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Understanding the relationships between below- and aboveground plant community diversity and composition is essential for understanding plant-soil linkages and feedbacks. Here we examine the patterns of belowground plant species richness, evenness, community composition, and individual species relative abundance with soil depth in a rough fescue grassland. Plant taxa belowground were identified via next-generation sequencing of the trnL intron. We found weak positive below-aboveground concordance in plant species composition demonstrating a general similarity between aboveground and belowground communities. The positive relationship between below- and aboveground plant species richness was stronger within the A horizon than in the B horizon, indicating that some species avoided rootingmore deeply in the soil. For the most common graminoid species at the site, there was no evidence for depth-related rooting preferences for species of Carex (sedges) or Elymus (wheatgrasses), while the dominant native grass Festuca hallii preferentially rooted shallowly while the invasive grass Bromus inermis rooted more deeply. Differential rooting patterns among some of the dominant species suggests some degree of belowground niche differentiation may be important in structuring this plant community.
The North American beaver is considered a keystone species because its behaviour leads to profound changes in the wetland systems within forested landscapes. Such changes influence species composition and their interactions. However, in some cases, beavers are considered as an important source of disturbance and conflict with anthropogenic activities. In this paper, we reviewed regional studies using geomorphology, food availability and anthropogenic infrastructure on spatial modelling of beaver habitat. Even though all studies used different sets of variables and methodologies, important factors affecting beaver occurrence or abundance are mainly stream gradient, watershed size and hardwood cover that is adjacent to the streams. However, the identification of key habitat indicators often varies between studies depending upon the object being modelled (colonies vs. dams), the geomorphological characteristics of the region, and the scale of the study area. Recent developments in geomatics and improved data quality now allow spatial modelling of beaver habitat across larger areas, and make models using at least stream gradient and forest cover types more accessible to managers. Such large-scale predictive beaver habitat models could have valuable applications for the prevention of infrastructure damage and related costs, and for managing wildlife species that rely upon beaver ponds.
Rocket launches are a source of anthropogenic disturbance to Central Kazakhstan ecosystems. Multistage launch vehicles (LV) are used for orbit insertion of different spacecrafts from the Baikonur cosmodrome (Republic of Kazakhstan). The launch consists of stages during which the rocket separates successively, with pieces falling to the ground along the flight route of the LV. Regions of first stage falling located in Central Kazakhstan endure the most intensive impact. First stage fallings lead to mechanical and pyrogenic disturbance and pollution by fuel components. We characterized vegetation changes at the first stage falling sites of ‘Proton-M’ rocket carriers during two growing seasons. Spontaneous revegetation by ruderal plant communities occurs after falling. First stage falling sites have lower vegetation cover and species diversity. Ceratocarpus arenarius is a dominant species in plant communities at the sites that have been affected by first stage falling. After winter rocket launches vegetation is less deteriorated at the falling sites than after spring and summer launches. The recovery process in plant communities is considerably faster at falling sites corresponding to winter rocket launches.
In boreal peatlands, low decomposition rate is the underlying cause of carbon sequestration. Decomposition of litter can be affected by factors relating to soil moisture and temperature, the quality of the litter, and by the biotic decomposer community, among others. Exploring how these drivers interact will provide better understanding of carbon dynamics in boreal peatlands. We measured the decomposition of three common peatland plant functional types (moss, sedge, shrub), and associated microarthropod communities using litterbags placed in hollows (wet depressions) and hummocks (dry, raised areas) of a boreal peatland in Ontario, Canada. Decomposition was significantly different between all plant litter types, and greatest in sedge, but was not significantly different between hummock and hollow microhabitats. The decomposer community displayed an opposite pattern, significantly affected by microhabitat where richness and abundance of microarthropods was greater in hollows than hummocks. Oribatid mites were the dominant microarthropod with respect to both richness and abundance. Plant litter type did not affect community structure in hollows, but was a determinant of oribatid dominance in hummocks. These results suggest that abiotic environmental conditions are the main drivers of community structure for decomposers, while plant litter quality is a more important determinant of decomposition dynamics in boreal peatlands.
Disturbances can affect the biotic resistance of plant communities and alterations could take place in the system, such as the appearance or increase in abundance of new components. To characterize the resistance to disturbance and the aptitude to limit the establishment of alien plants, it is necessary to know the functional and specific diversity of plant communities. The objective was to evaluate the effects of grazing by feral horses on the resistance of natural grasslands of Argentina to alien plant invasion by means of specific composition and functional structure. Two grasslands under continuous grazing by feral horses and two exclosures were studied. Species composition and functional structure were characterized using species richness, Shannon's diversity index, functional richness, functional evenness and functional divergence. Alien plant richness and abundance, as well as alien:native plants ratio were determined. Specific composition and functional structure were negatively affected by feral horse grazing and the distribution of alien species in the different functional groups differed in areas with contrasting grazing histories. The activity of feral horses can modify the abundance of dominant plants and functional diversity, thus providing niche opportunities for the establishment of alien plants, in turn affecting the function and structure of the system.
