Topic
Species richness
About: Species richness is a research topic. Over the lifetime, 61672 publications have been published within this topic receiving 2183796 citations.
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TL;DR: In this paper, the authors reviewed empirical findings on the species richness in urban parks across all species groups that have been studied and discussed the overall species richness of urban parks, its community attributes and drivers.
Abstract: There is growing recognition of urban areas as hosts for innovative ways to conserve and promote biodiversity. Parks, as one specific type of urban green space, constitute particularly important biodiversity hotspots in the cityscape. We reviewed empirical findings on the species richness in urban parks across all species groups that have been studied. The aim was to assess and discuss the overall species richness of urban parks, its community attributes and drivers. Search and subsequent selection process resulted in 62 papers from 25 different countries. For all examined species groups, the findings consistently show that parks are among the most species rich types of urban green spaces, but also that exotics constitute large shares, especially of plant species. Key ecological theories like the gradient approach and the island habitat ecological theory, and fundamental ecological relationships such as the species-area relationship are valid despite the manipulated ‘nature’ of parks and the surrounding urban matrix. Most studies surveyed large number of parks and applied ‘multi-scale’ approaches in tests of confounding variables, providing methodological strength. While matrix effects are consistently found to affect species richness negatively, the diversity of habitats and microhabitat heterogeneity contained in urban parks appears as the most decisive factor for the overall species richness. However, a constraint of research to date is the limitation of individual studies to one or a few species groups, rarely bridging between flora and fauna. Adopting ‘multi-species group’ approaches in future research is needed to further advance the understanding of the overall biodiversity of urban parks, and its drivers.
344 citations
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University of Tartu1, American Museum of Natural History2, Cheikh Anta Diop University3, Humboldt State University4, University of Copenhagen5, University of California, Davis6, University of Tokyo7, National University of Cordoba8, University of Minnesota9, University of Tennessee10, Duke University11, University of Florida12
TL;DR: A global analysis to disentangle the global determinants of diversity and community composition for ectomycorrhizal fungi-microbial symbionts that play key roles in plant nutrition in most temperate and many tropical forest ecosystems provides useful biogeographic and ecological hypotheses for explaining the distribution of fungi.
Abstract: Global species richness patterns of soil micro-organisms remain poorly understood compared to macro-organisms. We use a global analysis to disentangle the global determinants of diversity and community composition for ectomycorrhizal (EcM) fungi—microbial symbionts that play key roles in plant nutrition in most temperate and many tropical forest ecosystems. Host plant family has the strongest effect on the phylogenetic community composition of fungi, whereas temperature and precipitation mostly affect EcM fungal richness that peaks in the temperate and boreal forest biomes, contrasting with latitudinal patterns of macro-organisms. Tropical ecosystems experience rapid turnover of organic material and have weak soil stratification, suggesting that poor habitat conditions may contribute to the relatively low richness of EcM fungi, and perhaps other soil biota, in most tropical ecosystems. For EcM fungi, greater evolutionary age and larger total area of EcM host vegetation may also contribute to the higher diversity in temperate ecosystems. Our results provide useful biogeographic and ecological hypotheses for explaining the distribution of fungi that remain to be tested by involving next-generation sequencing techniques and relevant soil metadata.
344 citations
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TL;DR: In this paper, the authors conducted a survey in thirty-four stony riffle stream sites in Ashdown Forest, Sussex, in order to assess the importance of physicochemical factors in determining the distribution of species and the structure of communities.
Abstract: SUMMARY. 1. Invertebrates and fish were surveyed during October 1976 in thirty-four stony riffle stream sites in Ashdown Forest, Sussex.
2. A variety of physicochemical factors were also measured in an attempt to assess the importance of each in determining the distribution of species and the structure of communities.
3. Three analytical techniques—stepwise multiple regression analysis, ordination and community classification—revealed that the structure of these communities was strongly related to variation in stream pH. Acid sites had low numbers of individuals, low species richness and low equitabilities. Summer temperature and stream discharge also appeared to play significant roles. The pattern of catchment land use was shown to have an important bearing on stream pH.
