associated with high clinical response for UC. Here, we constructed further additional microbial analyses at the species level to confirm whether Bacteroidetes species from donors actually colonised and contribute to its effective transplantation. AFM therapy was administered to patients for 2 weeks until 2 days before FMT. Donor fecal samples were collected on the day of administration and transferred via colonoscopy within 6 h. Microbial analysis at the species level was performed by a method based on hsp60 sequences using next generation sequencing technique. We found that dysbiosis in UC was involved the loss of species diversity among Bacteroidetes, resulting in hyper- and hypoproliferation of particular species. (Simpson’s diversity index; UC vs. healthy donors; n = 27, 25; p = 0.0001). Moreover, in responders treated by A-FMT, the diversity significantly recovered up at 4 weeks after FMT (baseline vs. after A-FMT; n = 14, 14; p < 0.05) via transplantation of Bacteroidetes cells. In order to evaluate the influence of bacterial transplantation from donors to recipients, we calculated the similarities of species compositions among 86 samples from patients (A-FMT, AFM monotherapy, single FMT monotherapy; n = 17, 3, 3) at base line, patients after AFM, patients at 4 weeks post FMT and their donors. Among 14 clinical responders treated with A-FMT, species components in 9 responders at 4 weeks post A-FMT were most similar or second most similar to their individual donors, whose probability is 1/3655 or 1/1288. In contrast, in the clinical non-responders, patients treated with AFM monotherapy and patients treated with single FMT monotherapy, there were no cases that exhibited the most or second similarities with their individual donors. These results suggested that living cells of the Bacteroidetes were transplanted effectively from donor to recipient simultaneously with clinical improvement by A-FMT. This combination therapy alleviated intestinal dysbiosis, including loss of species diversity in UC. Eradication of dysbiotic indigenous species by AFM pre-treatment may promote the entry of living cells, improving the bacterial composition of the intestinal microbiota in UC.

P074 MICROBIAL COMPOSITION IS EFFECTIVELY IMPROVED BY COMBINATION THERAPY WITH FECAL MICROBIAL TRANSPLANTATION AND MULTIPLE ANTIBIOTICS FOR ULCERATIVE COLITIS

Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridium difficile infection. To provide effective FMT protocol for ulcerative colitis (UC) has been desired. We previously reported that the combination therapy with multiple antibiotic therapy (AFM: amoxicillin, fosfomycin and metronidazole) and FMT (Antibiotic FMT: A-FMT) synergistically contributes to the recovery of the phylum Bacteroidetes composition, which is associated with high clinical response for UC. Here, we constructed further additional microbial analyses at the species level to confirm whether Bacteroidetes species from donors actually colonized and contribute to its effective transplantation. AFM therapy was administered to patients for 2 weeks until 2 days before FMT. Donor fecal samples were collected on the day of administration and transferred via colonoscopy within 6 h. Microbiome analysis at the species level was performed by a method based on hsp60 sequences using Miseq. We found that dysbiosis in UC was involved the loss of species diversity among Bacteroidetes, resulting in hyper- and hypoproliferation of particular species. (Simpson’s diversity index; UC vs healthy donors, n = 27, 25; p = .0001). Moreover, in responders treated by A-FMT, the diversity significantly recovered up at 4weeks after FMT (baseline vs after A-FMT; n = 14, 14; p < 0.05) via transplantation of Bacteroidetes cells as supported by the high similarities of bacterial compositions among patients and their donors, in contrast, in the patients treated with FMT monotherapy and AFM monotherapy, there were no cases that exhibited the high similarities with their donors. This combination therapy alleviated intestinal dysbiosis, including loss of species diversity in UC. Eradiation of dysbiotic indigenous species by AFM pretreatment may promote the entry of living cells, improving the bacterial composition of the intestinal microbiota in UC.

An investigation of the soil seedbank and seed germination of perennial species in Belah (Casuarina pauper) woodlands in north-west Victoria

Semiarid and arid woodlands across much of southern Australia have been subject to prolonged high total grazing pressure leading to loss of species diversity and a lack of recruitment of long-lived perennial species. Regeneration of perennial species requires grazing pressure to be maintained at low levels, but gaps remain in our ecological understanding of regeneration potential. The present study investigated the abundance of germinable seed in the soil seedbank in high quality remnants of Casuarina pauper F.Muell. ex L.A.S.Johnson (Belah) woodlands in north-west Victoria. Seed viability and response to six seed pretreatments including dry heat, wet heat, smoky water, soaking in distilled water, cold stratification and sand scarification were also tested to determine whether seed factors may be limiting regeneration. Results suggest that seed viability was not a limiting regeneration factor for nine out of the 10 perennial species tested with the exception of Alectryon oleifolius S.T. Reynolds. Only small amounts of seed from perennial species, largely Chenopodiaceae species and C. pauper, were found in the soil seedbanks of intact sites, suggesting component perennial species do not maintain long-term soil seedbanks. Results suggest that natural recovery of perennial species diversity in depauperate sites will depend on seed dispersal.

