Diversity2014, 6(3), 567-578; doi:10.3390/d6030567 - published 29 August 2014 Show/Hide Abstract
Abstract: TheWestern Ghats is a global biodiversity hotspot and home to diverse and unique assemblages of amphibians. Several rivers originate from these mountains and hydropower is being tapped from them. The impacts of hydrological regulation of riparian ecosystems to wildlife and its habitat are poorly documented, and in particular the fate of frog populations is unknown. We examined the effects of dams on riparian frog communities in the Thamirabarani catchment in southern Western Ghats. We used nocturnal visual encounter surveys constrained for time, to document the species richness of frogs below and above the dam, and also at control sites in the same catchment. While we did not find differences in species richness below and above the dams, the frog community composition was significantly altered as a likely consequence of altered flow regime. The frog species compositions in control sites were similar to above-dam sites. Below-dam sites had a distinctly different species composition. Select endemic frog species appeared to be adversely impacted due to the dams. Below-dam sites had a greater proportion of generalist and widely distributed species. Dams in the Western Ghats appeared to adversely impact population of endemic species, particularly those belonging to the genus Nyctibatrachus that shows specialization for intact streams.
Diversity2014, 6(3), 551-566; doi:10.3390/d6030551 - published 7 August 2014 Show/Hide Abstract
Abstract: Jatropha curcas L. (jatropha) is an undomesticated plant that has recently received great attention for its utilization in biofuel production, rehabilitation of wasteland, and rural development. Knowledge of genetic diversity and marker-trait associations is urgently needed for the design of breeding strategies. The main goal of this study was to assess the genetic structure and diversity in jatropha germplasm with co-dominant markers (Simple Sequence Repeats (SSR) and Single Nucleotide Polymorphism (SNP) in a diverse, worldwide, germplasm panel of 70 accessions. We found a high level of homozygosis in the germplasm that does not correspond to the purely outcrossing mating system assumed to be present in jatropha. We hypothesize that the prevalent mating system of jatropha comprise a high level of self-fertilization and that the outcrossing rate is low. Genetic diversity in accessions from Central America and Mexico was higher than in accession from Africa, Asia, and South America. We identified makers associated with the presence of phorbol esters. We think that the utilization of molecular markers in breeding of jatropha will significantly accelerate the development of improved cultivars.
Diversity2014, 6(3), 524-550; doi:10.3390/d6030524 - published 17 July 2014 Show/Hide Abstract
Abstract: We carried out an intensive sampling survey in ancient Lake Ohrid (Macedonia/Albania), covering all seasons, to determine total species number, relative species abundances and spatial distribution of Ostracoda. We identified 32 living species that belong to seven families (Candonidae, Ilyocyprididae, Cyprididae, Leptocytheridae, Limnocytheridae, Cytherideidae, and Darwinulidae) and 15 genera (Candona, Fabaeformiscandona, Candonopsis, Cypria, Cyclocypris, Ilyocypris, Eucypris, Prionocypris, Bradleystrandesia, Herpetocypris, Dolerocypris, Amnicythere, Paralimnocythere, Cytherissa, and Darwinula). Six additional species were identified from empty carapaces and valves. Dominant families in Lake Ohrid were Candonidae and Limnocytheridae, representing 53% and 16% of all species, respectively. Prevalence of species flocks in these two families confirms the “young” ancient status of the lake. Amnicythere displays a preference for oligo-haline to meso-haline waters, but some species are found in saline environments, which suggests Lake Ohrid has a marine history. Recent studies, however, indicate fluvial/glaciofluvial deposition at the onset of Lake Ohrid sedimentation. Candona is the most diverse genus in Lake Ohrid, represented by 12 living species. Paralimnocythere is represented by five living species and all other genera are represented by one or two species. Reports of Candonabimucronata, Ilyocypris bradyi, Eucypris virens, Eucypris sp., Prionocypris zenkeri, Bradleystrandesia reticulate, Herpetocypris sp. 2, and Dolerocypris sinensis are firsts for this lake. Living ostracodes were collected at the maximum water depth (280 m) in the lake (Candona hadzistei, C. marginatoides, C. media, C. ovalis, C. vidua, Fabaeformiscandona krstici, Cypria lacustris, C. obliqua and Amnicythere karamani). Cyprialacustris was overall the most abundant species and Cypriaobliqua displayed the highest abundance at 280 m water depth. Principal environmental variables that influence ostracode distributions in Lake Ohrid are water depth and conductivity. In general, species richness, diversity and evenness were greater in waters <60 m deep, with highest values often found in the littoral zone, at depths <30 m. Candonids, however, displayed highest diversity in the sublittoral (30–50 m) and profundal (50–280 m) zones. The most frequent species encountered are taxa endemic to the lake (14 living species), which have a wide depth range (≤280 m), and display higher abundance with greater water depth. Non-endemic species were rare, limited to water depths <50 m, and were found mainly in the north part of the lake where anthropogenic pressure is high. Several cosmopolitan species were encountered for the first time, which suggests that these widespread species are new arrivals that may replace endemics as human impacts increase.
