Open Understory Research Articles

Home ranges, habitat selection, and energy expenditure of Strix varia (Barred Owls): Understanding the full diel cycle matters for enhancing urban landscapes

Abstract We integrated GPS and accelerometer data to examine habitat selection and energy expenditure patterns across the diel cycle in Strix varia (Barred Owls), addressing a critical gap in wildlife research that often overlooks activity during the “inactive” phase. Owls in Baton Rouge, Louisiana, selected forests with tall canopies and open understories, particularly in affluent neighborhoods, supporting the “luxury effect” in urban biodiversity. Nocturnal home ranges were larger (31.8 ha) compared to diurnal home ranges (8.9 ha), indicating broader habitat use at night. The total area of preferred nocturnal habitat was 33% of the Baton Rouge study area, whereas preferred diurnal habitat comprised only 5%. Energy expenditure was inversely related to preference in nocturnal home ranges but increased with preference in diurnal home ranges. Our models were validated using independent data from Clemson, South Carolina, supporting the robustness of our analysis and revealing generalities in owl habitat selection across these regions. This research contributes to a deeper understanding of urban ecology, highlighting habitat components preferred by owls and possibly other forest-dwelling species. It emphasizes the difference in nocturnal and diurnal home range sizes, the scarcity of daytime refuges for S. varia in urban landscapes, and the variation in energy expenditure in preferred habitats. Our findings advocate for urban designs that accommodate wildlife activity throughout the day and night, and highlight the positive correlation between preferred owl habitat and affluent neighborhoods, underscoring the need for equitable distribution of green spaces to foster biodiversity across socioeconomic gradients. These insights will help develop strategies to enhance the ecological value of urban environments and the conservation of S. varia and associated forest-dwelling species in rapidly urbanizing areas.

Dynamic, multi-scale analyses indicate site- and landscape-level forest cover drive Yellow-billed and Black-billed Cuckoo interannual turnover.

Studies of habitat use in breeding birds often assume species have relatively stable breeding distributions. Some species, however, display considerable year-to-year variability, complicating efforts to determine suitable or preferred habitats. After returning to their breeding range, Black-billed Cuckoos (Coccyzus erythropthalmus) and Yellow-billed Cuckoos (C. americanus) are thought to range widely before nesting, resulting in high rates of interannual breeding-site turnover, potentially contributing to conflicting habitat associations found in past studies. However, difficulty detecting these rare and declining species could lead to overinflated estimates of interannual turnover. Using broadcast surveys to increase detection probability, we collected detection/non-detection data in 2019 and 2020 at 41 publicly owned sites in Illinois and performed a dynamic, multi-scale occupancy analysis for each species to separate detection probability from potential interannual turnover and determine landscape and small-scale variables driving habitat use and occupancy dynamics. We found strong support for interannual turnover for both species based on poor performance of non-dynamic models and variation in estimated annual occupancy (20% and 21% increase between years for Black-billed and Yellow-billed Cuckoos, respectively). Black-billed Cuckoos persisted at sites with less forest in the surrounding landscape and used areas with denser understory vegetation. Yellow-billed Cuckoos colonized sites with greater canopy cover, avoided developed landscapes, and used areas with a shorter subcanopy layer. The dynamic nature of habitat use in these two cuckoo species suggests the importance of coordinating management and conservation across a broader spatial scale. Managing for larger patches of dense shrubs in less forested landscapes would benefit Black-billed Cuckoos while Yellow-billed cuckoos would benefit from management creating forested areas with open understories in less-developed landscapes.

Reproduction drives changes in space use and habitat selection in a highly adaptable invasive mammal

Abstract For ungulates, it is not well understood how the interaction between habitat and reproduction affects movement behavior, space use, and habitat selection. We used known parturition (farrowing) data to validate First Passage Time (FPT) movement analysis to identify wild pig (Sus scrofa) parturition events from data collected with GPS collars. We examined home range and habitat selection during three physiologically distinct time periods in the reproductive cycle: late-gestation; farrowing; and neonate-care period. Sows exhibited a behavioral change 1-2 days prior to farrowing, suggesting FPT analysis can reliably identify parturition events for wide-ranging species that have a focused birthing area. Home range was smallest during the farrowing period, likely reflective of nest building, parturition, and protection of neonates. Home range size during the neonate-care period was intermediate between the late-gestation and farrowing periods, indicative of offspring care that may restrict maternal movement. Across all periods, sows avoided developed areas that have sparse canopy and ground cover and are associated with human activities. During late-gestation, sows avoided pine forests that have an open understory and less vegetative cover. During late-gestation and neonate-care, sows selected bottomland hardwood forests, habitat associated with ample food, cover, and water. During farrowing and neonate-care periods, sows selected upland hardwood forests, habitat with high quality food and cover for neonates. The physiological requirements of reproduction drive female habitat selection and spatial scale of movement patterns associated with parturition. Our study contributes to delineation of the appropriate scale at which to analyze movement data to provide insight about where individuals chose to place their home range, how much space to use, and how they use resources on the landscape to maximize reproductive success and fitness.

