Mohamed Zakaria

Ecological impacts of oil palm agriculture on forest mammals in plantation estates and smallholdings

Global oil palm expansion has caused substantial ecological damage to tropical biodiversity. We quantified wild mammal richness in large oil palm plantation estates and semi-traditional oil palm smallholdings in Peninsular Malaysia. We sampled 41 plantation estates and 14 smallholdings, and used line-transect surveys coupled with semi-structured interviews to develop a database of the native mammals found in oil palm landscapes. Semi-structured interviews revealed a total of 32 mammal species, including 13 IUCN Red Listed taxa of high conservation value. Our results showed that human activity and the size of patches of remnant rainforest were important factors influencing the richness of mammal species in oil palm landscapes. More carnivorous and herbivorous species were reported in smallholdings than plantation estates, most probably as a response to greater habitat heterogeneity in smallholdings. All species, irrespective of conservation status, were more likely to be recorded in oil palm plantation estates and smallholdings that supported large areas of native forest. Our findings suggest that biodiversity conservation in oil palm landscapes will require a variety of conservation approaches. Minimizing poaching, reducing disturbance from human activity, and protecting existing forest patches appear particularly important. Strategies to promote the persistence of both high and low conservation value species should be adopted as part of a strengthened certification scheme for oil palm production.

Contribution of illegal hunting, culling of pest species, road accidents and feral dogs to biodiversity loss in established oil-palm landscapes

Abstract Context. Understanding the ecological impacts of the palm-oil industry on native fauna requires information on anthropogenic threats that may cause species decline or local extinction. Aim. The main aim of the study was to assess wildlife deaths caused by illegal hunting, road accidents and introduced predators in established oil-palm landscapes in Peninsular Malaysia. Methods. Between April and October 2009, we interviewed 362 oil-palm workers at 36 sites, including large industrial estates and semi-traditional smallholdings. Key results. Our results showed that (1) illegal hunting by oil-palm workers in different oil-palm management systems was not statistically significant (P = 0.097), (2) native fauna were more often destroyed as pests in smallholdings than in conventional and eco-friendly plantation estates (P = 0.005), (3) non-local poachers conducted illegal activity more often in smallholdings than in conventional and eco-friendly plantation estates (P = 0.011), (4) road accidents were reported to kill more native fauna in conventional plantation estates than in smallholdings and eco-friendly plantation estates (P < 0.001) and (5) feral dogs were reported as killing more native fauna in eco-friendly plantation estates than in conventional plantation estates and smallholdings (P = 0.034). Conclusion. In addition to the conversion of native forest to oil-palm monocultures, various other anthropogenic threats can have a substantial effect on wildlife in oil-palm landscapes. Implications. To improve the conservation value of oil-palm landscapes, we recommend that palm-oil stakeholders should implement anti-poaching patrols, organise conservation programs to educate workers, reduce vehicle speeds on roads within oil-palm landscapes, and control local populations of feral dogs.

Relative abundance and diversity of waterbirds in a Persian Gulf mangrove forest, Iran

Mangrove habitats are host to many waterbirds around the globe. However, the roles of mangrove habitat structures in association with variation in individuals and their community of waterbirds have not been examined in detail. The objective of this study was to determine the abundance, diversity and evenness of waterbirds in an Avicennia mangrove habitat. The study was conducted using a point count method at Hara Protected Area (HPA) in Iran for 1 year. A total of 59,387 waterbirds observations, belonging to 56 species, were recorded and categorized based on different seasons, where 13,825 (49 spp.), 34,267 (54 spp.), 6939 (46 spp.) and 4356 (35 spp.) observations were recorded in the different seasons of fall, winter, spring and summer respectively. In total, 80.98% of individual observations had occurred during the migratory season. Dromas ardeola (11,329 observation; 19.08%) and Calidris alpina (5261 observation; 8.86%) were the most abundant, while three species including Phalacrocorax nigrogularis (4 observations), Vanellus indicus (2 observations) and Chlidonias leucopterus (2 observations) were the least abundant waders and seabird species. There were significant differences between the number of waders and seabirds observed in fall (t = 1.22, P < 0.05), winter (t = 1.27, P < 0.05), spring (t = − 0.78, P < 0.05) and summer (t = − 1.55, P < 0.05). The results also showed that there was a significant difference between the number of individuals observed in different seasons (F3,232 = 7.4, P < 0.01). The abundance of waterbirds at HPA was highest in winter while the diversity and evenness were highest in spring. The HPA is important because of the presence of exotic species such as Numenius arquata that is listed as near threatened in the red list of the International Union for Conservation of Nature. HPA mangrove forest could be one of the “megadiversity” places in the Middle East. Thus, preventing further losses of the mangrove and reducing the impacts of disturbance on birds and their habitats should be prioritized.

