Diversity2013, 5(4), 811-823; doi:10.3390/d5040811 - published online 2 December 2013 Show/Hide Abstract
Abstract: The “integrated evolutionary speed hypothesis” proposes that the rate of genetic evolution influences all major biogeographical patterns of diversity including those associated with temperature, water availability, productivity, spatial heterogeneity and area. Consistent with this theory, rates of genetic evolution correspond with patterns of diversity and diversification. Here we review the mechanisms that have been proposed to explain these biogeographic patterns in rates of genetic evolution. Tests of several proposed mechanisms have produced equivocal results, whereas others such as those invoking annual metabolic activity, or a “Red Queen” effect, remain unexplored. However, rates of genetic evolution have been associated with both productivity mediated rates of germ cell division and active metabolic rates and these explanations therefore justify further empirical investigation.
Diversity2013, 5(4), 796-810; doi:10.3390/d5040796 - published online 22 November 2013 Show/Hide Abstract
Abstract: We used the mitochondria DNA COI (cytochrome c oxidase subunit I) sequence as a genetic marker to analyze the population genetic structure of two species of freshwater copepods, Neodiaptomus schmackeri (Poppe and Richard, 1892) and Mongolodiaptomus birulai (Rylov, 1922) from Taiwan. Four populations with 51 individuals of N. schmackeri and five populations with 65 individuals of M. birulai were included. We compared the nucleotide sequences of a 635-bp fragment of the COI gene of N. schmackeri and a 655-bp fragment of the COI gene of M. birulai, and eight and 14 unique haplotypes were recorded, respectively. Tseng-Wen reservoir and Wu-San-Tao reservoir are linked by a channel, and the gene flow between them was unrestricted (Fst = 0.058; Nm = 4.04; Fst,population differentiation parameter; Nm, the number of succesfull migrants per generation); the gene flow between all other populations of both species was restricted (Fst = 0.4–0.99; Nm = 0–0.37). Based on the COI gene diversification pattern, we suggest that most populations of N. schmackeri and M. birulai are isolated from each other. According to the neighbor-joining tree and the minimum spanning network (MSN), the species have similar metapopulation genetic structures. Genetic distance was not found to be correlated with geographical distance. The genetic diversification pattern was not shown to be comparable with geographical isolation owing to long-distance separation. The genetic structure of the present populations may result from serial extinction and redistribution of the populations formed in each reservoir relative to time. Human activity in the reservoirs with regards to water resource management and the fishery industry also exerts an effect on population redistribution.
Diversity2013, 5(4), 779-795; doi:10.3390/d5040779 - published online 13 November 2013 Show/Hide Abstract
Abstract: Using six years of remote sensing data, we estimated land and forest degradation inside 1788 protected areas across 19 countries in Latin America. From 2004–2009, the rate of land and forest degradation increased by 250% inside the protected areas, and the land and forest degradation totaled 1,097,618 hectares. Of the protected areas in our dataset, 45% had land and forest degradation. There were relatively large variations by major habitat type, with flooded grasslands/savannas and moist broadleaf forest protected areas having the highest rates of degradation. We found no association between a country’s rate of land and forest degradation inside protected areas and Gross Domestic Product (GDP) per capita, GDP growth, or rural population density. We found significant, but weak, associations between the rate of land and forest degradation inside protected areas and a country’s protected area system funding, the size of the protected area, and one International Union for the Conservation of Nature (IUCN) management category. Our results suggest a high degree of heterogeneity in the variables impacting land and forest degradation inside protected areas in Latin America, but that the targeting of protected area investments on a continental scale is plausible.
Diversity2013, 5(4), 767-778; doi:10.3390/d5040767 - published online 22 October 2013 Show/Hide Abstract
Abstract: Domestic gardens may play a vital role in supporting urban insect biodiversity, despite their small size. This paper assesses the abundance, diversity and distribution of insects in urban domestic gardens in the tropics, through a study in the rapidly expanding Indian city of Bangalore. Fifty domestic gardens were studied using a combination of light traps and pitfall traps. We recorded a large number of insects, 2,185 insects from 10 orders, of which ants, bugs, beetles and flies were the most common. We found 25 species of trees (from 160 individuals) and 117 species of herbs and shrubs in the 50 sampled domestic gardens. The number of insect orders encountered was significantly related to the number of tree and herb/shrub species. Garden management practices also influenced the abundance and richness of insect orders. Thus, greater numbers of insects were observed in gardens with a greater proportion of bare soil relative to grass area and with less intensive weeding practices. More insect orders were encountered in gardens with a composting pit. Insect numbers were significantly reduced in gardens subjected to pesticide application. Most residents avoided application of pesticides and herbicides, citing health concerns.
Diversity2013, 5(4), 750-766; doi:10.3390/d5040750 - published online 21 October 2013 Show/Hide Abstract
Abstract: One of the biggest threats to coffee growers in East Africa are emerging vascular wilt diseases (tracheomycosis) caused by Fusarium spp. Many Trichoderma species are known to be natural antagonists of these pathogens and are widely used in biological control of fungal plant diseases. More recently, several Trichoderma spp., which exhibited high antifungal activity have been isolated as endophytes. Consequently, we have investigated the presence and the antagonistic activity of endophytic Trichoderma isolated from roots of healthy coffee plants (Coffea arabica) from the major coffee growing regions of Ethiopia. Our results showed that community of Trichoderma spp. in roots of C. arabica contains fungi from coffee rhizosphere, as well as putatively obligate endophytic fungi. The putatively “true” endophytic species, until now, isolated only from coffee plant ecosystems in Ethiopia and recently described as T. flagellatum and novel T. sp. C.P.K. 1812 were able to antagonize Fusarium spp., which cause coffee tracheomycosis. Moreover, we found that strains of these species are also highly antagonistic against other phytopathogenic fungi, such as Alternaria alternata, Botryotinia fuckeliana (anamorph: Botrytis cinerea), and Sclerotinia sclerotiorum.
Diversity2013, 5(4), 734-749; doi:10.3390/d5040734 - published online 30 September 2013 Show/Hide Abstract
Abstract: Understanding mechanisms underlying insects’ host choice and plant susceptibility is important to the study of plant-insect interactions in general, and in the context of plant invasions. This study investigates the oviposition and feeding choices of the specialist weevil Exapion ulicis on the invasive plant species Ulex europaeus, gorse. To do so, we studied the oviposition and feeding preferences of the weevil in choice experiments, using pods and flowers, respectively, from gorses grown in a common garden. The plants used came from regions with different infestation histories: Brittany and Scotland belong to the native range, where the weevil is present, while Reunion and New Zealand belong to the invasive range, where the weevil was not initially introduced with gorse. Results of these experiments suggest that the oviposition choice of E. ulicis females is driven by cues located at the surface of pods and inside them, including pod size and pod seed content. Feeding-choice experiments showed a different pattern of preference compared to oviposition. Taken together with previous studies, our results reveal that E. ulicis uses several traits to choose its host, including whole-plant traits, flower traits and pod traits.