Mussels and Local Conditions Interact to Influence Microbial Communities in Mussel Beds

Microbiomes are increasingly recognized as widespread regulators of function from individual organism to ecosystem scales. However, the manner in which animals influence the structure and function of environmental microbiomes has received considerably less attention. Using a comparative field study, we investigated the relationship between freshwater mussel microbiomes and environmental microbiomes. We used two focal species of unionid mussels, Amblema plicata and Actinonaias ligamentina, with distinct behavioral and physiological characteristics. Mussel microbiomes, those of the shell and biodeposits, were less diverse than both surface and subsurface sediment microbiomes. Mussel abundance was a significant predictor of sediment microbial community composition, but mussel species richness was not. Our data suggest that local habitat conditions which change dynamically along streams, such as discharge, water turnover, and canopy cover, work in tandem to influence environmental microbial community assemblages at discreet rather than landscape scales. Further, mussel burrowing activity and mussel shells may provide habitat for microbial communities critical to nutrient cycling in these systems.

Characteristics of Central American brocket deer resting sites in a tropical mountain cloud forest in eastern Mexico

The Central American brocket deer is a vulnerable species. Geographically isolated populations have been affected by poaching and habitat fragmentation, leading to local extinctions. It is therefore important to understand this species’ habitat characteristics, particularly of resting sites, which play a crucial role in survival and fitness. We describe the characteristics and distribution patterns of Central American brocket deer resting sites at the microhabitat and landscape scales in San Bartolo Tutotepec, Hidalgo, México. We conducted eight bimonthly field surveys between November 2017 and March 2019, consisting of 32 transects of 500 m length to search for fecal pellets, footprints, scrapes, and browsed plants. At each resting site we identified, we measured canopy closure, horizontal thermal cover, protection from predators for fawns and adults, escape routes, slope from the ground, presence of scrapes, cumulative importance value of the edible plant species, and distance from the resting site to the nearest water resource to characterize the site at the microhabitat scale. At the landscape scale, we identified the type of biotope, elevation, aspect, and slope. We compared all of these parameters from resting sites with a paired randomly selected site to serve as a control. We performed a multiple logistic regression to identify the parameters associated with the resting sites and a point pattern analysis to describe their distribution. We characterized 43 resting sites and their corresponding control plots. At the microhabitat scale, resting sites were associated with higher vertical thermal cover, more concealment cover, more escape routes, more edible plant species, higher slope from the ground, and closer distance to water resources. At the landscape scale, resting sites were associated with beech forest, oak forest, secondary forest, and ravine biotopes and negatively associated with pine forest, houses, and roads. Resting sites had an aggregated spatial pattern from 0 to 900 m, but their distribution was completely random at larger scales. Our study revealed that Central American brocket deer selected places with specific characteristics to rest, at both microhabitat and landscape scales. We therefore suggest that existing habitat be increased by reforesting with native species—particularly Mexican beech forest and oak forest—to improve the deer’s conservation status in the study area.

Drought-induced Forest Dieback Increases Taxonomic and Functional Diversity But Not Phylogenetic Diversity of Saproxylic Beetles at Both Local and Landscape Scales

Context: Forest ecosystems worldwide are facing increasing drought-induced dieback, causing mortality patches across the landscape at multiple scales. This increases the supply of biological legacies and differentially affects forest insect communities.Objectives: We analysed the relative effects of local- and landscape-level dieback on local saproxylic beetle assemblages. We assessed how classic concepts in spatial ecology (e.g. habitat-amount and habitat-patch hypotheses) are involved in relationships between multi-scale spatial patterns of available resources and local communities.Methods: We sampled saproxylic beetle assemblages in commercial fir forests in the French highlands. Through automatic aerial mapping, we used dead tree crowns to assess dieback levels at several nested spatial scales. We analysed beetle taxonomic, phylogenetic and functional diversity related to differing levels of multi-scale dieback.Results: In line with the habitat-amount hypothesis, taxonomic and functional diversity, but not phylogenetic diversity, of beetle assemblages significantly benefitted from forest dieback, at both local and landscape scales. Very few single or interaction effects were detected in the multiplicative models combining local and landscape variables, though a significant positive effect of landscape-scale dieback on the abundance of cavity- and fungus-dwelling species was consistent with a spill-over effect. Increased landscape-scale dieback also caused a functional specialisation of beetle assemblages, favouring those related to large-diameter, well-decayed deadwood.Conclusions: Increasing tree mortality under benign neglect provides conservation benefits by heterogenising the forest landscape and enhancing deadwood habitats. Legacy retention practices could take advantage of unharvested, declining forest stands to promote species richness and functional diversity within conventionally managed forest landscapes.