4. In the most acid sites only collectors, shredders and predators occurred. In more basic sites the number of species in collector and predator categories increased and these were joined by grazer/scrapers and filter feeders.
5. A theoretical basis for explaining stream community structure is discussed.
343 citations
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TL;DR: Most affected by logging were species associated with the under- story of tall mature stands especially terrestrial species, members of mixed flocks, and solitary sallying insectivores, all of which decreased by 70% to over 90%.
Abstract: The composition and structure of the bird com- munity were investigated in French Guiana (northeastern Amazonia) I year and 10 years after selective logging and compared with bird community composition and structure in undisturbed primary forest A point-count method was used in which 937 0.25-ha sample quadrats were censused for 20 minutes each. Whereas logging removed little more than 3 trees/ha, 38% of the forest undergrowth was destroyed and a higher proportion of the canopy was opened or dam- aged. An overall 27-33% decrease of species richness, fre- quency, and abundance occurred after logging with a less marked decline of diversity and evenness indices, a substan- tial increase in the proportion of dominant species, and a 45% difference in species composition, weighed by fre- quency, between logged and undisturbed forest communi- ties. Forty-two percent of the species from the primary forest decreased sharply or disappeared after logging and only 34% increased or remained unchanged. Microhabitat selection was the main correlate of sensitivity to disturbance. Most affected by logging were species associated with the under- story of tall mature stands especially terrestrial species, members of mixed flocks, and solitary sallying insectivores, all of which decreased by 70% to over 90%. Most birds as- sociated with canopy, small gaps, and vine tangles declined by only 10-30%. Small frugivores and species associated with clearings or edges increased. Among other factors, phys-
343 citations
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TL;DR: In this paper, the authors investigated tree species composition, richness and diversity in the Amazonian white-water (varzea) forest, looking particularly at: (1) the flood-level gradient, (2) the successional stage (stand age), and (3) the geographical location of the forests.
Abstract: Aim Attention has increasingly been focused on the floristic variation within forests of the Amazon Basin. Variations in species composition and diversity are poorly understood, especially in Amazonian floodplain forests. We investigated tree species composition, richness and a diversity in the Amazonian white-water (varzea) forest, looking particularly at: (1) the flood-level gradient, (2) the successional stage (stand age), and (3) the geographical location of the forests. Location Eastern Amazonia, central Amazonia, equatorial western Amazonia and the southern part of western Amazonia. Methods The data originate from 16 permanent varzea forest plots in the central and western Brazilian Amazon and in the northern Bolivian Amazon. In addition, revised species lists of 28 varzea forest inventories from across the Amazon Basin were used. Most important families and species were determined using importance values. Floristic similarity between plots was calculated to detect similarity variations between forest types and over geographical distances. To check for spatial diversity gradients, a diversity (Fisher) of the plots was correlated with stand age, longitudinal and latitudinal plot location, and flood- level gradient. Results More than 900 flood-tolerant tree species were recorded, which indicates that Amazonian varzea forests are the most species-rich floodplain forests worldwide. The most important plant families recorded also dominate most Neotropical upland forests, and c. 31% of the tree species listed also occur in the uplands. Species distribution and diversity varied: (1) on the flood-level gradient, with a distinct separation between low-varzea forests and high-varzea forests, (2) in relation to natural forest succession, with species-poor forests in early stages of succession and species-rich forests in later stages, and (3) as a function of geographical distance between sites, indicating an increasing a diversity from eastern to western Amazonia, and simultaneously from the southern part of western Amazonia to equatorial western Amazonia. Main conclusions The east-to-west gradient of increasing species diversity in varzea forests reflects the diversity patterns also described for Amazonian terra firme. Despite the fine-scale geomorphological heterogeneity of the floodplains, and despite high disturbance of the different forest types by sedimentation and erosion, varzea forests are dominated by a high proportion of generalistic, widely distributed tree species. In contrast to high-varzea forests, where floristic dissimilarity increases significantly with increasing distance between the sites, low-varzea forests can exhibit high floristic similarity over large geographical distances. The high varzea may be an important transitional zone for lateral immigration of terra firme species to the floodplains, thus contributing to
343 citations