Search results for "RANGE"

Assessing sampling coverage of species distribution in biodiversity databases

2019

Abstract Aim Biodiversity databases are valuable resources for understanding plant species distributions and dynamics, but they may insufficiently represent the actual geographic distribution and climatic niches of species. Here we propose and test a method to assess sampling coverage of species distribution in biodiversity databases in geographic and climatic space. Location Europe. Methods Using a test selection of 808,794 vegetation plots from the European Vegetation Archive (EVA), we assessed the sampling coverage of 564 European vascular plant species across both their geographic ranges and realized climatic niches. Range maps from the Chorological Database Halle (CDH) were used as bac…

Gibberellic acid in Citrus spp. flowering and fruiting: A systematic review

2019

[EN] Background In Citrus spp., gibberellic acid (GA) has been proposed to improve different processes related to crop cycle and yield. Accordingly, many studies have been published about how GA affects flowering and fruiting. Nevertheless, some such evidence is contradictory and the use of GA applications by farmers are still confusing and lack the expected results. Purpose This review aims to collate, present, analyze and synthesize the most relevant empirical evidence to answer the following questions: (i) how does gibberellic acid act on flowering and fruiting of citrus trees?; (ii) why is all this knowledge sometimes not correctly used by farmers to solve yield problems relating to flo…

Covariation in population trends and demography reveals targets for conservation action

2021

Wildlife conservation policies directed at common and widespread, but declining, species are difficult to design and implement effectively, as multiple environmental changes are likely to contribute to population declines. Conservation actions ultimately aim to influence demographic rates, but targeting actions towards feasible improvements in these is challenging in widespread species with ranges that encompass a wide range of environmental conditions. Across Europe, sharp declines in the abundance of migratory landbirds have driven international calls for action, but actions that could feasibly contribute to population recovery have yet to be identified. Targeted actions to improve condit…

Halophila stipulacea descriptors in the native area (Red Sea): A baseline for future comparisons with native and non-native populations

2018

Abstract Halophila stipulacea is a small tropical seagrass species native to the Red Sea. Due to its invasive character, there is growing interest in understanding its ability to thrive in a broad range of ecological niches. We studied temporal (February 2014 and July 2014), depth (5, 9, 18 m) and spatial (NB and SB) related dynamics of H. stipulacea meadows in the northern Gulf of Aqaba. We evaluated changes in density, morphometry, biomass, and biochemical parameters alongside the reproductive effort. In both sites, maximal growth and vegetative performance occurred in the summer with a marked increase of 35% in shoot density and 18% in biomass; PAR reduction with season and depth induced…

2018

Marine life of the Southern Ocean has been facing environmental changes and the direct impact of human activities during the past decades. Benthic communities have particularly been affected by such changes although we only slowly understand the effect of environmental changes on species physiology, biogeography, and distribution. Species distribution models (SDM) can help explore species geographic responses to main environmental changes. In this work, we modeled the distribution of four echinoid species with contrasting ecological niches. Models developed for [2005-2012] were projected to different time periods, and the magnitude of distribution range shifts was assessed for recent-past c…

Potential of contemporary evolution to erode fishery benefits from marine reserves

2016

Marine reserves are valued for their ecological role: protecting fish populations from overharvesting while, at the same time, potentially maintaining fisheries yields via recruitment effects (net export of pelagic eggs and larvae) and spillover (net export of post-settled juveniles and mature fish) across reserve borders. Focussing on the spillover effect, we argue that when fitness of the protected individuals depends on the relative size of their home ranges compared to the reserve size, and home range size is a property of the individuals, rapid local adaptation might occur in favour of individuals with smaller home ranges. Individuals that avoid fishing mortality by spending most of th…

SPACE USE, CIRCADIAN ACTIVITY PATTERN, AND MATING SYSTEM OF THE NOCTURNAL TREE RAT THALLOMYS NIGRICAUDA

2004

We present results of a radiotracking study of the black-tailed tree rat Thallomys nigricauda, based on 3 males and 4 females in the breeding season and 2 males and 5 females in the nonbreeding season. The study was conducted in the southern Kalahari thornveld, South Africa, a savanna landscape of acacia trees and patchy acacia bush. Nocturnal activity patterns, vegetation use, space use, and interactions were followed for 8–17 days. During the breeding season, males were active with 2 synchronous activity peaks shortly after sunset and late at night. Home ranges included the nests of 8–10 females, 6 different daytime resting places, and 3–5 areas of high activity. Males were mobile within …

FLUCTUATING TEMPERATURE LEADS TO EVOLUTION OF THERMAL GENERALISM AND PREADAPTATION TO NOVEL ENVIRONMENTS

2013

Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms' ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…

A novel method to predict dark diversity using unconstrained ordination analysis

2019

[Questions] Species pools are the product of complex ecological and evolutionary mechanisms, operating over a range of spatial scales. Here, we focus on species absent from local sites but with the potential to establish within communities — known as dark diversity. Methods for estimating dark diversity are still being developed and need to be compared, as well as tested for the type, and amount, of reference data needed to calibrate these methods. [Location] South Bohemia (48°58′ N, 14°28′ E) and Železné Hory (49°52′ N, 15°34′ E), Czech Republic. [Method] We compared a widely accepted algorithm to estimate species pools (Beals smoothing index, based on species co-occurrence) against a nove…

2018

Odonate (damselfly and dragonfly) species richness and species occupancy frequency distributions (SOFDs) were analyzed in relation to geographical location in standing waters (lakes and ponds) in Fennoscandia, from southern Sweden to central Finland. In total, 46 dragonfly and damselfly species were recorded from 292 waterbodies. Species richness decreased to the north and increased with waterbody area in central Finland, but not in southern Finland or in Sweden. Species occupancy ranged from 1 up to 209 lakes and ponds. Over 50% of the species occurred in <10% of the waterbodies, although this proportion decreased to the north. In the southern lakes and ponds, none of the species occurred …