Showing papers in "The Open Ecology Journal in 2014"

Herbivore Dynamics and Range Contraction in Kajiado County Kenya: Climate and Land Use Changes, Population Pressures, Governance, Policy and Human-wildlife Conflicts

Abstract: Wildlife populations are declining severely in many protected areas and unprotected pastoral areas of Africa. Rapid large-scale land use changes, poaching, climate change, rising population pressures, governance, policy, economic and socio-cultural transformations and competition with livestock all contribute to the declines in abundance. Here we analyze the population dynamics of 15 wildlife and four livestock species monitored using aerial surveys from 1977 to 2011 within Kajiado County of Kenya, with a rapidly expanding human population, settlements, cultivation and other developments. The abundance of the 14 most common wildlife species declined by 67% on average (2% / yr) between 1977 and 2011 in both Eastern (Amboseli Ecosystem) and Western Kajiado. The species that declined the most were buffalo, impala, wildebeest, waterbuck, oryx, hartebeest, Thomson's gazelle and gerenuk in Eastern Kajiado (70% to 88%) and oryx, hartebeest, impala, buffalo, waterbuck, giraffe, eland and gerenuk in Western Kajiado (77% to 99%). Only elephant (115%) and ostrich (216%) numbers increased contemporaneously in Eastern and Western Kajiado, respectively. Cattle and donkey numbers also decreased on average by 78% in Eastern Kajiado and by 37% in Western Kajiado. Sheep and goats decreased the least in Eastern (28%) but increased in Western (96%) Kajiadio. Livestock dominated (70-80%) the total large herbivore biomass throughout the 1977-2011 monitoring period. The distribution of wildlife contracted dramatically during 1977-2011, most especially for wildebeest, giraffe and impala. Only zebra and ostrich distributions expanded in the county. However, livestock distribution expanded to densely cover most of the county. Our findings point to recurrent droughts, intensifying human population pressures, land use changes and other anthropogenic impacts, decades of ineffective or failed government policies, legislations, law enforcement, management institutions and strategies as the salient causes of the declines and range compressions. We recommend several urgent measures to rehabilitate the depleted wildlife populations and habitat richness, restore their ecological resilience to droughts and secure pastoral livelihoods.

Effects of Fire and Commercial Thinning on Future Habitat of theNorthern Spotted Owl

Abstract: The Northern Spotted Owl (Strix occidentalis caurina) is an emblematic, threatened raptor associated with dense, late-successional forests in the Pacific Northwest, USA. Concerns over high-severity fire and reduced timber harvesting have led to programs to commercially thin forests, and this may occur within habitat designated as "critical" for spotted owls. However, thinning is only allowed under the U.S. Government spotted owl guidelines if the long-term benefits clearly outweigh adverse impacts. This possibility remains uncertain. Adverse impacts from commercial thinning may be caused by removal of key habitat elements and creation of forests that are more open than those likely to be occupied by spotted owls. Benefits of thinning may accrue through reduction in high-severity fire, yet whether the fire- reduction benefits accrue faster than the adverse impacts of reduced late-successional habitat from thinning remains an untested hypothesis. We found that rotations of severe fire (the time required for high-severity fire to burn an area equal to the area of interest once) in spotted owl habitat since 1996, the earliest date we could use, were 362 and 913 years for the two regions of interest: the Klamath and dry Cascades. Using empirical data, we calculated the future amount of spotted owl habitat that may be maintained with these rates of high-severity fire and ongoing forest regrowth rates with and without commercial thinning. Over 40 years, habitat loss would be far greater than with no thinning because, under a "best case" scenario, thinning reduced 3.4 and 6.0 times more dense, late-successional forest than it prevented from burning in high-severity fire in the Klamath and dry Cascades, respectively. Even if rates of fire increase substantially, the requirement that the long-term benefits of commercial thinning clearly outweigh adverse impacts is not attainable with commercial thinning in spotted owl habitat. It is also becoming increasingly recognized that exclusion of high-severity fire may not benefit spotted owls in areas where owls evolved with reoccurring fires in the landscape.

"Green" Composites for North-Arctic Region Development

Abstract: This paper discusses some of the major environmental problems of North-Arctic region. It has been proposed to use provisions of Architectural geonics and "green" composite compounds with nanodisperse organic mineral additive to improve the ecological situation in the region and enhance the effectiveness of the "Man-Material-Habitat" system.

Impact of Hydroelectric Projects on Bivalve Clams in the SharavathiEstuary of Indian West Coast

Abstract: The impact of freshwater discharges from upstream hydroelectric projects on estuarine ecology, particularly on commercial bivalves was seldom ever studied, despite the fact that they contribute substantially to local livelihoods. Such projects have been executed in many rivers of Indian Western Ghats unmindful of their ecological consequences. Through a period of the past five decades, two hydroelectric projects were commissioned in the river Sharavathi of central west coast, in the district of Uttara Kannada, Karnataka. Obvious consequences were on mangrove vegetation and fishery, and the livelihoods of fisher-folks were also badly affected. This study in the Sharavathi estuary is with the special objective of assessing the impact on commercial clams of incessant releases of freshwater after power production. For comparison, the study was also carried out in the undammed Gangavali River estuary in the same district. The study covers the diversity and distribution of commercial bivalves in relation to salinity, the key factor that expectedly gets altered due to freshwater releases from dams. The status of bivalves was collected through primary observations, interviews with local fisher-folks, and based on earlier studies. Whereas clam fishery involving Paphia malabarica, Meretrix meretrix, M. casta, Tegillarca granosa, Polymesoda erosa and Villorita cyprinoides goes on rather unchanged in Gangavali estuary, Sharavathi witnessed collapse of clam fishery, following salinity decline, indicative collapse of estuarine ecosystems itself. All clams gathered earlier, barring a lone species Polymesoda erosa, tolerant of low salinity remained here.

Survey of the Patterns of Nest Box Use Among Squirrels (Sciuridae) in Managed Forest Stands in Clinton County, New York

Abstract: Artificial habitat enhancements are important forest structural components that can increase the survival of squirrels (Sciuridae) and thus warrant study. Investigations of squirrel nest box usage can provide useful demographic and community information such as occupancy rates, litter size, habitat preference, species richness and abundance estimates. This artificial nest box study investigated the nesting patterns of squirrels from late winter through early fall 2011 in managed forest stands in Clinton County, New York. Squirrels are sensitive to forest disturbance, hence we compared sites of varying silvicultural activity (e.g., managed for production of timber or maple syrup versus an undisturbed reference stand). A total of 48 nest boxes were constructed and monitored across three separate sites (e.g., reference, logged, and sugaring). Prior research suggested that occupancy may be a function of nest box height (~3.5m and ~5m) and site-specific tree cavity/snags/drey abundance, thus height preference and alternative nesting options were monitored in the survey and analyzed to report detection probability and occupancy estimates in Program Presence. Visual confirmation of northern flying squirrels (Glaucomys sabrinus Shaw) was made in 81%, 44%, and 13% of the nest boxes in the reference, logged, and sugar site, respectively. Approximately 79% of the nest boxes showed evidence of wildlife visitation (e.g., scat, crushed seeds, or nesting material). Additionally, 87% of the high boxes (5m) versus 71% of the low boxes (3.5m) were utilized, and 17% of all occupancies contained multiple individuals. This survey provides additional multi-season occupancy data for an elusive mammal species under managed habitat regimes. We recommend that management plans include a wildlife habitat component that maintains snag trees and live cavity-trees in forest stands. When appropriate, stand management plans could also include installing habitat enhancement structures such as artificial nest boxes for squirrels.