Biodiversity conservation and agricultural sustainability: towards a new paradigm of 'ecoagriculture' landscapes

The dominant late twentieth century model of land use segregated agricultural production from areas managed for biodiversity conservation. This module is no longer adequate in much of the world. The Millennium Ecosystem Assessment confirmed that agriculture has dramatically increased its ecological footprint. Rural communities depend on key components of biodiversity and ecosystem services that are found in non-domestic habitats. Fortunately, agricultural landscapes can be designed and managed to host wild biodiversity of many types, with neutral or even positive effects on agricultural production and livelihoods. Innovative practitioners, scientists and indigenous land managers are adapting, designing and managing diverse types of 'ecoagriculture' landscapes to generate positive co-benefits for production, biodiversity and local people. We assess the potentials and limitations for successful conservation of biodiversity in productive agricultural landscapes, the feasibility of making such approaches financially viable, and the organizational, governance and policy frameworks needed to enable ecoagriculture planning and implementation at a globally significant scale. We conclude that effectively conserving wild biodiversity in agricultural landscapes will require increased research, policy coordination and strategic support to agricultural communities and conservationists.     

Managing rock outcrops to improve biodiversity conservation in Australian agricultural landscapes

Summary  Rocky outcrops are prominent geological features in agricultural landscapes worldwide. Reptiles are a major component of these habitats and some species are restricted to, and more abundant on, rocky outcrops than in remnant vegetation. Rock outcrops are important to reptiles because they provide resources that are often limited in the surrounding landscape (e.g. micro-gradients in climatic conditions, basking- and retreat-sites). However, there is a knowledge gap in the literature addressing the conservation value of small, rocky outcrops. Management may be necessary to reverse habitat degradation in these systems. We identify four key areas of management that need to be addressed to improve outcrop habitat values and enhance biodiversity conservation in agricultural landscapes. Specific actions involve: (i) protecting outcrops from processes that cause damage to rock microhabitat, (ii) monitoring and managing changes in vegetation structure to maintain thermally suitable environments, (iii) applying integrated pest animal control and (iv) improving matrix management to enhance inselberg function and landscape connectivity. Further research is required to evaluate the efficacy of different management regimes on outcrop biota. We hope this paper will provide the stimulus for land managers to incorporate rocky outcrops in future biodiversity conservation programmes.     

Biodiversity conservation in cocoa production landscapes: an overview

Cocoa agroforests that retain a floristically diverse and structurally complex shade canopy have the potential to harbour significant levels of biodiversity, yet few studies have documented the plant and animal species occurring within these systems or within landscapes dominated by cocoa production. In this special issue, we bring together nine studies from Latin America, Africa and Asia that document the contribution of cocoa agroforestry systems to biodiversity conservation, and explore how the design, management and location of these systems within the broader landscape influence their value as habitats, resources and biological corridors. Tree diversity within the cocoa production systems is variable, depending on management, cultural differences, location and farm history, among other factors. Animal diversity is typically highest in those cocoa agroforests that have high plant diversity, structurally complex canopies, and abundant surrounding forest cover. In general, both plant and animal diversity within cocoa agroforests is greater than those of other agricultural land uses, but lower than in the original forest habitat. There are several emerging threats to biodiversity conservation within cocoa production landscapes, including the loss of remaining forest cover, the simplification of cocoa shade canopies and the conversion of cocoa agroforestry systems to other agricultural land uses with lower biodiversity value. To counter these threats and conserve biodiversity over the long-term, land management should focus on conserving native forest habitat within cocoa production landscapes, maintaining or restoring floristically diverse and structurally complex shade canopies within cocoa agroforests, and retaining other types of on-farm tree cover to enhance landscape connectivity and habitat availability.     

