Dallimer M.,University of Sheffield |
Dallimer M.,Center for Macroecology |
Irvine K.N.,De Montfort University |
Skinner A.M.J.,University of Sheffield |
And 7 more authors.
BioScience | Year: 2012
Over half of the world's human population lives in cities, and for many, urban greenspaces are the only places where they encounter biodiversity. This is of particular concern because there is growing evidence that human well-being is enhanced by exposure to nature. However, the specific qualities of greenspaces that offer the greatest benefits remain poorly understood. One possibility is that humans respond positively to increased levels of biodiversity. Here, we demonstrate the lack of a consistent relationship between actual plant, butterfly, and bird species richness and the psychological well-being of urban greenspace visitors. Instead, well-being shows a positive relationship with the richness that the greenspace users perceived to be present. One plausible explanation for this discrepancy, which we investigate, is that people generally have poor biodiversity-identification skills. The apparent importance of perceived species richness and the mismatch between reality and perception pose a serious challenge for aligning conservation and human well-being agendas. © 2012 by American Institute of Biological Sciences. All rights reserved. Source
A pair of elongated, whiplike legs that are actually sophisticated environment sensors distinguish an unusual arachnid known as the whip spider, also called the tailless whip scorpion. Scientists recently described eight new species of this long-legged spider that are native to Brazil, nearly doubling the number of known species in the genus Charinus. Whip spiders use only six of their eight legs for walking, reserving their "whips" — which can reach several times the spiders' body length — for exploring the world around them and locating prey, through a combination of touch and chemical signals. Thanks to the new species discoveries, Brazil now boasts the greatest diversity of whip spiders in the world. But the forest ecosystems where these new species live are threatened by human development, and the researchers suggested that stronger conservation measures are urgently required in order to protect the whip spiders' habitats, and to discover more species before their habitats are destroyed. [Ghoulish Photos: Creepy, Freaky Creatures That Are (Mostly) Harmless] There are 170 known species of whip spiders found all over the world, mostly in tropical areas in the Americas. According to the researchers, the Amazon region — known for its diverse habitats, plants and animals — was long suspected of hiding many more whip spider species than were previously known. Though some whip spiders measure up to 10 inches (25 centimeters) at the fullest extension of their "whips," most are less than 2 inches (5 cm) and are hard to spot, hiding in leaf litter, under stones and tree bark, and in caves. To identify the new species, the researchers turned their attention to specimens from the collections in four Brazilian natural history museum collections: the Butantan Institute, the National Museum of Brazil, the Museu Paraense Emi?lio Goeldi, and the Museum of Zoology of the University of São Paulo. What does it take to describe a new whip spider species? Days, weeks and ultimately months of scrutinizing the spiders' body parts under a microscope and comparing them with other known species in order to find unique and differentiating characteristics, said study co-author Gustavo Silva de Miranda. De Miranda, a graduate student at the Center for Macroecology, Evolution and Climate at the University of Copenhagen, told Live Science that he and his colleagues performed exhaustive inventory of the spiders' features, including the number of segments in the whiplike limbs, the prey-catching spines at the tips of their legs, the groupings of their eyes, and the shape of the females' genitalia, called gonopods. "If we compare all these things and see that it's very unique, then we consider it a new species," de Miranda said. Genital structures turned out to be quite an important point of comparison, de Miranda explained. In each whip spider species, the female's gonopod shape corresponded very specifically to the shape of the male's sperm sac, for perfect alignment. But even as new whip spider species are described, their behavior and habits in the wild remain elusive, de Miranda said. One study, he said, detailed confrontations between males competing for females or territory — the spiders extend and display their head appendages, squaring off without actually fighting, and the loser (the one with the smaller display) retreats after a 20-minute stare-down. "But there is still a lot to be discovered," de Miranda said. "We're trying to understand the evolution of the group, their relationships, how they are so widespread, their morphological evolution." He said this makes it imperative not only to find new species, but to preserve the fragile ecosystems where these spiders live. "If they are not protected, they will vanish from nature," de Miranda said. The findings were published online today (Feb. 17) in the journal PLOS ONE. Follow Mindy Weisberger on Twitterand Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science. Copyright 2016 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
A complex network analysis of hummingbirds and the nectar plants they feed on was used to determine the level of resource specialization in 46 hummingbird communities distributed widely from the Northern USA to Southern Brazil. The study is published today in the journal Proceedings of the Royal Society B by a team of more than 30 scientists. "Using hummingbirds as an example, we have demonstrated a distinct pattern for ecological specialization across a large geographical space. No matter where we look across the Americas it holds true that high food specialization in a community is linked to a high proportion of smaller-ranged species. The explanation for this is thought to be that a stable climate over a long period of time is able to foster both. Patterns like these help us explain and understand biodiversity on a large scale" says lead author and MSc student Jesper Sonne from the Center for Macroecology, Evolution and Climate at the University of Copenhagen. "With this study, we demonstrate that environmental factors such