Non-metric Multidimensional Scaling Ordination Research Articles

Distribution, Diversity, and Soil Associations of Wine Grape Plant-Parasitic Nematodes in Georgia, U.S.A., Vineyards.

Wine grape (Vitis vinifera and V. vinifera hybrids) production in Georgia occurs in three distinct regions (North, West, and South) which can be characterized by sandy, sandy-loam, or sandy clay-loam soils. We studied plant-parasitic nematode (PPN) communities in 15 wine grape vineyards from the three primary growing regions to understand which nematodes are a concern and what soil characteristics are associated with their occurrence and relative abundance. Twelve genera of PPNs were detected throughout the state: Belonolaimus, Helicotylenchus, Hemicycliophora, Heterodera, Hoplolaimus, Meloidogyne, Mesocriconema, Paratrichodorus, Paratylenchus, Pratylenchus, Tylenchorhynchus, and Xiphinema. Nonmetric multidimensional scaling ordination and multirank permutation procedure identified PPN community differences and soil characteristics that were associated by region. Indicator species analysis identified Helicotylenchus, Mesocriconema, Tylenchorhynchus, and Xiphinema as statistically associated with the West while Meloidogyne and Paratrichodorus were associated with the South. Our analyses further suggested that soil texture (percent sand, percent clay, and percent silt) and the lime buffer capacity at equilibrium (LBCEQ) were associated with PPN community structure while pH was not. When focused on a single vineyard in the North, multiple logistic regression analysis suggested a statistically significant association between Meloidogyne spp. and soil characteristics, including percentages of sand, pH, and LBCEQ. Our study supports the association between soil characteristics and specific nematode genera, as well as the emergence of LBCEQ, the soil measurement with the strongest statistical association with nematode community structure and Meloidogyne presence.

Piriformospora indica alter root-associated microbiome structure to enhance Artemisia annua L. tolerance to arsenic

Microorganisms in the rhizosphere are crucial allies for plant stress tolerance. Recent research suggests that by interacting with the rhizosphere microbiome, microorganisms can aid in the revegetation of soils contaminated with heavy metal(loid)s (HMs). However, it is unknown that how Piriformospora indica influences the rhizosphere microbiome to mitigate arsenic-toxicity in arsenic-enriched environments. Artemisia annua plants were grown in the presence or absence of P. indica and spiked with low (50) and high (150 µmol/L) concentrations of arsenic (As). After inoculation with P. indica, fresh weight increased by 37.7% and 10% in control and high concentration treated plants, respectively. Transmission electron microscopy showed that cellular organelles were severely damaged by As and even disappeared under high concentration. Furthermore, As was mostly accumulated by 5.9 and 18.1 mg/kg dry weight in the roots of inoculated plants treated with low and high concentrations of As, respectively. Additionally, 16 S and ITS rRNA gene sequencing were applied to analyze the rhizosphere microbial community structure of A. annua under different treatments. A significant difference was observed in microbial community structure under different treatments as revealed by non-metric multidimensional scaling ordination. The bacterial and fungal richness and diversity in the rhizosphere of inoculated plants were actively balanced and regulated by P. indica co-cultivation. Lysobacter and Steroidobacter were found to be the As-resistant bacterial genera. We conclude that P. indica inoculation could alter rhizosphere microecology, thereby mitigating As-toxicity without harming the environment.

