Keystone Resource Research Articles

The phenology of dioecious Ficus spp. tree species and its importance for forest restoration projects

Ficus spp. are keystone tree species in tropical forest ecosystems and therefore, it is vital to include them in tree planting for forest restoration programs. However, lack of knowledge about critical aspects of their reproductive ecology currently limits their use, particularly optimal seed collection times and potential interruption of their highly specialized pollination mechanisms. Therefore, the reproductive phenology of seven dioecious Ficus species ( Ficus auriculata, F. fulva, F. hispida, F. oligodon, F. semicordata, F. triloba and F. variegata) was studied at Doi Suthep–Pui National Park, Northern Thailand, in order to provide useful data to support forest restoration projects. The fig crops on male and female trees of each species were quantified monthly over a full annual cycle (March 2008–February 2009), using the canopy density method. At the population-level, most species produced figs all year round, but fig abundance varied seasonally. Maximum production of ripe figs by female (i.e. seed-producing) trees of most species occurred in the rainy season (May–August, except for F. triloba), while the main fig crop of male (i.e. wasp-producing) trees peaked 1–3 months before female trees. Four species F. auriculata, F. fulva, F. oligodon, and F. variegata presented critical bottleneck periods for wasp survival, especially during the rainy season, when the wasp-producing figs of male trees were least abundant. The study generated scientifically-based recommendations that will be useful for development of efficient forest restoration programs that maintain keystone resources in tropical forest ecosystems such as (i) optimum time and place for seed collection, (ii) recommendations on the propagation of dioecious fig species, (iii) optimum planting sites for each species and (iv) forest restoration plans to sustain the obligate ecological relationships between fig-trees and their pollinators.

Abundance of Jackfruit (Artocarpus heterophyllus) Affects Group Characteristics and Use of Space by Golden-Headed Lion Tamarins (Leontopithecus chrysomelas) in Cabruca Agroforest

Cabruca is an agroforest of cacao trees shaded by native forest trees. It is the predominant vegetation type throughout eastern part of the range of the golden-headed lion tamarins, Leontopithecus chrysomelas, an endangered primate endemic to Atlantic Forest. Understanding how lion tamarins use this agroforest is a conservation priority. To address this question, we documented the diet, home range size, group sizes and composition, density, number of litters and body condition of lion tamarins living in cabruca, and other habitats. Jackfruit, Artocarpus heterophyllus, was the most used species used by lion tamarins in cabruca and was widely available and used throughout the year. In cabruca, home range size was the smallest (22-28ha) and density of lion tamarins was the highest (1.7ind/ha) reported for the species. Group size averaged 7.4 individuals and was not significantly different among the vegetation types. In cabruca, groups produced one or two litters a year, and all litters were twins. Adult males in cabruca were significantly heavier than males in primary forest. Our study is the first to demonstrate that breeding groups of golden-headed lion tamarins can survive and reproduce entirely within cabruca agroforest. Jackfruit proved to be a keystone resource for lion tamarins in cabruca, and bromeliads were important as an animal prey foraging microhabitat. In cases where cabruca contains concentrated resources, such as jackfruit and bromeliads, lion tamarins may not only survive and reproduce but may fare better than in other forest types, at least for body condition and reproduction.

The contribution of mistletoes to nutrient returns: Evidence for a critical role in nutrient cycling

AbstractBoth nutrient cycling and nutrient relationships between mistletoe and host have been widely studied; yet it is unclear whether high nutrient concentrations commonly found in mistletoes affect rates of nutrient cycling. To address this question, we assessed 13 elements in the leaf litter of a temperate eucalypt forest in southern New South Wales, comparing concentrations from trees (Eucalyptus blakelyi, E. dwyeri, and E. dealbata) with and without the hemiparasitic mistletoe Amyema miquelii. Results were in accord with previous research on fresh leaves showing that concentrations of many elements were higher in the mistletoe than the host. This was not the case for all elements; most notably for N, where concentrations were significantly lower in the mistletoe. However, the return of all elements increased with mistletoe infection because of the combined effect of enrichment in mistletoe tissues and high rates of mistletoe litterfall. Annual returns of N and P in leaf litter increased by a factor of 1.65 and 3 respectively, with the greatest increase being for K by a factor of 43 in spring. These increased element returns were not significantly influenced by any changes in host leaf litter quality, as mistletoe infection was not found to affect host element concentrations. Mistletoe infection also altered the spatial and temporal distribution of element returns because of the patchy occurrence of mistletoes and extended period of mistletoe litterfall compared with the host. These findings provide a mechanistic explanation for the role of mistletoes as a keystone resource and, together with comparable results from root‐parasitic plants in boreal tundra and cool‐temperate grasslands, suggest that enhancing nutrient return rates may be a generalized property of parasitic plants.