The influence of forest management practices on seasonal bat species occurrence and activity at the Kisatchie National Forest in Louisiana, USA

In the southeastern United States, where forests are the primary land cover type, understanding how forest stand characteristics and forest management practices influence bat distributions is critical for bat conservation and management. We deployed passive acoustic monitors to record bat calls at sites representing six forest types at the Kisatchie National Forest in central Louisiana during two winter (January–February 2020 and December 2020–February 2021) and two summer (June–August 2020 and 2021) periods. We also collected environmental data at the landscape and local scales to help explain patterns in bat species occurrence. We detected big brown bats (Eptesicus fuscus), eastern red/Seminole bats (Lasiurus borealis/L. seminolus), Myotis species, tricolored bats (Perimyotis subflavus), Mexican free-tailed bats (Tadarida brasiliensis), and hoary bats (Aeorestes cinereus) during both periods, and additionally detected evening bats (Nycticeius humeralis) during the summer. We observed seasonal differences in habitat use, and found that three bat species were more active during the summer in pine forests with group selection harvest, pine forests managed for red-cockaded woodpeckers (Leuconotopicus borealis), and pine forests that were clearcut within five years of our study when compared to unmanaged pine forests, thinned pine forests, and bottomland hardwood forests. Contrary to other studies, we found that the predicted probability of occupancy decreased with increasing proximity to riparian areas for four bat species, which could reflect the complex understory vegetation conditions that we observed along the riparian corridors in our study area. Our research identified forest characteristics and management practices that promote bat species diversity and activity in central Louisiana and demonstrated that pine forests with open understories and small openings in the canopy provide important foraging habitat for bats that occur in our study area and possibly other regions in the southeast.

Detecting nighttime inversions in the interior of a Douglas fir canopy

Despite the importance of forests in the water and carbon cycles, accurately measuring their contribution remains challenging, especially at night. During clear-sky nights current models and theories fail, as non-turbulent flows and spatial heterogeneity become more important. One of the standing issues is the ‘decoupling’ of the air masses in and above the canopy, where little turbulent exchange takes place, thus preventing proper measurement of atmospheric fluxes. Temperature inversions, where lower air is colder and thus more dense, can be both the cause and result of this decoupling.With Distributed Temperature Sensing (DTS) it is now possible to detect these temperature inversions, and increase our understanding of the decoupling mechanism. With DTS we detected strong inversions within the canopy of a tall Douglas Fir stand. The inversions formed in on clear-sky nights with low turbulence, and preferentially formed in the open understory. A second inversion regularly occurred above the canopy. Oscillations in this upper inversion transferred vertically through the canopy and induced oscillations in the lower inversion.We hypothesize that the inversions could form due to a local suppression of turbulent motions along the height of the canopy. This was supported by a 1-D conceptual model, which showed that a local inversion layer would always form within the canopy if the bulk inversion (over the full canopy) was strong enough.Due to the near-continuous vertical motion and specific height the inversions occur at, a very high measurement density (better than ∼2 m) and measurement frequency (>0.1 Hz) are required to detect them. Consequently, it could be possible that the observed inversions are a regular feature in similarly structured forests, but are generally not directly observed. With DTS it is possible to detect and describe these types of features, which will aid in improving our understanding of atmospheric flows over complex terrain such as forests.

