Contrasting effects of prey refuge on biodiversity of species

Refugia have been perceived as a major role in structuring species biodiversity, and understanding the impacts of this force in a community assembly with prey–predator species is a difficult task because refuge process can interact with different ecological components and may show counterintuitive effects. To understand this problem, we used a simple two-species model incorporating a functional response inspired by a Holling type-II equation and a prey refuge mechanism that depends on prey and predator population densities (i.e., density-dependent prey refuge). We then perform the co-dimension one and co-dimension two bifurcation analysis to examine steady states and its stability, together with the bifurcation points as different parameters change. As the capacity of prey refuge is varied, there occur critical values i.e., saddle-node and supercritical Hopf bifurcations. The interaction between these two co-dimension one bifurcations engenders distinct outcomes of ecological system such as coexistence of species, bistability phenomena and oscillatory dynamics. Additionally, we construct a parameter space diagram illustrating the dynamics of species interactions as prey refuge intensity and predation pressure vary; as the two saddle-node move nearer to one another, these bifurcations annihilate tangentially in a co-dimension two cusp bifurcation. We also realised several contrasting observations of refuge process on species biodiversity: for instance, while it is believed that some refuge processes (e.g., constant proportion of prey refuge) would result in exclusion of predator species, our findings show that density-dependent prey refuge is beneficial for both predator and prey species, and consequently, promotes the maintenance of species biodiversity.

Characteristics of the Hole-Meadow Vegetation of Kur-Aras Lowland (Azerbaijan)

In article the description of the main types of meadow communities which were registered in Mil plain was given. It was also given their geobotanical classification. Distribution, contemporary situation, species biodiversity, morphobiological, bioecological and phytocenological features of this vegetation was analyzed. It was determined that hole-meadow vegetation type of researched area contains 4 formation classes, 14 formation groups and 39 associations.

Ozone Induces Distress Behaviors in Fig Wasps with a Reduced Chance of Recovery

Among anthropogenic environmental risks, air pollution has the potential to impact animal and plant physiology, as well as their interactions and the long-term survival of populations, which could threaten the functioning of ecosystems. What is especially alarming is that the concentration of tropospheric ozone (O3) has dramatically increased since pre-industrial times. However, the direct effects of O3 on the behavior of pollinators themselves have not been investigated so far even though insect behavior is key to their ecological interactions, which underpin the stability of ecological networks responsible for species biodiversity in ecosystems. In this study, we aim to determine the potential effects of O3 episodes at different field-realistic concentrations (0, 40, 80, 120, and 200 ppb for 60 min) on the behavior of the fig wasp Blastophaga psenes by monitoring exposed individuals hourly for 5 h after exposure. We found that ozone episodes induced major changes in insect behavior, which were already significant at 80 ppb with individuals displaying abnormal motility. The tracking over time clearly showed that exposed individuals might only have a reduced chance of recovery, with a decreasing proportion of active fig wasps despite the cessation of an O3 episode. These findings illustrate that O3 episodes can affect pollinator behavior, which may have detrimental implications for pollination systems. It is, therefore, of importance to assess the effects of O3 on insect behavior in order to predict how it could modify ecological interactions and species biodiversity in ecosystems.

Changes in the nocturnal activity of birds during the COVID–19 pandemic lockdown in a neotropical city

The COVID–19 lockdown provided the opportunity to measure species biodiversity in urban environments under conditions divergent from regular urban rhythms. For 90 days, including weeks of strict lockdown and the subsequent relaxation of restrictions, we measured the presence and abundance of birds that were active at night at two sites in the city of Cali, Colombia. Our results show that species richness of nocturnal birds decreased 40 % to 58 % during the weeks with more human activity, adding further evidence to the biodiversity responses of the ‘anthropause’ on urban environments.

Identifying key federal, state, and private lands strategies for achieving 30×30 in the US

Addressing the current biodiversity crisis will require transformative changes to social, political, and economic structures. One science-based recommendation is protecting 30% of the Earth’s terrestrial and marine systems by 2030, “30×30”. Here we analyze the current spatial patterns of imperiled species biodiversity and carbon stores in the U.S. relative to protected areas to help conservationists and decision makers understand the starting point on the path to achieving 30×30. Multi-scale analyses demonstrate that 30×30 is numerically achievable nationally, but high spatial heterogeneity highlights the need for tailored approaches from a mix of authorities at federal, regional, and state scales. Critically, current land protections rarely overlap with areas essential for conserving imperiled species biodiversity and mitigating climate change. We discuss this baseline relative to key policy considerations for making practical, substantive progress toward the goal.