Foraging ecology of Vicuña, Vicugna vicugna, in dry Puna of Argentina

Vicuña, Vicugna vicugna, is one of the few large native herbivores of South American and it is considered a keystone resource for the Andean Region. We studied foraging ecology of free ranging vicuñas at Laguna Blanca MAB-UNESCO Biosphere Reserve (Catamarca, Argentina), within dry Puna environment. Vicuñas showed a stable diet throughout the year, with marked differences at spatial scale. Diet of vicuñas included vegetation from all habitats, all vegetation strata and all functional groups of plants, suggesting that vicuñas can use a large range of plant species that are distributed in almost all portions of their range (they used 39 of 75 available plant species), behaving as a generalist ungulate. Vicuñas consumed large proportion of grasses (59–72%) and shrubs represented 16–19% of vicuña overall diet, reaching 45% at local sites, so we proposed that in this puna ecosystem vicuñas do not behave as strict grazers. Although vicuñas showed high diet plasticity, only two grasses, Panicum chloroleucum and Distichlis spp. represented nearly 50% of the diet. In relation to photosynthesis pathways of the plants, C 4 grasses contributed higher to proportions in diet than C 3 grasses. Vicuñas showed a selectivity foraging behaviour by consuming swamp forages, low and medium vegetation strata, and a few plant species in more proportion to their availability. Vicuñas did not eat plant species with more overall nutritional quality in higher proportion than species with less nutritional contents. However, the consumption of steppe grasses was in direct proportion to its crude protein content. This work brings a broad description of the foraging ecology of southern subspecies of vicuña, V. v. vicugna, by researching botanical composition and nutritional quality of the diet. These features of diet of vicuñas can be considered as part of its wide range of feeding responses to live in the poor environment of altiplano.

Adaptation of the externally feeding bug Elasmucha necopinata (Hemiptera: Acanthosomatidae) to its fig host

Figs (Ficus) are keystone resources that maintain tropical biodiversity. Pollinators, non-pollinating fig wasps, and some insects that feed internally in syconia (the fruits of figs) synchronize their developmental stages with syconia. Other insects feed and develop externally on the syconia but little is known about adaptations in these insects. We investigated the life cycle of Elasmucha necopinata, a bug that develops externally on the syconia of Ficus hispida, a functionally dioecious fig. The bug oviposits about a week after fig receptivity, the nymphs feed externally on the syconia and eclosion occurs when the syconia mature. Thus, nymphs synchronize their developmental stages with the male syconia of F. hispida. Although the relationship does not appear to be mutualistic, we suggest that E. necopinata, feeding externally, has adapted to figs, in a similar way to Agaonid fig wasps that live internally. We believe that this is the first direct evidence of adaptation of an externally feeding insect to figs.

Mobilizing Rivers: Hydro-Electricity, the State, and World War II in Canada

World War II drove an unprecedented search for resources at a global scale to supply military activity in Europe, Asia, and beyond. This article contributes to recent debates about the environmental consequences of global warfare by examining how total war imposed political pressures on states, industries, and citizens that conditioned the resource development process and overrode preexisting constraints. Examining Canada's role as a supply warehouse for the Allies, the analysis focuses on a keystone resource, hydro-electricity, which powered a wide range of resource processing and manufacturing activity. To mobilize the economy, the Canadian state ordered the damming of rivers, interconnection of systems, and rationalization of industrial and consumer demands. Drawing on a wide range of archives, I examine the wartime politics of resource development, the centralizing strategy of the federal government, and the role of international governments in shaping the development agenda. Global war redrew the rules of river development and hydro power, created the opportunity for new state powers, and weakened the position of river development critics. The case allows us to consider the direct and indirect effects of global military activity in shaping resource development at a number of geographical and temporal scales.

