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Diversity, Volume 3, Issue 2 (June 2011), Pages 176-295

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Research

Jump to: Review

Open AccessArticle Relative Influence of Prior Life Stages and Habitat Variables on Dragonfly (Odonata: Gomphidae) Densities among Lake Sites
Diversity 2011, 3(2), 200-216; doi:10.3390/d3020200
Received: 10 February 2011 / Revised: 20 March 2011 / Accepted: 24 March 2011 / Published: 14 April 2011
Cited by 2 | PDF Full-text (365 KB) | HTML Full-text | XML Full-text
Abstract
Many aquatic species have discrete life stages, making it important to understand relative influences of the different habitats occupied within those populations. Although population demographics in one stage can carry over to spatially separated life stages, most studies of habitat associations have [...] Read more.
Many aquatic species have discrete life stages, making it important to understand relative influences of the different habitats occupied within those populations. Although population demographics in one stage can carry over to spatially separated life stages, most studies of habitat associations have been restricted to a single life stage. Among Gomphidae dragonflies (Odonata: Anisoptera), recruitment via adult oviposition establishes initial population sizes of the aquatic larvae. However, spatial variability in larval survivorship could obscure the relationship between adult and larval densities. This study uses surveys conducted during 2005 and 2006 of Gomphidae larval, emergence, and adult stages from 22 lake sites in northern Wisconsin, USA, to investigate (1) whether the Gomphidae density of each life stage correlated spatially with that of the preceding life stage and (2) what habitat factors help explain variation in densities at each life stage. Results indicated that adult densities from the previous season helped predict densities of early-instar larvae. This finding suggests that oviposition site selection controlled the local larval distribution more than larval survivorship or movement. Late-instar larval densities helped predict densities of emerging Gomphidae later the same season, suggesting that variation in survivorship of final-instar larvae among sites is small relative to the variation in larval recruitment. This study demonstrates that locations with higher densities of odonates in the water also have higher densities of odonates on land. In addition to the densities of Gomphidae in previous life stages, water clarity helped predict larval densities, and riparian wetland vegetation helped predict emergent dragonfly densities. Full article
(This article belongs to the Special Issue Spatial and Temporal Benthic Diversity Patterns)
Open AccessArticle Mineral Licks as Diversity Hotspots in Lowland Forest of Eastern Ecuador
Diversity 2011, 3(2), 217-234; doi:10.3390/d3020217
Received: 24 December 2010 / Revised: 26 April 2011 / Accepted: 26 April 2011 / Published: 28 April 2011
Cited by 12 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
Mineral licks are sites where a diverse array of mammals and birds consume soil (geophagy) or drink water, likely for mineral supplementation. The diversity of species that visit such sites makes them important for conservation, particularly given that hunters often target animals [...] Read more.
Mineral licks are sites where a diverse array of mammals and birds consume soil (geophagy) or drink water, likely for mineral supplementation. The diversity of species that visit such sites makes them important for conservation, particularly given that hunters often target animals at licks. Use of mineral licks varies among species, with frugivores among the most common visitors but there is considerable temporal and spatial variation in lick use both within and among species. Camera traps triggered by heat and motion were used to document use of mineral licks by birds and non-volant mammals over a four-year period at a lowland forest site in eastern Ecuador. We obtained 7,889 photographs representing 23 mammal species and 888 photographs representing 15 bird species. Activity (photographs/100 trap-days) at the four licks varied from 89 to 292 for mammals and from six to 43 for birds. Tapirs (Tapirus terrestris), peccaries (Pecari tajacu, Tayassu pecari), deer (Mazama americana), and pacas (Cuniculus paca) were the most frequent mammal visitors; guans (Pipile pipile) and pigeons (Columba plumbea) were the most common birds. Use of licks varied diurnally and seasonally but patterns of use varied among species and sites. Mineral licks provide an important resource for many species but further studies are needed to determine the precise benefit(s) obtained and how benefits may vary with diet and other factors, such as rainfall. Full article
(This article belongs to the Special Issue Biodiversity, Conservation and Ecosystem Management)
Open AccessArticle Invasion Age and Invader Removal Alter Species Cover and Composition at the Suisun Tidal Marsh, California, USA
Diversity 2011, 3(2), 235-251; doi:10.3390/d3020235
Received: 1 January 2011 / Revised: 6 May 2011 / Accepted: 10 May 2011 / Published: 19 May 2011
Cited by 2 | PDF Full-text (254 KB) | HTML Full-text | XML Full-text
Abstract
Wetland ecosystems are vulnerable to plant species invasions, which can greatly alter species composition and ecosystem functioning. The response of these communities to restoration can vary following invader removal, but few studies have evaluated how recent and long-term invasions can affect the [...] Read more.
