Intermediate levels of wood extraction may facilitate coexistence of an endemic arboreal marsupial and Indigenous communities

Land-use change is a major driver of biodiversity loss. Large-scale disturbances such as habitat loss, fragmentation and degradation are known to have negative consequences for native biota, but the effects of small-scale disturbances such as selective logging are less well known. We compared three sites with different regimes of selective logging performed by Indigenous communities in the South American temperate rainforest, to assess effects on the density and habitat selection patterns of the Near Threatened endemic arboreal marsupial Dromiciops gliroides. We used structured interviews to identify patterns of wood extraction, which was 0.22–2.55 m3 per ha per year. In the less disturbed site only two tree species were logged, in the intermediately disturbed sites eight species were logged at low intensity, and in the most disturbed site seven species were logged intensively. The site with intermediate disturbance had the highest fleshy-fruited plant diversity and fruit biomass values as a result of the proliferation of shade-intolerant plants. This site also had the highest density of D. gliroides. These findings are consistent with Connell's intermediate disturbance hypothesis, suggesting that coexistence of people with nature is possible if wood extraction volumes are moderate, increasing plant diversity. Indigenous communities have sustainably used natural resources for centuries, but current rates of land-use change are becoming a significant threat to both them and their natural resources.

Intermediate ice scour disturbance is key to maintaining a peak in biodiversity within the shallows of the Western Antarctic Peninsula

Climate-related disturbance regimes are changing rapidly with profound consequences for ecosystems. Disturbance is often perceived as detrimental to biodiversity; however, the literature is divided on how they influence each other. Disturbance events in nature are diverse, occurring across numerous interacting trophic levels and multiple spatial and temporal scales, leading to divergence between empirical and theoretical studies. The shallow Antarctic seafloor has one of the largest disturbance gradients on earth, due to iceberg scouring. Scour rates are changing rapidly along the Western Antarctic Peninsula because of climate change and with further changes predicted, the Antarctic benthos will likely undergo dramatic shifts in diversity. We investigated benthic macro and megafaunal richness across 10–100 m depth range, much of which, 40–100 m, has rarely been sampled. Macro and megafauna species richness peaked at 50–60 m depth, a depth dominated by a diverse range of sessile suspension feeders, with an intermediate level of iceberg disturbance. Our results show that a broad range of disturbance values are required to detect the predicted peak in biodiversity that is consistent with the Intermediate Disturbance Hypothesis, suggesting ice scour is key to maintaining high biodiversity in Antarctica’s shallows.

A historic geographic approach to the anthropic disturbance in the Bükk region

This paper introduce a historical geographical study on the process of land cover transformation in the Bükk Region, which can be regarded as a two-faced area concerning its anthropogenic disturbance. Based on historic mapping that began as early as the late 18th century, a database was produced, and the data was interpreted in the context of economic and social processes that took place in the area. Results could be presented in maps using the so-called Anthropogenic Disturbance Index (ADI). These maps demonstrate the peculiar land use pattern in the Bükk Region, namely co-habitation of the significantly transformed margins and the natural or quasi-natural central part. Between them, there are linear areas of intermediate disturbance. These areas, however, due to the foundation and activity of the Bükk National Park and modification of their economic value after the change of the political system, have not increased during the last several decades; rather a re-naturalization of the landscape is aimed.

Investigating Ecological Disturbance in Streams

Teaching students about ecological disturbance provides them with an understanding of a critical factor that shapes the structure and function of biological communities in environmental systems. This article describes four simple experiments and related curriculum that students can use to conduct inquiry around the theme of disturbance in stream ecosystems: insect drift, colonization, life history, and the intermediate disturbance hypothesis. Over five years, our students conducted these experiments 57 times; 79% of the experiments resulted in data that supported students’ hypotheses. Our findings show that the experiments can be used as a framework for inquiry-based learning about important ecological processes such as disturbance, dispersal, colonization, and succession. These experiments meet several of the Next Generation Science Standards, are easily and ethically conducted, and require very little equipment.

