Native Species

Background / Purpose: The declining health of marine ecosystems around the world suggests that the current structure of sectoral governance is inadequate to successfully sustain human uses of the ocean and support healthy coastal and ocean ecosystems. One possible solution to this problem is ecosystem-based marine spatial planning (EB-MSP), which aims to maintain sustainable uses, healthy ecosystems, and the delivery of ecosystem services. In order to achieve these goals, EB-MSP must be based on specific, measureable ecological principles that articulate scientifically recognized attributes of healthy, functioning ecosystems that can be incorporated into a decision-making framework. Main conclusion: We present recommendations based on a synthesis of previously suggested principles, along with recommendations generated by a group of twenty marine scientists with diverse backgrounds and perspectives on MSP. The four ecological principles – maintaining or restoring (1) native species d...

A literature survey identified 403 primary research publications that investigated the ecological effects of invasive alien insects and/or the mechanisms underlying these effects. The majority of these studies were published in the last 8 years and nearly two-thirds were carried out in North America. These publications concerned 72 invasive insect species, of which two ant species, Solenopsis invicta and Linepithema humile, accounted for 18% and 14% of the studies, respectively. Most publications investigated effects on native biodiversity at population or community level. Genetic effects and, to a lesser extent, effects on ecosystem services and processes were rarely explored. We review the effects caused by different insect invaders according to: their ecosystem roles, i.e. herbivores, predators, parasites, parasitoids and pollinators; the level of biological organisation at which they occur; and the direct and indirect mechanisms underlying these effects. The best documented effects occur in invasive ants, Eurasian forest herbivores invasive in North America, and honeybees. Impacts may occur through simple trophic interactions such as herbivory, predation or parasitism. Alien species may also affect native species and communities through more complex mechanisms such as competition for resources, disease transmission, apparent competition, or pollination disruption, among others. Finally, some invasive insects, particularly forest herbivores and ants, are known to affect ecosystem processes through cascading effects. We identify biases and gaps in our knowledge of ecological effects of invasive insects and suggest further opportunities for research.

We review direct and indirect impacts of invasive alien species (focussing on plants and insects) on native bees worldwide. Although there is a rapidly growing body of research into the effects of invasive alien plants on native plant pollination via disruption of native mutualisms, there has been little research on the impacts of invasive alien plants directly on bees. Such impacts are likely to vary according to the taxon of plant, the functional specificity of the native bees, and ecosystem context. Conversely, there have been more attempts to document impacts of invasive alien social bees on native bees. Most of these studies only indirectly evaluate competition for resources, have focused on a few native species and findings are sometimes contradictory. However, some studies showed strong negative impacts, suggesting that effects might be species-specific. Additionally, pathogen spillover and reproductive disruption due to interspecific mating has been demonstrated among some closely related taxa. Where we lack unequivocal evidence for impacts however, this should not be interpreted as lack of effect. We recommend that future studies are robustly designed and consider impacts on genetic, species (particularly solitary bees) and ecosystem biodiversity.

The effect of urbanization can be immense, yet our understanding is rudimentary. Here, we compile the most recent information on urban impacts on avian populations and communities. Compared to other vertebrates, birds are easily monitored by skilled observers and provide a mechanism to explore urban effects and responses to different urban designs. Taxonomically, bird communities in distinctly different habitats are most different in the least disturbed sites and the most similar in the most urbanized sites. Urbanization tends to select for omnivorous, granivorous, and cavity nesting species. Increased urbanization typically leads to an increase in avian biomass but a reduction in richness. Unlike most passerines, raptors may have home ranges that extend beyond the urban boundary and therefore do not need to meet all their ecological requirements within urban areas. Urban habitats are often of superior quality to raptors because there they are often free from persecution and have an adequate food supply. The processes that underlie the patterns of population and community level responses need more attention, but several areas of have been identified as being important. Birds respond to vegetation composition and structure, and urban areas that retain native vegetative characteristics retain more native species than those that do not. Avian fecundity in urban areas is a reflection of species-specific adaptability to urban resources, and to levels of nest predation and nest parasitism. Additionally, non-consumptive human activities that increase with urbanization are recognized as having negative impacts on avian populations and communities. Avian survivorship in urban areas is influenced by risk of collision with man-made objects, changes in the predator assemblage, food supply, and disease. Missing are thorough investigations in the regions of highest human population growth, e.g. Southeast Asia. Additionally, there is a paucity of information from regions of high avian diversity, e.g. tropical forests. Clearly, local knowledge and study is required before implementation of management policies to reduce urban impacts on bird communities. Hopefully, such policies will include long-term monitoring. Demographic parameters of fecundity and survivorship need to be examined in conjunction with measures of community diversity and density across the urban gradient to better understand the quality of different urban habitats, and the variation of quality among spatial patterns of urbanization within the native habitat matrix.