Bird Species Abundance and Their Correlationship with Microclimate and Habitat Variables at Natural Wetland Reserve, Peninsular Malaysia

Birds are the most conspicuous and significant component of freshwater wetland ecosystem. Presence or absence of birds may indicate the ecological conditions of the wetland area. The objectives of this study were to determine bird species abundance and their relationship with microclimate and habitat variables. Distance sampling point count method was applied for determining species abundance and multiple regressions was used for finding relationship between bird species abundance, microclimate and habitat variables. Bird species were monitored during November, 2007 to January, 2009. A total of 8728 individual birds comprising 89 species and 38 families were detected. Marsh Swamp was swarmed by 84 species (69.8%) followed open water body by 55 species (17.7%) and lotus swamp by 57 species (12.6%). Purple swamphen Porphyrio porphyrio (9.1% of all detections) was the most abundant bird species of marsh swamp, lesser whistling duck—Dendrocygna javanica (2.3%) was dominant species of open water body and pink-necked green pigeon—Treron vernans (1.7%) was most common species of lotus swamp. Results revealed that the habitat characteristics such as vegetation composition (i.e. emergent and submerged vegetations, grasses, shrubs, and trees), vegetation structures (tree diameter and height) and microclimate variables (temperature, relative humidity and light intensity) were the key factors that influenced the distribution, diversity and density of the wetland bird species. This study also revealed that the wetland bird species have adapted a fairly unique set of microhabitat and microclimate conditions.

Breeding Biology of the Crab Plover (Dromas ardeola) on the Mond Islands, Northern Persian Gulf, Iran

Abstract. The present study describes the breeding biology of Crab Plovers (Dromas ardeola), a little-known shorebird species nesting on Nakhilu and Omol-Karam Islands located in the Nakhilu Marine National Park in the northern Persian Gulf, Iran. This study occurred during the breeding seasons of 2009–2011. Colonies had between 500–1,500 nests and were located on sand banks 1–3 m higher than the surrounding ground in non-overlapping areas. Burrow digging began in mid-April, and single nests were built in 2.82 ± 0.1 days (Range = 2–4 days, n = 45) in a period of 10.5 ± 0.76 days (Range = 8–13 days, n = 6), although a spread of digging and laying of 87.50 ± 2.96 days (Range = 82–94 days, n = 4) was recorded primarily due to renesting after human damage to the burrows. Range in nest densities was 0.14–0.26 nest per m2. The clutch size was 1.01 ± 0.005 (Range = 1-2, n = 421). Egg size (n = 47) was 64.05 × 44.04 mm with an average incubation period of 33 days (Range = 31–35, n = 21). Hatching success was 63–81%, with failures primarily due to egg collecting by local fishermen and tourists. An estimated of 7 weeks passed between hatching and fledging. Fledglings had almost fully developed wings (83% of adult wing length) and feathers, but very low weight (about 55% of adult weight) and smaller bill length (only 60% of adult bill length). A stronger control of visitors and local fishermen would benefit the breeding population of Crab Plovers on the islands.

Effects of water level fluctuation on waterbirds distribution and aquatic vegetation composition at Natural Wetland Reserve, Peninsular Malaysia.

