Stretching the Habitat Envelope: Insectivorous Bat Guilds Can Use Rubber Plantations, but Need Understorey Vegetation and Forest Buffers

Effects of land-cover change on insectivorous bat activity can be negative, neutral or positive, depending on foraging strategies of bats. In tropical agroforestry systems with high bat diversity, these effects can be complex to assess. We investigated foraging habitat use by three insectivorous bat guilds in forests and rubber plantations in the southern Western Ghats of India. Specifically, we monitored acoustic activity of bats in relation to (1) land-cover types and vegetation structure, and (2) plantation management practices. We hypothesized that activity of open-space aerial (OSA) and edge-space aerial (ESA) bat guilds would not differ; but narrow-space, flutter-detecting (NSFD) bat guild activity would be higher, in structurally heterogeneous forest habitats than monoculture rubber plantations. We found that bat activity of all guilds was highest in areas with high forest cover and lowest in rubber plantations. Higher bat activity was associated with understorey vegetation in forests and plantations, which was expected for NSFD bats, but was a surprise finding for OSA and ESA bats. Within land-cover types, open areas and edge-habitats had higher OSA and ESA activity respectively, while NSFD bats completely avoided open habitats. In terms of management practices, intensively managed rubber plantations with regular removal of understorey vegetation had the lowest bat activity for all guilds. Intensive management can undermine potential ecosystem services of insectivorous bats (e.g., insect pest-control in rubber plantations and surrounding agro-ecosystems), and magnify threats to bats from human disturbances. Low-intensity management and maintenance of forest buffers around plantations can enable persistence of insectivorous bats in tropical forest-plantation landscapes.

Variations of the Oxidative Ratio across Ecosystem Components and Seasons in a Managed Temperate Beech Forest (Leinefelde, Germany)

The oxidative ratio (OR) of organic material integrates the ratio of CO2 sequestered in biomass vs. O2 produced over longer timescales, but the temporal and spatial variability within a single ecosystem has received very limited attention. Between October 2017 and October 2019, we repeatedly sampled leaves, twigs, bark, outer stem wood, understorey vegetation and litter in a temperate beech forest close to Leinefelde (Germany) for OR measurements across a seasonal and spatial gradient. Plant component OR ranged from 1.004 ± 0.010 for fine roots to 1.089 ± 0.002 for leaves. Inter- and intra-annual differences for leaf and twig OR exist, but we found no correlation with sampling height within the canopy. Leaf OR had the highest temporal variability (minimum 1.069 ± 0.007, maximum 1.098 ± 0.002). This was expected, since leaf biomass of deciduous trees only represents the signal of the current growing season, while twig, stem and litter layer OR integrate multiple years. The sampling years 2018 and 2019 were unusually hot and dry, with low water availability in the summer, which could especially affect the August leaf OR. Total above-ground OR is dominated by the extremely stable stem OR and shows little variation (1.070 ± 0.02) throughout the two sampling years, even when facing extreme events.

Distribution and Behavioural Ecology of the Sulphur-Crested Cockatoo (Cacatua Galerita L.) in New Zealand