Secondary succession of an unmanaged coppice woodland adjacent to late-successional, lucidophyllous forest in western Japan

ABSTRACT The combined effects of management history and ecosystem connectivity make it difficult to predict future dynamics of abandoned and unmanaged ecosystems. In Japan, unmanaged, secondary forests (satoyama) face risk of arrested or diverted succession, due to extensive human influence across the landscape. Proximity to climax forests, which function as seed sources, could determine the course of succession of abandoned satoyama. Here, we investigated spatial/temporal variation of species composition and stand structure of abandoned satoyama adjacent to a mature lucidophyllous forest in warm-temperate Japan to elucidate the course of succession after abandonment. Two study plots were established in the unmanaged, secondary forest at varying distances from the mature lucidophyllous forest. We calculated vegetation similarity indices among the plots to elucidate spatial variation and temporal change of species composition and stand structure and visualized relationships using nMDS (non-metric multidimensional scaling) ordination. Over the past 15 years, species composition and stand structure of the secondary forest have changed following the normal course of succession. This was because shade-intolerant shrubs, such as Rhododendron, were replaced by recruitment of climax species originating from the lucidophyllous forest. However, Quercus serrata (deciduous oak) and shade-intolerant evergreen trees continued to dominate the upper-canopy. Although the adjacent lucidophyllous forest is an effective seed source for recruitment of climax species, it may take several more decades for the secondary forest to reach late-successional composition and structure, due to legacy effects of past management.

Patterns and drivers of soil surface-dwelling Oribatida diversity along an altitudinal gradient on the Changbai Mountain, China.

Distribution patterns of biodiversity and environmental interactions are dominant themes in ecology. In montane ecosystems, biodiversity is closely associated with altitudinal gradients. However, studies of biodiversity in montane ecosystems are focused on plants and vertebrates, with relatively less on invertebrates. Here, the present study used a Vortis arthropod suction sampler to explore the biodiversity patterns of soil surface-dwelling Oribatida and their drivers along an altitudinal gradient (600, 800, 1600, 2000, and 2300 m) from typical temperate forests, evergreen coniferous forests, subalpine birch forests to alpine tundra on the north slope of Changbai Mountain, Northeast China. Trichoribates berlesei, Platynothrus peltifer, and Oribatula tibialis were the dominant soil surface-dwelling species on Changbai Mountain. Generally, alpha diversity and beta diversity of soil surface-dwelling Oribatida decreased with the rising altitude, with a peaking density value at 2000 m. The result of beta diversity showed that the structures of community were more influenced by the species turnover component than the nestedness component. Nonmetric multidimensional scaling (NMDS) ordination showed that the community structure of soil surface-dwelling Oribatida varied significantly along the altitudinal gradient. The variance partitioning showed that the elevation and climatic conditions determined the soil surface-dwelling Oribatida community. Spatial filtering represented by geographic and elevation distances was particularly associated with soil surface-dwelling Oribatida community variation between altitudes on Changbai Mountain. However, the variation of the Oribatida community between adjacent altitudes was only associated with geographic distance. Our study provides supportive evidence for the biodiversity analyzing of soil surface-dwelling Oribatida in montane ecosystems along an altitudinal gradient.

A metabarcoding protocol targeting two DNA regions to analyze root-associated fungal communities in ferns and lycophytes.

Detailed studies of the fungi associated with lycophytes and ferns provide crucial insights into the early evolution of land plants. However, most investigations to date have assessed fern-fungus interactions based only on visual root inspection. In the present research, we establish and evaluate a metabarcoding protocol to analyze the fungal communities associated with fern and lycophyte roots. We used two primer pairs focused on the ITS rRNA region to screen the general fungal communities, and the 18S rRNA to target Glomeromycota fungi (i.e., arbuscular mycorrhizal fungi). To test these approaches, we collected and processed roots from 12 phylogenetically distant fern and lycophyte species. We found marked compositional differences between the ITS and 18S data sets. While the ITS data set demonstrated the dominance of orders Glomerales (phylum Glomeromycota), Pleosporales, and Helotiales (both in phylum Ascomycota), the 18S data set revealed the greatest diversity of Glomeromycota. Non-metric multidimensional scaling (NMDS) ordination suggested an important geographical effect in sample similarities. The ITS-based approach is a reliable and effective method to analyze the fungal communities associated with fern and lycophyte roots. The 18S approach is more appropriate for studies focused on the detailed screening of arbuscular mycorrhizal fungi.