Parasitic plants as facilitators: more Dryad than Dracula?

Summary Despite being components of most vegetation types, the community‐level effects of parasitic plants are often ignored. The few studies adopting a broader view have revealed that these plants mediate a series of direct and indirect competitive and facilitative effects on community structure and ecosystem processes. I summarize findings from the two best‐studied systems: a set of experimental and manipulative studies from northern Sweden and an integrated research programme in southern Australia, both focusing on the most abundant hemiparasite in the region –Bartsia alpina (Orobanchaceae; Lamiales) and Amyema miquelii (Loranthaceae; Santalales), respectively. Despite broad‐based differences between these regions, their vegetation types and biotic constituents, rates of litter‐fall, litter decomposition, nutrient return and plant growth all increased near the hemiparasites in both cases. This leads to changes in the abundance of other plants and the increased species richness and total biomass reflects an indirect form of facilitation. In addition to reallocation of nutrients from host tissues, some of the additional nutrients may be excreted by other organisms, such as visiting pollinators, seed dispersers, herbivores and members of below‐ground decomposer communities. Small‐scale heterogeneity in nutrient availability could provide a mechanistic process underlying the role of parasitic plants as keystone resources. Parasitic plants can be regarded as either malevolent predators (Dracula) or charitable benefactors(Robin Hood), but may be better described as Dryads (Greek deities associated with specific trees, which, in addition to being reliant on their host for their wellbeing, affect nearby trees and visiting animals, rendering the surrounding stand a sacred grove). Synthesis. The Dryad role may be applicable to a wide range of facilitators, whereby indirect interactions with other organisms affect both hosts and adjacent plants, augmenting direct plant–plant interactions. However, while consistent with both case studies and information from studies of other parasitic plants, this role may be most apparent in low productivity systems. Addition, removal and animal exclosure experiments are highlighted as useful approaches to quantify the community‐level influence of parasitic plants, in addition to dedicated work on the below‐ground influences of parasitic plants.

Behavior of tamarins, tanagers and manakins foraging in a strangler fig (Ficus sp.) in Suriname, South America: implications for seed dispersal

The behavior of foragers can directly affect the dispersal of seeds. Strangler figs are keystone resources throughout the tropics and are important resources for both primates and birds. We examined the foraging behavior of golden-handed tamarins and four bird species in a strangler fig to see how these behaviors might affect the dispersal of fig seeds. Tamarins removed fruit at a faster rate than did any of the bird species examined. Additionally, tamarins tended to swallow figs whole whereas birds tended to drop figs once they were processed. Tamarins visiting fig trees ingest large quantities of fig seeds that may be deposited throughout the forest. Birds on the other hand tended to slowly process fruits near the fig tree and drop processed fruit containing large quantities of seeds. Future studies need to be conducted to ascertain differences in post dispersal seed fate.

Sacoglottis gabonensis– a keystone fruit for forest elephants in the Réserve de Faune du Petit Loango, Gabon

AbstractThis study suggests that the fruits of Sacoglottis gabonensis (Baill.) Urb. (Humiriaceae) are a keystone resource for forest elephants (Loxodonta cyclotis Matschie) in a coastal rain forest, the Réserve de Faune du Petit Loango, Gabon (now part of Loango National Park). Faecal counts demonstrated that forest elephants used Sacoglottis‐dominated forest more when Sacoglottis was abundant and electivity indices suggest that Sacoglottis is a preferred food. The flora of Petit Loango is characterized by the absence of herbaceous vegetation such as Marantaceae and Zingiberaceae, and during the prolonged dry season few fleshy fruits are present other than Sacoglottis fruits, which are produced in a glut during this time. While inter‐annual fruiting reliability remains to be confirmed, fruit production in 1998 and high stem density relative to other study sites provide indirect evidence that Sacoglottis fruits are a reliable inter‐annual resource at Petit Loango. It is thus proposed that Sacoglottis gabonensis fruits fulfil an important role as a keystone ‘fallback’ resource for forest elephants during the dry season at Petit Loango.