<p>1. Sulphur-crested cockatoos (Cacatua galerita) have colonised several sites in the North Island and on Banks Peninsula in the South Island of New Zealand. Galah (C. roseicapilla) have established in the South Auckland Region of the North Island. Original colonies are thought to have established from escaped cage birds, but the origin of populations of C. galerita that have appeared over more recent years is uncertain. 2. The distribution of C. galerita in Australia and New Zealand was modelled against environmental factors using multiple logistic regression to determine which characteristics of its environment are important in defining their distribution. 3. While C. galerita distribution in New Zealand falls within the range of ambient temperature experienced by this species in Australia, models of distribution produced from multiple logistic regression revealed temperature was not the only characteristic important in defining distribution. Instead distribution was best defined by a combination of temperature, availability of cultivated land and in New Zealand the presence of open woodland vegetation. 4. Observed daily and seasonal differences in the movement, time-activity budget, habitat use and diet of cockatoos in a population stronghold (Turakina Valley, Manawatu-Wanganui Region) were used to provide insight into the relationship between the environmental factors characteristic of C. galerita distribution and the range of this species. 5. Distribution of C. galerita was strongly influenced by the availability of crop seed mostly maize (Zea maize). In winter groups of C. galerita from large area (probably hundreds of square kilometres) congregated into a large flock, roosting in a reserve immediately adjacent to fields of maize, their main food source at this time. By congregating in this area they reduced the amount of time needed to forage for food especially time spent flying (the most energetically costly behaviour). 6. Despite greater energetic demands in winter, C. galerita in the Turakina Valley decreased the proportion of time spent feeding, instead increasing time spent resting. This was attributed to feeding on a very abundant food (maize), and lower energy demands resulting from reduced time spent flying (possible because of maize) and in feather maintenance and social behaviours. 7. Native podocarp forest remnants provided most of the non-food resource requirements of C. galerita, such as day-time refuges and nest and nocturnal roost sites. Most of their food was obtained from introduced vegetation available on the adjacent farmland, particularly cereal crops, grasses and exotic conifers. In contrast, sympatric populations of tui (Prosthemadera novaeseelandiae), bellbirds (Anthornis melanura and New Zealand pigeons (Hemiphaga novaeseelandiae) were more arboreal and preferentially foraged in native forest and exotic angiosperm tree species. 8. Freshly fallen leaves and green branches (greenfall) were collected from 100 plots in a podocarp-broadleaf forest in the Turakina Valley. Greenfall was categorised as "unexplained" or "cockatoo-caused". Leaves and branches (0-600mm) from 41 species or species groups were represented in the greenfall. Ten of these species also contributed to cockatoo-caused greenfall, including all four podocarp species and all of the epiphytic angiosperms present in the reserve. 9. Annual inputs of cockatoo-caused greenfall were compared with total foliar litter-fall measured in similar podocarp-broadleaf forests in the Orongorongo Valley, lower North Island. Although cockatoo-caused greenfall contributed only 0.08% of avenge litterfall, their impact was substantially greater for particular species, including > 5% of literfall recorded for Dacrydium cupressinum. 10. Defoliation of native tree and epiphyte species by C. galerita is considered to have potential consequences for forest dynamics, resulting in an increase in understorey vegetation, and could cause reductions in populations of some species (particularly D. cupressinum and rarer epiphytes).</p>

Distribution and Behavioural Ecology of the Sulphur-Crested Cockatoo (Cacatua Galerita L.) in New Zealand

