This book is a treasure trove. It contains 24 papers contributed to the Second Conference on Conservation Biology, sponsored by the School of Natural Resources at the University of Michigan, in May 1985 Editor Michael Soul6 has organized these papers into sections on The Fitness and Viability of Populations; Patterns of Diversity and Rarity; The Effects of Fragmentation; Community Processes; Sensitive Habitats; and Integrating with the Real World. One of Soulr’s goals was to provide an \"upto-date synthesis\" of the field, and, even given the natural limitations of symposium volumes, he has succeeded well. Soul6 has written commentaries that artfully cobble together the various sections of the book, and the structure nicely reflects the internal consistency and logic of conservation biology, a discipline that has matured rapidly in the nine years since the first Conservation Biology Conference at UC-San Diego in 19781. The field can no longer be mistaken for a hodge-podge of borrowed techniques and theories, but is a synthetic academic discipline in its own rightz. That it is also of pragmatic necessity for slowing the loss of species does nothing to detract from what Soul63 has called its \"great intellectual value.\" Soulr’s book is an excellent introduction to the breadth and depth of conservation biology. Although the included papers are founded in specialized research, most of them are nonetheless accessible to the nonspecialist. For example, Cody’s chapter on diversity, rarity, and conservation in Mediterranean-climate regions not only covers the diversity of the characteristic vegetation type, but begins with a clear, general introduction to the alpha, beta, and gamma levels of diversity. Templeton’s chapter on coadaptation and outbreeding depression explains the ins and outs of out-breeding depression, giving one particularly striking example: When the genes of a successfully reproducing population of European ibex (Capra ibex ibex) that lived in Austria were polluted with genes from subspecies originating in Turkey and Sinai, the hybrid females gave birth in February, the coldest month of the year. Understandably, the population went extinct. Rabinowitz, Cairns, and Dillon, although focusing on the flora of the British isles, discuss rarity in general and tell the novice the perhaps surprising fact that there are at least six types of rarity--not only are there the \"rare\" species that most commonly come to mind, those that have small populations restricted to localized geographic regions, but there are also rarities that are less intuitively obvious. One of these, the knotroot bristlegrass, Setaria geniculata, has a wide geographical distribution and occurs in many habitat types, but is nevertheless rare everywhere. Not surprisingly, the conservation prescriptions differ for different types of rarity, geographically restricted habitat specialists typically needing the most care. Many contributions to the book reflect the rapid widening of the discipline’s horizons: Dobson and Mays’ chapter on disease and conservation shows how recent theoretical developments in epidemiology may be used to mitigate the often overlooked dangers presented by disease to reduced and fragmented populations. Several chapters, including those by Lovejoy et al. and Wilcove, McLellan, and Dobson, illustrate how recent studies of edge effects are revolutionizing our assumptions about how well species can survive in small reserves--edge effects, including drying of vegetation and increased predation on birds’ nests, can reach hundreds of meters into forest remnants to decrease the abundance of forest species. Exciting work on the genetics of small populations, as reported in Templeton’s chapter, can be used in managing small populations so as to prevent loss of fitness caused by inbreeding depression, outbreeding depression, or genetic drift. One of the book’s major lessons is that successful conservation will depend upon our understanding the extremely complex biological world at all levels, from the gene to the ecosystem, from the theoretical to the practical, from the biological to the social. Even seemingly esoteric studies can yield insights of profound practical importance. From Templeton’s observations on the genetics of small populations comes this conclusion: because species are made up of a constantly changing (evolving) mix of genetic types, it is an impossibility and a mistake to try to preserve an endangered \"species\" as an unchanging ideal type, composed only of present-day traits. Better to realize that species \"are evolutionary lineages\" that will change under both natural and captive conditions and that conservation biologists should \"use evolutionary change as a beneficial management tool rather than to regard it as a deleterious situation that must be prevented at all costs.\" This means, among other things, that a hybrid dusky seaside sparrow may be better than none at all. Many of the chapters, including those in the section \"Interacting with the Real World,\" stress an awareness that successful long-term conservation depends upon considering the world outside the reserve as well as that within. They know that activities near reserve boundaries,_like fuel harvesting or pesticide use, will affect the species inside, and that local people must have some stake in the protected biological resources. Thus, increasingly, conservation biology is drawing on the social sciences, recognizing that consideration of economic development must complement knowledge that is purely biological. Cairns’ chapter, Restoration, Reclamation, and Regeneration, discusses the potentially important role of ecosystem reconstruction in the conservation of vulnerable species, recognizing that full restoration to