The effects of water level fluctuations on waterbirds distribution and aquatic vegetation composition was determined using distance sampling point count method and direct visual observation at Paya Indah Natural Wetland Reserve, Peninsular Malaysia. A total of 2563 waterbird individual of 28 species and 8 families were detected in three habitats, that is, marsh swamp (68.59%), open water body (18.42%), and lotus swamp (12.99%). Porphyrio porphyrio was the most dominant species in marsh swamp (45.39%), and lotus swamp (23.42%), whereas Dendrocygna javanica (42.16%) was the most abundant in open water body. The highest water level for marsh swamp (2.313 m) and lotus swamp (2.249 m) was recorded in January, 2008 and for open water body (2.572 m) in January and April, 2008. In contrast, the lowest water level for marsh swamp (2.048 m) and lotus swamp (1.834 m) was determined in October, 2008 and for open water body (2.398 m) in January, 2009. Pearson test indicates weak linear correlationship between water level and waterbird abundance in lotus swamp habitat ( 𝑟 2 = 0 . 1 2 0 , 𝑃 > 0 . 0 5 ) and in marsh swamp ( 𝑟 2 = 0 . 1 0 0 , 𝑃 > 0 . 0 5 ) and negative linear correlationship ( 𝑟 2 = − 0 . 7 1 0 , 𝑃 > 0 . 0 5 ) in open water body habitat. Canonical correspondence analysis indicated strong correlationship between waterbird abundance and vegetation (73.0%) in open water body, and weaker association (29.8%) in lotus swamp. The results of this study indicate that water level is a major factor that influences the relative abundance and distribution of ducks, swamphen, crakes, herons, jacanas, and moorhens directly and indirectly. In addition, it also effects on the dynamics of aquatic vegetation composition such as, emergent, submerged, and grasses in this wetland reserve.

Assessing an Artificial Wetland in Putrajaya, Malaysia, as an Alternate Habitat for Waterbirds

Abstract. Detailed information on bird populations and wetland habitats is highly important for future conservation and management activities. More than 50% of natural wetland habitats have been lost or degraded due to human intervention, which has negatively affected wetland-dependent bird populations. In this study, the density, diversity and feeding guilds of various bird species in an artificial wetland habitat were examined using a distance sampling point count technique. A total of 20,010 individuals of 102 species representing 40 families were detected from March 2009 to June 2010. In all, 64 species were counted with 72.5% of 14,520 individuals residents, 22 species were counted with 26.4% of 5,290 individuals resident-migrants, 13 species were counted with 1.0% of 196 individuals migrants and three species were counted with 0.1% of four individuals counted vagrants. Resident birds were present at the highest density and vagrants at the lowest. The most dominant migrant, resident and resident-migrant species were the Oriental Reed Warbler (Acrocephalus orientalis) (0.37 ±0.10 birds ha-1), Rock Pigeon ( Columba livia) (3.91 + 0.97 birds ha-1) and Purple Heron (Ardea purpurea) (1.55 ± 0.93 birds ha-1), respectively. The community structure of resident birds was the most diverse and rich compared to migrants, resident-migrants and vagrants. Frugivore/insectivore (1.04 ± 0.20 birds ha-1) was the most dominant feeding guild for migrants, nectarivore/insectivore (0.64 ± 0.04 birds ha-1) for residents and omnivore (0.28 ± 0.03 birds ha-1) for resident-migrants. The findings of this research indicate that artificial wetlands can provide an alternative habitat for the foraging and breeding activities of different bird assemblages.

Relationships among rat numbers, abundance of oil palm fruit and damage levels to fruit in an oil palm plantation.

