Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

:The carbon sink capacity of the world’s agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossilfuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.

/pdf/soil-carbon-sequestration-impacts-on-global-climate-change-1w7459lbbk.pdf

Soil carbon sequestration impacts on global climate change and food security.

Interactions between organisms are a major determinant of the distribution and abundance of species. Ecology textbooks (e.g., Ricklefs 1984, Krebs 1985, Begon et al. 1990) summarise these important interactions as intra- and interspecific competition for abiotic and biotic resources, predation, parasitism and mutualism. Conspicuously lacking from the list of key processes in most text books is the role that many organisms play in the creation, modification and maintenance of habitats. These activities do not involve direct trophic interactions between species, but they are nevertheless important and common. The ecological literature is rich in examples of habitat modification by organisms, some of which have been extensively studied (e.g. Thayer 1979, Naiman et al. 1988).

Organisms as ecosystem engineers

Indigenous groups offer alternative knowledge and perspectives based on their own locally developed practices of resource use. We surveyed the international literature to focus on the role of Traditional Ecological Knowledge in monitoring, responding to, and managing ecosystem processes and functions, with special attention to ecological resilience. Case studies revealed that there exists a diversity of local or traditional practices for ecosystem management. These include multiple species management, resource rotation, succession management, landscape patchiness management, and other ways of responding to and managing pulses and ecological surprises. Social mechanisms behind these traditional practices include a number of adaptations for the generation, accumulation, and transmission of knowledge; the use of local institutions to provide leaders/stewards and rules for social regulation; mechanisms for cultural internalization of traditional practices; and the development of appropriate world views and cultural values. Some traditional knowledge and management systems were characterized by the use of local ecological knowledge to interpret and respond to feedbacks from the environment to guide the direction of resource management. These traditional systems had certain similarities to adaptive management with its emphasis on feedback learning, and its treatment of uncertainty and unpredictability intrinsic to all ecosystems.

http://wildrodopi.org/data/documents/Rediscovery-Traditional-Ecological=20Knowledge.pdf

Rediscovery of traditional ecological knowledge as adaptive management

Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local high-intensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2005.00782.x

Landscape perspectives on agricultural intensification and biodiversity – ecosystem service management

Structural parameters of mangrove forests were measured at seven geographical locations in Florida (U.S.A.), Puerto Rico, Mexico, and Costa Rica. One-tenth hectare plots were subdivided into twenty 5 x 10 m plots where all individuals greater than 2.5 cm DBH were measured and recorded. Height of the tallest tree in each plot was measured. The complexity index developed by Holdridge (1967) as an integrative measure that combines floral characteristics (number of species) (s), stand density (d), basal area (b), and height (h) was computed as follows: (s) (d) (b) (h) 10-3. The riverine and basin mangrove forests of the southwestern coast of Florida had considerably taller trees (6-9 m) and larger basal areas (20.3-38.5 m2/ha) than did scrub mangrove growing on the southeastern Coast of Florida where a low canopy (1.0 m), a low basal area (6.0 m2/ha), and a correspondingly low complexity index (1.5) were measured. The riverine forests of the Marismas Nacionales located on the Pacific coast of Mexico had high complexity indices (49.7-73.2) due to the large basal areas (57.8-60.8 m2/ha), tall canopies (16-17 m) and a large number of trees greater than 10 cm diameter (103-145/ha). The entire estuarine system of the Marismas Nacionales acts as a receiving basin for large quantities of freshwater runoff and nutrient-rich sediments from surrounding upland watersheds. Except for local sport fishing, the commercial fishing industry of Florida, Puerto Rico, and Costa Rican mangrove waters is not nearly as active as that observed near Teacap'an, Mexico. The structural characteristics of the north- and south-coast mangroves of Puerto Rico are probably best described by the direct and indirect influences of the climate at each coastline. The basin mangrove forest on the humid north coast (annual rainfall of 1631 mm) has a basal area of 17.8 m2/ha, canopy height of 13.6 m, and a complexity index of 16.7. The driest site (rainfall of 860 mm/year) on the south coast of Puerto Rico was a red mangrove fringe forest which had a complexity index of 0.9, low canopy height (7 m), and low basal area (6.9 m2/ha). Here upland runoff, draining into the mangroves through porous limestone outcrops, only occurs 1-2 months annually. In Costa Rica, the riverine mangroves near Puerto Limon on the Caribbean coast (annual rainfall- of 3306 mm) are more structurally developed than either the riverine or fringe mangroves of the drier (1800 mm annual rainfall) Pacific coast sites. A basal area of 96.4 m2/ha (primarily Pterocarpus officinalis Jacq.) and a tall canopy (16 m) gave this forest the largest complexity index (84.5) of all forests inventoried. The Pacific coast mangroves of Costa Rica are exposed to seasonal rainfall (six months dry season), and this drier environment was reflected in a shorter canopy (9.510.0 m) and a lower basal area (23.2-32.9 m2/ha).

