Forest Structure and Anthropogenic Disturbances Regulate Plant Invasion in Urban Forests

Abstract

Urban forest ecosystems, the structure and functions therein, are subjected to anthropogenic disturbances. Native and sensitive species from those forests might be lost due to such disturbances. At the same time, supplemented anthropogenic resources might create opportunities for exotic and invasive species. Although, invasive species are considered as one of the major threats to the urban biodiversity and ecosystems, the researches on invasion dynamics in the Himalayas have mostly focused on the impacts of invasion on forest structure and productivity. This study aims to understand the influence of forest structure and anthropogenic factors in invasion success that are poorly covered in the existing literature. We selected 11 urban forest patches for the study considering the presence-absence of selected invasive species and structural attributes. We used Principal Component Analysis (PCA) to reduce co-linearity in the covariates and generalized linear mixed effects model (GLMM) to identify the factors affecting the invasion success. We found that the structural attributes of the forests and anthropogenic disturbances regulated invasion success in urban forests. This implies that maintaining urban forest structural attributes, especially maintaining the stands with large-sized trees, are essential to regulate and control invasion in the context of urbanization.

The Many Faces of Hemolysis

“…This structure describes antibodies IgA, IgD, IgE, and IgG. A monomer is composed of 2 light chains and 4 heavy chains that are made up of various amino acids 6. The amino acid sequence varies among the 4 antibody isotypes; this sequence determines the immune function of the antibody 5.…”

“…The amino acid sequence is the same for each arm and unique to a specific antigen. When activated, the Fc receptor in the leg is capable of binding a single complement molecule6,14 Abbreviation: Fc, fragment crystallizable.…”

“…The molecule has 10 binding sites for antigen and 5 for complement. The variable region has the same amino acid sequence on all 10 points, so only 1 type of antigen can affix to the molecule 6,14. Abbreviation: Fc, fragment crystallizable.…”

“…Five isotypes of these proteins have been recognized: IgA, IgD, IgE, IgG, and IgM 5. IgA has 2 subclasses (IgA 1 and IgA 2 ) and IgG has 4 subclasses (IgG 1 , IgG 2 , IgG 3 , and IgG 4 ) 5,6. Antibody production is synthesized by the immune system, specifically plasma cells and B cells.…”

“…Each of the 5 antibody isotypes has a distinct function in the immune system (eg, phagocytosis, allergen). When an antibody is synthesized, it is in response to a specific antigenic stimulation; all clones of the antibody will react only to that 1 antigen 6. Research has shown that the human body is capable of making at least 1 trillion unique antibodies, and that number is probably closer to 1 quintillion (1 million trillion) 7,8…”