The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for ...

Anthropogenic influences on the biosphere since the advent of the industrial age are increasingly causing global changes. Climatic change and the rising concentration of greenhouse gases in the atmosphere are ranking high in scientific and public agendas, and other components of global change are also frequently addressed, among which are the introductions of non indigenous species (NIS) in biogeographic regions well separated from the donor region, often followed by spectacular invasions. In the marine environment, both climatic change and spread of alien species have been studied extensively; this review is aimed at examining the main responses of ecosystems to climatic change, taking into account the increasing importance of biological invasions.

The primary hypothesis for the astonishing success of many exotics as community invaders relative to their importance in their native communities is that they have escaped the natural enemies that control their population growth -the 'natural enemies hypothesis'. However, the frequent failure of introduced biocontrols, weak consumer effects on the growth and reproduction of some invaders, and the lack of consistent strong top-down regulation in many natural ecological systems indicate that other mechanisms must be involved in the success of some exotic plants. One mechanism may be the release by the invader of chemical compounds that have harmful effects on the members of the recipient plant community (i.e., allelopathy). Here, we provide an abbreviated compilation of evidence for allelopathy in general, present a detailed case study for Centaurea diffusa, an invasive Eurasian forb in western North America, and review general evidence for allelopathic effects of invasive plants in native communities. The primary rationale for considering allelopathy as a mechanism for the success of invaders is based on two premises. First, invaders often establish virtual monocultures where diverse communities once flourished, a phenomenon unusual in natural communities. Second, allelopathy may be more important in recipient than in origin communities because the former are more likely to be naïve to the chemicals possessed by newly arrived species. Indeed, results from experiments on C. diffusa suggest that this invader produces chemicals that long-term and familiar Eurasian neighbors have adapted to, but that C. diffusa's new North American neighbors have not. A large number of early studies demonstrated strong potential allelopathic effects of exotic invasive plants; however, most of this work rests on controversial methodology. Nevertheless, during the last 15 years, methodological approaches have improved. Allelopathic effects have been tested on native species, allelochemicals have been tested in varying resource conditions, models have been used to estimate comparisons of resource and allelopathic effects, and experimental techniques have been used to ameliorate chemical effects. We do not recommend allelopathy as a 'unifying theory' for plant interactions, nor do we espouse the view that allelopathy is the dominant way that plants interact, but we argue that non-resource mechanisms should be returned to the discussion table as a potential mechanism for explaining the remarkable success of some invasive species. Ecologists should consider the possibility that resource and non-resource mechanisms may work simultaneously, but vary in their relative importance depending on the ecological context in which they are studied. One such context might be exotic plant invasion.

Globalization of trade and travel has facilitated the spread of non-native species across the earth. A proportion of these species become established and cause serious environmental, economic, and human health impacts. These species are referred to as invasive, and are now recognized as one of the major drivers of biodiversity change across the globe. As a long-time centre for trade, Europe has seen the introduction and subsequent establishment of at least several thousand non-native species. These range in taxonomy from viruses and bacteria to fungi, plants, and animals. Although invasive species cause major negative impacts across all regions of Europe, they also offer scientists the opportunity to develop and test theory about how species enter and leave communities, how nonnative and native species interact with each other, and how different types of species affect ecosystem functions. For these reasons, there has been recent growth in the field of invasion biology as scientists work to understand the process of invasion, the changes that invasive species cause to their recipient ecosystems, and the ways that the problems of invasive species can be reduced. This review covers the process and drivers of species invasions in Europe, the socio-economic factors that make some regions particularly strongly invaded, and the ecological factors that make some species particularly invasive. We describe the impacts of invasive species in Europe, the difficulties involved in reducing these impacts, and explain the policy options currently being considered. We outline the reasons that invasive species create unique policy challenges, and suggest some rules of thumb for designing and implementing management programs. If new management programs are not enacted in Europe, it is inevitable that more invasive species will arrive, and that the total economic, environmental, and human health impacts from these species will continue to grow.