First contact: Understanding the relationship between hominoid incisor curvature and diet

Accurately interpreting fossil primate dietary behaviour is necessary to fully understand a species' ecology and connection to its environment. Traditional methods developed to infer diet from hominoid teeth successfully group taxa into broad dietary categories (i.e., folivore, frugivore) but often fail to represent the range of dietary variability characteristic of living apes. This oversimplification is not only a consequence of poor resolution, but may also reflect the use of similar fallback resources by closely related taxa with dissimilar diets. This study demonstrates that additional dietary specificity can be achieved using a morphometric approach to hominoid incisor curvature. High-resolution polynomial curve fitting (HR-PCF) was used to quantify the incisor curvatures of closely related hominoid taxa that have dissimilar diets but similar morphological adaptations to specific keystone resources (e.g., Gorilla gorilla beringei vs. G. g. gorilla). Given the key role of incisors in food processing, it is reasonable to assume that these teeth will be at least partially influenced by the unique selective pressures imposed by the mechanical loading specific to individual diets. Results from this study identify a strong correlation between hominoid dietary proportions and incisor linear dimensions and curvature, indicating that more pronounced incisor curvature is positively correlated with higher levels of frugivory. Hard-object frugivores have the greatest mesiodistal and cervico-incisal curvature and dedicated folivores have the least curved incisors. Mixed folivore/frugivores are morphological intermediates between dedicated folivores and hard- and soft-object frugivores. Mesiodistal curvature varied only in the degree of curvature; however, cervico-incisal curvature was shown to differ qualitatively between more frugivorous and more folivorous taxa. In addition to identifying a greater range of dietary variability among hominoids, this study also demonstrates that HR-PCF is capable of identifying morphological distinctions between closely related taxa with overlapping diets that rely on similar fallback foods (e.g., Pan paniscus vs. P. troglodytes).

Fruiting phenology of palms and trees in an Atlantic rainforest land-bridge island

Tropical forests show periods of scarcity and high fruit production in the same year and/or between years. Palms are an important component of Neotropical rainforests and a significant food resource for several frugivores. Therefore, their role as keystone resource may be exacerbated in highly impoverished areas. In Anchieta Island, São Paulo/Brazil, human settlements have modified and impoverished the forest, mainly through overharvesting and the introduction of exotic plants and several mammal species. We assessed the offer of fruits consumed by vertebrate frugivores at this island, the vegetation of which is belonging to the Brazilian Atlantic rainforest. We compared whether the fruiting patterns and fruit fall differ between palms and trees, and discuss the importance of palms as a food resource for frugivores and the implications for Anchieta Island conservation. Phenological patterns were seasonal for both trees and palms; however, the times of fruiting occurrence differed. Fruit fall biomass was at least twice lower than reported for other Atlantic rain forests and was also different between trees and palms. Palms contributed more than 80% of the overall fruit fall biomass. Palms may constitute an alternative food resource in periods of low fruit availability, although they do not provide resources for the entire assemblage of vertebrate frugivores. Energy-rich fruits, such as those produced by palms, may play an important role in the maintenance of frugivore populations in isolated, disturbed environments with a high density of vertebrate frugivores, low diversity of fruiting species and fruit biomass such as those found on Anchieta Island.