Local and landscape features constrain the trait and taxonomic diversity of urban bees

Context There is concern that urbanization threatens bees, a diverse group of economic importance. The impact of urbanization on bees is likely mediated by their phenotypic traits. Objectives We examine how urban cover and resource availability at local and landscape scales influences both species taxonomic and functional diversity in bees. Methods We used a combination of aerial netting and pan traps across six sampling periods to collect wild bees in 18 urban gardens spanning more than 125 km of the California central coast. We identified 3537 specimens to genus and, when possible, to species to obtain species richness and abundance at each site. For each species we measured a suite of bee traits, including body size, sociality, nesting location, nesting behavior, pollen-carrying structure, parasitism, and lecty. Results We found that increased garden size was positively associated with bee species richness and abundance. Somewhat counterintuitively, we found that urban cover surrounding gardens (2 km) was positively associated with bee species richness. Urban cover was also associated with the prevalence of certain bee traits, such as bees that excavate nests over those who rent, and bees with non-corbiculate structures. We suggest that urban habitats such as gardens can host a high number of bee species, but urbanization selects for species with specific traits. Conclusions These findings illustrate that local and landscape features both influence bee abundance, species richness, and the frequency of specific traits. We highlight the importance of trait-based approaches for assessing biodiversity in urban landscapes, and suggest conceptualizing urbanization as a process of habitat change rather than habitat loss.

Water chemistry and not urbanization influences community structure of non-marine Ostracoda (Crustacea) in northern Belgium

Urbanization is one of the major causes of the destruction of natural habitats in the world. Cities are urban heat islands and can thus significantly influence populations of plants and animals. The research project SPEEDY investigated the effects of urbanization in northern Belgium with a nested sampling design at local and landscape scales for a variety of organisms. Here, we tested the effects of urbanization on non-marine ostracod communities, sampling 81 small pools in three urbanization categories, as defined by percentage built up cover (low, intermediate, high). We identified 17 ostracod species, together occurring in 60 of the 81 sampled pools. We found that urbanization per se had no significant effect on ostracod communities. Of all the measured local factors, ammonium and total phosphorus concentrations had a significant effect on the community structure. In contrast, water temperature had no significant effect, most likely because the ostracod species found in northern Belgium in the present survey mostly have wide temperature tolerances.

Including Condition into Ecological Maps Changes Everything—A Study of Ecological Condition in the Conterminous United States

In 2021, the Biden administration signed an executive order to protect 30% of American lands by 2030. Accomplishing this ambitious goal in the U.S. requires understanding the relative contribution of public and private lands toward supporting biodiversity. New approaches are needed because existing approaches focus on quantity of habitat without incorporating quality. To fill this need, we developed a 30 m resolution national habitat condition index (HCI) that integrates quality and quantity measures of habitat. We hypothesized that including an evaluation of the quality of habitat at landscape scales, both in conservation-focused preserves and working lands would provide a better assessment of the value of geographies for conservation. We divided the conterminous U.S. by major land cover type and into natural and cultivated lands and then spatially mapped multiple anthropogenic stressors, proximity to aquatic habitat, and vegetation departure from expected natural disturbance regimes. Each map layer was then scored for site impact and distance decay and combined into a final national index. Field observations providing scored relative ecological conditions were used for HCI calibration and validation at both CONUS and regional scales. Finally, we evaluate lands by management (conservation versus working lands) and ownership (public versus private) testing the value of these lands for conservation. While we found regional differences across CONUS, functional habitat was largely independent of protection status: working lands provide clear habitat and other values. These results are relevant for guiding strategies to achieve the U.S. 30 by 30 goals. Where similar data exist in other countries, analogous modeling could be used to meet their national conservation commitments.

Advantage and Disadvantage of Global and Local Climate Datasets on Modeling Species Distribution at Continental and Landscape Scales

Species distribution model based on global and local climate datasets were hypothesized to have advantages on projecting distribution range at continental and landscape scales, respectively. Random Forest (RF) and principle components analysis (PCA) aimed to project potential distribution range and to construct climate space of Bretschneidera sinensis in continental East Asia (CEA) and northern Taiwan (NTWN) based on the WorldClim and local climate datasets. Geographical extent of the endangered species at continental scale was available to be projected by RF based on the WorldClim dataset, whereas isolation and fragmentation of natural habitat had not been presented by the projection map in CEA. At landscape scale, projection map of RF in NTWN based on the WorldClim dataset presented gridded distribution far from empirical distribution pattern, while that based on local climate dataset presented a distribution pattern relevant to elevation and topography. PCA had revealed climate differentiation between continental and island populations. Evidently, local climate dataset is essential for identifying ecological adaptation of island population at geographical margin of the endangered species. Meteorological data interpolated and altitudinal adjusted by empirical elevation lapse rate calculated for each watershed had captured climate heterogeneity in mountainous area, whereas it generated huge number of gridded cells that is not available to expand this method to continental region. Global climate dataset has the advantage on modeling geographical extent of plant species at continental scale, while local climate dataset used for modelling species distribution enables conservationists to delineate reliable conservation areas in fragmented natural habitats at landscape scale.