scholarly journals Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

2016 ◽  
Vol 06 (02) ◽  
pp. 142-161 ◽  
Author(s):  
Chemuku Wekesa ◽  
Nereoh Leley ◽  
Elias Maranga ◽  
Bernard Kirui ◽  
Gabriel Muturi ◽  
...  
Keyword(s):  
Vegetation Structure ◽  
Forest Disturbance ◽  
Forest Patches ◽  
Taita Hills

scholarly journals Gamebird responses to anthropogenic forest fragmentation and degradation in a southern Amazonian landscape

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3442 ◽  
Author(s):  
Fernanda Michalski ◽  
Carlos A. Peres
Keyword(s):  
Forest Fragmentation ◽  
Census Data ◽  
Forest Disturbance ◽  
Selective Logging ◽  
Forest Birds ◽  
Line Transect ◽  
Forest Patches ◽  
Forest Patch ◽  
Species Persistence ◽  
Gamebird Species

Although large-bodied tropical forest birds are impacted by both habitat loss and fragmentation, their patterns of habitat occupancy will also depend on the degree of forest habitat disturbance, which may interact synergistically or additively with fragmentation effects. Here, we examine the effects of forest patch and landscape metrics, and levels of forest disturbance on the patterns of persistence of six gamebird taxa in the southern Brazilian Amazon. We use both interview data conducted with long-term residents and/or landowners from 129 remnant forest patches and 15 continuous forest sites and line-transect census data from a subset of 21 forest patches and two continuous forests. Forest patch area was the strongest predictor of species persistence, explaining as much as 46% of the overall variation in gamebird species richness. Logistic regression models showed that anthropogenic disturbance—including surface wildfires, selective logging and hunting pressure—had a variety of effects on species persistence. Most large-bodied gamebird species were sensitive to forest fragmentation, occupying primarily large, high-quality forest patches in higher abundances, and were typically absent from patches <100 ha. Our findings highlight the importance of large (>10,000 ha), relatively undisturbed forest patches to both maximize persistence and maintain baseline abundances of large neotropical forest birds.

scholarly journals Vocalization Analyses of Nocturnal Arboreal Mammals of the Taita Hills, Kenya

Diversity ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 473
Author(s):  
Hanna Rosti ◽  
Henry Pihlström ◽  
Simon Bearder ◽  
Petri Pellikka ◽  
Jouko Rikkinen
Keyword(s):  
Cloud Forest ◽  
Contact Call ◽  
Mammal Species ◽  
Montane Forests ◽  
Forest Patches ◽  
Otolemur Garnettii ◽  
Loud Calls ◽  
Call Structure ◽  
Taita Hills ◽  
Contact Calls

Three poorly known nocturnal mammal species from the montane forests of the Taita Hills in Kenya, were studied via vocalization analysis. Here, their acoustic behaviour is described. The studied animals were the tree hyrax (Dendrohyrax sp.), the small-eared greater galago (Otolemur garnettii), and the dwarf galago (Paragalago sp.). High-quality loud calls were analysed using RAVEN PRO, and compared to calls of presumed closest relatives. Our findings include the first detailed descriptions of tree hyrax songs. Moreover, our results suggest that the tree hyrax of Taita Hills may be a taxon new to science, as it produces a characteristic call, the ‘strangled thwack’, not previously known from other Dendrohyrax populations. Our data confirms that the small-eared greater galago subspecies living in the Taita Hills is Otolemur garnettii lasiotis. The loud calls of the elusive Taita Hills dwarf galago closely resemble those of the Kenya coast dwarf galago (Paragalago cocos). Thus, the population in the Taita Hills probably belongs to this species. The Taita Hills dwarf galagos are geographically isolated from other dwarf galago populations, and live in montane cloud forest, which is an unusual habitat for P. cocos. Intriguingly, two dwarf galago subpopulations living in separate forest patches in the Taita Hills, Ngangao and Mbololo, have clearly different contact calls. The Paragalagos in Mbololo Forest may represent a population of P. cocos with a derived call repertoire, or, alternatively, they may actually be mountain dwarf galagos (P. orinus). Hence, differences in habitat, behaviour, and contact call structure suggest that there may be two different Paragalago species in the montane forests of the Taita Hills.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Closed Canopy ◽  
Availability Index ◽  
Web Building

Indirect effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in Pennsylvania and Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Wisconsin sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was also higher in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread throughout the region.