<p>1. Sulphur-crested cockatoos (Cacatua galerita) have colonised several sites in the North Island and on Banks Peninsula in the South Island of New Zealand. Galah (C. roseicapilla) have established in the South Auckland Region of the North Island. Original colonies are thought to have established from escaped cage birds, but the origin of populations of C. galerita that have appeared over more recent years is uncertain. 2. The distribution of C. galerita in Australia and New Zealand was modelled against environmental factors using multiple logistic regression to determine which characteristics of its environment are important in defining their distribution. 3. While C. galerita distribution in New Zealand falls within the range of ambient temperature experienced by this species in Australia, models of distribution produced from multiple logistic regression revealed temperature was not the only characteristic important in defining distribution. Instead distribution was best defined by a combination of temperature, availability of cultivated land and in New Zealand the presence of open woodland vegetation. 4. Observed daily and seasonal differences in the movement, time-activity budget, habitat use and diet of cockatoos in a population stronghold (Turakina Valley, Manawatu-Wanganui Region) were used to provide insight into the relationship between the environmental factors characteristic of C. galerita distribution and the range of this species. 5. Distribution of C. galerita was strongly influenced by the availability of crop seed mostly maize (Zea maize). In winter groups of C. galerita from large area (probably hundreds of square kilometres) congregated into a large flock, roosting in a reserve immediately adjacent to fields of maize, their main food source at this time. By congregating in this area they reduced the amount of time needed to forage for food especially time spent flying (the most energetically costly behaviour). 6. Despite greater energetic demands in winter, C. galerita in the Turakina Valley decreased the proportion of time spent feeding, instead increasing time spent resting. This was attributed to feeding on a very abundant food (maize), and lower energy demands resulting from reduced time spent flying (possible because of maize) and in feather maintenance and social behaviours. 7. Native podocarp forest remnants provided most of the non-food resource requirements of C. galerita, such as day-time refuges and nest and nocturnal roost sites. Most of their food was obtained from introduced vegetation available on the adjacent farmland, particularly cereal crops, grasses and exotic conifers. In contrast, sympatric populations of tui (Prosthemadera novaeseelandiae), bellbirds (Anthornis melanura and New Zealand pigeons (Hemiphaga novaeseelandiae) were more arboreal and preferentially foraged in native forest and exotic angiosperm tree species. 8. Freshly fallen leaves and green branches (greenfall) were collected from 100 plots in a podocarp-broadleaf forest in the Turakina Valley. Greenfall was categorised as "unexplained" or "cockatoo-caused". Leaves and branches (0-600mm) from 41 species or species groups were represented in the greenfall. Ten of these species also contributed to cockatoo-caused greenfall, including all four podocarp species and all of the epiphytic angiosperms present in the reserve. 9. Annual inputs of cockatoo-caused greenfall were compared with total foliar litter-fall measured in similar podocarp-broadleaf forests in the Orongorongo Valley, lower North Island. Although cockatoo-caused greenfall contributed only 0.08% of avenge litterfall, their impact was substantially greater for particular species, including > 5% of literfall recorded for Dacrydium cupressinum. 10. Defoliation of native tree and epiphyte species by C. galerita is considered to have potential consequences for forest dynamics, resulting in an increase in understorey vegetation, and could cause reductions in populations of some species (particularly D. cupressinum and rarer epiphytes).</p>

Climate and Management Factors Underlying Changes in Beech Forest Herbaceous Layer Plant Communities in the Polish Eastern Carpathians

The herbaceous vegetation and forest stand characteristics in European beech forests growing in the Polish part of the Eastern Carpathians have changed over the last 40 years. This has been influenced by many factors, including land-use change, forest management and climate change. This study investigates changes in forest cover and structure and the associated changes in herbaceous layer plant communities and seeks to elucidate whether and how beech forest herbaceous layer communities have been affected by climate change. The study used information from archival and current land cover maps, semi-permanent sampling plots, forest management plans for the Forest Districts of Brzozów, Lesko and Ustrzyki Dolne and meteorological weather station data compiled for three study periods of herbaceous vegetation (1970s, 2000s, 2010s). In the study area, the regular shelterwood system was changed to an irregular shelterwood system that produces stands with a complex overstorey structure. The results revealed the important role of light availability in shaping the species composition of the herbaceous layer in semi-natural Carpathian beech forests, which was strongly related to the course of management activities. An overall decrease in the number of species during the 2010s is linked to the ageing of beech forests, increased intensity of management activities in ageing stands, competition from understorey vegetation and lower soil moisture that can be linked to climate change. Our study partially supports the existing findings that more manipulative forest management systems can play an important role in countering the current and expected effects of climate change on the forest ecosystem because of the low degree of spatial differentiation of the stand’s structure (developmental stages). Therefore, foresters managing the structure of stands should strive to create a forest structure with high variability of developmental stages on a regional scale.

What state of the world are we in? Targeted monitoring to detect transitions in vegetation restoration projects.