Responses of understory vascular plant communities up to 6 years after retention harvesting in planted Abies sachalinensis forests

Planted forests managed to supply timber are usually harvested by clearcutting but are also expected to contribute to biodiversity conservation. The retention forestry approach that retains important forest structures, such as trees and decayed logs at harvest, can be applied in planted forests to mitigate the negative impacts of clearcutting. Planted forests are disturbed by harvesting and postharvest silvicultural management activities, such as site preparation, planting, and weeding. The responses of understory vascular plant communities to various retention harvesting and postharvest silvicultural management were studied by comparing the composition of understory plant species before and after harvesting at the Retention Experiment for plantation FoREstry in Sorachi, Hokkaido, Japan (REFRESH). Dispersed and aggregated retention sites were established in planted Abies sachalinensis forests. In the dispersed retention sites, broad-leaved trees established in conifer plantations were retained. Clearcut and unharvested stands were used as controls and patch-cutting sites (one third of the area was clearcut by patches of 1-ha) were also established. Harvesting took place the year after the preharvest survey, and postharvest surveys were conducted in the first, third, and sixth years thereafter. The effects on species richness, the persistence of species occurrence in the preharvest survey, and the species composition of understory plants were then examined. Colonization by early seral species resulted in changes to the understory plant communities after harvesting and site preparation, irrespective of overstory tree retention. The species composition within aggregated retention patches was not altered, even though most overstory trees were blown down and are expected to provide a refuge for forest species. The presence of retained trees and steep slopes enhanced preharvest species persistence, which was presumed to be due to hampered soil disturbance. Harvesting and site preparation methods that avoid soil disturbance may help to maintain habitats for more understory plants in planted forests. The effects of weeding on the persistence of understory species differed from that of harvesting and site preparation. The trajectories for each site in the Non-metric multidimensional scaling ordination space were almost parallel from the preharvest to postharvest surveys, suggesting that the preharvest vegetation left a legacy. The direction of movement was reversed in the survey six years after harvesting. It is necessary to determine the resistance and resilience of understory plants within the management cycle (planting through harvesting) to establish management practices that maintain the diversity of understory plants in planted forests.

The synecology of endemic relict species Ramonda serbica (Gesneriaceae)

The article presents the results of a study of the plant communities of Ramonda serbica, primarily intended to increase knowledge of their species and syntaxonomic diversity. The dataset included 204 vegetation plots (relevés) of the two Balkan Ramondas (R. serbica and R. nathaliae), 174 digitised from published literature sources and 30 new ones from field sampling of R. serbica in Montenegro and North Macedonia. Nineteen associations and subassociations of R. serbica were identified, using hierarchical cluster analysis (the Sørensen index as a distance measure and the Flexible Beta method, ß −0.25). Three associations (Micromerio julianae-Ramondetum serbicae, Hylocomio splendentis-Ramondetum serbicae, Neckero pumillae-Ramondetum serbicae), three subassociations (Micromerio julianae-Ramondetum serbicae subass. allosoretosum persicae, Ceterachi officinarum-Ramondetum serbicae subass. festucetosum dalmaticae and subass. hylotelephietosum maximi) and one alliance Exsertotheco crispae-Ramondion serbicae are described as new. Both hierarchical cluster analysis and non-metric multidimensional scaling ordination support the distinction of 3 chorological/ecological groups of R. serbica communities: Adriatic-Ionian (xerophilous), Moesian (xero and mesophilous communities) and Illyrian-Scardo-Pindic (hygromesophilous). Communities of the Adriatic-Ionian cluster belongs to alliances Edraianthion, Centaureo cuspidatae-Portenschagillion ramosissimae and Campanulion versicoloris, of the Moesian one to Edraiantho graminifolii-Erysimion comati, and the Illyrian-Scardo-Pindic one to novel alliance Exsertotheco crispae-Ramondion serbicae.