Effects of vegetation structure and edge habitat on the density and distribution of white-footed mice (Peromyscus leucopus) in small and large forest patches

2003 ◽  
Vol 81 (5) ◽  
pp. 897-904 ◽  
Author(s):  
Christine S Anderson ◽  
Alan B Cady ◽  
Douglas B Meikle
Keyword(s):  
Vegetation Structure ◽  
Large Range ◽  
Peromyscus Leucopus ◽  
Structural Complexity ◽  
Understory Vegetation ◽  
Small Range ◽  
Forest Patches ◽  
Edge Habitat ◽  
The Difference ◽  
Small Forest

We tested the hypothesis that if the quality or quantity of vegetation in small forest patches is greater than in large patches, then vegetation attributes may contribute to greater densities of white-footed mice (Peromyscus leucopus) in smaller patches. We trapped more mice per hectare in small (range 5–9 ha) than in large (range 110–150 ha) patches, as has been reported by other investigators. The difference appeared to be due primarily to the disproportionately high densities of P. leucopus in the edge habitat of small patches. While the greater edge-to-interior ratio in small patches could contribute to greater overall densities of mice in small patches, we trapped the same relative amount of edge and interior habitats in each of the six study patches. The structural complexity of understory vegetation was much greater in small than in large patches and also in edge than in interior habitats across the six patches. Thus, we trapped the most mice in the most structurally complex vegetation (i.e., edges of small patches). However, while vegetation at the edge of large patches was more complex than in the interior, we did not capture relatively high densities of P. leucopus in edge habitat of large patches. Hence, understory vegetation may differentially influence the distribution of P. leucopus between edge and interior habitats in forest patches of different sizes.

scholarly journals Using scientific evidence to guide the conservation of a highly fragmented and threatened Afrotropical forest

Oryx ◽  
2004 ◽  
Vol 38 (4) ◽  
pp. 404-409 ◽  
Author(s):  
Mwangi Githiru ◽  
Luc Lens
Keyword(s):  
Spatial Structure ◽  
Forest Disturbance ◽  
Scientific Evidence ◽  
Conservation Strategies ◽  
Widespread Occurrence ◽  
Forest Dependence ◽  
Conservation Implications ◽  
Taita Hills ◽  
Remedial Actions ◽  
Patchy Population

Fragmentation of forests adversely affects forest-dependent biota, and conservation biologists strive to develop a good understanding of how species respond to changes associated with habitat attrition in order to establish the best conservation strategies. The spatial structure of populations persisting in fragmented landscapes governs their response to habitat fragmentation, and hence dictates the remedial actions that will be most effective for species and habitat conservation. The Taita Hills forests of Kenya are an example of a highly fragmented Afrotropical forest ecosystem embedded in a human-dominated landscape. The spatial structure of the white-starred robin Pogonocichla stellata populations living in indigenous forests across this landscape was examined. Due to its forest dependence and widespread occurrence, the robin was used as a model species to help formulate general conservation guidelines for forest-dependent species and their habitats within this landscape. Results from demographic, genetic and behavioural work point to a mixed spatial structure with elements of patchy population dynamics on a fine scale, and a core-satellite or source-pseudo-sink system on a broader scale. In particular, the findings underscore (1) the importance of dispersal, (2) the importance of small patches, (3) the importance of the largest patch, and (4) the processes underlying problems associated with forest disturbance. We examine the conservation implications of this information, and report on activities already initiated or planned, in line with these findings, for the Taita Hills.

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