Structure of Mangrove Forests in Florida, Puerto Rico, Mexico, and Costa Rica

Introduction Holdridge (1947, 1967) developed a bioclimatic classification system by which the world's terrestrial biota may be categorized into approximately 120 life zones, each distinguished by climatic parameters that coincide with particular vegetational characteristics. Approximately 68 life zones are in the tropics and subtropics, of which 30 are dominated by forest of various types. Lugo, Schmidt & Brown (1981) estimated that 28 tropical and subtropical forested life zones are represented in Central America and the Caribbean, and 13 are found on the islands of the Caribbean. Despite this diversity, approximately half of the vegetation of Central America and the Caribbean is within the dry forest life zone (sensu Holdridge, 1967). Dry forests are not infrequently referred to as deciduous forests, but the degree of deciduousness varies greatly (see below). Not all dry forests are conspicuously deciduous, and not all deciduous forests are dry forest. By Holdridge's criteria, tropical and subtropical dry forests are found in frost-free areas where mean annual biotemperature (a special calculation that reduces the effects of extreme temperatures) is above 17 °C, annual rainfall ranges from 250 to 2000 mm, and the ratio of potential evapotranspiration to precipitation is greater than one, to a maximum value of two. By these criteria, 49% (8.2 × 10 5 km 2 ) of the vegetation of Central America and the Caribbean is considered dry forest (Brown & Lugo, 1980). Africa has the most dry forest (16.5 × 10 6 km 2 ; 73% of the continent's vegetation); worldwide, about 42% of all intratropical vegetation is dry forest. Global patterns in dry forest distribution and overall ecological characteristics relative to wetter tropical and subtropical forest ecosystems were reviewed by Murphy & Lugo (1986a).

Seasonally Dry Tropical Forests: Dry forests of Central America and the Caribbean

Twenty-eight worldwide reports of massive mangrove tree mortalities are reviewed. Massive mortality is defined as tree mortalities that occur in response to rapid environmental change and affect all size dasses. Massive mortality occurs in addition to normal tree mortality. Normal tree mortality was described using structural data from 114 mangrove stands. This mortality is density dependent, follows orderly time dependent patterns dictated by stand maturation (related to average tree diameter), and usually occurs in the smaller diameter size classes. Disease and other biotic factors do not appear to be primary causes of massive mangrove mortalities. Instead, these factors appear to attack forests weakened by changes in the physical environment. Mangrove environments are dynamic and cyclical and mangrove associations adapt to such environments by both growing and dying fast. Mangrove species' characteristics such as the capacity to produce large quantities of propagules that take advantage of dispersal agents, sharp species zonations, and even-aged populations contribute to the rapid growth-mortality cycles in mangroves. Humans may tilt the balance towards higher mortality rates by introducing chronic stressors that inhibit regeneration mechanisms. MANGROVE FORESTS ARE DYNAMIC ECOSYSTEMS. Factors such as sedimentation rates, soil subsidence, freshwater run-off, tidal forces, and changes in sea level influence mangrove growth and survival. In response, mangrove species arrange themselves in zones that reflect geomorphologic and hydrologic gradients (Lugo 1980). Consequently, significant changes in environmental conditions are generally followed by alterations in the vigor or zonation of vegetation. These alterations may include widespread tree mortality.