Conservation Biology: The Science of Scarcity and Diversity

General principles about the consequences of seed dispersal by animals for the structure and dynamics of plant populations and communities remain elusive. This is in part because seed deposition patterns emerge from interactions between frugivore behaviour and the distribution of food resources, both of which can vary over space and time. Here we advocate a frugivore-centred, process-based, synthetic approach to seed dispersal research that integrates seed dispersal ecology and animal movement across multiple spatio-temporal scales. To guide this synthesis, we survey existing literature using paradigms from seed dispersal and animal movement. Specifically, studies are discussed with respect to five criteria: selection of focal organisms (animal or plant); measurement of animal movement; characterization of seed shadow; animal, plant and environmental factors included in the study; and scales of the study. Most studies focused on either frugivores or plants and characterized seed shadows directly by combining gut retention time with animal movement data or indirectly by conducting maternity analysis of seeds. Although organismal traits and environmental factors were often measured, they were seldom used to characterize seed shadows. Multi-scale analyses were rare, with seed shadows mostly characterized at fine spatial scales, over single fruiting seasons, and for individual dispersers. Novel animal- and seed-tracking technologies, remote environmental monitoring tools, and advances in analytical methods can enable effective implementation of a hierarchical mechanistic approach to the study of seed dispersal. This kind of mechanistic approach will provide novel insights regarding the complex interplay between the factors that modulate animal behaviour and subsequently influence seed dispersal patterns across spatial and temporal scales.

/pdf/integrating-frugivory-and-animal-movement-a-review-of-the-4pfoecr3la.pdf

Integrating frugivory and animal movement: a review of the evidence and implications for scaling seed dispersal.

Aim Large-bodied vertebrates often have a dramatic role in ecosystem function through herbivory, trampling, seed dispersal and nutrient cycling. The iconic Galapagos tortoises (Chelonoidis nigra) are the largest extant terrestrial ectotherms, yet their ecology is poorly known. Large body size should confer a generalist diet, benign digestive processes and long-distance ranging ability, rendering giant tortoises adept seed dispersers. We sought to determine the extent of seed dispersal by Galapagos tortoises and their impact on seed germination for selected species, and to assess potential impacts of tortoise dispersal on the vegetation dynamics of the Galapagos. Location Galapagos, Ecuador. Methods To determine the number of seeds dispersed we identified and counted intact seeds from 120 fresh dung piles in both agricultural and national park land. To estimate the distance over which tortoises move seeds we used estimated digesta retention times from captive tortoises as a proxy for retention times of wild tortoises and tortoise movement data obtained from GPS telemetry. We conducted germination trials for five plant species to determine whether tortoise processing influenced germination success. Results In our dung sample, we found intact seeds from >45 plant species, of which 11 were from introduced species. Tortoises defecated, on average, 464 (SE 95) seeds and 2.8 (SE 0.2) species per dung pile. Seed numbers were dominated by introduced species, particularly in agricultural land. Tortoises frequently moved seeds over long distances; during mean digesta retention times (12days) tortoises moved an average of 394m (SE 34) and a maximum of 4355m over the longest recorded retention time (28days). We did not find evidence that tortoise ingestion or the presence of dung influenced seed germination success. Main conclusions Galapagos tortoises are prodigious seed dispersers, regularly moving large quantities of seeds over long distances. This may confer important advantages to tortoise-dispersed species, including transport of seeds away from the parent plants into sites favourable for germination. More extensive research is needed to quantify germination success, recruitment to adulthood and demography of plants under natural conditions, with and without tortoise dispersal, to determine the seed dispersal effectiveness of Galapagos tortoises.

Seed dispersal by Galapagos tortoises

Human welfare depends directly or indirectly on the services provided by ecosystems. Amphibians and reptiles represent a high proportion of global species diversity and include species that are widely distributed throughout the world and play a variety of roles that benefit humans. The aim of this study was to identify and describe the ecosystem services provided by amphibians and reptiles in Neotropical ecosystems to evaluate the contribution of these highly diverse groups to human welfare. We conducted a literature review of articles and books from databases and university libraries and collected data from 106 studies. Amphibians and reptiles contributed directly and indirectly to the four types of ecosystem services: provisioning, regulating, cultural, and supporting. Most available studies reported the use of direct services from reptiles and indirect services from amphibians. Although eight ecosystem services were identified, most studies focused on reptiles as seed dispersers and protein sources. Bi...