The future of mammalian diversity in the tropics depends largely on the conservation value of human-dominated lands. We investigated the distribution of non-flying mammals in five habitats of southern Costa Rica: relatively extensive forest (227 ha), coffee plantation, pasture, coffee with adjacent forest remnant (<35 ha), and pasture with adjacent forest remnant (<35 ha). Of the 26 native species recorded in our study plots, 9 (35%) were restricted to forest habitat, 14 (54%) occurred in both forest and agricultural habitats, and 3 (11%) were found only in agricultural habitats. Species richness and composition varied significantly with habitat type but not with distance from the extensive forest. Interestingly, small forest remnants (<35 ha) contiguous with coffee plantations did not differ from more extensive forest in species richness and were richer than other agricultural habitat types. Small remnants contiguous with pasture were species-poor. When clearing started, the study region likely supported about 60 species. Since then, at least 6 species (10%), one family (4%), and one order (11%) have gone extinct locally. The species that disappeared were the largest in their families and included carnivorous (e.g., jaguar [Panthera onca]), herbivorous (e.g., Baird's tapir, [Tapirus bairdii]), and arboreal (e.g., mantled howler monkey [Alouatta palliata]) species. Although there is no substitute for native forest habitat, the majority of native, nonflying mammal species use countryside habitats. The populations of many persist even >5 km from relatively extensive forest, at least over the 40 years since forest clearance. Moreover, if hunting ceased, we expect that at least one of the locally extinct species could be reestablished in the existing landscape. Thus, there is an important opportunity to maintain and restore the diversity, abundance, and ecosystem roles of mammals in at least some human-dominated regions of the Neotropics. Biogeografía del Campo de Mamíferos Neotropicales: Oportunidades de Conservación en Paisajes Agrícolas de Costa Rica Resumen: El futuro de la diversidad de mamíferos en los trópicos depende principalmente del valor de la conservación de tierras dominadas por actividades humanos. Investigamos la distribución de mamíferos no voladores en cinco hábitats del sur de Costa Rica: selva relativamente extensa (227 ha), plantaciones de café, pastizal, café con remanente de selva adyacente (<35 ha) y pastizal con remanente de bosque adyacente (<35 ha). De las 26 especies nativas registradas en nuestras parcelas de estudio, 9 (35%) estaban restringidas al hábitat de bosque, 14 (54%) ocurrieron tanto en hábitats de bosque como agrícolas, y 3 (11%) solo se encontraron en hábitats agrícolas. La riqueza y composición de especies varió significativamente con el tipo de hábitat pero no con la distancia al bosque extenso. Lo interesante es que las, los remanentes pequeños de §Current address: Daily et al. Countryside Biogeography of Mammals 1815 bosque (<35 ha) contiguos a plantaciones de café no difirieron del bosque extenso en riqueza de especies y fueron más ricos que otros tipos de hábitat agrícolas. Los remanentes pequeños contiguos a pastizales fueron pobres en especies. Cuando comenzó la deforestación, la zona de estudio probablemente mantenía unas 60 especies. Desde entonces, por lo menos 6 especies (10%), una familia (4%) y un orden (11%) se han extinguido localmente. Las especies que desaparecieron fueron las mayores en sus familias e incluyeron especies carnívoras (por ejemplo, jaguar [Panthera onca]), herbívoras (por ejemplo, tapir, [Tapirus bairdii]) yárboricolas (por ejemplo, mono aullador [Alouatta palliata]). Aunque no hay sustituto para el hábitat de bosque nativo, la mayoría de las especies de mamíferos no voladores nativos utilizan hábitats rurales. Las poblaciones de muchas especies persisten aun a >5 km de bosque relativamente extenso, por lo menos en los 40 años desde la deforestación. Más aun, si cesara la cacería, esperamos que por lo menos una de las especies localmente extintas se reestablezca en el paisaje existente. Por lo tanto, hay una importante oportunidad para mantener y restaurar la diversidad, abundancia y papeles ecológicos de mamíferos en por lo menos algunas regiones dominadas por humanos en los neotrópicos.

Contrary to the popular notion that the advancing frontier of urban development has been swallowing and destroying natural ecosystems we present evidence that the sprawl of cities creates ample open space in peri-urban areas. Traditional view of city–nature dichotomy and clear spatial separation should be substituted by a vision that reflects the complex spatial dynamics of city–rural–natural fabric with extended areas of overlap among them. We present a survey of the relevant research concerning urban and ...