Exploring golden eagle habitat preference using lidar-based canopy bulk density

ABSTRACT A lidar-derived canopy height profile (CHP), generated from canopy bulk density (CBD) estimates for a sequence of 1-m increments through the canopy, provides a physical measure of forest structure. Measurement of physical properties are intuitively understandable and thus facilitate the use of lidar for investigating hypotheses regarding avian resource use. We illustrate the use of lidar-derived physical measures to explore the hypothesis that golden eagles (Aquila chrysaetos) prefer an open understory, which potentially aids visual identification of prey. Two golden eagles fitted with GPS tracking devices overwintered in the New Jersey Pinelands National Preserve. We generated CHPs from discrete-return lidar data for an area occupied by the birds. We compared the CHPs of sites the birds occupied to the surrounding available habitat and found that the occupied sites were significantly lower in CBD from the ground up to 5 m for perched/stationary birds, and from the ground up to 8 m for birds in flight. These results could be used by forest resource managers for promoting golden eagle habitat through prescribed fire. In addition, these results demonstrate the power of lidar to generate physically and intuitively meaningful measures of forest structure.

Nest Site Characteristics of Two Endangered Seabirds in Montane Wet Forests on the Island of Kaua‘i, Hawai‘i, USA

The nest site characteristics of two endangered seabird species–the Hawaiian Petrel Pterodroma sandwichensis and Newell's Shearwater Puffinus newelli–on Kaua‘i were considered. Burrows of both species were predominantly found under tree roots or small caves on steep slopes and were associated with native plants, both in the canopy (particularly Metrosideros polymorpha) and the understory (particularly Dicranopteris linearis). There were, however, marked differences between the two species. Hawaiian Petrels were found at higher elevations with a shorter, patchy canopy and more open understory. Models using microhabitat variables were better able to classify burrows than those using landscape topographic metrics, suggesting that metrics describing the immediate area around the burrow are more important to burrow selection. A comparative model indicated that elevation and maximum vegetation height were the strongest variables in classifying between the two species. Understanding microhabitat needs for these species is important for locating new colonies and for the successful implementation of management actions such as colony creation through social attraction. Furthermore, with the spread of Rapid’Ōhi’a Death canker disease Ceratocystis huliohia on Kaua‘i, the heavy reliance by both species on forest dominated by M. polymorpha (the tree killed by this disease) should be of increasing consideration for conservation efforts targeting these species.

Taxonomic revision of south-eastern Australian giant burrowing frogs (Anura: Limnodynastidae: Heleioporus Gray).

The rarely encountered giant burrowing frog, Heleioporus australiacus, is distributed widely in a variety of sclerophyll forest habitats east of the Great Dividing Range in south-eastern Australia. Analyses of variation in nucleotide sequences of the mitochondrial ND4 gene and thousands of nuclear gene SNPs revealed the presence of two deeply divergent lineages. Multivariate morphological comparisons show the two lineages differ in body proportions with > 91% of individuals being correctly classified in DFA. The two lineages differ in the number and size of spots on the lateral surfaces and the degree by which the cloaca is surrounded by colour patches. The mating calls are significantly different in number of pulses in the note. The presence of a F2 hybrid in the area where the distribution of the two taxa come into closest proximity leads us to assign subspecies status to the lineages, as we have not been able to assess the extent of potential genetic introgression. In our sampling, the F2 hybrid sample sits within an otherwise unsampled gap of ~90km between the distributions of the two lineages. The nominate northern sub-species is restricted to the Sydney Basin bioregion, while the newly recognised southern subspecies occurs from south of the Kangaroo Valley in the mid-southern coast of New South Wales to near Walhalla in central Gippsland in Victoria. The habitat of the two subspecies is remarkably similar. Adults spend large portions of their lives on the forest floor where they forage and burrow in a variety of vegetation communities. The southern subspecies occurs most commonly in dry sclerophyll forests with an open understory in the south and in open forest and heath communities with a dense understory in the north of its distribution. The northern subspecies is also found in dry open forests and heaths in association with eroded sandstone landscapes in the Sydney Basin bioregion. Males of both taxa call from both constructed burrows and open positions on small streams, differing from the five Western Australian species of Heleioporus where males call only from constructed burrows. Using the IUCN Red List process, we found that the extent of occupancy and area of occupancy along with evidence of decline for both subspecies are consistent with the criteria for Endangered (A2(c)B2(a)(b)).

