Revealing the impact of forest succession processes on changes in plant diversity is crucial for understanding the mechanisms that maintain plant diversity across various succession stages. While previous research has predominantly focused on the influence of environmental factors or management strategies on plant diversity within rubber plantation understories, there is a scarcity of studies examining the effects of forest succession processes on plant diversity. This study focuses on the plant diversity of the understory herbaceous layer within the rubber forest of the Yinggeling area, located in National Park of Hainan Tropical Rainforest. It employs a spatial analysis approach, rather than a temporal one, to examine the characteristics of the understory herbaceous community. The findings revealed that (1) The understory of Yinggeling rubber plantations harbors 175 plant species from 149 genera and 75 families, with Gramineae and Rubiaceae representing 46.45% of total species. And the dominant families are Rubiaceae, Gramineae, and Moraceae, with Ficus and Pteris being the dominant genera. (2) The dominant species vary with succession duration, with Tetrastigma pachyphyllum dominating in 0-year succession, Paspalum conjugatum in 3-year succession, and Microstegium fasciculatum in 7-year succession. (3) Diversity indices such as the Shannon–Wiener index, Simpson index, and Pielou index peak at 7 years of natural succession, while the species richness is highest at 3 years. (4) The similarity coefficient between understory herbaceous plant communities in rubber plantations undergoing 0 and 3 years of natural succession is highest 0.56, indicating a significant similarity, while similarity is lowest between 0 and 7 years of succession. This research shows that natural restoration helps increase species diversity in the understory herb layer of rubber forests. Succession leads to changes in the dominant families, genera, and species of the herbaceous layer. This change can be attributed to the intraspecific competition and ecological competition that occur during the succession process, leading to changes in biological and resource allocation.

The energy needs of the human population inevitably affect natural environments, but the effects on wildlife of human modifications of habitat specifically for geothermal projects are scarcely known. Through acoustic monitoring, we quantified at Proyecto Geotérmico Las Pailas II, Guanacaste, Costa Rica, the impact of forest openings on the diversity and community composition of aerial insectivorous bats. Our data revealed that artificial clearing causes a border effect, an environment where the diversity of species and activity levels of insectivorous bats increase with respect to other habitats analysed. We discuss that, due to the combination of environmental properties and resource availability variables of the border habitats, in addition to the acoustic abilities of the bat species detected, borders represent transitional spaces where species adapted to uncluttered and background-cluttered spaces can easily commute and forage. The artificial clearings created by the geothermal project had a positive effect on aerial insectivorous bat species; however, this pattern cannot be assumed for other organisms within the area. Therefore, we highlight the importance of quantifying the influence of energy-extracting projects on biodiversity metrics and the use of this information to make informed decisions regarding managing and conserving natural resources.

Although parasite community studies are growing in numbers, our understanding of which macro-ecological and evolutionary processes have shaped parasite communities is still based on a narrow range of host–parasite systems. The present study assessed the diversity and endoparasite species composition in New Zealand deep-sea fish (grenadiers, family Macrouridae), and tested the effects of host phylogeny and geography on the structure of endoparasite communities using a distance decay framework. We found that grenadiers from the Chatham Rise harboured a surprisingly high diversity of digeneans, cestodes and nematodes, with different species of grenadiers having different parasite assemblages. Our results demonstrate that community similarity based on the presence/absence of parasites was only affected by the phylogenetic relatedness among grenadier species. In contrast, both phylogenetic distance among grenadiers (measured as the number of base-pair differences of DNA sequences) and geographic distance between sample locations influenced the similarity of parasite communities based on the parasites' prevalence and mean abundance. Our key findings highlight the significant effect of deep-sea host phylogeny in shaping their parasite assemblages, a factor previously neglected in studies of parasite communities in deep-sea systems.