https://www.tandfonline.com/doi/pdf/10.1080/21513732.2013.821168

Ecosystem services provided by amphibians and reptiles in Neotropical ecosystems

Amphibians and reptiles (herps) are the most abundant and diverse vertebrate taxa in tropical ecosystems. Nevertheless, little is known about their role in maintaining and regulating ecosystems functions and, by extension, their potential value for supporting ecosystems services. Here, we review research on the ecological functions of Neotropical herps, in different sources (the bibliographic databases, book chapters, etc.). A total of 167 Neotropical herpetology studies published over the last four decades (1970 to 2014) were reviewed, providing information on more than 100 species that contribute to at least five categories of ecological functions: i) nutrient cycling; ii) bioturbation; iii) pollination; iv) seed dispersal, and v) energy flow through ecosystems and the mechanisms behind these, through the study of functional traits and analysis of ecological processes. Many of these functions provide key ecosystems, such as biological pest control, seed dispersal and water quality. By knowing and understanding the functions that perform the herps in ecosystems, management plans for cultural landscapes, restoration or recovery projects of landscapes that involve aquatic and terrestrial systems, development of comprehensive plans and detailed conservation of species and ecosystems may be structured in a more appropriate way. Besides information gaps identified in this review, this contribution explores these issues in terms of better understanding of key questions in the study of ecosystem services and biodiversity and, also, of how these services are generated.

/pdf/ecological-functions-of-neotropical-amphibians-and-reptiles-1p0ib78oxk.pdf

Ecological functions of neotropical amphibians and reptiles: a review

The Amazonian tortoise Geochelone denticulata may play an important role in forest dynamics due to its highly frugivorous diet, ability to disperse viable seeds, and predilection for resting in forest gaps for thermoregulation. The purpose of our study was to evaluate the species' effectiveness as a seed disperser. We measured dispersal quantity (abundance of seeds in feces, frequency of droppings, and population density of the disperser) and dispersal quality (movement patterns, habitat use, germination rates of dispersed seeds, and recruitment probabilities of seedlings) in a SW Amazonian forest, in Peru. Population density was calculated by mark-recapture and line-transect methods. Eight individuals were radio-tracked to monitor habitat use. Diet was described from fecal samples, which were washed to count seeds and for germination experiments. Seedling survival in different environmental conditions was monitored for three plant species. Population densities with mark-recapture estimates (0.15-0.31 individuals/ha) were much higher than with line transects estimates (0.0025 individuals/ha). Diet included fruit of 55 different plant species. Dispersed seeds had high germination rates (average 76%). In spite of their low activity, we documented long seed dispersal distances (average 89.6 m). Tortoises showed a marked preference for the open-canopy swampy forest, where long term recruitment was not favorable for seedlings of the species examined. However, the high solar radiation in this forest type promoted survival of pioneer seedlings in the short term. In conclusion, while G. denticulata did not perform a very efficient role in terms of the quantity of seed dispersal, the species can be considered efficient in many aspects of dispersal quality.

Seed dispersal, habitat selection and movement patterns in the Amazonian tortoise, Geochelone denticulata

Most studies on seed dispersal in time have focused on seed dormancy and the physiological trig- gers for germination. However, seed dispersed by animals with low metabolic and moving rates, and long gut- passage times such as terrestrial turtles, could be considered another type of dispersal in time. This study tests the hypothesis that seeds dispersed in time may lower predation rates. We predicted that seeds deposited below parent trees after fruiting fall has finished is advantageous to minimize seed predators and should show higher survival rates. Four Amazonian plant species, Dicranostyles ampla, Oenocarpus bataua, Guatteria atabapensis and Ocotea floribunda, were tested for seed survival probabilities in two periods: during fruiting and 10-21 days after fruiting. Experiments were carried out in two biological stations located in the Colombian Amazon (Caparu and Zafire Biological Stations). Seed predation was high and mainly caused by non-vertebrates. Out of the four plant species tested, only Guatteria atabapensis supported the time escape hypothesis. For this species, seed predation by vertebrates after the fruiting period increased (from 4.1% to 9.2%) while seed predation by non- vertebrates decreased (from 54.0% to 40.2%). in contrast, seed predation by vertebrates and by non-vertebrates after the fruiting period in D. ampla increased (from 7.9% to 22.8% and from 40.4% to 50.6%, respectively), suggesting predator satiation. Results suggest that for some species dispersal in time could be advantageous to avoid some type of seed predators. Escape in time could be an additional dimension in which seeds may reach adequate sites for recruitment. Thus, future studies should be address to better understand the survival advantages given by an endozoochory time-dispersal process. Rev. Biol. Trop. 59 (4): 1795-1803. Epub 2011 December 01.

https://revista-ciencia-tecnologia.ucr.ac.cr/index.php/rbt/article/download/33186/32725

Adriana Guzmán

Papers

Seed dispersal, habitat selection and movement patterns in the Amazonian tortoise, Geochelone denticulata

A new hypothesis for the importance of seed dispersal in time