The introduction of alien species (AS) in marine environments is a factor of disturbance that can be viewed as a pollution agent. Using basic information on abundance and distribution of alien species, we developed an index that classifies AS impacts on native species, communities, habitats and ecosystem functioning. This method can be used to evaluate impact at five different levels of biopollution, fitting within the existing schemes for water quality assessment. Both spatial and temporal comparisons are possible. The assessments may also be used to evaluate management performance where avoidance measures were necessary and assist in preventing further unwanted introductions. Such assessments made for the same areas over time provide opportunities for measuring change in biopollution. We have tested the method using four different well-studied areas within the Baltic Sea (brackish to freshwater environments) for two different times, 20 years apart. Further developments of the scheme may be needed to cover some specific cases and taxonomic groups according to their life history.

Slash-and-burn agriculture (tavy) is the major cause of upland degradation and deforestation in eastern Madagascar. Upland degradation studies are largely based on floristic loss and have ignored the link to agriculture, the main activity on the uplands. The objectives were to analyze jointly with the Betsimisaraka farmers how slash-and-burn practices influence fallow species succession, and how current fallow/ cropping regimes influence agricultural productivity and upland degradation dynamics. The study was conducted in the Vohidrazana/ Beforona area, located at the margins of the Ankeniheny-Zahamena rainforest corridor. Semi-structured interviews were conducted in 9 villages resulting in 96 individual and 22 group interviews. These were complemented by 212 historical field plot inventories on 32 farms. The researchers' and farmers' knowledge systems were treated equally and complemented each other in the joint analysis. Over the last 30 years, fallow periods decreased from 8-15 years to 3-5 years. Hence, fallow vegetation is changing within 5-7 fallow/cropping cycles after deforestation from tree (Trema orientalis) to shrub (Psiadia altissima, Rubus moluccanus, Lantana camara) to herbaceous fallows (Imperata cylindrica and ferns) and grasslands (Aristida sp.), when land falls out of crop production. This sequence is 5-12 times faster than previously reported. The frequent use of fire is replacing native species with exotic, aggressive ones and favors grasses over woody species, creating treeless landscapes that are of minimal productive and ecological value. Unlike most discussions during the past 20-30 years that refer to fallow duration per se as a measure to soil recovery, our results show that fallow periods need to increase in length with each additional fallow/ cropping cycle after deforestation in order to restore the soils to a similar level of productivity. Already with the third cycle after deforestation, vegetation starts to degrade quickly in parallel with agricultural productivity decline. The Betsimisaraka's fallow knowledge is very rich. Fallows are characterized by species life form, species composition, vegetation appearance, cycles after deforestation, and agricultural potential. Distinct fallow types are easily identifiable in the field and inform on the critical threshold, below which soils are lost to farming. Clear management guidelines go along with each fallow type. We recommend upland agricultural intensification and diversification based on improved soil fertility through optimized organic and inorganic inputs and fire-less land management that encourages the re-establishment of nutrient stocks. If young farmers perceive a real opportunity in agricultural intensification, the migration towards the forest borders to pursue tavy might be halted. #

This study performs a meta-analysis of existing studies of European riparian forests to investigate which exotic species have successfully established in intact riparian forests and which characteristics of these forests correspond with successful establishment. We used analysis of covariance models to investigate the relationship between community species richness, percent exotic species, and several environmental variables. We found a total richness of 1380 species, of which 45 (3.3%) were exotic. Species-rich communities generally had the higher percentage of exotics, but were not significantly related to latitude or environmental variables. Exotics, in contrast, were at generally higher levels at lower latitudes and were more abundant in large river plains and communities with intermediate levels of disturbance. These results suggest that future climate change and human actions that mimic intermediate levels of disturbance may further enhance the spread of exotic species.

Large catchment basins may be viewed as ecosystems in which natural and cultural attributes interact. Contemporary river ecology emphasizes the four-dimensional nature of the river continuum and the propensity for riverine biodiversity and bioproduction to be largely controlled by habitat maintenance processes, such as cut and fill alluviation mediated by catchment water yield. Stream regulation reduces annual flow amplitude, increases baseflow variation and changes temperature, mass transport and other important biophysical patterns and attributes. As a result, ecological connectivity between upstream and downstream reaches and between channels, ground waters and floodplains may be severed. Native biodiversity and bioproduction usually are reduced or changed and non-native biota proliferate.

Species richness is decreasing at a global scale. At subglobal scales, that is, within any defined area less extensive than the globe, species richness will increase when the number of nonnative species becoming naturalized is greater than the number of native species becoming extinct. Determining whether this has occurred is usually difficult because detailed records of species extinctions and naturalizations are rare; these records often exist, however, for oceanic islands. Here we show that species richness on oceanic islands has remained relatively unchanged for land birds, with the number of naturalizations being roughly equal to the number of extinctions, and has increased dramatically for vascular plants, with the number of naturalizations greatly exceeding the number of extinctions. In fact, for plants, the net number of species on islands has approximately doubled. We show further that these patterns are robust to differences in the history of human occupation of these isla...