Diet Patterns and Niche Overlap of Muskellunge and Co‐Occurring Piscivores in Minnesota Lakes

AbstractMuskellunge Esox masquinongy, Northern Pike E. lucius, Walleye Sander vitreus, and Largemouth Bass Micropterus salmoides are popular sport fish that often co‐occur in aquatic systems. Although numerous studies have investigated interactions among these species, the simultaneous evaluation of diet patterns and niche overlap among all four species has not been conducted. Our experimental design aimed to quantify diet overlap among Muskellunge and the other piscivores, while lakes without Muskellunge were also sampled to compare the diets of the other piscivores in their presence or absence. Diets of piscivores from 10 Minnesota lakes were collected via gastric lavage and quantified using an index of relative importance. Diets of individual species were compared among seasons and predator length categories, and among‐species comparisons were also conducted by season and relative to Muskellunge presence using permutational multivariate ANOVA (PERMANOVA). Muskellunge consumed a wide range of prey, whereas Northern Pike and Walleye diets consisted primarily of Yellow Perch Perca flavescens and centrarchids. Largemouth Bass consumed more invertebrates, especially crayfish Faxonius spp. No species exhibited seasonal diet shifts, but diets were different among length categories for all species except Walleye. Although nonmetric multidimensional scaling ordinations indicated shared prey use, PERMANOVA results indicated that the diets of Muskellunge and Largemouth Bass were most different from each other and the other piscivores' diets across all seasons. Conversely, Northern Pike and Walleye diets were similar regardless of season or Muskellunge presence. Finally, lake‐scale habitat variables were correlated with piscivore diets, and Yellow Perch abundance was correlated with Walleye diets. Our results indicate that while Muskellunge, Northern Pike, Walleye, and Largemouth Bass can coexist in a variety of lakes, populations of important prey and habitat variables should be examined before management actions (e.g., stocking) are implemented to ensure adequate prey availability and to ensure that competition among these piscivores is not increased to the detriment of existing fisheries.

Developing a new testate amoeba hydrological transfer function for permafrost peatlands of NW Siberia

The vast areas of permafrost peatlands in the West Siberian Lowland (WSL) hold a significant amount of carbon currently at risk due to human-caused global warming. The rapid thawing of about 20–60% of the frozen soils of Western Siberia adds to the destruction of the region's signature palsa landscape and the development of thermokarst lakes or fens. Due to the complex interactions between climate and the ecosystem that shape its formation and degradation, permafrost reacts in different ways to environmental changes. Understanding recent changes in Western Siberia requires knowledge of previous environmental transitions, which needs to be enhanced further. This study, aimed to create a hydrological testate amoebae (TA) transfer function (TF) from the Khanymei area in the WSL to reconstruct past hydrological conditions in permafrost peatlands. In addition, this research intended to examine the influence of TA communities living in lichens (genus Cladonia) on the performance of TF by integrating these data with a calibration data set. In the summer of 2019, 76 modern samples of Sphagnum, Cladonia, and vascular plants from permafrost and non-permafrost sites were collected. Moreover, one peat core was extracted from the same area to reconstruct the depth to water table (DWT) quantitatively. The Shannon's diversity index, a quantitative measure of species richness, was calculated for each sample to estimate the TA species diversity in a community. Non-metric multidimensional scaling ordination was applied to the dataset to explore the similarities in TA communities between samples and determine whether the DWT controls the TA community structure. Results showed that the typical transition of TA species along the microtopographic (wet–dry) gradient is influenced by the presence of lichens on the surface of the peatland. Statistical analysis confirmed that TA communities in Cladonia are less affected by DWT. Therefore, the TF was constructed on the entire dataset (n = 75) and the dataset with Cladonia excluded (n = 55). Both these TFs showed satisfactory results. Even though the TF constructed on the entire dataset showed fewer predictive abilities, it provided a complete picture of the current vegetation conditions of Khanymei peatlands, where lichens are an essential element of the ecosystem. Therefore, it is assumed that TF with local environment traits may be more suitable for quantitative reconstruction, particularly in the newly explored permafrost area of Western Siberia.

