Ecological Role Of Species Research Articles

Two near-chromosomal-level genomes of globally-distributed Macroascomycete based on single-molecule fluorescence and Hi-C methods

Discinaceae holds significant importance within the Pezizales, representing a prominent group of macroascomycetes distributed globally. However, there is a dearth of genomic studies focusing on this family, resulting in gaps in our understanding of its evolution, development, and ecology. Here we utilized state-of-the-art genome assembly methodologies, incorporating third-generation single-molecule fluorescence and Hi-C-assisted methods, to elucidate the genomic landscapes of Gyromitra esculenta and Paragyromitra xinjiangensis. The genome sizes of two species were determined to be 47.10 Mb and 48.20 Mb, with 23 and 22 scaffolds, respectively. 10,438 and 11,469 coding proteins were identified, with functional annotations encompassing over 96.47% and 94.40%, respectively. Assessment of completeness using BUSCO revealed that 98.71% and 98.89% of the conserved proteins were identified. The application of comparative genomic technology has helped in identifying traits associated with of heterothallic life cycle traits and elucidating unique patterns of chromosomal evolution. Additionally, we identified potential saprotrophic nutritional modes and systematic phylogenetic relationships between the two species. Therefore, this study provides crucial genomic insights into the evolution, nutritional type, and ecological roles of species within the Pezizales.

Change in cephalopod species composition in the overexploited coastal China seas with a closer look on Haizhou Bay, Yellow Sea

Climate change and intensive fishing have affected not only population abundance, but also species composition. Cephalopods have been increasing in abundance in the world ocean under climate change due to their flexible life-history traits, including the over-exploited China Seas. Despite the increasing importance of coastal cephalopods in the China Seas, there have been no reports of changes in either species composition, nor the ecological roles of species with different life-history traits. Thus, this study first presents the changes in species composition of coastal cephalopods throughout the China Seas as summarized from fishery-independent survey reports over the last six decades. This is followed by an investigation of species composition of cephalopods in Haizhou Bay in the Yellow Sea. The ecological roles of two currently targeted cephalopods, Amphioctopus fangsiao and Loliolus spp. (Loliolus beka and Loliolus japonicus), are evaluated using an ecosystem model. The species composition of coastal cephalopods in the China Seas has changed since the 1960s, from species of large size and high value to small-size, low-value species. Cephalopod species composition in Haizhou Bay shows great seasonality, which is probably due largely to the characteristics of their life cycle. The population abundance of A. fangsiao and Loliolus spp. appear to be affected by ambient water temperature, and population distribution of Loliolus spp. seems to correlate with water depth. Occupying the highest trophic level in this ecosystem, A. fangsiao potentially displays strong top-down control over other organisms. Loliolus spp. are keystone species showing higher keystoneness in the autumn, owing to a low abundance of fish species which normally prey on them. The species-specific life-history traits and ecological roles of cephalopods are therefore important factors to consider in order to manage them effectively.

Quantification of the Indirect Use Value of Functional Group Diversity Based on the Ecological Role of Species in the Ecosystem

An important issue in biodiversity valuation is gaining a better understanding of how biodiversity conservation affects economic activities and human welfare. Quantifying the economic benefits of biodiversity for human well-being is not straightforward. Here, we expand the ecosystem service cascade by (i) attributing a methodology to the different steps of the cascade to assess the effects of changes in functional group diversity on economic activities; (ii) including multiple attributes for defining functional diversity and (iii) integrating a dynamic ecological model simulating complex interactions and feedbacks between species with an economic model assessing the effects of changes in functional group diversity for gross revenues. The stepwise methodological framework integrates a production function approach with a market price-based approach in order to investigate the indirect use value of functional group diversity based on the ecological role of species in the ecosystem. The methodology is applied to estimate the relationship between the gross economic value of Chinook salmon (Pacific Northwest, United States) and the diversity of freshwater macroinvertebrates. The results of our analysis emphasize the importance of biological diversity for sustaining ecosystem goods and services. The analysis provides a tractable framework for quantitatively exploring the economic consequences of changes in functional group diversity.

Ecological Impacts of Oil-Palm Plantation on Butterfly and Bird Species Diversity

The expansion of oil-palm plantations in Indonesia is often blamed as the driving causes of deforestation and impacts on environmental changes including the destructed biodiversity. Our understanding regarding environmental impacts on biodiversity is still limited. We address this issue by examining the diversity of butterfly and bird species under two type habitat conditions in Central Borneo. We calculated the butterfly and bird species number, richness, evenness, similarity, and composition inside the established oil-plantation area comprising four large-scale plantations and seven smallholding plantations, as habitat after plantation establishment. In comparison, we did so similarly inside secondary forest and shrubs, as habitat before oil-palm plantation establishment. Our results revealed that the habitat after plantation establishment exhibited a higher number of butterfly and bird species than the habitat beforehand. However, the richness, evenness, and similarity indices for the species revealed variations, which were affected by dominant species in two habitats. The establishment of oil-palm plantation brought about significant impacts on the composition of species and affected the species similarities between two habitats. The oil-palm plantation landscape and reserved forest vegetation were essential in supporting diversity and ecological role of species on habitat condition after oil-palm plantation establishment.

Diet of bottlenose dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from stomach content and stable isotope analyses.

