Search results for "ABUNDANCE"

2017

Because they can form seasonal mixed-species groups during mating and maternal care, bats are exciting models for studying interspecific hybridization. Myotis myotis and M. blythii are genetically close and morphologically almost identical, but they differ in some aspects of their ecology and life-history traits. When they occur in sympatry, they often form large mixed maternity colonies, in which their relative abundance can vary across time due to a shift in the timing of parturition. For the first time, we used non-invasive genetic methods to assess the hybridization rate and colony composition in a maternity colony of M. myotis and M. blythii located in the French Alps. Bat guano was co…

Testing the enemy release hypothesis: abundance and distribution patterns of helminth communities in grey mullets (Teleostei: Mugilidae) reveal the s…

2017

International audience; The abundance and aggregation patterns of helminth communities of two grey mullet hosts, Liza haematocheilus and Mugil cephalus, were studied across 14 localities in Atlantic and Pacific marine areas. The analysis matched parasite communities of (i) L. haematocheilus across its native and introduced populations (Sea of Japan and Sea of Azov, respectively) and (ii) the introduced population of L. haematocheilus with native populations of M. cephalus (Mediterranean, Azov-Black and Japan Seas). The total mean abundance (TMA), as a feature of the infection level in helminth communities, and slope b of the Taylor’s power law, as a measure of parasite aggregation at the in…

Temperature and pH define the realised niche space of arbuscular mycorrhizal fungi

2021

Made available in DSpace on 2021-06-25T11:52:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-04 European Regional Development Fund (Centre of Excellence EcolChange) University of Tartu (Estonian Research Council ) Moscow State University Natural Sciences and Engineering Research Council of Canada Discovery Grant Russian Science Foundation Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Swedish Research Council (Vetenskapsradet) The arbuscular mycorrhizal (AM) fungi are a globally distributed group of soil organisms that play critical roles in ecosystem function. However, the ecological niches of individual AM fungal taxa are poorly understood. We collected > 300 s…

Intensive Management and Natural Genetic Variation in Red Deer (Cervus elaphus)

2017

The current magnitude of big-game hunting has outpaced the natural growth of populations, making artificial breeding necessary to rapidly boost hunted populations. In this study, we evaluated if the rapid increase of red deer (Cervus elaphus) abundance, caused by the growing popularity of big-game hunting, has impacted the natural genetic diversity of the species. We compared several genetic diversity metrics between 37 fenced populations subject to intensive management and 21 wild free-ranging populations. We also included a historically protected population from a national park as a baseline for comparisons. Contrary to expectations, our results showed no significant differences in geneti…

Estimation of water vole abundance by using surface indices

1995

A method to estimate the abundance of the fossorial form of the water vole Arvicola terrestris scherman (Shaw, 1801) has been developed, by using surface indicies. Results are compared to the standard method of estimation using trap lines.

ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest

2017

South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on‐line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeogr…

The interplay of nested biotic interactions and the abiotic environment regulates populations of a hypersymbiont.

2018

1.The role of biotic interactions in shaping the distribution and abundance of species should be particularly pronounced in symbionts. Indeed, symbionts have a dual niche composed of traits of their individual hosts and the abiotic environment external to the host, and often combine active dispersal at finer scales with host‐ mediated dispersal at broader scales. The biotic complexity in the determinants of species distribution and abundance should be even more pronounced for hypersymbionts (symbionts of other symbionts). 2.We use a chain of symbiosis to explore the relative influence of nested biotic interactions and the abiotic environment on occupancy and abundance of a hypersymbiont. 3.…

Fuzzy quantification of common and rare species in ecological communities (FuzzyQ)

2021

International audience; Most species in ecological communities are rare, whereas only a few are common. This distributional paradox has intrigued ecologists for decades but the interpretation of species abundance distributions remains elusive.We present Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ) as an R package. FuzzyQ shifts the focus from the prevailing species-categorization approach to develop a quantitative framework that seeks to place each species along a rarity-commonness gradient. Given a community surveyed over a number of sites, quadrats, or any other convenient sampling unit, FuzzyQ uses a fuzzy clustering algorithm that estimates a probab…

Long-term changes in winter abundance of the barbastelle Barbastella barbastellus in Poland and the climate change - Are current monitoring schemes s…

2020

Warmer winters may lead to changes in the hibernation behaviour of bats, such as the barbastelle Barbastella barbastellus, which prefers to hibernate at low temperatures. The species is also known for its large annual fluctuations in the number of wintering individuals, so inference about population trends should be based on long-term data. Prior to 2005, analyses indicated stable or even increasing barbastelle population in Poland. We analysed the results of 13 winter bat counts (2005–2017) of the species from 15 of the largest hibernacula, and additional site of 47 small bunkers, in Poland. The total number of wintering individuals remained stable during the study period, because the barb…

Substantial decline of Northern European peatland bird populations: Consequences of drainage

2017

Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peat land species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habit…