22 Years of Aquatic Plant Spatiotemporal Dynamics in the Upper Mississippi River

Macrophyte (aquatic plant) recovery has occurred in rivers worldwide, but assemblage patterns and habitat requirements are generally not well understood. We examined patterns of species composition and macrophyte abundance in the Upper Mississippi River (UMR), spanning 22 years of monitoring and a period of vegetation recovery. Non-metric multidimensional scaling (NMDS) ordination revealed a gradient of macrophyte abundance and diversity for 25 species, which were associated with water velocity, depth, wind fetch, and water clarity. Three macrophyte genera of ecological and restoration interest (Zizania aquatica, Vallisneria americana, and Sagittaria spp.) occupied different ecological niches. Trends of NMDS values showed that Z. aquatica first co-occurred in shallow areas with Sagittaria spp. but then expanded into deeper, lotic habitats where V. americana often resided. Curve Fit regression analysis identified large areas of significant increases in the relative abundance of V. americana and percent cover of Z. aquatica in several reaches of the UMR from 1998–2019. Sagittaria spp. were more spatiotemporally dynamic, which may indicate specific habitat requirements and sensitivity to environmental gradients. Our analyses showed that these three ecologically important genera are spatiotemporally dynamic but have somewhat predictable habitat associations, which can guide macrophyte management and restoration in the UMR and other large, floodplain rivers.

Water or sediment? Assessing seasonal microplastic accumulation from wastewater treatment works

AbstractMicroplastics have become a major environmental concern around the world due to their potential impact on ecosystem functioning and biota. Microplastics enter freshwater systems through a variety of sources, with wastewater treatment work discharges being the most important source. The study aimed to determine the seasonal (i.e., hot–wet, cool–dry) variation in water and sediment microplastic abundances up- and down-stream of wastewater treatment works across two subtropical river systems (i.e., Crocodile and Luvuvhu) in South Africa. Overall, we found that microplastic type and distribution often did not show clear seasonal and site differences in water, hence microplastics were widespread across the studied systems and microplastic concentrations did not relate clearly to wastewater treatment works. This was further indicated by microplastic risk assessments which showed high pollution loads upstream. However, there were significant differences in sediment microplastic loads across seasons, indicating a source-sink effect towards the hot-wet season. The non-metric multidimensional scaling ordination based on microplastic densities for water and sediment discriminated slightly among systems, with major overlaps across the different locations and seasons. As a result, the current research indicates that seasonal context influences differences in microplastic concentrations, with the hot–wet season being associated with the high pollution loads, particularly within the sediments where this was more pronounced indicating the sink-source effect which is linked to sediments and not water.

Retained fish catches of artisanal fishers is dependent on fishing area, season and fishing gear type: A case study from the south coast of Kenya