The relationships between vertebrate pests and crop damage are often complex and difficult to study. In palm oil plantations rodents remain the major pests, causing substantial monetary losses. The present study examined the numerical and functional responses of rodents to changes in the availability of oil palm fruit and the damage associated with that response. For the study, 200 traps were set in pairs on a 10 × 10 trapping grid for 3 consecutive nights in each of 6 study plots at 8-week intervals in a 2569 ha oil palm plantation at Labu, Negeri Sembilan state in Peninsular Malaysia over 14 months. A total of 1292 individual rats were captured over 25 200 trap-nights. Animals were identified, aged, sexed, weighed and measured. An index of the relative abundance of rats was calculated based on trapping success. Damage to infructescences was assessed at each trap point. Regardless of the age of palms, there were positive and significant relationships between the relative abundance of rats and numbers of infructescences. The levels of damage to infructescences were significantly correlated with the relative abundance of rats. A steep increase in damage was observed with an increase in mature infructescences, indicating a feeding preference of rats for mature infructescences. For both males and females of all rat species, there were weak and non-significant correlations between body condition and infructescence numbers. These results indicated that there was a numerical and a functional response by rats to the availability of palm fruit and a resulting increase in depredation of oil palm fruits. The ways in which this information might aid in future pest control are discussed.

Foraging ecology and occurrence of 7 sympatric babbler species (Timaliidae) in the lowland rainforest of Borneo and peninsular Malaysia

Abstract Understanding foraging strategies of birds is essential to understanding mechanisms of their community assembly. To provide such information on a key Southeast Asian rainforest family, the babblers (Timaliidae), we evaluated foraging behavior and abundance in 7 morphologically and behaviorally similar sympatric species (Cyanoderma erythropterum, C. rufifrons, Stachyris maculata, S. nigricollis, S. poliocephala, Macronus ptilosus, and Mixornis gularis) in 5 habitats defined by structural complexity: (1) continuous native rainforest, (2) logged native rainforest fragments, (3) mature industrial tree plantation, (4) young industrial plantation, and (5) oil palm plantation. Enough data were obtained to compare abundance in all 7 species and foraging behavior in 5. All species were common in forest fragments and mature industrial tree plantations and less so in continuous rainforest and young industrial plantations; only M. gularis occurred in oil palm. In terms of foraging, M. gularis was the greatest generalist; C. rufifrons foraged mainly on live leaves in the forest midstory; and S. maculata, C. erythropterum, and M. ptilosus foraged mainly on dead leaves suspended in understory vegetation at significantly different heights. The dead-leaf substrate depends on a rich supply of falling leaves and extensive understory structure, conditions most common in native forest and old industrial plantations, and less so in mature forest, young plantations, and oil palm. Because of the importance of foraging data to understanding and managing biodiversity, we encourage the development of foraging fields in eBird (ebird.org), so that birdwatchers may help collect these relatively rare data.

Comparison of understorey bird species in relation to edge–interior gradient in an isolated tropical rainforest of Malaysia

Forest fragmentation results in a loss of forest interior and an increase in edge habitat. As a result, these changes may affect the bird species distribution and composition. We studied how understorey bird community composition and habitat variables changed along an edge-to-interior gradient in a fragmented lowland rainforest in Peninsular Malaysia. Birds and environmental variables were recorded at each of the 93 sampling points distributed along the 14 parallel transects that were systematically placed across the gradient of distance from the forest edge to the forest interior. Species composition was different along the edge–interior gradient, although only a few species were strictly confined to either edge or interior habitat. Based on bird–habitat associations along the edge–interior gradient, some of these edge-preferred species occurred in high numbers at the matrix surrounding the patch. In contrast, the interior-specialist group, mainly terrestrial insectivores, avoided the forest edge and was positively associated with humidity, canopy cover, the number of dead trees, percentage of litter cover, and depth of the litter layer. Species endemic to the Sunda subregion were more abundant in the interior of the forest. From a conservation perspective, forest remnants in the lowlands of Peninsular Malaysia that have a deep leaf litter layer, dense canopy cover, high number of dead trees, and high relative humidity are able to support understorey bird species that are sensitive to edge effects. The forest has important conservation value even though it is fragmented and isolated.