What determines the number and size of the seeds produced by a plant? How often should it reproduce them? How often should a plant produce them? Why and how are seeds dispersed, and what are the implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment, and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function.

The ecology of seeds

Vertebrate responses to hunting are widely variable for target and nontarget species depending on the history of hunting and productivity of any given site and the life history traits of game species. We provide a comprehensive meta-analysis of changes in population density or other abundance estimates for 30 mid-sized to large mammal, bird and reptile species in 101 hunted and nonhunted, but otherwise undisturbed, Neotropical forest sites. The data set was analyzed using both an unnested approach, based on population density estimates, and a nested approach in which pairwise comparisons of abundance metrics were restricted to geographic groups of sites sharing similar habitat and soil conditions. This resulted in 25 geographic clusters of sites within which 1811 population abundance estimates were compared across different levels of hunting pressure. Average nested changes in abundance across increasingly greater levels of hunting pressure ranged from moderately positive to highly negative. Populations of all species combined declined across greater differences in hunting pressure by up to 74.8 percent from their numeric abundance in less intensively hunted sites, but harvest-sensitive species faired far worse. Of the 30 species examined, 22 declined significantly at high levels of hunting. Body size significantly affected the direction and magnitude of abundance changes, with large-bodied species declining faster in overhunted sites. Frugivorous species showed more marked declines in abundance in heavily hunted sites than seed predators and browsers, regardless of the effects of body size. The implications of hunting for seed dispersal are discussed in terms of community dynamics in semi-defaunated tropical forests.

Basin‐Wide Effects of Game Harvest on Vertebrate Population Densities in Amazonian Forests: Implications for Animal‐Mediated Seed Dispersal

As the terrestrial human footprint continues to expand, the amount of native forest that is free from significant damaging human activities is in precipitous decline. There is emerging evidence that the remaining intact forest supports an exceptional confluence of globally significant environmental values relative to degraded forests, including imperilled biodiversity, carbon sequestration and storage, water provision, indigenous culture and the maintenance of human health. Here we argue that maintaining and, where possible, restoring the integrity of dwindling intact forests is an urgent priority for current global efforts to halt the ongoing biodiversity crisis, slow rapid climate change and achieve sustainability goals. Retaining the integrity of intact forest ecosystems should be a central component of proactive global and national environmental strategies, alongside current efforts aimed at halting deforestation and promoting reforestation.

/pdf/the-exceptional-value-of-intact-forest-ecosystems-5gdyvuos4g.pdf

The exceptional value of intact forest ecosystems

Soils are subject to varying degrees of direct or indirect human disturbance, constituting a major global change driver. Factoring out natural from direct and indirect human influence is not always straightforward, but some human activities have clear impacts. These include land-use change, land management and land degradation (erosion, compaction, sealing and salinization). The intensity of land use also exerts a great impact on soils, and soils are also subject to indirect impacts arising from human activity, such as acid deposition (sulphur and nitrogen) and heavy metal pollution. In this critical review, we report the state-of-the-art understanding of these global change pressures on soils, identify knowledge gaps and research challenges and highlight actions and policies to minimize adverse environmental impacts arising from these global change drivers. Soils are central to considerations of what constitutes sustainable intensification. Therefore, ensuring that vulnerable and high environmental value soils are considered when protecting important habitats and ecosystems, will help to reduce the pressure on land from global change drivers. To ensure that soils are protected as part of wider environmental efforts, a global soil resilience programme should be considered, to monitor, recover or sustain soil fertility and function, and to enhance the ecosystem services provided by soils. Soils cannot, and should not, be considered in isolation of the ecosystems that they underpin and vice versa. The role of soils in supporting ecosystems and natural capital needs greater recognition. The lasting legacy of the International Year of Soils in 2015 should be to put soils at the centre of policy supporting environmental protection and sustainable development.

/pdf/global-change-pressures-on-soils-from-land-use-and-187jshfbt1.pdf

Global change pressures on soils from land use and management.

Tropical forests house over half of Earth’s biodiversity and are an important influence on the climate system. These forests are experiencing escalating human influence, altering their health and the provision of important ecosystem functions and services. Impacts started with hunting and millennia-old megafaunal extinctions (phase I), continuing via low-intensity shifting cultivation (phase II), to today’s global integration, dominated by intensive permanent agriculture, industrial logging, and attendant fires and fragmentation (phase III). Such ongoing pressures, together with an intensification of global environmental change, may severely degrade forests in the future (phase IV, global simplification) unless new “development without destruction” pathways are established alongside climate change–resilient landscape designs.