Dirivultid copepods (Siphonostomatoida), one of the most successful meiobenthic organisms found at deep-sea hydrothermal vents, have been the focus of most previous ecological studies among meiofauna in these habitats. The ecology of Harpacticoida, a major benthic copepod group in typical deep-sea floor, however, is not well understood in terms of variations in community structure and controlling factors at venting sites. The spatial heterogeneities in benthic harpacticoid composition and their association with environmental parameters were investigated at hydrothermal vent chimney structures in the calderas of three neighbouring sea knolls (Bayonnaise Knoll, Myojin Knoll and Myojin-sho Caldera) in the western North Pacific. While a previous study had reported the distribution of dirivultids was strongly associated with spatial differences in stable carbon isotopic signatures (δ13C) of organic matter in the detritus on active chimneys in the field, multivariate analyses detected no significant corelation between the parameter and harpacticoid composition in this study. Instead, high associations of the harpacticoid composition with differences in water depth and total organic carbon (TOC) concentration were detected. Ectinosomatidae dominated at vent sites with lower TOC values in the shallowest Bayonnaise Knoll, while they were less prevalent at deeper vent fields in the other knolls, where Miraciidae was the most abundant family. This study indicated the availability of vent chemoautotrophic carbon is not a primary factor controlling the composition of harpacticoids even in the habitats on the hydrothermal vents, but instead by the food amount, regardless of its resources (including marine snow from the sea surface), in the study area.

Projects that aim to control invasive species often assume that a reduction of the target species will increase native species abundance. However, reports of the responses of native species following exotic species control are relatively rare. We assessed the recovery of the native community in five tidal wetland locations in which we attempted to eradicate the invasive common reed [Phragmites australis (Cav.) Trin. ex Steud.]. We tested whether 3 yr of treatment were able to eradicate Phragmites and promote recovery of the native plant community. After 3 yr of treatment, Phragmites density declined sharply in all treated stands, though it was not eradicated in any of them. Native plant cover increased significantly in treated areas, and community composition, particularly in smaller stands, converged toward that of uninvaded habitat. Thus, even within the relatively short timescale of the treatments and monitoring, significant progress was made toward achieving the goals of controlling Phragmites infestations and promoting native biodiversity. There was a trend toward greater promise for success in smaller stands than larger stands, as has been observed in other studies. A greater emphasis on monitoring whole-community responses to exotic plant control, across a range of conditions, would enhance our ability to plan and design successful management strategies.

Forest fires pose an important threat to tropical rain-forest biodiversity. In the present study, we assessed ground layer (herb and shrub) communities in six differentially disturbed landscape plots in East Kalimantan, Indonesia, including primary and logged forest and once-, twice- and frequently-burnt forest. Overall, we recorded 175 species of herbs and shrubs; richness was highest in twice-burnt forest and lowest in logged forest. Vegetation and topographical variables including the percentage of the plot burnt and tree abundance were significant predictors of variation in composition. The main compositional gradient showed a clear distinction between subplots in unburnt versus burnt forest. A subset of subplots in burnt forest, however, clustered together with subplots from unburnt forest. These plots were located in a network of relatively unscathed forest along floodplains that persisted in the burnt-forest matrix. Small plant species associated with unburnt forest included several species of Dryopteridaceae, Marantaceae and Rubiaceae. Species associated with once- and twice-burnt forest included Mikania scandens (Compositae), Microlepia speluncae (Dennstaedtiaceae), Nephrolepis cf. biserrata (Nephrolepidaceae), Lygodium microphyllum (Schizaeaceae) and Hornstedtia cf. reticulata (Zingiberaceae). The frequently-burnt landscape plot was characterized by a high cover of the grass species Imperata cylindrica and the invasive exotic shrub Chromolaena odorata. Importantly, these species and other exotics had also invaded the once- and twice-burnt forest and represent a potential threat to forest recovery.