Monitoring vegetation restoration is challenging because ‘best practice’ monitoring is costly, requires long-term funding, and involves monitoring multiple vegetation variables which are often not linked back to learning about progress toward objectives. There is a clear need for the development of targeted monitoring programs that focus on a reduced set of variables that are tied to specific restoration objectives. In this paper, we present a method to progress the development of a targeted monitoring program, using a pre-existing state-and-transition model. We i) use field data to validate an expert-derived classification of woodland condition states; ii) use this data to identify which variable(s) help differentiate woodland condition states; and iii) identify the target threshold (for the variable) that signifies the desired transition has been achieved. The measured vegetation variables from each site in this study were good predictors of the different states of vegetation condition. We show that by measuring only a few of these variables, it is possible to assign the vegetation condition state for a collection of sites, and monitor if and when a transition to another state has occurred. Out of nine vegetation variables considered, the density of immature trees and percentage of exotic understorey vegetation cover were the variables most frequently specified as effective to define a threshold or transition. We synthesise findings by presenting a decision tree that provides practical guidance for the development of targeted monitoring strategies for woodland vegetation.

Mature stand developmental stage has ceased to constitute the most suitable habitat for the capercaillie in the Augustów Forest, Poland

Background Forest management affects the habitat conditions for many forest-dwelling species. Among them, the capercaillie (Tetrao urogallus) is a rare forest grouse inhabiting old, mature forests. We compared the structure of forest habitat among 9 active and 9 abandoned leks in the Augustów Forest (North-Eastern Poland), within a radius of 1 km of the leks, defined as the Key Areas for the capercaillie in lowland temperate forest. Habitat measurements were conducted on 1779 circular plots. Assessments made on all plots related to 13 habitat variables measured or noted in the field, including stand structure, canopy closure, stand developmental stage, percentage of Scots pine (Pinus sylvestris), soil fertility and soil moisture, the share of undergrowth, the cover of shrubs, the cover of bilberry (Vaccinium sp.), and the presence of certain habitat elements important to the capercaillie. Results To compare the still-occupied and the abandoned KAs for the capercaillie, a logistic regression model was developed. The variables best explaining differences between these two categories were: the occurrence of undergrowth layers, canopy closure in the second canopy layer, and stand age. According to the model, with the increase of the shrub-layer cover as well as the density of trees, the probability of the presence of the capercaillie decreased. The capercaillie in the area of the Augustów Forest occupy mainly dry and poor, middle-aged, pine-dominated forests, with a moderate extent of stand canopy closure and only weakly-developed layers of undergrowth. Conclusions The filling-in of mature stands with sub-canopy trees and shrubs (the process which is stimulated by climate change and site eutrophication) causes structural changes, which are unfavourable to the capercaillie. This might explain why in the course of the recent decades the capercaillie has abandoned the oldest stands, distinguished by the presence of bigger shares of undergrowth. The capercaillie has shifted to younger stands, which reveal a lesser extent of canopy closure and a more limited development of understorey vegetation.

Short-Term Canopy and Long-Term Effects Soil of a Native Shrub Under Arid Bioclimate: A Case Study From Tunisia

Interactions between plants (competition and facilitation) in terrestrial ecosystems include: (1) short-term effects primarily quantified with experimental removals; and (2) long-term effects primarily quantified with observational methods. This study, conducted in the National Park of Bou Hedma, examined (1) the relative contributions of short-term canopy and long-term soil effects of a shrub species in explaining differences in biomass, species diversity (richness) and species density of understory plants (i) between shrubs and open areas, (ii) between shrubs and removed shrubs; and (2) the role of grazing in driving changes in direction of short-term and long-term effects in shrub/understory species interactions.Differences in species richness, density and biomass of understorey communities between shrub removed and open areas were mostly due to long-term soil effects, whereas differences beneath shrubs and shrub removed were due to short-term canopy effects, in particular on soil water content.Our study provides the positive effect of savannas shrubs on the understorey vegetation biomass, species density and diversity in arid ecosystems. Additionally, grazing by large herbivores negatively influenced the dynamics of vegetation under an arid bioclimate.