Contrasting effects of functionally distinct tadpole species on nutrient cycling and litter breakdown in a tropical rainforest stream

Abstract There is growing interest in predicting how loss of species diversity and abundance affect the structure and functioning of ecosystems. Tadpole diversity and abundance can be exceptionally high in tropical streams, but, compared to other groups, relatively little is known about their functional roles. We assessed the trophic niches and investigated the contribution of tadpoles to nutrient recycling (excretion and egestion) and litter breakdown in streams. We used two ecomorphologically distinct tadpoles belonging to the two most dominant feeding guilds in Ranomafana, Madagascar: Boophis quasiboehmei (hereafter BQ, generalised mouthpart, grazer) and Mantidactylus melanopleura (hereafter MM, umbelliform funnel mouthpart, suspension feeder). We conducted field incubation experiments to quantify nutrients recycled from excretion and egestion, and set enclosures to analyse the effects of tadpoles on litter breakdown (leaves of Pauridiantha sp. and Chrysophyllum sp.) in nine treatments: control (no tadpoles), monospecific treatment (BQ or MM) at three densities (low, medium, high: 3, 6, 12 tadpoles/0.0625 m2, respectively) and mix‐species treatment (3 BQ + 3 MM, 6 BQ + 6 MM). BQ and MM occupied the same trophic level but tended to differ in their carbon isotopic signatures. MM excreted nitrogen (N) and phosphorus (P) at higher rates, but the two species had similar N:P molar excretion ratio. Nutrients recycled from faecal pellets (egestion) were not immediately available but needed to be mineralised: N increased with time in the water column and was more than 25 times higher in concentration at the end of the experiment (day 16), whereas P concentration showed a hump‐shaped pattern with a maximum value at day 4 of incubation. Effects of tadpoles on litter breakdown depended on tadpole identity, density and litter identity. Particularly, no breakdown occurred at low tadpole density, and effects were generally stronger on the softer texture leaves Pauridiantha sp. We found additive effects of tadpole diversity on litter breakdown. These findings indicate that (1) tadpoles with different mouthparts play different roles on the ecosystem; (2) tadpole faecal pellets are important latent sources of nutrients in freshwater environments; and (3) tadpole abundance exerted stronger effects than species diversity on litter breakdown, emphasising the importance of tadpole biomass and communities in tropical streams. Interspecific variation in nutrient recycling and differential effects on litter breakdown illustrate a strong linkage between species identity and ecosystem function.

Impacts of Nile Perch, Lates niloticus, introduction on the ecology, economy and conservation of Lake Victoria, East Africa

AbstractNile perch were secretly introduced into Lake Victoria in the 1950s, and officially in the 1960s, amid unresolved controversy. Proponents were of the view that the introduction would improve fisheries production and sport fishing. Although the former objective was achieved, the side effects were dire, including extinction of many native species, especially the ecologically important haplochromines, because of predation. The introduction also changed the habitat, trophic dynamics and water clarity. The change in water clarity is thought to be responsible for hybridization of haplochromines, further contributing to the loss of species diversity among cichlids. The establishment and expansion of the Nile perch also altered the fishery and socio‐economic settings characterizing the lake. A local economy which, until the early 1980s, was based on native fish species has been replaced by an export‐oriented exotic fish processing industry that destroyed the once‐cherished traditional resource. Other socio‐economic issues associated with Nile perch include the high HIV/AIDS prevalence among fishers, and border conflicts attributable to the migratory and transboundary nature of the fishery resource. Conservation measures for the fishery should include establishment of co‐management units that have so far registered both successes and challenges. Other efforts include establishment of the Nile perch Fisheries Management Plans that focus on curbing overfishing and eradicating illegal fishing.

Dimensions of biodiversity loss: Spatial mismatch in land-use impacts on species, functional and phylogenetic diversity of European bees.