Ringtailed Lemurs: Behavioral Ecology and Biology

Ringtailed lemurs are truly the flagship species for Madagascar, given their recognizable features and a role as “King of the Lemurs” in a computer-animated film produced by DreamWorks Animation. Shortly before Ringtailed Lemur Biology was published, students conducting a primary school science project contacted me for information on population sizes of these amazing primates. I was embarrassed to admit that no such data existed at that time, despite the wealth of information on lemur behavior. The nascent primatologists were not impressed, given that their classmates had “tons of cool stuff” on other tropical mammals. In the future, I can point interested students to this book as the perfect place to get “cool stuff” on ringtailed lemurs. The book is organized into four sections: distribution, feeding and ranging, social behavior, and health and disease. The distribution section contains four chapters, two of which provide short overviews of the main sites where detailed field studies have been conducted. The other chapters in this section really shine. The first paper by Goodman et al. describes the biogeography of ringtailed lemurs, illustrating the ability of this species to survive in a variety of habitat types. The second paper by Sussman et al. integrates abundance patterns of ringtailed lemurs with satellite analysis of forest cover. The authors do a commendable job of interpreting their model. They also point out how omission and commission errors are serious issues in conservation models. By uniting data from an old discipline (biogeography) with a very new discipline (satellite imagery), Sussman et al. highlight the value of landscape approaches for studies of the conservation biology of mammals. This paper is a ‘must read’ for primatologists and mammologists pursuing similar work. The second section on feeding and ranging behaviors contains seven chapters, each of which highlights the importance of tamarind trees (Tamarindus indica) as a keystone resource for ringtailed lemurs. Soma’s chapter on exploitation of exotic food resources and the resulting population growth has important implications for lemur health, a topic explored in detail later in the book. The take-home message in this section is that if there are no tamarind trees, then J Mammal Evol (2008) 15:151–153 DOI 10.1007/s10914-007-9061-7

Acorn mast drives long-term dynamics of rodent and songbird populations

Resource pulses can have cascading effects on the dynamics of multiple trophic levels. Acorn mast is a pulsed resource in oak-dominated forests that has significant direct effects on acorn predators and indirect effects on their predators, prey, and pathogens. We evaluated changes in acorn mast, rodent abundance, raptor abundance, and reproductive success of a ground-nesting songbird over a 24-year period (1980-2004) in the southern Appalachian Mountains in an effort to determine the relationships among the four trophic levels. In particular, we examined the following: acorn mast from red oaks (Quercus rubra) and white oaks (Q. alba), abundance of white-footed mice (Peromyscus leucopus) and deer mice (P. maniculatus), population estimates of seven raptor species from three feeding guilds, and nest failure and number of juveniles of dark-eyed juncos (Junco hyemalis). Finally, we recorded seasonal temperature and precipitation to determine the effects of weather on each trophic level. We found that weather patterns had delayed effects of up to 3 years on these trophic interactions. Variation in acorn mast, the keystone resource in this community, was explained by weather conditions as far back as 2 years before the mast event. Acorn mast, in turn, was a strongly positive predictor of rodent abundance the following year, whereas spring and summer temperature and raptor abundance negatively affected rodent abundance. Dark-eyed junco nests were more likely to fail in years in which there were more rodents and raptors. Nest failure rate was a strong predictor of the number of juvenile juncos caught at the end of the summer. Our results improve our understanding of the complex ecological interactions in oak-dominated forests by illustrating the importance of abiotic and biotic factors at different trophic levels.

The Role of Endangered Species Reintroduction in Ecosystem Restoration: Tortoise–Cactus Interactions on Española Island, Galápagos

Abstract We evaluated the role that endangered species reintroduction efforts can play in the larger context of ecosystem restoration. To do so, we examined interactions between endangered giant tortoises (Geochelone nigra hoodensis), currently being reintroduced to Isla Española, Galápagos, and an arboreal cactus (Opuntia megasperma var. megasperma), which is itself endangered and a keystone resource for many animals on the island. We collected information on spatial patterns of occurrence of cacti, tortoises, and woody vegetation and compared recruitment of juvenile cacti in areas occupied versus unoccupied by tortoises. Reintroduced tortoises appeared to suppress cactus recruitment near the few remaining adult cacti at the study site, but facilitate it at longer distances, with tortoise–cactus interactions mediated by the presence of woody vegetation, which likely alters tortoise movements and thereby patterns of cactus seed dispersal. The net effect of tortoises on cacti appeared to be positive insofar as tortoise presence was associated with greater recruitment of juveniles into cactus populations. Our study provides support for reintroducing endangered reptiles and other animals to aid ecosystem restoration in areas where they might once have played an important role in grazing upon and dispersing plants.

