Edwin M. Everham

Forest damage and recovery from catastrophic wind

The literature on the effects of catastrophic wind disturbance (windstorms, gales, cyclones, hurricanes, tornadoes) on forest vegetation is reviewed to examine factors controlling the severity of damage and the dynamics of recovery.Wind damage has been quantified in a variety of ways that lead to differing conclusions regarding severity of disturbance. Measuring damage as structural loss (percent stems damaged) and as compositional loss (percent stems dead) is suggested as a standard for quantifying severity. Catastrophic wind produces a range of gaps from the size caused by individual treefalls to much larger areas. The spatial pattern of damage is influenced by both biotic and abiotic factors. Biotic factors that influence severity of damage include stem size, species, stand conditions (canopy structure, density), and the presence of pathogens. Abiotic factors that influence severity of damage include the intensity of the wind, previous disturbance, topography, and soil characteristics.Recovery from catastrophic wind disturbance follows one of four paths: regrowth, recruitment, release, or repression. The path of recovery for a given site is controlled both by the severity of disturbance and by environmental gradients of resources. Recovery is influenced also by frequency of wind disturbance, which varies across geographical regions.To develop robust theories regarding catastrophic wind disturbance, the relative roles of different abiotic and biotic factors in controlling the patterns of severity of damage must be determined. These patterns of severity and environmental gradients must then be tied to long-term dynamics of recovery.ResumenLa literatura sobre los efectos de disturbios catastróficos del viento (tormentas, ventarrones, ciclones, huracánes, tornados) sobre la vegetatión de bosque es revisada para examinar los factores que controlan la severidad del daño y la dinámica de recuperación.El daño del viento puede ser cuantificado en varias formas, lo cualo conlleva a diferir en las conclusiones en cuanto a la severidad del disturbio. Medir daños como la pérdida estructural (por ciento de tallos dañados) y la pérdida compositional (porcentaje de tallos muertos) son normas sugeridas para cuantificar la severidad. Los vientos catastróficos producen una extensión de aperturas de gran tamaño causados por árboles caídos sobre muchas otras áreas mayores. El patrón espacial de daño es influenciado por factores abióticos y bióticos. Factores bióticos que influyen severamente al daño pueden ser tamaño del tallo, especie, conditión de tolerancia (estructura del dosel, densidad), y la presencia de patogénos. Factores abióticos que influyen severamente sobre el daño incluyen la intensidad del viento, disturbios anteriores, topografía, y las características del suelo.La recuperatión de las catástrofes causados por el viento siguen uno de cuatro patrones: crecimiento, reclutaje, liberar o reprimir. La trayectoria de recuperatión para un lugar es controlado por ambos: por lo severo del disturbio y por los gradientes ambientales del recurso. La recuperatión es influenciada también por la frecuencia del disturbio por viento, el cual varia sobre el globo.Para desarrollar una fuerte teoría en cuanto a disturbios catastróficos por viento, los roles relativos de los factores abióticos y bióticos en el control de modelos de severidad de daño tienen que ser determinados. Estos modelos de severidad y gradientes ambientales tienen que ser enlazados para una dinámica de recobro a largo plazo.РЕФЕРАТОбзор литературы о во здействии катастроф ических ветров (штормов, цикло нов, ураганов, смерчей) на лесную растительность с цел ью выявления факторо в, влияющих на величину ущерба и на д инамику рекомпенсац ии.Ущерб от ветра оценив ается различными мет одами, приводящими к разным выводам. Измерение ущ ерба как структурного воздей ствия (процент повреж денных стволов) и как композиционног о воздействия (процен т погибших стволов) предложено в качестве стандарта. Катастрофический ве тер образует серию пр оплешин, размер которых колеблется в широком диапазоне. Пространственная конфигурация ущерба находится под воздей ствием как биотических, так и аби отических факторов. Б иотические факторы величины уще рба включают: размер с твола, особенности особи, ус ловия древостоя (стру ктура и плотность листвы) и пр исутствие патогенов. Абиотические факторы величины уще рба включают интенси вность ветра, предшествующие атмо сферные возмущения, т опографию и характеристики почв ы.Рекомпенсация после катастрофического в етрового воздействия следует по одному из четырех п утей: спонтанное возобнов ление, спонтанное зам ещение другими древесными особями, п одавление нижних яру сов древостоя (нуждающееся в их “выс вобождении” от листв ы верхнего яруса), нашествие сорн яковой растительнос ти. Какой из путей рекомпенсации возобладает, зависит от масштаба атмосферного возмущ ения и от целого ряда с редовых градиентов. Рекомпен сация также зависит о т глобально изменчивой частоты в етровых возмущений.Для создания продукт ивных теорий измерен ия ветрового ущерба нео бходима оценка разли чных биотических и абиотических факто ров, влияющих на велич ину и конфигурацию ущерба. Последняя, а также сре довые градиенты должны быт ь увязаны с долгосроч ной динамикой рекомпенсации.