Effect of gap size and age on climber abundance and diversity in Budongo Forest Reserve, Uganda

A study of the effects of gap size and age on climber abundance and diversity was carried out in Budongo Forest Reserve in Uganda. Data were collected from compartments N5, W21, B1 and B3. Stump records were used to locate and estimate the ages of 78 gaps. Sample plots 5 × 5 m were set up in the gaps to assess climber abundance and diversity.
Climbers were more abundant and diverse in gaps that were more than 400 m², 15 months old and had more than 25% canopy opening. Momordica foetida was the most abundant climber species occurring on stems, branches and crowns of seedlings and saplings. Therefore, in order to keep natural regeneration free from climber tangles and produce good quality timber, climber control should be a major activity in tropical high forest management.     

Forest fragmentation effects on palm diversity in central Amazonia

1 The effects of fragmentation on quantitative measures of floristic diversity in a palm community were examined in the Biological Dynamics of Forest Fragments study area in central Amazonia. Three 1-ha, three 10-ha, two 100-ha and three continuous forest reserves, distributed among three sites, were surveyed. In each reserve, 10 20 × 20 m plots were sampled, resulting in a total of 110 plots representing 4.4 sampled hectares.
2 The taxon composition of this palm community was dominated by stemmed, understorey palms. A total of 23 225 individuals from 36 taxa was recorded; five of the taxa were not sampled in continuous forest.
3 Taxa richness did not vary across reserve size or sites unless taxa not sampled in the continuous forest were removed from the analysis. Smaller forest fragments then harboured fewer taxa in the seedling stage than large forest fragments or continuous forest, despite the short time since isolation (10–15 years). There was a significant effect of location on the number of taxa per plot for all life stages, but only seedling and total were significantly affected by reserve size.
4 Reserve size did not affect the Shannon and Evenness indices. Reserves of similar sizes were floristically more similar than reserves of very different sizes.
5 Palms are important for the structure and composition of the forest. Their conservation may require the establishment of a number of large reserves.     

Coping with Forest Fragmentation: The Primates of Kibale National Park,Uganda

A goal of conservation biology is to determine which types of species are most susceptible to habitat disturbance and which types of disturbed habitats can support particular species. We studied 20 forest fragments outside of Kibale National Park, Uganda, to address this question. At each patch, we determined the presence of primate species, tree species composition, patch size, and distance to nearest patch. We collected demographic, behavioral, and dietary data for Abyssinian black-and-white colobus (Colobus guereza). Black-and-white colobus and red-tailed guenons (Cercopithecus ascanius) were in almost all fragments; Pennant's red colobus (Procolobus pennantii) and chimpanzees (Pan troglodytes) were in some fragments; and blue monkeys (Cercopithecus mitis) and gray-cheeked mangabeys (Lophocebus albigena) were absent from all fragments. No species characteristics—home range, body size, group size, or degree of frugivory—predicted the ability of species to live in patches. No characteristics of patches—area, distance to the nearest patch, distance to Kibale, or number of food trees present—predicted the presence of a particular species in a patch, but distance to Kibale may have influenced presence of red colobus. Black-and-white colobus group size was significantly smaller in the forest patches than in the continuous forest of Kibale. For a group of black-and-white colobus in one patch, food plant species and home range size were very different from those of a group within Kibale. However, their activity budget and plant parts eaten were quite similar to those of the Kibale group. The lack of strong predictive variables as well as differences between other studies of fragmentation and ours caution against making generalizations about primate responses to fragmentation.     

Population Declines of Colobus in Western Uganda and Conservation Value of Forest Fragments