Parasites boost productivity: effects of mistletoe on litterfall dynamics in a temperate Australian forest

The importance of litter in regulating ecosystem processes has long been recognised, with a growing appreciation of the differential contribution of various functional plant groups. Despite the ubiquity of mistletoes in terrestrial ecosystems and their prominence in ecological studies, they are one group that have been overlooked in litter research. This study evaluated the litter contribution from a hemiparasitic mistletoe, Amyema miquelii (Lehm. ex Miq.) Tiegh., in an open eucalypt forest (Eucalyptus blakelyi, E. dwyeri and E. dealbata), at three scales; the forest stand, single trees and individual mistletoes. Litter from mistletoes significantly increased overall litterfall by up to 189%, the amount of mistletoe litter being proportional to the mistletoe biomass in the canopy. The high litter input was due to a much higher rate of mistletoe leaf turnover than that of host trees; the host litterfall and rate of leaf turnover was not significantly affected by mistletoe presence. The additional litter from mistletoes also affected the spatial and temporal distribution of litterfall due to the patchy distribution of mistletoes and their prolonged period of high litterfall. Associated with these changes in litterfall was an increase in ground litter mass and plant productivity, which reflects similar findings with root-parasitic plants. These findings represent novel mechanisms underlying the role of mistletoes as keystone resources and provide further evidence of the importance of parasites in affecting trophic dynamics.

An exotic plantation crop as a keystone resource for an endemic megachiropteran, Pteropus rufus, in Madagascar

The single most important food source for Pteropus rufus at Berenty, in south-east Madagascar, is the pollen of Agave sisalana, a commercial species introduced to the area 60 y ago, which was widely available and constantly eaten by the bats during this 28-mo study. The diet of the bats at this site is unique in this respect when compared with P. rufus elsewhere in Madagascar and with other Pteropus species. The dietary breadth of P. rufus at Berenty is narrow, consisting of only 14 plant species, identified through microsopic faecal analysis and direct field observations, and three unidentified ones. The bats also eat locally cultivated and introduced fruits (Mangifera indica, Psidium cf. cattleianum, Sclerocarya caffra, Cordia sinensis and Hylocereus species) and native and endemic forest species (Tamarindus indica, Celtis philippensis, Ficus megapoda, F. grevei, F. pachyclada and Grewia species). The majority of the plant species used by P. rufus for food are located within the gallery forests of the Mandrare valley. No evidence of adjacent endemic spiny forest species was identified in their diet. Thus, conservation of the remaining gallery forest as well as retention of the sisal plantations is important to maintain the food sources of P. rufus at this site.

Food plant diversity as broad-scale determinant of avian frugivore richness

The causes of variation in animal species richness at large spatial scales are intensively debated. Here, we examine whether the diversity of food plants, contemporary climate and energy, or habitat heterogeneity determine species richness patterns of avian frugivores across sub-Saharan Africa. Path models indicate that species richness of Ficus (their fruits being one of the major food resources for frugivores in the tropics) has the strongest direct effect on richness of avian frugivores, whereas the influences of variables related to water-energy and habitat heterogeneity are mainly indirect. The importance of Ficus richness for richness of avian frugivores diminishes with decreasing specialization of birds on fruit eating, but is retained when accounting for spatial autocorrelation. We suggest that a positive relationship between food plant and frugivore species richness could result from niche assembly mechanisms (e.g. coevolutionary adaptations to fruit size, fruit colour or vertical stratification of fruit presentation) or, alternatively, from stochastic speciation-extinction processes. In any case, the close relationship between species richness of Ficus and avian frugivores suggests that figs are keystone resources for animal consumers, even at continental scales.

Seasonal Variations in Diet and Foraging Behavior of Ateles chamek in a Southern Amazonian Tropical Forest

I present data regarding the diet and feeding ecology of a spider monkey community at Lago Caiman in northeastern Bolivia. The community was highly frugivorous, only consuming significant amounts of folivorous material during times of relative fruit resource scarcity. Spider monkeys fed on parts of 86 plant species, but the majority of the diet comprised a few dominant fleshy fruit species that were available at temporally distinct periods across the year. Accordingly, I identified candidate keystone resources for the region and discuss the results with reference to previous studies on Ateles and the importance of considering keystone fruit resources in the management of forestry concessions.