Wetland ecosystems are vulnerable to plant species invasions, which can greatly alter species composition and ecosystem functioning. The response of these communities to restoration can vary following invader removal, but few studies have evaluated how recent and long-term invasions can affect the plant community’s restoration potential. Perennial pepperweed (Lepidium latifolium) has invaded thousands of hectares of marshland in the San Francisco Estuary, California, United States of America, while the effects of invasion and removal of this weed remain poorly studied. In this study, perennial pepperweed was removed along a gradient of invasion age in brackish tidal marshes of Suisun Marsh, within the Estuary. In removal plots, resident plant cover significantly increased during the 2-year study period, particularly in the densest and oldest parts of the perennial pepperweed colonies, while species richness did not change significantly. In bare areas created by removal of perennial pepperweed, recolonization was dominated by three-square bulrush (Schoenoplectus americanus). Ultimately, removal of invasive perennial pepperweed led to reinvasion of the resident plant community within two years. This study illustrates that it is important to consider invasion age, along with exotic species removal, when developing a restoration strategy in wetland ecosystems. Full article
(This article belongs to the Special Issue Biological Invasion)
Open AccessArticle Using Maximum Entropy Modeling for Optimal Selection of Sampling Sites for Monitoring Networks
Diversity 2011, 3(2), 252-261; doi:10.3390/d3020252
Received: 14 April 2011 / Revised: 27 April 2011 / Accepted: 10 May 2011 / Published: 26 May 2011
Cited by 1 | PDF Full-text (359 KB) | HTML Full-text | XML Full-text
Abstract
Environmental monitoring programs must efficiently describe state shifts. We propose using maximum entropy modeling to select dissimilar sampling sites to capture environmental variability at low cost, and demonstrate a specific application: sample site selection for the Central Plains domain (453,490 km2 [...] Read more.
Environmental monitoring programs must efficiently describe state shifts. We propose using maximum entropy modeling to select dissimilar sampling sites to capture environmental variability at low cost, and demonstrate a specific application: sample site selection for the Central Plains domain (453,490 km2) of the National Ecological Observatory Network (NEON). We relied on four environmental factors: mean annual temperature and precipitation, elevation, and vegetation type. A “sample site” was defined as a 20 km × 20 km area (equal to NEON’s airborne observation platform [AOP] footprint), within which each 1 km2 cell was evaluated for each environmental factor. After each model run, the most environmentally dissimilar site was selected from all potential sample sites. The iterative selection of eight sites captured approximately 80% of the environmental envelope of the domain, an improvement over stratified random sampling and simple random designs for sample site selection. This approach can be widely used for cost-efficient selection of survey and monitoring sites. Full article
Open AccessArticle Spatial Identification of Statewide Areas for Conservation Focus in New Mexico: Implications for State Conservation Efforts
Diversity 2011, 3(2), 275-295; doi:10.3390/d3020275
Received: 4 May 2011 / Accepted: 13 June 2011 / Published: 16 June 2011
Cited by 3 | PDF Full-text (1339 KB) | HTML Full-text | XML Full-text
Abstract
Landscape scale conservation planning efforts have been in place for the past several decades to maintain biodiversity. Objectives of past efforts have been to identify areas to create reserves based on species diversity, land ownership, and landscape context. Risk analysis has not [...] Read more.
Landscape scale conservation planning efforts have been in place for the past several decades to maintain biodiversity. Objectives of past efforts have been to identify areas to create reserves based on species diversity, land ownership, and landscape context. Risk analysis has not often been included in these spatial analyses. Datasets such as the Southwest Regional Gap Analysis (SWReGAP) are now available as are processes that allow risk analysis to be viewed in a spatial context in relations to factors that affect habitats over broad scales. We describe a method to include four spatial datasets to provide coarse scale delineation on areas to focus conservation including species numbers, key habitats, land management and factors that influence habitats. We used the SWReGAP management status dataset to identify management categories for long-term intent of management for biodiversity. The New Mexico Department of Game and Fish identified a set of 290 Species of Greatest Conservation Need (SGCN). Species occurrences for these species were associated with hydrologic unit codes from the National Hydrography Dataset (NHD). Key habitats were identified by using the SWReGAP land cover dataset and NHD derivatives. Factors that influence habitats were identified and scored for 89 land cover types and 23 aquatic habitats identified by the NMDGF. Our final model prioritizes landscapes that are within key habitats, have high numbers of terrestrial and aquatic Species of Greatest Conservation Need taxa, may be potentially altered by multiple effects that influence habitats, and lack long-term legally-binding management plans protecting them from anthropogenic degradation. Similar to other efforts, riparian and aquatic habitats were identified as the most important for conservation. This information may be displayed spatially, allowing land managers and decision makers to understand the ecological context where multiple effects of potential factors may influence some habitats greater than others, and repeat process with CWCS revisions. Full article
(This article belongs to the Special Issue Biodiversity, Conservation and Ecosystem Management)