Impacts of soil disturbance on plant diversity in a dry grassland

Dry grasslands are among the most species rich habitats in Europe, but they are also among the most threatened. Threats include too high and too low levels of disturbance. The aim of this study is to examine the effect of soil disturbance intensity on species composition and diversity in a dry grassland in Mols Bjerge National Park in Denmark. We recorded vascular plant species inside and just outside patches of bare sand, and in the transition zone between these. We found that the number of species was highest in the dense vegetation, intermediate at the transition and lowest in bare sand areas. However, an analysis of plant traits showed that the number of small annual species was highest in the transition zone. High abundance of small annual species may therefore indicate intermediate disturbance regimes. Based on a literature study we demonstrate that many threatened species are adapted to such habitats. This suggests that dry grasslands should be managed to maintain areas with intermediate disturbances intensities to maintain optimal conditions for many threatened species. To our knowledge, this is the first time it has been documented that small annual species can indicate intermediate disturbance regimes in dry grasslands.

Grime's CSR Strategies of Aquatic Macrophytes in Different Lagoon Lakes in Northern Turkey

In this study, CSR strategies, biological diversity and water traits were evaluated in three lagoon lakes (Liman, Cernek and Balık) which had different nutrient status in the Central Black Sea Region of Turkey. The most productive lake was Balık lake, while the lowest productive lake is Liman lake in the study area. Secondary strategies were found to be dominant in studied lakes. No species exhibit pure S-strategy in the present study. pH, electrical conductivity, P and NH4 concentrations were found to be significant. However, total of nitrite-N and nitrate-N concentrations were not significant. EC and pH were associated with the species in Liman and Cernek lakes, respectively. However, P and NH4 concentrations were associated with the species in Balık lake according to canonical correspondence analysis. Significant correlations were found among chemical traits and biological diversity. pH was positively correlated with Shannon-Wiener index, while negatively correlated with Simpson and Berger-Parker indexes. No significant correlations were found between water P concentrations and evenness. Our data supported intermediate disturbance hypothesis in the studied lakes.

Diferentes distúrbios antrópicos na paisagem podem influenciar padrões florísticos e estruturais da Mata Atlântica?

This study aimed to describe and compare the floristic and structural component of the tree component, as well as the alpha and beta diversity, as well as the floristic similarity of a remnant of Semideciduous Forest. The tree vegetation was sampled at two edges in contact with pasture (BP) and coffee growing (BC), and inside the fragment (INT). 2.840 individuals were sampled, identified in 56 families, 144 genera and 271 species (94 BC, 128 BP and 178 INT). The border stretches were characterized by higher density and smaller basal area than the interior, indicating the occurrence of disturbances. The variations in the structural floristic composition of the tree communities wereinfluenced by regional and local environmental variations, as well as the historical use of the area, according to Niche and Intermediate Disturbance Theories.

Activity density of carabid beetles along an urbanisation gradient

Several works have investigated the impact of urbanisation on carabid activity density using urban-rural gradients. Such works compared activity density recorded from green spaces located in different parts of a city and assigned to categories of increasing urban intensity, which poses two problems: (1) since the gradient is divided into categories, it is impossible to model continuous variations in biotic responses, and (2) sites representative of different urbanisation levels are not true segments of the same ecological continuum. To surpass these problems, we modelled variations in carabid activity density along an urban-rural transect within a single green space extending from the city centre of Rome to rural environments. Carabids were sampled by pitfall traps from sites distributed along the entire gradient. We used breakpoint regressions to model how (1) carabid activity density, (2) carabids/beetles ratio, (3) carabids/insects ratio and (3) carabids/arthropods ratio varied along the gradient. As already observed for various organisms in urban environments, we found that activity density of carabids and their contribution to the abundance of beetles, insects and arthropods, peaked in the middle of the gradient. This supports the intermediate disturbance hypothesis, according to which moderate urbanisation may favour diversity by increasing habitat heterogeneity.