The artisanal fishery is one of the sources of livelihood along the Kenya coast. Catches of retained fish of artisanal fishers between two fishing areas on the south coast of Kenya were compared. Artisanal fishers usually retain a portion of their daily catch which is reserved for family consumption while the rest is traded for cash to meet other family needs. This study hypothesized that retained fish catches were influenced by fishing area, fishing gear type and season. Daily fish landings and retained fish catches among artisanal fishers were monitored between August 2020 to July 2021 covering the South East Monsoon (SEM) and North East Monsoon (NEM) in Msambweni and Vanga fishing areas. A total of 60 fishers (30 for each area) were randomly selected and their retained catch monitored on a daily basis. The overall total fish landings were 23.3 tons and 210 tons in Msambweni and Vanga, respectively. The mean catch rate at Msambweni was 3.3 ± 0.12 kg.fisher-1day-1 in the NEM season and 2.2 ± 0.09 kg.fisher-1day-1 in the SEM season. Fish catch rates in Vanga was 8.5 ± 0.28 kg.fisher-1day-1 in the NEM season and 7.9 ± 0.29 kg.fisher-1day-1 in the SEM season. A total of 0.98 tons (only 4.2 %) of fish was retained versus 22.32 tons (95.8 %) not retained by the artisanal fishers in Msambweni, while in Vanga a total of 1.64 tons (only 0.78 %) was retained versus 208.36 tons (99.22 %) not retained. Retained fish catch varied significantly with season and type of fishing gear used (p < 0.05). Among the retained species in Msambweni, Siganus sutor made the highest contribution (53 %), followed by Lethrinus mahsena, (5.08 %). The species Euthynnus affinis and Sphyraena obtusata were mostly retained in Vanga with a contribution of 10.4 % and 10.2 %, respectively. The same retained fish species represented the most abundant species in the overall fish landings, however sizes were significantly smaller than those not retained by fishers (p < 0.05). Results of non-Metric Multidimensional Scaling (nMDS) ordination showed differences in species composition between fishing areas, seasons and fishing gear types with implication on fishers’ retained catches.

Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?

Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?

Insect Diversity in the Coastal Pinewood and Marsh at Schinias, Marathon, Greece: Impact of Management Decisions on a Degraded Biotope

The insects trapped in 63 plots positioned in a mixed pinewood and a marsh in Schinias, Marathon, Greece is studied relative to the anthropogenic disturbance. The last anthropogenic impact was recently intensified because of the Olympic Games in the area. One hundred and forty insect species were found that had abundances greater than two individuals in each sampling session in all plots. Seven insect community types were found using cluster analysis. The types, which corresponded to recognized habitats, re-emerged in a non-metric multidimensional scaling ordination. It was also found that insects tended to dwell in different plots, even in the same habitat. The invading P. halepensis Mill., which replaces P. pinea L., changed the entomofauna. The seven habitats had different numbers of bioindicators out of 74 insect species, not in general correlated with human impact. Three components of insect diversity were measured, and the temporal species turnover was consistently higher than the spatial one. In this sense, pine habitats were rated first in terms of overall insect diversity. In terms of biodiversity, the impact on the various biotopes was assessed utilizing the diversity–equitability index V, which indicated that the two P. halepensis-dominated habitats have negative V values together with the habitat dominated by Tamarix hampeana Nied. The conservation of P. pinea and the marsh habitats is recommended for conserving local entomofauna and stopping the progression of P. halepensis. The optimization of management strategies to meet the management goals of all elements of this degraded ecosystem seems to be crucial.

Observer error in grassland vegetation surveys: effects on species diversity metrics and species–abundance relationships

AbstractWe investigated the effect of observer error on four commonly used species diversity measures: species richness, Shannon–Weiner diversity, Shannon–Weiner evenness and Simpson’s index of diversity. We also evaluated how observer error affects inferences derived from multivariate analyses of species–abundance relationships as determined by non-metric multidimensional scaling (NMS) ordination. Grassland vegetation was sampled by three different botanists at two national park units in Missouri and Kansas, USA. The same plots were sampled by two of the botanists, who compiled lists of species composition and estimated foliar cover. Differences in the data records were then compared. Pseudoturnover (i.e. apparent turnover due to observer error) ranged from 17.1% to 22.1%, and differences in cover class estimation ranged from 21.5% to 30.5%. The percentage difference in species diversity measures between pairs of observers depended on how data were summarized, but were always <20%, and often <10%. Based on these results, species diversity metrics are affected to a relatively smaller extent by observer error than turnover indices. Turnover indices, however, contain more information because they track individual species, whereas species are interchangeable in most species diversity indices. Thus, less of the error is identified because of how species diversity indices are calculated. NMS ordinations revealed that while the characterizations of some plots by different observers were similar, differences between observers’ records for other plots resulted in greater separation in ordination space. Points representing one observer’s records were often shifted in ordination space in the same direction compared with the other observer.

