Drought and the consequences of El Niño in Borneo: a case study of figs

Borneo has a perhumid climate but occasional severe droughts have an important impact. Droughts may affect the composition and size structure of plant communities through differential mortality or, via their impact on the availability of plant resources, affect plant–animal interactions. From January to April 1998, northern Borneo suffered a very severe drought linked to the El Niño Southern Oscillation event of 1997–1998. In this article, the impacts of this drought on the rain forest at Lambir Hills National Park, Sarawak, are considered with special reference to a keystone plant group, the figs. Small fires entered the edge of the forest from the roadside, killing saplings, climbers, and understory trees. Community-wide mortality for adult trees was 0–7 times higher than in nondrought years, with larger trees showing a greater proportional increase. In figs, mortality was significantly higher in pioneers, but hemiepiphytes and roadside species were unaffected. Phenology was substantially affected. Leaf and flower/fruit production decreased or ceased during the drought and increased suddenly following renewed rain. Pollinators of dioecious figs became locally extinct during the drought, and other plant–animal interactions may also have been disrupted. The frequency and severity of droughts has increased substantially in the past three decades, and climate models suggest this may be the result of global warming. The impacts of the 1998 drought at Lambir Hills National Park suggest that, should this trend continue, a substantial alteration of habitats and overall loss of biodiversity can be expected in Borneo.     

Distribution of Fusarium wilt of Bambara nut (Vigna subterranea (L.) Verdc.) in farmers’ fields’ of Busia County in Western Kenya and its management using farmyard manure

A study was carried out to determine Fusarium wilt distribution in Bambara nut farmers’ fields and its management using farm yard manure (FYM). Four villages in Busia County were purposively sampled for the study. The data generated were subjected to analysis of variance and treatment means separated by least significant difference test. Fusarium wilt incidence in the fields ranged from 14.63 to 43.56%. In the greenhouse, FYM reduced the disease incidence by 10.2% and severity by 9.5% on the black landrace and 1.9 and 12.8%, respectively, on the red landrace. In the field, FYM reduced disease incidence by 9.1% and severity by 6.9% on the black landrace and 10.4 and 10.4%, respectively, on the red landrace. Farm yard manure had the lowest area under disease progress curve irrespective of the landrace. The study confirmed the presence of the pathogen in the fields and the ability to manage the disease using FYM.     

Carayonovus n. gen. from Reunion Island – aberrant new genus of Anthocoridae or representative of a new family (Heteroptera: Cimicoidea)?

Carayonovus insignis n. gen., n. sp., a remarkable new genus and species of Heteroptera, is described from Reunion Island. It is tentatively placed in the family Anthocoridae (Cimicoidea), but because of its remarkable sexual dimorphism and possession of characters not normally associated with this family or even with Cimicoidea, the genus is discussed in terms of the validity or otherwise of including it in these taxa. Its habitat preference is also examined.     

Área de Conservación Guanacaste,northwestern Costa Rica: Converting a tropical national park to conservation via biodevelopment

The ~30,000 hectare classical Costa Rican Parque Nacional Santa Rosa has used about 35 years and $107 million to be converted to the 169,000 ha government-NGO hybrid Área de Conservación Guanacaste (ACG). This semi-decentralized conservation entity has today a staff of ~150 paraprofessional resident Costa Ricans, biodeveloping at least 650,000 multicellular species (Eucaryotes) into perpetuity for ACG survival through being integrated with its local, regional, national, and international society. ACG began in 1985 as an ongoing exercise of landscape-level ecosystem rescue and restoration of a continuous swath from 6 km out in the Pacific ocean, across dry forested lowlands, up and over the volcanic Cordillera Guanacaste, and down into the rain-forested Caribbean lowlands. It is being impacted by climate change, yet its diverse ecosystems hold hope for major biodiversity survival, albeit in new community assemblages. It quickly became simultaneously a biophysical challenge and an administratively novel challenge in decentralized conservation in a democratic tropical country. ACG specializes at being managed by on-the-job stimulated and trained residents with minimal formal education, searching for ways to involve ACG in its society without damaging its wildness, and pioneering ways to render wild biodiversity to being a welcome member at society's negotiating table. It continues to pay its bills through government subsidy, generous donors, payments for services, project grants, and huge in-kind contributions from mutualisms. ACG hopes that the concept will spread south–south to other tropical countries while they still have some of their wild biodiversity with which to integrate.     

Modelling biomass of mountainous grasslands by including a species composition map