Since 1974, conservation efforts to protect an endangered species, the Golden Lion Tamarin (GLT), have led to the creation of the first strict nature reserve in Brazil ‒ the Poço das Antas Biological Reserve (REBIO) ‒ and the subsequent creation of the Environmental Protection Area of the Sao Joao River Basin, for sustainable use. This paper assesses the influence of Protected Areas (PA) creation and conservation programs on GLT habitat. Landscape metrics based on aerial photographs taken from three different periods are used to assess habitat conditions for this species through time. We analyzed the availability and potential quality of habitat in the years following the creation of the REBIO, comparing with its buffer zone and population rates correlations. We observed different trends in landscape dynamics between the REBIO, where most of the forest recovery occurred, and its buffer zone, where habitat loss was recorded. In general, the results showed an increase of continuous forest patches. The conservation/regeneration processes in the buffer zone have intensified in recent years. Comparisons over time, especially with respect to forest core areas and large patches, are valuable tools to assess landscape suitability for GLT survival at different spatial scales.
In birds, long-term pairing often comes with increased breeding success, but also with strong and intricate relationships associated with social benefits, resulting in a lower likelihood of divorce. However, a relationship may wither and the temptation of new partnership opportunities can lead to divorces and re-pairing, especially in social species, like rooks, who live all year round in colonies. Here, we scrutinized the behavioural patterns leading to divorce and pair formation by adulthood in a group of captive rooks. Divorces were concomitant to the formation of new pairs, with one or both separating partners gradually switching to another relationship. Individuals switching from one pair to another were socially less active than their non-switching partner (the old and new). Once established, newly formed pairs were immediately as strong as older stable pairs. Separating pairs were characterized by high rates of agonistic behaviours. Food sharing played a role in the formation of new pairs, while sexual behaviours did not. We showed that adult rooks do not necessarily pair for life, and have the ability to strongly re-bond with another partner. This emphasizes the social flexibility of this cognitively advanced species, and sheds new light on mate choice strategies in long-term monogamous species.
KEYWORDS: fish assemblages, macroinvertebrates, tropical Andes, environmental quality indices, Neotropical stream, protected area, assemblages de poissons, macro-invertébrés, Andes tropicales, indices de qualité de l'environnement, cours d'eau néotropical, aire protégée
Knowledge of the fish assemblages of Andean mountain streams is restricted to accessible areas. This study is the first biological survey of the remote Suaza River in the Colombian Andes, at its source in the Cueva de los Guácharos National Park. Mechanistic insight into the ecological patterns and gradients of the river is provided, focusing on the spatial distribution of fish communities in relation to environmental variables and habitat characteristics. Electrofishing surveys and macroinvertebrate sampling were carried out, the river habitat was characterized, three environmental quality indices were applied, and potential water pollutant concentrations were measured. Twenty-seven fish species were recorded — two of them exotic (Poecilia reticulata and Xiphophorus hellerii) — as well as 45 macroinvertebrate families. Fish species richness was higher at lower altitudes with gentle slopes, where habitat temperature, size and heterogeneity were higher. Although macroinvertebrate diversity slightly increased downstream following a similar pattern as fish species richness, it declined at lower sites. Fish assemblages were distributed in three clusters corresponding to headwaters, middle sections and lower reaches of the river, showing correlations with environmental factors, suggesting habitat preferences. Although the headwaters of the Suaza River remains pristine inside the park, human influence is responsible for ecosystem alteration downstream.
Tropical cloud forests are under severe distress, as deforestation leads to forest fragmentation and degradation. This represents a severe threat to small-ranged, forest-dependent species, as they are at risk of losing habitat and connectivity between populations. These detrimental effects are aggravated by upslope range shifts caused by climate change, as further habitat loss is expected. To mitigate these threats, the preservation of habitat and connectivity becomes necessary. Here, we present a novel framework for identifying future key areas offering highquality habitat and connectivity. The framework combines data on the composition of forests, their configuration in the landscape, as well as dispersal abilities and altitudinal range for several focal species. Importantly, the framework integrates projections of future range shifts. Thus, it prioritizes a network of areas with high-conservation value robust to climate change. We applied the framework to the cloud forest in Ecuador, using two endemic bird species to identify areas for mitigating the adverse effects of climate change. Our approach allows targeting reforestation measures effectively to areas of high-conservation value. The framework presented here can be applied to different ecosystems and geographical locations, and therefore contribute to making informed decisions about the implementation of robust conservation measures.
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