AimAgricultural intensification and urbanization are important drivers of biodiversity change in Europe. Different aspects of bee community diversity vary in their sensitivity to these pressures, as well as independently influencing ecosystem service provision (pollination). To obtain a more comprehensive understanding of human impacts on bee diversity across Europe, we assess multiple, complementary indices of diversity.LocationOne Thousand four hundred and forty six sites across Europe.MethodsWe collated data on bee occurrence and abundance from the published literature and supplemented them with the PREDICTS database. Using Rao's Quadratic Entropy, we assessed how species, functional and phylogenetic diversity of 1,446 bee communities respond to land‐use characteristics including land‐use class, cropland intensity, human population density and distance to roads. We combined these models with statistically downscaled estimates of land use in 2005 to estimate and map—at a scale of approximately 1 km2—the losses in diversity relative to semi‐natural/natural baseline (the predicted diversity of an uninhabited grid square, consisting only of semi‐natural/natural vegetation).ResultsWe show that—relative to the predicted local diversity in uninhabited semi‐natural/natural habitat—half of all EU27 countries have lost over 10% of their average local species diversity and two‐thirds of countries have lost over 5% of their average local functional and phylogenetic diversity. All diversity measures were generally lower in pasture and higher‐intensity cropland than in semi‐natural/natural vegetation, but facets of diversity showed less consistent responses to human population density. These differences have led to marked spatial mismatches in losses: losses in phylogenetic diversity were in some areas almost 20 percentage points (pp.) more severe than losses in species diversity, but in other areas losses were almost 40 pp. less severe.Main conclusionsThese results highlight the importance of exploring multiple measures of diversity when prioritizing and evaluating conservation actions, as species‐diverse assemblages may be phylogenetically and functionally impoverished, potentially threatening pollination service provision.

Plant diversity, forest dependency, and alien plant invasions in tropical agricultural landscapes

Land-use change and intensification in tropical rainforest regions is generally linked to a loss in species diversity that especially affects forest-dependent species. Indonesia is currently the country with the highest deforestation rates worldwide with potentially devastating effects on its diverse and highly endemic flora and fauna. Here we present a comprehensive assessment of the varied effects of forest conversion and land-use intensification on vascular plant diversity across the four dominant land-use systems in the lowlands of Sumatra: rainforest, jungle rubber agroforest, rubber plantations, and oil palm plantations. We conducted plot-based species inventories in Jambi Province and assessed a total of 156,006 individuals and 1382 plant species. Forest had the highest levels of alpha, beta, and gamma diversity, followed by jungle rubber. Plant communities in oil palm plantations were characterized by a high density of herbaceous weeds, but low species numbers and low beta diversity. Species numbers were comparable in oil palm and rubber plantations, but the latter showed slightly higher beta diversity. Forest had a clearly distinct floristic composition while the floristic composition of the other systems - and especially the two plantation systems - converged. Alien species were almost completely absent from forest, but the number and relative abundance of alien species increased with increasing land-use intensity and was highest in oil palm plantations where 25% of the species and 62% of the individuals belonged to alien species. Our results represent a first quantitative baseline for how forest conversion in Southeast Asia causes loss in species richness, changes in floristic composition and vegetation structure, as well as a shift from native to alien-dominated plant communities.

Discovery of a new hypotrich ciliate from petroleum contaminated soil.

Pollution after oil spill represents extreme habitat for survival and is a major concern for loss of species diversity in the affected area. In this study, we investigated soil samples collected from a petrochemical industry, Ulsan, South Korea. The soil was in the phase of recovery from the contamination of crude oil spill. Detailed investigation, based on morphology, ontogenesis, and molecular phylogenetic methods, resulted in discovery of a novel hypotrich ciliate, i.e., Metasterkiella koreana n. gen., n. sp., which is morphologically characterized by a semirigid body, undulating membranes in Oxytricha pattern, 18 frontal-ventral-transverse cirri with cirrus V/3 placed posteriorly, one right and one left row of marginal cirri, four dorsal kineties, two dorsomarginal rows, and caudal cirri at the end of dorsal kineties 1, 2, and 4. Interestingly, during ontogenesis, formation of three common anlagen for the proter and the opisthe and involvement of cirrus V/3 in anlagen formation was observed. The dorsal ontogenesis was typical of oxytrichids, i.e., simple fragmentation of dorsal kinety 3 and formation of dorsomarginal rows close to the right marginal row. The new species was found to be similar with Sterkiella subtropica, except for some minor differences in morphometry, and at gene level with only one base pair difference. In phylogenetic analyses, based on SSU rRNA gene sequence, M. koreana cluster in a clade away from Sterkiella species, which could be explained by the differences in the morphogenetic pattern between these two genera. It is proposed that S. subtropica probably belongs to Metasterkiella; however, we do not perform changes and wait for the reinvestigation of its morphogenetic pattern.

