A New Species of Gracixalus (Anura: Rhacophoridae) from Northern Vietnam

A new species of Gracixalus is described from northwestern Vietnam based on morphological differences and molecular divergence. Morphologically, the new species, Gracixalus ziegleri sp. nov., is distinguishable from its congeners on the basis of a combination of the following diagnostic characters: (1) size small (SVL 28.1 – 30.5 mm); (2) head slightly wider than long; (3) vomerine teeth absent; (4) upper eyelid and dorsum without spine; (5) supratympanic fold distinct; (6) skin of dorsal and lateral surface of head, body and limbs rough, sparsely scattered with tubercles; (7) ventral skin granular; (8) tibiotarsal projection absent; (9) toes with moderately developed webbing, formula I1 – 11/2 II1 – 2III1 – 2IV2 – 1V; (10) dorsal surface of head and body brown to beige above, with an inverse Y-shaped dark brown marking, extending from interorbital region to central region of dorsum; (11) external vocal sac absent in males; (12) males with a nuptial pad on finger I. Phylogeneticially, the new species is a sister taxon of Gracixalus sapaensis and G. tianlinensis with well-supported values. Currently, the new species is known only from the evergreen montane tropical forest of Yen Bai Province at an elevation of ca. 2200 m a.s.l.

Disentangling niche theory and beta diversity change

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favours habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e. its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

Feeding habitat of the understory arboreal snail Tikoconus costarricanus (Stylommatophora: Euconulidae) in a tropical montane wet forest, Costa Rica

Introduction: The feeding habitats of land snails are essential for their survival. Some are little known, for example the upper surface of leaves, habitat of tropical arboreal and shrub snails. Objective: To analyze the feeding behavior and preferences in the feeding habitat of the tropical snail Tikoconus costarricanus. Methods: In a humid montane tropical forest in Cartago, Costa Rica, I recorded every 3 to 4 hours the feeding activity and general behavior of individually marked snails on a 2km trail (seven 24-hour visits in May 2010-March 2011). Results: I observed a total of 167 individual specimens and made 781 observations about their behavior and the leaves on which they were found. These snails preferred monocotyledonous leaves with many epiphylls, despite the fact that those leaves were not common in this forest. They avoided ferns, and during the less rainy season, they preferred leaves with many trichomes, although there were few such leaves. On average, they spent 11 hours on each individual leaf and visited two leaves per day. The few snails seen on stems were almost always moving, as opposed to those on the leaf underside. On average they moved a net 65 cm each day. Feeding concentrated around 9:00 am and defecation around 4:20 am. Conclusions: These snails prefer leaves with many epiphylls, where they find good camouflage, moisture and food. The preference for trichomes could be due to mechanical reasons. The lack of seasonality in their behavior may reflect their stable food source in a forest that remains humid year round.

Early responses of elevated nutrient input on above-ground net primary production of a lower-montane tropical forest in Uganda