Using 15 shade coffee farms and two forest reserves located in central Veracruz, Mexico, we evaluated how tree vegetation structure and richness changed as a function of management type and compared to that remnant forest fragments. Coffee farms were classified as shade monocultures (SMs), simple polycultures (SPs), or diverse polycultures (DPs). A total of 124 sampling units representing 15.19 ha were randomly located in farms with the number of sampling units varying as a function of farm area. Twenty additional plots were sampled in two nearby cloud forest fragments. Forest vegetation structure was higher than in farms, except for mean canopy height that was similar to that in SP and DP farms. Within farms, tree density was generally higher in SM, whereas basal area and both mean and maximum height were higher in SP and DP sites. We recorded 2833 individuals representing 107 tree species !5 cm dbh in coffee farms, including 24 non-native species, and 83 native species (33 primary, and 50 secondary tree species). Patterns of richness followed the expected pattern with 11 AE 1.4 (S.E.) tree species in SM farms, 14 AE 1.8 in SP farms, 29 AE 2.3 in DP farms, and 38 AE 16 in forest control sites; however, rarefaction strongly suggests that DP sites are actually richer in species than the forests studied. The proportion of native tree species in each coffee management type was consistently elevated (78%). Since the majority of species (71%) were rare and found only in one or two farms, complementarity among types of coffee management (68-77%), and coffee managements and forest (90-92%) was very high. SP and DP farms had the highest proportions of animal-dispersed species and were similar to forest. Species richness was positively correlated with tree density for DP, and to basal area for SM farms. Our results suggest that shade diversity is actively managed by coffee farmers and that all three types of coffee management studied may have an important role to play in the conservation of regional biodiversity. Considering factors such as complementarity, landscape heterogeneity, functional diversity, and the rigor of vegetation surveys may also help improve the validity, and thus the impact, of coffee certification programs designed with the goal of conserving tropical montane biodiversity. #

Historical fragmentation and a current annual deforestation rate of 1.2% in the Western Ghats biodiversity hotspot have resulted in a human-dominated landscape of plantations, agriculture, and developed areas, with embedded rainforest fragments that form biodiversity refuges and animal corridors. On private lands in the Anamalai hills, India, we established restoration sites within three rainforest fragments (5, 19, and 100 ha) representing varying levels of degradation such as open meadow, highly degraded sites with dense Lantana camara invasion, abandoned exotic tree plantations (Eucalyptus grandis and Maesopsis eminii), and sites with mixed-native and exotic tree canopy. Between 2000 and 2004, we planted annually during the southwest monsoon 7,538 nurseryraised seedlings of around 127 species in nine sites (0.15-1.0 ha). Seedlings monitored at 6-monthly intervals showed higher mortality over the dry season than the wet season and survival rates over a 2-year period of between 34.4 and 90.3% under different site conditions. Seedling survival was higher in sites with complete weed removal as against partial removal along planting lines and higher in open meadow and under shade than in sites that earlier had dense weed invasion. Of 44 species examined, survival across sites after 24 months for a majority of species (27 species, 61.4%) was higher than 50%. Retaining regenerating native species during weed clearing operations was crucial for rapid reestablishment of a first layer of canopy to shade out weeds and enhance survival of shade-tolerant rainforest seedlings.

Two genetically improved tilapia strains (GIFT and Akosombo) have been created with Oreochromis niloticus (Nile tilapia), which is native to Africa. In particular, GIFT has been shown to be significantly superior to local African tilapia strains in terms of growth rate. While development economists see the potential for food security and poverty reduction in Africa from culture of these new strains of tilapia, conservationists are wary of potential ecological and genetic impacts on receiving ecosystems and native stocks of tilapia. This study reviews the history of the GIFT technology, and identifies potential environmental and genetic risks of improved and farmed strains and tilapia in general. We also estimate the potential economic gains from the introduction of genetically improved strains in Africa, using Ghana as a case country. Employing a combination of the Economic-Surplus model and Monte Carlo simulation, we found the mean net present value (NPV) of the introduction of the GIFT strain in Ghana to be approximately 1% of the country's gross domestic product. Sensitivity analysis indicated that the difference in growth or yield between the GIFT and locally-available strains has the largest effect on mean NPV. We conclude that improvements in management practices and infrastructure could increase the yield and profitability of the local strains even if genetically-improved strains are not introduced. These improvements also will ensure the realization of the full potential of introduced strains.