Review

Jump to: Research

Open AccessReview Diversity Patterns of Benthic Macrofauna Caused by Marine Fish Farming
Diversity 2011, 3(2), 176-199; doi:10.3390/d3020176
Received: 8 October 2010 / Revised: 25 March 2011 / Accepted: 25 March 2011 / Published: 14 April 2011
Cited by 9 | PDF Full-text (655 KB) | HTML Full-text | XML Full-text
Abstract
This paper reviews the patterns observed in the diversity and structure of the macrofauna benthic community under the influence of fish farming. First, we explain the effects of organic enrichment on the sediment and the consequences for the inhabiting communities. We describe [...] Read more.
This paper reviews the patterns observed in the diversity and structure of the macrofauna benthic community under the influence of fish farming. First, we explain the effects of organic enrichment on the sediment and the consequences for the inhabiting communities. We describe the diversity trends in spatial and temporal gradients affected by fish farming and compare them with those described by the Pearson and Rosenberg model. We found that in general terms, the trends of diversity and other community parameters followed the Pearson and Rosenberg model but they can vary to some extent due to sediment local characteristics or to secondary disturbances. We also show the different mechanisms by which wild fish can affect macrofauna diversity patterns under fish farming influence. In addition, we comment the importance of the macrofauna diversity in the ecosystem functions and propose some guidelines to measure functional diversity related to relevant processes at ecosystem level. We propose more research efforts in the main topics commented in this review to improve management strategies to guarantee a good status of the diversity and ecosystem functioning of sediments influenced by fish farming. Full article
(This article belongs to the Special Issue Spatial and Temporal Benthic Diversity Patterns)
Open AccessReview Ocean Acidification and Coral Reefs: An Emerging Big Picture
Diversity 2011, 3(2), 262-274; doi:10.3390/d3020262
Received: 21 March 2011 / Revised: 9 May 2011 / Accepted: 23 May 2011 / Published: 30 May 2011
Cited by 17 | PDF Full-text (153 KB) | HTML Full-text | XML Full-text
Abstract
This article summarises the sometimes controversial contributions made by the different sciences to predict the path of ocean acidification impacts on the diversity of coral reefs during the present century. Although the seawater carbonate system has been known for a long time, [...] Read more.
This article summarises the sometimes controversial contributions made by the different sciences to predict the path of ocean acidification impacts on the diversity of coral reefs during the present century. Although the seawater carbonate system has been known for a long time, the understanding of acidification impacts on marine biota is in its infancy. Most publications about ocean acidification are less than a decade old and over half are about coral reefs. Contributions from physiological studies, particularly of coral calcification, have covered such a wide spectrum of variables that no cohesive picture of the mechanisms involved has yet emerged. To date, these studies show that coral calcification varies with carbonate ion availability which, in turn controls aragonite saturation. They also reveal synergies between acidification and the better understood role of elevated temperature. Ecological studies are unlikely to reveal much detail except for the observations of the effects of carbon dioxide springs in reefs. Although ocean acidification events are not well constrained in the geological record, recent studies show that they are clearly linked to extinction events including four of the five greatest crises in the history of coral reefs. However, as ocean acidification is now occurring faster than at any know time in the past, future predictions based on past events are in unchartered waters. Pooled evidence to date indicates that ocean acidification will be severely affecting reefs by mid century and will have reduced them to ecologically collapsed carbonate platforms by the century’s end. This review concludes that most impacts will be synergistic and that the primary outcome will be a progressive reduction of species diversity correlated with habitat loss and widespread extinctions in most metazoan phyla. Full article
(This article belongs to the Special Issue Coral Reef Diversity: Climate Change and Coral Reef Degradation)

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