The processes of habitat loss and fragmentation are probably the most important threats to biodiversity. It is critical that we understand the conservation value of fragments, because they may represent opportunities to make important conservation gains, particularly for species whose ranges are not in a protected area. However, our ability to understand the value of fragments for primates is limited by the fact that researchers have conducted many studies in protected areas, which do not represent most fragments, and studies are typically short term. Here we determine the long-term survival probability of red (Procolobus pennantii) and black-and-white colobus (Colobus guereza) inhabiting forest fragments outside of Kibale National Park, Uganda. Local communities use the fragments primarily for subsistence agriculture and fuelwood. We surveyed primate populations 3 times over 8 yr, made a total inventory of all trees 2 times, contrasted behavior of groups inhabiting 1 fragment with groups in the continuous forest, and judged the conservation value of the fragments by quantifying patterns of forest use by local people. Of the 20 fragments surveyed, 16 supported resident populations of colobus in 1995, 2 were cleared in 2000, and an additional 2 fragments were cleared by 2003. In 1995 we counted 165 black-and-white colobus, whereas in 2000 and 2003, we counted 119 and 75 individuals, respectively. Seven fragments supported red colobus in 1995, 11 in 2000, and 9 in 2003. In 2000 we counted 159 red colobus, while in 2003, we saw 145 individuals. For both species, activity patterns in continuous forest were similar to those in a fragment, with the exception that individuals in the fragment rested more. Colobus in the fragment ate more mature leaves than colobus in the continuous forest did. Fragments supported all the fuelwood needs of an average of 32 people who lived immediately adjacent to them, and partially supported families up to 3 farms away (ca. 400 m), representing 576 people. Intensive harvesting for fuelwood occurred when neighboring households engaged in beer brewing (an average of 9.6% of the households), gin distilling (8.8%), or charcoal production (14.5%). Overall, between 2000 and 2003, the average density of trees declined by 14 trees/ha (range = 0–60 trees/ha). If current rates of clearing continue, the probability that the fragments will continue to support colobus populations is low.     

Tree fruiting phenology in Kalinzu Forest, Uganda

The spatial and temporal variations in species composition and abundance of trees that fruited in mechanically logged, intensively pit‐sawn and essentially undisturbed forest areas in Kalinzu Forest (0°17′S, 0°30′S and 30°00′, 30°07′E) were assessed. The duration and frequency of fruiting episodes of selected pioneer, understorey and canopy tree species were also determined. These phenology aspects were monitored for 18 months (between February 1997 and July 1998) in 99 plots, each 20 m × 20 m in size. Eighty species consisting of 1489 trees fruited during the study. Most of the species were recorded in the undisturbed forest area and least in the mechanically logged areas. Monthly number of individuals and species that fruited in each forest condition were significantly related to monthly rainfall. Two pioneer species (Musanga leo‐errerae and Trema orientalis), one sub‐canopy (Funtumia africana) and canopy (Parinari excelsa) species had extended fruiting phases (>5 months). Two understorey species (Oxyancius speciosus and Tabernaemontana spp.) had an extended phase while the third (Teclea nobilis) had a short (≤5 months) fruiting phase. Of the selected species, only Strombosia scheffleri (a sub‐canopy species) and P. excelsa had more than one fruiting episode.     

The diet of chimpanzees in the Budongo Forest Reserve, Uganda

Chimpanzee diets are highly variable, but in all cases dominated by ripe fruit. Previous work has suggested that in the Budongo Forest Reserve, Uganda, ripe fruit remains available throughout the year, but dietary data for chimpanzees at this site remain sparse. This paper details the diet of a recently habituated community of Budongo chimpanzees living in the Sonso region. Chimpanzees of this community spent 64.5% of their feeding time eating fruit, and 19.7% eating arboreal leaves. Terrestrial herbaceous vegetation formed only a minor component of the diet. In these general dietary characteristics, Budongo chimpanzees show greater similarity to those of the Gombe National Park than they do to those in the geographically closer and floristically more similar Kibale Forest National Park. The diet was dominated by the fruit of four species and leaves of two species, although the composition of the diet varied from month to month, remaining diverse. Figs were consumed throughout much of the year, and in consequence, should perhaps be regarded as a staple, rather than fallback, food. A period of food scarcity was not apparent in this study and future comparative nutritional investigation will be required to determine whether these chimpanzees face a time of dietary hardship.     