Despite alterations caused by anthropogenic activities in Singaporean coral reefs, the sponge communities are quite diverse and Xestospongia testudinaria is one of the most common sponge species. In the present study, we used 16S rRNA gene barcoded pyrosequencing to characterize and compare bacterial communities from different biotopes (sponge, seawater and sediment) and to identify dominant bacterial symbionts of X. testudinaria in a Singaporean coral reef ecosystem. Our results showed that biotope appears to affect the richness, composition and abundance of bacterial communities. Proteobacteria was the most abundant phylum in sediment and seawater whilst Chloroflexi was more abundant in X. testudinaria. Members of the order Caldilineales (fermentation of organic substrates), Chromatiales (purple sulphur bacteria), Rhodospirillales (purple non-sulphur bacteria) and Syntrophobacterales (sulphate-reducing bacteria) were relatively more abundant in X. testudinaria samples.

Macroalgal fouling communities are potentially useful as bioindicators in environmental monitoring as they are considered to be sensitive to changes in environmental conditions and the use of artificial substrata facilitates the implementation of standardized sampling strategies. The response of macroalgal fouling communities on buoys to changes in water quality was investigated with a view to the possible utilization of these assemblages in environmental monitoring programmes. Seven study sites were selected based on previously collected environmental data and Principal Components Analysis (PCA) was used to order sites according to beam attenuation coefficient (BAC) and concentration of dissolved nitrates and phosphates, relative to a minimally impacted reference site. At each site, all fouling macroalgae were collected from 10 buoys of standard shape and size, and were identified to the lowest possible taxonomic level. Species composition and species dominance were highly variable among impacted sites, indicating that qualitative aspects of community structure may not be useful as indicators of changes in water quality. However, higher levels of nutrient enrichment and turbidity were associated with lower macroalgal species richness, lower overall abundances, and decreased diversities, and therefore these quantitative aspects of community structure are potentially useful as indicators of environmental change. Intermediate levels of turbidity and nutrient enrichment were associated with lower evenness, but did not influence species richness, suggesting that macroalgal abundances respond to changes in environmental conditions before species replacement occurs.

The ability of arbuscular mycorrhizal fungi (AMF) to influence the performance of nonnative invasive plants in their introduced range has received increasing attention. The dependence of the invasive nonnative vine pale swallow-wort on AMF was studied in three greenhouse experiments. The aims of the present work were to (1) determine AMF colonization levels of field-collected pale swallow-wort plants and several co-occurring native and nonnative plant species, (2) evaluate the growth response of pale swallow-wort to different components of the soil microbial community from an infested site, and (3) determine the growth response of pale swallow-wort when grown with a nonlocal AMF species. AMF root colonization was greater in pale swallow-wort (85, 98, and 50% arbuscules, hyphae, and vesicles, respectively) than in leek (72, 80, and 25%), a species that has been frequently used as a predictor of AMF density in soil. Root colonization of pale swallow-wort in the field was also greater than root colonization of common milkweed, a native herbaceous species often co-occurring in the same habitats, as well as two other herbaceous species, Canada goldenrod and blueweed. Survival of pale swallow-wort plants was significantly greater in soil collected underneath dense monospecific stands of pale swallow-wort in a Henderson Harbor, NY, field site than in sterilized soil. After 12 wk, plants grown in sterilized soil had a 33% survival rate, whereas all plants grown in the unamended soil, with an intact microbial community, were alive. Moreover, plants grown in the unamended soil were 130% taller, had 50% more leaves, and had 83% greater total biomass compared with plants grown in sterile soil. Plants grown in soil containing a Glomus intraradices isolate collected in Troy, AL, were 50% shorter and had 15% lower total biomass than plants grown in the unamended New York field soil. These pale swallow-wort seedlings also had a high mycorrhizal dependency of 93%. Plants grown in a sterilized soil that was reamended with an AMF-free microbial wash had significantly lower belowground and total biomass than plants grown in the unamended soil with the resident AMF community. There was a trend of decreasing height and biomass for plants grown in sterile soil relative to the unamended controls treatment. Plants grown in sterilized soil had significantly (28%) greater total biomass than plants reamended with the AMF-free microbial wash. These findings suggest that AMF occurring in invaded habitats have beneficial effects on pale swallow-wort survival and growth.

