Pathogens as agents of diversity in forested landscapes

It is argued that native forest pathogens may be viewed as major agents of spatial and temporal diversity, responsible for the creation of a number of special habitats, and influencing the speed and direction of succession as well as the structure of the climax forest. Although their influence is detrimental to most common purposes of management, the result of their action may occasionally be beneficial.

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Native forest pathogens facilitate persistence of Douglas-fir in old-growth forests of northwestern California

Canadian Journal of Forest Research ◽

10.1139/x11-053 ◽

2011 ◽

Vol 41 (6) ◽

pp. 1256-1266 ◽

Cited By ~ 6

Author(s):

Ashley E. Hawkins ◽

Terry W. Henkel

Keyword(s):

Bark Beetles ◽

Tree Mortality ◽

Douglas Fir ◽

Native Forest ◽

Gap Formation ◽

Old Growth ◽

Forest Pathogens ◽

Canopy Trees ◽

White Fir ◽

Closed Canopy

Forest pathogens and insects can accelerate tree mortality, increase stand structural heterogeneity, and alter tree community composition. In northern California, the canopy trees Abies concolor var. lowiana (Gord. & Glend.) Lemmon (white fir) and Pseudotsuga menziesii var. menziesii (Mirbel) Franco (Douglas-fir) co-occur but vary in shade tolerance and regenerative abilities following disturbance. Field observations suggested that mortality and turnover of white fir exceeded that of Douglas-fir and that native pathogens may be important drivers in the absence of fire. Pathogens and bark beetles were sampled in old-growth white fir – Douglas-fir stands in northwestern California to assess their contribution to tree mortality, gap formation, and regeneration. We determined abundances and size class distributions of canopy trees, presence of pathogens and bark beetles, and causes of tree mortality. We sampled canopy gaps and closed-canopy forests for overstory species composition, cause of mortality of gap-maker trees, and regeneration of white fir and Douglas-fir. Root-rot fungi accounted for significantly higher mortality and gap formation in white fir than in Douglas-fir. Relative seedling–sapling density of Douglas-fir was higher in pathogen-induced canopy gaps than in closed-canopy forest. In the absence of fire, native forest pathogens enable regeneration and persistence of Douglas-fir by enhancing mortality of white fir, resulting in canopy gap formation.

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Litterfall production and fluvial export in headwater catchments of the southern Amazon

Journal of Tropical Ecology ◽

10.1017/s0266467406003956 ◽

2007 ◽

Vol 23 (3) ◽

pp. 329-335 ◽

Cited By ~ 25

Author(s):

Evandro Carlos Selva ◽

Eduardo Guimarães Couto ◽

Mark S. Johnson ◽

Johannes Lehmann

Keyword(s):

Rainy Season ◽

Riparian Zone ◽

Stream Water ◽

Dry Season ◽

Native Forest ◽

Lateral Movement ◽

Mato Grosso ◽

Litterfall Production ◽

Forested Landscapes ◽

Southern Amazonia

Resolving the carbon (C) balance in the Amazonian forest depends on an improved quantification of production and losses of particulate C from forested landscapes via stream export. The main goal of this work was to quantify litterfall, the lateral movement of litter, and the export of coarse organic particulate matter (>2 mm) in four small watersheds (1–2 ha) under native forest in southern Amazonia near Juruena, Mato Grosso, Brazil (10°25′S, 58°46′W). Mean litterfall production was 11.8 Mg ha−1 y−1 (5.7 Mg C ha−1 y−1). Litterfall showed strong seasonality, with the highest deposition in the driest months of the year. About two times more C per month was deposited on the forest floor during the 6-mo dry season (0.65 Mg C ha−1 mo−1) compared with the rainy season (0.3 Mg C ha−1 mo−1). The measured C concentration of the litterfall samples was significantly greater in the dry season than in the rainy season (49% vs. 46%). The lateral movement of litter increased from the plateau (upper landscape position) towards the riparian zone. However, the trend in C concentration of laterally transported litter samples was the opposite, being highest on the plateau (44%) and lowest in the riparian zone (42%). Stream-water exports of particulate C were positively correlated with streamflow, increasing in the rainiest months. The export of particulate C in streamflow was found to be very small (less than 1%) in relation to the amount of litterfall produced.

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Effectiveness of Arguments Used in the Creation of Protected Areas of Sustainable Use in Brazil: A Case Study from the Atlantic Forest and Cerrado

Sustainability ◽

10.3390/su11061700 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1700 ◽

Cited By ~ 4

Author(s):

Mariane Roque ◽

José Ferreira Neto ◽

André Faria ◽

Fernanda Ferreira ◽

Thais Teixeira ◽

...

Keyword(s):

Land Use ◽

Protected Areas ◽

Atlantic Forest ◽

Conservation Status ◽

Sustainable Use ◽

Bare Soil ◽

Native Forest ◽

Empirical Reality ◽

The Creation

Studies on the effectiveness of the discourse motivating the creation of protected areas (PAs) and their empirical reality are scarce. The lack of knowledge in this area affects programs and policies on the maintenance and creation of protected areas. Thus, we investigated this matter using the case study of the Nascente Geraizeiras Sustainable Development Reserve (NGSDR) in Minas Gerais State, Brazil. The reserve comprises a transition area between Cerrado and the Atlantic Forest, two critical biomes in the world of biodiversity and the only two hotspots in Brazil. Changes in land use were identified over a period of 30 years, from 1987 to 2017, based on a compilation of the arguments associated with the creation of the PA, geographic information system (GIS) techniques, remote sensing (RS) data, and landscape ecology indices. Seven types of land use were identified using Random Forest classifier R software: native forest, silviculture, pasture, bare soil, rocky outcrop, watercourses, and agriculture. The overall mean accuracy of the classification was 90% for all five periods. The results demonstrated that the creation of protected areas is supported by contexts of land use still based on traditional. The case study showed the discourse served as a fundamental strategy in the beginning of the mobilization that culminated in the creation of the NGSDR, in the containment of forestry, in an increase in native forest areas, and in reduced fragmentation, leading to an improvement in the conservation status of the landscape. The present study encourages future researchers to apply the evaluated approach and demonstrates its potential in assessing the formulation of programs and policies on protected areas worldwide, providing valid indicators for the improvement of ecosystem services.

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The role of affect in feelings of obligation

Behavioral and Brain Sciences ◽

10.1017/s0140525x19002449 ◽

2020 ◽

Vol 43 ◽

Author(s):

Stefen Beeler-Duden ◽

Meltem Yucel ◽

Amrisha Vaish

Keyword(s):

Positive Emotions ◽

The Creation ◽

Sense Of Obligation

Abstract Tomasello offers a compelling account of the emergence of humans’ sense of obligation. We suggest that more needs to be said about the role of affect in the creation of obligations. We also argue that positive emotions such as gratitude evolved to encourage individuals to fulfill cooperative obligations without the negative quality that Tomasello proposes is inherent in obligations.

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