Decoupling of a Douglas fir canopy: a look into the subcanopy with continuous vertical temperature profiles

Abstract. Complex ecosystems such as forests make accurately measuring atmospheric energy and matter fluxes difficult. One of the issues that can arise is that parts of the canopy and overlying atmosphere can be turbulently decoupled from each other, meaning that the vertical exchange of energy and matter is reduced or hampered. This complicates flux measurements performed above the canopy. Wind above the canopy will induce vertical exchange. However, stable thermal stratification, when lower parts of the canopy are colder, will hamper vertical exchange. To study the effect of thermal stratification on decoupling, we analyze high-resolution (0.3 m) vertical temperature profiles measured in a Douglas fir stand in the Netherlands using distributed temperature sensing (DTS). The forest has an open understory (0–20 m) and a dense overstory (20–34 m). The understory was often colder than the atmosphere above (80 % of the time during the night, >99 % during the day). Based on the aerodynamic Richardson number the canopy was regularly decoupled from the atmosphere (50 % of the time at night). In particular, decoupling could occur when both u*<0.4 m s−1 and the canopy was able to cool down through radiative cooling. With these conditions the understory could become strongly stably stratified at night. At higher values of the friction velocity the canopy was always well mixed. While the understory was nearly always stably stratified, convection just above the forest floor was common. However, this convection was limited in its vertical extent, not rising higher than 5 m at night and 15 m during the day. This points towards the understory layer acting as a kind of mechanical “blocking layer” between the forest floor and overstory. With the DTS temperature profiles we were able to study decoupling and stratification of the canopy in more detail and study processes which otherwise might be missed. These types of measurements can aid in describing the canopy–atmosphere interaction at forest sites and help detect and understand the general drivers of decoupling in forests.

Diet of the European bison (Bison bonasus) in a forest habitat estimated by DNA barcoding

Re-introduction of large herbivores is increasingly used as a tool in nature management and for restoration of more biodiverse habitats. This study investigated the diet of recently introduced European bison, Bison bonasus, in a forest habitat in Bornholm, Denmark, with the purpose of evaluating its adaptation to the new habitat and assessing its potential for facilitating development towards a more open and species-rich forest. Metabarcoding of 39 bison dung samples collected during June–August identified 71 plant taxa belonging to 36 families as diet objects, comprising 56% forbs, 20% trees, 17% graminoids and 7% shrubs. The broad composition of the diet shows the capacity of the bison to adjust to new habitats and exploit a variety of different habitats when foraging, including meadows and other wet areas. Among the most frequently consumed plant taxa were the shrub Rubus idaeus, a number of coarse grass species and most tree species found in the habitat. Rubus idaeus were by far the most abundant taxa, constituting 44% of all the DNA sequences. The results suggest that foraging by bison can contribute towards limiting domination by understory shrubs and high, coarse grasses. Over an extended time period, foraging by bison is expected to promote development towards a lower and more open understory and herbaceous layer in the forest habitats.

Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Nymphalidae) Oviposition Selection Favors More Vigorous Hosts

Oviposition search behaviors and host-plant selection play a critical role in the individual and population success of phytophagous insects. These characters are particularly important for specialists and metapopulations. The Ozark Baltimore Checkerspot Euphydryas phaeton ozarkae (Masters 1968) Nymphalidae specializes on Smooth Yellow False Foxglove Aureolaria flava (L. 1753, Farwell 1918) Orobanchaceae and has a metapopulation structure. We examined oviposition search behaviors of E. p. ozarkae using many of the same variables from a study on the nominate subspecies, the Baltimore Checkerspot Euphydryas phaeton phaeton (Drury 1773). Insight into host selection was obtained by comparing characteristics between plants with and without egg masses. Relationships among habitat conditions (and management therein) and the most selected plant characteristics were also determined. We found E. p. ozarkae to be highly selective of oviposition plants, expressing higher values associated with host-plant searching than E. p. phaeton. Butterflies consistently oviposited on plants with the greatest height, area, number of stalks, and number of leaves within a given study site. As average plant vigor increased, however, selection of the highest character values converged and became less prominent. In general, important plant characters were greater in habitats with a more open understory and canopy, which were associated with routine fire management. Continued habitat restoration in the Ozark and Boston Mountain regions and perpetual maintenance using prescribed fire (as appropriate seasonally) may positively affect the Ozark Baltimore Checkerspot by improving plant characters selected by these butterflies.