Diversity2014, 6(3), 500-523; doi:10.3390/d6030500 - published 15 July 2014 Show/Hide Abstract
Abstract: The purpose of this study is to review theoretical and empirical findings in economics with respect to the challenging question of how to manage invasive species. The review revealed a relatively large body of literature on the assessment of damage costs of invasive species; single species and groups of species at different geographical scales. However, the estimated damage costs show large variation, from less than 1 million USD to costs corresponding to 12% of gross domestic product, depending on the methods employed, geographical scale, and scope with respect to inclusion of different species. Decisions regarding optimal management strategies, when to act in the invasion chain and which policy to choose, have received much less attention in earlier years, but have been subject to increasing research during the last decade. More difficult, but also more relevant policy issues have been raised, which concern the targeting in time and space of strategies under conditions of uncertainty. In particular, the weighting of costs and benefits from early detection and mitigation against the uncertain avoidance of damage with later control, when the precision in targeting species is typically greater is identified as a key challenge. The role of improved monitoring for detecting species and their spread and damage has been emphasized, but questions remain on how to achieve this in practice. This is in contrast to the relatively large body of literature on policies for mitigating dispersal by trade, which is regarded as one of the most important vectors for the spread of invasive species. On the other hand, the literature on how to mitigate established species, by control or adaptation, is much more scant. Studies evaluating causes for success or failure of policies against invasive in practice are in principal non-existing.
Diversity2014, 6(3), 415-499; doi:10.3390/d6030415 - published 11 July 2014 Show/Hide Abstract
Abstract: The genus Silene (family Caryophyllaceae) comprises more than 700 species, which are widely distributed in temperate zones of the Northern Hemisphere, but are also present in Africa and have been introduced in other continents. Silene produces a high diversity of secondary metabolites and many of them show interesting biological and pharmacological activities. More than 450 compounds have been isolated; important classes include phytoecdysteroids (which mimic insect molting hormones), triterpene saponins (with detergent properties), volatiles, other terpenoids and phenolics. This review focusses on the phytochemical diversity, distribution of Silene secondary metabolites and their biological activities.
Diversity2014, 6(3), 396-414; doi:10.3390/d6030396 - published 3 July 2014 Show/Hide Abstract
Abstract: Information derived from high spatial resolution remotely sensed data is critical for the effective management of forested ecosystems. However, high spatial resolution data-sets are typically costly to acquire and process and usually provide limited geographic coverage. In contrast, moderate spatial resolution remotely sensed data, while not able to provide the spectral or spatial detail required for certain types of products and applications, offer inexpensive, comprehensive landscape-level coverage. This study assessed using an object-based approach to extrapolate detailed tree species heterogeneity beyond the extent of hyperspectral/LiDAR flightlines to the broader area covered by a Landsat scene. Using image segments, regression trees established ecologically decipherable relationships between tree species heterogeneity and the spectral properties of Landsat segments. The spectral properties of Landsat bands 4 (i.e., NIR: 0.76–0.90 µm), 5 (i.e., SWIR: 1.55–1.75 µm) and 7 (SWIR: 2.08–2.35 µm) were consistently selected as predictor variables, explaining approximately 50% of variance in richness and diversity. Results have important ramifications for ongoing management initiatives in the study area and are applicable to wide range of applications.