<p>Nutrient availability in tropical forest ecosystems plays a critical role in sustaining forest growth and productivity. Observational evidence for nutrient limitations on net primary productivity (NPP) in the tropics is rare yet crucial for predicting the impacts of human-induced changes on tropical forests, particularly for underrepresented tropical regions in Africa. In an ecosystem-scale nutrient manipulation experiment, we assessed the response of different components of above-ground net primary production (ANPP) to nutrient addition of nitrogen (N), phosphorus (P), potassium (K) and all possible combinations (NP, NK, PK, and NPK) at rates of 125 kg N ha<sup>-1</sup>yr<sup>-1</sup>, 50 kg P ha<sup>-1</sup> yr<sup>-1</sup> and 50 kg K ha<sup>-1</sup>yr<sup>-1</sup>.</p><p>We established 32 (8 treatments × 4 replicates) experimental plots of 40 × 40 m<sup>2</sup> each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) ≥ 1 cm as well as litter production and above-ground woody biomass production (AWBP), of a lower-montane tropical forest (1100 m a.s.l.) in northwestern Uganda.</p><p>After 18 months of nutrient addition, we found that different aspects of ANPP, including litter production and AWBP are controlled by multiple soil nutrients. Specifically, we measured higher total fine-litter production in the N (13.6 ± 1.4 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) and K (13.3 ± 1.8 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) addition plots than the control (11.1 ± 0.6 Mg ha<sup>-1 </sup>yr<sup>-1</sup>) plots. Both reproductive litter (flowers and fruits; 10% of total fine-litter fall) and leaf litter (62% of total fine-litter fall) significantly increased with K addition. In general, fine-litter production in our plots is higher than what has been reported so far for lower-montane tropical forests. Increased AWBP is associated with N addition plots. The response of trees to nutrient addition however, varied with tree sizes. Trees with dbh between 10 – 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 – 10 cm dbh) or larger trees (dbh > 30 cm). The medium-sized trees which may have experienced resource competition but have now transitioned into the canopy layer (exposed to sunlight) are able to use additional nutrient for active growth. In contrast, bigger trees may allocate extra nutrient for reproduction and leaf-vitality, while smaller trees remain shaded, co-limited by sunlight and therefore unable to utilize increased available nutrients for stem diameter growth. ANPP increased by 39% with N addition and marginally by 23% with K additions relative to the control. In conclusion, our experiment provides evidence of N and potentially K limitation of ANPP in this lower-montane tropical forest, and highlights that, in a highly diverse ecosystem different components of ANPP may be regulated by multiple nutrients. </p>

Home range and habitat use by pacas in a montane tropical forest in Bolivia

ABSTRACT We studied the home range and habitat use of paca (Cuniculus paca) in a rural agricultural community in the Alto Beni region, in La Paz department, Bolivia, where game meat is the main source of protein for a large portion of local inhabitants. We captured and radio collared five individual paca (4 females and 1 male), which were followed for six months in 2012 to estimate home range of the individuals and assess their habitat use and selection. The total mean home range (95% Minimum Convex Polygon) was 2.26 ha (SD = 0.80), and ranged from 1.5 to 2.96 ha. The mean female home range (2.04 ha) was smaller than the male´s (2.95 ha). Pacas used two (crops and fallows) of the three available habitats (secondary forest patches), and appeared to positively select crops over the other two. The importance of crops may be linked to the type of agriculture conducted in the area (i.e. mainly cacao in agroforestry systems), which may offer more food and shelter for pacas. Given that, the importance of habitats may change seasonally; this topic should be examined in future studies. Our results suggest that agroforestry systems may be important for the species since they offer a variety of food resources throughout the year.

Land-use effect on hydropedology in a mountainous region of Southeastern Brazil

ABSTRACT In Brazil, the Mantiqueira Range, southeastern region, shelters the last remnants of the ecologically important Upper Montane Tropical Forest. since extensive exploration that has been taking place in this biome for decades, the influence of land-use changes on hydropedology in these areas must be investigated once major land-use changes have been observed. This study aims to evaluate the land-use influence on soil drainable porosity (SDP) in a headwater watershed located in the Mantiqueira Range region, and to validate the proposed methods based on micromorphological and hydrological indicators. The native vegetation of the study area is Atlantic forest that occupies 62% of the area, and the remaining 38% has been used for pasture. Thirty nine combinations of environmental variables were tested, each one generating a map for predicting SDP. The performance of the spatial prediction of SDP was assessed using 20% of the data from the total number of samples collected throughout the watershed. The least values of SDP are due to the process of removal of native forest and replacement by pasture. Areas with high to moderate SDP are associated with native forest fragments demonstrating the effects of the Atlantic Forest on the water infiltration and groundwater recharge processes, given by the greater contribution of baseflow in a forested catchment located within the studied watershed. The analysis of soil micromorphological images provided useful supporting information on the soil porosity system and along with hydrological properties of the watershed helped understand the SDP behavior on subsurface and groundwater storage capacity.