Perception of predation risk by African giant pouched rats (Cricetomys sp. nov) is higher in forest-edge microhabitats

How rodents perceive predation risk may alter their seed foraging behaviour and therefore potentially influence the recruitment of tree species. In this study we used two methods to investigate the effect of predation risk on habitat use by the African giant pouched rat (Cricetomys sp. nov) in Ngel Nyaki forest reserve, Nigeria. The first method was ‘giving up density’ (GUD), an index of perceived risk of predation at an artificial food patch, and the second was the ‘spool-and-line’ approach, whereby unravelling spools attached to rodent bodies are used to trace their tracks. For our GUD experiment, we chose four major sites in the forest; two representative of core habitat and two at the forest edge. Additionally, three characteristic microsites were used in the GUD experiment: dense understory, open understory and near-burrows. We hypothesised that GUDs would be lower on every succeeding observation day as rats learn to use the food patches, higher GUDs would be observed in the forest edges and open microsites, and rats would show preference for the microhabitats with least exposure to potential predators. In support of our first hypothesis, we found that GUDs were highest on the first experimental nights of every session. We also found that GUDs in the forest edges were higher than GUDs in the forest core. Lower GUDs were observed close to the rat burrows and in dense understory microsites, even though these differences were not statistically significant. Tracking of rat movements using the spool-and-line method overall revealed an even use across microhabitats, with a weak preference for those with logs, dense understory or exposed ground. Overall, our results suggest that vegetation density on a microhabitat scale has little or no effect on the perception of predation risk by African giant pouched rats.

Spotted owl foraging patterns following fuels treatments, Sierra Nevada, California

ABSTRACTWestern dry conifer forests continue to experience increased severe, stand‐replacing wildfire that is outside of historical precedent. Fuels treatments, landscape‐scale modifications of forest fuels and structure, are likely to remain a management tool to modify fire behavior and restore ecological resilience. The impacts of fuels treatments to listed species such as spotted owls (Strix occidentalis) remain uncertain and are contested because of limited available information. To evaluate spotted owl foraging habitat selection in a landscape recently modified by forest fuels‐reduction treatments, we radio‐marked and tracked 10 California spotted owls (S. o. occidentalis) for 2 years immediately following fuels treatment installation in the northern Sierra Nevada, California, USA. We categorized fuels treatments into 3 types: mechanical thin, installed within the study area as landscape‐scale fire breaks characterized by even tree spacing, open understory, and low canopy cover, or group selections; understory thin, a hand‐removal of small trees and shrubs; and understory thin followed by underburn, a controlled surface‐fuel burn that left the overstory intact. We described post‐treatment habitat using forest structural metrics derived from a Light Detection and Ranging (LiDAR) dataset that was collected 1 year after fuels treatments were completed. We collected 436 spotted owl foraging locations during 2 breeding seasons and evaluated breeding season home range size and composition using a resource selection function. We assessed possible contributors to owl foraging patterns by comparing a priori hypotheses in an information‐theoretic approach and using randomly generated points that estimated available habitat. Spotted owl breeding season home ranges contained fuels treatments in proportion to their availability on the landscape and averaged 17.1% treated area. Within the home range, owl foraging locations in the post‐treatment landscape were best predicted by lower proportions of gaps than anticipated at random, steeper slopes, and minimized distance from the owl's site center. Our results suggest that moderate to high proportions of gaps, typically a feature of forest fuels reduction and restoration treatments, may reduce the probability of spotted owl foraging. © 2018 The Wildlife Society.

Occupancy and habitat use by six species of forest ungulates on Tiwai Island, Sierra Leone