Extensive cattle production currently occupies more than 27% of the rural landscapes in Latin America, and continues to expand. This activity, deeply rooted in the culture and rural economy of the region, requires an urgent transformation if it is to become both more efficient and environmentally friendly. Silvopastoral systems that incorporate native trees and shrubs are instrumental for the productive

Temporal trends in attributes of restored ecosystems have been described conceptually as restoration trajectories. Measures describing the maturity or ecological integrity of a restoration site are often assumed to follow monotonically increasing trajectories over time and to eventually reach an asymptote representative of a reference ecosystem. This assumption of simple, predictable restoration trajectories underpins federal and state policies in the United States that mandate wetland restoration as compensation for wetlands damaged during development. We evaluated the validity of this assumption by tracking changes in 11 indicators of floristic integrity, often used to determine legal compliance, in 29 mitigation wetlands. Each indicator was expressed as a percentile relative to the distribution of that indicator among .100 naturally occurring reference wetlands. Nonlinear regression was used to fit two alternative restoration trajectories to data from each site: an asymptotic (negative exponential) increase in the indicator over time and a peaked (double exponential) relationship. Depending on the particular indicator, between 48% and 76% of sites displayed trends that were at least moderately well described (R 2 . 0.5) by one of the two models. Floristic indicators based on species richness, including native richness, number of native genera, and the floristic quality index, rapidly increased to asymptotes exceeding levels in a majority of reference wetlands. In contrast, indicators based on species composition, including mean coefficient of conservatism and relative importance of perennial species, increased very slowly. Thus, some indicators of restoration progress followed increasing trajectories and achieved or surpassed levels equivalent to high-quality reference sites within five years, whereas others appeared destined to either not reach equivalency or to take much longer than mitigation wetlands are typically monitored. Finally, some indicators of restoration progress, such as relative importance of native species, often increased over the first five to 10 years and then declined, which would result in a misleading assessment of progress if based on typical time scales of monitoring. Therefore, the assumption of simple, rapid, and predictable restoration trajectories that underlies wetland mitigation policy is unrealistic.

Rewilding is a strategy for the conservation of complete, self-sustaining ecosystems, primarily involving the protection and, where necessary, reintroduction, of populations of keystone species in large, connected reserve networks. A potential method of preserving ecosystem functions and biodiversity, it is now receiving a great deal of practical and political attention, particularly in North America. In Scotland, where many native species

The introduction of hybrid varieties cocoa has led to the progressive disappearance of the complex agroforestry systems in Côte d’Ivoire. However in forests-savannah transition area, these systems seem to persist in despite the high frequency of bushfires, low rainfalls and the change of cocoa trees varieties. To understand the farming practices in that zone, data were collected in 68 cocoa farms located in three major cocoa producing in the sub-prefecture of Kokumbo. We used 105 plots of 0.0625 ha (25 m X 25 m) to characterize the botanical composition, structure, biophysical variation and management practices. In the 6.56 ha cocoa farm surveyed 2,149 stems belonging to 86 species and 36 families were encountered. The average species richness varied from 4 species to 6.4 per 625 m2 plot. The global density of associated plants was 227.3 trees/ha for a basal area of 24.1 m2 / ha. Results also showed significant differences in farmers’ practices which enabled us to distinguish three main cocoa agroforestry Systems (AFS): Simple AFS with open canopy and high density of plantain trees, characterized by the hybrid varieties; young complex AFS with high species diversity and opened canopy; and complex AFS with dense and closed canopy characterized Amelonado variety. These results highlight the strategy adopted by the farmers in the management of cocoa plantations in the zone of transition forest-savannah. Additional analyses must be done to assess their yield and the biomass.