Water hyacinth is among the most widespread invasive plants worldwide; however, its effects on waterbirds are largely undocumented. We monitored site use by waterbirds at Lake Chapala, the largest lake in Mexico and recently designated Ramsar site, to evaluate the potential influence of water hyacinth cover on species composition and aggregate measures of the waterbird community, including waterbird density, species richness, and Simpson's index of diversity. We examined the response of waterbirds to changes in percent water hyacinth cover at 22 independent sites around the lake during six study seasons from May 2006 to February 2008. We found little evidence to suggest that percent water hyacinth cover affected aggregate community measures; however, multivariate analysis of relative species composition suggested that water hyacinth cover corresponded with seasonal species composition (Canonical Correspondence r = 0.66, P = 0.007) when seasonal site cover averaged 17.7 ± 4.67% (winter 2007). Several migratory species were not observed during this season, which could suggest that some small-bodied migratory species avoided Lake Chapala during the winter of high water hyacinth cover. We suspect that observed changes in the waterbird community are in response to species-specific tolerances for water hyacinth and indirect abiotic and biotic effects of its presence (e.g., invertebrate and fish composition).

Japanese knotweed and congeners are invasive to North America and Europe and spread aggressively along rivers establishing dense monotypic stands, thereby reducing native riparian plant diversity, structure, and function. Noxious weed control programs attempt to eradicate the knotweed with repeated herbicide applications under the assumption that the system will recover to a native assemblage which will inhibit future invasions. However, eradication efficacy studies typically only measure the amount of knotweed reduced, not the reestablished species diversity or plant origins. For a community scale efficacy study, we measured vascular plant species diversity and cover in riparian areas along five rivers in Washington State, 3 to 6 years after Bohemian knotweed was initially treated with herbicide. Plant species composition was compared between riparian sites treated to remove knotweed and reference sites where knotweed was absent. Sites where knotweed had been removed had significantly more exotic species and vegetative cover than reference sites; however, native species richness and cover were greater in reference sites and areas with more overstory vegetation. The native plants observed were primarily shade tolerant and perennial, as opposed to many of the exotics, which were shade-intolerant annuals. In general, reestablishment of native and exotic vegetation was not related to pretreatment knotweed stem count, size of the invaded area, or timing of herbicide application. However, residual native tree cover was negatively correlated with initial knotweed stem count. Monitoring the success of restoration objectives (e.g., native plant reestablishment or increased species diversity) and characterizing associated habitat features following knotweed eradication will help in the development of site-specific protocols for successful plant community scale restoration.

The relative importance of different bottom-up-mediated effects in shaping insect communities in tropical secondary forests are poorly understood. Here, we explore the roles of vegetation structure, forest age, local topography (valley vs. hill top) and soil variables in predicting fruit-feeding butterfly and tree community composition, and tree community composition in predicting fruit-feeding butterfly community composition, in different-aged naturally regenerating and primary forests of Kibale National Park, Uganda. We also examine which variables are best predictors of fruit-feeding butterfly species richness or diversity. Butterflies (88 species) were sampled with a banana-baited trap and trees (98 taxa) with a 40 × 20-m sampling plot at 80 sampling sites. The environmental variables explained 31% of the variation in the tree community composition, the best predictors being local topography, forest age and cover of Acanthus pubescens (a shrub possibly arresting succession). The fruit-feeding butterfly community composition was better predicted by tree community composition (explaining 10% of the variation) rather than vegetation structure, local topography or soil factors. Environmental variables and tree species richness (or diversity) were poor predictors of butterfly species richness (or diversity). Our results emphasize the importance of tree community to recovery of herbivorous insect communities in tropical secondary forests.