Forest ungulates in West Africa are common bushmeat species and are subject to habitat degradation through deforestation. Based on historical data, there are possibly 12 species of forest Bovidae and Tragulidae found in eastern Sierra Leone. We used camera trapping to assess occupancy by forest ungulates on and around a small protected area, Tiwai Island, Sierra Leone. We then assessed habitat over two field seasons during 2008–2011 for those species where we had sufficient numbers of detections. We detected 6 of 12 potential species and obtained enough data to further assess the habitat of two species. Species detected included the black duiker (Cephalophus niger), bongo (Tragelaphus eurycerus), bushbuck (Tragelaphus scriptus), Maxwell’s duiker (Philantomba maxwellii), water chevrotain (Hyemoschus aquaticus) and yellow-backed duiker (Cephalophus silvicultor). Among detected species, the bongo is considered near threatened. Several of the species not detected might be extirpated from the region, but for several species we found no records of them in the area. For the two species with sufficient detections for analysis, we found that Maxwell’s duikers were common throughout woody and swamp habitat and yellow-backed duikers preferred old growth forests with open understory. Despite widespread deforestation in Sierra Leone, a recent civil war and continued bushmeat trade, it appears that small wildlife refuges such as Tiwai Island continue to provide sanctuary for many of the forest ungulates of the region.Conservation implications: The Guinea Rainforest ecosystem of West Africa has undergone significant human impact and deforestation, negatively impacting all aspects of the biodiversity of the region. In addition, a long-standing civil war in Sierra Leone further exacerbated conservation concerns of many wildlife species. There are some recognised reserves in Sierra Leone, but small reserves managed by local people and conservation organisations have a role to play. Our work on Tiwai Island, along the Moa River in Sierra Leone, demonstrated that a significant proportion of the forest dwelling ungulate biodiversity of the region has been maintained in a small reserve despite isolation and effects of the war. Our work also suggests that Tiwai Island continues to have significant ecological value for ungulate conservation in the region and should be considered a model for establishment of other small reserves to help maintain the region’s biodiversity.

Thermal biology of eastern box turtles in a longleaf pine system managed with prescribed fire

Fire can influence the microclimate of forest habitats by removing understory vegetation and surface debris. Temperature is often higher in recently burned forests owing to increased light penetration through the open understory. Because physiological processes are sensitive to temperature in ectotherms, we expected fire-maintained forests to improve the suitability of the thermal environment for turtles, and for turtles to seasonally associate with the most thermally-optimal habitats. Using a laboratory thermal gradient, we determined the thermal preference range (Tset) of eastern box turtles, Terrapene carolina, to be 27–31°C. Physical models simulating the body temperatures experienced by turtles in the field revealed that surface environments in a fire-maintained longleaf pine forest were 3°C warmer than adjacent unburned mixed hardwood/pine forests, but the fire-maintained forest was never of superior thermal quality owing to wider Te fluctuations above Tset and exposure to extreme and potentially lethal temperatures. Radiotracked turtles using fire-managed longleaf pine forests maintained shell temperatures (Ts) approximately 2°C above those at a nearby unburned forest, but we observed only moderate seasonal changes in habitat use which were inconsistent with thermoregulatory behavior. We conclude that turtles were not responding strongly to the thermal heterogeneity generated by fire in our system, and that other aspects of the environment are likely more important in shaping habitat associations.

Responses of invasive predators and native prey to a prescribed forest fire

Fire shapes biome distribution and community composition worldwide, and is extensively used as a management tool in flammable landscapes. There is growing concern, however, that fire could increase the vulnerability of native fauna to invasive predators. We developed a conceptual model of the ways in which fire could influence predator–prey dynamics. Using a before–after, control–impact experiment, we then investigated the short-term effects of a prescribed fire on 2 globally significant invasive mesopredators (red fox, Vulpes vulpes, and feral cat, Felis catus) and their native mammalian prey in a fire-prone forest of southeastern Australia. We deployed motion-sensing cameras to assess species occurrence, collected predator scats to quantify diet and prey choice, and measured vegetation cover before and after fire. We examined the effects of the fire at the scale of the burn block (1,190 ha), and compared burned forest to unburned refuges. Pre-fire, invasive predators and large native herbivores were more likely to occur at sites with an open understory, whereas the occurrence of most small-and medium-sized native mammals was positively associated with understory cover. Fire reduced understory cover by more than 80%, and resulted in a 5-fold increase in the occurrence of invasive predators. Concurrently, relative consumption of medium-sized native mammals by foxes doubled, and selection of long-nosed bandicoots (Perameles nasuta) and short-beaked echidnas (Tachyglossus aculeatus) by foxes increased. Occurrence of bush rats (Rattus fuscipes) declined. It was unclear if fire also affected the occurrence of bandicoots or echidnas, as changes coincided with normal seasonal variations. Overall, prescribed fire promoted invasive predators, while disadvantaging their medium-sized native mammalian prey. Further replication and longer-term experiments are needed before these findings can be generalized. Nonetheless, such interactions could pose a serious threat to vulnerable species such as critical weight range mammals. Integrated invasive predator and fire management are recommended to improve biodiversity conservation in flammable ecosystems.