The eects of biological invasions are most evident in isolated oceanic islands such as the Hawaiian Archipelago, where invasive plant species are rapidly changing the composition and function of plant communities. In this study, we compared the speci®c leaf area (SLA), leaf tissue construction cost (CC), leaf nutrient concentration, and net CO 2 assimilation (A) of 83 populations of 34 native and 30 invasive species spanning elevation and substrate age gradients on Mauna Loa volcano in the island of Hawaii. In this complex environmental matrix, where annual precipitation is higher than 1500 mm, we predicted that invasive species, as a group, will have leaf traits, such as higher SLA and A and lower leaf CC, which may result in more ecient capture of limiting resources (use more resources at a lower carbon cost) than native species. Overall, invasive species had higher SLA and A, and lower CC than native species, consistent with our prediction. SLA and foliar N and P were 22.5%, 30.5%, and 37.5% higher, respectively, in invasive species compared to native ones. Light-saturated photosynthesis was higher for invasive species (9.59 lmol m A2 s A1 ) than for native species (7.31 lmol m A2 s A1 ), and the dierence was larger when A was expressed on a mass basis. Leaf construction costs, on the other hand, were lower for the invasive species (1.33 equivalents of glucose g A1 ) than for native species (1.37). This dierence was larger when CC was expressed on an area basis. The trends in the above traits were maintained when groups of ecologically equivalent native and invasive species (i.e., sharing similar life history traits and growing in the same habitat) were compared. Foliar N and P were signi®cantly higher in invasive species across all growth forms. Higher N may partially explain the higher A of invasive species. Despite relatively high N, the photosynthetic nitrogen use eciency of invasive species was 15% higher than that of native species. These results suggest that invasive species may not only use resources more eciently than native species, but may potentially demonstrate higher growth rates, consistent with their rapid spread in isolated oceanic islands.

A faunal survey conducted along an elevational gradient in Balbalasang-Balbalan National Park in northern Luzon Island, Philippines, revealed 15 species of non-flying small mammals. Thirteen, including 1 shrew and 12 murid rodents, are native species endemic to the Philippines, 7 of which are endemic to northern Luzon. Two species are non-native murid rodents that were restricted to disturbed habitats. As seen elsewhere in the Philippines, species richness was greatest in montane and mossy forest habitats at mid to high elevations. Although species-rich, the Balbalasang gradient does not include the full diversity of species known from the Central Cordillera region. Comparative data from sites elsewhere on Luzon reveal that total species richness is a function of local elevation, with more species present in areas with higher mountain peaks. These patterns reflect the fact that diversity of non-flying small mammals is concentrated in highland areas where local assemblages include species that differ in diel activity, spatial habitat use, and diet. Numerically dominant species are members of a single murid clade, and several of these are specialized predators of earthworms. Similarly structured communities in the highlands of Mindanao include species that are only distantly related to those of Luzon. Community convergence is thought to reflect the influence of similar habitat structure, food resource availability, and trophic partitioning in shaping small mammal assemblages.

Forest ecosystems shelter a major part of terrestrial biological diversity, and over the past decades, conservation of biodiversity has become a key element in national forest policies and planning. Plantation forests are cultivated forest ecosystems established primarily for wood biomass production but also for soil and water conservation or wind protection. During the past decade, the global forest plantation area

Management of nonindigenous species is a crucial aspect of maintaining native biodiversity and normal ecosystem functions. We attempt to guide researchers in developing projects that will be of use to conservation practitioners, tangibly improving applied conservation measures. We advocate a directed approach for conservation research to aid in prioritizing nonindigenous species for intervention by resource managers. This approach includes outlining what needs to be known to make such relative judgments about the impacts of nonindigenous species and the most promising methods by which to obtain such information. We also address active measures that should be taken once priorities have been set, highlighting the roles of risk assessment and research in improving control efforts. Ultimately, a better match between research and practical conservation needs should result in more effective reduction of the effects of nonindigenous species on native species.

Among the nitrogen (N2)-fixing bacteria, the rhizobia in symbiosis with legumes are generally the most important in agriculture, although Frankia, cyanobacteria and heterotrophic free-living N~-fixers may fix significant amounts of nitrogen under specific conditions. The taxonomy of N2-fixing bacteria is undergoing substantial revisions due to the advent of molecular methods for phylogenetic analysis, and in certain cases this has proved useful in unravelling ecological relationships among confusing groups. Molecular methods are also proving useful in studies of biodiversity within populations of rhizobial species.