Crop raiding around Lake Mburo National Park, Uganda

In areas around Lake Mburo National Park, large wild animals wander in close proximity to human settlements. This poses serious conflict in terms of crop damage. The integration of conservation with other land uses is difficult where densely settled agricultural land surrounds a protected area potentially containing problem animals, as is the case for several parks in Africa and Asia. The intensity of crop raiding was quantified through the use of random crop quadrants/plots and area estimation techniques in a portion of raided fields. The animal species concerned were documented from observations, footprints and any other marks left behind. Three variables were tested as predictors of damage: human population density, distance from the park boundary and season. In this study, data is presented regarding crop loss in the different seasons of the year, analysis of crop damage variation and animal species involved in crop loss. A diverse assemblage of animals foraged on subsistence crops and analysis of crop damage revealed significant crop depreciation by wildlife.     

Censusing chimpanzees in the Budongo Forest,Uganda

It is difficult to make valid comparisons of chimpanzee densities among sites because observers calculate them using different methods. We argue that nest count estimates of density are preferable to densities from home range estimates because of the problems of defining home range. There are many problems associated with nest count methods, some of which have not been addressed in previous studies. In 1992, we censused chimpanzees in the Budongo Forest using three methods;the standing crop nest count (SCNC), the marked nest count (MNC), and visual sightings of the animals (VS). Each method is based on standard line transect techniques. Of 96 nests monitored for decay rate,those constructed in the dry seasons decayed faster than those in the wet seasons. All- day follows of individual chimpanzees and observations of nesting chimpanzees at dusk showed that about 15.8% of night nests were reused,17.5% of the population did not build nests, and 18.8% of nests were first constructed as day nests. Given the variability in nest decay rates, we argue that MNC is a better method than SCNC because it avoids having to calculate decay rates.     

Sustainable use of tropical forests by reduced-impact logging in Deramakot Forest Reserve,Sabah, Malaysia

In pursuance of economic growth and development, logging has exhausted the natural timber resource in the tropical rainforest of Sabah, Malaysia. Realizing the forest depletion, the Sabah Forestry Department, with technical support from the German Agency for Technical Cooperation, begun developing a management system with the intent of managing all commercial forest reserves in a way that mimics natural processes for sustainable production of low volume, high quality, and high priced timber products in 1989. As dictated by a forest management plan based on forest zoning, about 51,000 ha of the entire area is set aside for log production and 4,000 ha for conservation in Deramakot Forest Reserve, Sabah, Malaysia. This Forest Management Plan has served as the blueprint for operational work and biodiversity conservation in Deramakot to the present. A strict protection area is set aside for biodiversity conservation within the reserve. A reduced-impact logging system is being employed for harvesting with minimal impacts on the physical environment. Deramakot Forest Reserve was certified as “well managed” by an international certification body, the Forest Stewardship Council, in 1997 and is the first natural forest reserve in Southeast Asia managed in accordance with sustainable forestry principles. In addition to providing a "green premium," certification provides easier market access, evidence of legality, multi-stakeholder participation, conservation of biodiversity and best forest management practices, particularly reduced-impact logging techniques. Deramakot Forest Reserve is the flagship of the Sabah Forestry Department and serves as a symbol of what can be achieved with political support and institutional commitment.     

Patterns of bee diversity in mosaic agricultural landscapes of central Uganda: implication of pollination services conservation for food security