Responses of Tree Species to Hurricane Winds in Subtropical Wet Forest in Puerto Rico: Implications for Tropical Tree Life Histories

JESS K. ZIMMERMAN,* EDWIN M. EVERHAM III,t ROBERT B. WAIDE,* D. JEAN LODGE,*? CHARLOTTE M. TAYLOR,t** and NICHOLAS V. L. BROKAW? *Terrestrial Ecology Division, University of Puerto Rico, PO Box 363682, San Juan, PR 00936, tSUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA, IDepartment of Biology, University of Puerto Rico, Rio Piedras, PR 00931, ?Manomet Observatory, Box 1770, Manomet, MA 02345, USA

LAND USE HISTORY, ENVIRONMENT, AND TREE COMPOSITION IN A TROPICAL FOREST

The effects of historical land use on tropical forest must be examined to understand present forest characteristics and to plan conservation strategies. We compared the effects of past land use, topography, soil type, and other environmental variables on tree species composition in a subtropical wet forest in the Luquillo Mountains, Puerto Rico. The study involved stems > 10 cm diameter measured at 130 cm above the ground, within the 16-ha Luquillo Forest Dynamics Plot (LFDP), and represents the forest at the time Hurricane Hugo struck in 1989. Topography in the plot is rugged, and soils are variable. Historical documents and local residents described past land uses such as clear-felling and selective logging followed by farming, fruit and coffee production, and timber stand im- provement in the forest area that now includes the LFDP. These uses ceased 40-60 yr before the study, but their impacts could be differentiated by percent canopy cover seen in aerial photographs from 1936. Using these photographs, we defined four historic cover classes within the LFDP. These ranged from cover class 1, the least tree-covered area in 1936, to cover class 4, with the least intensive historic land use (selective logging and timber stand improvement). In 1989, cover class 1 had the lowest stem density and pro- portion of large stems, whereas cover class 4 had the highest basal area, species richness, and number of rare and endemic species. Ordination of tree species composition (89 species, 13 167 stems) produced arrays that primarily corresponded to the four cover classes (i.e., historic land uses). The ordination arrays corresponded secondarily to soil characteristics and topography. Natural disturbances (hurricanes, landslides, and local treefalls) affected tree composition, but these effects did not correlate with the major patterns of species distributions on the plot. Thus, it appears that forest development and natural disturbance have not masked the effects of historical land use in this tropical forest, and that past land use was the major influence on the patterns of tree composition in the plot in 1989. The least disturbed stand harbors more rare and endemic species, and such stands should be protected.

Influence of a Large-scale Removal of an Invasive Plant (Melaleuca quinquenervia) on Home-range Size and Habitat Selection by Female Florida Panthers (Puma concolor coryi) within Big Cypress National Preserve, Florida

Abstract The control of invasive exotic plants is often deemed important for managing native wildlife, but surprisingly little research exists that evaluates benefits to wildlife, including species of conservation concern. Melaleuca quinquenervia (Melaleuca) is an invasive, non-native, broad-leaved tree that aggressively displaces native plant communities in south Florida. We used land-cover maps to document changes in plant communities and radio-telemetry data to compare habitat selection and mean home-range size of the endangered Puma concolor coryi (Florida Panther) within Big Cypress National Preserve (BCNP) during a Melaleuca removal projects removal phase (1991–1997) and the ensuing maintenance and habitat recovery phase (1998–2006). During the removal phase, Panthers incorporated areas infested by Melaleuca as components of their home range. Following >99.9% removal of Melaleuca, we documented pronounced increases in total cover of native upland forest (227%), wetland forest (211%), and prairie (54%) communities. During the habitat recovery phase, Panther habitat selection in the study area included significantly more upland forest within home-range core areas, and mean home-range size contracted by 16%. However, similar reductions in mean home-range size were not observed during the same time period for the regional population of radio-collared Panthers occupying contiguous conservation lands in south Florida. Although our findings are correlational and do not demonstrate cause and effect, the increase in native plant community cover, the increased use of native plant communities by Panthers, and the reduction in mean home-range size following the removal of Melaleuca are consistent with what would be expected if improvements in habitat quality reduced Panther home-range size requirements. Restoration of native plant communities and particularly native forest types, therefore, may have improved habitat quality for the Florida Panther and resulted in smaller home-range sizes and a potential increase in carrying capacity within BCNP.