Loss of preferred habitat and pollen limitation threatens reproduction in a rare mountain Paeonia delavayi

Paeonia delavayi is a wild tree peony species endemic to high-altitude regions in southwestern China. Recent agricultural land expansion, however, not only causes its dwindling population size, but also poses a severe threat to its long-term persistence. Since our knowledge of the reproductive biology of P. delavayi is very limited, and some management misconceptions have further exacerbated the already worrisome situation, the aim of the present study is to provide some scientific evidence regarding habitat preference and breeding system of P. delavayi, and to help correct some management misconceptions. Specifically, morphological traits of P. delavayi populations growing in two different habitats (i.e., the open area versus forest understory), including basal stem diameter, plant height and flower numbers per plant, were measured and compared with each other. A range of floral manipulation experiments was further conducted to study the extent of self-compatibility and pollen limitation. The results showed that P. delavayi preferred the open habitat over forest understory as it generally grew bigger with thicker stems, and produced a higher number of flowers in the former habitat. Therefore, the open habitat should receive immediate priority for conservation action instead of being converted to agricultural land; also, P. delavayi is pollen limited, as evidenced by the fact that experimental flowers receiving supplemental non-self pollen generally displayed elevated seed production than flowers subjected to other treatments (e.g., non-supplemental self pollen, non-supplemental non-self pollen and supplemental self pollen), which is consistent with reported observations that alpine plants are more likely to be pollen-limited than lowland plants. We suggest that human intervention might be necessary to guarantee the long-term persistence of P. delavayi as harsh alpine environment, intense competition for pollinators and different anthropogenic perturbations co-limit its reproductive success.

Contrasting fire damage and fire susceptibility between seasonally flooded forest and upland forest in the Central Amazon using portable profiling LiDAR

Abstract Fire is an increasingly important agent of forest degradation in the Amazon, but little attention has been given to the susceptibility of seasonally flooded forests to fire. Satellite images suggest that forests flooded seasonally by nutrient-poor black waters are more susceptible to fire and may suffer greater fire damage than nearby upland forests. Reasons for this difference may include the presence of a root mat, more fine fuel as litter and a drier understory in the flooded forest. We investigated this difference in the field, hypothesizing that differences in the aboveground structure of the pre-burn forest can contribute to the difference in impacts of, and susceptibility to, fires. We employed a portable profiling LiDAR (PPL), first to compare damage between adjacent black water seasonally flooded and upland forests that were burned by the same fire event, and to then assess pre-fire canopy structure attributes known to affect fire susceptibility. For both assessments, we used PPL-derived metrics of leaf area and vertical and horizontal variation in the structure of vegetation in the canopy. Four years after the fire, the LiDAR metrics showed greater combined effects of high damage and slow recovery in the seasonally flooded forest; reduction of total Leaf Area Index (LAI) after burning was only 10% for upland forest but was 71% in the flood forest. Compared to unburned upland, the canopy of unburned flood forest had structural differences that increase susceptibility to fire, including drier microclimate. It had more gaps, a more open understory and a lower upper canopy. Small patches lacking canopy closure (LAI

Small Mammal Habitat Preferences in a Patchwork of Adjacent Reconstructed Grasslands Subject to Semiannual Burns

This study used small mammal capture-recapture methods within a mosaic of side-by-side prairie reconstructions to evaluate the relationship between floristic diversity, the effect of prescribed burns, and habitat use. This unique 10.4 ha study of opportunity consisted of multiple plots of three habitat types: low floristic diversity exotic cool-season grasses (CSG), low floristic diversity grass plantings dominated by native warm-season grasses (WSG), and floristically diverse, mixed prairie (MP) plantings with 45 species of forbs. Data for calculating small mammal abundances (new captures/trap effort) were determined by trapping in August following spring burns in 2002 and 2004, and unburned years in 2003 and 2005. Fire-positive species (meadow jumping mice, Peromyscus spp.) preferred fields with a more open understory (MP plantings), and a reduced thatch thickness and leaf litter layer (burned fields). Fire-negative species (meadow voles, northern short-tailed shrews) populated all restorations (CSG, WSG, MP plantings) but only during the unburned years when the fields provided a high density of vegetative cover. Even though the distinct floristic diversity found within the three reconstruction types influenced small mammal foraging preferences, the effect of semiannual burns on floristic structures had a noteworthy impact on their distributions. The results of this study demonstrate an important take home message for restoration practitioners: techniques that promote differences in structural characteristics are just as important as creating plantings with high floristic diversity.