English

The African elephant (Loxodonta africana Blumenbach) is a keystone species and ecosystem engineer. Elephants can cause serious damage to important trees, with only certain species being targeted such as Marula (Sclerocarya birrea A. Rich. Hoscht). High levels of elephant utilization may to some extent, compromise the viability of some woody plant populations leading to vegetation changes coupled with a possible loss of species diversity and/or structural diversity. In order to quantify their effect a study was initiated in 2014 to investigate their effect on tree height, degree of branch damage, the extent of debarking, and degree of stem damage. This was done within elephant&rsquo;s frequently and non&ndash;frequently used sites, and a neighbouring enclosure (control site). One hundred and fifty (50 per site) mature S. birrea trees were randomly selected within each site. Tree height was recorded using clinometers, degree of branch damage, extent of debarking (circumference debarked using different percentages of intensity) and degree of stem damage were assessed using different categories. Results indicated that the type elephant damage in both the frequently and non&ndash;frequently used sites was different, varied in intensity. A high proportion of Marula trees had been damaged. The size distributions of the trees showed that there was no regeneration. Furthermore, this study also demonstrated that elephants are able to damage Marula trees in several ways, the most destructive being bark stripping and pushing over trees. It is concluded that elephant impact is a powerful mechanism in shaping the structure and composition of Marula woodlands in the Atherstone Collaborative Nature Reserve. The findings of this study provide valuable baseline data and acts as a starting point for the introduction of adaptive management principles in small savanna reserves. This can be achieved by an intensive management programme responding to slight changes in the vegetation and would necessarily involve controlling elephant numbers. &nbsp; Key words: Crown diameter, damage, elephant, herbivory, marula.

Der Wald-Wild-Konflikt – was kann die Forstökonomie zur Lösung beitragen? (Essay)

The forest-game conflict – how can forest economics contribute to solve it? (Essay) Core parameters of forest economics such as land expectation value or highest revenue show that damage caused by wild ungulates can critically influence the economic success of forest enterprises. When assessing and evaluating the damage in order to calculate damage compensation, methods are applied in Germany that look either into the past (“cost value methods”) or into the future (“expected value methods”). The manifold uncertainties related to this evaluation over long-term production periods are taken into account within a framework of conventions through strongly simplifying assumptions. Only lately, the increased production risk due to game-induced loss of species diversity is also considered. Additional aspects that should be taken into account in the future are the loss of climate-adapted species, the change of the insurance values of forest ecosystems and the impossibility of specific management systems such as single-tree selection forestry due to the influence of game. Because of high transaction costs when assessing the damage, financial compensation should only be the “ultimate measure” and a meditation between stakeholder groups with the goal to find a cooperative solution before the damage occurs should be preferred.

Construction and optimization of ecological network for nature reserves in Fujian Province, China

The nature reserve is very important to biodiversity maintenance. However, due to the urbanization, the nature reserve has been fragmented with reduction in area, leading to the loss of species diversity. Establishing ecological network can effectively connect the fragmented habitats and plays an important role in species conversation. In this paper, based on deciding habitat patches and the landscape cost surface in ArcGIS, a minimum cumulative resistance model was used to simulate the potential ecological network of Fujian provincial nature reserves. The connectivity and importance of network were analyzed and evaluated based on comparison of connectivity indices (including the integral index of connectivity and probability of connectivity) and gravity model both before and after the potential ecological network construction. The optimum ecological network optimization measures were proposed. The result demonstrated that woodlands, grasslands and wetlands together made up the important part of the nature reserve ecological network. The habitats with large area had a higher degree of importance in the network. After constructing the network, the connectivity level was significantly improved. Although interaction strength between different patches va-ried greatly, the corridors between patches with large interaction were very important. The research could provide scientific reference and basis for nature protection and planning in Fujian Province.