Tree Species Composition and Diversity in Fire-Affected Areas of Miombo Woodlands, Central Mozambique

Fire strongly impacts the composition and structure of ecosystems, with consequences yet to be understood. We used Moderate Resolution Imaging Spectroradiometer (MODIS) data to map fire frequency and fire intensity and investigate their effects on miombo woodlands (MW) of central Mozambique. Tree species diversity was evaluated and compared using rarefaction curves. Non-metric multidimensional scaling (NMDS) ordination was used to identify patterns of species composition occurrence. The indicator value index method was applied to verify the occurrence of fire indicator species. In general, tree communities responded differently to varied fire regimes. We found low tree density in Intermediate fire frequency and intensity (IfIi) (180 trees ha−1) and High-frequency and Low intensity (HfLi) (316 trees ha−1) areas. The IfIi fire regime had the lowest carbon stocks (9.1 Mg ha−1), when compared to the rest of fire regimes. The species diversity decreased as fire intensity increased. IfIi areas had the maximum species diversity. The NMDS showed a varied species composition according to fire regime. We found a strong relationship between the species diversity and composition, and the pattern of fire occurrence in each fire regime. Our results are critical in supporting fire management policies and understanding fire regimes and their effects on miombo trees’ structure and composition.

Contextualizing patterns in short-term disaster recoveries from the 2015 Nepal earthquakes: household vulnerabilities, adaptive capacities, and change

Disaster recovery is multidimensional and requires theoretical and methodological approaches from the interdisciplinary social sciences to illustrate short- and long-term recovery dynamics that can guide more informed and equitable policy and interventions. The 2015 Nepal earthquakes have had catastrophic impacts on historically marginalized ethnic groups and Indigenous households in rural locations, arising in the immediate aftermath and unfolding for years afterward. Analyzing factors that shape household recovery patterns can help identify vulnerabilities and adaptive capacities in addition to signaling potential future changes. We pursue this goal using survey data from 400 randomly selected households in 4 communities over 2 10-week intervals at 9 months and 1.5 years after the earthquakes. Building on previous research that used non-metric multidimensional scaling ordination to identify patterns among multiple indicators of recovery (Spoon et al. 2020a), we investigate associations among these patterns of recovery, hazard exposure, and four domains of household adaptive capacity: institutional participation, livelihood diversity, connectivity, and social memory. Our results suggest: (1) social inequality, high hazard exposure, and disrupted place-based livelihoods (especially for herders, farmers, and forest harvesters on the geographic margins) had strong associations with negative recovery outcomes and displacement; (2) inaccessibility and marginality appeared to stimulate ingenuity despite challenging circumstances through mutual aid and local knowledge; (3) recoveries were non-linear, differing for households displaced from their primary home and agropastoral practice and those displaced to camps; and (4) some households experienced rapid changes while others stagnated. We contribute a temporal dataset with a random sample collected following a disaster that uses a theoretically informed quantitative methodology to explore linear and non-linear relationships among multidimensional recovery, adaptive capacity and change and provide an example of how vulnerabilities interact with adaptive capacity.

Tree species on environmental gradients in subtropical forest of northwest Belize, in the Maya Lowlands