Tree Mortality in Mangrove Forests

Invasive alien tree species in Puerto Rico often form monospecific stands on deforested lands that were previously used for agriculture and then abandoned. Most native pioneer species are incapable of colonizing these sites, and thus introduced species have little competition from native trees. Alien trees may dominate sites for 30 to 40 years, but by that time native species begin to appear in the understory. By 60 to 80 years, unique communities comprising both alien and native species are found on these sites. This phenomenon is a response to a change in the disturbance regime of Puerto Rico's landscape, brought about by intensive agricultural land use and abandonment. The invasion of a site and the formation of an alien-dominated forest serve important ecological functions, such as repairing soil structure and fertility, and restoring forest cover and biodiversity at degraded sites.

https://www.fs.fed.us/global/iitf/pubs/ja_iitf_2004_lugo004.pdf

The outcome of alien tree invasions in Puerto Rico

Summary
Aim Our main goals were to develop a map of the life zones for the conterminous United States, based on the Holdridge Life Zone system, as a tool for ecosystem mapping, and to compare the map of Holdridge life zones with other global vegetation classification and mapping efforts.

Location The area of interest is the forty-eight contiguous states of the United States.

Methods We wrote a PERL program for determining life zones from climatic data and linked it to the image processing workbench (IPW). The inputs were annual precipitation (Pann), biotemperature (Tbio), sea-level biotemperature (T0bio), and the frost line. The spatial resolution chosen for this study (2.5 arc-minute for classification, 4-km for mapping) was driven by the availability of current state-of-the-art, accurate and reliable precipitation data. We used the Precipitation-elevation Regressions on Independent Slopes Model, or PRISM, output for the contiguous United States downloaded from the Internet. The accepted standard data for air temperature surfaces were obtained from the Vegetation/Ecosystem Modelling and Analysis Project (VEMAP). This data set along with station data obtained from the National Climatic Data Center for the US, were used to develop all temperature surfaces at the same resolution as the Pann.

Results The US contains thirty-eight life zones (34% of the world's life zones and 85% of the temperate ones) including one boreal, twelve cool temperate, twenty warm temperate, four subtropical, and one tropical. Seventy-four percent of the US falls in the ‘basal belt’, 18% is montane, 8% is subalpine, 1% is alpine, and < 0.1% is nival. The US ranges from superarid to superhumid, and the humid province is the largest (45% of the US). The most extensive life zone is the warm temperate moist forest, which covers 23% of the country. We compared the Holdridge life zone map with output from the BIOME model, Bailey's ecoregions, Kuchler potential vegetation, and land cover, all aggregated to four cover classes. Despite differences in the goals and methods for all these classification systems, there was a very good to excellent agreement among them for forests but poor for grasslands, shrublands, and nonvegetated lands.

Main conclusions We consider the life zone approach to have many strengths for ecosystem mapping because it is based on climatic driving factors of ecosystem processes and recognizes ecophysiological responses of plants; it is hierarchical and allows for the use of other mapping criteria at the association and successional levels of analysis; it can be expanded or contracted without losing functional continuity among levels of ecological complexity; it is a relatively simple system based on few empirical data; and it uses objective mapping criteria.

https://www.fs.fed.us/global/iitf/pubs/ja_iitf_1999_lugo002.pdf

Ariel E. Lugo

Papers

Structure of Mangrove Forests in Florida, Puerto Rico, Mexico, and Costa Rica

Seasonally Dry Tropical Forests: Dry forests of Central America and the Caribbean

Tree Mortality in Mangrove Forests

The outcome of alien tree invasions in Puerto Rico

The Holdridge life zones of the conterminous United States in relation to ecosystem mapping