/pdf/increasing-human-dominance-of-tropical-forests-35o8iyniwg.pdf

Increasing human dominance of tropical forests.

Protected areas in tropical countries are managed under different governance regimes, the relative effectiveness of which in avoiding deforestation has been the subject of recent debates. Participants in these debates answer appeals for more strict protection with the argument that sustainable use areas and indigenous lands can balance deforestation pressures by leveraging local support to create and enforce protective regulations. Which protection strategy is more effective can also depend on (i) the level of deforestation pressures to which an area is exposed and (ii) the intensity of government enforcement. We examine this relationship empirically, using data from 292 protected areas in the Brazilian Amazon. We show that, for any given level of deforestation pressure, strictly protected areas consistently avoided more deforestation than sustainable use areas. Indigenous lands were particularly effective at avoiding deforestation in locations with high deforestation pressure. Findings were stable across two time periods featuring major shifts in the intensity of government enforcement. We also observed shifting trends in the location of protected areas, documenting that between 2000 and 2005 strictly protected areas were more likely to be established in high-pressure locations than in sustainable use areas and indigenous lands. Our findings confirm that all protection regimes helped reduce deforestation in the Brazilian Amazon.

https://www.pnas.org/content/pnas/110/13/4956.full.pdf

Governance regime and location influence avoided deforestation success of protected areas in the Brazilian Amazon

The dominant models explaining tree species diversity and distribution pat- terns in tropical forests are the Janzen-Connell and Recruitment Limitation models, neither of which considers the effect of long-distance seed dispersal on seed survival, seedling establishment, or the aggregated distributions of trees empirically observed at mesoscales in tropical forests. At a neotropical forest site (Maracai Island Ecological Reserve, Roraima, Brazil), we experimentally reproduced long-distance clumped seed dispersal by tapirs for the palm Maximiliana maripa. Such dispersal protects seeds from attack by species-specific bruchid beetles by (1) covering them in protective fecal material and (2) placing them in sites distant from conspecific adult tree aggregations, where beetles are less active. En- docarps distant from parent patches survived bruchid attack at a significantly higher rate than those in parent patches, as did in-feces endocarps compared to clean endocarps. A significant interaction effect between distance from patches and feces treatment showed that feces conferred protection to seeds within a parent patch but did not appear to confer additional protection to seeds already protected by distance from the parent patch. A me- soscale map compiled from aerial photography, satellite imagery, and air- and ground- truthing revealed an aggregated pattern of M. maripa palms associated with tapir latrine sites, supporting the view that long-distance seed dispersal by tapirs is responsible for the generation of palm patches and potentially important in forest-savanna boundary dynamics. We conclude that seed shadows and survival rates can justifiably be studied at the scale of tree aggregations rather than at the scale of individual trees, and that long-distance seed dispersal is neither rare nor unpredictable once we understand the movements and behavior of large, mobile animals.

http://tapiruscol.tripod.com/recursos/Fragoso2003.pdf

Long‐distance seed dispersal by tapirs increases seed survival and aggregates tropical trees

We radio-tracked five red-rumped agoutis (Dasyprocta leporina) for two to nine months each at the Estacao Ecologica Ilha de Maraca in the northern Brazilian Amazon. Agoutis fed primarily on seeds and pulp but also ate cotyledons, leaves, flowers, and invertebrates. Three plant species made up 63 percent of the feeding observations. Home range size varied from 3 to 8.5 ha. High-use areas and home range boundaries shifted from the season of high fruit availability to the season of low fruit availability as different individual trees became the focus of feeding activities. Agoutis foraged preferentially within conspecific patches of preferred fruit species and concentrated their feeding and scatterhoarding activities near individual fruiting trees. These results suggest that agoutis, as extremely short-distance seed dispersers, may contribute to the aggregated dispersion pattern of large-seeded tropical forest trees.

Red-rumped Agouti (Dasyprocta leporina) Home Range Use in an Amazonian Forest: Implications for the Aggregated Distribution of Forest Trees