Soil hydrology and vegetation as impacted by goat grazing in Vertisols and Regosols in semi-arid shrublands of northern Mexico

Shrubland ecosystems are less studied than grasslands regarding the role of domestic grazing on ecosystem degradation in the world, but particularly in Mexico. Of special concern is the paucity of research on soil hydrological responses to the impact of livestock. Here, we assessed the role that specific soil and surface characteristics play in soil hydrology as a response to goat grazing intensity in two different soil types, Regosol and Vertisol, in the Tamaulipan thornscrub of north-eastern Mexico. At each soil unit, a set of grazing regimes was identified, including heavy grazing (HG), moderate grazing (MG) and a no-grazing (NG) reference area, and selected soil properties and plant cover were evaluated. In Regosol sites, soil organic matter varied among all grazing regimes (4.6% higher on NG and 2.1% higher on MG with respect HG) and no dissimilarities on bulk density were recorded. For Vertisol sites, soil bulk density increased with grazing intensity (16% higher on MG and 37% higher on HG with respect to NG) whereas plant cover linearly decreased from 86% in NG to 29% in MG and 9% in HG sites. Soil organic matter content for Regosol, and plant cover and soil bulk density for Vertisol appeared as the best indicators of water infiltration and moisture retention for the grazing conditions assessed. Differences in those key driving variables may help explain surface hydrology responses to goat grazing in rangeland soils of Tamaulipan thornscrub ecosystems and possibly on similar rangelands around the world. Clear signs of vegetation degradation were also observed, manifested by a loss in species diversity and plant cover, especially under heavy grazing. This reflects unsustainable livestock management practices that should be avoided. This study contributes to improve our understanding of rangeland degradation processes and justifies devising more sustainable grazing management schemes.

Disturbance in the Mucosa-Associated Commensal Bacteria Is Associated with the Exacerbation of Chronic Colitis by Repeated Psychological Stress; Is That the New Target of Probiotics?

Psychological stress can exacerbate inflammatory bowel disease. However, the mechanisms underlying how psychological stress affects gut inflammation remain unclear. Here, we focused on the relationship between changes in the microbial community of mucosa-associated commensal bacteria (MACB) and mucosal immune responses induced by chronic psychological stress in a murine model of ulcerative colitis. Furthermore, we examined the effect of probiotic treatment on exacerbated colitis and MACB composition changes induced by chronic psychological stress. Repeated water avoidance stress (rWAS) in B6-Tcra-/- mice severely exacerbated colitis, which was evaluated by both colorectal tissue weight and histological score of colitis. rWAS treatment increased mRNA expression of UCN2 and IFN-γ in large intestinal lamina propria mononuclear cells (LI-LPMC). Interestingly, exacerbated colitis was associated with changes in the microbial community of MACB, specifically loss of bacterial species diversity and an increase in the component ratio of Clostridium, revealed by 16S rRNA gene amplicon analysis. Finally, the oral administration of a probiotic Lactobacillus strain was protective against the exacerbation of colitis and was associated with a change in the bacterial community of MACB in rWAS-exposed Tcra-/- mice. Taken together, these results suggested that loss of species diversity in MACB might play a key role in exacerbated colitis induced by chronic psychological stress. In addition, probiotic treatment may be used as a tool to preserve the diversity of bacterial species in MACB and alleviate gut inflammation induced by psychological stress.

Positive species diversity and above‐ground biomass relationships are ubiquitous across forest strata despite interference from overstorey trees

Summary There is growing concern over rates of global species diversity loss and its implications on healthy ecosystem functioning. While positive relationships between tree species diversity and forest biomass production have been observed, forests are structurally complex, consisting of understorey vegetation layers that also contribute to ecosystem functioning as they often account for the majority of species richness. However, relationships between understorey vegetation diversity and function are largely unexplored. Further, few studies have simultaneously assessed how both overstorey and understory vegetation interact and contribute to overall ecosystem function. By analysing Canada's National Forest Inventory data base using structural equation modelling, we explored the relationships between species richness and above‐ground biomass production across forest vegetation strata while accounting for potentially confounding factors, including climate, physical site characteristics and forest ageing. We found positive relationships between species richness and biomass production across all forest vegetation layers, but the relationship was strongest for the overstorey layer. Species richness of the understorey tree, shrub and herb layers was positively related to overstorey species richness. However, overstorey biomass had a negative effect on the biomass production of all understorey layers. Our results suggest that resource filtering by overstorey trees might have reduced the strength of the positive diversity–productivity relationships in the forest understorey, supporting previous hypotheses that the magnitude and direction of diversity–productivity relationships is context specific and dependent on the conditions of the surrounding environment. Further, heterogeneity in understory resources, as affected by the overstorey, may promote niche complementarity as the main mechanism driving diversity–productivity relationships in understorey vegetation.