Anurans as Biological Indicators of Restoration Success in the Greater Everglades Ecosystem

Abstract The Picayune Strand Restoration Project is being conducted as part of the Comprehensive Everglades Restoration Plan to restore hydrology and habitat in Southwest Florida. This study evaluated the success of the restoration activities by examining anuran species richness and relative abundance in relation to various restoration treatments, which included restored areas, un-restored areas, and natural wetlands. Anuran observations were conducted using nocturnal audible call surveys and dip netting. Univariate results indicated that: the lowest species richness and relative abundance values occurred within the un-restored areas, richness significantly increased in all restored areas relative to un-restored areas, abundance increased in some restored areas but not others, and highest richness and abundance were documented in the natural wetlands. Multivariate analysis confirmed these patterns and also indicated that the anuran species assemblages were significantly different between restoration treatments. Furthermore, the presence or absence of Lithobates sphenocephalus utricularius (Southern Leopard Frog), Gastrophryne carolinensis (Eastern Narrow-mouthed Toad), and Hyla femoralis (Pine Woods Treefrog) may be used to document restoration success or hydrologic disturbance, respectively. These findings suggest that the restoration activities can be effective and that anurans could be used as performance measures of restoration success.

Herpetofaunal community change in multiple habitats after fifteen years in a southwest Florida preserve, USA.

Herpetofaunal declines have been documented globally, and southern Florida, USA, is an especially vulnerable region because of high impacts from hydrological perturbations and nonindigenous species. To assess the extent of recent change in herpetofauna community composition, we established a baseline inventory during 1995-97 at a managed preserve in a habitat rich area of southwest Florida, and repeated our sampling methods fifteen years later (2010-11). Nine drift fence arrays were placed in four habitat types: mesic flatwood, mesic hammock, depression marsh, and wet prairie. Trapping occurred daily for one week during 7-8 sampling runs in each period (57 and 49 total sampling days, respectively). Species richness was maintained in mesic hammock habitats but varied in the others. Catch rates of several native species (Anaxyrus terrestris, Lithobates grylio, Anolis carolinensis, Nerodia fasciata) declined significantly. Other native species (Lithobates sphenocephalus, Siren lacertian, and Notophthalmus viridescens piaropicola) that were abundant in 1995-97 declined by greater than 50%. Catch rate of only two species (the nonindigenous Anolis sagrei and the native Diadophis punctatus) increased significantly. Hierarchical cluster analysis indicated similarity within habitat types but significant dissimilarity between sampling periods, confirming shifts in community composition. Analysis of individual species’ contributions to overall similarity across habitats shows a shift from dominance of native species in the 1990s to increased importance of nonindigenous species in 2010-11. Although natural population fluctuations may have influenced differences between the two sampling periods, our results suggest considerable recent change in the structure and composition of this southwest Florida herpetofaunal community. The causes are unknown, but hydrological shifts and ecological impacts of nonindigenous species may have contributed.

Terrestrial Snake Environmental DNA Accumulation and Degradation Dynamics and its Environmental Application

Abstract There is an increasing need for effective biomonitoring tools that quantify patterns of habitat occupancy by reptile species. Environmental DNA (eDNA) has been regarded as an emerging tool to detect specific target species; however, the dynamics of accumulation and degradation of eDNA in terrestrial environments are poorly understood. This study determines the time required for terrestrial snakes to leave enough eDNA behind to become detectable (accumulation time) as well as its persistence (degradation time). By targeting mitochondrial cytochrome oxidase subunit I and 12S rRNA genes of Red Cornsnakes (Pantherophis guttatus) in a controlled laboratory setting, we found that eDNA can be detected 3.5 h after the snakes had contact with soil and for up to 6 d after their removal. Estimated accumulation rate of Pantherophis guttatus eDNA per gram of snake biomass per hour was 12.6 μg. We also evaluated the applicability of eDNA detection under field conditions by targeting the mitochondrial cytochrome b gene of a cryptic invasive species in South Florida, Burmese Pythons (Python bivittatus). Soil samples were derived from two groups of field sites: telemetry-monitored refugia (i.e., radiotelemetry evidence of python presence) and telemetry-absent refugia (i.e., no telemetry evidence, but monitored with a burrow camera at time of sample collection). We were able to detect the presence of python eDNA in 66.7% of the telemetry-monitored sites that fit within our laboratory-defined residence and degradation time window. Additionally, at the telemetry-absent sites, no eDNA from Burmese Pythons was detected and burrow cameras did not detect their presence. We concluded that eDNA technology using soil can be an effective detection tool for terrestrial snakes, particularly when used with other traditional tracking and sampling methods.