The ecological role of species can vary among populations depending on local and regional differences in diet. This is particularly true for top predators such as the bottlenose dolphin (Tursiops truncatus), which exhibits a highly varied diet throughout its distribution range. Local dietary assessments are therefore critical to fully understand the role of this species within marine ecosystems, as well as its interaction with important ecosystem services such as fisheries. Here, we combined stomach content analyses (SCA) and stable isotope analyses (SIA) to describe bottlenose dolphins diet in the Gulf of Cadiz (North Atlantic Ocean). Prey items identified using SCA included European conger (Conger conger) and European hake (Merluccius merluccius) as the most important ingested prey. However, mass-balance isotopic mixing model (MixSIAR), using δ13C and δ15N, indicated that the assimilated diet consisted mainly on Sparidae species (e.g. seabream, Diplodus annularis and D. bellottii, rubberlip grunt, Plectorhinchus mediterraneus, and common pandora, Pagellus erythrinus) and a mixture of other species including European hake, mackerels (Scomber colias, S. japonicus and S. scombrus), European conger, red bandfish (Cepola macrophthalma) and European pilchard (Sardina pilchardus). These contrasting results highlight differences in the temporal and taxonomic resolution of each approach, but also point to potential differences between ingested (SCA) and assimilated (SIA) diets. Both approaches provide different insights, e.g. determination of consumed fish biomass for the management of fish stocks (SCA) or identification of important assimilated prey species to the consumer (SIA).

Trophic relationships in apex predators in an estuary system: A multiple-method approximation

The trophic level and ecological role of species in the ecosystem are determined by their feeding habits. While the trophic level and niche width are characteristic at population level, trophic overlap indicates the interaction between populations of a community. Three apex predators coexist in Uruguayan waters: Franciscana dolphin (Pontoporia blainvillei), South American sea lion (SASL, Otaria flavescens) and South American fur seal (SAFS, Arctocephalus australis). The two otariids consume different main prey species and have different isotopic niche, whereas feeding habits of Franciscana dolphin in Uruguayan waters remain practically unknown. This study aimed to determine Franciscana diet composition by stomach content and stable isotope (δ13C and δ15N) analyses, and to assess trophic overlap in diet composition as well as in isotopic niche space among the three apex predators. Diet composition of each species was estimated by Bayesian mixing models with prior information on the diet of predators. Moreover, Bayesian ellipses were used to define the isotopic niche space and overlap among the three species. Diets among predators varied: diet of SAFS was composed mainly by a few pelagic prey species, diet of SASL was more diverse and included pelagic and benthic preys, and for Franciscana dolphin the diet was mainly composed by coastal prey species. The SAFS had the largest isotopic niche area compared to the Franciscana and the SASL. The isotopic niche of the SASL did not overlap with those of the other two species. Although the Franciscana and the SAFS overlap in isotopic space, they do not overlap in feeding areas; this is because particulate organic matter δ13C values increase from inner Rio de la Plata to the estuary and the Atlantic Coast. Here, the relevance of using different sources of information to reach strong conclusions about feeding habits of marine predators and about co-use of resources is shown, mainly in environments where variation in δ13C can be related to diverse reasons.

Decadal changes in a NW Mediterranean Sea food web in relation to fishing exploitation

We analysed changes in the ecological roles of species, trophic structure and ecosystem functioning using four standardized mass-balance models of the South Catalan Sea (North-western Mediterranean). Models represented the ecosystem during the late 1970s, mid 1990s, early 2000s, and a simulated no-fishing scenario. The underlying hypothesis was that ecosystem models should quantitatively capture the increasing exploitation in the ecosystem from the 1970s to 2000s, as well as differences between the exploited and non-exploited scenarios. Biomass showed a general decrease, while there was an increase in biomass at lower trophic levels (TL) from the 1970s to 2000s. The efficiency of energy transfer (TE) from lower to higher TLs significantly increased with time. The ecosystem during the 1990s showed higher biomass and flows than during the 1970s and 2000s due to an increase in small pelagic fish biomass (especially sardines). Exploited food webs also showed similarities in terms of general structure and functioning due to high intensity of fishing already in the 1970s. This intensity was highlighted with low trophic levels in the catch, high consumption of production by fisheries, medium to high primary production required to sustain the catches and high losses in secondary production due to fishing. Significant differences on ecosystem structure and functioning were highlighted between the exploited and no-fishing scenarios. Biomass of higher TLs increased under the no-fishing scenario and the mean trophic level of the community and the fish/invertebrate biomass ratios were substantially lower in exploited food webs. The efficiency of energy transfer (TE) from lower to higher TLs was lower under the no-fishing scenario, and it showed a continuous decrease with increasing TL. Marine mammals, large hake, anglerfish and large pelagic fish were identified as keystone species of the ecosystem when there was no fishing, while their ecological importance notably decreased under the exploited periods. On the contrary, the importance of small-sized organisms such as benthic invertebrates and small pelagic fish was higher in exploited food webs.

A comparison of pitfall trapping and quadrat sampling of Carabidae (Coleoptera) on river banks

A comparison was made betweeen the "open" pitfall trap method and quadrat sample method in microhabitats on river banks. The latter method was found to give reliable estimates of the absolute abundance of carabid beetle species. In pitfall traps individuals of the carabid beetle Bembidion schuppelii were over-represented in a sub-optimal microhabitat compared with in optimal ones. The niche-overlap between this species and B. bipunctatum was 0.19 in quadrat samples and 0.59 in pitfall traps. There was no correlation between the relative abundance of individuals of species in quadrat samples and in pitfall traps. Individuals of larger carabid species were highly over-represented compared to smaller ones in pitfall traps, an effect that was independent of diurnal rhythm and life cycle category. Biomass of larger carabid species was also overestimated in pitfall traps compared to that of smaller ones. Imagines were more efficiently captured in pitfall traps than larvae. Pitfall traps had a higher number of species than quadrat samples in all investigated sites. In four of five cases the Shannon-Wiener index gave higher species diversity in pitfall traps than in quadrat samples. It is concluded that the "open" pitfall trap method is inappropriate to study dominance ratio, the ecological role of species and perhaps the species diversity within communities. The general insight into the community structure of carabid beetles may therefore be very biased.