Most evidence suggests anthropogenic edges negatively affect rain-forest bird communities but little has been done to test this in Australasia. In this study, avifaunal detection frequency, species richness and community composition were compared between the edge and interior and between flat and more complex-shaped edges of riparian rain-forest tracts in Tropical North Queensland. The detection frequency and richness of guilds based on diet, foraging strata and habitat specialism were also compared. This study detected 15.1% more birds at the rain-forest edge compared with the interior but no difference in species richness. Edge shape had no effect on detection frequency or richness. Many guilds (subcanopy, closed forest, frugivorous and insectivorous species) experienced increased detection frequency at the edge relative to the interior, but for some guilds this response was reduced (habitat generalists) or reversed (understorey and mixed-flock species) along complex edges. Overall community composition was affected by edge distance but not by edge shape. Edge habitat was shorter and had more open canopy than the interior, supporting habitat-based explanations for the observed avifaunal edge effects. These results suggest generally positive edge effects in Australian rain-forest bird communities, possibly reflecting local resource distributions or a disturbance-tolerant species pool.

The importance of deterministic and stochastic processes in structuring ecological communities is an enduring debate. Although this debate is nearly a century old, the extent to which communities are structured by species interactions or chance events is a central issue in ecology. We examined the assemblages of plants living inside 119 birds’ nest ferns (Asplenium goudeyi), which are endemic to Lord Howe Island. Specifically, we investigated whether patterns of species richness and community composition were influenced by fern size, fern isolation and plant dispersal abilities. Fern size and fern isolation significantly predicted plant community richness. At the community level, plant composition patterns did not deviate from randomized expectations. Individual species occurrences increased with increasing community richness, and no species exclusions were observed. Wind-dispersed taxa, which accounted for 29% of all species, were well represented in isolated ferns. Comparatively, poorer dispersers were confined to ferns nearest the forest at the base of the cliffs. We suggest that dispersal plays a key role in structuring plant communities living within birds’ nest ferns, and that species interactions are less important. Our study emphasizes the importance of epiphytes with a nest-like growth form as habitat for plants in a harsh environment.

The abundance and community composition of phytoplankton are influenced by a suite of interacting environmental factors. Hong Kong's marine environment features a hydrographic gradient from an estuarine zone in the west to a transition zone in the middle and an oceanic zone in the east. Size fractionation combined with high performance liquid chromatography (HPLC) pigment analyses were used to investigate the phytoplankton communities in different hydrographic zones during summer (July–August 2009) and winter (December 2009–January 2010). Clear temporal and spatial variations in environmental parameters occurred among hydrographic zones. Results of principal component analysis (PCA) revealed that the major deviating factors among hydrographic zones were turbidity and salinity in summer and nitrate and phosphate in winter. Phytoplankton abundance showed significant temporal variations, but no zonal variations. Phytoplankton communities in all hydrographic zones were dominated by cells >5 µm in both summer and winter. Chlorophyll a concentrations for most size fractions correlated significantly with temperature. The high concentration of fucoxanthin indicated that the phytoplankton community was dominated by diatoms in both summer and winter, while dinoflagellates, cryptophytes, cyanobacteria and other minor groups occurred sporadically in low abundance. The spatial pattern of phytoplankton in Hong Kong's coastal seas did not reflect the hydrographic zonation, but the phytoplankton in the semi-enclosed Tolo Harbour and Deep Bay were different from those in the other zones.

Cross-species infection among humans, chimpanzees (Pan troglodytes) and baboons (Papio spp.) is potentially a significant public health issue in Africa, and of concern in the conservation of P. troglodytes. However, to date, no statistical comparisons have been made between the prevalence, richness and composition of parasite communities in sympatric populations of baboons and P. troglodytes. We compared parasite communities in sympatric P. troglodytes and Papio papio living in a wilderness site, in the Republic of Senegal, West Africa. We asked whether, in the absence of humans, there are significant differences between these hosts in their interactions with gastrointestinal parasites. We tested whether host, location, or time of collection accounted for variation in prevalence, richness and community composition, and compared prevalence across six studies. We concluded that, despite being closely related, there are significant differences between these two hosts with respect to their parasite communities. At our study site, prevalence of Balantidium, Trichuris and Watsonius was higher in P. papio. Papio papio harboured more parasites per host, and we found evidence of a positive association between Trichuris and Balantidium in P. troglodytes but not P. papio.