Spatial and temporal structure of a mesocarnivore guild in midwestern north America

Carnivore guilds play a vital role in ecological communities by cascading trophic effects, energy and nutrient transfer, and stabilizing or destabilizing food webs. Consequently, the structure of carnivore guilds can be critical to ecosystem patterns. Body size is a crucial influence on intraguild interactions, because it affects access to prey resources, effectiveness in scramble competition, and vulnerability to intraguild predation. Coyotes (Canis latrans), bobcats(Lynx rufus),grayfoxes(Urocyoncinereoargenteus),raccoons (Procyonlotor), redfoxes(Vulpesvulpes), and striped skunks (Mephitis mephitis) occur sympatrically throughout much of North America and overlap in resourceuse,indicatingpotential forinterspecificinteractions. Although muchisknownabouttheautecology ofthe individual species separately, little is known about factors that facilitate coexistence and how interactions within this guild influence distribution, habitat use, and temporal activity of the smaller carnivores. To assess how habitat autecology and interspecific interactions affect the structure of this widespread carnivore guild, we conducted a large-scale, non-invasive carnivore survey using an occupancy modeling framework. We deployed remote cameras during 3-week surveys to detect carnivores at 1,118 camera locations in 357 2.6-km 2 sections (3-4 cameras/section composing a cluster) in the 16 southernmost counties of Illinois (16,058 km 2 ) during January-April, 2008-2010. We characterized microhabitat at each camera location and landscape-level habitat features for each camera cluster. In a multistage approach, we used information-theoretic methods to evaluate competing models for detection, species-specific habitat occupancy, multispecies co-occupancy, and multiseason (colonization and extinction) occupancy dynamics. We developed occupancy models for each species to represent hypothesized effects of anthropogenic features, prey availability, landscape complexity, and vegetative land cover. We quantified temporal activity patterns of each carnivore species based on their frequency of appearance in photographs. Further, we assessed whether smaller carnivores shifted their diel activity patterns in response to the presence of potential competitors. Of the 102,711 photographs of endothermic animals, we recorded photographs of bobcats (n ¼412 photographs), coyotes (n ¼1,397), gray foxes (n ¼546), raccoons (n ¼40,029), red foxes (n ¼149), and striped skunks (n ¼2,467). Bobcats were active primarily during crepuscular periods, and their activity was reduced with precipitation and higher temperatures. The probability of detecting bobcats decreased after a bobcat photograph was recorded, suggesting avoidance of remote cameras after the first encounter. Across southern Illinois, bobcat occupancyatthecamera-locationandcamera-clusterscale(b clocal ¼0.24 � 0.04,cameracluster b ccluster ¼0.75 � 0.06) was negatively influenced by anthropogenic features and infrastructure. Bobcats had high rates of colonization (b ¼0.86) and low rates of extinction (be ¼0.07), suggesting an expanding population, but agricultural land was less likely to be colonized. Nearly all camera clusters were occupied by coyotes (b ccluster ¼0.95 � 0.03). At the local scale, coyote occupancy (blocal ¼0.58 � 0.03) was higher in hardwood forest stands with open understories than in other areas. Compared to coyotes, gray foxes occupied a smaller portion of the study area (b clocal ¼0.13 � 0.01, bcluster ¼0.29 � 0.03)atallscales.Atthescaleofthecameracluster,grayfoxoccupancywashighestinfragmentedareas withhighproportionsofforest,andpositivelyrelatedtoanthropogenicfeatureswithin100%home-rangebuffers.Red foxesoccupiedasimilarproportionofthestudyareaasgrayfoxes( blocal ¼0.12 � 0.02, b ccluster ¼0.26 � 0.04)butwere morecloselyassociatedwithanthropogenicfeatures.Onlyanthropogenicfeaturemodelsmadeupthe90%confidence set at all scales of analysis for red foxes. Extinction probabilities at the scale of the camera cluster were higher for both gray foxes (be ¼0.57) and red foxes (be ¼0.35) than their colonization rates (gray fox b ¼0.16, red fox b ¼0.06), suggestingbothspeciesmaybedeclininginsouthernIllinois.Stripedskunksoccupiedalargeportionofthestudyarea ( b clocal ¼0.47 � 0.01, b ccluster ¼0.79 � 0.03)andwereassociatedprimarilywithanthropogenicfeatures.Raccoonswere