Introduction1. Wildlife Conservation and Management in South and Central America: Multiple Pressures and Innovative solutions, by Jos M. V. Fragoso, Richard E. Bodmer and Kirsten M. SilviusPart I. Local Peoples and Community Management 2. Wildlife management strategies with the Embera people in the Utria National Park, by Choc , Colombia, Astrid Ulloa, Claudia Campos, and Heidi Rubio-Torgler3. Bridging the gap between western scientific and traditional indigenous wildlife management, by Kirsten M. Silvius4. Techniques to increase community participation in wildlife management programs: general approaches, by Wendy R. Townsend5. Community-based wildlife management in the Gran Chaco, by Bolivia, Andrew J. Noss and Michael Painter6. Fisheries Management and Conservation in the Amazon V rzea Floodplain, by William G. R. Crampton, Leandro Castello and Joao Paulo Viana7. Fisheries Management in the Mamirau Sustainable Development Reserve, by William G. R. Crampton, Joao Paulo Viana, Leandro Castello and Jos Mar a B. Dam8. Hunting effort analysis by rural communities in Northeastern Peru, by Pablo E. Puertas and Richard E. BodmerPart II. Economic Considerations 9. Community management of fishery resources in the Mamirau Sustainable Development Reserve, by Amazonas, BrazilJoao Paulo Viana, Jos Maria B. Damasceno, Leandro Castello, Wi10. Community ownership and live Shearing of vicu as in Peru, by Catherine T. Sahley, Jorge Torres Vargas and Jes s S nchez Valdivia11. Captive breeding programs as an alternative for wildlife conservation in Brazil, by Sergio Nogueira-Filho and Selene Siqueira da Cunha Nogueira12. Economic Analysis of Wildlife Use in the Peruvian Amazon, by Richard Bodmer, and Eterzit Pezo Lozano and Tula G. FangPart III. Fragmentation and other non-harvest human impacts 13. Population management of mammals in Atlantic Forest fragments of Brazil, by Laury Cullen Jr., Richard E. Bodmer, Claudio Valladares-P dua, and Jonathan D. B14. Human pressure, by abundance and spatial distribution of Orinoco Crocodiles in the Cojedes River sy15. Impacts of Damming on Primate Community Sructure in the Amazon-A Case Study of the Samuel Dam, by Rond nia, Brazil, Rosa M. Lemos de S 16. Resource partitioning of pampas deer, by brocket deer and cattle in the Pantanal, Brazil, Laurenz Pinder17. Ecology and conservation of the Jaguar in Igua u National Park, by Peter G. Crawshaw Jr., Jan K. M hler, Cibele Indrusiak, Sandra M.C. Cavalcanti, 18. Local white-lipped peccary (Tayassu pecari) population declines in Amazonia: Migration, by overhunting or epidemic?, Jos M. V. FragosoPart IV. Hunting Impacts--biological basis and rationale for sustainability 19. Evaluating the sustainability of hunting in the Neotropics, by Richard E. Bodmer and John G. Robinson20. Hunting sustainability of ungulate populations in the Lacandon forest, by Mexico, Eduardo J. Naranjo, Jorge E. Bola os, Michelle M. Guerra, and Richard E.21. Title: Conservation of economically important birds in seasonally-flooded forests of the northeastern Peruvian Amazon, by Jos A. Gonz lez22. Patterns of use and hunting of turtles in the Mamirau Sustainable Development Reserve, by Amazonas, Brazil, Augusto Fachin Teran, Richard C. Vogt, and John B. Thorbjarnar23. Fisheries, by Fishing Effort and Fish Consumption in the Pacaya-Samiria National Reserve and i24. Title: Implications of the spatial structure of game populations for the sustainability of hunting in the Neotropics, by Andr s J. Novaro25. Hunting and wildlife management in French Guiana: Current aspects and future prospects, by C cile Richard-Hansen and Eric Hansen

People in nature : wildlife conservation in South and Central America

Indigenous people of the Rupununi region of Amazonian Guyana interact with their natural environment through hunting and subsistence agriculture. To date the sustainability of indigenous livelihoods has been analyzed by modeling either hunting or forest clearing. Here we develop a holistic model framework with agent-based modeling to examine interactions between demographic growth, hunting, subsistence agriculture, land cover change, and animal population in the Rupununi. We use an extensive field dataset from social surveys, animal observation records and hunting kill locations along with satellite images. The model exhibits feedback loops between a growing human population and depletion of local natural resources. Our model can reproduce the population size of two different villages along with landscape patterns without further calibration. Our model can be used for understanding the conditions of sustainability for indigenous communities relying on subsistence agriculture and hunting, and for scenario analyses to examine the implications of external interventions.

Kirsten M. Silvius

Papers

Governance regime and location influence avoided deforestation success of protected areas in the Brazilian Amazon

Long‐distance seed dispersal by tapirs increases seed survival and aggregates tropical trees

Red-rumped Agouti (Dasyprocta leporina) Home Range Use in an Amazonian Forest: Implications for the Aggregated Distribution of Forest Trees

People in nature : wildlife conservation in South and Central America

Agent-based modeling of hunting and subsistence agriculture on indigenous lands: Understanding interactions between social and ecological systems