High mountain grasslands offer multiple goods and services to society but are severely threatened by improper land use practices such as abandonment or rapid intensification. In order to reduce abandonment and strengthen the common extensive agricultural practice a sustainable land use management of high mountain grasslands is needed. A spatially detailed yield assessment helps to identify possible meadows or, on the contrary, areas with a low carrying capacity in a region, making it easier to manage these sites. Such assessments are rarely available for remote and inaccessible areas. Remotely sensed vegetation indices are able to provide valuable information on grassland properties. These indices tend, however, to saturate for high biomass. This affects their applicability to assessments of high-yield grasslands.The main aim of this study was to model a spatially explicit grassland yield map and to test whether saturation issues can be tackled by consideration of plant species composition in the modelling process. The high mountain grassland of the subalpine belt (1800 – 2500 m a.s.l.) in the Kazbegi region, Greater Caucasus, Georgia, was chosen as test site for its strong species composition and yield gradients.We first modelled the species composition of the grassland described as metrically scaled gradients in the form of ordination axes by random forest regression. We then derived vegetation indices from Rapid Eye imagery, and topographic variables from a digital elevation model, which we used together with the multispectral bands as predictive variables. For comparison, we performed two yield models, one excluding the species composition maps and one including the species composition map as predictors. Moreover, we performed a third individual model, with species composition as predictors and a split dataset, to produce the final yield map.Three main grassland types were found in the vegetation analysis: Hordeum violaceum-meadows, Gentianella caucasea-grassland and Astragalus captiosus-grassland. The three random forest regression models for the ordination axes explained 64%, 33% and 46% of the variance in species composition. Independent validation of modelled ordination scores against a validation data set resulted in an R² of 0.64, 0.32 and 0.46 for the first, second and third axes, respectively. The model based on species composition resulted in a R² = 0.55, whereas the benchmark model showed weaker relationships between yield and the multispectral reflectance, vegetation indices, and topographical parameters (R² = 0.42). The final random forest yield model used to derive the yield map resulted in 62% variance explained and an R² = 0.64 between predicted and observed biomass. The results further indicate that high yields are generally difficult to predict with both models.The benefit of including a species composition map as a predictor variable for grassland yield lies in the preservation of ecologically meaningful features, especially the occurrence of high yielding vegetation type of Hordeum violaceum meadows is depicted accurately in the map. Even though we used a gradient based design, sharp boundaries or immediate changes in productivity were visible, especially in small structures such as arable fields or roads (Fig. 6b), making it a valuable tool for sustainable land use management. The saturation effect however, was mitigated by using species composition as predictor variables but is still present at high yields.     

Phenology of plants in relation to ambient environment in a subalpine forest of Uttarakhand,western Himalaya

Observations on phenology of some representative trees, shrubs, under-shrubs and herbs in a subalpine forest of Uttarakhand, western Himalaya were recorded. With the commencement of favorable growth season in April, occurrence of leaf fall was indicatory growth phenomenon in Quercus semecarpifolia, Q. floribunda and Abies spectabilis. However, active vegetative growth in herbaceous species starts onward April and fruit maturation and seed dehiscence are completed from mid of September to October. In general, vegetative growth and reproductive stages in majority of the studied species seems to be dependent on adequate moisture content and also flowering and fruiting in subalpine plants correlate ambient temperature.     

Endogenous Release of γ-Aminobutyric Acid from the Medial Preoptic Area Measured by Microdialysis in the Anaesthetised Rat

The characteristics of gamma-aminobutyric acid (GABA) release as monitored by microdialysis have been investigated in the chloral hydrate anaesthetised rat. The high outflow of GABA following insertion of the microdialysis probe (membrane 2 mm in length, 0.5 mm in diameter) into the medial preoptic area was found to decline to a stable baseline level after 2 h. After this time, perfusion with a medium containing 100 mM potassium ions evoked a 56-fold increase in GABA outflow. The addition of the calcium channel blocker verapamil (100 microM) to the perfusion medium induced significant 25 and 50% reductions in basal and potassium-stimulated GABA outflow, respectively. In the same animals, verapamil caused an 80% decrease in potassium-stimulated noradrenaline outflow. The glutamic acid decarboxylase inhibitors 3-mercaptopropionic acid and L-allylglycine added to the perfusion medium at a concentration of 10 mM reduced basal GABA release by approximately 50% with different time-courses of action. Ethanolamine-O-sulfate, a GABA-transaminase inhibitor, induced significant increases in basal GABA outflow 90 min after inclusion in the perfusion medium. These results demonstrate that microdialysis is a suitable technique with which to monitor extracellular levels of GABA and provide in vivo data on GABA release and degradation mechanisms.     

Demographic population structure of black howler monkeys in fragmented and continuous forest in Chiapas,Mexico: Implications for conservation

For wild primates, demography studies are increasingly recognized as necessary for assessing the viability of vulnerable populations experiencing rapid environmental change. In particular, anthropogenic changes such as habitat loss and fragmentation can cause ecological and behavioral changes in small, isolated populations, which may, over time, alter population density and demographic structure (age/sex classes and group composition) in fragment populations relative to continuous forest populations. We compared our study population of Endangered black howler monkeys (Alouatta pigra) in 34 forest fragments around Palenque National Park (PNP), Mexico (62 groups, 407 individuals), to the adjacent population in PNP, protected primary forest (21 groups, 134 individuals), and to previous research on black howlers in fragments in our study area (18 groups, 115 individuals). We used χ² and Mann–Whitney U tests to address the questions: (a) what is the current black howler demographic population structure in unprotected forest fragments around PNP? (b) How does it compare to PNP's stable, continuous population? (c) How has it changed over time? Compared to the PNP population, the fragment populations showed higher density, a significantly lower proportion of multimale groups, and significantly fewer adult males per group. The population's age/sex structure in the fragmented landscape has been stable over the last 17 years, but differed in a higher proportion of multifemale groups, higher density, and higher patch occupancy in the present. In the context of conservation, some of our results may be positive as they indicate possible population growth over time. However, long-term scarcity of adult males in fragments and associated effects on population demographic structure might be cause for concern, in that it may affect gene flow and genetic diversity. The scarcity of adult males might stem from males experiencing increased mortality while dispersing in the fragmented landscape, whereas females might be becoming more philopatric in fragments.