Readers, Instruction, and the NRP

Are programs that emphasize systematic phonics instruction truly superior to other types of programs for young readers, as the National Reading Panel claims? The authors conducted a study of three different programs to see what kinds of readers are actually emerging from them. JESSICA, a second-grader in an urban school with a low socioeconomic profile, reads: But the nighttime tried to stand back down the stairs. So I caused it.1 Like her classmates, Jessica has learned to read words through systematic and explicit phonics instruction. She comes up with words that look and sound similar to the words on the page, but they do not always make sense in the sentence. She accepts this, seemingly unaware that the text is supposed to make sense. Jessica's repertoire of reading strategies is limited, and her comprehension is poor. Is this the kind of reading that we wish to promote? The pressure on schools to use programs of systematic and explicit phonics instruction is tremendous. The report of the National Reading Panel (NRP), a keystone resource for the Reading First program of the No Child Left Behind (NCLB) Act, used 38 studies to determine that explicit and systematic phonics instruction in the early grades is necessary.2 Though it is not clear how long lessons should run, how many letter/sound relationships should be learned, how much phonics should be covered, or the type of instruction needed, phonics is deemed necessary. The federal government severely restricts the range of reading programs that it will fund through NCLB to those that demonstrate a systematic and predominant emphasis on phonics. Only programs that are considered to be research-based, using a narrow medical model, are acceptable. Those who use other kinds of instruction that are based on other kinds of research risk forgoing federal funds. A case in point is New York City's run-in with federal agencies in which the phonics program the city tested in its schools was not considered research-based.3 In order to ensure funding, school districts are adopting or mandating single commercial programs, such as Direct Instruction or Open Court, which, at the core of instruction, impose extensive systematic and explicit skill approaches on all children. Studying Readers Much of the research used by the NRP and approved by NCLB measures reading achievement by means of word lists, short passages with blanks, and lists of non-words. Such research does not study the actual process of students reading real texts, which would make it possible to determine the impact of phonics instruction on the strategies young readers use, on how they comprehend, or on how they perceive the reading process. We developed a study to do just that. We examined the impact of three different reading programs used in our metropolitan area on the reading processes of second-graders who had been instructed with these programs since at least first grade. Two were commercial programs that used explicit and systematic phonics instruction as a central piece in early reading learning: Direct Instruction (DI)4 and Open Court (OC).5 The third was a literature-based program, labeled Guided Reading (GR), wherein students were taught to use multiple strategies to focus on the meaning of what they read. This program was an adaptation of work by Irene Fountas and Gay Su Pinnell.6 The 84 students in our study live in urban settings and are of low socioeconomic status, but they are not coded for special education or for receiving ESL (English as a Second Language) services. To study the reading processes of these students, we asked the second-graders to read books to us aloud. We studied their reading using miscue analysis, an established research tool that analyzes oral reading miscues or divergences from the text to reveal a reader's use of phonics cues, language structure cues, and meaning-based cues.7 Thus we learned about the students' reading strategies, as well as their skill in comprehending as they read. …

Frugivores at a fruiting Ficus in south-eastern Peru

In neotropical forests, 50–90% of the canopy trees bear fruits adapted for animal dispersal whereas close to 100% of the shrubs and sub-canopy trees produce fleshy fruits (Howe & Smallwood 1982). It has been suggested that during periods of fruit scarcity, some plant species perform a critical role in the forest ecosystem by sustaining frugivorous animals that are important dispersal agents for seeds of many other trees during other seasons of the year (Howe 1984, Terborgh 1986a). Loss or absence of those seed dispersers would have strong negative consequences for tree species, thereby affecting the health of the entire ecosystem, over time. For that reason, plant species that sustain frugivores (= seed dispersers) during periods of resource scarcity have been called ‘keystone species’ (Gilbert 1980, Howe 1984, Terborgh 1983, 1986a, b; van Schaik et al. 1993). For example, in the tropical rain forest of Manu National Park, Peru, Terborgh (1983) found that figs, palm nuts and nectar are resources of great importance for the primate community during periods of fruit scarcity. During that season, three species of fig were identified as keystone resources maintaining nearly 40% of the animal biomass in the ecosystem (Terborgh 1983).