We studied species composition and spatial distributions of tree species, and the underlying topography and soil, in subtropical forests of northwest Belize, a region in the Maya Lowlands. Our goal was to learn how much the spatial distributions of species vary and are predictable over the landscape. The study was done in old-growth, subtropical moist forest on limestone-derived topography and soil. We identified to species all trees ≥10 cm DBH in 209 400-m2 plots. For each plot, we characterized topographic setting and analyzed soil nutrients and texture. We recorded 3,984 individual trees of ∼140 tree species and used the 3,775 individuals of the 69 species occurring in ≥5 plots in multivariate analyses, including Nonmetric Multidimensional Scaling (NMS). NMS showed that 73% of the variation in species composition per plot was associated with the first three ordination axes. Sixteen out of the 34 quantitative variables we measured were correlated at R 2 > 10% with the axes. Of the categorical variables, Topographic Class was strongly associated with species composition, and USDA Texture Class less so. Of the 69 focal tree species, the abundances of 21 were correlated at R 2 > 10% with one or more axes of the NMS ordination. Importantly, these 21 species accounted for 68% of all individual trees sampled in the 209 plots. Twenty-three species were indicators of particular topographic and soil classes. We conclude that patterns of tree species distribution are strongly and predictably associated with different topographic and soil conditions in this landscape. In the past, the ancient Maya could have used this type of predictable plant–soil relationship to optimize their agriculture. In the future, our results are a basis for predicting local shifts in tree species distributions due to climate change.

Five Year Analyses of Vegetation Response to Restoration using Rock Detention Structures in Southeastern Arizona, United States

Rock detention structures (RDS) are used in restoration of riparian areas around the world. The purpose of this study was to analyze the effect of RDS installation on vegetation in terms of species abundance and composition. We present the results from 5 years of annual vegetation sampling which focused on short term non-woody vegetation response within the riparian channel at 3 restoration sites across southeastern Arizona. We examined the potential ways that RDS can preserve native species, encourage wetland species, and/or introduce nonnative species using a Control-Impact-Paired-Series study design. Species composition and frequency were measured within quadrats and zones on an annual basis. Multivariate bootstrap analyses were performed, including Bray-Curtis dissimilarity index and non-metric multidimensional scaling ordination. We found that response to RDS was variable and could be related to the level of degradation or proximity to groundwater. The non-degraded site did not show a response to RDS and the severely degraded site showed a slight increase in vegetation frequency, but the moderately degraded site experienced a significant increase. At the moderately degraded site, located between two historic ciénegas (desert wetlands), species composition shifted and nonnative species invaded, dominating the vegetation increase at this location. At the severely degraded site, pre-existing wetland species frequency increased in response to the installation of RDS. These findings extend the understanding of RDS effects on vegetation, provide scenarios to help land and water resource managers understand potential outcomes, and can assist in optimizing success for restoration projects.

Soil faunal communities in mass outbreak areas of the great web-spinning sawfly Acantholyda posticalis (Mats.) are impoverished compared to pest-free Scots pine forests

Mass outbreaks of pests defoliating Scots pine monocultures are of constant concern to foresters, and the increase in their frequency under conditions of a warming climate is expected. Repeated mass outbreaks usually involve the same areas, which suggests that predispositions to pest attack are shaped by certain stand characteristics or their habitat conditions. The aim of the study was to examine whether the soil invertebrate communities of pine forests with A. posticalis mass outbreaks differ from those of stands with no mass occurrence of this pest, despite analogous stand-habitat conditions and close proximity. Pine monocultures in two regions of Poland differing in the timing of the pest's mass occurrence were selected for the study. The soils of the studied monocultures, both in outbreak areas and reference tree stands, were characterized by strong acidity and low nutrient status. A lower (soil invertebrate communities) and a higher (Collembola communities) taxonomic resolution were used to assess the differences between the soil fauna of infected and reference stands. We show that soil invertebrate communities of the mass outbreak areas were characterized by impoverishment compared to those of reference forests. However, both invertebrate and Collembola communities, which in outbreak areas consisted of fewer taxa, did not differ significantly in density from reference tree stands. Nonmetric multidimensional scaling (NMDS) ordination of the collembolan communities revealed that not only their composition but also their structure in the mass outbreak areas differed significantly from those of uninfected tree stands. Further research is needed to clarify whether the depletion of soil invertebrates is a result of foliar insect feeding, or is rather a manifestation of weakened stands increasing their predisposition to attacks by pest insects.