The nematode communities of Antarctica are considered simple. The few species present are well adapted to the harsh conditions and often endemic to Antarctica. Knowledge of Antarctic terrestrial ecosystems is increasing rapidly, but nematode communities remain to be explored in large parts of Antarctica. In soil samples collected at Byers Peninsula (Antarctic Specially Protected Area No. 126), Livingston Island we recorded 37 nematode taxa but samples showed great variation in richness and abundance. Nematode richness decreased with increasing soil pH, whereas total abundances, and the abundance of several trophic groups, were greatest at intermediate pH (around 6.5–7). Moreover, the community composition was mainly related to pH and less so to soil moisture. Trophic group, and total nematode, rotifer and tardigrade, abundances were generally positively correlated. Byers Peninsula is thus, by maritime Antarctic standards, a nematode biodiversity hotspot, and the presence of several previously unrecorded genera indicates that nematode species richness in maritime Antarctica is probably underestimated. Our results indicate that abiotic factors influence nematode communities with little evidence for biotic interactions. The unexplained heterogeneity in community composition is probably related to variation in microclimate, vegetation, topography and unmeasured soil properties, but may also be contributed to by biological processes.

The north-eastern Aegean Sea (NEA) is a marine system of high hydrological complexity, principally induced by the inflow and subsequent advection of the low salinity (<30) Black Sea water (BSW). This water mass occupies the upper layer (~0–20 m) of the NEA and plays a key role in the determination of circulation patterns and the generation of various frontal and eddy structures. Here we are concerned with the examination of mesozooplankton assemblages in the NEA during the thermal stratification period (July 2004) in two discrete sampling layers: (a) Layer 1 (from the base of halocline to the surface: ~0–20 m) which is directly influenced by BSW; and (b) the deeper ~20–50 m layer (Layer 2). Our main objective was to assess the response of mesozooplankton to the BSW and the associated hydrological structures. In July 2004, the BSW was mainly restricted in the eastern part of the NEA where it was entrapped in a ~50-km wide anticyclonic gyre (Samothraki gyre). A marked spatial differentiation in mesozooplankton assemblage structure, significantly related to this hydrodynamic partitioning, was detected in Layer 1. Sampling sites under the direct influence of low salinity–high temperature gyre waters were characterized by a considerably higher mesozooplankton stock than the remaining area, mainly due to the outstanding numerical dominance of the cladoceran species Penilia avirostris. Copepods displayed notably low densities within the gyre and low species diversity, the calanoid Temora stylifera was the only abundant species. The mesozooplankton community outside the gyre zone shifted towards lower levels of total abundance, with a lesser contribution of cladocerans and an increase in the importance of small-sized copepods (e.g. Acartia clausi, Paracalanus parvus, copepodites of Oithona spp. and Clausocalanus spp.). In the subsurface layer (Layer 2), the mesozooplankton community also exhibited spatial heterogeneity which could be hardly explained by variability in environmental parameters. The periphery of the anticyclone below the halocline was distinguished from the remaining neritic area, presenting markedly high mesozooplankton productivity and distinct group composition. An inverse pattern in the mesozooplankton stock vertical distribution was observed at the periphery of the gyre (Layer 2> Layer 1) comparative to the remaining sites (Layer 1 > Layer 2), which was mainly due to unusually high concentrations of surface-living zooplankters below the halocline. The latter could be explained in terms of expected water flow patterns in an anticyclonic eddy.