Little is known about bee communities and pollination services conservation strategies in sub-Sahara Africa. A study was conducted at 26 different sites with varying local landscape characteristics in farmlands of central Uganda in 2006. Bees were sampled using coloured pantraps, handnet and line transect counts. Overall 80,883 bee individuals from 6 families and 652 species were encountered. The bee fauna was characterized by a lower diversity of Melittidae and Andrenidae and a high diversity of Apidae, Megachilidae and Halictidae. Megachile and Lasioglossum were the two most species-rich genera. The most abundant species was Apis mellifera adansonii Linnaeus (23 % of total individuals) followed by Hypotrigona gribodoi Magretti (19 %), Meliponula ferruginea Lepeletier (13 %), Lasioglossum ugandicum Cockerell (7 %), Apis mellifera scutellata Latreille (6 %), Allodapula acutigera Cockerell (6 %), Ceratina rufigastra Cockerell (5 %), Ceratina tanganyicensis Strand (5 %), Braunsapis angolensis Cockerell (5 %), Megachile rufipes Fabricius (5 %), Meliponula bocandei Spinola (5 %) and Seladonia jucundus Smith (5 %). The mean number of species recorded per study site per day ranged between 14 and 49, whereas the abundance ranged between 188 and 1,859 individuals. Study sites in areas with intense land-use had species-poor bee communities compared to sites with medium to low land-use intensities. Study sites with riparian forest fragments and wetlands, or with forest fallows in their vicinity had significantly (P < 0.05) higher species richness and diversity than sites dominated by small-scale monoculture/polyculture fields or sites dominated by either simple or complex traditional agroforestry systems. An ordination analysis also revealed that bee communities were significantly (P < 0.01) influenced by the presence of semi-natural habitats (woodlands, fallows) and forest fragments in the surrounding of fields. Thus, natural and semi-natural habitats are of great value for afrotropical farmland bee communities. There is a need to put in place strategies and policies for semi-natural and forest fragments preservation for spatio-temporal stability of pollination services in rural landscapes. Farmers are recommended to increase on-farm trees cover to safeguard and enhance pollination function and services in fields. Mimicking natural vegetation through promoting establishment of forest plantations and village community forestry in rural landscapes is also critical for conserving pollination services.     

加强森林经营,实现森林保护与木材供应双赢

中国森林目前面临木材自给和生态安全的严重挑战.我国用1.2×108 hm2耕地养活了13亿人口,能否用2×108 hm2森林提供13亿人的用材,实现木材基本自给和森林保护的"双赢"?本文在分析我国林业的基本形势和实现木材自给必要性的基础上,从生产潜力和技术方面论证了实现木材自给和生态服务双赢的可能性.认为只要坚持以"森林经营"为核心,以培育稳定健康的森林生态系统为目标,以模拟森林的自然过程为手段重建森林生态系统,科学编制和执行森林经营规划,并加强林区基础建设和完善相应的林业政策,中国完全有可能实现生态保护与木材自给的"双赢".     

Tree diversity and distribution in undisturbed and human-impacted sites of tropical wet evergreen forest in southern Western Ghats, India

The composition, abundance, population structure and distribution patterns of all woody species ( 30 cm gbh) were investigated in an undisturbed and two adjacent human-impacted sites of a tropical wet evergreen forest in Kalakad National Park, Western Ghats, south India. Three 1-ha plots were established, one each in (i) an undisturbed site (named site UD), (ii) in a site selectively felled 35 years ago (site SF – small stems felled leaving the large trees (as shade) for developing it into a cardamom estate, on the failure of which the site was abandoned) and (iii) a frequently disturbed site (site FD – round woods logged for use in ovens for curing cardamom). These sites are 1 to 3 km apart in the same wet evergreen forest. In the three study plots a total of 2150 stems (mean density 716 ha^–1) covering 122 species in 89 genera and 41 families were enumerated. Species richness was greatest (85 species ha^–1) in the undisturbed site UD, intermediate (83) in SF and lowest (80) in FD. Tree density was greatest (855 stems ha^–1) in site SF, intermediate (720) in UD and lowest (575) in FD. The forest stand was exceptionally voluminous in site UD (basal area 94.64 m² ha^–1), intermediate (66.9 m²) in SF and least (61.7 m²) in FD, due to tree removal for fuel in the latter sites. Species composition and abundance patterns markedly varied between the three sites. In UD and SF, primary forest species (Cryptocarya bourdillonii , Cullenia exarillata Myristica dactyloides etc.) occurred in greater density. In FD heliophilic secondary forest species (Elaeocarpus venustus, Litsea wightiana, Viburnum punctatum and Vitex altissima) were abundant, while these were absent in UD and SF. The species–area curve did not reach an asymptote in any of the sites on the 1-ha scale. The stand population structure was clearly reverse J shaped in UD and SF, while small stems were 2- to 3-fold fewer in FD. Most trees exhibited clumped distribution of individuals on the 1-ha scale. Variation in the kind and richness of species and their abundance is related to human interference and the need for forest conservation is emphasized.