as the climate not only associate with species ranges, but also with local specializations, such as those between hummingbirds and nectar plants. It gives us an insight into how evolutionary and ecological processes jointly structure biological communities in a broad sense." For the hummingbird communities that were investigated, the smallest species ranges were around 40,000 km2 which compares to an area smaller than the size of Denmark, while the largest ranges were about 1,000 times greater. Hummingbirds with even smaller ranges exist but were not included in the study because no information is available on their interactions with plant communities. The study included 130 hummingbird species, representing ca. 40 % of all hummingbird species. The Volcano Hummingbird (Selasphorus flammula), White-bellied Mountain-gem (Lampornis hemileucus) and Fiery-throated Hummingbird (Panterpe insignis) are all examples of species that were classified as smaller-ranged in the study. All three live only in Costa Rica and western Panama and they were found to be locally specialized to feed on particular nectar plants. The results also indicate that aggregations of smaller-ranged species are more vulnerable to environmental change than previously thought. "Species with smaller geographical ranges are naturally more sensitive to environmental change, and if the same community of species is also highly specialized to forage on few food resources, it will be less capable of adapting to a changing environment" says co-author and Assistant Professor Bo Dalsgaard from the Center for Macroecology, Evolution and Climate. Hummingbirds and their nectar plants have long served as model system for examining ecological and evolutionary processes because of their strong mutual dependencies. They are also known to thrive in an array of environments throughout the Americas from Alaska to Tierra del Fuego. Hummingbirds can weigh as little as 2 grams and have extremely diverse bills, adapted to fit their nectar plants. Explore further: High-speed video and artificial flowers shed light on mysteries of hummingbird-pollinated flowers More information: High proportion of smaller-ranged hummingbird species coincides with ecological specialization across the Americas , Proceedings of the Royal Society B: Biological Sciences, rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2015.2512
Bell R.C.,Cornell University |
Drewes R.C.,California Academy of Sciences |
Channing A.,University of the Western Cape |
Gvozdik V.,Academy of Sciences of the Czech Republic |
And 5 more authors.
Journal of Biogeography | Year: 2015
Aim: To infer the colonization history of reed frog species endemic to the oceanic islands of São Tomé and Príncipe, Hyperolius molleri and H. thomensis, we quantified phylogeographical structure in the closely related H. cinnamomeoventris species complex, which is broadly distributed across continental Central Africa. Location: The Lower Guineo-Congolian Forest and the Gulf of Guinea islands of São Tomé and Príncipe, Central Africa. Methods: We combined gene and species tree analyses to investigate diversity and divergence among H. cinnamomeoventris populations, to identify the most likely dispersal route to the islands, and to infer the order in which the islands were colonized. One of the endemics (H. molleri) is distributed on both islands and we quantified genetic divergence between populations. Results: We recovered three clades in H. cinnamomeoventris corresponding to West-Central, North/East-Central and South-Central Africa. The island endemics form a monophyletic group most closely related to the West-Central African H. cinnamomeoventris clade. Populations of H. molleri on São Tomé and Príncipe are reciprocally monophyletic at mitochondrial loci but nuclear gene trees do not support this divergence. Main conclusions: Genetic structure in the H. cinnamomeoventris species complex coincides with biogeographical barriers identified in previous studies of Central African rain forest taxa. Individual gene tree and species tree analyses support a single dispersal event from the Ogooué or Congo river basins (West-Central Africa) to the island of São Tomé, with subsequent divergence within São Tomé and dispersal to Príncipe. © 2014 John Wiley & Sons Ltd. Source
Roura-Pascual N.,University of GironaGirona |
Sanders N.J.,Center for Macroecology |
Hui C.,Stellenbosch UniversityMatieland 7602 South Africa
Global Ecology and Biogeography | Year: 2016
Aim: To examine the relationship between island characteristics (area, distance to the nearest continent, climate and human population size) and ant species richness, as well as the factors underlying global geographical clustering of native and exotic ant composition on islands. Location: One hundred and two islands from 20 island groups around the world. Methods: We used spatial linear models that consider the spatial structure of islands to examine patterns of ant species richness. We also performed modularity analyses to identify clusters of islands hosting a similar suite of species and constructed conditional inference trees to assess the characteristics of islands that explain the formation of these island-ant groups. Results: Island area was the best predictor of ant species richness. However, distance to the nearest continent was an important predictor of native ant species richness, as was human population size for exotic species richness. Native species appear slightly more modulated (i.e. well grouped in species assemblages that are present over a distinct cluster of islands) than are exotic species. Exotic species, while still exhibiting some modularity, tended to be widely distributed among island groups. Interestingly, ocean currents accounted for most of the variation in modularity and thus species composition for both native and exotic ant species. Main conclusions: Contrary to previous work, both native and exotic species appeared to be confined to particular island regions, and patterns in the distribution of both native and exotic species were limited by a similar suite of factors. However, the distribution of exotic ant species appeared to be more influenced by human-related variables and less structured relative to those of native ant species, perhaps due to the long-term (and increasing) influence of human-mediated dispersal that favours exotic species. © 2016 John Wiley & Sons Ltd. Source