Pesticides used in banana production may enter watercourses and pose ecological risks for aquatic ecosystems. The occurrence and effects of pesticides in a stream draining a banana plantation was evaluated using chemical characterization, toxicity testing and macrobenthic community composition. All nematicides studied were detected in the surface waters of the banana plantation during application periods, with peak concentrations following applications. Toxicity tests were limited to the carbofuran application and no toxicity was observed with the acute tests used. However, since pesticide concentrations were generally below the lowest LC50 value for crustaceans but above calculated aquatic quality criteria, there remains a risk of chronic toxicity. Accurate ecological assessments of pesticide use in banana plantations are currently limited by the lack of local short-term chronic toxicity tests and tests using sensitive native species. Relatively constant levels of four pesticides (imazalil, thiabendazole, chlorpyrifos and propiconazole), which had toxic effects according to the 96h hydra and 21d daphnia chronic test, were recorded in the effluent of the packing plant throughout the study, indicating that the solid waste trap used in this facility was not effective in eliminating toxic chemicals. Certain taxa, such as Heterelmis sp. (Elmidae), Heteragrion sp. (Megapodagrionidae, Odonata), Caenis sp. (Caenidae, Ephemerotera), and Smicridea sp. (Hidropsychidae, Trichoptera), were more abundant at reference sites than in the banana farm waters, and may be good candidates for toxicity testing. Multivariate analyses of the macroinvertebrate communities clearly showed that the banana plantation sites were significantly different from the reference sites. Moreover, following the pesticide applications, all the banana plantation sites showed significant changes in community composition, with the same genera being affected at all sites and for all pesticides (terbufos, cadusafos and carbofuran). Consequently, the results presented here show that multivariate analysis of community composition was more sensitive in distinguishing pesticide effects than the toxicity tests and richness and composition measures used. We conclude that monitoring macroinvertebrate communities can be a powerful tool in the assessment of ecological effects of banana production.

Feral cats have been directly responsible for the extinction of numerous species on islands worldwide, including endemic species of mammals, birds and reptiles. The diet of feral cats in the main habitats of the Canary Islands, as generally occurred on oceanic islands, is mainly composed of introduced mammals, and native species of birds, reptiles and insects. The impact of feral cat upon the endangered species was assessed by evaluating their relative abundance in the cats’ diet and by considering their current conservation status. A total of 68 different preys were identified at species level in all studies carried out in the Canary Islands (5 mammals, 16 birds, 15 reptiles and 32 invertebrates). From all the species preyed by feral cats in the Canary Islands, only four of them are considered threatened by the IUCN Red List of Threatened Species: one endemic bird Saxicola dacotiae and three endemic giant lizards, Gallotia simonyi, Gallotia intermedia, and Gallotia gomerana. Although some efforts on management control have been carried out, it is necessary to enforce these conservation activities on those areas of Tenerife, La Gomera and El Hierro where giant lizards are still present. Furthermore some local areas where endangered bird species are highly predated should be protected. Nevertheless, it is important to take into account the presence of other introduced species such as rats, mice or rabbits in order to avoid problems derived from the hyperpredation process and mesopredator release effect.

The avifauna of New Zealand has been severely depleted since human colonisation and currently contains a disproportionately high number of threatened species. Of the 23 threatened shorebird species worldwide, six are endemic to New Zealand. We review the status of New Zealand's endemic shorebirds and examine the impact on them of various threats, particularly predation by introduced mammals. The conservation status of the 10 extant species (three oystercatchers, one stilt, four plovers and two snipe) is outlined and the factors that predisposed them to predation by introduced mammals are summarised. Individual species accounts are presented, including data on population trends, known or suspected impacts of predation, identi®cation of important predator species, other threats, and conservation measures currently in place or required. One species and two subspecies are extinct, three species are con®ned to predator-free islands and another is found only on the Chatham Islands group. Six survive on the mainland but three have declined to varying degrees and are assigned threatened status by . Only one plover and two oystercatchers are still relatively numerous and/or widespread. Rats, cats and mustelids have had the greatest overall impacts. Conservation measures in place to mitigate the eects of introduced predators include the formulation of recovery plans, predator control around breeding areas, captive breeding and rearing programmes and the founding of new populations by translocation. There are often substantial dierences in susceptibility to predation of closely related or ecologically similar taxa, and we stress the importance of basing conservation management decisions on relevant and detailed demographic and ecological studies. The main threat to threatened shorebirds elsewhere in the world is loss or degradation of habitat; the disproportionate impact of mammalian predators on New Zealand shorebirds is unusual but not unique. #

Patterns of native and alien plant diversity in response to disturbance were examined along an elevational gradient in blue oak savanna, chaparral, and coniferous forests. Total species richness, alien species richness, and alien cover declined with elevation, at scales from 1 to 1000 m 2 . We found no support for the hypothesis that community diversity inhibits alien invasion. At the 1-m 2 point scale, where we would expect competitive interactions between the largely herbaceous flora to be most intense, alien species richness as well as alien cover increased with increasing native species richness in all communities. This suggests that aliens are limited not by the number of native competitors, but by resources that affect establishment of both natives and aliens.